JPS62291169A - Ccd image sensor - Google Patents

Abstract

PURPOSE:To enhance the sensitivity and the high speed of a CCD image sensor by forming two sets of CCD line sensors ON-hips. CONSTITUTION:Two sets of single channel type CCD line sensors having photoelectric converter rows 1-1, 1-2 in which photoelectric converters are disposed in one row at a predetermined interval, shift registers 2-1, 2-2 for receiving charge from the converters to transfer the charge, and transfer gates 3-1, 3-2 provided between the rows 1-1, 1-2 and the registers 2-1, 2-2 are disposed in a plane symmetrical position in parallel to be integrated on a semiconductor substrate. The symmetrical plane is a surface passing perpendicularly to the sheet in the center of the rows 1-1, 1-2 in the drawing, the two sets of the sensors are disposed symmetrically with respect to the symmetrical surface in a mirror-reflecting relationship. Thus, the reading velocity can be accelerated and the sensitivity can be enhanced.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a CCD image sensor, and particularly to a CCD linear image sensor.

1' Prior Art J Conventionally, as shown in FIG. 3, a CCD linear image sensor has a configuration including a photoelectric conversion element array 1 and shift registers 2a and 2b arranged on both sides of the array.

In FIG. 3, arrows drawn with broken lines indicate the direction of charge transfer.

[Problem that the invention seeks to solve]

The conventional CCD linear image sensor described above has only one photoelectric conversion element array, so if, for example, you want to read a video signal in color without lowering the resolution, you need to prepare multiple identical image sensors and change the optical system. A method is used, such as dividing the passed light using a half mirror or the like and reading it with each sensor. However, in this case, the position of each sensor must be adjusted with high precision, and the amount of light is attenuated as it is divided, so a more powerful light source is required, resulting in increased costs and larger equipment. The disadvantage is that it leads to

Also, since it is read sequentially with one photoelectric conversion element row,
There is a point X where the reading speed is slow or the photosensitivity is low.

An object of the present invention is to provide a CCD image sensor that can generate two video signals.

Another object of the present invention is to provide a C
The purpose of the present invention is to provide a CD image sensor.

[Means for solving problems]

The CCD image sensor of the present invention includes a photoelectric conversion element array in which photoelectric conversion elements are arranged in a line at predetermined intervals, a shift register that receives and transfers charges from the photoelectric conversion elements, and the photoelectric conversion element array and the shift register. Two sets of single channel type CCD line sensors each having a transfer gate provided between the two are arranged parallel to each other in plane symmetrical positions and integrated on a semiconductor substrate.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention;
FIG. 2 is a schematic plan view showing the arrangement of photoelectric conversion elements in one embodiment of the present invention.

This embodiment includes a photoelectric conversion element array 1-1 (or 1-2) in which photoelectric conversion elements are arranged in a line at predetermined intervals, and a shift register 2-1 that receives and transfers charges from the photoelectric conversion elements.
(or 2-2) and a transfer gate 3+ (or 3-2) provided between one row of photoelectric conversion elements 1-O (or 1-2) and the shift register 2-1 (or 2-2). Two sets of single-channel type CCD line sensors are arranged parallel to each other in plane-symmetrical positions and integrated on a semiconductor substrate.

The plane of symmetry is the photoelectric conversion element row 1-! in FIG. .

This is a plane that passes through the middle of 1-2 perpendicularly to the plane of the paper. The two sets of CCD line sensors are arranged symmetrically with respect to this plane of symmetry. In other words, they are mirror images of each other.

The horizontal resolution is proportional to the pitch of the photoelectric conversion elements in the photoelectric conversion element row 1-1 or 1-2, that is, the reciprocal of the column direction pitch a.

Next, how to use this embodiment will be explained.

First of all, the same object (for example, the same column of the read original)
If the reflected light is separated into two systems by an optical system and incident on the photoelectric conversion element arrays 1, 1, and 12, colorization is possible. In this case, although the principle is the same as using two CCD linear image sensors, the entire document reading device can be made smaller.

Second, reflected light from two adjacent objects can be used by making them incident on the photoelectric conversion element arrays 1-1 and 1-2, respectively. In this case, the vertical mechanical scanning interval can be twice that of a CCD line sensor. The vertical resolution in this case is inversely proportional to the pitch of the photoelectric conversion element array in the row direction. For example, when used to read a facsimile document, the required resolution is 8do both horizontally (in the electrical scanning direction by the CCD sensor) and vertically (in the direction in which the document is fed by the mechanical system).
If the pitch a in the column direction is 10 μm when the pitch is t/mm, the pitch b in the row direction may also be 10 μm. horizontal 8do
If t/dragon, vertical 4 dots/gang, then the ratio is vertical/horizontal - 4/8 = 1. /2, so it is sufficient to set b/a = 2. Therefore, if the column direction pitch a is 10 μm, the row direction pitch b
is 20 μm. With this configuration, the mechanical scanning pitch in the vertical direction and the row pitch b of the two columns on the sensor match through optical reduction, so that the sensor that is advancing in the scanning direction in the external circuit By simply delaying the output by one scanning line using a time memory, etc.
The same effect can be obtained by optically disassembling and optically positioning two conventional sensors. Furthermore, it is clear that if the conditions such as the aperture area of the photoelectric conversion element are the same, the amount of light in the present invention can be reduced to about 1/2.

This is because if the photoelectric conversion element is capacitive like a pn junction photodiode, the light accumulation time can be doubled. The light sensitivity can be doubled compared to using one CCD line sensor, but it is also possible to double the reading speed by keeping the storage time the same.

〔Effect of the invention〕

As explained above, the present invention generates two video signals by forming two sets of CCD line sensors on-chip, and eliminates the mechanical adjustment of the document reading device that was conventionally required. This has the effect of reducing power consumption, downsizing, and power saving.

Furthermore, even if the sensor is simply replaced with a conventional sensor, it is possible to read two lines at the same time, so if the transfer speed of the CCD shift register is the same, the reading speed can be doubled. Alternatively, there is an effect that the sensitivity can be made twice as high.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention;
FIG. 2 is a schematic plan view showing the arrangement of photoelectric conversion elements in an embodiment of the present invention, and FIG. 3 is a block diagram showing the main parts of a conventional example. 1.1.1, 1.2...Photoelectric conversion element array, 2-1゜2
2.2a, 2b-・Shift register, 3-1°32.
3a, 31]-Transfer Game I・, 4.4-+. 4-2... Clock terminal, 5.5 1.5 2... Ratio output circuit, 6.61.6-2... Output terminal. Graduated 1 time, 2 years, 2 years, 3 times

Claims (1)

[Claims] A photoelectric conversion element array in which photoelectric conversion elements are arranged in a line at predetermined intervals, a shift register that receives and transfers charges from the photoelectric conversion elements, and a transfer gate provided between the photoelectric conversion element array and the shift register. 1. A CCD image sensor comprising two sets of single-channel CCD line sensors arranged parallel to each other in plane-symmetrical positions and integrated on a semiconductor substrate.