[in Japanese]

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[in Japanese]

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[in Japanese]

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A 1/3-inch 360 kpixel IT-CCD image sensor has been developed to satisfy recent demand for small CCD image-sensors with higher resolution and higher sensitivity. The photo-diode aperture and the microlens structure were optimized using microlens simulation technology. As a result, a minimum object illumination of 3 lux and a low smear level of 0.002% have been achieved.

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An HDTV 2/3-inch CCD hand-held camera has been developed to meet the demand for a small, light, maintenance-free HDTV camera. This paper describes the design concept of 2/3-inch CCDs and pickup systems, taking into account present LSI technology and HDTV camera performance requirements.
One limitation is that downsizing CCDs from the 1-inch to the 2/3-inch optical format inevitably reduces the area of each pixel, resulting in insufficient dynamic range and sensitivity. To maximize the 2/3-inch CCD overall characteristics, we used 1.3 million instead of 2 million pixels.
To attain sufficient resolution with a reduced number of CCD pixels, we compensate for resolution deterioration by using the dual-green pickup method. This method provides sufficient resolution for an HDTV camera with reduced aliasing.
This camera has successfully achieved a horizontal resolution of 1100 TVL and exhibits well-balanced performance.

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A one-inch format 1.5 M pixel Interline Transfer (IT) CCD image sensor has been developed for an HDTV camera system. We focused on two areas to achieve a low smear ratio while maintaining high sensitivity. One is the VCCD device structure. By using the device simulator, we have developed a new impurity profile for the buried P⁺-layer under the VCCD. The other focus area is the optical structure. Considering the incident angle, we simulated the optical path. This simulation helped us determine the size of an optical shield and an onchip microlens made of a deep-UV resist. We have achieved a sensivity of 80 nA/lx, a maximum charge handling capacity of 1.2×10⁵ electrons, and a smear ratio less than-110 dB. A high-fidelity picture with a horizontal resolution of 820 TV lines has been obtained.

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This paper presents the experimental results of a high resolution CMD (Charge Modulation Device) image sensor. This sensor features ultra-low power dissipation and a low smear level.
We designed, fabricated and studied a 2M pixel CMD image sensor. A pixel size of 7.3 μm (H) ×7.6μm (V) was used to obtain a 1-in optical format HDTV image sensor. We achieved a die size of 16.6 mm (H) ×10.7mm (V), even though the clock drivers for the scanners were fabricated in the sensor chip.
The smear level was-123 dB and the power dissipation was 206 mW. The saturation signal current per pixel was 28 μA at an exposure of 76 lx (T_c=5100 K, 1/60s integration). The signal had good linearity of photoconversion characteristics. Furthermore, the image lag was lower than the detectable limit (0.1% of the saturation signal).

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Recently, CCDs have shown remarkable improvements, mainly due to the popularity of home video cameras. With the spreading applications of these devices, CCD cameras have had to become smaller. The authors designed a structure to make CCD cameras as small as possible. The design uses a COG (chip on glass) -CCD module to attain the highest assembly density and the smallest CCD. The authors investigated the reliability of a new assembly technology to produce the COG-CCD module. This new technology was used to manufactured a sub-miniature CCD color camera. The diameter of this camera was 8 mm, its length approximately 30 mm, and its weight approximately 2 g. This new technology will improve the miniaturization of CCD cameras and spread their application to many fields.

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We studied three types of logarithmic photo-receptor elements, consisting of a diode connected MOSFET in series with a photodiode. The performance limits were established and the effects of the device configuration and the operation mode on the logarithmic nature of the response were experimentally verified. It was found that the photoreceptor element biased to a punchthrough mode had a wider dynamic range and output voltage swing than that obtained under subthreshold current mode operation. We measured the logarithmic response of the photoreceptor with a channel length of 3.3 μm and a dark current density of approximately 100 nA/cm². Measurement was conducted over a range of 10⁴ of incident light intensity with a sensitivity of 650 mV/ decade.

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[in Japanese]

View full abstract

[in Japanese]

View full abstract