Shigeyuki Matsumoto

A 310 K pixel bipolar imager (BASIS)

The BASIS (base-stored image sensor) bipolar imaging device, which consists of a bipolar phototransistor in a capacitor-loaded emitter-follower circuit, is discussed. The device is used in an imager with 310 K pixels (640 H*490 V) in a 2/3-in optical format. The imager exhibits excellent performance characteristics, such as a high aperture ratio of 60%, an image lag less than 0.1%, and good linearity with a dynamic range of 76 dB. The read out and reset operation, antiblooming capability, and total system circuit and FPN cancellation are discussed. >

A 3.9-/spl mu/m pixel pitch VGA format 10-b digital output CMOS image sensor with 1.5 transistor/pixel

A 3.9-/spl mu/m pixel pitch VGA format 10-b digital output CMOS image sensor with 1.5 transistor/pixel has been developed for mobile applications. The newly developed CMOS pixel architecture realizes the minimum number of the transistors in one pixel. Small pixel size and sufficient fill factor are achieved by using the shared pixel architecture and floating diffusion driving. High conversion gain, low random noise, and low dark current are achieved by buried photodiode with complete charge transfer capability and correlated double sampling (CDS) circuit. The image sensor is fabricated in a thin planarized 0.35-/spl mu/m single poly-Si double-metal customized CMOS process in order to provide good image performance. The image sensor achieves low noise floor of 330 /spl mu/V and low dark current of 50 pA/cm/sup 2/ at 45/spl deg/C. This image sensor also realized various functions by on-chip digital and analog circuits.

A low-noise Bi-CMOS linear image sensor with auto-focusing function

A bipolar imaging device consisting of a capacitor-loaded emitter follower circuit for a phototransistor has been implemented in a linear image sensor with two lines of 48-bit array for an autofocus camera system. The sensor, which has self-noise reduction and charge amplification capabilities, has demonstrated excellent performance, such as responsivity of 24 V/x-s, a wide dynamic range of 85.3 dB at a storage time of 10 ms and ambient temperature of 25 degrees C, a high S/N ratio of 27.6 dB at a faceplate light intensity of 1*10/sup -3/ lx, a storage time of 200 ms, an ambient temperature of 25 degrees C, and applicability in a range of light intensity from 1*10/sup -3/ to 1*10/sup 4/ lx. >

A 310 k pixel bipolar imager (BASIS)

A bipolar imager with an amplification function in each pixel has been developed using BiCMOS technology. The imager, which stores photocarriers in the base regions of the bipolar transistor pixels, is called the base-stored image sensor (BASIS). BASIS-type devices have been faced with three problems: (1) a reset transistor is needed in each pixel to initialize base voltage; (2) nonuniformity of offset voltage appears as fixed pattern noise; and (3) blooming is induced by intense light. Effective methods of dealing with these problems have been found. A BASIS imager with 310 k pixels in a 2/3-in optical format is described. The device specifications and characteristics of the imager are summarized.<<ETX>>

A New Bipolar Imaging Device (BASIS)

A bipolar imaging device consisting of a capacitor loaded emitter follower circuit for a photo-transistor has been implemented into linear image sensors, which has capabilities of charge amplification and self-noise-reduction. The linear sensors are demonstrated experimentally to exhibit excellent performance such as a linearity in a wide dynamic range and a high sensitivity.