JPH0983729A - Contact image sensor and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact image sensor and its production to prevent the deterioration of resolution at a joint part between the light receiving sensor elements. SOLUTION: A contact image sensor consists of a light source which irradiates an original, plural light receiving sensor elements 11 which convert the reflected light of the original into the electric signals, and light waveguide array 6 which includes plural light waveguides 7 arranged in an array to lead the reflected light of the original to the elements 11. Then the array 6 is divided into groups in the same number as the elements 11, and the pitch of a light receiving window 11a is reduced at the side of the elements 6 in comparison with the pitch of the light receiving window on the original side in every group. Thus every waveguide 7 is tapered and therefore the gaps are secured among the elements 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type image sensor used in a document reading section of a facsimile, an image scanner, a copying machine or the like, and a manufacturing method thereof.

[0002]

2. Description of the Related Art FIG. 12 is a sectional view of a main part of a conventional contact type image sensor. The contact type image sensor having such a structure reflects the light emitted from the LED line light source 1 on the original 2 and reflects light including characters and image information as an erecting equal-magnification optical system. An image is formed on the light-receiving surface of the light-receiving sensor element 4 by 3 and converted into an electric signal, and then output through the substrate 5 or a reading circuit formed outside.

In such a conventional contact type image sensor, the rod lens array 3 has a distributed refractive index type erecting equal-magnification in which the central refractive index is large and the refractive index gradually decreases toward the outside. An array of imaging lenses is used, and the conjugate length of the optical system (distance from the original 2 to the light receiving sensor element 4) is ten to several tens m.
m.

A crystal semiconductor bipolar or CMOS is used as the light-receiving sensor element 4, and a plurality of these light-receiving sensor elements 4 are arranged in a straight line on the substrate 5 to form an array, and at least the same width as the original 2 is secured. The light-receiving sensor array has a multi-chip configuration.

Therefore, for example, if the light receiving sensor element 4 in which 64 pixels per element are formed at a pitch of 125 μm is used, 27 pieces are read on the A4 short side width, and 32 pieces are read on the B4 short side width on a straight line. By placing, 8 dots
A light receiving sensor array having a resolution of / mm (equivalent to 200 DPI) can be configured. Also, 16 dot / mm (400
In the case of a resolution equivalent to DPI), 6 per element similarly.
The same number of light receiving sensor elements 4 each having four pixels formed at a pitch of 62.5 μm are used. With such a configuration, in the joint between the light receiving sensor elements 4 arranged on the substrate 5 in a straight line, the distance between the pixels at the outermost ends is 125 μm or 62.
It is necessary to set the thickness to about 5 μm, and high precision is required when cutting the light receiving sensor material as a material into the light receiving sensor element 4 and mounting on the substrate 5.

[0006]

However, in the conventional contact type image sensor as described above, since a plurality of light receiving sensor elements 4 are arranged in a straight line to form a light receiving sensor array, the light receiving sensor elements 4 are inevitably arranged between them. A slight gap is generated, and the distance between the pixels at the outermost end exceeds the predetermined value at the joint portion of the light receiving sensor element 4, resulting in a decrease in resolution. Also, since this void is accumulated by the number of seams,
The higher the pixel density, the greater the influence of the gap, and there is a problem in that the reading accuracy is greatly disturbed over the entire reading width.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a contact type image sensor in which the deterioration of the resolution at the joint portion of the light receiving sensor element is prevented.

[0008]

In order to solve the above problems, a contact type image sensor of the present invention comprises a light source for illuminating a document and a plurality of light receiving sensor elements for converting light reflected from the document into an electric signal. And an optical waveguide array in which a plurality of optical waveguides for guiding the reflected light from the original to the light receiving sensor element are arranged in an array, and the optical waveguide array is divided into the same number of groups as the light receiving sensor element, and the original is set for each group. The pitch of the light receiving window on the side of the light receiving sensor element is narrower than the pitch of the light receiving window on the side to form the optical waveguide in a tapered shape, and a gap is provided between each element of the plurality of light receiving sensor elements.

[0009]

With this structure, the allowable range of positional deviation at the time of mounting the light receiving sensor element is widened, so that there is virtually no positional deviation, and it is possible to prevent deterioration of the resolution at the joint portion of the light receiving sensor element.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a perspective view of a main part of a contact image sensor according to the first embodiment of the present invention, and FIG. 2 is a contact image sensor according to the first embodiment of the present invention. FIG. 6 is an enlarged plan view of a joint portion of a light receiving sensor element. 1 to 2, the light source for illuminating the original is omitted.

1 and 2, reference numeral 6 denotes an optical waveguide array, which is composed of an optical waveguide 7, a light-shielding clad portion 8 for separating the optical waveguide 7, and a lower surface clad layer 9 and an upper surface clad layer 10. . The one-dimensional light receiving sensor element 11 is composed of a crystal semiconductor bipolar or CMOS, and converts the reflected light from the original 2 guided by the optical waveguide 7 into an electric signal. Each pixel of the light receiving sensor element 11 is arranged in an array according to a desired resolution, and a plurality of light receiving sensor elements 11 are arranged in a line according to the specifications of the reading width to form an array to form a light receiving sensor array. are doing. Reference numeral 12 is a substrate on which a circuit portion 13 is printed. The circuit portion 13 is a sensor driving circuit for driving the light receiving sensor element 11, a reading circuit for outputting an electric signal from the light receiving sensor element 11, and a light source driving for driving a light source (not shown). It is composed of a circuit and the like. When the optical waveguide array 6 and the light receiving sensor element 11 are formed on the substrate 12, the main part of the contact image sensor is completed.

As described above, in the conventional example shown in FIG.
At the joint between the light receiving sensor elements 4, for example, a resolution of 2
With 00 DPI (8 dots / mm), it is necessary to set the distance between the pixels at the outermost end to about 125 μm, which requires high accuracy when cutting or mounting the light receiving sensor element 4 itself.

On the other hand, in the present embodiment, the pixel pitch of the light receiving sensor element 11 is made slightly narrower, for example, 1 μ for 200 DPI.
Pixels are formed with a pitch of 124 μm by narrowing the pitch by m. Therefore, at the joint of the light receiving sensor element 11, the pixels at the outermost ends have a space of 188 μm,
There is a margin of 60 μm or more as compared with the conventional case of 125 μm. This size is sufficient for the mounting accuracy of the current semiconductor chip mounting machine, and the light receiving sensor element 11 is mounted on the substrate 12
However, it is possible to perform accurate positioning, and it is possible to accommodate the deviation of the reading position in the entire reading width due to the accumulation of air gaps between the light receiving sensor elements 11 within the mounting accuracy of a single element.

Further, the above contents will be described in detail with reference to FIG. FIG. 2 is an enlarged plan view showing a state in which the upper cladding layer 10 is removed from FIG. Reference numeral 11a is a light receiving window corresponding to each pixel of each light receiving sensor element 11. Although three optical waveguides 7 are formed for one light receiving window 11a, the number of optical waveguides 7 may be one or may be any other number. However, in order to prevent a significant decrease in the amount of incident light with respect to the relative displacement between the light receiving sensor element 11 and the optical waveguide array 6, a plurality of optical waveguides 7 may be formed for one light receiving window 11a. desirable.

The light receiving sensor element 11 in this embodiment is
Since the resolution is 200 DPI, each element has 64 pixels, and the light receiving window 11a corresponding to each pixel is 124 μm.
They are formed at an m pitch. Therefore, the total length is 64 μm shorter than the conventional element formed with a pitch of 125 μm,
It becomes 32 μm shorter at both ends. Therefore, the distance between the pixels at the joint between the two light receiving sensor elements 11 is 1
It becomes 88 μm.

On the other hand, in the optical waveguide array 6, the three optical waveguides 7 correspond to one pixel, and 64 pixels correspond to one light receiving sensor element 11 as one optical waveguide group, so that the light receiving window 11a is formed. It is formed in a taper shape with a 124 μm pitch on the side and a 125 μm pitch on the read document side.

With the above configuration, the relative positions of the individual light receiving sensor elements 11 and the divided optical waveguide array corresponding to the light receiving sensor elements 11 can be obtained without accumulating voids between the light receiving sensor elements 11. The accuracy can be kept within the mounting accuracy of a semiconductor chip mounting machine such as a die mounter.

In this embodiment, the optical waveguide array 6 is used in the optical system. Therefore, if the length of the optical waveguide array 6 is shortened, the conjugate length of the optical system can be shortened as compared with the conventional example, and the product can be downsized.

(Embodiment 2) FIG. 3 is an enlarged plan view of a joint portion of a light receiving sensor element of a contact image sensor according to a second embodiment of the present invention. Note that, as in FIG. 2, a state in which the upper surface clad layer 10 is removed is shown. In the figure, only the light receiving windows 11a at both ends of each light receiving sensor element 11 are arranged at intervals of 83 μm, which is inwardly shifted by about 41 μm, which is the thickness of one optical waveguide 7.

With the above configuration, the relative positions of the individual light receiving sensor elements 11 and the divided optical waveguide array 6 corresponding to the light receiving sensor elements 11 may shift due to the mounting displacement of the semiconductor chip mounting machine such as a die mounter. Even
Since the optical waveguide 7 is arranged in the entire light receiving window of the light receiving windows 11a of the pixels at both ends of each light receiving sensor element 11, it is possible to prevent a decrease in the amount of light in the pixels at both ends of each light receiving sensor element 11.

The above pitch correction distance (41 μm)
Is not limited to the above example, and the pitch can be adjusted according to the mounting accuracy of the semiconductor chip mounting machine. Also, 4
In the case of other resolutions such as 00 DPI, the pitch can be adjusted similarly.

In this embodiment, the optical waveguide array 6 is used in the optical system. Therefore, if the length of the optical waveguide array 6 is shortened, the conjugate length of the optical system can be shortened as compared with the conventional example, and the product can be downsized.

(Embodiment 3) Next, a method of manufacturing a contact image sensor according to an embodiment of the present invention will be described. 4 to 7 are manufacturing process diagrams of main parts of the method of manufacturing the contact image sensor according to the embodiment of the present invention.

As shown in FIG. 4, a plurality of light receiving sensor elements 11 are mounted by a die mounter or the like on a substrate 12 on which wiring for forming a circuit portion 13 (see FIG. 1) is provided in advance. At that time, positioning is accurately performed with respect to the reference point formed on the substrate 12, and the light receiving sensor element 11 and the substrate 12 are electrically connected by a wire bonding method or the like.

Next, as shown in FIG. 5, a lower surface clad layer 9 for forming the optical waveguide 7 is formed by a mold resin molding method, which simultaneously serves as a protective layer for protecting the light receiving sensor element 11. Also fulfills. As a resin curing method, an ultraviolet curing method, an electron beam curing method, or a heat curing method may be used depending on the material of the substrate 12. Here, when the mold resin molding method is performed using a transparent stamper as described later, since it is transparent and ultraviolet rays can be irradiated from the entire circumference of the stamper, even if the substrate 12 as the transfer surface is an opaque substrate. Resin transfer becomes possible.

Further, as shown in FIG. 6, the optical waveguide 7 is formed by the same mold resin molding method as that used for forming the lower clad layer 9.

Finally, as shown in FIG. 7, the optical waveguide 7 is separated and the upper clad layer 10 is formed. In addition, the light-shielding clad portion 8 integrated with the upper surface clad layer 10 is simultaneously formed in the recessed portion after the optical waveguide 7 is separated. As a forming method, the same mold resin molding method as when the lower surface clad layer 9 is formed, or a coating method, a dipping method, or the like is used. Further, if necessary, post-processing such as cutting and polishing the end surface of the optical waveguide array 6 on the side of the read document or abrasion resistance processing can be performed.

Here, a method of forming a stamper used in the molding resin molding method for the upper clad layer 10 and the optical waveguide 7 will be described. 8 to 11 are manufacturing process diagrams of the stamper used in the manufacturing process of the main part of the manufacturing method of the contact image sensor according to the embodiment of the present invention.

As a first manufacturing method, as shown in FIG. 8, the master mold 14 is made by manufacturing the stamper 17 to be manufactured from phosphor bronze. Next, as shown in FIG. 9, the master mold 14 is immersed in the uncured thermosetting resin 16 in the mold 15 and left at room temperature for 24 hours to cure the thermosetting resin 16. Examples of the thermosetting resin 16 include epoxy resin, polyurethane resin, acrylic resin, etc. Among them, acrylic resin is most suitable because it has good light transmittance. As a specific thermosetting resin,
For example, Dainippon Ink and Chemicals Akridic A-8
01 (90 copies), Burnock DN-950 (10 copies),
Xylene (20 parts) is used. After curing the thermosetting resin 16, the master mold 14 is carefully removed, and
As shown in FIG. 5, a stamper 17 which is a transparent resin mold obtained by transferring the shape of the master mold 14 is obtained.

As the second manufacturing method, glass is RIE.
To form the shape shown in FIG.
Anneal at 00 ° C. for 2 hours. Thus, the stamper 18 as a transparent glass mold is obtained. Examples of the glass include soda lime glass, borosilicate glass, lead glass, aluminosilicate glass, and soda lime glass is preferably used.

As a third manufacturing method, a master mold 14 is manufactured by previously manufacturing a mold having the shape shown in FIG. 8 from phosphor bronze.
Next, an electron beam curable resin is used instead of the thermosetting resin 16 shown in FIG. 9, the master mold 14 is dipped in the uncured electron beam curable resin in the mold 15, and the Cockcroft type electron beam is used. An electron beam of 10 megarad is irradiated by the generator to cure the electron beam curable resin. As the electron beam curable resin, for example, Gosslac UV-700 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.
0B (50 parts), Toagosei Kagaku Kogyo Aronix M-
5700 (50 parts) are used. After the electron beam curable resin is cured, the master mold 14 is carefully removed, and as shown in FIG.
As shown in FIG. 5, a stamper 17 which is a transparent resin mold obtained by transferring the shape of the master mold 14 is obtained.

As a fourth manufacturing method, a master mold 14 is manufactured by previously manufacturing a mold having the shape shown in FIG. 8 from phosphor bronze. Next, instead of the thermosetting resin 16 shown in FIG.
The master mold 14 is immersed in an uncured ultraviolet curable resin therein, and the ultraviolet curable resin is cured by irradiating it with 700 MJ / cm ² of ultraviolet rays by a high pressure mercury lamp. Examples of the ultraviolet curable resin include Unidick 15-829 (50 parts) manufactured by Dainippon Ink and Chemicals, 1-hydroxy-1-
Cyclohexylacetophenone (4 parts) and Aronix M-5700 (50 parts) manufactured by Toagosei Chemical Industry are used. After the UV curable resin is cured, the master mold 14 is carefully removed, and as shown in FIG.
A transparent resin stamper 17 in which the shape of No. 4 is transferred is obtained.

Examples of the electron beam curable resin and ultraviolet curable resin used in the third and fourth manufacturing methods include resins containing an ethylenically unsaturated group. Specifically, a resin obtained by condensing (meth) acrylic acid on polyester, an ethylenically unsaturated group-containing polyurethane resin, an ethylenically unsaturated group-containing epoxy resin, an ethylenically unsaturated group-containing phosphorus epoxy resin, an ethylenically unsaturated Examples include group-containing acrylic resins, ethylenically unsaturated group-containing silicone resins, ethylenically unsaturated group-containing melamine resins, and the like. In particular, a polyurethane resin having a (meth) acrylic group, that is, a urethane acrylate resin is most suitable because it has good shape transfer properties and releasability.

Using the stampers 17 and 18 manufactured by the above-mentioned four manufacturing methods, resin was formed on the silicon wafer, the gallium-arsenic wafer and the glass-epoxy substrate by the mold resin molding method. As a result, the master mold was obtained. A good resin shape similar to that of No. 14 could be formed.

[0036]

According to the contact image sensor of the present invention, a light source for irradiating a document, a plurality of light receiving sensor elements for converting the reflected light from the document into an electric signal, and the reflected light from the document are guided to the light receiving sensor element. An optical waveguide array in which a plurality of optical waveguides are arranged in an array is provided, and the optical waveguide array is divided into the same number of groups as the light receiving sensor elements, and each group receives light on the light receiving sensor element side from the pitch of the light receiving window on the document side. The window pitch was narrowed to form the optical waveguide in a tapered shape, and a gap was provided between each of the plurality of light receiving sensor elements.

With this configuration, the permissible range of positional deviation at the time of mounting the light receiving sensor element is widened, so that there is virtually no positional deviation, and it is possible to prevent deterioration of the resolution at the joint portion of the light receiving sensor element.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a contact image sensor according to a first embodiment of the present invention.

FIG. 2 is an enlarged plan view of a joint portion of the light receiving sensor element of the contact image sensor according to the first embodiment of the present invention.

FIG. 3 is an enlarged plan view of a joint portion of a light receiving sensor element of a contact image sensor according to a second embodiment of the present invention.

FIG. 4 is a manufacturing process diagram of a main part of a method of manufacturing a contact image sensor according to an embodiment of the present invention.

FIG. 5 is a manufacturing process diagram of a main part of a method of manufacturing a contact image sensor according to an embodiment of the present invention.

FIG. 6 is a manufacturing process diagram of the main part of the method for manufacturing the contact image sensor according to the embodiment of the present invention.

FIG. 7 is a manufacturing process diagram of a main part of the method of manufacturing the contact image sensor according to the embodiment of the present invention.

FIG. 8 is a manufacturing process diagram of a stamper used in a manufacturing process of a main part of a manufacturing method of a contact image sensor according to an embodiment of the present invention.

FIG. 9 is a manufacturing process diagram of a stamper used in a manufacturing process of a main part of a manufacturing method of a contact image sensor according to an embodiment of the present invention.

FIG. 10 is a manufacturing process diagram of a stamper used in the manufacturing process of the main part of the manufacturing method of the contact image sensor according to the embodiment of the present invention.

FIG. 11 is a manufacturing process diagram of a stamper used in the manufacturing process of the main part of the manufacturing method of the contact image sensor according to the embodiment of the present invention.

FIG. 12 is a sectional view of a main part of a conventional contact image sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LED line light source 2 Original 3 Rod lens array 4 Light receiving sensor element 5 Substrate 6 Optical waveguide array 7 Optical waveguide 8 Light shielding clad portion 9 Lower clad layer 10 Upper surface clad layer 11 Light receiving sensor element 11a Light receiving window 12 Substrate 13 Circuit part 14 Master metal Mold 15 Form 16 Thermosetting resin 17 Stamper 18 Stamper

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area // B29K 101: 10

Claims (14)

[Claims] 1. A light source for irradiating a document, a plurality of light receiving sensor elements for converting light reflected from the document into an electric signal, and a plurality of optical waveguides for guiding light reflected from the document to the light receiving sensor element are arrayed. The optical waveguide array is divided into the same number of groups as the light-receiving sensor elements, and the light-receiving window on the light-receiving sensor element side is separated from the light-receiving window pitch on the original side for each group. The contact type image sensor is characterized in that the optical waveguide is formed in a tapered shape with a narrower pitch and a gap is provided between each of a plurality of light receiving sensor elements. 2. The contact type image sensor according to claim 1, wherein the optical waveguide array is configured such that a plurality of optical waveguides are applied to each pixel of the light receiving sensor element. 3. The contact type according to claim 1, wherein the optical waveguide array is provided with the pixels at both ends of the light receiving sensor element inside only one optical waveguide of the optical waveguide array. Image sensor. 4. The contact image sensor according to claim 1, wherein a plurality of light receiving sensor elements, an optical waveguide array and a circuit section are formed on the same substrate. 5. A light source for illuminating a document, a plurality of light receiving sensor elements for converting light reflected from the document into an electric signal, and a plurality of optical waveguides for guiding light reflected from the document to the light receiving sensor element are arranged in an array. A contact type image sensor including an optical waveguide array, wherein a plurality of light receiving sensor elements are mounted on a substrate and electrically connected, and then a lower surface clad layer for forming an optical waveguide is formed by a mold resin. A method for manufacturing a contact type image sensor, characterized in that a protective layer for protecting the light receiving sensor element is formed at the same time as forming by a molding method. 6. The method for manufacturing a contact image sensor according to claim 5, wherein an optical waveguide is formed on the lower clad layer by a mold resin molding method. 7. The method of manufacturing a contact image sensor according to claim 5, wherein the stamper for forming the lower clad layer and the optical waveguide is formed of a transparent material. 8. The method for manufacturing a contact image sensor according to claim 7, wherein the transparent substance is a thermosetting resin. 9. The method for manufacturing a contact image sensor according to claim 8, wherein the thermosetting resin is an acrylic resin. 10. The method according to claim 7, wherein the transparent material is soda lime glass. 11. The method of manufacturing a contact image sensor according to claim 7, wherein the transparent substance is an electron beam curable resin. 12. The method for manufacturing a contact image sensor according to claim 11, wherein the electron beam curable resin is a urethane acrylate resin. 13. The method for manufacturing a contact image sensor according to claim 7, wherein the transparent substance is an ultraviolet curable resin. 14. The method for manufacturing a contact image sensor according to claim 13, wherein the ultraviolet curable resin is a urethane acrylate resin.