Nozomu Harada

A high-sensitivity MOS photo-transistor for area image sensor

A new MOS phototransistor, called a double-gate floating surface phototransistor, has been fabricated and evaluated. In the phototransistor cell, the gate area has been divided into two parts, the accumulation section and the detection section, in order to realize a low input capacitance for a high optical gain. The device achieved a noise equivalent exposure of 2*10/sup -4/ lx at 16-ms integration time and a dynamic range of 75 dB with a new line potential modulation operation. >

A new high sensitivity photo-transistor for area image sensors

A novel MOS phototransistor with a high optical gain, called a double-gate floating-surface phototransistor, has been proposed and fabricated. The phototransistor realizes a 0.8-electron RMS noise equivalent signal over a 3.58-MHz-wide band. It achieves a dynamic range of 75 dB with an amplification characteristic suitable for TV-camera application. It is concluded that an ultra-high-sensitivity image sensor can be realized with this device.<<ETX>>

A photoelectric conversion-characteristic control method for interline transfer CCD imager

There are generally two approaches to dynamic range expansion for a solid-state imager. One is output-noise decrease. Another approach is a maximum signal-charge increase. An interline transfer CCD imager has an advantage in regard to low output noise, while its maximum amount of signal charges is lower than that for the other kinds of imagers, MOS, CPD, etc. Using a new operation mode, dynamic-range expansion for the interline transfer CCD imager has been achieved. There is a knee point in the photoelectric conversion characteristic.

A 1.9 M-pixel poly-Si TFT-LCD for HD and computer-data projectors

A 3.3-inch 1.9 M-pixel poly-Si TFT-LCD for high-definition and computer-data projectors has been developed. This LCD is able to display both full-band HD signals and computer data. This unique applicability is realized by adapting novel CMOS decoder circuits integrated on the substrate. By arranging these decoder circuits on both sides of the panel, effective redundancy is also realized. An oxidation thinning process and a low-resistance tungsten-polycide gate electrode are used in fabricating the poly-Si TFTs, and n-channel MOS-TFT mobility of 160 cm/sup 2//Vs was realized. A horizontal resolution of 1000 TV lines mid a contrast ratio of 200:1 is achieved.

3.3-inch, 1.9 MPixel integrated driver poly-Si TFT-LCD for HDTV projector

LCDs with 1.5 M-pixels for HDTV projectors display multiple sub-Nyquist sampling encoding (MUSE) signals with 20 MHz bandwidth. 1000-TV-line-resolution LCDs with 30 MHz HDTV bandwidth are now required. LCD projectors are also required to display computer data such as VGA and SVGA. In the case of SVGA, conventional LCDs using shift-register drivers cannot be used because the shift register must operate at much higher frequency in the no-picture region.<<ETX>>

Analysis of Charge Transfer Loss in Dual Read-Out Registers Used for HDTV CCD Image Sensor

Dual read-out register structure is indispensable for high definition television (IIDTV) CCD inage sensors to realize high signal read-out frequency (74.25MH2). llowever, this structure would suffer from a charge transfer loss between two read-out registers, unless precise care was taken in designing the registers. This paper describes the charge transfer loss nechanisn and proposes a new dual register structure, which can elininate this problen. As a result, the charge transfer loss is conpletely suppressed.

A new, laminar flow photo-CVD method for preparing hydrogenated amorphous silicon films

A new, laminar flow type photochemical vapor deposition method has been applied to prepare a-Si:H films. The main feature of this method is introduction of Ar gas as a flow down gas through the lower part of the quartz window into the reaction chamber to keep the window highly transparent. The high deposition rate (150 A/min) of the a-Si:H film has been stably maintained by optimizing the flow rate for each gas into the chamber. Utilizing this new method, we have been able to realize high quality films with low impurity content, high resistivity (>10 11 Ω cm), low dangling bond density (5×10 15 cm -3 ), etc

Ultra high sensitivity on-chip amplifier for VLSI CCD image sensor

A novel high-sensitivity on-chip amplifier for CCD (charge coupled device) image sensors is evaluated within a very small signal range of under 20 electrons, which is the photon counting region for highly sensitive imaging devices. Because the output noise of 0.084 mV RMS is smaller than the output voltage/electron of 0.22 mV/electron measured in the larger-signal region, the discrete voltage levels corresponding to numbers of signal electrons were directly observed in an oscilloscope in the small signal region. By this observation, it was confirmed that high responsivity is maintained in the very-small-signal region. Therefore, it is possible to realize a photon-counting solid-state image sensor and a highly sensitive megapixel-level HDTV (high-definition television) imager

A ½-Inch 792(H) × 492(V) Pixel Colour Synchro Vision CCD Image Sensor

Publisher Summary This chapter discusses a ½-inch 792(H) × 492(V) pixel color synchro vision charge-coupled devices (CCDs) image sensor. A black and white synchro vision (SV)-CCD with CCD swing operation realizes a doubling in resolution. CCD swing operation was also applied to a one-chip color CCD with a checkerboard pixel layout. A new high-resolution SV-CCD image sensor using a ½-inch 792(H) × 492(V) pixel CCD chip has been fabricated. This device has achieved simultaneous resolution enhancement for both luminance and color signals. In addition, aliasing and Moire effects have been significantly reduced without using an optical low-pass filter. The pixel unit is composed of a photodiode and a vertical CCD register, which is optically shielded. The area of the photodiode is the aperture for incident light. A full-frame element comprises the signal stored at the first site during one field and that stored at the second, adjacent, site during the next field interval.

A High Resolution CCD Imager Module with Swing Operation

A new, high resolution CCD imager has been developed. An interline transfer CCD chip is swung synchronously at frame frequency in a horizontal direction with the aid of newly-designed piezoelectric bimorph actuators. Though the swing operation using these actuators, 560 TV line horizontal limiting resolution, is twice higher than the conventional operation, it has been realized without increasing CCD pixels on the Si-chip. The newly-designed signal processing circuit, its band being less than 7 MHz, fits the NTSC system and has achieved high-resolution images for the new device.