A system for extraction of volatiles from bodies in a vacuum. The volatile containing solid may be subsurface heated with microwave or RF energy subliming volatiles that are captured with a containment structure that directs the flow of the volatile through a cold trap for collecting and condensing the volatile. In one variation, a sample, or an entire body may be enveloped in a sealed container for extraction of volatiles that are then collected and condensed. In a further variation, a planetary surface area is covered and the perimeter sealed at the surface. The area is then heated from above to release volatiles that are then collected and condensed. To heat layers below the surface that contain high concentrations of volatiles, a hollow auger can gain access to the subsurface volatile and microwave or RF energy can be delivered down the hollow auger with a coax cable and vapor can escape through the hollow auger to a capture apparatus.

Mining of planetary bodies may be possible and beneficial to mankind. Mining of planetary bodies is the process of extracting raw materials from the planetary bodies while in space. In this regard, planetary bodies, such as, for example, asteroids and/or minor planets are often rich in raw materials. For example, planetary bodies may comprise one of or combinations of regolith, rocks, water, methane, carbon dioxide, and other volatiles, as well as many other types of resources.
Mining of planetary bodies may be beneficial for a number of reasons. For example, the mined resources may be used for space construction, sustainment of astronauts on site, radiation protection shielding, and rocket propellant. This reduces the mass of resources that must be launched from Earth. Using resources gathered during space exploration is oftentimes referred to as in-situ resource utilization.

System for extraction of volatiles from planetary bodies using microwave and RF processes


An improved paper clip consisting of a wire clip integrally wrapped within a folded semi rigid banding allowing for the display of printed advertising, promotional, marketing, messaging or decorative indicia, in a multitude of shape and size, as suits the material displayed, while being easier to apply, and remove, while providing protection to the papers to which it is attached from crushing and tearing.

1. Field of Invention
This invention relates to paper clips, and more particularly, an improved paper clip device that integrally incorporates the ability to display indicia in a plurality of size and shape as best suits the indicia displayed while improving the overall functionality of the paper clip in general.
2. Description of Prior Art
Paper clips in a myriad of constructions are known in the prior art. In its most ubiquitous form, the clip is a wire device formed of inter-nesting elongate wire loops. The prior art shows numerous devices that attempt to incorporate the ability to display indicia.
All previous attempts at including indicia in a clipping device have been awkward contrivances falling into two categories: adding an element to an existing clip design or a new clip design. Both approaches include some limited flat planar surface upon which limited indicia could be printed by limited printing production means.
All the prior art fails to achieve a format allowing flexibility of size, shape, and material so as to allow any indicia to be displayed to its best advantage. None of the prior art utilizes the standard wire clip in a manner that improves the functionality of the clip while providing the ability to display indicia attractively. None of the prior art has achieved any acceptance in the market place being either too expensive to produce or too awkward a contrivance to find widespread acceptance.
While all of the prior art allows the adequate retention of a various number of pages, none attempt the combined features of providing for the inclusion of promotional indicia in a multitude of shape and size as best suits the indicia displayed, enhance the ease of application, and removal as a clipping device, while protecting the clipped sheets from indentation from crushing or marring, and can be assembled either by hand or machine, while being economical to produce.
As in U.S. Pat. No. 4,286,358 to Levin, 1981 Sep., 1, or in part as in U.S. Pat. No. 4,951,408 to Banks, 1990Aug. 28, and other similar prior art, a separate manufactured element is either affixed to or added onto the standard paper clip as an added element. In U.S. Pat. No. 5,398,384 to Rinard, 1995 Mar. 21, and other similar prior art, the attempt is manifested as a new paper clip design and configuration.
None of the prior art provides the flexibility, economy and ease of use of the present invention. No prior art has the flexibility to display indicia in a variety of size and shape. None of the prior art utilizes a wire paper clip in combination with an integrally wrapped band utilizing the characteristics of the wire paper clip to improve the functionality of the combination. None of the prior art is able to provide the means for a variety of size, shape, and material, so that any given end user can have indicia incorporated that is consistent with what they are utilizing in other printed media.


A grating surface of a diffraction grating diffracts a laser beam emitted from a semiconductor laser device in xc2x11st order directions. The grating surface is formed in a rectangular or elliptic shape in such dimensions that a light spot formed on an objective lens by xc2x11st order diffracted beams is located in an aperture of the objective lens and not displaced from the aperture even if the objective lens is horizontally moved in a tracking operation. A grating surface of another diffraction grating has a width smaller than the width of an overlap region of a light spot on the diffraction grating corresponding to a part of a beam, diffracted in the xc2x11st direction, entering an objective lens and a light spot on the diffraction grating corresponding to a part of a beam, diffracted in the xe2x88x921st direction, entering the objective lens.

1. Field of the Invention
The present invention relates to an optical pickup apparatus and an optical recording medium drive employing the same.
2. Description of the Prior Art
An optical pickup apparatus employed for an optical recording medium drive such as an optical disk drive is adapted to record or read information in or from an optical recording medium such as an optical disk or detect a servo signal with a laser beam.
FIG. 20 schematically illustrates a conventional optical pickup apparatus disclosed in Japanese Patent Laying-Open Gazette No. 3-76035 (1991). This optical pickup apparatus performs tracking servo control by the three-beam method.
Referring to FIG. 20, symbols X, Y and Z denote the radial direction of an optical disk 1, the track direction of the optical disk 1, and a direction perpendicular to the disk plane of the optical disk 1 respectively.
A semiconductor laser device 102 emits a laser beam B in the direction Z. The beam B emitted from the semiconductor laser device 102 enters a diffraction grating 103. FIG. 21 is a plan view of the diffraction grating 103. The diffraction grating 103 has a grating surface 103a formed by unevenness of regular pitches. The grating surface 103a divides the incident laser beam B into three beams, i.e., a 0th order diffracted beam (main beam), a +1st order diffracted beam (subbeam) and a xe2x88x921st order diffracted beam (subbeam), and transmits the same through a transmission-type holographic optical element 104.
Referring to FIG. 20, an objective lens 105 condenses the three beams transmitted through the transmission-type holographic optical element 104 on the optical disk 1. FIG. 22 is a model diagram showing the condensed states on the recording plane of the optical disk 1. As shown in FIG. 22, the 0th order diffracted beam is condensed on a track surface TR of the recording plane as a main spot M0, and the xc2x11st order diffracted beams are condensed on both sides of the main spot MO as subspots S1 and S2 respectively.
The transmission-type holographic optical element 104 diffracts three returned beams (reflected beams) from the main spot MO and the subspots S1 and S2 in a plane substantially including the directions X and Z, so that a photodetector 106 detects these returned beams.
FIG. 23 is a typical plan view showing an exemplary photodetector 106. This photodetector 106 includes a photodetection part 106a provided on the central portion for performing focus servo control with the astigmatism method and photodetection parts 106b and 106c provided on both sides of the photodetection part 106a for performing tracking servo control with the three-beam method. The returned beam corresponding to the main spot M0 enters the central portion of the photodetection part 106a while the returned beams corresponding to the subspots S1 and S2 enter the photodetection parts 106b and 106c respectively.
The aforementioned optical pickup apparatus performs tracking control in the following manner: As shown in FIG. 22, the track surface TR recording information is different in light reflectance from a non-track surface. When the photodetection parts 106b and 106c detect the returned beams from the subspots S1 and S2, the returned beams from the two subspots S1 and S2 entering the two photodetection parts 106b and 106c are equal in light intensity to each other if the main spot MO excellently tracks the track surface TR to be reproduced. If the main spot MO deviates to either side of the track surface TR, on the other hand, the photodetection part 106a or 106b relatively largely detects the light intensity of the returned beam from one of the subspots S1 and S2. With output signals E and F from the photodetection parts 106b and 106c, therefore, the following tracking error signal TE is obtained:
xe2x80x83TE=Exe2x88x92F
The optical pickup apparatus performs excellent tracking control when the tracking error signal TE is zero, and detects deterioration of the tracking state as the value of the tracking error signal TE increases.
When detecting the tracking error signal TE, the optical pickup apparatus moves the objective lens 105 in the radial direction (the direction X), for correcting the condensed positions of the main spot M0 and the subspots S1 and S2 on the track surface TR of the optical disk 1.
FIG. 24A is a typical sectional view showing the condensed states of diffracted beams B1 and B2 diffracted by the diffraction grating 103, and FIG. 24B shows typical plan views of the objective lens 105. As shown in FIG. 24A, the diffracted beam B1 diffracted by the diffraction grating 103 in the +1st order direction passes through the objective lens 105, to be condensed as the subspot S1. The diffracted beam B2 diffracted in the xe2x88x921st order direction passes through the objective lens 105, to be condensed as the subspot S2.
Referring to FIG. 24B, the grating surface 103a of the diffraction grating 103 is formed to be larger than the laser beam B, as shown in FIG. 20. Therefore, the laser beam B incident on the grating surface 103a is diffracted over a region wider than an aperture 105a of the objective lens 105, to result in regions B1a and B2a not entering the aperture 105a of the objective lens 105.
When the optical pickup apparatus performs a tracking operation in this state and moves the objective lens 105 in the direction X (the radial direction of the optical disk 1), the incident states of the diffracted beams B1 and B2 on the objective lens 105 change from those on the left to those on the right in FIG. 24B. The ratios of the diffracted beams B1 and B2 entering the aperture 105a of the objective lens 105 reduce following movement of the objective lens 105. Therefore, the light quantities of the subspots S1 and S2 reduce on the recording plane 1a of the optical disk 1, to result in reduction of the light quantities of the returned beams from the subspots S1 and S2 entering the photodetection parts 106b and 106c. When the objective lens 105 is moved during the tracking operation, therefore, the output of the tracking error signal TE disadvantageously reduces.
FIG. 25 is a model diagram for illustrating the diffracted state of the beam B diffracted by the diffraction grating 105. Referring to FIG. 25, a light source 200 forms an emissive end of the semiconductor laser device 102, so that the laser beam B emitted from this light source 200 is condensed on the recording plane 1a of the optical disk 1 as the two subspots S1 and S2. The transmission-type holographic optical element 104 is omitted in FIG. 25.
The grating surface 103a diffracts the laser beam B emitted from the light source 200 at least in the +1st order direction and the xe2x88x921st order direction. In the laser beam B, the +1st order diffracted partial beam of a partial beam BE1 passes through the objective lens 105, to be condensed as the subspot S1. The +1st order diffracted partial beam of a partial beam BE2 passes through a part beyond the objective lens 105, not to be condensed on the subspot S1.
On the other hand, the xe2x88x921st order diffracted partial beam of a partial beam BE3 passes through the objective lens 105, to be condensed on the subspot S2. Further, the xe2x88x921st order diffracted partial beam of a partial beam BE4 passes through a part beyond the objective lens 105, not to be condensed on the subspot S2.
When an optical axis LP passing through the peak of the light intensity distribution of the laser beam B aligns with a central axis Z0 passing through the center of the objective lens 105, the light quantities of the partial beams BE1 and BE3 condensed on the subspots S1 and S2 respectively are equal to each other. Therefore, the correct tracking state can be detected by detecting the difference between the light quantities of the returned beams from the two subspots S1 and S2.
However, the optical axis LP of the laser beam B may deviate from the central axis Z0 of the objective lens 105 due to a locational error of the semiconductor laser device 102 or the emission property of the laser beam B. When the optical axis LP deviates from the central axis Z0, the partial beams BE1 and BE3 are condensed on the two subspots S1 and S2 in non-uniform light quantities.
FIGS. 26A and 26B illustrate light intensity distribution states of the laser beam B in a section taken along the line Qxe2x80x94Q in FIG. 25. In FIGS. 26A and 26B, a symbol 2R denotes the diameter of the partial beam incidenting into the objective lens 105 within the +1st and the xe2x88x921st order diffracted beams. The optical axis LP aligns with the central axis Z0 in FIG. 26A, while the former deviates from the latter in FIG. 26B. FIG. 26A shows the light quantities corresponding to the partial beams BE1 and BE2 in regions (E1+E2) and (E3) respectively. Further, the light quantities corresponding to the partial beams BE3 and BE4 are shown in regions (E1+E3) and (E2) respectively.
As shown in FIG. 26A, the light quantity (the region (E1+E2)) of the partial beam BE1 condensed on the subspot S1 is equal to the light quantity (the region (E1+E3)) of the partial beam BE3 condensed on the subspot S2 when the optical axis LP aligns with the central axis Z0.
When the optical axis LP deviates from the central axis Z0, on the other hand, the light quantities of the partial beams BE1 and BE3 condensed on the subspots S1 and S2, which are shown in regions (E1+E20) and (E1+E30) respectively, differ from each other. Thus, the tracking error signal TES based on the returned beams from the two subspots S1 and S2 is so offset that it is difficult to detect the correct tracking state.
FIG. 27 schematically illustrates another conventional optical pickup apparatus. This optical pickup apparatus is adapted to perform tracking servo control and focus servo control with the three-beam method and the astigmatism method respectively.
Referring to FIG. 27, a laser beam 112 emitted from a semiconductor laser device 121 passes through a transmission-type diffraction grating 123 to be divided into three beams, i.e., a 0th order diffracted beam (main beam) and xc2x11st order diffracted beams (subbeams) and transmitted through a transmission-type holographic optical element 124.
An objective lens 116 condenses the three beams transmitted through the transmission-type holographic optical element 124 on an optical disk 1 as a main spot M0 and subspots S1 and S2 located on both sides thereof. An actuator 140 supports the objective lens 116 to be movable in the radial direction (the X-axis direction) of the optical disk 1 for a tracking operation and to be movable in the Y-axis direction for a focus operation.
FIG. 28 illustrates the main spot M0 and the subspots S1 and S2 formed on the optical disk 1. As shown in FIG. 28, the optical system of the optical pickup apparatus is so adjusted that the main spot M0 scans a track TR to be reproduced and the subspots S1 and S2 scan both sides of the main spot M0 slightly over the track TR.
The transmission-type holographic optical element 124 diffracts three returned beams (reflected beams) from the optical disk 1, so that a signal detection photodiode 133 detects the same.
FIG. 29 is a typical plan view showing an exemplary signal detection photodiode 133. This signal detection photodiode 133 includes photodetection parts 150a to 150d provided on the central portion for performing focus servo control with the astigmatism method and photodetection parts 150e and 150f provided on both sides of the photodetection parts 150a to 150d for performing tracking servo control with the three-beam method. The returned beam (main beam) corresponding to the main spot M0 enters the central portion of the photodetection parts 150a to 150d, while returned beams (subspots) 112a and 112b corresponding to the subspots S1 and S2 enter the photodetection parts 150e and 150f respectively.
On the basis of detection signals E and F from the photodetection parts 150e and 150f of the signal detection photodiode 133 receiving the returned beams (subbeams) 112a and 112b, the optical pickup apparatus performs the tracking operation in the following manner:
FIG. 30 is a circuit diagram showing respective parts of an optical disk drive comprising the optical pickup apparatus 100 performing the tracking operation. Referring to FIG. 30, the photodetection parts 150e and 150f of the signal detection photodiode 133 of the optical pickup apparatus 100 output the detection signals E and F to an E-F processing part 155 provided on a driving circuit part 154 of the optical disk drive. With the detection signals E and F received from the photodetection parts 150e and 150f, the E-F processing part 155 obtains the following tracking error signal TE:
TE=Exe2x88x92F
The tracking error signal TE is inputted in an operational amplifier 158 of a servo circuit 157 through a low-pass filter 156, amplified and thereafter supplied to a tracking coil 142 of the actuator 140 of the optical pickup apparatus 100.
As shown in FIG. 27, the actuator 140 supports the objective lens 116 to be movable in the radial direction (the X-axis direction) of the optical disk 1. The actuator 140 comprises a holder 141 for holding the objective lens 116, the tracking coil 142 connected to the holder 141 to be movable in the radial direction, and a permanent magnet 144 separating from the tracking coil 142. When a driving voltage is applied to the tracking coil 142, the actuator 140 moves the objective lens 116 in the X-axis direction by electromagnetic force caused between the tracking coil 142 and the permanent magnet 144.
When the main spot M0 formed on the optical disk 1 effectively tracks the track TR to be reproduced in FIG. 28, the returned beams 112a and 112b from the two subspots S1 and S2 enter the photodetection parts 150e and 150f in equal light intensity. Therefore, the tracking error signal TE outputted from the E-F processing part 155 is zero and no driving voltage is applied to the tracking coil 142 of the actuator 140. Thus, the objective lens 116 maintains its state.
When the main spot MO deviates to either side of the track TR to be reproduced, on the other hand, the light intensity of the returned beam 112a or 112b from the subspot S1 or S2 increases. Thus, the detection signals E and F from the photodetection parts 150e and 150f differ from each other. Therefore, the E-F processing part 155 outputs the tracking error signal TE, which in turn is amplified by the operational amplifier 158 of the servo circuit 157 so that a driving voltage is applied to the tracking coil 142 and the actuator 140 radially moves the objective lens 116 for correcting the position of the main spot M1.
In recent years, miniaturization of such an optical pickup apparatus 100 is strongly desired, and the respective elements thereof are miniaturized with reduction of the diameter of the objective lens 116. In an assembling step for the optical pickup apparatus 100, therefore, it is difficult to correctly align the objective lens 116 with the optical path of the laser beam 112.
FIG. 31 is a typical plan view showing an incident state of the laser beam 112 on the objective lens 116. In the optical pickup apparatus 100, the semiconductor laser device 121, the diffraction grating 123 and the transmission-type holographic optical element 124 are integrated into a unit independently of the objective lens 116, and these units are assembled with each other in alignment. In assembling, therefore, the optical axis of the objective lens 116 may deviate from those of the two subbeams 112a and 112b of the laser beam 112 by d along the radial direction (the X-axis direction) of the optical disk 1, as shown in FIG. 31.
Such deviation d in the mounting position of the objective lens 116 results in the following disadvantage: The optical disk drive moves the objective lens 116 by a constant distance in the radial direction of the optical disk 1 in order to search the program for a tune recorded in the optical disk 1, for example. If the optical axis of the objective lens 116 deviates from those of the subbeams 112a and 112b of the laser beam 112 by d in assembling as shown in FIG. 31, however, the subbeams 112a and 112b pass through the objective lens 116 in different light quantities following movement of the objective lens 116 for the program search, in response to the direction of movement. The light quantities of the subbeams 112a and 112b passing through the objective lens 116 extremely reduce following movement of the objective lens 116 in one direction, and hence the output of the tracking error signal TE based on the subbeams 112a and 112b passing through the objective lens 116 reduces to hinder a effective tracking operation.
FIG. 32 illustrates changes of the tracking error signal TE following movement of the objective lens 116. Referring to FIG. 32, the horizontal axis shows the direction and the distance of movement of the objective lens 116, and the vertical axis shows the tracking error signal TE. When the center of the objective lens 116 aligns with the optical axis of the laser beam 112 in the radial direction of the optical disk 1, symmetrical distribution TE0 of the tracking error signal TE is obtained following movement of the objective lens 116, as shown by a dotted line in FIG. 32. When the center of the objective lens 116 deviates from the optical axis of the laser beam 112, on the other hand, asymmetrical distribution TE1 of the tracking error signal TE is obtained depending on the direction of movement of the objective lens 116, as shown by a solid line. The tracking error signal TE reduces below an output value A necessary for tracking on a position of movement of the objective lens 116, to hinder correct program search.
In general, therefore, an offset circuit 159 is provided on one input side of the operational amplifier 158 of the servo circuit 157, in order to correct the deviation of the objective lens 116 from the optical axis of the laser beam 112. In the optical pickup apparatus 100 built into the optical disk drive, the offset circuit 159 corrects the deviation of the objective lens 116 as follows:
The offset circuit 159 moves the objective lens 116 along the radial direction toward the center and the outer periphery respectively by prescribed distances of 400 xcexcm, for example, and detects the voltages of the tracking error signal TE. If the center of the objective lens 116 deviates from the optical axis of the laser beam 112, the tracking error signal TE1 exhibits different voltages following movement of the objective lens 116 toward the center and the outer periphery, as shown in FIG. 32. Therefore, the movement origin position (the position of the objective lens 116 performing no tracking operation) is moved for equalizing the voltages of the tracking error signal TE in movement of the objective lens 116 toward the center and the outer periphery.
The resistance value of a variable resistor 160 of the offset circuit 159 is adjusted and a driving voltage is applied to the tracking coil 142 for moving the movement origin position of the objective lens 116 in the radial direction of the optical disk 1. Further, the objective lens 116 is moved from the movement origin position along the radial direction of the optical disk 1 toward the center and the outer periphery by prescribed distances respectively, for detecting the current values of the tracking error signal TE. Adjustment of the variable resistor 160 of the offset circuit 159 is ended when the detected values of the tracking error signal TE are equal to each other in movement toward the center and the outer periphery. Thus, the deviation of the objective lens 116 from the optical axis of the laser beam 112 in the radial direction of the optical disk 1 can be corrected.
However, the optical pickup apparatus 100 may be independently manufactured and put on the market by a manufacturer different from that for the optical disk drive employing the same. In this case, therefore, the manufacturer for the optical disk drive or the like must adjust the deviation of the objective lens 116 of the optical pickup apparatus 100 with complicated assembling and adjusting operations.
An object of the present invention is to provide an optical pickup apparatus causing no output reduction of a tracking signal following movement of an objective lens in a tracking operation and an optical recording medium drive employing the same.
Another object of the present invention is to provide an optical pickup apparatus capable of suppressing offset of a tracking error signal resulting from optical axis deviation of a beam emitted from a light source and an optical recording medium drive employing the same.
Still another object of the present invention is to provide an optical pickup apparatus capable of adjusting the position of an objective lens with respect to the optical axis of a laser beam in manufacturing, an optical recording medium drive comprising the same, and a method of adjusting an optical pickup apparatus.
The optical pickup apparatus according to the present invention comprises a light source for emitting a beam, a first diffraction element having a diffraction surface for diffracting the beam emitted from the light source at least in first and second directions, and an objective lens for irradiating an optical recording medium with beams diffracted by the first diffraction element in the first and second directions respectively. The objective lens is provided to be movable along the radial direction of the optical recording medium for a tracking operation, and the diffraction surface of the first diffraction element is formed in dimensions for locating a light spot formed on the objective lens by the diffracted beams diffracted by the diffraction surface in the first and second directions respectively in an aperture of the objective lens following movement of the objective lens for the tracking operation.
Also when the objective lens is moved for the tracking operation, all diffracted beams pass through the objective lens, to be condensed on the optical recording medium. Therefore, the light quantities of the diffracted beams condensed on the optical recording medium remain unchanged regardless of movement of the objective lens. Thus, it is possible to prevent the output of a tracking error signal from fluctuation resulting from change of the light quantities of the diffracted beams on the optical recording medium resulting from to the tracking operation.
In particular, the diffraction surface of the first diffraction element is preferably formed in a rectangular shape smaller than a light spot formed on the first diffraction element by the beam emitted from the light source in dimensions for locating a rectangular light spot formed on the objective lens by the diffracted beams diffracted by the diffraction surface in the first and second directions respectively following movement of the objective lens in the aperture of the objective lens.
In this case, the rectangular light spot of the diffracted beams enters the aperture of the objective lens regardless of the movement of the objective lens. Therefore, the light quantities of the diffracted beams condensed on the optical recording medium are maintained constant also when the objective lens is moved, whereby the tracking error signal based on the diffracted beams can be prevented from fluctuation.
Particularly assuming that R and Q represent the aperture radius and the amount of movement of the objective lens respectively, L1 and L2 represent effective distances between the light source and the center of the objective lens and between the diffraction surface and the light source respectively, S represents the distance between a first virtual light source supposed to emit a straight beam equivalent to the beam diffracted in the first direction toward the objective lens and the light source or between a second virtual light source supposed to emit a straight beam equivalent to the beam diffracted in the second direction toward the objective lens and the light source, and B1 represents a limit value for the rectangular light spot formed on the objective lens in a direction perpendicular to the direction of movement of the objective lens, the width W1 of the diffraction surface of the first diffraction element in the direction perpendicular to the direction of movement of the objective lens is preferably set to satisfy:
W1 less than 2xc3x97{{square root over (R2xe2x88x92Q2)}xe2x88x92S}xc3x97L2/L1+2S
and the width W2 of the diffraction surface in the direction of movement of the objective lens is preferably set to satisfy:
W2xe2x89xa6{{square root over ((2R)2xe2x88x92(B1)2)}xe2x88x922Q}xc3x97L2/L1
with the following limit value B1:
B1=(W1xe2x88x922S)xc3x97L1/L2+2S
The diffraction surface satisfying the above conditions introduces all diffracted beams diffracted in the first and second directions into the aperture of the objective lens regardless of movement of the objective lens. Thus, the light quantities of the diffracted beams are prevented from variation with movement of the objective lens.
In particular, the optical pickup apparatus provided with the first diffraction element having the diffraction surface formed in a rectangular shape may further comprise a second diffraction element for transmitting the beams diffracted by the first diffraction element in the first and second directions respectively and guiding the same to the objective lens while diffracting returned beams from the optical recording medium, and a photodetector for receiving the returned beams diffracted by the second diffraction element.
In this case, the second diffraction element diffracts the returned beams, so that the returned beams from the optical recording medium can be guided to the photodetector, which in turn detects the tracking error signal.
The diffract ion surface of the first diffraction element is preferably formed in an elliptic or circular shape smaller than the light spot formed on the first diffraction element by the beam emitted from the light source in dimensions for locating an elliptic light spot formed on the objective lens by the diffracted beams diffracted by the diffraction surface in the first and second directions respectively in the aperture of the objective lens following movement of the objective lens.
In this case, all elliptic or circular diffracted beams can be introduced into the aperture of the objective lens regardless of movement of the objective lens in the tracking operation.
Particularly assuming that the elliptic diffraction surface of the first diffraction element has its major axis in the direction perpendicular to the direction of movement of the objective lens, R and Q represent the aperture radius and the amount of movement of the objective lens respectively, L1 and L2 represent effective distances between the light source and the center of the objective lens and between the diffraction surface and the light source respectively, S represents the distance between a first virtual light source supposed to emit a straight beam equivalent to the beam diffracted in the first direction toward the objective lens and the light source or between a second virtual light source supposed to emit a straight beam equivalent to the beam diffracted in the second direction toward the objective lens and the light source, b represents a limit value for the radius of the elliptic light spot formed on the objective lens in the direction perpendicular to the direction of movement of the objective lens and WB represents the width of the elliptic diffraction surface in the direction perpendicular to the direction of movement of the objective lens, the width WA of the elliptic diffraction surface in the direction of movement of the objective lens is preferably set to satisfy:
WAxe2x89xa62xc3x97{{square root over (b2Q2/(b2xe2x88x92R2)+b2)}}xc3x97L2/L1
where
b=(WBxe2x88x922S)xc3x97L1/L2+2S
Further, the width WB of the elliptic diffraction surface of the first diffraction element in the direction perpendicular to the direction of movement of the objective lens is preferably set to satisfy:
2xc3x97[L2/L1xc3x97{{square root over (Rxc3x97(Rxe2x88x92Q))}xe2x88x92S}+S]xe2x89xa6WB less than 2xc3x97[L2/L1xc3x97{{square root over (R2xe2x88x92Q2)}xe2x88x92S}+S]
Assuming that R and Q represent the aperture radius and the amount of movement of the objective lens respectively and L1 and L2 represent effective distances between the light source and the center of the objective lens and between the diffraction surface and the light source respectively, in addition, the width WA of the elliptic diffraction surface in the direction of movement of the objective lens is preferably set to satisfy:
WAxe2x89xa62xc3x97(Rxe2x88x92Q)xc3x97L2/L1
Assuming that S represents the distance between the first virtual light source supposed to emit a straight beam equivalent to the beam diffracted in the first direction toward the objective lens and the light source or between the second virtual light source supposed to emit a straight beam equivalent to the beam diffracted in the second direction toward the objective lens and the light source, further, the width WB of the elliptic diffraction surface of the first diffraction element in the direction perpendicular to the direction of movement of the objective lens is preferably set to satisfy:
WB less than 2xc3x97[L2/L1xc3x97{{square root over (Rxc3x97(Rxe2x88x92Q))}xe2x88x92S}+S]
In particular, the optical pickup apparatus having the first diffraction element having the elliptically formed diffraction surface may further comprise a second diffraction element for transmitting the beams diffracted by the first diffraction element in the first and second directions respectively, guiding the same to the objective lens and diffracting the returned beams from the optical recording medium, and a photodetector for receiving the returned beams diffracted by the second diffraction element.
In this case, the second diffraction element diffracts the returned beams from the optical recording medium for guiding the same to the photodetector, so that the tracking error signal by the photodetector can be detected.
An optical pickup apparatus according to another aspect of the present invention comprises a light source for emitting a beam, a first diffraction element having a diffraction surface for diffracting the beam emitted from the light source at least in first and second directions, and an objective lens for irradiating an optical recording medium with beams diffracted by the first diffraction element in the first and second directions respectively. The width of the first diffraction element in a plane including the optical axis of the beam emitted from the light source and axes of the beams diffracted in the first and second directions respectively is set to be smaller than that of a region including a first light spot and a second light spot. The first light spot is a light spot on the first diffraction element corresponding to a part of the beam, diffracted by the first diffraction element in the first direction, entering the objective lens in the beam emitted from the light source. The second light spot is a light spot on the first diffraction element corresponding to a part of the beam, diffracted by the first diffraction element in the second direction, entering the objective lens in the beam emitted from the light source.
The beam emitted from the light source includes the beam diffracted by the diffraction surface of the first diffraction element only in the first direction to enter the objective lens, a beam diffracted only in the second direction to enter the objective lens, and a beam diffracted in the first and second directions to enter the objective lens. The width of the diffraction surface of the first diffraction element is rendered smaller than that of the region including the first and second light spots formed on the first diffraction element, whereby the part corresponding to the beam diffracted only in the first direction to enter the objective lens and that corresponding to the beam diffracted only in the second direction to enter the objective lens can be reduced in a region incident on the diffraction surface. Thus, it is possible to inhibit the light quantities of the beams diffracted in the first and second directions from non-uniformity resulting from optical axis deviation of the optical axis of the beam emitted from the light source, thereby suppressing non-uniform output of a tracking error detection signal utilizing the beams diffracted in the first and second directions respectively following optical axis deviation.
In particular, the width of the diffraction surface of the first diffraction element in the aforementioned plane is preferably set to be smaller than that of an overlap region of the first and second light spots on the first diffraction element.
In this case, the light quantities of the diffracted beams diffracted in the first and second directions respectively to enter the objective lens are equally changed even if the optical axis of the beam emitted from the light source deviates from a prescribed direction. Thus, the tracking error signal based on the diffracted beams in the first and second directions is reliably prevented from offset.
In particular, the first and second directions for diffracting the beams by the diffraction surface of the first diffraction element are preferably +1st and xe2x88x921st order directions respectively.
Assuming that R represents the aperture radius of the objective lens, L1 and L2 represent effective distances between the light source and the center of the objective lens and between the diffraction surface and the light source respectively and S represents the distance between a first virtual light source supposed to emit a straight beam equivalent to the beam diffracted in the first direction toward the objective lens and the light source or between a second virtual light source supposed to emit a straight beam equivalent to the beam diffracted in the second direction toward the objective lens and the light source, the width W of the diffraction surface of the first diffraction element is preferably set to satisfy the following relation:
Wxe2x89xa62xc3x97{(R+S)xc3x97L2/L1xe2x88x92S}
When the width W of the diffraction surface of the first diffraction element is set to satisfy the above relation, the beams of the beam emitted from the light source diffracted in the first and second directions, based on a common beam part, enter the objective lens. Even if the optical axis of the beam emitted from the light source deviates, therefore, the light quantities of the diffracted beams diffracted in the first and second directions are equally changed. Thus, it is possible to prevent offset of the tracking error signal based on the beams diffracted in the first and second directions.
Assuming that X1 represents the physical distance between the light source and the center of the objective lens and d and n represent the thickness and the refractive index of the first diffraction element respectively, the effective distance L1 is defined as follows:
L1=X1xe2x88x92(nxe2x88x921)xc3x97d/n
Assuming that X2 represents the physical distance between the light source and the diffraction surface and d and n represent the thickness and the refractive index of the first diffraction element respectively, the effective distance L2 is defined as follows:
L2=X2xe2x88x92(nxe2x88x921)xc3x97d/n
An optical pickup apparatus according to still another aspect of the present invention comprises a light source emitting a beam, a first diffraction element for diffracting the beam emitted from the light source at least in first and second directions, and an objective lens for irradiating an optical recording medium with beams diffracted by the first diffraction element in the first and second directions respectively. The objective lens is provided to be movable along the radial direction of the optical recording medium for a tracking operation, and the diffraction surface of the first diffraction element is so formed that the width in a plane including the optical axis of the beam emitted from the light source and axes of the beams diffracted in the first and second directions respectively is smaller than that of a region including a first light spot and a second light spot and dimensions are set for locating a light spot formed on the objective lens by the beams diffracted by the diffraction surface in the first and second directions respectively in an aperture of the objective lens following movement of the objective lens for the tracking operation. The first light spot is a light spot on the first diffraction element corresponding to a part of the beam, diffracted by the first diffraction element in the first direction, entering the objective lens in the beam emitted from the light source and the second light spot is a light spot on the first diffraction element corresponding to a part of the beam, diffracted by the first diffraction element in the second direction, entering the objective lens in the beam emitted from the light source.
In this case, the width of the diffraction surface of the first diffraction element is rendered smaller than that of the region including the first and second light spots formed on the first diffraction element thereby reducing non-uniformity of the light quantities of the diffracted beams in the first and second directions resulting from optical axis deviation of the beam emitted from the light source, to be capable of suppressing non-uniform output of a tracking error detection signal utilizing the diffracted beams diffracted in the first and second directions resulting from optical axis deviation.
Even if the objective lens is moved for the tracking operation, all diffracted beams pass through the objective lens to be condensed on the optical recording medium. Therefore, the light quantities of the diffracted beams condensed on the optical recording medium remain unchanged regardless of movement of the objective lens. Thus, it is possible to prevent output fluctuation of the tracking error signal resulting from change of the light quantities of the diffracted beams on the optical recording medium following the tracking operation.
In particular, the width of the diffraction surface of the first diffraction element in the aforementioned plane is preferably set to be smaller than that of an overlap region of the first and second light spots formed on the first diffraction element.
In this case, the light quantities of the beams diffracted in the first and second directions to enter the objective lens are equally changed even if the optical axis of the beam emitted from the light source deviates from a prescribed direction. Thus, it is possible to reliably prevent offset of the tracking error signal based on the diffracted beams in the first and second directions.
The optical pickup apparatus may further comprise a second diffraction element for guiding the beams diffracted by the first diffraction element in the first and second directions respectively and guiding the same to the objective lens while diffracting returned beams from the optical recording medium and a photodetector for receiving the returned beams diffracted by the second diffraction element.
In this case, the second diffraction element diffracts the returned beams from the optical recording medium for guiding the same to the photodetector, so that the tracking error signal by the photodetector can be detected.
An optical pickup apparatus according to a further aspect of the present invention, which can detect a tracking state of a beam for reading information from an optical recording medium, comprises a light source for emitting the beam, a first diffraction element for dividing the beam emitted from the light source into a plurality of beams for tracking state detection, an objective lens provided to be movable in the radial direction of the optical recording medium for condensing the plurality of beams divided by the first diffraction element on the optical recording medium, a photodetector having a plurality of photodetection parts for receiving a plurality of returned beams based on the plurality of beams for tracking state detection respectively and outputting a plurality of detection signals responsive to the received light quantities, an adjusting circuit capable of changing the plurality of detection signals outputted from the plurality of photoreceiving parts of the photodetector, and a lens driving part for radially moving the objective lens in response to a prescribed signal based on the plurality of detection signals adjusted by the adjusting circuit.
The optical pickup apparatus according to this aspect of the present invention can change the plurality of detection signals for tracking state detection by the adjusting circuit for moving the objective lens by the prescribed signal based on the changed detection signals. Thus, it is possible to correct deviation of the objective lens by adjusting the adjusting circuit for changing the detection signals in correspondence to the amount of deviation of the central portion of the objective lens from the optical axis of the beam.
Further, the optical pickup apparatus itself is provided with the adjusting circuit, whereby the adjusting circuit can be adjusted in an assembling stage of the optical pickup apparatus. Thus, adjustment for correcting deviation of the objective lens can be omitted in an apparatus assembled with the optical pickup apparatus.
In particular, the adjusting circuit preferably includes a variable resistor for changing the plurality of detection signals outputted from the plurality of photoreceiving parts of the photodetector.
In this case, the resistance value of the variable resistor can be so adjusted as to readily change the prescribed signal supplied to the lens driving part, for correcting deviation of the objective lens.
In particular, the optical pickup apparatus may further comprise a wiring part for extracting the signals from the plurality of photoreceiving parts of the photodetector, so that the variable resistor is arranged on the wiring part.
In this case, it is possible to readily change the prescribed signal supplied to the lens driving part by adjusting the resistance value of the variable resistor arranged on the wiring part, for correcting deviation of the objective lens.
In particular, the wiring part is preferably formed on a flexible circuit board. In this case, the degree of freedom in mounting of the wiring part in the optical pickup apparatus is improved due to the flexibility of the flexible circuit board, so that the optical pickup apparatus can be minimized.
In particular, the optical pickup apparatus preferably further comprises a plurality of amplifier parts provided in correspondence to the plurality of photoreceiving parts in the photodetector for amplifying differences between the detection signals outputted from the corresponding photoreceiving parts and a reference signal respectively, and the adjusting circuit preferably includes a variable resistor for changing the reference signal supplied to at least one of the plurality of amplifier parts.
In this case, it is possible to readily change the prescribed signal supplied to the lens driving part by adjusting the variable resistor and changing the reference signal, for correcting deviation of the objective lens.
In particular, the photoreceiving parts and the plurality of amplifier parts are formed on a single chip. In this case, the optical pickup apparatus is suitable for miniaturization.
The optical recording medium drive according to the present invention, which is adapted to optically read information from an optical recording medium, comprises a rotation driving part for rotating the optical recording medium, an optical pickup apparatus for irradiating the optical recording medium with a laser beam and receiving a returned beam from the optical recording medium, a pickup driving part for moving the optical pickup apparatus in the radial direction of the optical recording medium, and a signal processing part for processing an output signal from the optical pickup apparatus. Further, the optical pickup apparatus comprises a light source for emitting the beam, a diffraction element having a diffraction surface for diffracting the beam emitted from the light source at least in first and second directions, and an objective lens for irradiating the optical recording medium with beams diffracted by the diffraction element in the first and second directions respectively. The objective lens is provided to be movable along the radial direction of the optical recording medium for a tracking operation, and the diffraction surface of the diffraction element is formed in dimensions for locating a light spot formed on the objective lens by the beams diffracted by the diffraction surface in the first and second directions respectively in an aperture of the objective lens following movement of the objective lens for the tracking operation.
Thus, the light quantities of the diffracted beams on the optical recording medium remain unchanged in the tracking operation, and an optical recording medium drive causing no output reduction of a tracking error signal can be obtained.
An optical recording medium drive unit according to a further aspect of the present invention, which is adapted to optically read information from an optical recording medium, comprises a rotation driving part for rotating the optical recording medium, an optical pickup apparatus for irradiating the optical recording medium with a laser beam and receiving a returned beam from the optical recording medium, a pickup driving part for moving the optical pickup apparatus in the radial direction of the optical recording medium, and a signal processing part for processing an output signal from the optical pickup apparatus. Further, the optical pickup apparatus comprises a light source for emitting the beam, a diffraction element having a diffraction surface for diffracting the beam emitted from the light source at least in first and second directions, and an objective lens for irradiating the optical recording medium with beams diffracted by the diffraction element in the first and second directions respectively. The width of the diffraction surface of the diffraction element in a plane including the optical axis of the beam emitted from the light source and axes of the beams diffracted in the first and second directions is set to be smaller than the width of a region including a first light spot and a second light spot. The first light spot is a light spot on the diffraction element corresponding to a part of the beam, diffracted by the diffraction element in the first direction, entering the objective lens in the beam emitted from the light source and the second light spot is a light spot on the diffraction element corresponding to a part of the beam, diffracted by the diffraction element in the second direction, entering the objective lens in the beam emitted from the light source.
In this case, offset of a tracking error signal is prevented even if the optical axis of the beam from the light source in the optical pickup apparatus deviates, whereby no offset adjustment is required and correct tracking control can be performed.
An optical recording medium drive according to a further aspect of the present invention, which is adapted to optically read information from an optical recording medium, comprises a rotation driving part for rotating the optical recording medium, an optical pickup apparatus for irradiating the optical recording medium with a laser beam and receiving a returned beam from the optical recording medium, a pickup driving part for moving the optical pickup apparatus in the radial direction of the optical recording medium, and a signal processing part for processing an output signal from the optical pickup apparatus. Further, the optical pickup apparatus comprises a light source for outputting the beam, a diffraction element for dividing the beam emitted from the light source into a plurality of beams for tracking state detection, an objective lens provided to be movable in the radial direction of the optical recording medium for condensing the plurality of beams divided by the diffraction element on the optical recording medium, a photodetector having a plurality of photoreceiving parts for receiving a plurality of returned beams based on the plurality of beams for tracking state detection condensed on the optical recording medium respectively for outputting detection signals responsive to the received light quantities, an adjusting circuit capable of changing the plurality of detection signals outputted from the plurality of photoreceiving parts of the photodetector, and a lens driving part for radially moving the objective lens in response to a prescribed signal based on the plurality of detection signals adjusted by the adjusting circuit.
The optical pickup apparatus adjusted to output a tracking signal for correcting deviation of the objective lens is assembled into the optical recording medium drive according to the present invention, whereby no adjustment of deviation of the objective lens of the optical pickup apparatus is required after assembling and the optical recording medium drive is easy to assemble.
The method of adjusting an optical pickup apparatus according to the present invention, which is adapted to correct deviation of a central portion of an objective lens with respect to the optical axes of a plurality of beams in the radial direction of an optical recording medium in the optical pickup apparatus comprising a light source for emitting a beam, a diffraction element for dividing the beam emitted from the light source into the plurality of beams for tracking state detection, the objective lens for condensing the plurality of beams divided by the diffraction element on the optical recording medium, a lens driving part for moving the objective lens in the radial direction of the optical recording medium, and a photodetector having a plurality of photoreceiving parts for receiving a plurality of returned beams based on the plurality of beams for tracking state detection condensed on the optical recording medium respectively and outputting a plurality of detection signals responsive to the received light quantities, provides the optical pickup apparatus with an adjusting circuit capable of changing the detection signals outputted from the plurality of photoreceiving parts, connects a driving circuit for generating a driving signal for moving the objective lens in the radial direction on the basis of the detection signals outputted from the photodetector through the adjusting circuit to the lens driving part of the optical pickup apparatus, moves the objective lens in the radial direction by changing the detection signals with the adjusting circuit and thereafter observes change of the detection signals while radially moving the objective lens by a prescribed distance, thereby correcting deviation of the central portion of the objective lens with respect to the optical axes of the plurality of beams in the radial direction of the optical recording medium.
The method of adjusting an optical pickup apparatus according to the present invention connects the previously prepared driving circuit to the lens driving part of the optical pickup apparatus, changes the plurality of detection signals for tracking state detection with the adjusting circuit, and moves the objective lens by the prescribed signal based on the changed detection signals. The method further reciprocates the objective lens in the radial direction by prescribed distances for inspecting the state of deviation of the objective lens, obtains the current detection signals, and observes change of the detection signals. The adjusting circuit adjusts the detection signals to attain desired values. Thus, it is possible to correct deviation of the central portion of the objective lens by adjusting the adjusting circuit to change the detection signals in response to the amount of deviation of the mounting position of the objective lens with respect to the optical axes of the beams.
Further, the optical pickup apparatus itself is provided with the adjusting circuit, whereby the adjusting circuit can be adjusted in an assembling stage of the optical pickup apparatus. Thus, adjustment for correcting deviation of the central portion of the objective lens of the optical pickup apparatus can be omitted in the apparatus assembled with the optical pickup apparatus.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

Optical pickup apparatus employing an adjusting circuit


An odd order MESFET frequency multiplier which outputs a desired odd harmonic of a fundamental tone. The frequency multiplier includes a multiplier stage with a MESFET having a harmonic response dependent upon a plurality of bias conditions and the input RF power level. The MESFET includes a drain port coupled to an output matching network sized and configured for a predetermined load at a selected output frequency. The output matching network includes RF shorts for reflecting energy to the MESFET from a plurality of undesired even harmonics. Coupled to the output matching circuit is a bandpass filter sized and configured for the predetermined load. The bandpass filter includes RF shorts for reflecting energy to the MESFET from a plurality of undesired odd harmonics, wherein the reflected energy from the undesired even harmonics and the undesired odd harmonics are combined at the MESFET to provide additional energy at the desired odd harmonic.

An ever increasing demand for stable compact local oscillator sources in military and commercial communication systems established a need for frequency multipliers. The frequency multiplier with a single nonlinear MESFET (metal-semiconductor field effect transistor) is an efficient, low power way of satisfying the demand. Typically, a conventional oscillator generates a submultiple signal which is input to the frequency multiplier, thereafter, the frequency multiplier outputs a desired multiple frequency or output frequency.
Currently, there are active frequency multipliers and passive frequency multipliers with input frequencies above 2 GHz. The passive frequency multipliers often use diode multiplication technology which has several disadvantages when compared to active frequency multipliers. Some of the disadvantages associated with diode multipliers includes temperature induced parasitic oscillation, high input power requirement and narrow bandwidth. Also, extensive filtering is required to suppress unwanted harmonics.
Active frequency multipliers have several advantages including low power operation, wide bandwidth, low distortion, small dimensions, and temperature stability. However, traditional "odd order" active multipliers require the use of an idler circuit to short the fundamental frequency. The idler circuit appears as a small inductance connected to the MESFET and ground. A problem with the idler circuit is that it limits the bandwidth of the frequency multiplier, thereby adversely affecting the performance of the frequency multiplier.
Accordingly there is a need for a "odd order" MESFET frequency multiplier that displays improved efficiency across a broadband with low AM-to-FM conversion noise and enhanced spurious suppression. There is also a requirement to minimize the use of an idler circuit without sacrificing performance. These and other needs are satisfied by the odd order MESFET frequency multiplier of the present invention.


The present invention concerns affinity matured CRIg variants. In particular, the invention concerns CRIg variants having increased binding affinity to C3b and retaining selective binding to C3b over C3.

The Complement System
The complement system is a complex enzyme cascade made up of a series of serum glycoproteins that normally exist in inactive, pro-enzyme form. Three main pathways, the classical, alternative and mannose-binding lectin pathway, can activate complement, which merge at the level of where two similar C3 convertases cleave C3 into C3a and C3b.
Macrophages are specialist cells that have developed an innate capacity to recognize subtle differences in the structure of cell-surface expressed identification tags, so called molecular patterns (Taylor, et al., Eur J Immunol 33, 2090-1097 (2003); Taylor, et al., Annu Rev Immunol 23, 901-944 (2005)). While the direct recognition of these surface structures is a fundamental aspect of innate immunity, opsonization allows generic macrophage receptors to mediate engulfment, increasing the efficiency and diversifying recognition repertoire of the phagocyte (Stuart and Ezekowitz, Immunity 22, 539-550 (2005)). The process of phagocytosis involves multiple ligand-receptor interactions, and it is now clear that various opsonins, including immunoglobulins, collectins, and complement components, guide the cellular activities required for pathogen internalization through interaction with macrophage cell surface receptors (reviewed by Aderem and Underhill, Annu Rev Immunol 17, 593-623 (1999); Underhill and Ozinsky, Annu Rev Immunol 20, 825-852 (2002)). While natural immunoglobulins encoded by germline genes can recognize a wide variety of pathogens, the majority of opsonizing IgG is generated through adaptive immunity, and therefore efficient clearance through Fc receptors is not immediate (Carroll, Nat Immunol 5, 981-986 (2004)). Complement, on the other hand, rapidly recognizes pathogen surface molecules and primes the particle for uptake by complement receptors (Brown, Infect Agents Dis 1, 63-70 (1991)).
Complement consists of over 30 serum proteins that opsonize a wide variety of pathogens for recognition by complement receptors. Depending on the initial trigger of the cascade, three pathways can be distinguished (reviewed by (Walport, N Engl J Med 344, 1058-1066 (2001)). All three share the common step of activating the central component C3, but they differ according to the nature of recognition and the initial biochemical steps leading to C3 activation. The classical pathway is activated by antibodies bound to the pathogen surface, which in turn bind the C1q complement component, setting off a serine protease cascade that ultimately cleaves C3 to its active form, C3b. The lectin pathway is activated after recognition of carbohydrate motifs by lectin proteins. To date, three members of this pathway have been identified: the mannose-binding lectins (MBL), the SIGN-R1 family of lectins and the ficolins (Pyz et al., Ann Med 38, 242-251 (2006)) Both MBL and ficolins are associated with serine proteases, which act like C1 in the classical pathway, activating components C2 and C4 leading to the central C3 step. The alternative pathway contrasts with both the classical and lectin pathways in that it is activated due to direct reaction of the internal C3 ester with recognition motifs on the pathogen surface. Initial C3 binding to an activating surface leads to rapid amplification of C3b deposition through the action of the alternative pathway proteases Factor B and Factor D. Importantly, C3b deposited by either the classical or the lectin pathway also can lead to amplification of C3b deposition through the actions of Factors B and D. In all three pathways of complement activation, the pivotal step in opsonization is conversion of the component C3 to C3b. Cleavage of C3 by enzymes of the complement cascades exposes the thioester to nucleophilic attack, allowing covalent attachment of C3b onto antigen surfaces via the thioester domain. This is the initial step in complement opsonization. Subsequent proteolysis of the bound C3b produces iC3b, C3c and C3dg, fragments that are recognized by different receptors (Ross and Medof, Adv Immunol 37, 217-267 (1985)). This cleavage abolishes the ability of C3b to further amplify C3b deposition and activate the late components of the complement cascade, including the membrane attack complex, capable of direct membrane damage. However, macrophage phagocytic receptors recognize C3b and its fragments preferentially; due to the versatility of the ester-bond formation, C3-mediated opsonization is central to pathogen recognition (Holers et al., Immunol Today 13, 231-236 (1992)), and receptors for the various C3 degradation products therefore play an important role in the host immune response.
C3 itself is a complex and flexible protein consisting of 13 distinct domains. The core of the molecule is made up of 8 so-called macroglobulin (MG) domains, which constitute the tightly packed α and β chains of C3. Inserted into this structure are CUB (C1r/C1s, Uegf and Bone mophogenetic protein-1) and TED domains, the latter containing the thioester bond that allows covalent association of C3b with pathogen surfaces. The remaining domains contain C3a or act as linkers and spacers of the core domains. Comparison of C3b and C3c structures to C3 demonstrate that the molecule undergoes major conformational rearrangements with each proteolysis, which exposes not only the TED, but additional new surfaces of the molecule that can interact with cellular receptors (Janssen and Gros, Mol Immunol 44, 3-10 (2007)).
Complement C3 Receptors on Phagocytic Cells
There are three known gene superfamilies of complement receptors: The short consensus repeat (SCR) modules that code for CR1 and CR2, the beta-2 integrin family members CR3 and CR4, and the immunoglobulin Ig-superfamily member CRIg.
CR1 is a 180-210 kDa glycoprotein consisting of 30 Short Consensus Repeats (SCRs) and plays a major role in immune complex clearance. SCRs are modular structures of about 60 amino acids, each with two pairs of disulfide bonds providing structural rigidity. High affinity binding to both C3b and C4b occurs through two distinct sites, each composed of 3 SCRs) reviewed by (Krych-Goldberg and Atkinson, Immunol Rev 180, 112-122 (2001)). The structure of the C3b binding site, contained within SCR 15-17 of CR1 (site 2), has been determined by MRI (Smith et al., Cell 108, 769-780 (2002)), revealing that the three modules are in an extended head-to-tail arrangement with flexibility at the 16-17 junction. Structure-guided mutagenesis identified a positively charged surface region on module 15 that is critical for C4b binding. This patch, together with basic side chains of module 16 exposed on the same face of CR1, is required for C3b binding. The main function of CR1, first described as an immune adherence receptor (Rothman et al., J Immunol 115, 1312-1315 (1975)), is to capture ICs on erythrocytes for transport and clearance by the liver (Taylor et al., Clin Immunol Immunopathol 82, 49-59 (1997)). There is a role in phagocytosis for CR1 on neutrophils, but not in tissue macrophages (Sengelov et al., J Immunol 153, 804-810 (1994)). In addition to its role in clearance of immune complexes, CR1 is a potent inhibitor of both classical and alternative pathway activation through its interaction with the respective convertases (Krych-Goldberg and Atkinson, 2001, supra; Krych-Goldberg et al., J Biol Chem 274, 31160-31168 (1999)). In the mouse, CR1 and CR2 are two products of the same gene formed by alternative splicing and are primarily associated with B-lymphocytes and follicular dendritic cells and function mainly in regulating B-cell responses (Molina et al., 1996). The mouse functional equivalent of CR1, Crry, inactivates the classical and alternative pathway enzymes and acts as an intrinsic regulator of complement activation rather than as a phagocytic receptor (Molina et al., Proc Natl Acad Sci USA 93, 3357-3361 (1992)).
CR2 (CD21) binds iC3b and C3dg and is the principal complement receptor that enhances B cell immunity (Carroll, Nat Immunol 5, 981-986 (2004); Weis et al., Proc Natl Acad Sci USA 81, 881-885 (1984)). Uptake of C3d-coated antigen by cognate B cells results in an enhanced signal via the B cell antigen receptor. Thus, coengagement of the CD21-CD19-CD81 coreceptor with B cell antigen receptor lowers the threshold of B cell activation and provides an important survival signal (Matsumoto et al., J Exp Med 173, 55-64 (1991)). The CR2 binding site on iC3b has been mapped partly on the interface between the TED and the MG1 domains (Clemenza and Isenman, J Immunol 165, 3839-3848 (2000)).
CR3 and CR4 are transmembrane heterodimers composed of an alpha subunit (CD11b or αM and CD11c or αx, respectively) and a common beta chain (CD18 or β2), and are involved in adhesion to extracellular matrix and to other cells as well as in recognition of iC3b. They belong to the integrin family and perform functions not only in phagocytosis, but also in leukocyte trafficking and migration, synapse formation and costimulation (reviewed by (Ross, Adv Immunol 37, 217-267 (2000)). Integrin adhesiveness is regulated through a process called inside-out signaling, transforming the integrins from a low- to a high-affinity binding state (Liddington and Ginsberg, J Cell Biol 158, 833-839 (2002)). In addition, ligand binding transduces signals from the extracellular domain to the cytoplasm. The binding sites of iC3b have been mapped to several domains on the alpha chain of CR3 and CR4 (Diamond et al., J Cell Biol 120, 1031-1043 (1993); Li and Zhang, J Biol Chem 278, 34395-34402 (2003); Xiong and Zhang, J Biol Chem 278, 34395-34402 (2001)). The multiple ligands for CR3: iC3b, beta-glucan and ICAM-1, seem to bind to partially overlapping sites contained within the I domain of CD11b (Balsam et al., 1998; Diamond et al., 1990; Zhang and Plow, 1996). Its specific recognition of the proteolytically inactivated form of C3b, iC3b, is predicted based on structural studies that locate the CR3 binding sites to residues that become exposed upon unfolding of the CUB domain in C3b (Nishida et al., Proc Natl Acad Sci USA 103, 19737-19742 (2006)), which occurs upon α′ chain cleavage by the complement regulatory protease, Factor I.
CRIg is a macrophage associated receptor with homology to A33 antigen and JAM1 that is required for the clearance of pathogens from the blood stream. A human CRIg protein was first cloned from a human fetal cDNA library using degenerate primers recognizing conserved Ig domains of human JAM1. Sequencing of several clones revealed an open reading frame of 400 amino acids. Blast searches confirmed similarity to Z39Ig, a type 1 transmembrane protein (Langnaese et al., Biochim Biophys Acta 1492 (2000) 522-525). The extracellular region of this molecule was found to consist of two Ig-like domains, comprising an N-terminal V-set domain and a C-terminal C2-set domain. The novel human protein was originally designated as a "single transmembrane Ig superfamily member macrophage associated" (huSTIgMA). (huSTIgMA). Subsequently, using 3′ and 5′ primers, a splice variant of huSTIgMA was cloned, which lacks the membrane proximal IgC domain and is 50 amino acids shorter. Accordingly, the shorter splice variant of this human protein was designated huSTIgMAshort. The amino acid sequence of huSTIgMA (referred to as PRO362) and the encoding polynucleotide sequence are disclosed in U.S. Pat. No. 6,410,708, issued Jun. 25, 2002. In addition, both huSTIgMA and huSTIgMAshort, along with the murine STIgMA (muSTIgMA) protein and nucleic acid sequences, are disclosed in PCT Publication WO 2004031105, published Apr. 15, 2004.
The crystal structure of CRIg and a C3b:CRIg complex is disclosed in U.S. Application Publication No. 2008/0045697, published Feb. 21, 2008.
The Kupffer cells (KCs), residing within the lumen of the liver sinusoids, form the largest population of macrophages in the body. Although KCs have markers in common with other tissue resident macrophages, they perform specialized functions geared towards efficient clearance of gut-derived bacteria, microbial debris, bacterial endotoxins, immune complexes and dead cells present in portal vein blood draining from the microvascular system of the digestive tract (Bilzer et al., Liver Int 26, 1175-1186 (2006)). Efficient binding of pathogens to the KC surface is a crucial step in the first-line immune defense against pathogens (Benacerraf et al., J Exp Med 110, 27-48 (1959)). A central role for KCs in the rapid clearance of pathogens from the circulation is illustrated by the significantly increased mortality in mice depleted of KCs (Hirakata et al., Infect Immun 59, 289-294 (1991)). The identification of CRIg further stresses the critical role of complement and KCs in the first line immune defense against circulating pathogens.
The only complement C3 receptors identified on mouse KCs are CRIg and CR3 (Helmy et al., Cell 124, 915-927 (2006)), while human KCs show additional expression of CR1 and CR4 (Hinglais et al., 1989). Both CRIg and CR3 on KCs contribute to binding to iC3b opsonized particles in vitro (Helmy et al., Lab Invest 61, 509-514 (2006)). In vivo, a role of KC-expressed CR3 in the binding to iC3b-coated pathogens is less clear. CR3 has been proposed to contribute to clearance of pathogens indirectly via recruitment of neutrophils and interaction with neutrophil-expressed ICAMI (Conlan and North, Exp Med 179, 259-268 (1994); Ebe et al., Pathol Int 49, 519-532 (1999); Gregory et al., J Immunol 157, 2514-2520 (1996); Gregory and Wing, J Leukoc Biol 72, 239-248 (2002); Rogers and Unanue, Infect Immun 61, 5090-5096 (1993)). In contrast, CRIg performs a direct role by capturing pathogens that transit through the liver sinusoidal lumen (Helmy et al., 2006, supra). A difference in the biology of CRIg vs CR3 is in part reflected by difference in binding characteristics of these two receptors. CRIg expressed on KCs constitutively binds to monomeric C3 fragments whereas CR3 only binds to iC3b-opsonized particles (Helmy et al., 2006, supra). The capacity of CRIg to efficiently capture monomeric C3b and iC3b as well as C3b/iC3b-coated particles reflects the increased avidity created by a multivalent interaction between CRIg molecules concentrated at the tip of membrane extensions of macrophages (Helmy et al., 2006, supra) and multimers of C3b and iC3b present on the pathogen surface. While CR3 only binds iC3b-coated particles, CRIg additionally bind to C3b, the first C3 cleavage product formed on serum-opsonized pathogens (Croize et al., Infect Immun 61, 5134-5139 (1993)). Since a large number of C3b molecules bound to the pathogen surface are protected from cleavage by factor H and I (Gordon et al., J Infect Dis 157, 697-704 (1988)), recognition of C3b ligands by CRIg ensures rapid binding and clearance. Thus, while both CRIg and CR3 are expressed on KCs, they show different ligand specificity, distinct binding properties and distinct kinetics of pathogen clearance.
Examples of pathogens that exploit cell surface receptors for cellular entry are viruses like human immunodeficiency virus (HIV), and intracellular bacteria like Mycobacterium tuberculosum, Mycobacterium leprae, Yersinia pseudotuberculosis, Salmonella typhimurium and Listeria Monocytogenes and parasites like the prostigmatoid Leishmania major (Cossart and Sansonetti, Science 304:242-248 (2004); Galan, Cell 103:363-366 (2000); Hornef et al., Nat. Immunol. 3:1033-1040 (2002); Stoiber et al., Mol. Immunol. 42:153-160 (2005)).
As discussed above, CRIg is a recently discovered complement C3 receptor expressed on a subpopulation of tissue resident macrophages. Next to functioning as a complement receptor for C3 proteins, the extracellular IgV domain of CRIg selectively inhibits the alternative pathway of complement by binding to C3b and inhibiting proteolytic activation of C3 and C5. However, CRIg binding affinity for the convertase subunit C3b is low (IC50>1 μM) requiring a relatively high concentration of protein to reach near complete complement inhibition. Accordingly, there is a need for CRIg polypeptides with improved therapeutic efficacy. The present invention provides such polypeptides.


A display device includes a display unit in which display elements provided with pixel circuits are arranged so as to have a sequence of three different colors in a row direction and the colors are shifted in a column direction by 1.5 columns. A scanning line is provided in every row of the display unit, a signal line is provided in every column of the display unit, and a column control circuit outputs a display signal for every column. The positions of the pixel circuits are displaced in the row direction with respect to the arrangement of the display elements, and are thus aligned in the column direction and also connected to the signal line only on one side of the signal line. No inversion of the pixel circuit pattern occurs and variations of the circuit characteristics in every row are suppressed.

1. Field of the Invention
The present invention relates to an active matrix display device.
2. Description of the Related Art
An electroluminescence element (hereinafter referred to as EL element) is a light-emitting element for emitting light when a current is injected thereto. In an active matrix EL display device, EL elements are arranged in a matrix to form pixels, and pixel circuits are provided for supplying currents to the EL elements of the respective pixels.
The pixel circuits are controlled by scanning lines and signal lines. Each scanning line is commonly provided to pixel circuits arranged in a respective row. Through the connection to those pixel circuits, a signal for selecting the pixel circuit in every row is applied. The signal lines are connected to pixel circuits arranged in a respective column, and a signal corresponding to image information is applied.
US Patent Laid-Open No. 2004/0066357 proposes a pixel circuit in which two signal lines including a signal line for supplying a current signal and a signal line for supplying a voltage signal are provided.
There are two types for arrangement of the pixels, which are a stripe arrangement and a delta arrangement. According to the stripe arrangement, pixels are linearly arranged. According to the delta arrangement, three pixels of RGB which constitute a color display unit are arranged in a delta shape. In a small size display device whose pixel number is small, the delta arrangement is used for the pixel array in many cases for improving definition.
FIG. 6 shows an example of the delta arrangement. In the delta arrangement, pixels of RGB in the row direction are periodically arranged as one sequence, and the pixels adjacent to the pixels in the row direction are shifted in the arrangement sequence by 1.5 pixels.
In a color display device that employs the delta arrangement, an R pixel R1 and a G pixel G1 adjacent to each other in one row forms a pair with a B pixel B1 arranged immediately beneath the row to compose a color display unit. Then, a B pixel B2 adjacent thereto forms a pair with an R pixel R2 and a G pixel G2 immediately beneath the row to compose another color display unit.
In FIG. 6, scanning lines X1, X2, . . . and signal lines Y1, Y2, . . . are also drawn.
In a transmissive liquid crystal device, scanning lines and signal lines are arranged between a pixel and another pixel in order to increase a pixel aperture ratio. In a matrix display device that employs the delta arrangement, it is possible to arrange scanning lines straight through, but it is necessary to thread signal lines among the pixels in a bending manner. Moreover, in order that pixels of the same color are connected to each other by one signal line, connection points C1 and C2 with respect to the pixel circuit are located on the opposite sides in every row.
The connection positions with respect to the signal line are inverted in every row and thus the pixel circuit patterns are arranged so as to be inverted. For this reason, in a precise sense, variations every other row occur in characteristics of TFT elements that compose the pixel circuits. In order to have uniform display characteristics, it is desired to employ a uniform pixel circuit pattern without such inversion.
In a reflective liquid crystal display device or a top emission EL display device, pixel circuits do not block transmitted light, and it is therefore unnecessary to arrange signal lines between pixels and it is also possible to extend the signal lines straight through across the pixel region. However, in the EL display device, the pixel circuit needs to include a few transistors and a power source wiring whose width is large so that a large current flows. For this reason, if the pixel density becomes high, the pixel circuits occupy the entirety of the pixel area. In that case, it is difficult to arrange the signal lines straight through across near the center of the pixel region, and eventually the wiring is bent along a side of the pixel circuit pattern.
U.S. Pat. No. 6,768,482 proposes a top emission EL display device having pixels that are arranged in delta. In this device, a pitch of pixel array in a row direction is set two times larger than a pixel circuit pitch, and instead a pitch of pixel array in a column direction is set half of the pixel circuit pitch, whereby even when the pixels arranged in delta, it is possible to arrange pixel circuits straight through in a stripe manner. Also, it is possible to arrange the signal lines straight through without bending.
However, if the pixel array pitch is further decreased, the pixel circuits need to be arranged at a density two times larger than the degree of decreasing the pixel array pitch. Thus, it is necessary to extremely decrease the sizes of transistors and wirings that compose the pixel circuits. The sizes of the circuit elements and the wiring have lower limits so as to ensure fabrication yield, and setting the pixel circuit pitch smaller than the pixel pitch causes unnecessary disadvantages at the time of pursuing the high definition.


A communication system such as a distributed packet switch, is described, including multiple nodes with bi-directional transmission links between the nodes, each link comprising of a set of multiple links in parallel. The system provides an automatic balancing the aggregate capacity of one set of links in a proportion “M:N” to the aggregate capacity of the other set of links under varying link conditions, including one or more individual link failures in one or both sets of links.

A system architecture that is suitable for high capacity switches includes a set of nodes, each node containing external input/output (I/O) ports as well as being part of a distributed switching fabric.
In U.S. Pat. No. 6,370,145 (Dally, et al.) is described an example of a switching system (an internet router) which is composed of a multi-hop network of fabric routers (nodes or switch elements) which effectively constitute a distributed switch fabric providing connectivity between I/O ports contained within the fabric routers.
User data traffic may enter the system at an I/O port of one of the nodes (the ingress node) and leave through an I/O port of another node (the egress node). Traffic may be routed from one I/O port of a node to an I/O port on the same node, but the case of greater interest is where the egress node differs from the ingress node. If the ingress node does not have a direct link to the egress node, data traffic is switched through a number of intermediate nodes acting as tandem nodes.
In a distributed fabric architecture, all nodes are of equal or similar design and contain means to fulfill the roles of ingress, tandem, and egress nodes dynamically as required.
To switch traffic, virtual circuits (VCs) are set up between ingress nodes and egress nodes, where the forward channel is used to transmit user data, and the reverse channel carries flow control (back pressure) signals. The reverse channel may also be carrying user data in the opposite direction, and flow control signals are usually combined with user traffic.
Such system architecture relies on large input buffers and output buffers associated with the I/O ports of each node, and an end-to-end flow control regime to guarantee a high quality of service. On its way from an ingress node to an egress node, traffic going through a tandem node however bypasses the I/O port buffers in the nodes that are acting as tandem nodes. As in any multi-stage fabric, the internal links between the nodes can be overloaded if appropriate measures are not taken.
A commonly used measure to prevent data loss is to provide link-by-link flow control on the internal links between the nodes. This is a second type of backpressure or flow control, in addition to the end-to-end flow control regime provided between ingress and egress nodes. For cost and delay reasons, the sizes of buffers in the tandem nodes are kept small, requiring a very fast flow control mechanism capable of providing rapid backpressure to the port buffers.
In U.S. Pat. No. 6,285,679 (Dally, et al.) is described a multi-hop distributed switch system in which virtual circuits (VCs) are set up between ingress and egress nodes, through tandem nodes containing small buffers, one per VC, that can fill up quickly. A credit based flow control scheme is employed to propagate the state of tandem buffers back to ingress nodes.
Complications may arise in the design of the nodes and the backpressure mechanism when the links between the nodes are not direct but are made up of multiple links in parallel. This arrangement may be chosen to provide a higher capacity of transmission between nodes than becomes possible, or economically viable, with a direct (back plane or fiber link) connection. However, the available higher capacity must be utilized effectively to carry the traffic stream and the flow control signals.
Ribbon fiber cables and high-speed multi-fiber electro-optical transceiver modules have recently become available to enable such a system design. In U.S. Pat. No. 6,307,906 (Tanji, et al.) is described the basic concept of using a ribbon fiber cable for module interconnect, including a clock and data recovery scheme. Unfortunately, using a ribbon fiber cable as a parallel bus to interconnect the modules of a system has some disadvantages, e.g. when errors or failures of individual links within the cable are considered. For example, when used as a simple parallel bus, the loss of an individual link renders the entire bus unusable.
Another method to use a ribbon fiber cable is to consider each fiber as a serial channel (carrying complete cells or packets), and then use an inverse multiplexing scheme to distribute the traffic over the fibers in the cable, typically in a round-robin mode. This method would result only in some loss of capacity when a single link fails.
Inverse multiplexing was first proposed on a network scale, to bundle multiple lower speed links into a single higher speed logical link. Network scale inverse multiplexing is described in numerous U.S. Pat. No., among which U.S. Pat. No. 5,608,733 (Vallee, et al.), U.S. Pat. No. 5,875,192 (Cam, et al.).
The use of inverse multiplexing on a module-to-module scale is described in U.S. Pat. No. 6,188,699 (Lang, et al.). In such a scheme each physical link uses individual transmit and receive circuits for conveying data from the transmitter to the receiver, and common management circuits and packet buffer processors for coordinating the transfer over the group of physical links.
However, existing inverse multiplexing schemes are only adapted to the transfer of data between nodes that are capable of terminating packet (cell or ATM) protocols in the case of network scale inverse multiplexing, or contain network processors or the like in the case of module scale inverse multiplexing.
In a large switching system with a large number of internal virtual circuits (VCs) each requiring a queue per VC in each tandem node through which the VC passes, and with very high speed links connecting the nodes to each other, there are two important requirements: the cost of the intermediate buffers must be kept as low as possible, but their sizes must be adequate to handle the feedback volume.
Feedback volume is a term used to describe the amount of traffic (number of data packets) that will arrive at a receiver after the receiver has sent a backpressure signal to the transmitter. The feedback volume depends on the link speed, and on the delay of both the data path from the transmitter to the receiver, and the feedback path from the receiver to the transmitter.
A large number of VC's implies a large number of queues, and also a large number of flow control signals, which must be conveyed rapidly from the receivers to the transmitters. A large amount of flow control traffic requires a significant amount of bandwidth that is then not available for data traffic. If less bandwidth is made available for flow control, the end-to-end delay for flow control signals from receiver to transmitter is increased, which has the effect of increasing the required size of buffers at the receiver.
As a consequence, a very careful design decision must be made to provide sufficiently rapid flow control without using up an inordinate amount of bandwidth for control signals.
A reliable method of flow control is based on the concept of continuously reporting the receiver's queue and buffer status to the transmitters. The queue status may be the number of buffer spaces available to the queue of a VC, or it may be a single logical bit to express whether a certain fill threshold has been exceeded for a queue. The buffer status (irrespective of VC) may similarly be a number expressing the total amount of space available in the buffer, or a single logical bit triggered when a certain fill threshold has been exceeded. Both VC queues and buffer space may be divided according to a number of priority levels, and status information may be generated separately for each priority. The queue and buffer status information can be carried in the header of data packets (cells), including the headers of idle cells, or it can be transmitted in the payload of designated flow control cells. Flow control cells could be transmitted whenever there are no user data cells to be transmitted, but in the critical high-load situation flow control cells must be inserted at a minimum rate.
When multiple links, for example a ribbon multi-fiber cable, are employed to interconnect nodes, the bandwidth available on the multi-fiber link as a whole is the sum of the bandwidths of the individual links. However, under failure conditions, the aggregate bandwidth available on the multi-fiber link as a whole can be reduced, which may lead to a problem of increasing of the feedback volume, and cause buffer overruns and data loss.
Accordingly, there is a need in the industry for further development of means and methods of handling data and back pressure signals over such multiple links under variable conditions.

Communication system with balanced transmission bandwidth


An air purifier including: a filter which removes contaminants from air passing therethrough; a fan which generates a flow force to pass air through the filter; and a rotating body rotatably mounted in the air purifier and defining a flow path around the fan, a discharge direction of the flow path being varied by rotation of the rotating body.

1. Field of the Invention
The present invention relates to an air purifier, and more particularly, to a freestanding air purifier in which a discharge direction of purified air can be varied.
2. Description of the Related Art
Generally, a freestanding air purifier defines a flow path around an axial flow fan vertically mounted therein for intaking and discharging ambient air, and has a filter provided at an intake port for filtrating contaminants present in ambient air. This type of air purifier is referred to as a freestanding air purifier since its body has a vertically extended shape.
In such a freestanding air purifier, a discharge port is formed at the opposite side of the intake port such that intake air at the intake port is purified by the filter and discharged to the opposite side thereof, and is formed with an auto-blade allowing a variation of a specified angle so as to vary a discharge angle of the purified air.
In the freestanding air purifier, an air-stream flows from the rear side of the air purifier provided with the intake port to the front side thereof provided with the discharge port. Here, although, in the case where the discharge angle of air is varied by means of the auto-blade, the variation of the air-stream is slight. As a result, the variation of the air-stream is considerably restricted, so that the overall air-stream is not significantly changed.
Accordingly, when indoor air is purified by the conventional air purifier as described above, there is a problem in that as the purified air is distributed mainly from the font side of the air purifier, the purified air is non-uniformly distributed depending on where the air purifier is positioned in an installation area, thereby making the degree of air pollution non-uniform in the installation area.
Furthermore, there is a problem in that, since the discharge of the purified air is concentrated in one direction, it takes a long time to purify the entire installation area, thereby lowering purification efficiency.

Air purifier and air purification method


Circuits and methods for implementing a residue amplifier are provided. In some embodiments, circuits for implementing a residue amplifier are provided, the circuits comprising: a first capacitor configured to be charged to an input voltage level and that discharges from the input voltage level to a reference voltage level; a comparator having a first input coupled to the first capacitor, a second input coupled to a reference voltage source, and an output that indicates when the charge on the first capacitor is above the reference voltage level; and a second capacitor configured to be charged to an output voltage based on the output of the comparator.

Pipelined Analog-to-Digital Converters (ADCs) are widely used in high speed communication systems and other applications. A pipelined ADC converts an analog input signal into a digital output signal by generating bits of the digital output signal in multiple pipelined stages. Each stage in the pipelined ADC performs two functions: (1) producing digital output bits; and (2) computing and amplifying a residue signal to be passed on to the next stage.
In the case of the widely used 1.5 bit/stage pipelined ADC architecture, the computation and amplification of the residue signal, Vres[N+1], output by an Nth stage of the pipelined ADC architecture typically implements the operation described in equation (1):
                                          V            res                                          [                          N              +              1                        ]                          =                  2          ·                      (                                                            V                  res                                                                  [                  N                  ]                                            -                              b                ·                                                      V                    REF                                    2                                                      )                                              (        1        )            where VREF is the reference voltage, and b is the sub-ADC output coded as −1,0, or 1.
Typical mechanisms for an accurate implementation of the 2× gain articulated in equation (1) have not been efficient in terms of power usage.
Accordingly, circuits and methods for implementing a residue amplifier are provided.

The Trustees of Columbia University in the City of New York