JP3105795B2 - Complete contact image sensor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a perfect contact type image sensor used as a document reading apparatus such as a facsimile, a copy, and a scanner, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A conventional perfect contact type image sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. H7-111557.
FIG. 6 shows a schematic structural diagram thereof. As a light guide, an optical fiber array 65 formed by aligning a plurality of optical fibers is used.
Is fused between glass substrates using an optical fiber array plate 64 having a structure. Semiconductor image sensor element 6
Reference numeral 1 denotes a light-curing resin 66 attached to one end of an optical fiber array plate 64 such that the light receiving element array 62 faces the optical fiber array 65. A document 68 is placed in close contact with the other end of the optical fiber array plate 64. The illumination light emitted from the light source 67 is obliquely incident, passes through the optical fiber array plate 64, and illuminates the original 68. The light reflected by the original 68 is transmitted to the optical fiber array 65.
And is guided to the light receiving element array 62 to be converted into an image signal.

Further, as disclosed in JP-A-6-291935 , a light source is disposed directly above a semiconductor image sensor element, the light receiving element has at least one light guide port, and the light source emits light. The illumination light to be incident on one surface of the light guide through the light guide opening of the light receiving element, is guided to a document placed in close contact with the other surface of the light guide, and the light reflected by the document is reflected on the other side of the light guide. There has been proposed a high-resolution, low-cost, fully-contact image sensor configured to guide light from one surface to one surface and make the light incident on a light receiving element.

[0004]

However, the above-mentioned prior art has a problem that it lacks long-term reliability. The light receiving element array surface of the semiconductor image sensor element and the light guide are firmly adhered to each other by a photocurable resin, but the photocurable resin contracts when cured. For example, in the case of an ultraviolet (UV) curable resin, the volume shrinkage reaches as high as 8 to 16%. At this time, distortion occurs on the light receiving element array surface due to shrinkage of the photocurable resin, and stress is generated. Further, at the time of reading a document, a compressive force for bringing the light guide into close contact with the document and a stress associated with frictional resistance of the light guide during scanning are transmitted to the light receiving element array surface of the semiconductor image sensor element via the photocurable resin. Therefore, a large amount of stress is repeatedly applied to the light receiving element and the wiring of the semiconductor image sensor element. The stress at this time is not only when the stress exceeds the breaking stress value of the light-receiving element or the wiring material, but even if the stress does not exceed the breaking stress value, the light-receiving element or the wiring causes a fatigue phenomenon due to repeated application. And the destruction of wiring. As a result, the life of the complete contact type image sensor was as low as about 5000 hours in reading time. As described above, the conventional perfect contact type image sensor has a problem that it lacks long-term reliability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a structure of a full contact type image sensor having long-term reliability and a method of manufacturing the same in view of the above-mentioned problems of the prior art.

[0006]

In order to achieve the above object, the present invention provides a semiconductor image sensor having a plurality of light receiving element arrays and one of a plurality of light receiving element arrays provided between the light receiving element arrays and a document to be read. A light guide that guides light incident from the surface to the other surface, and guides optical image information of the document placed in close contact with one surface of the light guide to the other surface of the light guide. In a perfect contact type image sensor that is incident on the light receiving surface of the light receiving element array, the distance between the semiconductor image sensor element and the light guide is 10 μm.
A stress relaxation layer having the above thickness is provided.

[0007] The stress relaxation layer is made of an elastomer or a gel.
A viscoelastic body Le, also preferably has a silicone compound as a main component.

The light guide comprises an optical fiber array formed by aligning an optical fiber composed of a central core, a clad provided on the outer surface of the core, and a light absorbing layer provided on the outer surface of the clad. It is preferable that the optical fiber array plate is an optical fiber array plate sandwiched and fused between glass substrates.

The semiconductor image sensor element comprises a transparent insulating substrate and an array of thin film semiconductor light receiving elements formed on the transparent insulating substrate, and drives the thin film semiconductor light receiving element on the transparent insulating substrate. It is preferable that a thin film semiconductor circuit is formed together.

In this case, the complete contact type image sensor is
A light source is disposed immediately above the semiconductor image sensor element,
The thin-film semiconductor light-receiving element has at least one or more light-guiding ports, and the illumination light emitted by the light source is made incident on the other surface of the light guide through the light-guiding port of the thin-film semiconductor light-receiving element. The light reflected on the surface of the document is guided from one surface of the light guide to the other surface of the light guide, and is incident on the thin film semiconductor light receiving element. It is characterized in that it is configured to be.

According to the present invention, there is provided a semiconductor image sensor having a plurality of light-receiving element arrays and a document which is provided between the light-receiving element array and a document to be read and which is placed in close contact with one surface. A light guide that guides optical image information to the other surface and enters the light receiving surface of the light receiving element array, using an adhesive that acts as a stress relaxation layer,
The method also includes a method of manufacturing a perfect contact type image sensor that is adhered so as to have a thickness of 10 μm or more .

(Function) In the invention described above, the stress caused by resin shrinkage during curing is provided by providing a stress relaxation layer made of a viscoelastic material between the semiconductor image sensor element and the fiber array plate as the light guide. When reading an original, the compressive force caused when the optical fiber array plate is brought into close contact with the original and the stress caused by the frictional resistance of the optical fiber array plate during scanning are not transmitted to the light receiving element array surface of the semiconductor image sensor element. Dissipated inside the relaxation layer. Thereby, the destruction of the light receiving element and the wiring of the semiconductor image sensor element can be suppressed, and as a result, the life of the device becomes 10,000 hours or more, and the long-term reliability of the complete contact image sensor is improved more than ever.

[0013]

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

(First Embodiment) FIG. 1 is a structural view schematically showing a first embodiment of a complete contact image sensor according to the present invention.

FIG. 1 shows a completely close contact type image sensor of this embodiment.
As shown in FIG. 1, a semiconductor image sensor element 11 having a light receiving element array 12 mounted on a printed circuit board 13 is provided. This semiconductor image sensor element 11 has an optical fiber array 15 formed by aligning a plurality of optical fibers.
The light receiving element array 12 is opposed to the optical fiber array 15 via a stress relaxation layer 16 on one surface side of an optical fiber array plate 14 which is a light guide having a structure in which is fused between two glass substrates. Are located in

The stress relieving layer 16 is a viscoelastic material such as an elastomer or a gel , and is obtained by curing a permeable silicone-based adhesive containing a silicone compound as a main component.

Each optical fiber comprises a central core, a clad provided on the outer surface of the core, and a light absorbing layer provided on the outer surface of the clad.

The rest of the configuration is the same as that of the prior art.
8 are placed closely together. A light source 17 for illuminating the original 18 by illuminating the illumination light obliquely toward the optical fiber array plate 14 is arranged, and the light reflected by the original 18 is transmitted to the light receiving element array 12 via the optical fiber array 15. Be guided.

As described above, in the present embodiment, the semiconductor image sensor element 11 and the optical fiber array plate 14 are bonded with a silicone-based adhesive. Therefore, no stress is generated on the light receiving element array surface of the semiconductor image sensor element 11.

In reading the original, the compressive force when the optical fiber array plate 14 is brought into close contact with the original 18 and the stress caused by the frictional resistance of the optical fiber array plate 14 during scanning are dissipated in the stress relaxation layer 16. Therefore, no stress is transmitted to the light receiving element array surface of the semiconductor image sensor element 11.

(Second Embodiment) FIG. 2 is a structural view schematically showing a second embodiment of the complete contact type image sensor of the present invention. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, as shown in FIG. 2 instead of the first embodiment, the light receiving element array 12 of the semiconductor image sensor element 11 is in close contact with a light-transmitting rubber ribbon serving as a stress relaxation layer 29. ing. The semiconductor image sensor element 11 together with the stress relieving layer 29 is adhered to the optical fiber array plate 14 as a light guide by a photo-curable resin (for example, an ultraviolet-curable resin) 26.

In this embodiment, the photocurable resin 2
6 and the stress generated in the optical fiber array plate 24 at the time of scanning by the complete contact type image sensor are dissipated in the stress relaxation layer 29, so that the stress is not transmitted to the light receiving element array surface of the semiconductor image sensor element 11. .

[0024]

Next, an example based on the embodiment of the present invention will be described.

(First Embodiment) FIG. 3 is a structural diagram schematically showing a first embodiment based on the first embodiment of the complete contact type image sensor of the present invention.

Here, the components of the first embodiment based on the complete contact type image sensor in the first embodiment will be specifically described, and the manufacturing method thereof will be described.

First, as shown in FIG. 3, a thin film light receiving element 33 of an amorphous silicon thin film diode and a polysilicon thin film transistor for driving the thin film light receiving element 33 on a non-alkali glass substrate 31 which is a transparent insulating substrate by using a normal thin film process. And a thin film drive circuit 32 formed in a one-dimensional array, thereby producing a semiconductor image sensor element indicated by reference numeral 11 in FIG.

Next, after the semiconductor image sensor element as described above is mounted on the printed circuit board 34, the light receiving element array surface and one surface of the optical fiber array plate 35 are adhered by an adhesive which becomes the stress relaxation layer 37 after curing. .

The optical fiber array plate 35 has a one-dimensional array of a plurality of optical fibers having a numerical aperture of 0.9 and a depth of focus of 70 μm.
Is used.

The adhesive which becomes the stress relaxation layer 37 after curing is an elastomer type silicone adhesive, and the curing condition is left at 25 ° C. for 72 hours. The thickness of the stress relaxation layer 37 was set to 10 μm so as to be within the depth of focus of the optical fiber array 36.

Finally, a light source 38 using an LED array was provided, and a complete contact type image sensor was manufactured.

The complete contact type image sensor manufactured as described above has the stress relaxation layer 37 between the light receiving element array surface of the semiconductor image sensor element and one surface of the optical fiber array plate 35. Fatigue fracture was suppressed, and long-term reliability was improved.

(Second Embodiment) FIG. 4 is a structural diagram schematically showing a second embodiment based on the first embodiment of the complete contact type image sensor of the present invention.

Here, the components of the second embodiment based on the complete contact type image sensor in the first embodiment will be specifically described, and the manufacturing method thereof will be described.

First, as shown in FIG. 4, on a non-alkali glass substrate 41, at least one or more slit-shaped light guide ports (not shown) made of an amorphous silicon thin film diode are formed by a normal thin film process. A thin film light receiving element 43 and a thin film driving circuit 42 of a polysilicon thin film transistor for driving the thin film light receiving element 43 were formed in a one-dimensional array to produce a semiconductor image sensor.

Next, after mounting the semiconductor image sensor element as described above on the printed circuit board 44, one surface of an optical fiber array plate 45 using an optical fiber array 46 having a numerical aperture of 0.9 and light reception of the semiconductor image sensor element are performed. The element array surface was bonded with an adhesive that became a stress relaxation layer 47 after curing.

The adhesive that becomes the stress relaxation layer 47 after curing is a gel-type two-component mixed silicone adhesive, and the thickness of the stress relaxation layer 47 is 10 μm.

Finally, the light source 48 of the LED array is connected to the thin film light receiving element 43 having a slit-like light guide port (not shown).
And a complete contact type image sensor was fabricated.

The complete contact type image sensor manufactured as described above uses the illumination light from the light source 48 disposed immediately above the semiconductor image sensor element to transmit the illumination light from at least one light guide port of at least one light receiving element of the semiconductor image sensor element. The light reflected from the surface of the document 49 is guided to the light receiving element of the semiconductor image sensor device by the optical fiber array 46.

The stress relief layer 47 is provided between the light receiving element array surface of the semiconductor image sensor element and one surface of the optical fiber array plate 45.
Therefore, fatigue destruction of light receiving elements and wiring is suppressed,
Long-term reliability has improved.

(Third Embodiment) FIG. 5 is a sectional view for explaining a third embodiment based on the second embodiment of the complete contact type image sensor of the present invention.

Here, the components of the third embodiment based on the complete contact type image sensor in the second embodiment will be specifically described, and the manufacturing method thereof will be described.

First, in FIG. 5, a thin film light receiving element 53 and a thin film driving circuit 52 for driving the thin film light receiving element 53 are formed in a one-dimensional array on a non-alkali glass substrate 51 as in the first embodiment. Produced.

Next, such a semiconductor image sensor element is disposed in a pair of molds 55 and 56, and a liquid silicone rubber 54 is injection-molded on the light receiving element array surface of the semiconductor image sensor element to reduce stress. Layer thickness 10μ
m.

The injection molding temperature and curing time are 150 ° C. and 5 minutes, and the injection molding is completed within a temperature and time range that does not affect the semiconductor image sensor element. Further, since the light receiving element surface of the semiconductor image sensor element is covered with the liquid silicone rubber 54, no compressive stress is applied to the light receiving element surface of the semiconductor image sensor element.

Next, after mounting the above-described semiconductor image sensor element with the stress relaxation layer on a printed circuit board, the optical fiber array plate and the light receiving element array surface of the semiconductor image sensor element are sandwiched by the stress relaxation layer. And bonded with a photocurable resin (for example, an ultraviolet curable resin). The thickness of the ultraviolet curable resin was 6 μm.

Finally, a light source is provided similarly to the first embodiment.
A complete contact image sensor was manufactured.

Since the complete contact type image sensor thus manufactured has a stress relaxation layer on the light receiving element array surface of the semiconductor image sensor element, fatigue damage of the light receiving element and wiring is suppressed, and long-term reliability is improved.

(Fourth Embodiment) Here, the components of the fourth embodiment based on the complete contact type image sensor according to the second embodiment will be specifically described, and a manufacturing method thereof will be described.

In the same manner as in the first embodiment, a thin film light receiving element array and a thin film driving circuit for driving the same were formed on an alkali-free glass substrate to produce a semiconductor image sensor. Then, after mounting the semiconductor image sensor element on a printed circuit board, a 10 μm thick silicone rubber is brought into close contact with the light receiving element array surface of the semiconductor image sensor element,
A stress relaxation layer was formed. At this time, to prevent air from entering between the semiconductor image sensor element and the silicone rubber,
It is preferable to press the silicone rubber against the semiconductor image sensor element while applying a slight tension to the silicone rubber. Due to the viscosity of the silicone rubber surface and the applied tension, the silicone rubber does not peel off from the semiconductor image sensor element without applying a new special force.

Next, the optical fiber array plate and the light receiving element array surface of the semiconductor image sensor were bonded with a photocurable resin (for example, an ultraviolet curable resin) so as to sandwich the stress relaxation layer.

Finally, a light source is provided in the same manner as in the first embodiment.
A complete contact image sensor was manufactured.

Since the complete contact type image sensor thus manufactured has a stress relaxation layer on the light receiving element array surface of the semiconductor image sensor element, fatigue damage of the light receiving element and wiring is suppressed, and long-term reliability is improved.

In the above embodiment, the semiconductor image sensor element having the thin film drive circuit and the thin film light receiving element array on the alkali-free glass substrate is used, but other transparent insulating substrates such as a quartz substrate and a plastic substrate are used. A semiconductor image sensor device having a thin-film drive circuit and a thin-film light-receiving element array on top, and a charge-coupled device (CCD) on a silicon substrate
Similar effects were obtained by using another semiconductor image sensor element such as a semiconductor image sensor element having an array. Further, although the optical fiber array plate is used as the light guide, similar effects can be obtained by using other light guides such as optical fibers and thin glass which are not arranged in an array.

[0055]

As described above, the present invention provides a semiconductor image sensor having a plurality of light receiving element arrays,
A light guide provided between the light receiving element array and the document to be read, and guiding light incident from one surface to the other surface, the light guide of the document placed in close contact with one surface of the light guide. In a complete contact type image sensor in which optical image information is guided to the other surface of the light guide and is incident on a light receiving surface of the light receiving element array, a stress relaxation layer is provided between the semiconductor image sensor element and the light guide. In this way, the destruction of the light receiving element and the wiring of the semiconductor image sensor element is suppressed, and as a result, the device life is increased from about 5000 hours to 10,000 hours or more, and the long-term reliability is improved.

[Brief description of the drawings]

FIG. 1 is a structural diagram schematically showing a first embodiment of a complete contact image sensor according to the present invention.

FIG. 2 is a structural diagram schematically illustrating a second embodiment of the complete contact image sensor according to the present invention.

FIG. 3 is a structural view schematically showing a first example based on the first embodiment of the complete contact type image sensor of the present invention.

FIG. 4 is a structural view schematically showing a second example based on the first embodiment of the complete contact image sensor of the present invention.

FIG. 5 is a cross-sectional view for explaining a third example based on the second embodiment of the complete contact image sensor of the present invention.

FIG. 6 is a structural diagram schematically showing a conventional complete contact image sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Semiconductor image sensor element 12 Light receiving element array 13, 34, 44 Printed circuit board 14, 35, 45 Optical fiber array plate 15, 36, 46 Optical fiber array 16, 29, 37 Stress relaxation layer 17, 38, 48 Light source 18, 39 , 49 Document 26 Photo-curable resin 31, 41, 51 Alkali-free glass substrate 32, 42, 52 Thin film drive circuit 33, 43, 53 Thin film light receiving element 54 Liquid silicone rubber 55, 56 Mold

Claims (7)

(57) [Claims] 1. A semiconductor image sensor device having a plurality of light receiving element arrays, and a light guide provided between the light receiving element array and a document to be read, for guiding light incident from one surface to the other surface. A perfect contact image in which optical image information of the document placed in close contact with one surface of the light guide is guided to the other surface of the light guide and is incident on the light receiving surface of the light receiving element array. in the sensor, between the light guide and the semiconductor image sensor element
Complete contact type image sensor, wherein a stress relaxation layer is disposed. 2. The method according to claim 1, wherein the stress relaxation layer is an elastomer or
2. The perfect contact type image sensor according to claim 1, wherein the image sensor is a viscoelastic body of gel . 3. The perfect contact type image sensor according to claim 1, wherein the stress relaxation layer contains a silicone compound as a main component. 4. An optical fiber formed by aligning an optical fiber composed of a central core, a cladding provided on an outer surface of the core, and a light absorbing layer provided on an outer surface of the cladding. The image sensor according to claim 1, wherein the image sensor is an optical fiber array plate in which the array is sandwiched and fused between glass substrates. 5. The semiconductor image sensor device comprises a transparent insulating substrate and an array of thin-film semiconductor light-receiving devices formed on the transparent insulating substrate. The thin-film semiconductor light-receiving device is provided on the transparent insulating substrate. 2. The complete contact type image sensor according to claim 1, wherein a driving thin film semiconductor circuit is also formed. 6. The complete contact type image sensor according to claim 5, wherein a light source is disposed immediately above the semiconductor image sensor element, wherein the thin-film semiconductor light receiving element has at least one light guide port, The illumination light emitted by the light source is made incident on the other surface of the light guide through the light guide opening of the thin film semiconductor light receiving element, and is guided to the surface of the document sent into one surface of the light guide, and A completely-contact image sensor, wherein light reflected by a surface is guided from one surface of the light guide to the other surface of the light guide and is incident on the thin-film semiconductor light receiving element. 7. An optical system for a document which is provided between a semiconductor image sensor device having a plurality of light receiving element arrays and a document to be read and which is placed in close contact with one surface. A method for manufacturing a complete contact type image sensor, wherein an image guide for guiding image information to the other surface and incident on the light receiving surface of the light receiving element array is bonded using an adhesive acting as a stress relaxation layer.