Abstract: An improved reticle (20) and method of using it to expose layers of wafers for large integrated circuits (10). The integrated circuit (10) is designed so that nonrepeating patterns are laid out in perimeter areas, distinct from the center area containing contiguous repeating patterns. The reticle (20) is patterned with multiple masks (21-23), with different masks representing the repeating and nonrepeating patterns. The mask (22) representing the repeating pattern may then be stepped and illuminated separately from any mask (21, 23) representing a nonrepeating pattern.

Abstract: A brightness sensing circuit for providing a binary electrical signal for indicating whether incident light exceeds a certain brightness. The circuit's light detector is a photodiode, whose output is amplified by a first current mirror. The circuit has a reference current source, whose output is amplified by a second current mirror. Both currents are delivered to a common node, whose voltage level transitions from low to high when the amplified input current exceeds the amplified reference current. This node is connected to the gate input of a CMOS inverter, which provides a binary output.

Abstract: A method for controlling a digital micromirror device 40 resulting in decreased mechanical stress, longer device lifetimes, decreased incidence of spontaneous bit reset, and increased pulse-width modulation accuracy. To reduce the device stress, the bias voltage 142 applied to the mirror 50 may be reduced after the mirror 50 has been latched. To prevent premature mirror changes, the address electrode bias voltage 140 may be reduced after the mirror is driven to the desired position. To ensure that the mirror 50 returns to the neutral position during reset, the mirror bias voltage 142 may be raised from ground potential to approximately halfway between the two addressing voltages during the reset period 152. To reduce the effects of hinge memory and to ensure that the mirror 50 rotates toward the proper address electrode, the mirror bias voltage 142 may be gradually increased to allow the mirror 50 time to rotate towards the proper address electrode.

Abstract: A circuit primarily for use in conjunction with focal plane arrays which rejects input reset noise without adding power and complexity to the circuit. The circuit includes a preamplifier having input and output terminals, a first capacitor coupled between the input terminal and a source of reference potential, a second capacitor coupled between the output terminal and the source of reference potential, a switch coupled between the output terminal and the second capacitor coupling the output terminal to the second capacitor in response to a first predetermined signal, a third capacitor coupled between the junction of the switch and the second capacitor and a circuit output terminal and a plurality of fourth capacitors, each of the fourth capacitors coupled to a photodetector and having a switch responsive to a second predetermined signal controlling coupling of the fourth capacitor in parallel with the first capacitor.

Abstract: An infrared imager, wherein a transparent gate 14 is separated from a very narrow bandgap semiconductor 106 (such as HgCdTe) by a thin dielectric 15, 62. The gate 14 is biased to create a depletion well in the semiconductor 106, and photo-generated carriers are collected in the well. The gate voltage is sensed to measure the accumulated charge. Preferably the accumulated charge is not sensed directly from the gate, but the gate output is repeatedly averaged with another capacitor, so that the output of the imager is sensed as in average over a number of read cycles, which provides a greatly improved signal-to-noise ratio. Preferably an array of the MIS detection devices is formed in a thin layer of HgCdTe 106, which is bonded to a silicon substrate 107 containing a corresponding array of the averaging capacitors with addressing and output connections, and via holes 16 through the HgCdTe are used to connect each detection device to its corresponding averaging capacitor.

Abstract: An infrared imager, wherein an array of detection devices is formed in a thin layer of HgCdTe, which is bonded to a silicon substrate containing a corresponding array of averaging capacitors with addressing and output connections, and via holes through (or bump bonding pads on) the HgCdTe are used to connect each detection device to its corresponding averaging capacitor. The signal from each detection device is repeatedly averaged into its averaging capacitor, so that the output of each pixel site is sensed as an average over a number of read cycles which provides a greatly improved signal-to-noise ratio.

Abstract: An infrared imager, wherein a transparent gate is separated from a very narrow bandgap semiconductor (such as HgCdTe) by a thin dielectric. The gate is biased to create a depletion well in a semiconductor, and photo-generated carriers are collected in the well. The gate voltage is sensed to measure the accumulated charge. Preferably the accumulated charge is not sensed directly from the gate, but the gate output is repeatedly averaged with another capacitor, so that the output of the imager is sensed as an average over a number of read cycles, which provides a greatly improved signal-to-noise ratio. Preferably an array of the MIS detection devices is formed in a thin layer of HgCdTe, which is bonded to a silicon substrate containing a corresponding array of the averaging capacitors with addressing and output connections, and via holes through the HgCdTe are used to connect each detection device to its corresponding averaging capacitor.

Abstract: A focal plane array infrared device includes an optical system for focusing incoming infrared energy, a scanner for scanning the focused infrared energy onto a focal plane detector array for converting the infrared energy into electrical signals representative of the intensity of the infrared energy signals, a multiplexer for multiplexing the focal plane detector array electrical output to a dynamic preamplifier for amplification to a working level and a data processing means including a dynamic amplifier connected to the preamplifier for removing correlated noise from the information signal prior to signal processing, the dynamic amplifier including a plurality of switched capacitors and a transistor controlled by a controller whereby the incoming signals are stored in selected capacitors, amplified and combined to produce a difference signal at the output substantially equal to the focal plane detector array output.

Abstract: A thermal energy imaging system includes an optical system for focusing thermal energy emanating from a scene on an array of bulk semiconductor photodetectors. The detector array outputs electrical signals representative of the impinging thermal energy, a video electronic circuit and a pseudo ac coupling circuit interconnecting the detector array and video electronic circuit for reducing the required dynamic range of the video electronic circuit. The pseudo ac coupling circuit includes first and second electrical paths to an sychronous clamp. The first path includes a switch to the synchronous clamp; the second clamp includes first and second integrator circuits and a switch; the switch is connected to the synchronous clamp. The synchronous clamp includes an amplifier, capacitor and grounded switch.

Abstract: A heterodyne laser ranging system is disclosed which provides a waveguide housing which includes a first and second gas laser. The first laser is a low pressure laser while the second laser is a high pressure laser. These two lasers formed in the waveguide housing have their longitudinal axis in optical alignment. In the preferred embodiment, the second high pressure gas laser is a transversely excited atmospheric (TEA) laser. The first low pressure gas laser produces two outputs, one of the outputs is a low level local oscillator signal while the second output is transmitted as an input to the high pressure laser. The second high pressure laser builds up from the injected signal from the low pressure laser which results in a high pressure laser pulse output that has the frequency stability of the low pressure laser while maintaining the high peak power output available from a transversely pumped waveguide laser.