JPH0414367A - Optical sensor array for image reading - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical sensor array for reading images of a linear image sensor in a facsimile machine or the like.

(Prior Art) A fully contact type linear image sensor, which has an image reading width that is the same as the width of a document, is known as a type of image reading device for facsimiles and the like.

As shown in FIGS. 5 and 6, conventional linear image sensors are arranged in large numbers on an end surface 1a of a substrate 1 parallel to the main scanning direction A of an original O, dividing each pixel of the original into equal intervals. A large number of photoelectric conversion elements 3 are arranged at equal intervals in the main scanning direction A on the substrate 1 with their light receiving surfaces facing substantially parallel to the light incidence end faces 2, and these photoelectric conversion elements It is comprised of an optical waveguide 4 that guides optical information from the document O incident from each light incident end surface 2 to each light receiving surface 3a of the element 3 (Japanese Patent Application Laid-Open Publication No. 189256/1982).

By the way, like this linear image sensor, the original
It is technically difficult to form a single long linear image sensor with a reading width that is the same as the width of the original. If the value is also small, useless image scanning will be performed.

Therefore, in this type of linear image sensor, as shown in FIG. An optical waveguide type optical sensor array 5 is formed, and a plurality of optical sensor arrays 5 are arranged in parallel in the same plane along the main scanning direction A of the original O as shown in FIG. 61-49463 Public Relations) or No. 9
As shown in the figure, a plurality of optical sensor arrays 5 are arranged in a staggered manner along the main scanning direction A of the document ○ (Japanese Patent Laid-Open No. 61-1
42858) to form a linear image sensor with a long reading width.

(Problem to be Solved by the Invention) By the way, as shown in FIG. When forming a linear image sensor, in order to equalize the arrangement pitch P of each light incident end surface 2 of each adjacent optical sensor array 5, the light incident end surfaces located at both ends in the main scanning direction A are Each side edge 2a of 2
and each side edge 1b on both sides of the substrate 1 substantially parallel to the sub-scanning direction B.
The separation distance d from the
/2 pitch or less, each optical sensor array 5
It is necessary to form the substrate 1.

However, in the conventional optical sensor array, the substrate of each optical sensor array 5 is
When the substrate 1 is cut or polished, the photoelectric conversion elements 3 are placed right next to the cut surface □ or the polished surface of the substrate 1, that is, right next to each side edge 1b on both sides of the substrate 1. When cutting or polishing the substrate 1, mechanical stress is applied to the photoelectric conversion element 3, which may cause destruction of the element or deterioration of performance.

In particular, for example, when the pixel bit is 32 dots/mm,
In a high-resolution optical sensor array, it is necessary to cut or polish the substrate 1 so that the above-mentioned separation distance d is at most 15 μm or less, which increases the possibility of destruction of the element or deterioration of performance.

Furthermore, in such a high-resolution optical sensor array, in addition to the photoelectric conversion element 3, an electronic circuit for parking the photoelectric conversion element 3, such as a signal processing circuit such as a shift register, is mounted on one substrate. Since it is often formed on 1,
There is a high possibility that not only the photoelectric conversion element 3 but also elements such as transistors of this electronic circuit will be destroyed or their performance will be deteriorated.

In addition, as a method of preventing destruction and deterioration of the elements due to such mechanical stress, the elements etc. near the cut surface of the substrate 1 are removed in advance to form the optical sensor array 5, and the connecting portions of the optical sensor array 5 are removed. A linear image sensor is known that is configured to compensate for a missing pixel by using image information before and after the missing pixel.

However, this linear image sensor requires a complicated signal processing circuit to compensate for missing pixels, making it impossible to increase the image reading speed.

On the other hand, the linear image sensor shown in FIG.
Since each optical sensor array 5 is arranged in a staggered manner, the substrate 1
Regardless of the shape of the pixel, the pixel pitch at the connecting portion can be set arbitrarily.

Therefore, in this linear image sensor, each side edge 2a of the light incident end face 2 located at both ends in the main scanning direction A of each photosensor array 5 and each side edge 2a of the light incident end surface 2 located at both ends in the main scanning direction A, and each side edge 2a on both sides of the substrate 1 substantially parallel to the sub scanning direction B. The distance d from the side edge 1b can be set to a sufficient distance that does not affect the photoelectric conversion element 3.

However, with this linear image sensor.

Since positional shifts occur in the reading positions of pixels in the main scanning direction A for each optical sensor array 5, it is necessary to rearrange the read optical information and then supply it as an external signal.

For this reason, for example, when this linear image sensor is a completely contact type linear image sensor, the length t of the substrate 1 in the sub-scanning direction is usually about 1 to 5, so that adjacent A positional shift of about 11 to 5 degrees also occurs in the reading positions of pixels in the main scanning direction A of the optical sensor array 5.

Here, in order to maintain the resolution, the accuracy of correcting the positional deviation of pixels in the main scanning direction A is at least equal to or less than the image reading pitch in the main scanning direction A (preferably, 1/3 or less of the image reading pitch). ).

Therefore, for example, if the pixel bit is 32 dots/m,
In a high-resolution optical sensor array, the image reading pitch is about 30 μm, so it is desirable that the pixel positional deviation correction accuracy in the main scanning direction A is 10 μm or less.

However, in reality, positional deviations are added due to the conveyance accuracy of document ○ and the occurrence of expansion or contraction of document 0 when reading optical information, so as mentioned above, it is necessary to Under the present circumstances, it is difficult to correct a positional deviation of IIW~5 ml in the reading position of a pixel in the main scanning direction A with an accuracy of 10 μm or less.

The present invention has been made in view of the above points, and an object of the present invention is to read an image that can easily configure a long linear image sensor that does not require correction of pixel positional deviation in the main scanning direction. An object of the present invention is to provide a photosensor array for use.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a large number of light incident end faces arranged at equal intervals on a substrate end face parallel to the main scanning direction, and A large number of photoelectric conversion elements are arranged at regular intervals in the main scanning direction on the substrate with their light-receiving surfaces substantially parallel to each other, and optical information is incident on each of the light-receiving surfaces of these photoelectric conversion elements from each of the light incident end faces. In the image reading optical sensor array having an optical waveguide for guiding the light, each side edge of the light incident end face located at both ends in the main scanning direction and each side edge on both sides of the substrate substantially parallel to the sub-scanning direction; The distance between them is less than or equal to 1/2 pitch of the arrangement pitch of each of the light incident end faces, and the distance is approximately parallel to each side edge of the photoelectric conversion element located at both ends in the main scanning direction in the sub-scanning direction. The distance from each side edge on both sides of the substrate is set to a value larger than 1/2 pitch of the arrangement pitch of each of the light incident end faces.

(Function) According to the present invention, each side edge #2a of the light incident end surface 2 located at both side edges in the main scanning direction A and each side edge 1b on both sides of the substrate 1 substantially parallel to the sub-scanning direction B. Since the separation distance d from the light incident end surface 2 is set to a value equal to or less than 1/2 pitch of the arrangement pitch P of each light incident end surface 2, a plurality of optical sensors are arranged in the same plane along the main scanning direction A of the document 0. A long linear image sensor without positional deviation in the main scanning direction A is formed by arranging the arrays 5 in parallel.

Further, according to the present invention, each side edge 3b of the photoelectric conversion element 3 located at both ends in the main scanning direction A and each side edge 1b on both sides of the substrate 1 substantially parallel to the sub-scanning direction B are connected to each other. The separation distance g is
Since the array pitch p of each light incident end face 2 is larger than 1/2 pitch, the substrate 1 of each optical sensor array 5
The influence of mechanical stress on the photoelectric conversion element 3 during cutting or polishing is reduced.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

However, in order to avoid complicating the explanation, illustrations and disclosures thereof will be omitted to avoid complicating the explanation, as well as the configuration and operation within the range that can be clearly recalled from the description of this specification, as well as the above-mentioned and other objects and novel features of the present invention. , or simplify it.

In addition, among the configurations of each part in this example, members having the same or substantially similar functions as the configuration of each part in the conventional example are designated with the same reference numerals as those given to the members in each of the previous examples. Omit or simplify the explanation.

In the present invention, the optical waveguide 4 of the optical sensor array 5 described above is
The photoelectric conversion element 3 and elements such as transistors in the electronic circuit that drives this photoelectric conversion element 3 This was done in view of the large deterioration of characteristics due to mechanical and thermal stress.

That is, the materials for the leading waveguide 4 of the optical sensor array 5 are usually MgO, S i O,, S i , N4゜5.
iON films are used, but these materials are composed of chemically stable oxides and nitrides, so they have relatively strong characteristics against mechanical and thermal stress. .

On the other hand, the photoelectric conversion elements 3 of the optical sensor array 5 and the electronic elements 6 (such as transistors) constituting the electronic circuit for driving them (
(see Figure 5) is strongly affected by mechanical and thermal stress because its performance is determined by physical properties such as the energy band state and interface state of each element, which is mechanically and thermally unstable. .

By the way, when producing the above-mentioned short optical sensor array 5, in order to improve production efficiency, a large number of optical sensor arrays 5 are usually formed on a 4-inch or 6-inch long wafer. After creating the wafer, each optical sensor array 5 is cut out from the wafer using a dicing saw or the like.

When cutting this wafer, in order to prevent mechanical and thermal stress from being applied to the photoelectric conversion elements 3 of the optical sensor array 5 and the electronic elements 6 such as transistors that constitute the electronic circuit for driving them, - For boat fishing, it is recommended that the formation area of each optical sensor array 5 be provided at a location sufficiently away from the side edge of the cut surface of the wafer.

However, as described above, when a plurality of short optical sensor arrays 5 are arranged in parallel to form one long linear image sensor, the photoelectric conversion elements 3 of each optical sensor array 5 and their Since the wafer must be cut in close proximity to the electronic elements 6 such as transistors that constitute the driving electronic circuit, there is a great possibility that the elements may be destroyed or their performance deteriorated.

Therefore, in the present invention, as shown in FIG.
2 a and each side edge 1b on both sides of the substrate 1 that is substantially parallel to the sub-scanning direction B, the distance d is set to a value equal to or less than 1/2 pitch of the arrangement pitch P of each light incident end surface 2, In addition, each side edge 3 of the photoelectric conversion element 3 located at both ends in the main scanning direction A
b and the respective side edges 1b on both sides of the substrate 1 that are substantially parallel to the sub-scanning direction B, the distance g is determined by the arrangement pitch P of each light incident end surface 2.
Set it to a value larger than 1/2 pitch.

According to the optical sensor array 50 configured in this way, each side edge 2a of the light incident end face 2 located at both ends in the main scanning direction A, and both sides of the substrate 1 substantially parallel to the sub-scanning direction B are Since the distance d from each side edge 1b is set to a value equal to or less than 1/2 pitch of the arrangement pitch p of each light incident end surface 2, it is possible to By arranging a plurality of optical sensor arrays 50 in parallel, a long linear image sensor with no displacement in the main scanning direction A can be easily formed.

Moreover, according to the optical sensor array 50 configured in this way, each side edge 3b of the photoelectric conversion element 3 located at both ends in the main scanning direction A and both sides of the substrate 1 substantially parallel to the sub-scanning direction B Since the separation distance g from each side edge Il#lb is formed to a value larger than 1/2 pitch of the arrangement pitch P of each light incident end surface 2, the photoelectric conversion elements 3 of the optical sensor array 50,
The cut or polished surface of the substrate 1 can be separated from the arrangement position of the electronic elements 6 such as transistors constituting the driving electronic circuit, and each optical sensor array 5
The influence of mechanical stress on the photoelectric conversion element 3 and the like during cutting or polishing of the substrate 1 of 0 is reduced.

Here, the photoelectric conversion element 3 is a CdS, amorphous silicon, or PIN photodiode.

Elements such as CCD and SIT are used.

Among these elements, amorphous silicon has relatively high strength against mechanical stress compared to other elements, so when amorphous silicon is used as the photoelectric conversion element 3, As such, only the electronic elements 6 such as transistors of the electronic circuit that drives the photoelectric conversion element 3 may be provided as a photosensor array 51 separated from both side edges 1b of the substrate 1.

Here, as the electronic element 6 such as a transistor of the electronic circuit that drives the photoelectric conversion element 3, for example, a single crystal silicon transistor, amorphous silicon TPT, polysilicon TPT, S○I TFT, etc. are used.

Furthermore, among the above-mentioned materials, 5iON film is particularly suitable as the material for the optical waveguide 4 of the optical sensor array according to the present invention.

The reason for this is that the refractive index of this 5iON film can be easily changed by controlling the ratio of oxygen and nitrogen.

■Si contains dangling bonds, which acts as a buffer against mechanical stress and prevents cracks from forming in the film.

■High melting point and high resistance to thermal stress.

It has various advantages such as.

Further, the shape of the optical waveguide 4 may be a shape having a gentle S-shaped curved part as shown in FIG. 1, or a shape having a gentle rank shape as shown in FIG. It may also have a linear shape as shown in FIG.

Here, if there is a bending point in the optical waveguide 4 or if the optical path length becomes long, a certain amount of light loss will occur.
The efficiency of transmitting optical information to the photoelectric conversion element 3 will decrease to some extent, but if this affects the gradation during image reading, for example, if the optical waveguide 4 and the photoelectric conversion element 3 By intentionally changing the coupling efficiency of light, it is possible to ensure a uniform amount of photoelectric conversion with respect to the amount of light incident on the light incident end face 2 of the optical waveguide 4.

(Effects of the Invention) According to the present invention, it is possible to easily form a long linear image sensor without positional deviation in the main scanning direction, and when cutting or polishing the substrate of each optical sensor array,
A highly reliable optical sensor array in which photoelectric conversion elements and the like are not easily affected by mechanical stress can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of one embodiment of the present invention, FIG. 2 is a schematic plan view of another embodiment of the present invention, FIG. 3 is a schematic plan view of still another embodiment of the present invention, and FIG. 5 is a schematic side view of a conventional optical sensor array, FIG. 6 is a schematic plan view of a conventional linear image sensor, and FIG. 7 is a schematic plan view of a conventional optical sensor array. FIG. 8 is a schematic plan view of another conventional linear image sensor, and FIG. 9 is a schematic front view of still another conventional linear image sensor. DESCRIPTION OF SYMBOLS 1... Substrate, 1b... Side edge of substrate 1, 2... Light incidence end face, 2a... Side edge of light incidence end face 2, 3...
Photoelectric conversion element, 3b...Side edge of photoelectric conversion element 3, 4
...Optical waveguide, 6...Electronic element, 50.51...
Optical sensor array, A... Main scanning direction, B... Sub-scanning direction, d... Separation distance between the side edge 2a of the light incident end face 2 and the side edge 1b of the substrate 1, g... The distance between the side edge 3b of the photoelectric conversion element 3 and the side edge @lb of the substrate 1. Previous ward % U Figure 93 Ward % 4 Figure % 8 Matabei 9

Claims (1)

[Claims] 1. A large number of light incident end faces arranged at equal intervals on the end face of the substrate parallel to the main scanning direction, and a light receiving surface facing substantially parallel to these light incident end faces, In an optical sensor array for image reading, which has a large number of photoelectric conversion elements arranged at equal intervals in a scanning direction, and an optical waveguide that guides optical information incident from each of the light incident end faces to each light receiving surface of these photoelectric conversion elements. , the distance between each side edge of the light incident end face located at both ends in the main scanning direction and each side edge on both sides of the substrate substantially parallel to the sub scanning direction is 1 of the arrangement pitch of each of the light incident end faces.
/2 pitch or less, and the distance between each side edge of the photoelectric conversion element located at both ends in the main scanning direction and each side edge on both sides of the substrate substantially parallel to the sub-scanning direction is set as above. A photosensor array for image reading, characterized in that the pitch is larger than 1/2 of the arrangement pitch of each light incident end face. 2. A large number of light incident end faces arranged at equal intervals on the end face of the substrate parallel to the main scanning direction, and a light receiving face facing substantially parallel to these light incident end faces and arranged at equal intervals in the main scanning direction on the substrate. It has a large number of photoelectric conversion elements arranged, an optical waveguide that guides optical information incident from each of the light incident end faces to each light receiving surface of these photoelectric conversion elements, and an electronic circuit that drives each of the above photoelectric conversion elements. In the optical sensor array for image reading, the photoelectric conversion elements are formed of amorphous silicon, and the photoelectric conversion elements are formed of amorphous silicon, and each side edge of the light incident end face located at both ends in the main scanning direction and the substrate on both sides substantially parallel to the sub-scanning direction are formed. The distance from each side edge is 1 of the arrangement pitch of each light incident end face.
/2 pitch or less, and the distance between each side edge of the electronic element of the electronic circuit located at both ends in the main scanning direction and each side edge on both sides of the substrate substantially parallel to the sub-scanning direction. An optical sensor array for image reading, characterized in that the distance is set to a value larger than 1/2 pitch of the arrangement pitch of each of the light incident end faces.