The present invention relates to a decoding apparatus and method, a program storage medium, and a program, which allow high-performance decoding of a modulation code encoded in accordance with a variable-length table. A 17PP-SISO decoder 181 performs SISO decoding on a signal supplied from a PR-SISO decoder 81 by using a Viterbi decoding algorithm or a BCJR decoding algorithm in accordance with a trellis represented by paths corresponding, in a one-to-one fashion, to overall transitions in an entire encoding process in accordance with an encoding table 201 of a 17PP code. A resultant SISO-decoded signal is supplied to a turbo decoder 84 via a deinterleaver 83. The turbo decoder 84 performs turbo decoding on the signal output from the 17PP-SISO decoder 181. The present invention can be applied to a recording/reproducing apparatus for recording/reproducing a signal on/from a storage medium such as a high-density optical disk.

When a signal is recorded on a storage medium such as a magnetic disk or an optical disk, the signal is modulation-encoded before it is recorded such that when the recorded signal is reproduced, the amplitude of the read signal can be controlled and a clock signal can be correctly reproduced. In the reproduction process, the original waveform is reproduced taking into account the fact that the signal reproduced from a medium is influenced by an immediately previous signal, and most likelihood data is determined from the reproduced signal on the basis of the characteristic of the recorded signal by means of a PRML (Partial Response Maximum-Likelihood) scheme or the like.
FIG. 1 shows an example of a conventional recording/reproducing apparatus 1 using the PRML technique. The recording/reproducing apparatus 1 includes a modulation encoder 11, a PR communication channel 12, and decoder 13.
The modulation encoder 11 includes an encoding table 41-1 of modulation codes used in encoding of an input signal under a particular restriction. The modulation encoder 11 encodes an input signal into a particular modulation code in accordance with the encoding table 41-1 and outputs a resultant encoded signal produced under the particular restriction to a PR (Partial Response) communication channel 12. A specific example of the restriction is a DC free restriction. Use of the DC free restriction causes numbers of occurrences of 0s and 1s to become substantially equal for a sufficiently long period. Another example of the restriction is a (d, k) restriction that requires that the minimum and maximum numbers of successive 0s be d and k, respectively.
The PR communication channel 12 includes a recording/reproducing unit 21 and an equalizer 22. In the PR communication channel 12, recording/reproducing is performed, for example, in a PR2 (Partial Response Class 2) recording/reproducing channel. The recording/reproducing unit 21 converts the encoded signal received from the modulation encoder 11 into a NRZI (non return to zero inverted) coded signal and stores the resultant NRZI-coded signal on a storage medium mounted on or embedded in the recording/reproducing unit 21 by means of a mark edge recording method. On the other hand, in the reproduction operation, the recording/reproducing unit 21 reads the encoded signal from the storage medium via the PR-2 channel and supplies the read encoded signal to the equalizer 22. The equalizer 22 performs PR equalization using waveform interference on the received encoded signal so as to achieve a target equalization characteristic. The resultant equalized signal is supplied to the decoder 13.
The decoder 13 includes a PR-Viterbi decoder 31 and a modulation decoder 32 and serves to decode the signal supplied from the equalizer 22. From the signal received from the PR communication channel 12, the PR-Viterbi decoder 31 determines, based on NRZI encoding and the PR-2 channel, the trellis representation indicating time-to-time state transitions associated with the encoding process and performs Viterbi decoding in accordance with the determined trellis representation of the NRZI encoding and the PR-2 channel. A resultant Viterbi-decoded signal to the modulation decoder 32. The modulation decoder 32 includes an encoding table 41-2 that is the same as the encoding table 41-1 disposed in the modulation encoder 11 (hereinafter, encoding tables 41-1 and 41-2 will be generically referred to as encoding tables 41, if it is not necessary to distinguish them from each other). The modulation decoder 32 performs modulation decoding on the signal supplied from the PR-Viterbi decoder 31 and outputs a resultant modulation-decoded signal to a following stage (not shown).
In recent years, it has become popular to use a high-performance error-correction code such as a turbo code or an LDPC (Low Density Parity Check) code in various applications of communications and broadcasting. There is an increasing need for using such a high-performance error-correction code also in applications associated with storage media. For example, when a turbo code is used in the recording/reproducing apparatus 1 described above, a turbo encoder is additionally disposed at a stage in front of the modulation encoder 11, and a turbo decoder for decoding the turbo code is additionally disposed at a stage following the modulation decoder 32. In this structure, not only information taking a value of 0 or 1 (hard information but also information (soft information or soft decision information) indicating the degree of likelihood of the hard information is input to the turbo decoder located at the stage following the modulation decoder 32. That is, it is necessary that soft input be supplied to the decoder of the turbo code or the LDPC code. This means that when a modulation code is decoded by the modulation decoder 32 located at the stage in front of the turbo encoder or the LDPC encoder, it is necessary to determine soft output.
In general, a soft output associated with a code is determined by using a trellis representation indicating time-sequential transitions corresponding to a state transition table indicating a time-to-time encoding process by means of a BCJR (Bhal-Cocke-Jeinek-Raviv) algorithm or a SOVA (Soft-Output Viterbi Algorithm). The trellis representation can be easily determined when an input signal is decoded using a convolution code. However, when decoding is performed using a non-linear modulation code, it is not necessarily easy to determine the trellis representation. Recent researches have revealed that a trellis representation is possible for some types of modulation codes using a simple encoding table, such as a (1, 7) RLL (Run Length Limited) code (according to the standard of ECMA (Electronic Computer Manufacturers Association)-195) used in recording/reproducing on or from a magnetooptical disk, and thus a turbo decoder may be concatenated with a modulation decoder using a (1, 7) RLL code ("Turbo Decoding with Run Length Limited Code for Optical Stage" (E. Yamada et al., The Japan Society of Applied Physics, Vol. 41, pp. 1753-1756, March, 2002 (hereinafter referred to as Non-Patent Document 1). In RLL codes, the number of "0s" between a "1" and a next "1" in a modulation code is limited, and a particular RLL code with a minimum run length d indicating the minimum number of "0s" between adjacent "1s" and a maximum run length k is represented by (d, k)RLL.
FIG. 2 shows an example of a configuration of a conventional recording/reproducing apparatus 51 using an RLL code concatenated with a turbo code. In this example shown in FIG. 2, the modulation encoder 11 shown in FIG. 1 is replaced with an encoder 61 and the decoder 13 is replaced with a decoder 62. FIGS. 1 and 2 will also be referred to when the present invention is described later.
The encoder 61 includes a turbo encoder 71, an interleaver 72, and an RLL (Run Length Limited) encoder 73. The turbo encoder 71 includes an element encoder 91, an interleaver 92, an element encoder 93, and a decimator 94. The turbo encoder 71 performs turbo encoding on an input signal and supplies a resultant turbo-coded signal to the interleaver 72.
A signal input from the outside is simultaneously applied to the element encoder 91 and the interleaver 92. The element encoder 91 generates a parity bit string 1 from the input signal and supplies the resultant parity bit string 1 to the decimator 94. The interleaver 92 interleaves the signal that was also input to the element encoder 91 and supplies a resultant interleaved signal to the element encoder 93. The element encoder 93 generates a parity bit string 2 from the interleaved signal supplied from the interleaver 92 and supplies the resultant parity bit string 1 to the decimator 94. The decimator 94 decimates the parity bit string 1 and the parity bit string 2 and multiplexes the resultant decimated parity string 1 and parity bit string 2 thereby generating a turbo-coded signal. The resultant turbo-coded signal is supplied to the interleaver 72.
The interleaver 72 interleaves a turbo-coded signal supplied from the turbo encoder 71 and supplies the resultant interleaved signal to the RLL encoder 73. The PLL encoder 73 has a (1, 7) RLL encoding table 101. The PLL encoder 73 performs (1, 7) RLL encoding on the signal received from the interleaver 72 in accordance with the RLL encoding table 101 and outputs the resultant signal over the PR communication channel 12.
The decoder 62 includes a PR-SISO (Soft-Input Soft-Output) decoder 81, an RLL-SISO decoder 82, a deinterleaver 83, and a turbo decoder 84, and serves to decode the signal supplied from the equalizer 22. From the signal received from the PR communication channel 12, the PR-SISO decoder 81 determines, based on NRZI encoding and the PR-2 channel, the trellis representation indicating time-sequential state transitions in the time-to-time encoding process represented in the state transition table and then performs SISO (Soft-Input Soft-Output) decoding based on the determined trellis representation of the NRZI encoding and the PR-2 channel. The resultant SISO-decoded signal (soft information) is supplied to the RLL-SISO decoder 82.
The RLL-SISO decoder 82 determines, based on (1, 7) RLL encoding table 101 disposed in the PLL encoder 73, the trellis representation indicating time-sequential state transitions in the time-to-time encoding process represented in the state transition table and performs SISO decoding on the signal received from PR-SISO decoder 81 in accordance with the determined trellis representation of (1, 7) RLL. The resultant SISO-decoded signal is supplied to the deinterleaver 83.
Referring to FIGS. 3 and 4, a trellis representation of (1, 7) RLL encoding is described below. FIG. 3 shows an example of a state transition table of (1, 7) RLL encoding, and FIG. 4 shows an example of a trellis representation, that is, a representation of time-sequential transitions indicated in the state transition table shown in FIG. 3. In the example shown in FIG. 3, the state transition table represents an encoding process in a period from a current time and a next time. In this state transition table shown in FIG. 3, for a better understanding, state information indicating "previous-time state" and "current-time state" are added to the (1, 7) RLL encoding table 101.
In the state transition table shown in FIG. 3, previous-time state", "previous-time output", "previous-time input", "current-time output", "current-time input", and "current-time state" are described from right to left in each row, and from top to bottom, a transition from a "previous-time state" of S0 in which the "previous-time output" is 0 and the "previous-time input" is 00, a transition from a "previous-time state" of S1 in which the "previous-time output" is 0 and the "previous-time input" is 01, a transition from a "previous-time state" of S2 in which the "previous-time output" is 0 and the "previous-time input" is 10, a transition from a "previous-time state" of S3 in which the "previous-time output" is 0 and the "previous-time input" is 11, a transition from a "previous-time state" of S4 in which the "previous-time output" is 1 and the "previous-time input" is 00, and a transition from a "previous-time state" of S5 in which the "previous-time output" is 1 and the "previous-time input" is 01, are described.
In the trellis representation shown in FIG. 4, circles on the left-hand side indicate "states at the previous time" shown in FIG. 3, arrows indicate transitions from the respective "states at the previous time" to "states at the current time", symbols to the right and left of a slash of each label on each arrow indicate a corresponding "current-time input" and "current-time output" shown in FIG. 3, circles to the right of the heads of respective arrows indicate "states at the current time" shown in FIG. 3.
Thus, in the examples shown in FIGS. 3 and 4, when the "state at the previous time" is S0, a transition occurs depending on the given input as follows. If 00 is input as the "input at the current time" then the "output at the current time" is given by 001 and the "state at the current time" becomes S4. If 01 is input as the "input at the current time" then the "output at the current time" is given by 001 and the "state at the current time" becomes 5. If 10 is input as the "input at the current time" then the "output at the current time" is given by 000 and the "state at the current time" becomes S2. If 11 is input as the "input at the current time" then the "output at the current time" is given by 000 and the "state at the current time" becomes S3. When the state at the previous time is S1, a transition occurs depending on the given input as follows. If 00 is input as the "input at the current time" then the "output at the current time" is given by 001 and the "state at the current time" becomes S4. If 01 is input as the "input at the current time" then the "output at the current time" is given by 001 and the "state at the current time" becomes S5. If 10 is input as the "input at the current time" then the "output at the current time" is given by 000 and the "state at the current time" becomes S2. If 11 is input as the "input at the current time" then the "output at the current time" is given by 000 and the "state at the current time" becomes S3.
When the state at the previous time is S2, a transition occurs depending on the given input as follows. If 00 is input as the "input at the current time" then the "output at the current time" is given by 101 and the "state at the current time" becomes S4. If 01 is input as the "input at the current time" then the "output at the current time" is given by 101 and the "state at the current time" becomes S5. If 10 is input as the "input at the current time" then the "output at the current time" is given by 010 and the "state at the current time" becomes S2. If 11 is input as the "input at the current time" then the "output at the current time" is given by 010 and the "state at the current time" becomes S3. When the state at the previous time is S3, a transition occurs depending on the given input as follows. If 00 is input as the "input at the current time" then the "output at the current time" is given by 010 and the "state at the current time" becomes S0. If 01 is input as the "input at the current time" then the "output at the current time" is given by 100 and the "state at the current time" becomes S1. If 10 is input as the "input at the current time" then the "output at the current time" is given by 100 and the "state at the current time" becomes S2. If 11 is input as the "input at the current time" then the "output at the current time" is given by 100 and the "state at the current time" becomes S3.
When the state at the previous time is S4, a transition occurs depending on the given input as follows. If 00 is input as the "input at the current time" then the "output at the current time" is given by 001 and the "state at the current time" becomes S4. If 01 is input as the "input at the current time" then the "output at the current time" is given by 001 and the "state at the current time" becomes S5. If 10 is input as the "input at the current time" then the "output at the current time" is given by 010 and the "state at the current time" becomes S2. If 11 is input as the "input at the current time" then the "output at the current time" is given by 010 and the "state at the current time" becomes S3. When the state at the previous time is S5, a transition occurs depending on the given input as follows. If 00 is input as the "input at the current time" then the "output at the current time" is given by 010 and the "state at the current time" becomes S0. If 01 is input as the "input at the current time" then the "output at the current time" is given by 000 and the "state at the current time" becomes S1. If 10 is input as the "input at the current time" then the "output at the current time" is given by 000 and the "state at the current time" becomes S2. If 11 is input as the "input at the current time" then the "output at the current time" is given by 000 and the "state at the current time" becomes S3.
As described above, in the trellis representation (state transition table) of the (1, 7) RLL encoding, possible transitions at a particular time are represented for respective six states S0 to S5. In any state, if an input signal is given, an output signal is uniquely determined. Thus, the RLL-SISO decoder 82 can correctly perform SISO decoding in accordance with the (1, 7) RLL trellis representation.
Referring again to FIG. 2, the RLL-SISO decoder 82 supplies the SISO-decoded signal to the deinterleaver 83. The deinterleaver 83 deinterleaves the signal supplied from the RLL-SISO decoder 82 in a manner reverse to the interleaving performed by the interleaver 72, and the deinterleaver 83 supplies the resultant deinterleaved signal to the turbo decoder 84.
The turbo decoder 84 includes an interpolator 111, an element decoder 112, an interleaver 113, an element decoder 114, and a deinterleaver 115. The turbo decoder 84 performs turbo decoding on the signal (soft information) received from the deinterleaver 83 and outputs a resultant decoded signal to the outside (not shown). The interpolator 111 performs interpolation on the signal received from the deinterleaver 83 and supplies a resultant signal to the element decoder 112 and the element decoder 114. The element decoder 112 performs SISO decoding on the signal received from the interpolator 111 and supplies the resultant SISO-decoded signal together with reliability information to the element decoder 114 via the interleaver 113. The element decoder 114 performs SISO decoding on the signal received from the interpolator 111 by using the reliability information received from the element decoder 112. The resultant SISO-decoded signal and reliability information are supplied to the element decoder 112 via the deinterleaver 115. The above element decoding process is iterated several times. After the iteration of the element decoding process, the element decoder 114 performs a final decision and outputs a decision result to a following stage (not shown).
Note that the BCJR algorithm or the SOVA is used in the SISO decoding in the PR-SISO decoder 81, the RLL-SISO decoder 82, the element decoder 112 and the element decoder 114 shown in FIG. 2.
In the recording/reproducing apparatus 51, as described above, the RLL-SISO decoder 82 determines the trellis representation of (1, 7) RLL encoding in accordance with the (1, 7) RLL encoding table 101, and soft information is easily obtained. This allows the turbo decoder 84 to be located at the stage following the RLL-SISO decoder 82.
In recent years, a 17PP (Parity Preserve/Prohibit RMTR (Repeated Minimum Transition Runlength) code has been used in recording/reproducing on high-density optical disks. In the 17PP code, a complicated variable-length encoding table is used, as described, for example in U.S. Pat. No. 6,496,541B1.
In the variable-length encoding table associated with the 17PP code, the bit length of an "input" is not fixed unlike in the (1, 7) RLL code in which the input has a fixed bit length such as "00" or "01". This means that when an "input" such as 00 is given, an "output" is not necessarily uniquely determined. Thus, unlike the (1, 7) RLL code, it is difficult to determine the trellis representation of the 17PP code from the variable-length encoding table of the 17PP code, because the bit length of the input is not fixed. Even if it is possible to determine the trellis representation directly from the state transition table indicting time-to-time encoding process, the resultant trellis representation becomes very complicated and includes a huge number of states. Thus, SISO decoding of a modulation code using a variable-length table such as a 17PP code is practically impossible.

Decoding device and method, program recording medium, and program using modulation code encoded in accordance with a variable length table


An electric lamp includes a light-transmissive lamp envelope defining an enclosed volume, the lamp envelope having a press seal at one end thereof and the press seal having a recess along a bottom edge thereof, at least one lamp filament disposed in the enclosed volume of the lamp envelope, electrical leads extending through the press seal on opposite sides of the recess and connected to the lamp filament, and an exhaust tube extending through the recess in the press seal to the enclosed volume of the lamp envelope. An insulating base is typically secured to the press seal. The exhaust tube located in the recess is at least partially shielded against breakage.

This invention relates to electric lamps and, more particularly, to electric lamps wherein the lamp envelope is sealed with a press seal, and an exhaust tube extends through the press seal.
One common type of incandescent electric lamp is a so-called S-8 wedge type lamp used for automobile brake light, turn signal and tail light applications. Such lamps typically include one or more filaments located within a lamp envelope. Electrical leads extend through a press seal for connection to an energy source. In addition, an exhaust tube extends through the press seal to the enclosed volume of the lamp envelope. The exhaust tube is used to fill the enclosed volume of the lamp envelope with a desired gas fill after formation of the press seal. The exhaust tube is then tipped off, or sealed, by heating the glass tube. The lamp is mounted in a plastic base that attaches to the press seal. A lamp assembly, including the lamp and the base, is inserted into a socket in the automobile or other vehicle.
Current lamps of this type have an elongated exhaust tube that extends beyond the press seal. It has been found that the current lamp configuration with an elongated exhaust tube is somewhat fragile and can fail upon incorrect insertion into the lamp socket. Recently, wedge lamp usage has shifted to automatic insertion techniques. This process has resulted in increased lamp failures upon insertion, due to off-axis insertion of the lamp assembly into the socket, allowing the press seal to pivot inside the base. The exposed exhaust tube contacts the inside wall of the plastic base and temporarily carries the insertion force load. A result of this type of loading may be a mechanical failure of the exhaust tube. The failure upon incorrect insertion may not be detected until a later time.
Wedge-type incandescent electric lamps which utilize an insulating base are disclosed, for example, in U.S. Pat. No. 4,603,278, issued Jul. 29, 1986 to Devir et al.; U.S. Pat. No. 4,752,710, issued Jun. 21, 1988 to Devir et al.; U.S. Pat. No. 4,877,992, issued Oct. 31, 1989 to Devir; U.S. Pat. No. 4,979,082, issued Dec. 18, 1990 to Devir; U.S. Pat. No. 5,008,588, issued Apr. 16, 1991 to Nakahara; U.S. Pat. No. 5,061,873, issued Oct. 29, 1991 to Belliveau; U.S. Pat. No. 5,186,669, issued Feb. 16, 1993 to Holman et al; U.S. Pat. No. 5,278,741, issued Jan. 11, 1994 to Ehrman; and U.S. Pat. No. 6,056,417 issued May 2, 2000 to Cheng. None of the prior art known to Applicants has addressed the breakage problem described above.
Accordingly, there is a need for electric lamps having press seal configurations which provide exhaust tube protection and for methods of making such electric lamps.
According to a first aspect of the invention, an electric lamp is provided. The lamp comprises a light-transmissive lamp envelope defining an enclosed volume, the lamp envelope having a seal and the seal having a recess, a light source disposed in the enclosed volume of the lamp envelope, electrical leads extending through the seal and connected to the light source, and an exhaust tube extending through the recess in the seal to the enclosed volume of the lamp envelope. The seal preferably comprises a press seal.
The exhaust tube includes an exposed portion external to the press seal. A substantial part of the exposed portion of the exhaust tube is positioned within the recess, so that the exhaust tube is at least partially shielded against breakage. The exposed portion of the exhaust tube external to the press seal may have a length that is less than the length of the press seal. The exhaust tube may have an outside diameter that is less than the thickness of the press seal for further shielding of the exhaust tube.
According to another aspect of the invention, a lamp assembly is provided. The lamp assembly comprises an electric lamp and a lamp base. The electric lamp may be configured as described above. The lamp base is secured to the press seal.
According to a further aspect of the invention, a method is provided for making an electric lamp. The method comprises the steps of providing a light-transmissive lamp envelope having an interior volume and an opening communicating with the interior volume, positioning a filament assembly and an exhaust tube in the opening, heating the lamp envelope at least in the region of the opening, forming the lamp envelope into a press seal such that electrical leads of the filament assembly and the exhaust tube extend through the press seal into the interior volume of the lamp envelope, and pushing the exhaust tube toward the interior volume of the lamp envelope with the lamp envelope heated to form a recess in the press seal where the exhaust tube extends into the lamp envelope.

Electric lamp having press seal configuration for exhaust tube protection


A wafer heating apparatus which is capable of quickly cooling by improving the cooling rate of the heater section is provided.

Semiconductor devices are extremely important products used in diverse products ranging from industrial use to home use. A semiconductor chip which constitutes the semiconductor device is manufactured by, for example, forming various circuits on a silicon wafer and cutting the wafer into the chips of predetermined size.
In a semiconductor manufacturing process where various circuits are formed on a silicon wafer, a wafer heating apparatus is used to heat the semiconductor wafer such as silicon wafer (hereinafter referred to simply as wafer) when forming a thin film of semiconductor, etching the film and baking the resist film.
Conventional semiconductor manufacturing apparatuses can be divided into batch operation type which heats a plurality of wafers simultaneously and sequential operation type which heats the wafers one by one. The sequential operation type has an advantage that the temperature can be controlled more accurately, although it can process less wafers at a time. While the use of semiconductor heating apparatuses of the batch operation type has been predominant in the past, use of semiconductor heating apparatuses of the sequential operation type where the wafers are processed one by one has been increasing as the wafer size increases from 8 inches to 12 inches while wiring of the semiconductor devices becomes finer and higher accuracy is required in controlling the wafer processing temperature.
When the sequential operation type is employed, however, it is required to reduce the time taken to process each wafer since the number of wafers processed at a time decreases. Therefore, there is a strong demand for the wafer heating apparatus to reduce the time required in cooling down as well as in heating. Accordingly in the wafer heating apparatus, it is a common practice to place a heater section, comprising a plate-shaped member which has a resistive heating member, in a casing and provide a cooling nozzle in the casing so as to forcibly cool the heater section by supplying a cooling medium from the nozzle (Japanese Unexamined Patent Publication (Kokai) No. 2003-100818 and Japanese Unexamined Patent Publication (Kokai) No. 2004-063813).
Recently wafer heating apparatuses made of ceramics are widely used as the wiring of the semiconductor devices becomes finer and higher accuracy is required in controlling the wafer processing temperature.
The wafer heating apparatuses made of ceramics are disclosed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 2001-135684, Japanese Unexamined Patent Publication (Kokai) No. 2001-203156, Japanese Unexamined Patent Publication (Kokai) No. 2001-313249 and Japanese Unexamined Patent Publication (Kokai) No. 2002-76102. FIG. 19 shows a wafer heating apparatus 171 made of ceramics disclosed in Japanese Unexamined Patent Publication (Kokai) No. 2001-203156.
The wafer heating apparatus 171 made of ceramics comprises a plate-shaped ceramic member 172 and a casing 179 as the major components, wherein the plate-shaped ceramic member 172 made of nitride ceramics or carbide ceramics is secured to the opening of the bottomed casing 179 made of a metal such as aluminum, by means of bolt 180 via an insulating connecting member 174 made of a resin, of which top surface is used as a mounting surface 173 to mount the wafer W thereon, and a resistive heating member 175 having concentric configuration as shown in FIG. 20 is provided on the bottom surface of the plate-shaped ceramic member 172 thereby forming a heater section.
With this configuration, a cooling medium is injected from a nozzle 182 into a space delimited by the plate-shaped ceramic member 172 and the casing so as to circulate and is discharged through a discharge port 183, thereby cooling the heater section.
In order to form a uniform film over the entire surface of the wafer W or provide uniform heat-reaction condition of the resist film by using the wafer heating apparatus 171 made of ceramics of such a constitution, it is important to make the temperature distribution uniform by minimizing the temperature difference across the surface of wafer, and it is necessary to heat and cool down the wafer in a short period of time. In addition, it is necessary to change the temperature setting of the wafer heating apparatus 171 in order to vary the wafer temperature, and it is required to heat the wafer heating apparatus 171 made of ceramics in a short period of time and cool it down in a short period of time.
Japanese Unexamined Patent Publication (Kokai) No. 2002-83848 discloses that disturbance of the flow of the cooling medium can be mitigated by keeping the surface roughness of the bottom surface of the casing within a predetermined value, and that it is made possible to improve the efficiency of heating and cooling.
Japanese Unexamined Patent Publication (Kokai) No. 2002-100462 discloses that heating rate and cooling rate of the wafer can be increased by controlling the heat capacity of the wafer heating apparatus 171 made of ceramic to 5000 J/K or less. However, the casing 179 has a heat capacity 3.3 times that of plate-shaped ceramic member 173 or more, and the ratio S/V of the surface area S of the casing 179 to the volume V of the casing 179 is less than 5 (l/cm), and therefore the cooling time cannot be sufficiently reduced.
Thus it has been taking relatively long time to change the set temperature of heating the wafer with any of the prior art technologies, and there has been a demand for a wafer heating apparatus capable of changing the temperature in a shorter period of time.
In the meantime, it has been in practice to decrease the temperature difference across the surface of wafer by controlling the distribution of resistance of the resistive heating member 175 having band shape or controlling the temperature of the resistive heating member 175 having band shape separately, and it has been proposed to increase the amount of heat generated from the surrounding area in the case of a structure susceptible to heat sink.
But any of the proposals have problems that a very complicated structure and complex control are required, and there is a demand for a wafer heating apparatus capable of heating with uniform temperature distribution with a simple structure.
Moreover, since the wafer heating apparatus 171 is vulnerable to the light, heat, processing gas and other influences when used in a semiconductor manufacturing apparatus, the resistive heating member 175 is required to have durability against oxidization and other attack on the surface. For this reason, it has been proposed to coat the resistive heating member 175 with an insulation layer on a part or whole of the surface thereof, so as to improve the durability of the resistive heating member 175 (refer to Japanese Unexamined Patent Publication (Kokai) No. 2001-297857).
Since the insulation layer can also serve as a heat insulator for the resistive heating member 175, it may make an obstacle in quickly cooling down the wafer heating apparatus 171 which has been heated. Therefore, there has been a wafer heating apparatus where surface roughness Ra of the insulation layer is controlled in a range from 0.01 to 10 μm in an attempt to improve the cooling effect (refer to Japanese Unexamined Patent Publication (Kokai) No. 2001-297858).

Wafer heating apparatus and semiconductor manufacturing apparatus

Abstract: The wafer heating apparatus comprises a plate-shaped member having two opposing principal surfaces with one of the principal surfaces serving as a mounting surface to mount a wafer thereon and the other principal surface having a band-shaped resistive heating member formed thereon, power feeder terminals connected to the resistive heating member for supplying electric power to the resistive heating member, a casing provided to cover the power feeder terminals on the other surface of the plate-shaped member and a nozzle of which tip faces the other surface of the plate-shaped member for cooling the plate-shaped member, wherein the position of the tip of the nozzle as projected onto the other surface of the plate-shaped member is located between the bands of the resistive heating member.


A noise codebook selects a code most suitable to the characteristics of an input speech vector from an inside quantification table. Furthermore, a codebook renewal circuit determines a correlative value between a noise code selected by the noise codebook and the input speech vector, subsequently calculates a multiplication value for each of noise codes to generate a renewal code by using the multiplication value with respect to the code selected most frequently by the coding processing at the time of voice. Renewal processing is preformed by replacing a desired code of the codebook with the renewal code. Furthermore, the renewal code is sent to a multiplexing circuit together with a renewal flag value to be sent to a decoding device by using the superfluous bit portion of an unvoice frame.

1. Field of the Invention
The present invention relates to a technique for coding and decoding speech signals in a communication system such as, for example, a mobile communication system or the like.
2. Description of the Related Art
In a conversation on a telephone, time for speaking from a speaker and time for hearing speech from the other party, alternately exists. Here, when the speaker hears the voice of the other party of the communication, information sent to the other party becomes "unvoice. In other words, since they are not speaking not much information is required. Thus, there is proposed a variable rate type speech coding and decoding system which heightens a transmission rate at the time of voice (at the time of speaking), and which lowers the transmission rate at the time of listening (at the time of hearing the voice of the other party) (refer to the reference described below). According to this coding and decoding method, there is provided an advantage of lowering an average transmission rate while maintaining a speech quality.
Reference: DeJaco A., Gardner W., Jacobs P., Lee C. "QCELP": The North American CDMA Digital Cellular Variable Rate Speech Coding Standard", IEEE Workshop on Speech Coding for Telecommun., pp. 5-6 (1993).
The variable rate type coding and decoding method can provide a large advantage when using a transmission channel which allows a variable transmission volume. However, when a transmission channel having a fixed transmission volume is used, the amount of information transmitted by the transmission channel is small, a fixed amount of the transmission channel will be occupied with the result that there is no meaning in that the transmission channel is rendered variable.
Furthermore, in the speech coding and decoding method, a favorable speech quality can be obtained in the case where a correlation between the quantification code used in coding and the speech information is favorable while a sufficient speech quality can not be obtained in the case where the correlation is poor.

Coding device and decoding device of speech signal, coding method and decoding method


A method for generating toll information for vehicle devices in a road-toll system with a toll center and geographically distributed radio beacons. The method includes providing a set of location data of toll-requiring geo-objects from the respective local environment of a beacon in this beacon, recording a sequence of position data of a vehicle device in this vehicle device, if the aforementioned vehicle device is in the transmitting/receiving range of a beacon: receiving the location-data set from this beacon in the vehicle device, comparing the position-data sequence with the received location-data set in the vehicle device in order to generate toll information therefrom, and if the above-mentioned vehicle device is in the transmitting/receiving range of a beacon: transmitting the toll information from the vehicle device via the beacon to the toll center. The invention further relates to a vehicle device, a beacon and a monitoring device for such a road-toll system.

"Short-range" radio communication is understood in the present description to mean radio distances (cell radii) of up to several kilometers
In their functions, role distributions and interfaces, modern road-toll systems follow the principles defined in ISO Standard 17573, "Road Transport and Traffic Telematics—Electronic Fee Collection—System Architecture for Vehicle Related Transport Services." According to the latter there are essentially two basic types of systems.
"infrastructure-bound" systems, e.g., DSRC (dedicated short-range communication) toll systems, in which roadside infrastructure (roadside equipment, RSE), e.g., DSRC radio beacons, locates and charges tolls to the OBUs; and
"infrastructure-less" systems such as GNSS (global navigation satellite systems) toll systems, in which the OBUs autonomously locate themselves and transmit either "raw" position data (as so-called "thin clients"), or "finished" toll information calculated from the position data and toll maps (as so-called "thick clients") to the toll center via a mobile-radio network (cellular network, CN).
Infrastructure-bound toll systems achieve a high degree of toll-charging security, but require extensive roadside infrastructure for this, in order to be able to locate OBUs over a large area, because the positional resolution of the location-finding is given from the size of the transmitting/receiving ranges and the number of beacons. Infrastructure-less toll systems, on the other hand, have basically unlimited coverage due to the self-locating-finding ability of the OBUs, but require enormous computational power (server farm) in the toll center for "thin client" systems in order to generate toll information from the raw position data of the OBUs, or in the case of "thick client systems," require correspondingly expensive OBUs which can record and process all the toll maps of the toll coverage area, and this also presumes a correspondingly expensive distribution and updating of the toll maps via the mobile-radio network. This data traffic consumes bandwidth and, not least important, is expensive for the user.

Method and device for generating toll information in a road-toll system


A control device for a hybrid vehicle provided with an engine and a motor as driving sources, and a storage battery device which stores regenerative energy obtained by output from the engine or by regenerative operation of the motor during deceleration of the vehicle. The control device includes: a vehicle speed detection unit which detects speed of the vehicle; a deceleration fuel cut determination unit which determines whether supply of fuel to the engine is stopped during deceleration of the vehicle; and a brake detection unit which detects operation of a brake, wherein regenerative braking is stopped when operation of the brake is detected by the brake detection unit if the vehicle speed detected by the vehicle speed detection unit is lower than a predetermined speed and if it is determined by the deceleration fuel cut determination unit that the supply of fuel to the engine is not stopped.

1. Field of the Invention
The present invention relates to a control device for hybrid vehicles. More specifically, the present invention relates to a control device for a hybrid vehicle which enables improvement in salability at low vehicle speed and low revolution range of the engine.
2. Description of Related Art
Hybrid vehicles provided with a motor as an auxiliary driving source for running the vehicle in addition to an engine have been conventionally known.
A parallel hybrid vehicle in which output from an engine is auxiliary assisted by a motor is a variation of the hybrid vehicle. In the parallel hybrid vehicle, output from the engine is auxiliary assisted by the motor when the vehicle is accelerated, and various controls, such as stop of fuel supply and charging of batteries using deceleration regenerative braking, are performed when the vehicle is decelerated so that the needs of the driver can be satisfied while maintaining remaining charge of the batteries (as disclosed in, for instance, Japanese Unexamined Patent Application, First Publication No. 7-123509).
In some of the above-mentioned hybrid vehicles, especially in vehicles provided with manual transmission (so called MT vehicles), regenerative braking is performed in accordance with the revolution number of the engine in a deceleration mode when deceleration fuel cut is not carried out at low vehicle speed and the accelerator is not pressed as in the case of, for instance, traveling on a curve at low speed.
However, when the vehicle enters a deceleration mode and the revolution number of the engine further decreases, and regenerative braking is stopped in order to prevent engine stall, the regenerative braking is carried out again since the load on the engine decreases by the amount corresponding to the stop of the regenerative braking and the revolution number of the engine increases.
Accordingly, hunting of the revolution number of the engine is caused by repeating stop and restart of the regenerative braking. In particular, when a large braking force is applied to the engine by means of a brake control and regenerative braking, such as for the case where the brake pedal is pressed, shock generated by stopping and restarting the regenerative braking increases, and this is not preferable in terms of salability.
Accordingly, an object of the present invention is to provide a control device for a hybrid vehicle which enables improvement in salability by stopping unnecessary regenerative braking by taking into account the driver""s intention to stop the vehicle and by eliminating hunting of the revolution number of the engine within a low speed range.
In order to achieve the above object, the present invention provides a control device for a hybrid vehicle provided with an engine (for instance, an engine E in an embodiment described later) and a motor (for instance, a motor M in the embodiment described later) as driving sources, and a storage battery device (for instance, a battery 3 in the embodiment described later) which stores regenerative energy obtained by output from the engine or by regenerative operation of the motor during deceleration of the vehicle, the control device including: a vehicle speed detection unit (for instance, a vehicle speed sensor S1 in the embodiment described later) which detects speed of the vehicle; a deceleration fuel cut determination unit (for instance, a step S074 shown in FIG. 3 in the embodiment described later) which determines whether supply of fuel to the engine is stopped during deceleration of the vehicle; and a brake detection unit (for instance, a brake switch S4 in the embodiment described later) which detects operation of a brake, wherein regenerative braking is stopped (for instance, a cruise mode shown in step S077 in the embodiment described later) when operation of the brake is detected by the brake detection unit (for instance, xe2x80x9cYESxe2x80x9d in step S074C in the embodiment described later) if the vehicle speed detected by the vehicle speed detection unit is lower than a predetermined speed and if it is determined by the deceleration fuel cut determination unit that the supply of fuel to the engine is not stopped (for instance, xe2x80x9cNOxe2x80x9d in step S074 in the embodiment described later).
In accordance with another aspect of the invention, in the control device for a hybrid vehicle, the vehicle is further provided with a manual transmission (for instance, a manual transmission (MT) T in the embodiment described later).
According to the above control device for a hybrid vehicle, since the regenerative braking can be stopped by taking into account the driver""s intention to stop when the brake pedal is applied if the vehicle speed is lower than a predetermined speed and it is not during a deceleration fuel cut state, it becomes possible to prevent hunting, in which increase and decrease of the engine revolution number is repeated as in the case where regenerative operation is continued, and hence the salability can be improved. Also, since the vehicle speed is low and the brake is applied, the degree of regenerative amount that can be obtained is small and no adverse effect is imparted on energy management.
The present invention also provides a control device for a hybrid vehicle provided with an engine (for instance, an engine E in an embodiment described later) and a motor (for instance, a motor M in the embodiment described later) as driving sources, and a storage battery device (for instance, a battery 3 in the embodiment described later) which stores regenerative energy obtained by output from the engine or by regenerative operation of the motor during deceleration of the vehicle, the control device including: a vehicle speed detection unit (for instance, a vehicle speed sensor S1 in the embodiment described later) which detects speed of the vehicle; a deceleration fuel cut determination unit (for instance, a step S074 shown in FIG. 3 in the embodiment described later) which determines whether supply of fuel to the engine is stopped during deceleration of the vehicle; a brake detection unit (for instance, a brake switch S4 in the embodiment described later) which detects operation of a brake, and a throttle opening degree detection unit (for instance, a throttle opening degree sensor S6 in the embodiment described later) which detects an opening degree of a throttle, wherein regenerative braking is carried out with a degree corresponding to a revolution number of the engine (as shown in, for instance, FIG. 5 which indicates setting of the regenerative amount in the deceleration mode in step S078, and step S104), if the opening degree of throttle detected by the throttle opening degree detection unit is smaller than a predetermined value (for instance, xe2x80x9cNOxe2x80x9d in step S074D in the embodiment described later), when the vehicle speed detected by the vehicle speed detection unit is lower than a predetermined speed, it is determined by the deceleration fuel cut determination unit that the supply of fuel to the engine is not stopped (for instance, xe2x80x9cNOxe2x80x9d in step S074 in the embodiment described later), and the operation of brake is not detected by the brake detection unit (for instance, xe2x80x9cNOxe2x80x9d in step S074C in the embodiment described later).
According to the above control device for a hybrid vehicle, it becomes possible to set an appropriate regenerative amount in accordance with the engine revolution number when a proper deceleration state is determined based on the throttle opening degree. Accordingly, regenerative operation can be smoothly performed.


An imaging apparatus with divers resolution includes a light source, a reflection lens set, a major lens and an image-capture unit. The light source is used to illuminate a document for further generating a document image. The reflection lens set includes a plurality of reflection lenses for forwarding the document image consecutively to the major lens. The major lens is used to receive the document image transported by the reflection lens set and to form the document image at a focal point thereof. The image-capture unit includes a plurality of image-capture elements with various resolution for meeting divers usage requirements. While in usage, a suitable image-capture element with particular resolution can be shifted to the focal point of the major lens for performing the imaging.

(1) Field of the Invention
The invention relates to an imaging apparatus with divers resolution, and more particularly to which can perform document scanning according to a predetermined resolution setting by switching among divers image-capture elements with respective resolution defaults.
(2) Description of the Prior Art
An imaging apparatus or a scanner is one of popular computer peripherals. In an imaging apparatus, an interior image-capture unit such as a CCD is used to generate an image from a document rested upon a document plate. The image as a form of digital signals are then forwarded to a computer for further image processing or storage.
Referring now to FIG. 1, a conventional optical scanner is shown schematically. The optical scanner 1 includes a light source 10, a document carrier plate 12, a reflection lens set 14, a major lens 16 and an image-capture element 18. The light source 10 is usually a lengthy fluorescent tube for illuminating the document 2 rested upon the document carrier plate 12. The document carrier plate 12 is a transparent plate made of glass or acrylic for supporting the document 2 thereofupon. The reflection lens set 14 includes a plurality of reflection lenses, say 141, 142 and 143 for example. By providing these reflection lenses 141, 142 and 143, a proper light path for forwarding the document image can be established. In an imaging process, the reflection lens set 14 can receive and forward the document image captured from the document 2 rested upon the carrier plate 12. The document image is then sent to the major lens 16 via the reflection lenses 141, 142 and 143. In the art, the major lens 16 is a convex lens for focusing the document image to its focal point. The image-capture element 18 for capturing the document image is located right at the focal point for the major lens 16. In the art, the image-capture element 18 can be an electric charge coupling device (CCD) as an example.
Because the optical scanner is used to process document imaging and the imaging quality does highly depend upon the resolution of the image-capture element, a necessary condition for a scanner to have improved imaging quality is obvious that the scanner must include a high-resolution image-capture element. Generally, high resolution implies that the image-capture element needs to provide a huge number of pixels within a unit length of the document. Apparently, the more number of the pixels are required in the imaging process, the slower the imaging is performed.
Though a high-resolution scanner can provide better quality to the document image, yet plenty process time is required as an unavoidable tradeoff. However, for documents that the originals are already clear enough, for those that the originals include only simple drawing, or for those that clear copies are not required, a user might feel time-wasting to duplicate those document by using a high-resolution scanner. On the other hand, for the users to duplicate those documents, a simple, low-resolution and fast scanner may only meet the need. Therefore, to resolve the problem, some high-rank scanners in the market do provide a convenient switch function for the users being capable of determining if a document should apply a high-resolution imaging process or a low-resolution imaging process.
Currently, three methods as following have been applied to the switching mechanism of the aforesaid scanner. They are:                1. Integrating a zoom lens to the image-capture element;        2. Integrating a plurality of lens to the image-capture element; and        3. Integrating a plurality of lens to a plurality of image-capture elements.
Basically, a common ideology for all three methods to achieve the operation of resolution-alternating is to vary the focus of the major lens. Among these three aforesaid methods, method 3 might need much higher cost in production due to more components being applied. On the other hand, though the application of methods 1 and 2 might need fewer components, yet a complicate switching mechanism is required to render the focus alternation.
In the early development stage of the optical scanners, the adjusting of the imaging resolution is mainly done through varying the focus of the major lens due to the higher cost and lower resolution of the image-capture element (CCD, for example). However, current image-capture technology has been improved to an extend that lower production cost and higher resolution are feasible. Hence, developing a technique of applying a single major lens to integrate several image-capture elements with various resolution will definitely contribute a lot to the market competitiveness of the product.

Imaging apparatus with divers resolution


A mounting apparatus for a bucket of a front end loader vehicle. The mounting system allows the bucket to pivot up and over fixed objects when the leading edge of the bucket strikes an immovable object for the purpose of protecting the loader assembly, vehicle, and operator.

Commercial snow plows, front end loaders and snow blowers have a long history of use in removing snow from streets and highways. Over the past several decades the use of snow plows on light and medium duty trucks has become commonplace. Snow plows work well for clearing snow from roadways, particularly in open places and in areas where yearly snowfall totals are such that the snow can be readily pushed off the roadway. In densely populated urban areas, where real estate is at a premium, and in areas with large annual snowfalls, there is a need to be able to lift snow over snowbanks for deposit into large piles. Alternately, the snow is often lifted into dump trucks to be hauled and deposited elsewhere, or dumped into snow melting machines. In addition, snow blowers are widely used by people in clearing snow from their yards and sidewalks.
One of the issues related to the use of these snow clearing machines is that a great amount of stress is imparted to the structural components when plowing in areas such as those prone to frost heaving where manhole covers, and other relatively fixed objects, are struck by the moving scraping edge of the machine's clearing accessory. Not only do such encounters with immovable objects greatly shorten the life of these snow clearing machines, but they are also quite jarring to the machine operator and pose an enhanced risk of injury to the machine operator as well as others in the vicinity of the machines that are in operation.
Several devices have been developed for use with snow clearing machines, particularly, snow plows, whereby either the whole plow blade, or just a portion of it, pivots back up to about 90 degrees upon encountering a fixed object in the road (see for example U.S. Pat. Nos. 6,701,646 and 5,697,172, respectively). Such devices, while effective for some of the snow plow blades, are not compatible with some other snow clearing machines. For example, due to the different geometry of a loader bucket, the bucket's longitudinal depth combined with the required rear pivotal connections for lifting and dumping prevent such a pivoting back since such pivoting generally requires a pivot point on an angle greater than 45 degrees up from the leading edge. Also, since such buckets typically have a leading edge attached to the horizontal structure of the bucket bottom, the tilting back solutions are impractical because this would require tilting the whole bucket backwards by around 180 degrees. Consequently, there is a need for a device which allows the scraping edge of snow clearing machines to ride up over fixed objects upon impacting them, which thereby reduces the wear and tear on snow clearing machines while also enhancing the safety of the machine operator and the public at large.

Apparatus protecting vehicle with accessory when scraping edge of accessory strikes fixed object


The radar apparatus includes an antenna device including a transmitting antenna and a receiving antenna, a main body which generates a radar wave, transmits the radar wave from the transmitting antenna, and receives the radar wave reflected from an obstacle to be detected by the receiving antenna, and a cover member covering the main body and the antenna device on a side of a transmission direction of the radar wave and located out of contact with the main body and the antenna device. The cover member has a transmission portion allowing the radar wave to pass therethrough, a surface of the transmission portion facing the antenna device being inclined by an angle greater than 3 degrees with respect to an antenna surface of the receiving antenna.

1. Field of the Invention
The present invention relates to a radar apparatus, and a mounting structure for the radar apparatus.
2. Description of Related Art
As described, for example, in Japanese Patent Application Laid-open No. 2003-240838, it is known to mount a radar apparatus on the inner surface of a bumper of a vehicle so as to be covered by the bumper as a cover member.
However, when a radar apparatus is mounted on the inner surface of a bumper, there is possibility that the radar apparatus is damaged by the bumper when the bumper vibrates even slightly, or when the bumper is hit by a stone or the like.
It may occur that the radar apparatus is mounted not on the inner surface of the bumper, but fixed to a certain member located inside a vehicle body so that there is some distance between the radar apparatus and the bumper. However, in this case, since a transmitted radar wave is repeatedly reflected between the bumper and the surface of an antenna device of the radar apparatus, the detection characteristic of the reflected radar wave of the radar apparatus may become unstable, and accordingly, the obstacle detecting capability of the radar apparatus may be unstable.

Radar apparatus and mounting structure for radar apparatus


An ear-microphone for connection to a portable apparatus and use as a Frequency Modulation (FM) radio broadcast receiving antenna is provided. The ear-microphone includes an ear plug, a cable, a microphone, and a filtering unit. The ear plug is for connection to an earjack. The cable has a predefined length, has an earphone line whose one end is electrically connected to the ear plug and whose other end is electrically connected to at least one earphone. The microphone intervenes in an intermediate portion of the cable and is connected to the ear plug via a microphone line inside the cable. The filtering unit intervenes in the cable and is installed to have an Electro Static Discharge (ESD) protection function.

1. Field of the Invention
The present invention relates to an ear-microphone. More particularly, the present invention relates to an ear-microphone having an Electro Static Discharge (ESD) enhancing function.
2. Description of the Related Art
Recently, as a multimedia technology develops, portable electronic apparatuses having various functions are emerging. Examples of these apparatuses include a mobile terminal, a Motion Picture Expert Group Audio Layer-3 (MP3) player, a Portable Multimedia Player (PMP), and the like. These apparatuses have a convergence function that performs one or more functions in a combination.
In case of a mobile terminal, the mobile terminal can receive sky wave broadcasting (for example, ground wave Digital Multimedia Broadcasting (DMB)) or Frequency Modulation (FM) radio broadcasting, and reproduce a music file, or capture and reproduce a high quality moving image besides a basic communication function.
When performing these various additional functions, a user additionally uses an ear-microphone including an ear plug inserted into an earjack of a relevant apparatus. In a further case of a mobile terminal, an ear plug is provided to one end of a cable of a predefined length, and a pair of earphones is installed to the other end. In addition, a microphone is installed on the cable, so that a hands-free function is performed during communication.
The above-described plug uses a four-pole terminal, and each terminal is electrically insulated and installed. When the plug is inserted into the earjack, each terminal contacts a relevant pin installed at a relevant position of the earjack, so that each terminal performs a relevant function.
While a portable apparatus receives an FM radio broadcast, the above-described ear-microphone uses an earphone line and/or a microphone line of the ear-microphone as an antenna, without having an antenna unit inside the ear-microphone.
In this case, the ear-microphone additionally mounts therein a predefined protection device for protecting against an Electro Static Discharge (ESD) of the FM radio antenna. Since a standard of a relevant line does not exist, each apparatus analyzes FM radio performance and a trade-off of ESD protection to perform separate tuning, which is difficult.
In addition, as the number of additional functions gradually increases, such that the number of corresponding components also increases, it becomes difficult to ensure a space for installing a separate ESD device for an FM radio antenna inside an apparatus while maintaining a light weight and a slim profile.
Therefore, a need exists for an ear-microphone having an ESD enhancing function, realized to contribute to a slim profile and reliability improvement of a portable apparatus by not adding a separate device inside the portable apparatus.

Ear-microphone having ESD enhancing function


In one embodiment, a network switch includes multiple chips communicably coupled together and a buffered crossbar. Each chip is coupled to every other chip with two bi-directional serial channels and includes a slice of the buffered crossbar. One or more input ports, one or more output ports, and an input logic module are coupled to the plurality of chips, and the input logic module is configured to receive a packet of data, allocate the packet of data into one or more data fragments, and distribute the packet of data to the buffered crossbar. An output logic module is coupled to the chips and configured to retrieve the packet of data from the buffered crossbar, reconstruct the packet of data from the data fragments according to a gather scheme, and transmit the packet of data.

A network switch is a data switching device that forwards a data packet from a source network component to a destination network component. Typically, a network switch receives a packet from the source network component via an input port and sends a packet to the destination network component via an output port.


A light hardening device is provided and includes a light source having a plurality of LEDs supplied by an electrical energy source, and a cooling device arranged upstream of the light source and operable to cool the light hardening device. The LED arrangement is disposed on a rear surface of a cooling body and the light hardening device has a connection in the manner of a halogen glow lamp. Also, a light source is provided having a plurality of LEDs, a cooling body on which the LEDs are mounted, and a connector element and an overall exterior geometry, each of which corresponds to the respective connector element and overall exterior geometry of a conventional reflecting halogen glow lamp having a rated voltage of 12 volts.

The present invention relates to a light hardening device and a light source suitable for use in a light hardening device.
A conventional light hardening device is disclosed, for example, in U.S. Pat. No. 5,420,768. This conventional device includes a plurality of light diodes mounted on a common base body. The light emitted by the light diodes is conducted to a light guide and can be used, for example, for the light hardening of suitable polymerizable masses which are deployed, for example, in the dental practice.
It is further conventionally known to provide a cooling arrangement for the base body on which the light diodes are mounted.
It has already been proposed to use a cooling body as the base body, whereby, for example, reference is made to copending U.S. patent application Ser. No. 10/023,232. In accordance with the arrangement disclosed therein, a cooling body is provided which has numerous LEDs mounted on its base surface. The cooling body is encircled by ribbed elements and the light passing therefrom is conducted to a light guide, whereby a portion of the light exits after first being reflected by the ribbed elements which are arranged in front of the light guide and configured in opposition thereto.
The just described arrangement offers a basic good cooling of the LED arrangement.
To be sure, if for the purpose of achieving a maximum light output, the base surface of the cooling body is provided with a plurality of closely adjacent LED chips, then the cooling body becomes too hot in connection with an intensive outer cooling as a consequence of which, in accordance with the heretofore described conventional arrangement, a pre-determined distance between the LED chips must be maintained. The free surface surrounded by the chips serves at the same time as a reflective surface which reflects the light again which has been reflected from the mirrored inner counter cone (which has a geometry corresponding to that of the front ribbed element body) and the light is ultimately guided to the light guide.
U.S. Pat. No. 6,123,545 shows a device for curing polymerizable dental materials. In this device a conventional halogen lamp is employed.
This conventional approach has led, surprisingly, to the circumstance that exactly at the front ribbed element body, the ribbed element body is substantially heated so that, in fact, a water cooling arrangement has been proposed. A water cooling arrangement can, indeed, substantially improve the cooling effect, but such an arrangement increases the weight of the light hardening device to an extent that the device is too heavy for suitable hand deployment.
The present invention offers a solution to the challenge of providing a light hardening device as well as a light source which improves the light working efficiency xe2x80x94that is, the relationship or ratio between the light performance given thereby and the heat or warmth given off by the device.
The arrangement of the present invention offers, surprisingly, the possibility to improve the efficiency of the device despite a reduction in the base surface which is available for receiving thereon the LED chips. By the arrangement of the LED chips on the rear surface, the light guide is disposed in direct neighboring relationship thereto and the light can be irradiated thereunto by the LED chips. The cooling body preferably expands from the rear surface outwardly towards its other end so that the mass and surface available for heat transfer is, in comparison to the cross-section of the rear surface, drastically enlarged. In accordance with the present invention, it is particularly advantageous that, through the arrangement of the LED-chips on the rear surface xe2x80x94that is, immediately neighboring the light guide xe2x80x94there is not a need to provide reflective surfaces. In the known approaches in which the LED chips are mounted on the cooling body, the light is, to a large extent, conducted onto reflective surfaces, is reflected thereby, and, after varying multiple further reflections, eventually is guided to the light guide. Evaluations in connection with the understanding of the conventional approaches have shown that the reflecting activity not only reduces the light efficiency, but also increases considerably the heat or warmth which is generated and which must then necessarily be transferred or guided away.
In accordance with the present invention, it is provided, in contrast, to directly irradiate the light guide in a reflection free manner. The heat shed or given off by the LED chips is at the same time also emitted onto the light guide so that, in accordance with the present invention, the heat radiation can be deployed for polymerizable masses as well.
In accordance with the present invention, it is provided that the multiple LED arrangement gives off heat in the manner of a xe2x80x9chotter markxe2x80x9d approach to the light hardening apparatus. Through the distribution of heat over the relatively large surface area of the conically shaped cooling body, it is ensured that the light hardening device of the present invention is, in total, not heated too severely.
Additionally, the light hardening device of the present invention, in offering a particularly high light output, makes possible a rapid true hardening of the hardenable mass. The hardening time can be reduced, for example in contrast to that of a hand deployable halogen glow lamp, by one-half. By means of the shortened hardening time, the heat capacity of the cooling body also plays a role, on the other hand, to effect a reduction in the temperature level. This means, in practical use, that during the hardening time the increase in temperature exteriorly of the light hardening device is not noticeable and that the cooling apparatus undertakes, as well, a cooling function following the conclusion of the hardening process so that the temperature, when regarded over time, is graduated or smoothed.
In accordance with the present invention, it is nonetheless particularly advantageous that the LED arrangement in combination with the cooling body can be deployed, as well, in substitution for the reflecting halogen glow lamp of a hand deployed light hardening device. The device of the present invention permits a substantial increase in the light performance or output and the life or length of operation of the device and, thereby, as well, the reliability of the light hardening device is automatically increased. It is now possible to avoid the heretofore problematic hardening process which could be interrupted by the burning through of a glow lamp creating a situation in which patients having a partially hardened filling or the like have had to wait. Heretofore, in order to avoid such unfavorable situations in which a further hardening of a partially hardened filling or other dental restoration piece is no longer possible, it has been necessary to deploy two light hardening devices in the dental practice so that, in the event of a failure of the first light hardening device or the reaching of the end of its operational availability, the second light hardening device could be deployed. In accordance with the present invention, the need to deploy two light hardening devices is now eliminated in that the LED arrangement has a drastically increased life cycle and a complete failure or falling out is, in practice, completely foreclosed. The reason for this lies in the fact that the multiple arrangement of LED chips ensures that if a single chip falls out or fails, the light output or performance is reduced by, for example, 5% and this reduction in light output can be compensated for by an increased hardening time.
It is to be understood that the number of LED chips can be accommodated to a wide range of requirements. In connection with round socket elements for the light guide rod, an arrangement of 5xc3x975 LED chips, for example, can be specified so that, in total, 25 chips are available or the corners chips can be omitted so that in total 21 chips are available. Preferably, the chips are arranged in the closest possible arrangement with one another and in immediate neighboring proximity to the entry of the light guide rod.
In accordance with the present invention, it is particularly advantageous that commercially available light guide devices need no further modification to be deployed as a light hardening apparatus or device in connection with the present invention, or to be provided with the light source of the present invention in substitution for the reflecting halogen glow lamp. In this manner, the cooling body preferably includes two electric contact rods or plug elements on its back end which correspond to the contact rods of a halogen glow lamp. The cooling process follows in the manner of a conventional halogen glow lamp cooling process by contact with the ribbed element bodies which encircle the halogen glow lamp. Preferably, the two ribbed element bodies are so firmly connected to one another as to ensure a secure arrangement so that the shedding or conducting away of the heat or warmth is assured.
Additionally, if a water cooling arrangement of the ribbed element bodies is to be factored in, so that the ribs are arranged in an overlapping aligned manner, it is preferable that an air cooling arrangement with a forced air element is provided which can thus lead to weight saving advantages.
It is additionally particularly advantageous that the temperature management of a commercially available light hardening device can be further used without modification. Typically, a forced air element or component is actuated as soon as the temperature exceeds a predetermined threshold value. Due to the improved working efficiency of the light source of the present invention, a reduced heat or thermal buildup occurs so that there is a corresponding prolongation of the time until the forced air element must be actuated.
The light hardening device and light source of the present invention are suitable as well for main voltage supply as well as for supply by means of a battery. Due to the substantially high working efficiency of the device for the light source, the life of the battery is extended.
In accordance with the present invention, it is particularly advantageous if the LED arrangement of chips is comprised of at least two different types of chips whose emission maximum are at different wave lengths. In this connection, the particular features of a two catalyzer system can be taken into account.
In an advantageous embodiment of the light hardening device of the present invention, it is further provided that the cooling body is configured in a hollow fashion and a control device is disposed in the interior of the cooling device for receiving thereon the LED chips. By a corresponding modification of the software or, alternatively, the hardware, of a hand device, it is also possible to sequentially actuate the two LED chip portions even if only two energy supply contacts are provided. In this connection, an impulse control can, for example, be provided, which is integrated with the control device disposed in the cooling body.
It is to be understood that any suitable desired modifications of the light hardening device or light source of the present invention are possible without going beyond the scope of the present invention. Thus, the cooling body can, as needed, also be configured as the base cooling body which can be connectable via corresponding adapters with the ribbed element bodies to ensure a good conducting away of the heat. It is also possible to improve the resistance to heat transfer between the cooling body and the ribbed element body by insertion of a conventional heat conducting paste.

Light hardening device and a light source suitable for use in a light hardening device


The present invention provides methods and apparatus to detect and reliably record the physical history of a product including effects due to one or more of the following: 1) product use 2) handling 3) tampering and 4) environment of the product (as changes in the environment, such as excessive temperatures, humidity, or shocks, can result in degradation to a product). The apparatus includes a xe2x80x9csmart cardxe2x80x9d, or, more generally, xe2x80x9csmart tokenxe2x80x9d, in combination with one or more sensors which record the external influences on the product and/or the environment and records those changes in an encrypted form. This information can then be verified by any individual who is equipped with a (possibly public) decryption key, but capability to modify this information, depending on the application, is restricted to those with access to the encrypting key. Furthermore, the apparatus contains authentication information which can be reliably verified, in particular to confirm that the apparatus is attached to the product it supposed to be attached to.

1. Field of the Invention
The present invention generally relates to security of consumer goods and, more particularly, to the use of smart tags in maintaining product security.
2. Background Description
There is a need for certain products to be equipped with some apparatus which can provide information about the current state of the product as a result of events the product was subjected to prior to becoming in the possession of a potential consumer. Examples include the state of medical or food products prior to their being used by a consumer.
Also, consumers sometimes have the right and/or the need to know whether a product is brand new or not. This is especially true of expensive items. There is also a need for a product to be equipped by some apparatus which can record some aspects of the product history, for example in the case of automobiles where today odometers indicate, not very securely, one aspect of the history of the automobile.
Another context for the invention is the fact that, in some cases, the containers of some products are reused by the manufacturer, and the consumer would like to know if the product in the container is new or not, and if the container has been reused by a third, unauthorized, party. There is also a need for a method to detect whether the product has deteriorated, either because of defects, or because its expiration date has passed, or because of unwanted change in the environment, for instance in the form of excessive cold, heat or humidity. These scenarios require an apparatus which can detect the physical forces a product was subjected to as a result of use, handling, tampering or environmental factors. For either human intervention or environmental factors, it may be important in some circumstances that the recorded history of such events be very difficult to modify or counterfeit.
The prior art contains many methods involving seals and enclosures which allow one to detect when a package has been tampered with. Such prior art go way back in history, and a multitude of improvements, with very general or very specific uses, have been proposed which benefit from the general progress of technology. For example, U.S. Pat. No. 5,159,629 to Glen P. Double and Steve H. Weingart describes an intrusion barrier for protecting an electronic assembly from tampering. The prior art also contains methods of recording chronological information such as a data logger which stores information on a product as described in U.S. Pat. No. 5,010,560 to Mark A. Janney, Roger Newey, and Irwin J. Robinson.
However, these methods do not overcome the problem of providing a tamper evident history of a product and/or of its environment. The prior art does not allow the information about the history of a product and/or of its environment to be securely recorded and kept.
It is therefore an object of the present invention to provide a novel improvement on the prior art of tamper evident packaging which can detect when a product has been tampered with and resists the efforts of a tamperer, or anyone else who would benefit from hiding the tampering, or to hide the signs of tampering.
In the following, terms such as xe2x80x9cimpossible to changexe2x80x9d or xe2x80x9ctamper-proofxe2x80x9d should be understood to describe situations in which sufficient resistance to tampering is provided to make successful attacks rare due to cost/benefit issues, since codes, etc., can theoretically be broken if sufficient resources are brought to bear on the attack.
The invention uses a smart card, as described in U.S. Pat. Nos. 3,971,916, 4,007,355, 4,092,524, and 4,102,493 to Roland Moreno, or, more generally, a smart token, in combination with sensors attached to the product and/or to the smart card: upon tampering, or as a response to other circumstances, the sensors generate signals which are encrypted and recorded in the memory or storage device of the smart card attached to the product.
Recall that, for example, by using a zero-knowledge protocol, a smart card can be authenticated but cannot be duplicated. This technology has been disclosed for instance in U.S. Pat. No. 5,140,634 to Guillou, et al. This is the property which characterizes a smart card. Accordingly, in the rest of the present disclosure, any electronic component with these properties and which has some memories and/or some processing capabilities, will be called xe2x80x9ca smart tokenxe2x80x9d or xe2x80x9ca smart cardxe2x80x9d, even if it does not actually take any form resembling a card. A general reference to smart card technology and applications can be found in Smart Cards: A Guide to Building and Managing Smart Card Applications, by Henry Dreifus and J. Thomas Monk, John Wiley and Sons, 1998.
When the product or its packaging is tampered with, some attribute of the product or its environment changes. This change is what is detected by (at least some of) the sensors attached to a smart card, and the smart card will record this change irreversibly by erasing or writing some information within the smart card memory. The smart card also can be made duplication resistant by using a zero-knowledge protocol so that only the manufacturer of the original product, and/or possibly a trusted third party, for example, can produce or buy such smart cards. The smart card also can record the history of these changes in its internal memory.

Method and apparatus for securely determining aspects of the history of a good

International Business Machines Corporation


A system for monitoring and/or controlling tissue modification during an electrosurgical procedure includes an electrosurgical apparatus connected to an electrosurgical generator and configured to grasp tissue therebetween via a pair of jaw members. The system also includes an optical system having an optical source that directs light through tissue. One or more optical detectors analyze the light transmitted through and reflected back from the tissue and a processor utilizes this information to control the delivery of electrosurgical energy from the electrosurgical generator to the tissue.

1. Technical Field
The following disclosure relates to a system and method for monitoring macroscopic tissue modifications during an electrosurgical procedure, and more particularly to a system and method that quantifies the progress of tissue thermal damage and dehydration using optical monitoring.
2. Description of Related Art
Electrosurgical forceps use a combination of mechanical pressure and electrical energy to effect hemostasis, by heating tissue and blood vessels to coagulate, cauterize and/or seal tissue. By controlling the power, frequency and duration of the electrical energy delivered to the tissue, a surgeon can cauterise, coagulate, desiccate and/or slow bleeding. However, the delivered energy must be controlled in real-time as a function of the tissue state so that a reliable and reproducible surgical effect is generated.
To resolve the issues above and other issues relevant to coagulation and other tissue treatments, Valleylab Inc. (a division of Tyco Healthcare LP) has developed a technology called vessel or tissue sealing. Electrosurgical vessel sealing is fundamentally different from the process of coagulating vessels. For the purposes herein, "coagulation" is defined as a process of desiccating tissue wherein the tissue cells are ruptured and dried. Vessel sealing is defined as a process of liquefying collagen in tissue, so that it forms a fused mass with limited demarcation and capable of joining opposing tissue structures to seal a large vessel.
It is known in the art that the radio frequency (RF) energy delivery, the distance between jaw members in the sealing device and the pressure exerted by the jaw members must be controlled. In this way, the optimum tissue transformations leading to a seal can be generated, and hence a reproducible reliable seal can be achieved.
Two macroscopic effects that are induced in tissue during the RF tissue fusion process are thermal damage and dehydration. For the purposes herein, the term "thermal damage" is used to describe any bio-structural alteration of the tissue induced by heat. Thermal damage generally includes several biophysical modifications of the tissue that can ultimately lead to tissue death or denaturation—the loss of tridimensional protein structure.
The energy delivered to the tissue during an electrosurgical procedure and the consequent tissue transformations must be controlled and terminated so that a reliable seal is achieved. Historically, it was the responsibility of the surgeon to control and terminate the delivery of energy when the desired effect was produced. The experience of the surgeon was therefore of paramount importance. In the late 1980s, feedback controlled energy sources were introduced, in an effort to eliminate the need for empirical operation. For example, modifications to the tissue electrical impedance have been used as a feedback parameter in RF tissue fusion. Similarly, modifications to the optical properties of the tissue have been suggested to measure transformations induced by laser processing. Each of these methods has some drawbacks.
For example, impedance is often used to control the delivery of RF energy during tissue fusion, because it is relatively easy to measure and because dehydration is believed to reduce conductivity and, hence, increase impedance during the final stage of the fusion process. However, hydration does not completely correlate to impedance. As a result, impedance tends to be a less useful control parameter for the overall tissue sealing process.
Optical spectroscopy has the potential to provide more detailed information on the overall state of the tissue, since it allows information to be gathered on both the tissue structure and the tissue's biochemical makeup. In this case, there are much more significant meteorological challenges, since the detectable signals are generally very weak. Further, algorithms are typically required to extract directly relevant information about the tissue-state from the raw optical signals.
Various prior art patents have proposed the use of optical measurements to control the delivery of energy during an electrosurgical procedure, e.g., U.S. Pat. Nos. 5,762,609; 5,769,791; 5,772,597; and 5,785,658 to Benaron. These references disclose that signals can be measured either at or inside the surface of the tissue and that spectroscopy may be utilized in transmission or in reflection to monitor the signal. However, experiments show that the very large changes in scattering that occur in tissue can cause the signal detected by either method to be effectively extinguished during different stages of a thermal process, so that neither method on its own can provide continuous feedback. The systems proposed by Benaron also use raw optical parameters to control the electrosurgical generator, rather than extracted parameters such as thermal damage and tissue hydration.

Method and system for monitoring tissue during an electrosurgical procedure


A method of optical bi-direction communication between mobile communication devices, wherein each mobile communication device has data storage locations, and wherein the mobile communication device includes an optical data capture mechanism, includes rendering, in one mobile communication device, data in a computer readable form; determining if the rendered data can be stored in a single data file; converting the rendered data to a graphic representation; and reading and storing the graphic representation with the optical capture mechanism of another mobile communication device.

U.S. Patent Publication No. 20020071067, of Yoshitoshi, for Blacklight and; liquid crystal display apparatus using the same, published Jun. 13, 2002, discloses a scannable barcode display and methods for using the same, however, the reference does not disclose the use of a CCD camera as a dual use device on a cell phone, nor does it provide for the use of scanned data as intrinsic to the use and function of the cell phone.
U.S. Patent Publication No. 20010051915, of Ueno et al., for Data transfer system using mobile terminal and two-dimensional barcode, published Dec. 13, 2001, discloses a data transfer system using a mobile terminal and a two-dimensional barcode, and more particularly, a processing system, server, processing terminal, and communications terminal that can be used to pay for purchases and manage membership cards and admission tickets, and other services, however, the reference does not disclose the use of a CCD camera as a dual use device on a cell phone, nor does it provide for the use of scanned data as intrinsic to the use and function of the cell phone.
WO0227593, of Shin et al., for integrated customer management system and method using wireless barcode, priority date Sep. 29, 2000, discloses an invention that relates to a customer management system and method using LCD barcode displayed on mobile terminal, however, the reference does not disclose the use of a CCD camera as a dual use device on a cell phone, nor does it provide for the use of scanned data as intrinsic to the use and function of the cell phone.
EP0537522, of Fernböck, for Apparatus and method for collecting, possibly processing, storing and transmitting all kinds of data, priority date Apr. 21, 1993, describes an apparatus and method for collecting and manipulation data, wherein the collection terminal is housed in a unitary structure, however, the reference does not disclose the use of a CCD camera as a dual use device on a cell phone, nor does it provide for the use of scanned data as intrinsic to the use and function of the cell phone.
WO0157811, of Doherty et al., for Data Handling, priority date Feb. 2, 2000, describes a data handling device in the form of a mobile phone and a scanner of some unspecified type, including a RF connection between phone and mobile system which provides the ability to store scanned data at phone and forward to mobile system, however, the reference does not disclose the use of a CCD camera as a dual use device on a cell phone, nor does it provide for the use of scanned data as intrinsic to the use and function of the cell phone.
U.S. Patent Publication No. 20010044324 of Carayiannic et al., for Cellular Telephone, filed Dec. 8, 2000, describes a cell phone inputting an encoded business card, but does not disclose phone-to-phone information exchange.
U.S. Pat. No. 6,412,689, to Horiguchi et al., for Communication equipment and method for business card information interchange, granted Jul. 2, 2002, describes a capture mechanism, however, the reference does not disclose the use of graphical patterns for exchanging information optically.
U.S. Pat. No. 6,311,214, to Rhoads, for Linking of computers based on optical sensing of digital data, granted Oct. 30, 2001, describes a system wherein a printed object is encoded with plural-bit data. When such an object is presented to an optical sensor, the plural-bit data is decoded and used to establish a link to an internet address corresponding to that object, however, the reference does not disclose phone-to-phone information exchange.
U.S. Pat. No. 6,041,374, to Postman et al., for PCMCIA interface card for coupling input devices such as barcode scanning engines to personal digital assistants and palmtop computers, granted Mar. 21, 2000, describes the provision of a scanning mechanism which may be linked to a PDA or computer.

Method for transferring data objects between portable devices


Provided is a method and apparatus for measuring evaporative vehicle emissions in a fixed-volume/variable temperature test chamber. The method comprises the steps of providing a volume compensation device in fluid communication with a test chamber for compensating for changes in the test chamber fluid volume, determining the density of the evaporative emissions and the test chamber fluid in mass per unit volume at selected sample times t.sub.n, where n is a positive integer, measuring the temperature of the test chamber fluid at the sample times t.sub.n, measuring the absolute fluid pressure of fluid at the sample times t.sub.n, determining the difference in the test chamber fluid volume between successive sample times t.sub.n, determining the mass of the evaporative emissions in lost volume and mass measurements and summing the determined masses of the evaporative emissions to provide a calculation of the evaporative emissions lost by the volume compensation device during expansion of the test chamber fluid and summing this with the final sample to determine the total evaporative emissions from a vehicle. In an alternative embodiment, a plurality of impingers are also provided for use in determining the lost mass of alcohol emissions in flexible fueled vehicles.

As used in the art, the acronym "SHED" generally refers to sealed housings for evaporative determination. These SHEDS are generally rectangular enclosures which define fluid-fillable test chambers adapted to measure evaporative emissions such as hydrocarbon from automobiles, trucks and other motor vehicles. Historically, such testing was performed while the test chamber fluid (typically air) was maintained at a constant temperature. In operation, the test vehicle was placed in the SHED with the engine and all other equipment turned off. The door to the SHED was then closed and sealed. Thereafter, selected emissions such as hydrocarbon (HC) were measured at the beginning and end of a fixed timed period which was generally one hour. The SHED test is one step of the federal test procedure which is described in the Federal Register, subpart B, 86,101 to 86.145-82.
Those skilled in the art will recognize that recent proposed regulations developed for the Clean Air Act have revised the evaporative portion of the federal test procedure. As revised, the evaporative portion now requires the use of a variable-volume/variable-temperature test chamber. As more thoroughly described in a draft Evaporative Regulations OMB1 of Nov. 18, 1992, Sec. 86,078-3 to 86.098-10, new SHEDS must therefore define fluid-fillable test chambers capable of changing fluid temperature following prescribed fluid temperature profiles.
It should be noted that sealing technology, which was not a significant issue under the prior art constant temperature systems, has now become a complex problem for SHED designers under the variable temperature requirements. As those skilled in the art will recognize, by design, conventional SHEDs must include a plurality of penetrations for sample ports and temperature probes; as well as a vehicle entrance/exit door, an operator egress door and a purge vent. All of these doors and penetrations must be sufficiently sealed or leakage will occur and emission sample will be lost. Because of the new variable temperature requirements and the need for a sealed housing to prevent loss of emissions, the corresponding volume compensation requirement was introduced to avoid pressurizing the SHED.
To comply with the new volume compensation requirements, conventional SHEDs have incorporated various volume control devices for varying the volume of the fluid-fillable test chambers during expansion and contraction of test chamber fluid. Typically, such devices have been provided in fluid communication with the fluid (typically air) outside of the test chamber and are controlled by pure pressure feedback systems through the use of differential pressure transducers. Typical volume compensation devices include, for example, a plurality of inflatable bags which are disposed on the internal walls of the test chamber. During expansion of the test chamber fluid, the bags are deflated to increase the volume of the test chamber. Similarly, during contraction cycles, the bags are inflated to decrease the volume of the test chamber. It should be noted, however, that because these devices use differential pressure transducers as feedback, a near-perfect seal is required for the SHED to operate properly. Indeed, induced pressure variations, however slight, will bias the differential pressure transducer and cause an error in the amount of volume compensation. The resulting error will be magnified by forcing the sample out of the SHED or diluting the sample by drawing fluid into the SHED. Because truly "sealed" housings are nearly impossible to achieve, the pressure control systems of the prior art have proven unreliable and thus highly susceptible to error.
As those skilled in the art will recognize, the need for perfect sealing arises only because of the fear of emission sample Loss. Thus, if a control system could be designed to precisely calculate emission loss, a fixed-volume test chamber could be utilized and SHED pressurization could be obviated by merely providing or evacuating fluid directly from the SHED test chamber.

Method and apparatus for measuring evaporative vehicle emissions in a fixed-volume/variable temperature test chamber