A new photodiode structure has been developed to reduce smear and to increase photo-sensitivity in CCD image sensors. The new structure features a wide, low-concentration N^- layer formed below the conventional photodiode N layer. The new photodiode was designed by using a new parameter deduced from simulated potential-profiles to help optimize the N^- layer conditions. The new structure was applied to a 2/3-inch 2M pixel interline-transfer CCD (IT-CCD) image sensor, and it has achieved a low smear (-85dB) as well as high sensitivity (35 nA/lx).
A single layer electrode two-phase CCD is studied for a purpose of obtaining low driving voltage CCD image sensor. The CCD has both a storage region under a thick gate oxide and a battier region under a thin gate oxide for each transfer electrode. In order to attain high charge transfer efficiency for an extremely low driving voltage, a new alignment-deviation-free structure and a potential pocket suppression structure are introduced. A 1/3 inch format 270k pixel interline-transfer image sensor with the horizontal CCD driving voltage of 1.8 V is developed by employing the single layer electrode structure.
A 1/3-inch 630k-pixel IT-CCD with multi-function of a vibration stabilization, an electronic zoom and a 16 : 9 wide aspect imaging has been developed. 3.3V-driving of a horizontal CCD and a reset gate has been achieved. New preadjust bias circuits using non-volatile analog memory enable the substrate and reset gate bias to be free from external adjustment.
We have developed a multi-use CCD that is adaptive to various appplications. An experimentally fabricated 2/3-inch 800k-pixel CCD outputs video formats with different aspect ratio(16 : 9/4 : 3). The device shows a sufficient performance for broadcasting use regardless of the aspect ratio- sensitivity of 140mV/lx, dynamic range of 80dB, smear level of -120dB and S/N ratio of 60 dB.
A 5000-element CCD linear image sensor with adjacent RGB photodiode rows has been successfully developed. Reading out signal charge of the middle row is accomplished by a charge transfer through a vacant neighboring photodiode row. Low non-uniformity and good color balance are obtained at data rates up to 16MHz where the transfer efficiency is 96%.
Sensitivity to light, i.e. quantum efficiency, of photodiode and CCD which are used for photodetector of camera and for image sensor of video camera, respectively, shows different dependence on wavelength from human luminosity. Therefore, adjustment of luminous efficiency with photometric filters or luminous efficiency filters is required to actual use for camera and video camera. Hitherto, the optical filters made of specific phosphate glass incorporated with metal ions or sputtered glass have been used as the luminous efficiency filters. However, as to the conventional filters made of glass, several problems such as ghost appearance attributed to reflex, wrong adjustment to luminosity, high hygroscopicity and costly complicated production process have been pointed out. Kureha Chemical Industry Co., Ltd. realized the luminous efficiency filter made of synthetic resin named UCF which has solved the problems mentioned above, and began marketing in 1993 as the first plastic product in the world. In this presentation, the characteristics and the production process of the UCF are discussed.
The 1994 start of test HDTV program breadcasting in Japan made the development of HDTV systems a priority for many companies; marking the real start of HDTV for practical commercial use. The market has also found practical professional applications for the picture quality and cost performance of the W-VHS Hivision VTR; even though W-VHS horizontal resolution is limited relative to full band-with Hivision. The high perceived quality relative to NTSC results rather from greater than 800 lines vertical resolution, the 16-9 aspect ratio, and component recording. Therefore to balance high picture quality and acceptable cost for practical professional use, the following camera targets were set : A) 700 to 800 linea for both horizontal and vertical resolution. B) Uniform picture quality for both centre and corner image areas. High quality 16 : 9 lenses have already been developed that meet the need for precision in optical evaporation and correction for lateral chromatic aberrations. High cost exclusively HDTV lenses are not needed. The image collection device is a 2/3 inch. IT, 1 Million pixel, elliptical lens-on-chip CCD made by the NEC Sensor Division. This paper also discusses cost performance of the optical low pass filter, digital aspect error correction, signal processing features, digital signal processing including RGB detail enhancement, and camera construction; including CCD heat dissipation measures.
A new camera DSF and control system for it have been developed. Y and C process, AF and AE and AWB detecter, timing generater, and electronic zoom process are integreted on the DSP. The control system performs realized AE, AWB, AF by one chip.
We have newly developed a 3-CCD camera system called "The New 3-CCD Camera System" to improve the performance under various conditions such as back-lit. Electronic image Stabilization mode, high rate zoom, poor illuminated, etc. As a key technology for realization, it employs some new signal processing such as Neuro-Gamma. Vertical Stagger Processing, and New Noise Reduction to improve the performance under above condition. The 0.5um process and chip integration make digital LSis high density integrated and low powered.
Newly developed 4CCD Hi-Vision portable color camera utilized consumer type CCDs, which enables to have features of compactness, light-weight, low cost and low power consumption. As a result, the horizontal and vertical resolutions are more than 650 TV lines thanks to new 4CCD dual green system and special pixel offset imaging betweem G1 and G2 CCDs and between G1/G2 and R/B CCDs. Hi-Vision and NTSC modes are switchable by applying the digital process circuit.