JPH0851513A - Perfect contact image sensor unit - Google Patents

Abstract

(57) [Summary] [Construction] The circuit conductor layer 44 is formed on the surface of an opaque glass substrate 48 having an optical fiber array 46 having a transparent glass plate 47 and an optical fiber array 46 formed by arranging a large number of optical fibers having a light absorber layer on the outer surface. Face-down bonding of the image sensor chip 41 on the transparent photo-curable insulating resin 45. At this time, the light receiving element array 42 is mounted so as to correspond to the optical fiber array 46. A light shielding layer 52 is formed on the end of the transparent glass plate 47 on the side of the original contact surface, a light collecting rod 49 is formed on the side of the light receiving element, and a linear illumination light source 50 is arranged so as to be in close proximity thereto. The original 51 is illuminated through the plate 47 and the optical fiber array 46. The optical information from the original 51 is guided to the light receiving element array 42 through the optical fiber array 46 without light crossing. [Effects] Completely compact, lightweight, and low-cost realization of a perfect contact image sensor unit capable of high-quality, high-resolution reading with no flare light or crosstalk of light and small sensitivity variations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perfect contact type image sensor unit for converting an optical image into an electric signal.

[0002]

2. Description of the Related Art As shown in FIG. 2, a complete contact type image sensor unit using a conventional optical fiber array is mounted such that a light receiving element array 62 formed on a semiconductor image sensor element 61 is in contact with the optical sensor array. Fiber array 63
The original 64 placed closely on the other end of the
This is verified by the D array 65, and the optical information is guided to the light receiving element array 62 using the optical fiber array 63 and converted into an image signal.

[0003]

However, in the image sensor unit as described above, since the LED array 45 is used as the light source, the illuminance of the document surface greatly varies,
The sensitivity variation of the sensor was increased, and the image reading performance was degraded. In addition, from the document 44 to the LED array 45
Up to a certain distance, the size of the unit itself becomes large, and a large number of LED chips are used, which causes a cost increase.

[0004]

In order to solve the above problems, an image sensor unit according to the present invention comprises a light guide body made of a translucent material as a light source, and a diffuser and light emission provided on a part of the surface. This is a structure in which a linear illumination light source composed of elements is used, and this is optically connected directly to a transparent glass plate which is a slit for taking in illumination light, or is connected through a rod lens.

[0005]

According to the present invention having the above-mentioned structure, the surface of the original is uniformly illuminated by the linear illumination light source close to the original, and optical information from the original is crossed (crosstalk) and unnecessary by the optical fiber array. By guiding the light to the light receiving element array without optical information (flare light), high quality and high resolution image reading can be realized, and the image sensor unit itself can be made smaller and lighter and the cost can be reduced. .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image sensor according to an embodiment of the present invention will be described below with reference to the drawings.

1A and 1B are a sectional view and a plan view of an optical fiber array plate of a perfect contact type image sensor according to an embodiment of the present invention, respectively. 1 is an optical fiber array for guiding optical information from a document, 2 is a light absorber layer provided at a specific pitch in the first optical fiber array, and 3 is closely attached to the side surface of the first optical fiber array. The transparent glass plates 8 and 8 are two opaque glass substrates sandwiching the optical fiber array 1 and the transparent glass plate 3.

FIG. 2 is a block diagram of an optical fiber forming an optical fiber array. 11 is a core, 12 is a clad formed on the outer surface of the core 11, 13 is a clad 12
Is a light absorber layer formed on the outer surface of the.

3A and 3B are a schematic view and a sectional view of a linear illumination light source, respectively. Reference numeral 21 is an LED lamp as a light source, 22 is a light guide body that linearly guides the light from the light source 21 onto the original, and 23 is light that is emitted from the light source 21 and that has passed through the light guide body 22 is diffused in the emission direction. It is a light diffusion layer for emitting.

4A and 4B are a schematic view and a sectional view of the daylighting rod, respectively. Lighting rod 3
1 plays a role of condensing the light from the linear illumination light source to some extent only in the sub-scanning direction and guiding it to the transparent glass plate (slit) of the optical fiber array plate.

FIG. 5 is a front sectional view of the perfect contact type image sensor unit in the embodiment of the present invention. 41 is an image sensor chip, 42 is an image sensor chip 41
, 43 is an electrode array provided on the surface of the image sensor chip 41, 44 is a circuit conductor layer formed on the surface of the opaque glass substrate 48,
Reference numeral 46 is an optical fiber array arranged so as to correspond to the light receiving element array 42, and 47 is a first optical fiber array 46.
Transparent glass plate, which is placed so as to be in close contact with the side surface of the
Is two opaque glass substrates sandwiching the optical fiber array 46 and the transparent glass plate 47, 45 is an opaque glass substrate 48 and a transparent photocurable insulating resin for mounting the image sensor chip 41 on the optical fiber array 46, 49 Is a light-collecting rod formed on the light-receiving element array side of the transparent glass plate 47, 50 is a linear illumination light source arranged in the vicinity of the light-collecting rod 49, 51 is an original to be read, and 52 is the original contact surface side of the transparent glass plate 47. A light-shielding layer 53 provided in the above is an opaque sealing resin that seals and shields one side surface (the side where the image sensor chip is located) of the image sensor chip 41 and the daylighting rod 49.

Next, the details of the perfect contact type image sensor unit constructed as described above will be described in detail.

First, a light receiving element array 42 such as a phototransistor or a photodiode and a CCD or MO are formed on a single crystal silicon substrate (wafer) by using a semiconductor process.
An access circuit (not shown) such as an S or bipolar IC is provided. Each electrode 43 has a structure in which Au wire bumps are formed on the Al electrode by a wire bonder. Thereafter, this wafer is cut by a high-precision dicing technique to make a semiconductor image sensor chip 41.

Next, the optical absorber layer 1 having a thickness of 2 to 3 μm is formed on the outer surface of the clad 12 of the optical fiber having a diameter of about 20 μm.
3 is formed, and a number of these optical fibers are arranged in parallel in a strip shape to prepare an optical fiber array 1 (46), and a transparent glass plate 3 (47) is attached so as to be in close contact with this side surface, and is composed of two pieces of glass. The optical fiber array plate is produced by sandwiching it between the opaque glass substrates 48 and applying heat from both sides while applying heat of about the glass melting point. Next, the circuit conductor layer 44 is formed on the one end surface of the opaque glass substrate 48 by using a noble metal such as Au or Ag-Pt and sticking a flexible printed circuit board by screen printing. Further, a black resin is applied to the other end (original contact surface side) of the transparent glass plate 3 (47) by a screen printing method to shield the light-shielding layer 5.
Form 2 Next, in the image sensor chip 41 manufactured previously, the light receiving element array 42 is used as the optical fiber array 1.
It is mounted so that the electrode 43 is connected to a predetermined position of the circuit conductor layer 44 by face-down bonding through an acrylate-based transparent photocurable insulating resin 45 so as to be in close contact with (46). In this way, a perfect contact image sensor can be obtained.

On the other hand, regarding the linear illumination light source 50,
The light guide 21 is made of acrylic or polycarbonate by injection molding. The light guide has a truncated cone shape as shown in FIG. 3, and the diameter of its cross section is reduced as it goes from the end face to the center. Next, the LED element is molded with a transparent resin to produce the LED lamp 22, and the LED lamp 22 is placed in close contact with both end surfaces of the light guide 21. In addition, the lighting rod 31
(49) is made of acrylic or polycarbonate by extrusion molding.

Here, the daylighting rod 31 (4) is formed on the surface of the transparent glass plate 47 of the above-mentioned perfect contact type image sensor.
9) is mounted by optical matching with a transparent resin having a refractive index (n = 1.5 to 1.6) similar to those of the daylighting rod 31 (49) and the transparent glass plate 47. Further, a line-shaped illumination light source 50 is arranged in the vicinity of and above the daylighting rod 31 (49) so that the illumination light is emitted to the document by about 4 times.
The light is incident at 0 ° (about 25 ° in the medium such as the light guide, the daylighting rod, and the fiber array plate).

The operation principle and characteristics of the perfect contact type image sensor unit thus manufactured will be described below.

The illumination light emitted from the linear illumination light source 50 is
The document 51 is narrowed down in the sub-scanning direction through the lighting rod 49, and further traverses the transparent glass plate 47 and the optical fiber array 46 to illuminate the document 51. At this time, the optical fiber array 1 (4
Regarding the light absorber layer 13 of the optical fiber constituting 6), the light transmittance is set to about 20% so that light can pass to some extent.

At this time, the opaque glass substrate 48 and the light shielding layer 31
Since the opaque sealing resin 53 and the like exist, it is possible to erase the light (flare light) directly entering the light receiving element array 42 without the light from the linear illumination light source 50 reaching the original 51.

Optical information from the document 51 is guided to the light receiving element array 42 by the optical fiber array 1 (46) in a one-to-one correspondence without crossing of light (crosstalk).

As a result, when an 8 dot / mm light receiving element array was used, the MTF value was 65% at 4 lp / mm, and the sensitivity variation of the sensor was 25% in the conventional case (using an LED array as the light source). Was reduced to 15%, and a perfect contact image sensor unit capable of high-performance reading was realized. Further, the distance between the linear illumination light source 50 and the document surface can be reduced from the conventional 10 mm to 1.5 mm,
The sensor unit is about half the size
It was possible to reduce the weight. Further, in the LED array which is the conventional light source, a light emitting element (LED) is used to illuminate an A4 size document.
However, in the present invention, 4 to 32 elements are required.
We were able to reduce the cost to 8 elements and realize cost reduction.

[0022]

As described above, according to the present invention, it is possible to reduce the sensitivity variation of the sensor, and at a low cost, an ultra-compact and lightweight perfect contact type image sensor unit capable of reading an image with high quality and high resolution. Can be realized.

[Brief description of drawings]

FIG. 1 is a side sectional view and a plan view of an optical fiber array plate according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an optical fiber according to an embodiment of the present invention.

FIG. 3 is a schematic view and a sectional view of a linear illumination light source according to an embodiment of the present invention.

FIG. 4 is a schematic view of a daylighting rod according to an embodiment of the present invention.

FIG. 5 is a front sectional view of a perfect contact type image sensor unit according to the embodiment of the invention.

FIG. 6 is a front sectional view and a side sectional view of a conventional image sensor unit.

[Explanation of symbols]

 1 Optical Fiber Array 2 Light Absorber Layer 3 Transparent Glass Plate 8 Opaque Glass Substrate 11 Core 12 Clad 13 Light Absorber Layer 21 Light Guide 22 LED Lamp 23 Light Diffusing Layer 31 Daylighting Rod 41 Image Sensor Chip 42 Photoreceptor Array 43 Electrode 44 Circuit Conductor Layer 45 Transparent Light Curing Insulation Resin 46 Optical Fiber Array 47 Transparent Glass Plate 48 Opaque Glass Substrate 49 Daylighting Rod 50 Linear Illumination Light Source 51 Original 52 Light-Shielding Layer 53 Opaque Sealing Resin

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroki Hongo 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (20)

[Claims] 1. An optical fiber array formed by arranging a plurality of optical fibers, and a plurality of light receiving element arrays provided on one end side of the optical fiber array, the optical fiber array being in close contact with a side surface of the optical fiber array. A transparent plate (slit for lighting) is arranged, and the optical fiber array and the transparent plate are sandwiched by two opaque substrates from both sides, and a light emitter is provided on one end side (light receiving element array side) of the transparent plate and the other end side. In a perfect contact type image sensor unit characterized in that a light-shielding layer is provided on the (original contact surface side), a light guide made of a translucent material as the light emitter, and a light provided on part of the light guide surface A complete contact type image sensor unit characterized by using a linear illumination light source having a diffusion layer and a light emitting element. 2. The perfect adhesion type optical fiber according to claim 1, wherein the optical fiber is composed of a core at the center, a clad provided on the outer surface of the core, and a light absorber layer provided on the outer surface of the clad. Image sensor unit. 3. A light-emitting body is provided on one end side (light-receiving element array side) of a transparent plate (light-collecting slit) via a light-collecting rod made of a translucent material having a lens function only in the sub-scanning direction. The perfect contact type image sensor unit according to claim 1. 4. The light guide of the linear illumination light source has a cross-sectional shape that is similar in shape from both end faces toward the central portion and gradually decreases to a minimum shape at the central portion, and light emitting elements are provided on both end faces thereof. The perfect contact type image sensor unit according to claim 1, wherein a diffusion layer is provided in a straight line from one end surface to the other end surface on the side surface thereof. 5. The perfect contact image sensor unit according to claim 4, wherein the width of the diffusion layer is proportional to the size of the cross-sectional shape of the light guide. 6. The perfect contact type image sensor unit according to claim 4, wherein the width of the diffusion layer is constant. 7. The light guide has a straight line connecting the same points on both end faces on the side surface of the light guide and perpendicular to the both end faces. 5. A diffusion layer is provided on the side surface of the optical body, and the light emission side is opposed to a transparent plate (lighting slit).
The complete contact type image sensor unit described. 8. The perfect contact type image sensor unit according to claim 4, wherein the light guide has a circular cross-sectional shape. 9. The light guide of the linear illumination light source has the same cross-sectional shape (columnar shape) from one end face to the other end face, and light emitting elements are provided on both end faces thereof, and one side face to the other end face is provided on the side face thereof. The perfect contact type image sensor unit according to claim 1, wherein a diffusion layer is provided in a straight line. 10. The perfect contact type image sensor unit according to claim 9, wherein the width of the diffusion layer increases from the end face toward the central portion and becomes maximum at the central portion. 11. The perfect contact type image sensor unit according to claim 9, wherein the width of the diffusion layer is constant. 12. The perfect contact image sensor according to claim 9, wherein the light guide has a circular cross-sectional shape. 13. The refractive index of the light guide of the linear illumination light source is
2. The perfect contact type image sensor according to claim 1, wherein the refractive index of the transparent plate (slit for lighting) is approximately the same as that of the transparent plate. 14. The perfect contact type image sensor according to claim 1, wherein the light guide of the linear illumination light source and the transparent plate (slit for lighting) are made of the same material. 15. When the line-shaped illumination light source is installed on a transparent plate (lighting slit), the light guide of the line-shaped illumination light source and the transparent plate (lighting slit) have approximately the same refractive index. 2. The perfect contact type image sensor according to claim 1, wherein the light guide body and the transparent plate (slit for light collection) are connected by direct optical matching using a transparent resin. 16. The perfect contact type image sensor according to claim 3, wherein the light-reflecting rod has a refractive index substantially equal to that of the transparent plate (light-collecting slit). 17. The perfect contact image sensor according to claim 3, wherein the lighting rod and the transparent plate (lighting slit) are made of the same material. 18. When the lighting rod is installed on a transparent plate (lighting slit), a transparent resin having a refractive index approximately equal to that of the lighting rod and the transparent plate (lighting slit) is used. 4. The perfect contact type image sensor according to claim 3, wherein the lighting rod and the transparent plate (lighting slit) are connected by direct optical matching. 19. A light emitting diode (LED) as a light emitter.
The perfect contact type image sensor unit according to claim 1, wherein: 20. The illumination light from the linear illumination light source is 0 ° to.
The perfect contact type image sensor unit according to claim 1, wherein the original is illuminated within a range of 50 °.