JPH0797631B2 - Image sensor - Google Patents

Description

The present invention relates to an image sensor for detecting optical information having a one-dimensional or two-dimensional spatial distribution.

[Outline of Invention]

According to the present invention, in the image sensor as described above, a plurality of photosensors that can operate independently of each other are arranged in a plane in which a region occupied by a pattern in which a plurality of photoelectric conversion elements are arranged is perpendicular to the stacking direction. By stacking the layers so that they are different from each other, highly accurate detection can be performed at high speed and the manufacturing cost can be reduced.

[Conventional technology]

FIG. 3 shows a conventional example of a two-dimensional image sensor. In this conventional example, as shown in FIG. 3A, a substrate 11 and a thin film optical sensor 21a formed in contact with the substrate 11 are provided.
And have. The substrate 11 is a support for the optical sensor 21a, and is made of glass, ceramic, semiconductor, or the like.

As shown in FIG. 3B, the optical sensor 21a includes a large number of photoelectric conversion elements 22a as picture elements and scanners 23a and 24a for reading out signals converted from light to electricity by these photoelectric conversion elements 22a. Have

The optical information is input to the image sensor from the optical sensor 21a side, or when the substrate 11 has a light-transmitting property, this substrate is used.
It is done from the 11th side.

By the way, in order to input a document image with an image sensor and recognize the image as a character, it is necessary to compare the input image with a reference character pattern.

Prior to this comparison, it is necessary to know the inclination (rotation) of the character string, the center position of the character, the size of the character, the inclination of the character itself, the rotation of the character itself, and the like.

However, in the above-mentioned conventional image sensor, the scanner
The electric signal read from 23a, 24a is input to a computer (not shown) and a calculation process is performed to obtain the inclination of the character string and the like.

[Problems to be solved by the invention]

However, it takes a lot of time to perform the calculation processing of all the signals obtained from the large number of photoelectric conversion elements 22a, and the characters cannot be recognized at high speed.

Further, in order to increase the detection accuracy of the image sensor, it is necessary to increase the surface density of the photoelectric conversion element 22a, but in that case, the detection operation becomes further slower and the manufacturing cost of the image sensor sharply increases. These problems occur not only when detecting a document image but also when detecting general optical information.

[Means for solving problems]

In the image sensor according to the present invention, a plurality of photosensors 21a to 21c, 41a, 41b that can operate independently of each other are stacked, and a plurality of photoelectric conversions in each of the photosensors 21a to 21c, 41a, 41b. The areas occupied by the pattern formed by arranging the elements 22a to 22c, 43a, 43b are different from each other in a plane perpendicular to the stacking direction.

[Action]

In the image sensor according to the present invention, a single optical information can be simultaneously detected by a plurality of optical sensors 21a to 21c, 41a, 41b in mutually different planar patterns, and a function necessary for detecting the optical information. And performance of each optical sensor 21
It can be shared by a to 21c, 41a and 41b.

〔Example〕

Hereinafter, first and second embodiments of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows the first embodiment. As is clear from FIGS. 1A and 1D, the first embodiment is a thin film optical sensor having two layers between the substrate 11 and the optical sensor 21a in the conventional example shown in FIG. 21b and 21c are interposed. That is, in this embodiment, the optical sensors 21b, 21c and 21a are sequentially laminated on the substrate 11.

As shown in FIG. 1B, the optical sensor 21b has, for example, photoelectric conversion elements 22b that are relatively dense in the x-axis direction and are rough in the y-axis direction. As shown in C, x
Photoelectric conversion element 22c that is coarse in the axial direction and relatively dense in the y-axis direction
have. The photoelectric conversion element 22a of the optical sensor 21a is
Photoelectric conversion element in both the x-axis direction and the y-axis direction
It is denser than both 22b and 22c.

And the optical sensors 21b and 21c are also the other optical sensors 21c, 21b and
Scanner 23b, so that it can operate independently of 21a,
It has 24b, 23c, and 24c.

For example, when recognizing a character using the first embodiment as described above, the optical sensor 21b can detect the approximate size and center position of the character in the y-axis direction at high speed, and also in the x-axis direction. The approximate size and center position can be detected at high speed by the optical sensor 21c.

Moreover, since the optical sensors 21b and 21c can operate independently of each other, by performing the detection operations of both in parallel, the approximate size of the character to be recognized, the center position, and the like can be detected very quickly.

Furthermore, when the character is accurately recognized by the optical sensor 21a, the calculation processing is performed only on the signal from the photoelectric conversion element 22a in the area corresponding to the size of the character obtained by the optical sensors 21b and 21c. Character recognition is extremely fast.

That is, in the first embodiment, the optical sensors 21b, 21c, 21 are provided with the function of extracting the feature in the y-axis direction, the function of extracting the feature in the x-axis direction, and the function of extracting the overall feature.
a is in charge of each.

It should be noted that separate optical sensors may share the function of extracting features in the diagonal direction and the radial direction of the concentric circles as well as the x-axis direction and the y-direction.

Furthermore, if the type, size, etc. of the optical information to be detected are limited, the function of directly extracting the characteristics of the optical information, such as a character pattern, can be shared by separate optical sensors. By doing so, calculation processing by a computer becomes unnecessary, and optical information can be detected at higher speed.

FIG. 2 shows a second embodiment. In the second embodiment, thin-film optical sensors 41a and 41b formed in contact with glass substrates 31a and 31b are laminated with a spacer 42 interposed therebetween. In the photosensors 41a and 41b, photodetecting portions 43a and 43b and separating portions 44a and 44b having the same width are formed in a stripe shape.

The photosensors 41a and 41b are laminated so that the photodetection units 43a and 43b on one side and the separation units 44a and 44b on the other side face each other. Therefore, when the photodetectors 43a and 43b are viewed through the substrates 31a and 31b from the direction perpendicular to the substrates 31a and 31b, the photodetectors 43a and 43b are arranged side by side without any gap.

Therefore, in the second embodiment, optical information can be detected without omission, and highly accurate detection can be performed. That is, in the second embodiment, the two optical sensors 41a and 41b share the performance for detecting optical information.

Moreover, even if the stripe widths of the photodetectors 43a and 43b are widened, that is, the photodetectors 43a and 43b are not precisely formed, the above-described highly accurate detection can be performed. Therefore this second
Embodiments may be manufactured at low cost.

The optical sensor 21a according to the first and second embodiments described above
As the elements 21c, 41a, 41b, a conventionally known MOS image sensor, CCD image sensor, or the like can be used.

Further, in the above first and second embodiments, the optical sensors 21a-21
Although c, 41a, and 41b are formed as a thin film integrated circuit and these thin films are laminated on each other, the optical sensor may be formed as an integrated circuit in a semiconductor substrate and these semiconductor substrates may be laminated on each other.

〔The invention's effect〕

In the image sensor according to the present invention, a single optical information can be simultaneously detected by a plurality of optical sensors in mutually different planar patterns, so that the detection operation of each optical sensor can be performed in parallel and one-dimensional Alternatively, the optical information having a two-dimensional spatial distribution can be detected at high speed.

Moreover, since the functions and performances necessary for detecting optical information can be shared by the respective optical sensors, the functions and performances of the respective optical sensors can be simplified and the detection operation can be performed at high speed. In addition, the manufacturing cost can be reduced. Moreover, even if the function and performance of each optical sensor is simple, by combining each function and performance,
Highly accurate detection can be performed.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention.
FIG. A is an overall perspective view of the first embodiment, and FIGS. 1B to 1D are first perspective views.
FIG. 2 is a perspective view of each part of the embodiment, and FIG. 2 is a side sectional view of the second embodiment. FIG. 3 shows a conventional example of the present invention. FIG. 3A is an overall perspective view and FIG. 3B is a partial perspective view. In the reference numerals used in the drawings, 21a to 21c ... Optical sensors 41a, 41b ... Optical sensors.

Claims (3)

[Claims] 1. A plurality of photosensors that can operate independently of each other are stacked, and an area occupied by a pattern formed by arranging a plurality of photoelectric conversion elements in each of the plurality of photosensors is in the stacking direction. Are image sensors that are different from each other in a vertical plane. 2. The optical sensor according to claim 1, wherein the plurality of optical sensors have the different patterns, and the plurality of optical sensors have different functions by the different patterns. Image sensor. 3. The plurality of photosensors are composed of first and second photosensors having the same stripe-shaped pattern, and the first and second photosensors are arranged so that the stripe-shaped patterns are alternately opposed to each other. The image sensor according to claim 1, wherein the two optical sensors are stacked on each other.