A method and apparatus for femtosecond transient absorption comprising phase-sensitive detection, spectral scanning and simultaneous controlling of a translation stage to obtain TA spectra information having at least a sensitivity two orders of magnitude higher than that for single-shot methods, with direct, simultaneous compensation for chirp as the data is acquired. The present invention includes a amplified delay translation stage which generates a splittable frequency-doubled laser signal at a predetermined frequency f, a controllable means for synchronously modulating one of the laser signals at a repetition rate of f/2, applying the laser signals to a material to be sample, and acquiring data from the excited sample while simultaneously controlling the controllable means for synchronously modulating.

Transient absorption (TA) refers to spectral measurements of the absorption of light by a material which has first been "pumped" from its ground electronic state to an excited electronic state by a transient pulse of light (pump beam). A probe pulse of light (probe beam) then follows at some fixed delay time after the pump, and the absorption of the probe beam by the material, as a function of delay time and wavelength, yields a series of TA spectra. These spectra are useful to examine and deduce the structure of the electronic energy levels above the electronic ground state, as well as examining the mechanisms for relaxation of electrons from their excited states back down to the ground state. It is desirable to know these properties of materials, both for purposes of basic understanding, and because the operation of electronic and optical devices made from such materials often depends sensitively on these properties. For example, inorganic semiconductors such as GaAs have been widely studied using TA in order to improve the operation of devices such as diode lasers.
The most common form of prior art TA spectral measurements utilizes a chargecoupled device (CCD) camera and a spectrometer for the rapid acquisition of an entire TA spectrum at a chosen time delay. This measurement methodology is known as single-shot TA spectroscopy. However, the phenomenon known as "chirp" may greatly affect the measurement data collected. In particular, "chirp" refers to the different arrival time of different wavelengths of light within a broadband probe pulse. Chirp can arise from many sources, but the most common source is material dispersion (the term forthe phenomenon that the refractive index of materials changes as a function of wavelength of light). For example, a broadband probe pulse passing through a glass lens or window would be subjected to chirp, because the longer wavelength portions of the pulse travel faster in the material due to the lower index of refraction of glass. Prior art broadband probe pulses "continuum" beams) are generated by focusing picosecond or femtosecond pulses through a transparent material such as water, glass, or sapphire. Hence, the use of the prior art continuum generation process inherently involves creation of chirp. There is no known method for preventing chirp or for completely removing chirp from a broadband continuum (spectral width more than 200 nanometers). As a result of chirp, the delay time for a transient absorption spectrum may not be uniquely defined for every wavelength. In particular, if the delay time is less than the total chirp over the probe pulse spectral range, then the TA spectrum will be distorted by the chirp. For example, in experiments, the chirp is approximately one picosecond across the visible spectrum (450-750 nanometers). Hence, visible TA spectra are severely distorted for delay times less than 1 picosecond.
Prior art single-shot TA methodologies can be deficient for several reasons. First, as discussed above, the chirp phenomena may affect the measurements obtained. The chirp can be eliminated over a narrow spectral range by pulse compression (e.g., by using transform limited pulses). Further, transform limited pulses allow the examined spectra to remain undistorted on all time scales. However, the bandwidth for the shortest obtainable pulses (such as, for example, five femtosecond pulses) is only approximately 200 nanometers, a fraction of what is achievable with continuum generation. Therefore, broadband spectroscopy beyond the transform limit requires chirp correction. Scientists normally attempt to correct the single-shot TA chirp effect by applying numerical correction. Numerical correction requires that uncorrected spectra be taken at closely spaced time intervals and deconvolved based on the measured chirp. In using the single-shot TA methodology, a numerical correction is usually applied because the entire (chirped) spectrum is obtained. Another serious limitation to single-shot acquisition is that array detectors preclude the use of electronic noise suppression in either the frequency (lock-in detection) or the time (gated integration) domains. And, the primary obstacle in using a CCD camera is the low-frequency noise generated by the camera itself, which sets a detection limit for single-shot TA of approximately 0.2%.
The prior art measurement techniques described above are faulty for several other reasons. CCD cameras, at relatively high incident light intensities, are easily saturated by the continuum beam. Since the continuum has a strongly varying intensity with wavelength (see, e.g., FIG. 2), it is difficult to obtain TA spectra over a broad spectral range which do not either saturate the camera or result in poor signal-to-noise ratios. Further, currently available scientific-grade CCD cameras are expensive. Accordingly, as those of skill in the art will appreciate, a simple method and apparatus is desirable for measuring TA spectra which are undistorted by effects of chirp and intensity variations on the continuum probe over a broad spectral range (visible to near-infrared range) which has high sensitivity (on the order of approximately 10.sup.-5).
With the widespread availability of tunable, millijoule pulse energy, kHz repetition-rate femtosecond solid-state Ti:sapphire lasers, femtosecond transient absorption (TA) measuring techniques are now becoming the standard techniques for measuring ultra fast electronic and vibrational processes in material physics, chemistry, and biology. Unlike prior art TA measuring techniques, femtosecond chirp-free TA measuring techniques have the advantage of measuring subpicosecond energy relaxation, which is an important consideration in examining materials because it is during these short delay times that more spectral distortion occurs.
Further, phase-sensitive detection has long been a standard for measuring single wavelength pump-probe dynamics with high-repetition-rate (100-MHZ) lasers. This technique involves modulation of the intensity of the pump beam at a frequency which is lower than the repetition rate f (e.g. by using a mechanical chopper or acousto-optic or electro-optic modulator). A lock-in amplifier is then used to detect the modulation at the same frequency, which is transferred to the probe beam by the TA signal in the material. However, two modifications are necessary to optimize this technique for kilohertz repetition rate sources. First, differential amplification is necessary prior to the lock-in as it allows one to null the background signal due to the kilohertz laser pulse train, which prevents overload of the lock-in owing to insufficient dynamic reserve. The intensity variation over the continuum spectrum (as seen in FIG. 2) also makes the use of differential amplification important. In this fashion, the dynamic range is determined primarily by the photodiodes and is much greater than the range for CCD cameras. Second, synchronous modulation (chopper synchronized to exactly half the repetition rate) is necessary as it prevents phase drift between pump and chopper.
As is known to those of skill in the art, broadband femtosecond continuum pulses can be generated through self-phase modulation by focusing a laserthrough a transparent medium. It is possible to generate tunable probe beams at fixed wavelengths by other means (e.g. frequency-doubling, parametric generation, sum- and difference-frequency generation). However, no means are known other than continuum generation to obtain short pulses of light which simultaneously possess many different wavelengths. As such, a benefit of applying continuum pulses to TA methodologies is that they provide an opportunity to examine the energy structure of materials over a broader spectral width. In addition to the desired broad spectral width, continuum pulses have two unique characteristics uncommon to narrow band light sources. First, a continuum pulse exhibits a frequency temporal dispersion (or, chirp) as the pulse engages the material so that the red portion of the pulse arrives at an earlier time than the blue portion as described above. Second, a continuum exhibits a strong spectral nonuniformity with an intensity spike at the pump wavelength. Graphically, this is illustrated in FIGS. 1 and 2.
Accordingly, it is an object of the present invention to provide a highly sensitive, chirp-free femtosecond transient absorption spectroscopy scanning method which permits direct visualization and modeling of ultra fast, broadband energy relaxation.
It is another object of the present invention to provide a highly sensitive, chirp-free femtosecond transient absorption spectroscopy apparatus which permits direct visualization and modeling of ultra fast, broadband energy relaxation.
It is another object of the present invention to provide an apparatus which achieves highly sensitive chirp-free transient absorption spectroscopy measurements.
It is a further object of the present invention to provide a highly sensitive, chirp-free femtosecond transient absorption spectroscopy apparatus using a Tl:sapphire laser source, wherein two or more laser signals are applied to a material to be sampled for data acquisition.
It is a further object of the present invention to provide a method and apparatus for femtosecond transient absorption comprising phase-sensitive detection, spectral scanning and simultaneous controlling of a delay translation stage resulting in highly-sensitive, chirp-free measurements of femtosecond transient absorption characteristics of a material over the entire bandwidth of a white-light or infrared continuum.
Additional objects, advantages and novel features of the invention will be set forth in part in the description that follows, and in part will become apparent to those of skill in the art upon examination of the following description or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

Femtosecond chirp-free transient absorption method and apparatus


A radio base station for a wireless communication system is disclosed. The radio base station has wireless communication equipment, an enclosure, an air conditioning system, and a notification system. The wireless communication equipment receives, processes, and transmits frequencies in at least one range of 806-960 MHz, 1710-1855 MHz, 2500-2690 MHz, and 2.4 GHz-2.5 GHz. The enclosure has an interior region, and the enclosure houses the wireless communication equipment within the interior region. The air conditioning system cools the interior region. The notification system monitors the air conditioning system, and the notification system communicates with a communications network and sends a notification when the air conditioning system operates. The notification system thus provides an alert when the air conditioning system is cooling the wireless communication equipment.

A portion of the disclosure of this patent document and its figures contain material subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, but otherwise reserves all copyrights whatsoever.
1. Field of the Invention
This invention generally relates to wireless communications and, more particularly, to radio base stations that monitor cooling systems.
2. Description of the Related Art
Wireless communication has experienced explosive growth. In just a few years cellular telephone usage has soared, and growth continues as wireless Internet access improves. This explosive growth has revolutionized data and voice communication, and manufacturers are continually striving to improve wireless equipment to meet the explosive growth.
Radio base stations are one example of continuously improving wireless equipment. Radio base stations are self-contained enclosures that house transmitters, receivers, and other wireless communication equipment. While radio base stations were originally designed for indoor installations, explosive growth has forced manufacturers to design outdoor radio base stations. These outdoor radio base stations allow wireless service providers to improve service by expanding the coverage area.
These outdoor radio base stations, however, are prone to overheating. The wireless communication equipment generates high heat loads within the radio base station. Solar heat loads may also exacerbate internal temperatures within the radio base station. If the wireless communication equipment is exposed to temperatures lying outside an operating range, the equipment may fail from thermal stress. Some radio base stations, therefore, are equipped with air conditioners to keep the wireless communication equipment within the operating range. If the air conditioners fail, the wireless communication equipment overheats and fails. When the wireless communication equipment fails, wireless service is interrupted. An interruption in service irritates customers, disrupts daily business activities, and reduces revenue for the service provider.
Thermal stress is such a concern that some radio base stations have two air conditioners. Air conditioning unit #1 is generally designated a xe2x80x9cleadxe2x80x9d unit, while air conditioning unit #2 is a xe2x80x9clagxe2x80x9d unit. Unit #1 is then the primary cooling unit, while unit #2 is a secondary cooling unit. Unit #1 runs for a preset time and maintains the wireless communication equipment at a preset temperature. Unit #1, for example, may run for twenty four (24) hours and have its thermostat cool to a temperature of eighty degrees (80xc2x0). At the end of the preset time, say twenty four (24) hours, the two air conditioning units swap functions. Unit #2 now becomes the lead primary air conditioner, while unit #1 becomes the lagging secondary air conditioner. This xe2x80x9clead-lagxe2x80x9d operating scenario prevents either air conditioner from continually running and from prematurely wearing out.
The lead-lag operating scenario is also meant to improve cooling of the wireless communication equipment. If the lead air conditioning unit #1 experiences a problemxe2x80x94such as overloading, too much internal heat, or even failurexe2x80x94the lag air conditioning unit #2 then operates as a backup. If unit #1, for example, has its thermostat set at eighty degrees (80xc2x0), unit #2 would initiate cooling if the internal temperature rose to eighty five degrees (85xc2x0). The lag unit thus acts as a backup to the lead unit and helps prevent thermal overloads.
This lead-lag operating scenario, however, does not provide adequate notice of air conditioning failures. A field engineer must know, for example, when the lag air conditioning unit is operating. If the lag unit #2 is operating, then the lag unit #2 may be trying to overcome a heavy heat load. The lag unit #2, worse, may indicate the lead unit #1 has failed. If the lead unit #1 has failed, the lag unit #2 will constantly operate to cool the wireless communication equipment. The lag unit #2, the only working air conditioner, will eventually wear out and fail. The internal temperatures quickly rise, a high temperature alarm trips, and the wireless communication equipment shuts down and causes a communication outage. Only then are the field engineers alerted to the overheating problem. All the while the communication outage is disrupting personal and business activities.
The lack of adequate notice of air conditioning failures cascades to other problems. If the lead unit #1 has failed, and the lag unit #2 continually operates to failure, the wireless service equipment has shut down. Thousands of revenue-generating calls are lost per hour. An air conditioning specialist must be called to investigate the failure. Field engineers must accompany the air conditioning specialist. If the failure occurs on a weekend, a holiday, or an evening, overtime costs apply. Because both air conditioning units have failed, replacement parts, or even replacement units, could cost thousands of dollars. While the air conditioning specialist initiates a repair, the field engineer is setting up floor fans to cool the wireless communication equipment. These fans, however, draw dust and dirt and contaminate the wireless communication equipment. The lack of adequate notice of air conditioning failures, thus, cascades to multiple other problems.
There is, accordingly, a need in the art for a radio base station that has a reduced rate of thermal stress failures, a radio base station that alerts engineers of air conditioning problems or unusual operating conditions, and, yet, a radio base station design that can resolve the prior art problems without extensive revisions or large expenses.
The aforementioned problems are minimized by a radio base station that monitors its air conditioning system. This radio base station continuously monitors the air conditioning system in real-time. The radio base station alerts field personnel, engineers, or any other person when the air conditioning system operates. If the radio base station has two air conditioning systems, operating in the xe2x80x9clead-lagxe2x80x9d scenario, the radio base station may send an alert when either air conditioning system operates. This radio base station design, therefore, can notify personnel when the lagging, back-up air conditioning system operates, possibly indicating a problem with the lead, primary air conditioning system. The radio base station may then alert field engineers before both air conditioning systems prematurely fail.
The radio base station may also alert engineers and field personnel to other indications of the air conditioning system. The radio base station may send alerts indicating normal operation, errors, or even failures in the air conditioning system. The radio base station, for example, may simply communicate whether the air conditioning system is running. The radio base station could also communicate how much electricity is being used by the air conditioning system. If too much electricity is being consumed, the air conditioning system may have encountered an unusual operating condition. The radio base station could also monitor refrigerant pressures within the air conditioning system. A low refrigerant pressure could indicate a leak in a condenser/evaporator coil. The radio base station may monitor ambient temperatures and indicate unusual cold weather operation. If, for example, the air conditioning system is operating during cold ambient temperatures, ice may form on the condenser. The radio base station, in short, may send any status information, fault or error information, alarm information, or any other information useful for monitoring the operation of the air conditioning system.

BellSouth Intellectual Property Corporation


A daisy-chained memory topology wherein, in addition to the prediction of the timing of receipt of a response from a memory module (DIMM), the memory controller can effectively predict when a command sent by it will be executed by the addressee DIMM. By programming DIMM-specific command delay in the DIMM's command delay unit, the command delay balancing methodology according to the present disclosure “normalizes” or “synchronizes” the execution of the command signal across all DIMMs in the memory channel. By predicting command execution timing, the memory controller can efficiently control power profile of all the DRAM devices (or memory modules) on a daisy-chained memory channel. A separate DIMM-specific response delay unit in the DIMM is programmable to provide DIMM-specific delay compensation in the response path, further allowing the memory controller to accurately ascertain the timing of receipt of a response.

The present disclosure generally relates to memory systems and, more particularly, to command delay balancing in daisy-chained memory devices
Memory devices are widely used in many electronic products and computers to store data. A memory device is a semiconductor electronic device that includes a number of memory chips, each chip storing a portion of the total data. The chips themselves contain a large number of memory cells, with each cell storing a bit of data. The memory chips may be part of a DIMM (dual in-line memory module) or a PCB (printed circuit board) containing many such memory chips. In the discussion hereinbelow, the terms "memory device", "memory module" and "DIMM" are used synonymously. A processor or memory controller may communicate with the memory devices in the system to perform memory read/write and testing operations. FIG. 1 illustrates a prior art arrangement 10 showing signal communication between a memory controller 11 and a plurality of memory devices (DIMMs) 12, 18, and 24, over a parallel memory bus 30 (also known as a "stub bus"). For ease of discussion and illustration, only three memory devices (DIMM0 (12), DIMM1 (18), and DIMM N−1 (24)) are shown in FIG. 1 out of a total of N memory devices, which are controlled by and communicating with the memory controller 11. It is observed that also for ease of discussion each DIMM in FIG. 1 is shown to contain the same N number of DRAM (Dynamic Random Access Memory) memory chips. For example, memory module 12 contains a DRAM memory bank 14 having an N number of DRAM chips 16, whereas memory module 18 contains a memory bank 20 having an N number of DRAM chips 22, and so on. However, it is evident that each DIMM in FIG. 1 may contain a different number of memory chips or DRAMs. It is noted here that the terms "DRAM chip," "memory chip", "data storage and retrieval element," and "memory element" are used synonymously hereinbelow.
Each memory chip 16, 22, 28 may include a plurality of pins (not shown) located outside of the chip for electrically connecting the chip to other system devices through the DIMM on which the chip resides. Some of those pins (not shown) may constitute memory address pins or address bus, data pins or data bus, and control pins or control bus. Additional constructional details of a memory chip (e.g., one of the chips 16) are not relevant here and, hence, are not presented. Those of ordinary skill in the art will readily recognize that memory chips 16, 22, and 28 of FIG. 1 are not intended to be a detailed illustration of all of the features of a typical memory chip. Numerous peripheral devices or circuits (not shown) may be typically provided on a DIMM along with the corresponding memory chips for writing data to and reading data from the memory cells (not shown) in the chips. Furthermore, constructional details of a DIMM (e.g., the DIMMs 12, 18, and 24) in FIG. 1 are also not shown for ease of illustration only. In reality, each DIMM may be connected to the parallel bus 30 via appropriate DIMM connectors (not shown) to allow signal flow between the DIMM and the controller 11.
In the parallel bus implementation 10 of FIG. 1, the memory controller 11 sends address and/or control signals over the address/control bus portion (not shown) of the parallel bus 30 and transfers data to/from the DIMMs over the data bus portion (not shown) of the parallel bus 30. The parallel bus 30 is a signal transfer bus that includes address and control lines (both of which are unidirectional) as well as data lines (which are bi-directional)—some or all of which are connected to each DIMM in the system and are used to perform memory data transfer operations (i.e., data transmission and reception operations) between the memory controller 11 and respective DIMMs 12, 18, 24. The memory controller 11 may determine the modes of operation of a memory module (or DIMM). Some of the control signals (not shown) from the memory controller 11 may include a chip select (CS_N) signal, a row address select (RASN) signal, a column address select (CAS_N) signal, a Write Enable (WE_N) signal, row/column address (A), a Data Mask (DM) signal, a termination control (ODT_N) signal, and a set of single-ended or differential data strobes (RDQS/RDQS#/DQS/DQS#), etc. These control signals are transmitted on the control lines or control bus (not shown) portion of the parallel bus 30 to perform data transfer operations at selected memory cells in the appropriate memory chips (DRAMs). The "width" (i.e., number of lines) of address, data and control buses may differ from one memory configuration to another.
It is observed that in the parallel bus configuration 10 of FIG. 1, each memory module 12, 18, 24 is directly connected to the memory controller 11 via the parallel bus 30. In other words, the memory controller 11 is connected to each memory module (DIMM) in parallel. Thus, every signal output from the controller 11 reaches each memory module in parallel. While such an arrangement may be easier to implement and may provide a "wider" memory bus, a penalty to be paid is the limited speed with which signaling can be carried out on the bus 30. In modern implementations of the parallel bus 30, the signaling speed caps at about 800 MHz. Further, in the parallel bus configuration, any delay encountered in the slowest DIMM governs the overall delay in data transfer operations. To increase the signaling speed of memory data transfer operations in the GHz region to avail of the processing power of modern faster memory chips and controllers, the parallel bus configuration may not be suitable.
FIG. 2 illustrates an alternative configuration 32 where memory modules (DIMMs) 34, 40, and 44 are connected to a memory controller 33 in a daisy-chained configuration. As before, only three of the memory modules (out of a total of N modules) are illustrated in FIG. 2 for the sake of simplicity. Also for the sake of clarity, in FIG. 2, a connector for a memory module (the DIMM connector) is identified with the same reference numeral as that of the corresponding memory module. Similar to the embodiment of FIG. 2, each DIMM in FIG. 2 contains a corresponding DRAM memory bank with a plurality of memory chips or DRAM chips therein. For example, DIMM 0 (34) is shown to contain a memory bank 36 with N DRAM chips 38. For the sake of clarity, other memory banks (e.g., memory banks 42 and 46) in FIG. 2 are not shown with corresponding memory chips.
In the daisy-chained configuration 32 of FIG. 2, each DIMM connector 34, 40, 44 has a pair of "downlink" terminals and a pair of "uplink" terminals. Each pair of downlink terminals includes a downlink-in terminal (DL_In) and a downlink-out terminal (DL_Out). Similarly, each pair of uplink terminals includes an uplink-in terminal (UL_In) and an uplink-out terminal (UL_Out). The daisy-chained configuration 32 is a serial signal transfer mechanism as opposed to the parallel mechanism shown in FIG. 1. Thus, a memory module receives a signal from the memory controller 33 on the downlink channel (comprising of all the downlink terminals 48A-48C in the configuration 32), whereas a signal to the memory controller 33 is transmitted on the uplink channel (which includes all the uplink terminals 50A-50C in the configuration 32). Signals are serially propagated from one memory module to another via signal "hops." Thus, for example, a command broadcast to all of the DIMMs 34, 40, 44 from the memory controller 33 is first received at the DL_In terminal 48A of DIMM 0 (34), which, in turn, forwards that command to DIMM 1 (40) via its DL_Out terminal 48B that is also connected to the DL_In terminal of DIMM 40. This completes one command "hop". After a second command "hop", the command from the memory controller 33 appears at DL_Out terminal 48C of the memory module 40. Thus, with a total of N−1 "hops", the command will reach the last or farthest DIMM (here, DIMM 44) in the memory channel (which consists of all memory modules connected to the memory controller 33 in the daisy-chained configuration 32). Similarly, an N−1 "hops" may be needed for a response to the command from the last or farthest DIMM 44 to reach the memory controller 33. It is noted here that the term "command" is used herein to refer to address, data, and/or control signals transmitted from the memory controller (e.g., during a data write operation, or during a memory module testing operation) to one or more DIMMs in the system 32. On the other hand, the term "response" is used herein to refer to a data or a status signal (e.g., during a data read operation, or during a memory test operation) sent to the memory controller 33 and generated by a DIMM in response to the command received from the memory controller 33.
As is seen from FIG. 2, in a daisy-chained memory configuration, the memory controller 33 is directly connected to only one of the DIMM modules (i.e., the memory module 34 in FIG. 2) as opposed to all of the memory modules as in the parallel bus configuration of FIG. 1. Thus, one disadvantage of the serial daisy-chaining is that a defect or malfunction at one of the memory modules may prevent further "downstream" propagation of the command from the memory controller 33. However, despite this disadvantage, the daisy-chained configuration 32 offers significant benefits including, for example, very high speed signal propagation (in the range of multi-GHz) and more control over individual DIMM's data transfer operations. Thus, the signaling in the daisy-chained configuration 32 can be significantly faster than that in the parallel configuration 10. As noted before, each DIMM in the daisy-chained configuration acts as a "repeater" of the signal for the next DIMM-downstream (connected to the DL_Out terminal) or upstream (connected to the UL_Out terminal). The downlink and uplink channels are extremely fast, narrow-width, unidirectional (one-way) signal buses that carry encoded signal packets (containing memory address, data, and/or control information from the memory controller 33) which are decoded by the receiver DIMM. The downlink channel carries signal in one direction, whereas the uplink channel carries a different signal in the opposite direction. It is evident that in the daisy-chained configuration 32 of FIG. 2, a signal must travel through "hops" whether it is a signal broadcast from the memory controller 33 to all of the DIMMs in the memory channel, or whether it is a signal addressed to only a single DIMM in the memory channel. That is, any signal from the memory controller 33 propagates to the desired/destination DIMM(s) via one or more hops involving one or more intervening DIMMs.
It is noted here that the term "daisy-chained configuration" is used herein to refer to a high-speed, serial bus configuration and, more particularly, to a serial bus configuration linking a plurality of electronic devices (e.g., memory modules 34, 40, 44 in FIG. 2) with a controller thereof (e.g., the memory controller 33 in FIG. 2) using unidirectional signal transfer links, where the set of links or terminals (the downlinks) carrying signals out of the controller is different from the set of links (the uplinks) that carries the signals to the controller.
From the foregoing discussion, it is seen that in the daisy-chained configuration 32 of FIG. 2, a signal encounters varying amounts of delay before reaching a destination DIMM or the memory controller 33. For example, the DIMM 44 may receive a signal transmitted from the memory controller 33 after a specific delay has elapsed, wherein the delay would include the time consumed by N−1 hops needed before the signal can reach DIMM 44. On the other hand, in case of DIMM 40, the signal may get delayed only by the time taken to conclude a single hop (through DIMM 34) to reach DIMM 40. In the event of a response generated by a DIMM, the delay for the response to reach the memory controller 33 also varies depending on the "depth" of the memory channel. For example, a response generated by DIMM 0 (34) may reach the memory controller without any "hops", whereas a response from the DIMM 44 may need to go through N−1 hops before reaching the memory controller 33. Thus, the amount of delay may linearly vary with the physical proximity of a memory module 34, 40, 44 to the memory controller 33 (i.e., the farther the memory module, the higher the delay), and may also linearly vary with the total number of memory modules in the memory channel (i.e., the more the number of memory modules serially connected to the controller 33 in the daisy-chained manner, the higher the delay for the farther modules).
It is seen from the above discussion that in the daisy-chained configuration 32 of FIG. 2, a command from the memory controller 33 may be processed by different DIMMs at different times because of the inherent command propagation delay through "hops." Similarly, responses from different DIMMs may arrive at different times at the controller 33, again because of the delays through "hops." In the embodiment of FIG. 2, the command delay or command propagation delay (i.e., the total delay for a command or signal from the memory controller 33 to reach the farthest DIMM 44) must be accounted for along with the response delay or response propagation delay (i.e., the total delay for a response from the farthest DIMM 44 to reach the memory controller 33) so as to assure that a response from any DIMM in the system 32 reaches the memory controller 33 at the same time. This effect may be called "delay levelization", i.e., the memory controller 33 need not wait for varying amounts of time to receive responses from various DIMMs in the system 32. Instead, a fixed, predetermined time delay is all that is required for the memory controller 33 to wait for in expecting a reply from any DIMM in the system 32. Thus, from the memory controller's perspective, only a fixed, single delay exists between sending a command and receive a response, irrespective of the depth of the memory channel or the physical proximity of a DIMM to the memory controller 33. This aspect is similar in principle to the latency in the parallel bus configuration of FIG. 1. As noted before, in case of FIG. 1, the delay of the slowest DIMM may govern the latency experienced by the controller 11 between a command and the receipt of its response from a DIMM in the system 10. In case of the daisy-chained configuration 32 of FIG. 2, it is similarly desirable that the controller 33 be freed from making latency determinations on a case-by-case basis for each DIMM. Instead, the delay may be "levelized" so that the controller 33 may receive (or "expect") a response from any DIMM 34, 40, 44 at the same time.
FIG. 3 illustrates a prior art methodology to achieve delay levelization in the daisy-chained memory channel of FIG. 2. In FIG. 3, constructional details to achieve delay levelization are illustrated for only one of the DIMMs (i.e., DIMM 1 (40)) in the system 32 in FIG. 2. However, it is evident that a similar configuration may be present on each DIMM 34, 40, 44 in the system 32. The DIMM 40 in FIG. 3 is shown to include a DIMM-specific response delay unit 52, which allows a programmable delay to be stored therein. The amount of delay to be programmed in the delay unit 52 may primarily depend on three factors: (1) the physical proximity of the DIMM 40 to the memory controller 33, (2) the total number of DIMMs in the daisy-chained configuration 32, and (3) the total of the command propagation delay to the farthest DIMM in the system (e.g., the DIMM 44 in FIG. 2) and the response propagation delay from the farthest DIMM to the memory controller 33. For example, for simplicity and illustration, assume that there are only three DIMMs (DIMMs 34, 40, and 44) in the system 32 of FIG. 2 and there is one clock cycle of "hop-related" delay for each of the command and response propagations at each DIMM in the system 32 (except the farthest DIMM 44, as discussed below). That is, it is assumed that it takes one clock cycle of delay to propagate a command signal to the next downstream DIMM over the downlink channel, and it also takes one clock cycle of delay to propagate a response signal to the next upstream DIMM over the uplink channel—i.e., a symmetrical delay in uplink and downlink channels. In that case, ignoring very small signal processing delays (to process a command and to generate a response) by the DRAM memory bank 42, the delay unit 52 in FIG. 3 may be programmed to appropriately delay transmission of the response (which may contain the data to be read) generated by the memory chips in the memory bank 42 to the command from the memory controller 33.
In the present example, the amount of delay to be programmed in the delay unit 52 equals [T*(N−1)/P] clock cycles, where "T" is the total "hop-related" clock cycle delay at a DIMM (except the farthest DIMM 44, as discussed below) including the delays to propagate a command to the next "downstream" DIMM and a response to the next "upstream" DIMM in the daisy chain (T=2 in the present example), "N" is the total number of DIMMs in the system (here, N=3), and "P" is the physical proximity of the DIMM to the memory controller 33 (e.g., P=1 for the first or closest DIMM 34, P=2 for the second downstream DIMM 40, and so on). Therefore, in the case of DIMM 1 (40), the value of delay to be programmed in the unit 52 is equal to 2 clock cycles, whereas the value of delay to be stored in the corresponding delay unit (not shown) in the DIMM 0 (34) is 4 clock cycles. In case of the farthest DIMM (i.e., the DIMM 44 in FIG. 2), the value of programmable delay may be zero because T=0 for the farthest DIMM.
It is seen from the foregoing that the levelization discussed with reference to FIGS. 2 and 3 allows the memory controller 33 to receive a response from any memory module in the daisy-chained configuration 32 at the same time. With the use of appropriate delays at each DIMM in the system 32 to compensate for the time consumed in propagation of command and response signals to/from the farthest DIMM in the daisy chain, the memory controller 33 receives a response from each DIMM at the same time, regardless of the physical proximity of the DIMM with respect to the controller 33. That is, the controller 33 "expects" and receives the response after a fixed delay has elapsed from the transmission of the command by the controller 33 over the downlink channel, regardless of whether the command is sent to a single DIMM or broadcast to all DIMMs in the system. For example, if a command is sent at time "t", then in the case of the previous example, the memory controller 33 receives a response 4 clock cycles after "t", regardless of whether the command is sent to DIMM0(34) or to DIMMN−1 (44).
It is observed with reference to the embodiment of FIG. 3 that the dotted lines are shown in FIG. 3 to illustrate how a signal propagates within the DIMM 40. Thus, for example, a command signal appearing at DL_In terminal 48B would directly propagate to the DL_Out terminal 48C to be sent to the next downstream DIMM. That command signal would also be sent to the DRAM memory bank 42 for processing (e.g., data writing to memory cells). On the other hand, a response signal appearing at the UL_In terminal 50C from an adjacent ("upstream") DIMM would similarly be propagated directly to the UL_Out terminal 50B. The DIMM 40 may add its own response (appropriately delayed through the delay unit 52 as discussed hereinbefore) with the signal received at the UL_In terminal 50C so as to also send its response along with the previous DIMM's response to the next DIMM in the uplink channel.
Despite streamlining or "normalizing" the delivery of responses from DIMMs to the memory controller 33, the embodiment of FIG. 3 still leaves the memory controller 33 unable to predict when a command will be executed by a specific DIMM. It may be desirable, especially in some DRAM operations, for the memory controller 33 to predict the execution of the commands by addressee DIMMs so that the controller 33 can control the memory system power consumption (or power profile) with better certainty and/or more easily. For example, some DRAM operations, such as a "Refresh" command, may consume a lot of power. In the embodiment of FIG. 3, the memory controller 33 may spread out the DIMM-specific refresh commands over time to try to reduce drawing too much system power, i.e., to try to avoid sudden surges in power consumption when two or more DIMMs simultaneously execute their corresponding refresh commands. Thus, in the case of only three DIMMs (e.g., DIMMs 34, 40, 44), the memory controller 33 may send a refresh command to the farthest DIMM 44 on the first clock cycle, then a second refresh command to the middle DIMM 40 on the second clock cycle, and a third refresh command to the closest DIMM 34 on the third clock cycle. However, despite such spreading out of refresh commands, it may happen that DIMMs 40 and 44 end up executing the refresh command at the same time, which may not be preferable. Or, even if such simultaneous processing of the refresh command is tolerated, it may still be desirable for the memory controller to "know" when the commands will be processed by recipient DIMMs.
Therefore, it is desirable to devise a system wherein, in addition to the prediction of the timing of receipt of a response from a DIMM, the memory controller can effectively predict when a command sent by it will be executed by the addressee DIMM. With such ability to predict command execution timing, the memory controller can efficiently control power profile of all the DRAM devices (or memory modules) on a daisy-chained memory channel.

Memory command delay balancing in a daisy-chained memory topology


An array substrate structure of a display panel includes a substrate, a plurality of first wirings, a first patterned insulating layer, a plurality of second wirings, a plurality of first protective patterns, and a plurality of second protective patterns. The substrate has a wiring region. The first wirings are disposed in the wiring region. The first patterned insulating layer is disposed on the first wirings. The second wirings are disposed on the first patterned insulating layer. The first protective patterns are disposed in the wiring region and disposed on the corresponding second wiring, respectively, where the first protective pattern includes a semiconductor material. The second protective patterns are disposed on the corresponding first protective pattern, respectively, where the second protective pattern includes an inorganic insulating material.

1. Field of the Invention
The present invention relates to an array substrate structure of a display panel and method of making the same, and more particularly, to an array structure of a display panel and the method of making the same that is able to prevent wirings in the wiring region from being damaged during fabricating process.
2. Description of the Prior Art
A substrate of an array substrate structure of a display panel is typically defined to a display region, a wiring region, and a pad region. Gate lines, data lines, pixel arrays, and thin film transistors (TFTs) are disposed in the display region. Wirings for electrically connecting the gate lines and the data lines to the pad region are disposed in the wiring region. And the pad region provides electrical connection between the gate lines/the data lines and a driving chip or a circuit board. Accordingly, driving signals from the driving chip or the circuit board are provided to the gate lines and the data lines through the wirings.
Conventionally, etching processes for defining conductive layers, semiconductor layers, dielectric layers, and protecting layers are required for fabricating the array substrate structure of the display panel. However, it is found that the pre-layer exposed by the specific material layer being etched is unavoidably damaged. For example, the wirings under the protecting layer are often damaged during etching the protecting layer. Consequently, yield of the array substrate structure of the display panel is adversely impacted and thus cannot be improved.

Array substrate structure of display panel and method of making the same


The disclosure involves a valve for a brass instrument, e.g., a trombone, having an outer casing and a rotatable piston with first and second outer passages and a central passage between the outer passages. Two pairs of tubes are connected to the casing with each tube of a pair being coextensive with the other tube of that pair. At least one and preferably each outer passage is coextensive with a pair of tubes when the piston is in the switched position. The valve thereby affords "straight through" air flow during that valve position at which the trombone air column is longer or longest. Air flow resistance is thus reduced and the musician experiences a better "feel" when playing lower register notes, particularly when doing so at increased volume. A method for making the new valve, which is substantially hollow and lightweight, is also disclosed.

It has been common knowledge for centuries that air columns of differing length produce musical notes of differing pitch. An example of an instrument based upon this principle is a pipe organ. Such organs have a multiplicity of pipes of varying lengths (as well as diameters) but the length of a particular pipe (and the air column therein) does not change.
Other examples include cornets and trumpets which use linearly-actuated valves and French horns which use rotary valves, all to change the note(s) produced by the instrument. In these latter examples, such note changes are by valving tubing of various lengths into or out of the air column "circuit," thus changing the length of the air column as measured from the instrumentalist's lips to the bell from which sound is emitted.
Trombones and tubas are yet other examples of instruments producing different notes by changing the air column length. A trombone uses a telescoping handslide to change the length of the air column. And many trombones (often referred to as slide trombones) use only a handslide for that purpose.
(By way of parenthetical background, it should be appreciated that the lower the note being played with, for example, a trombone, the longer is the air column and the more difficult it is for the musician to achieve "volume" in the note being played. This is so because the longer air column creates increased resistance to air passage.)
A feature of a slide trombone is that the handslide must often be manipulated very rapidly between notes. And, sometimes, it must be manipulated quickly over a relatively great distance as, for example, when playing a higher note (at which time the handslide is close to the musician's face and fully telescoped or nearly so) followed immediately by a low note requiring the handslide to be extended well away from the musician.
To help reduce the time required to play certain sequential notes, rotary valves have been developed to switch one or more lengths of tubing into and out of the instrument air column. This quickly effects a change in air column length (and, therefore, a note change) by valve manipulation rather than by handslide manipulation.
It is believed that the first rotary valve was invented in about 1832 by one Mr. Joseph Riedl of Vienna, Austria and in any event, disc-shaped rotary valves have been in wide use since at least as early as the late 1930's. Such valves are mounted on the instrument so that a flat, circular surface is toward the musician's cheek and does not interfere with or touch the musician's cheek.
Although rotary valves solved one problem, they were attended by new problems. For example, common disc-shaped rotary valves have pieces of tubing (those switched into and out of the circuit by the valve) fastened to the valve casing generally radially and using rather sharp bends. And the internal valve passages themselves involved some rather sharp bends. These "convolutions" in the air flow path add yet additional resistance to the musician's "blowing power." Thus, they not only further limit the maximum volume that a musician can obtain, they also have some undesirable effect on tonal quality.
Yet another difficulty with known rotary valves is that even though the stationary tubing attached to the valve casing is circular in cross-section, the passages in the rotating valve piston are often ellipsoid (or, perhaps of some other shape) but not circular. As a result, there is an abrupt flow discontinuity where the non-circular passage and the circular tube intersect. The tonal quality of the instrument is thereby adversely affected. Such a valve is said to lack "flow tangency."
The currently-available Model YSL-682B trombone, made by Yamaha Corporation, includes an example of a rotary valve which (in addition to being ill-suited for two-valve instruments) lacks flow tangency. The stationary tubing attached to the valve is circular in cross-section but the passage through the valve piston is distinctly D-shaped.
And the tubing attached to the valve casing not only includes at least one rather sharp bend adjacent to the casing, such tubing "wraps" over an arc of about 270.degree. and introduces added resistance to air flow. A bend in such tubing protrudes from the bottom of the instrument and uncomfortably into the shoulder of the musician.
Further, the Yamaha valve introduces two bends in each of two air flow passages when the valve is in the switched position for playing lower notes. Since the switched position provides a longer air column, these bends introduce flow resistance at that time when the musician is least able to tolerate them and overcome their resistive effect. Like the Thayer valve discussed below, the Yamaha valve is a relatively new design introduced in an effort to resolve some of the shortcomings of earlier valves.
A few years ago, a rotary valve known as the Thayer valve was introduced, apparently to help overcome the problem of lack of flow tangency. The Thayer valve uses a cone-shaped rotating piston with an air entry passage at the apex end. The air exit passage terminates at the cone base (as does another passage in this two-passage valve) and such terminations are spaced radially outward from the cone center axis through the apex end and perpendicular to the base.
A difficulty with the Thayer valve is that at that portion of the valve adjacent to the base of the piston, the valve is quite thick and usually (and annoyingly) contacts the musician's cheek. In fact, it is not an exaggeration to say that the valve sometimes uncomfortably "digs into" the musician's cheek.
Still another difficulty with the Thayer valve involves the matter of valve lubrication. In professional use, trombone valves are usually lubricated daily. To lubricate the Thayer valve, one must substantially disassemble the instrument and this is annoying and time-consuming.
Still another difficulty with conventional rotary valves involves the matter of weight. The starting material for the rotating pistons of known disc-shaped rotary valves is a solid bar or rod of brass. Passages are milled or otherwise formed in the rod.
A new rotary valve for brass instruments (and method for making such a valve) which offers straight-through flow passages, which does not interfere with the musician's person, which uses only gradual bends and which is light in weight would be an important advance in the art.


An improved housing for a rolled-ribbon electrochemical device is provided. The housing comprises a fastener that aligns first and second cups during assembly and maintains electrode contact independent of external pressure on the housing eliminating the possibility of an open circuit state for a cell. In one alternative embodiment, the fastener comprises a stem that fits into a hollow tube and resists detachment from the tube. In another alternative embodiment, the fastener comprises a stem that fits into a grommet and resists detachment from the grommet. In yet another alternative embodiment, the fastener comprises a tube that fits into a grommet and resists detachment from the grommet.

With the increasing pace of advances in electronics there has been a corresponding increase in the need for electrochemical devices that safely and efficiently provide sufficient energy density to power advanced electronic devices, especially portable electronic devices, while still being economically viable. Older battery configurations are often unsuitable to meet these increased demands. Out of environmental and efficiency concerns, the reach of electricity providing devices has been expanded to new areas including hybrid electric vehicles. Ideally, an electrochemical device will provide high current density, decrease the internal resistance of the battery, and effectively manage the thermal output of the electrochemical device to increase the longevity of the device. These features can be achieved by providing massive and/or large surface-area connections between electrodes and cell current collectors, and specifically between cells in a battery.
A second important feature of the high power device is internal heat removal. Thermal management is important to the long life of Li-ion batteries in retaining battery capacity particularly due to electrolyte degradation. High power to external circuitry generally generates a like amount of energy as heat over a short time duration and internal to the cell. Excessive temperatures will destroy (e.g. melt the microporous polymer separator or autoignite the flammable organic electrolyte) or significantly shorten the useful life of the Li-ion cell. Under high pulse power, heat is generated at the electrode/separator interface due to limited ionic conduction. For the conventional jelly-rolled cell, the most direct path for heat loss is across the layers of heat sensitive microporous polymer. Excessive temperature within the cell will locally shutdown the microporous polymer resulting in still higher temperatures possibly leading to the auto-ignition of the organic electrolyte.
An electrochemical device comprised of cathode and anode electrodes physically exposed to an electrolyte can generically be used to convert between chemical and electrical energies. A housing can enclose these electrode and electrolyte components, and can even seal them from the atmosphere. Batteries, fuel cells, and capacitors are but a few such specific electrochemical devices to which this invention relates.
As the electrical power in terms of voltage and/or amperage of each pair of cathode and anode electrodes (or cell) is generally small, many separate pairs of cathode and anode electrodes or cells can be used in a single housing. Current collectors are generally used to electrically interconnect the cells, in parallel and/or in series, to provide usable voltage and amperage outputs at exposed terminals on the electrochemical device.
The electrochemical device performs usable work when ions pass between the electrodes of each cell via the electrolyte, and when electrons concurrently pass through each cell via the electrodes. The generated voltage per cell is predetermined by the electrochemical reaction of the component materials used, and the generated amperage and/or power available is dependent on the configurations and masses of these active components.
The specific output energy of the device can be provided in terms of watts-hours per device weight, and the specific output power of the device can be provided in terms of watts per device weight. Output values of existing electrochemical devices are typically small fractions of theoretically possible output values because of internal resistances and other inefficiencies (hardware mass and volume).
The resistance to ion conduction between the electrode elements is one major source for internal power loss. Such resistance, R, can be theoretically determined with the expressionR=ρI/A. where:                "ρ" (rho) is the impedance value of the electrolyte;        "1" is the thickness of the electrolyte; and        "A" is the interfacial contact area between the electrode elements and electrolyte.
The ionic-impedance value, ρ, is not easily subject to modification and is not effective as a design parameter. Designers of electrochemical devices thus strive to reduce the electrolyte thickness "I", and to increase the interfacial contact area "A" between the electrode elements and the electrolyte.
Different configurations of the cathode and anode electrodes, of electrolyte separation, and of current collection have been proposed. For example, a cathode electrode band can be zig-zagged to define separate compartments for holding the electrolyte, and inserted with elongated rod-like anode electrodes into the electrolyte spaced from the cathode electrode. The interfacial contact area "A" effectively is less than the overall surface area of the anode rods, as some rods oppose one another rather than the cathode.
Also, a zig-zagged, folded separator band can define opposing compartments for holding and isolating plate-like cathode and anode electrodes, with electrolyte engulfing all of these components. In an alternative design, each cell can be formed with C-shaped electrodes and a Z-shaped separator sandwiched therebetween. Alternatively, a separator band having electrically conductive surfaces can be folded and sandwiched between separate sets of respective plate-like cathode and anode electrodes placed between the separate oppositely facing folds. A "jellyroll" cell can be formed by coiling a preformed assembly of cathode and anode electrodes and a separator on itself to yield a cylindrically shaped electrochemical device, wherein the face-to-face electrodes and sandwiched electrolyte and separator structures increase the interfacial contact area "A" between the electrodes. However, the very breadth of the facing electrodes and sandwiched electrolyte and separator raise another issue, namely the sufficiency of the structure in maintaining and in supporting the electrode elements physically separate during assembly and during operation. This includes withstanding thermal expansion and contraction forces of the cell components during operational temperature changes. Increasing the thickness of the sandwiched electrolyte and separator to provide needed strength and/or durability also increases the ion-conducting electrolyte thickness "I", offsetting benefits obtained by increased interfacial contact area "A".
Current collectors used in these cell arrangements add significant weight, and thus reduced specific cell energy and power outputs. For example, isolated conductors are generally connected to the electrodes and routed along extended paths independently of the electrodes to the external terminals. These conductors should carry the full cell current, and thus should be of sufficient mass and cross-section to keep internal resistance manageably low. For a typical battery design of connected terminals, electrode tab/current collector/cell terminal resistance/battery terminal resistance can account for a 50% reduction in battery power output from theoretical capability. Generally, massive connectors are used to avoid power loss for high powered batteries.
Additionally, these cell arrangements provide electrodes of limited size and/or thickness, limiting the quantities of usable electrode materials, and thus, limiting maximum cell storage energy and/or operating cycle-life, particularly for rechargeable cells.
The dilemma of these designs is that power gains obtained by increasing the interfacial electrode area "A" across the electrolyte generally are typically offset by increased electrolyte thickness "I" and that the weight and volume of the current collectors reduce specific energy and power outputs. Power can be increased, but only at the expense of reduced energy storage capacity per weight and volume and at increased cost due to needed additional hardware. High interfacial area "A" of the spirally wound "jellyroll" configuration merely trades off usable power against the energy density because a minimum separator thickness is needed for cell durability and cycle-life. Existing bipolar cell arrangements do not escape this power and energy trade off dilemma; nor do fuel cell electrochemical devices.
The rolled-ribbon cell technology disclosed in U.S. Pat. No. 5,219,673 has made great strides towards achieving enhanced power density for electrochemical devices. Specifically applied to Li/organic-based electrolyte chemistries, improved batteries are formed using stackable disk-shaped cells to realize near optimum power capability from the cells. Further objectives of batteries for high-pulse power requirements, such as for hybrid electric vehicles and for power tools, are to continue to reduce battery cost and to increase durability. These Li/organic-based electrolyte battery chemistries, although exhibiting quite high voltages (3-5 volts), have relatively low current density capabilities. One limiting factor is the attempted use of relatively-thin components, i.e. the electrode and separator layers. A practical device generally, requires a lot of active area. For example, with peak current density of 10 mA/cm2, it can require 1000 cm2 active area to achieve 10 A. For hybrid electric vehicles, the current is on the order of 100 A at 200-400 volts (equivalent to 20-40 kW).
Thus, a further dilemma is the large number of small cells that form such batteries. Internal heat generation resulting from the large numbers of small cells (e.g. 1 Ampere-hour (Ah) capacity uses 18,650 cells) is a major power loss source. More recently, larger cells (10 Ah) have used a prismatic configuration. These cells have broad electrodes with multiple tabs connected to a traditional terminal connection. These prismatic cells are hard-wired together (terminal-to-terminal) in a rectangular box. Nonetheless, this arrangement of substantially larger cells can still sacrifice 50% of the theoretical power of the cell chemistry. Thus, there is a continuing and persistent need for electrochemical devices which have high energy density, provide high power output, and approach the theoretical limit for electrical power output.
A Li/organic-based electrolyte battery for high power applications, such as for hybrid electric vehicles, should also incorporate features to enhance safety and battery longevity. Because there is internal gas pressure generated during battery operation and during battery degradation conditions, there needs to be non-catastrophic, cost effective means to relieve the gas pressure. The typical means is to include a rupture disc on the housing of the Li-ion cell. Rupture of a disc housing causes irreversible failure of that battery, and, if a disc ruptures, electrolyte may escape to further degrade the battery. Additionally, because the electrolyte batteries often operate in environments that cause both shock to and vibration of the battery, the battery should be durable.


The invention relates to a magnet valve having a valve body, in which at least one inlet conduit and/or at least one outlet conduit of the magnet valve is provided in at least some regions in the valve body. The inlet conduit and/or outlet conduit are in fluidic communication with a valve seat of the magnet valve. According to the invention, the valve body is provided with a receptacle region, in which an insert part embodying the valve seat is disposed. The invention also relates to a driver assistance system having such a magnet valve.

1. Field of the Invention
The invention relates to a magnet valve having a valve body, in which at least one inlet conduit and/or at least one outlet conduit of the magnet valve is provided in at least some regions in the valve body, and the inlet conduit and/or outlet conduit are in fluidic communication with a valve seat of the magnet valve. The invention also relates to a driver assistance system.
2. Description of the Prior Art
Magnet valves of the type defined at the outset are known from the prior art. They are used for instance for ABS, TC or ESP systems. Typically, they are magnet valves with a radial oncoming flow that are closed when without current and are continuously variable. However, still other embodiments of the magnet valve are feasible, for instance being open when without current. The magnet valve has the valve body. The valve body can additionally be surrounded in at least some regions by a housing or can form the housing of the magnet valve. In the valve body, the inlet conduit and the outlet conduit are embodied at least in some regions. The inlet conduit or the outlet conduit is in fluidic communication with the valve seat of the magnet valve. Typically, the valve seat is embodied in the vicinity of a fluid chamber which is present in the valve body. The valve seat is closable by means of a sealing element. The sealing element can preferably be shifted in the axial direction and is disposed in at least some regions in the fluid chamber. The sealing element can assume at least one closing position and one opening position. In the closing position, the sealing element is disposed on or in the valve seat in such a way that there is no fluidic communication between the inlet conduit and the outlet conduit of the magnet valve. Conversely, if the sealing element is shifted at least partly in the direction of its opening position, fluid can flow through the valve seat, so that the fluidic communication is established. Typically, the valve seat is associated with the inlet conduit. The fluid is thus delivered to the magnet valve through the inlet conduit, or an inlet port associated with the inlet conduit, and carried as far as the valve seat. If the valve seat is opened by the sealing element, and thus the sealing element is in its opening position, then the fluid, through the valve seat, can reach the fluid chamber. Next, the fluid flows through the at least one outlet conduit, which is in permanent fluidic communication with the fluid chamber, and out of the fluid chamber. An outlet port of the magnet valve is associated with the outlet conduit. Often, at least the vicinity of the valve body where the valve seat is located is embodied as an integrated component. This means that in this region of the valve body, both the valve seat and still other geometric properties of the valve body must be designed. This makes the production of the valve body complicated and expensive.

Magnet valve and driver assistance system


A body implantable cardioversion/defibrillation device includes an electrically conductive lead, three lead extensions coupled to the lead through a junction body, and an electrode array consisting of three electrodes, one electrode being coupled to each of the lead extensions. Each electrode has several separate electrically conductive paths, including a primary conductor in the form of a helically wound coil, and a linear shunt conductor in the form of a cable surrounded by the primary coil. The shunt cable is a composite, including a DBS core surrounded by an insulative coating. A dielectric sheath surrounds the shunt cable, preventing the cable from contacting the primary coil and isolating the shunt cable from contact with body tissue or body fluids. At each end of each electrode is a connector structure including a shunt connector attached to an end of the shunt cable, and an outer coil connector surrounding an end of the primary coil and the shunt connector. Both connectors are crimped to maintain the electrical and mechanical coupling. The junction body includes an electrically conductive plate having several bores directed inwardly into the plate. A thin wall portion on one side of each bore can be crimped following insertion of each lead or lead extension, to secure the electrical and mechanical connection.

The present invention relates to electrical defibrillation, including cardioversion, and more particularly to body tissue stimulation electrodes, implanted subcutaneously in the thoracic region, for delivering cardioversion/defibrillation pulses.
Defibrillation is a technique employed to counter arrhythmic heart conditions including tachycardias, flutter and fibrillation of the atria and/or the ventricles. Typically, electrodes are employed to stimulate the heart with electrical impulses or shocks, of a magnitude substantially greater than pulses used in cardiac pacing. One approach to defibrillation involves placing electrically conductive paddle electrodes against the chest of the patient. During cardiac surgery, such paddles can be placed directly against the heart to apply the necessary electrical energy.
More recent defibrillation systems include body implantable electrodes. For example, patch electrodes can be applied directly to epicardial tissue. Electrodes can be placed at the distal end region of an intravascular catheter inserted into a selected cardiac chamber. U.S. Pat. No. 4,60,705 (Speicher et al) discloses an intravascular catheter with multiple electrodes, employed either alone or in combination with an epicardial patch electrode. Compliant epicardial defibrillator electrodes are disclosed in U.S. Pat. No. 4,567,900 (Moore), and in U.S. Pat. No. 5,105,826 (Smits et al).
Epicardial electrodes are considered efficient in the sense that less pulse generator energy is required for delivering effective defibrillation pulses. However, epicardial electrode implantation typically requires highly invasive major surgery including entry of the chest cavity, typically involving the spreading of adjacent ribs or splitting of the sternum, presenting a risk of infection. Epicardial electrodes must either be quite small, or highly compliant and resistant to fatigue, as they must maintain a conformal fit to the epicardium.
Larger defibrillation electrodes usually are preferred, since increasing the electrode size reduces impedance at or near the electrode. Sensing artifacts also are reduced. However, the larger electrodes are more difficult to attach to the epicardium and are more subject to fatigue, as they must conform to the heart during contractions associated with normal cardiac activity.
Subcutaneous defibrillation electrodes are easier to implant, and the implant procedure involves less risk to the patient. To achieve a large effective electrode area and yet maintain patient comfort to the extent possible, defibrillation can be accomplished with an array of several electrodes or electrode segments spaced apart from one another, as disclosed in U.S. Pat. application Ser. No. 07/533,886 filed Jun. 6, 1990, assigned to the assignee of this application. The electrode segments are relatively long and narrow, and are coupled to a single electrically conductive lead for simultaneous delivery of the defibrillation pulse. The electrode segments are highly compliant, and can be formed of composite conductors in the form of titanium or tantalum ribbons or wires, or a cable consisting of a silver core in a stainless steel tube. In either case, an outer layer of platinum can be applied by sputtering, or cladding after applying a Tantalum layer for adhesion. A braided construction also can impart compliance to an elongate electrode or electrode segment, as disclosed in U.S. Pat. No. 5,005,587 (Scott).
In view of the greater efficacy of large effective shocking area electrodes, longer electrodes and electrode segments are preferred. However, as an electrode of a given diameter becomes longer, its impedance increases, as does the voltage drop from the electrode proximal end to the electrode distal end. This leads to an unwanted gradient in interelectrode current distribution. Typically the conductive path is substantially longer than the linear length dimension of the electrode, because of the common practice of configuring electrodes as helically wound coils to enhance their fatigue resistance and ability to continually conform to body tissue. Of course, the diameter of the strand forming the coil electrode can be increased to improve its conductivity. However, this also increases electrode stiffness and patient discomfort. A further constraint arises from the fact that the electrode is in surface contact with body tissue. Accordingly, electrode materials must be body compatible as well as electrically conductive. Certain materials with highly favorable conductivity and fatigue properties are unavailable for use in such electrodes.
Therefore, it is an object of the present invention to provide an elongate electrode that is highly conductive in spite of a relatively small diameter and lateral cross section.
Another object is to provide a body implantable tissue stimulating electrode of considerable length, yet substantially uniform in potential (voltage) level from its proximal end to its distal end.
A further object is to provide an electrode structure incorporating a primary conductive path in contact with body tissue, and a conductive shunt path with a fluid tight sealing means preventing the shunt path from contacting body fluids or body tissue.
Yet another object is to provide a cardioversion/defibrillation electrode array having a high degree of redundancy.


A wallbase molding strip is provided with a vertical back portion and a skirt portion extending outwardly and downwardly from a front surface along a first line intermediate the upper and lower edges of the back portion, and a self-hinge in the form of a longitudinal recess located for the full length of the strip on the back of the strip below the skirt portion. The self-hinge functions to permit the strip to be selectively used either with a bottom part in a vertical position for placement over thick flooring material or with the bottom part in a forwardly folded position for placement over thin flooring material.

In laying carpet, linoleum or other flooring materials, it is customary to use a finishing member at the intersection of the flooring material with a wall for hiding the raw edges of the flooring. Finishing members in the form of elongated flexible coves or molding strips of rubber, linoleum, polyvinylchloride or similar resilient materials, providing a vertical back portion that abuts the wall and an outwardly and downwardly extending skirt or flange portion that provides a smooth concave transition to the flooring, are well known. Examples of such molding strips are set forth in U.S. Pat. Nos. 2,300,084; 3,549,471; and 3,638,374. Such moldings ordinarily come with the skirt portion that overlays the flooring either connected at the bottom of the base portion in the manner of a flexible toe (see, e.g., U.S. Pat. No. 2,300,084) or connected integrally at an intermediate point of a front surface of the back portion (see, e.g., U.S. Pat. No. 3,638,374).
In laying conventional thin flooring materials, such as 1/8" to 1/4" linoleum tile or sheet flooring, wallbase molding strips are often applied after the flooring so that the skirt portion presses down onto the flooring at a feathered leading edge a slight distance away from the wall. However, because later application of the base risks damaging carpet with adhesive, conventional carpet practice is to apply the wallbase molding before installation of the carpet. This necessitates either proper positioning of a bottom end skirt member above the level of the floor, or the use of the intermediate located skirt-type molding strip, so that the carpet edge can be securely and snugly tucked under the molding strip skirt. Intermediate located skirting strips are not useable for both carpeting and thinner flooring because of the variation in thickness of the materials. Carpeting requires approximately 1/2" clearance below the leading edge of the skirt and the floor under which to tuck a carpet; linoleum flooring requires only a 1/4" clearance. Accordingly, different molding strip configurations have been developed for thinner flooring and thicker flooring.


A test equipment pin driver having a main output channel including a pulse forming circuit, a buffer and an output amplifier connected in series. The pulse forming circuit provides pulses that are timed to a data input signal, and the buffer passes the pulses to the amplifier which produces driver pulses adapted to be transmitted to a device under test. The high and low voltage levels of the driver pulses are made substantially the same as programmed high and low voltages by providing scaled replicas of the buffer and amplifier, and using closed loop compensation to accurately drive the replica outputs to the high and low programmed voltages, respectively. The replicas mirror the DC performance of the buffer and amplifier of the main output channel, and clamping voltages are provided from the closed loops to enable operation of the main output channel in a manner that produces driver pulses with the programmed high and low voltage levels.

The field of the invention generally relates to test equipment pin drivers that produce driver pulses to test a device under test, and more particularly relates to an offset compensation circuit that limits output offset voltages in such pin drivers.
As is well known, the role of a pin driver in typical automatic test equipment (ATE) system is to send driver pulses having the correct voltages and timing to a device under test (DUT). One of the important parameters of such driver pulses is the offset voltage which is here defined as the difference between a high or low pulse voltage level VOH or VOL and the corresponding programmed or intended voltage level. In particular, the lower level VOL offset is the difference between the actual pulse voltage VOL in the lower or baseline level and the programmed lower voltage VL which is the intended magnitude origin line. Similarly, the upper level VOH offset is the difference between the actual pulse voltage VOH in the upper level and the programmed upper voltage VH. Offset voltages define driver pulse DC level errors and result in the pin of the device under test being either under or over driven. In most ATE systems, offset voltages higher than 30 millivolts requires automatic calibration which takes up valuable test time. Therefore, it is an important objective in ATE design to have extremely small offset voltages that are well within acceptable tolerances. That is, it is important to have accurate correspondence between the high and low voltage levels of the driver pulses and their corresponding programmed voltage levels VH and VL.
A prototype pin driver was built to include a pulse forming section, a buffer, and an amplifier connected in series. The pulse forming section received a data input and, in response thereto, provided output pulses timed in accordance with the data input. That is, the delay, width, and period of the output pulses were determined by the timing or transitions of the data input. The amplifier stage of the pin driver required a significant amount of input bias current. Therefore, in order to keep the amplifier output driver pulse parameters independent of the load, a buffer was connected between the pulse forming section and the amplifier. Without the buffer, the slew rate of the pulse forming section pulses would have been undesirably dependent upon the loading on the output of the amplifier. The slew rate is here defined as 60%(VOH-VOL)/T.sub.R where T.sub.R is the rise time between 20% and 80% values of (VOH-VOL).
In the above described prototype pin driver, clamp diodes were connected to a node at the input of the buffer to set the high and low voltage levels of the pulses in that stage. In particular, each diode was connected through an emitter to base junction of a respective emitter follower transistor to respective programmed high and low reference voltages VH and VL. The polarities of the clamping diodes were arranged with the intent that one would be forward biased and thereby clamp when the node rose to VH, and the other would be forward biased and thereby clamp when the node dropped to VL. The voltage drops across the respective clamping diodes were to be compensated by the voltage drops across the emitter to base junctions of the respective transistors. The above described prototype was tested, and it was determined that improvement in offset voltage was desirable.

Method and apparatus for limiting pin driver offset voltages


In the electronic equipment of the present application, a center axis of a cylindrical portion 11a of a shaft 11 is eccentric with respect to a rotation center axis of the shaft 11, whereby even when a cable 21 comes closest to the shaft 11 in the turning of a first housing 1 or second housing 2, a sufficient space can be secured between the shaft 11 and the cable 21. Thus, in a turning range of the first housing 1 or second housing 2, it is highly unlikely that the shaft 11 and the cable 21 come into contact with each other, which avoids an increase in a tension of the cable 21 and wear on an insulation cover of the cable 21. By avoiding the increase in the tension of the cable 21, breakage of the electric wires in the cable 21 can be avoided.

1. Field
The present application relates to electronic equipment with a hinge mechanism.
2. Description of Related Art
Conventionally, electronic equipment with a hinge mechanism includes a notebook computer, a foldable mobile telephone, a portable game player, and the like. In such electronic equipment, each of two housings coupled rotatably by the hinge mechanism contains electric components such as an electric circuit board. For example, as for the notebook computer, a first housing contains a motherboard, etc., and a second housing contains a liquid crystal display, etc. The electric components in the first housing and the second housing often are connected electrically by a cable. At this time, the cable often is routed near the hinge mechanism.
However, when the cable is routed near the hinge mechanism, the cable may be disconnected due to the turning movement of the first housing and the second housing.
JP 2003-049823 A discloses a configuration in which, in a rotary hinge mechanism supporting a main body part and rotation part of the electronic equipment, a through hole is provided at a position eccentric from a rotation center axis for improving the degree of freedom in design of the electric wire routing.
JP 2003-018263 A discloses a configuration in which, in a mobile telephone having a first and second housings and a hinge portion, a means for regulating a shift range of a cable is provided for avoiding disconnection of the cable.
JP 06-310874 A discloses a configuration in which, in foldable electronic equipment having two housings and a hinge portion, a blind sheet is provided for preventing disconnection of a wiring pattern.
JP 05-046561 A discloses a configuration in which, in electronic equipment having a main body, cover and hinge, improvements are made for preventing disconnection, etc.
JP 06-152491 A discloses a configuration in which, in a foldable mobile telephone, improvements are made for preventing disconnection of the cable.
In the conventional art, the tension of the cable increases when the second housing is closed with respect to the first housing, which sometimes results in the cable disconnection.
For suppressing the increase in the tension of the cable, there is a method in which the cable is made longer. However, when the cable is made long, it loosens greatly inside the housing when the second housing is in an open state with respect to the first housing. Accordingly, a space for arranging the loosened cable is required in the housing or near the hinge mechanism, which inhibits the downsizing of the electronic equipment. Especially, in the compact electronic equipment such as a mobile telephone terminal, since a space for the cable route is narrow, it is difficult to allocate a space for arranging the loosened cable.

Electronic equipment with hinge mechanism


A camera is covered with a camera housing. The camera and the camera housing form a shooting window portion of a double structure having a clearance. A blowing tunnel communicated with the clearance of the shooting window portion is arranged on each of both sides of the shooting window portion. A blower sends a wind to the shooting window portion through the blowing tunnel. Further, a heater for heating the air sent to the shooting window portion is arranged in the blowing tunnel. Thus, dew condensation preventing ability can be improved by such a construction.

1. Field of the Invention
The present invention relates to a camera device covering a camera with a housing, and particularly relates to a camera device able to prevent dew condensation.
2. Background
In the conventional camera device such as a monitor camera for the outdoors, etc., the dew condensation is generated by the difference between the temperature of an external environment and a camera interior temperature. The temperature of the camera interior is influenced by generated heat of an electronic circuit of the camera, etc. It is required that such dew condensation is prevented. The field of view can be preferably held by the prevention of the dew condensation.
In the conventional camera device, a blower and a heater are arranged within the housing, and a warm wind is sent to a shooting window portion to prevent the dew condensation. In another conventional technique, it is proposed that an optical glass and a filter of a double structure are arranged in the shooting window portion, and nitrogen gas is sealed between a clearance between the optical glass and the filter, or the clearance between both the optical glass and the filter is set to a vacuum. Such a technique is disclosed in JP-A-10-285454 (third page and FIG. 4).
However, in the conventional camera device, dew condensation preventing ability is low since only the blower and the heater are used. It is necessary to arrange comparatively large-sized blower and heater so as to obtain a sufficient dew condensation preventing effect. Further, when the nitrogen gas is sealed in the clearance between the optical glass and the filter or the clearance is set to a vacuum, it is not easy to hold the clearance portion in a seal state. Therefore, it is not easy to obtain high dew condensation preventing ability.


The invention relates to a syringe cap (1) for a medical syringe (28), having two cap parts (2, 3) displaceable toward each other, wherein a motion of the cap parts (2, 3) toward each other takes place when the syringe cap (1) is first removed from the syringe (28). In order to disclose a syringe cap for a medical syringe, wherein a first use can be advantageously determined and handling is simple, according to the invention an indicator element is displaced into a display setting and the display element (6) can be removed from the syringe (28) together with the cap parts (2, 3) of the syringe cap (1).

1. Field of the Invention
The invention relates to a syringe cap for a medical syringe, comprising two cap parts that are moveable toward one another, a movement of the cap parts toward one another taking place when the syringe cap is removed for the first time from the syringe, and by virtue of this, a displacement of an indicator element takes place.
2. The Prior Art
Such syringe caps that are also designated as syringe end caps or tip caps are known in varied respects. For example, reference is to be made to an item of prior art according to U.S. Pat. No. 6,196,998 B1. In the case of the syringe cap known therefrom, two cap parts are provided—a first cap part that forms a distal end region of the syringe cap, and a second cap part that forms a proximal end region of the syringe cap. "Proximal" means here that after fitting the syringe cap onto the syringe, it is disposed facing the cylindrical part of the syringe body, which cylindrical part has a plunger part. These cap parts are connected to one another via predetermined breaking webs. In the course of a first unscrewing of the syringe cap from the syringe, the cap part forming the distal end region is separated from the further cap part by tearing it off. By this, a first use is detectable. The cap part associated with the distal end can be removed from the syringe while the other cap part remains on the syringe.


Methods and related apparatuses of a downhole micro nuclear magnetic resonance (NMR) device having a resonant tuning (LC) circuit for use in a formation for collecting NMR signals from a fluid in the formation while under downhole pressures and temperatures. The downhole micro NMR device includes: a micro tube for the flowing fluid to flow therethrough; at least one magnet disposed about the micro tube; and at least one micro RF coil structured and arranged approximate to the micro tube and tuned to a Larmor frequency corresponding to a applied magnetic field from the at least one magnet.

Nuclear Magnetic Resonance (NMR) measurements of oil properties have been used to aide in reservoir fluid characterization since the early 1950s. Today, the detailed knowledge of fluid composition is a key ingredient for successful management of oilfield reservoirs. The oil composition determines the Pressure-Volume-Temperature (PVT) behavior. Viscosity measurements in addition to the T1, T2, diffusion, chain length, chemical structure, emulsion, waxing, and phase transition are all important fluid properties. Viscosity can be used as a fingerprint for other reservoir properties, such as compartmentalization. Compartmentalization is the situation in which some reservoirs have multiple levels of 'pay zones' and these may or may not be hydraulically connected. This has implications for the production and completions design and execution. During production there can be asphaltene drop-out or waxing problems that can cause loss of production. It is highly desirable to measure fluid properties under downhole conditions since many properties depend critically on temperature and pressure. It is also well understood that samples can undergo irreversible changes as they are extracted from the formation and transferred to the laboratory.
There are various downhole tools such as the MDT and the CHDT (trademarks of Schlumberger) tools that can be useful in obtaining and analyzing fluid samples. The downhole tools such as the MDT tool (see, e.g., U.S. Pat. No. 3,859,851 to Urbanosky, and U.S. Pat. No. 4,860,581 to Zimmerman et al., which are hereby incorporated by reference herein in their entireties) typically include a fluid entry port or tubular probe cooperatively arranged within wall-engaging packers for isolating the port or probe from the borehole fluids. It is noted they also include sample chambers which can be coupled to the fluid entry by a flow line having control valves arranged therein.
Regarding NMR measurements, the fluid sample is located in a static magnetic field and exposed to resonant frequencies (RF) pulses. The generated RF signal, produced by the irradiating RF pulses to the fluid sample, is then recorded. Depending on the exact configuration of the static field and the details of the RF pulses that are applied to the sample, many different measurements can be implemented. With uniform static fields, NMR spectra can be recorded that give information on the chemical composition of the fluids. If the static field is made non-uniform, either by applying a static field that is spatially non-uniform or by applying pulsed gradient fields, NMR imaging, diffusion and flow measurements become possible. In all cases, relaxation measurements can also be performed.

Microcoil NMR for downhole microfluidics platform


A position control, latch, and locking apparatus for use with a retractable cover used to securely enclose a pickup truck utility bed. The latch and lock mechanism is placed in a modified lead slat of the cover for latching to the cover guide tracks and to the tailgate. A key lockable actuating handle is placed on the slat concealing linkage arms pivotally connected to the handle further attached to a first and second diametrically opposed push rod for simultaneous operation of a four point spring biased latching mechanism. A flexible strap is connected to the cover to manually move the cover. The latching mechanism secures the cover to the sidewalls of the pickup truck as well as locking the tailgate in an upright position. A tailgate lip cover and attachment device is also disclosed for securely fastening the modified slat to the tailgate and provide a planar surface allowing for sealing and concealment of the latching mechanism.

1. Field of the Invention
This invention relates generally to a retractable truck utility bed cover and, in particular, to an apparatus for positioning, latching, and locking a retractable rolling security cover used to securely enclose (partially or fully) a truck utility bed.
2. Description of the Prior Art
Truck bed covers are known to protect a pickup truck bed enclosure and especially items placed therein. By securing a cover to the truck bed side rails, an enclosure is formed capable of protecting items against theft and exposure to rain, snow, and wind. The cover may sometimes provide an aerodynamic profile and, depending upon the overall shape and profile, enhance gasoline mileage.
Rollable or roll up covers have improved the pickup truck cover by providing a slidable, retractable, impervious cover positionable over the entire length of the bed. A rolling truck bed cover may be comprised of a plurality of elongated plastic or aluminum slats hinged together and disposed between a pair of parallel guide tracks, each securely clamped to opposite sides of the utility bed. One end of the retractable cover connected to a reel in a reel housing about which the cover can be rolled. The cover free end should be secured at or near the tailgate to prevent the unauthorized entrance and access into the utility truck bed enclosure formed by the cover.
The rolling truck bed cover for which this invention is used is comprised of a plurality of elongated rectangular slats hinged movably in a side by side array having arcuate male and female hinges along the longitudinal edges which interlock adjacent slats together providing an impervious surface in a closed position. Each slat is constructed of extruded aluminum and includes an elongated seal member in each arcuate slat hinge to protect against water entry. A slat end block constructed of molded plastic is placed at each end of the slat for contact with the guide tracks on both sides. Upper and lower plastic guide runners mounted in the guide tracks frictionally engage the lower surface of each slat and limit upward movement providing non metal contact to reduce or eliminate noise.
Lockable retractable truck bed covers are shown in the prior art. U.S. Pat. No. 4,807,921, issued to Champie, discloses a sliding cover for a truck bed which includes the use of a recessed paddle-handle lock to secure the cover to the tailgate. Champie discloses the paddle-handle lock which eliminates the need for the "T" handle rod lock generally used to latch components onto the sides of a pickup truck bed. Champie does not disclose or teach a device to lock the cover in an open, partially open, or otherwise to the sidewalls as well as the tailgate.
U.S. Pat. No. 4,795,206, issued to Adams, discloses a pickup truck cover system which includes a tailgate locking mechanism to lock the cover in the closed position. The locking mechanism employs a spring member to bias the engagement latch in an open position and a key member to secure the engagement latch and cover forming an impervious enclosure. Adams illustrates a conventional latch using a hook and cam portion which is pivotally connected to the rail for use in locking the cover to the side rail. Adams illustrates a hook portion with a latch member to engage a plate member mounted on the tailgate. Under such a teaching, the Adams locking mechanism requires multiple locking locations to secure the cover. The key system of the Adams device is complicated and dependent upon a latching mechanism that could be overcome with force.
U.S. Pat. No. 4,889,381, issued to Tamblyn et al. Dec. 26, 1989, shows a retractable truck bed cover that includes a conventional key actuated arm that fits into a slot on the tailgate, apparently a single locking point.
U.S. Pat. No. 4,611,848, issued to Romano for a sliding cover assembly for open body trucks Sep. 16, 1986, shows a latch handle at the rear of the truck without discussion.
One of the drawbacks of all these devices is the fact that the manual actuation, which requires the operator to physically walk from one end of the bed to the other in order to secure closure, appears deficient. Actuation of the entire cover is awkward, time consuming, and cumbersome. Also, none of the bed covers discussed provide for intermediary positions where the cover can be secured so that the cover can be partially open. Finally, the cover locking mechanisms in most of these devices appear to be inadequate to securely prevent someone from easily overcoming the locking mechanism for unauthorized disclosure, reducing the security advantage of the device.
The instant invention addresses the aforementioned problems by providing a four point latch and lock system made operational from a single key operated location. The invention provides for locking the cover to each side rail guide track and two separate locations on the tailgate for optimum securement. The cover can also be positioned and secured to a number of intermediary positions between full open and complete closure. Most importantly, the closure can be operated from a single location by one person at the tailgate for full open, partial open, complete closure, and lock, using an actuating strap and a lock set handle.

Apparatus for positioning, latching and locking a retractable truck bed cover