JPH0567016U - Image sensor - Google Patents

Abstract

(57) [Summary] [Object] To provide an image sensor having a simpler structure while maintaining a structure in which the width of the sensor substrate in the sub-scanning direction can be made as narrow as possible. [Structure] Sensor substrate 1 on which photoelectric conversion element 20 is formed
2 to the circuit board 14 on which the ICs 24a and 26 are mounted.
A support member 18 having the same thickness as that of the sensor substrate 12 is disposed adjacent to the sensor substrate 12, and the sensor substrate 12 is provided over the sensor substrate 12 and the support member 18.
A cover glass 16 having a width wider than the width D in the sub-scanning direction is arranged. Further, a light shielding film is provided on the sensor substrate 12 mounting portion on the circuit substrate 14 so that excess light does not enter the photoelectric conversion element 20.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an image sensor used in a document reading unit such as a facsimile, an image scanner, a digital copying machine, and an electronic blackboard, and more particularly to a perfect contact type image sensor that does not require a lens system.

[0002]

[Prior Art]

 Conventionally, various proposals have been made regarding the form of a complete contact type image sensor, but the present inventors have already proposed an image sensor 2 using a wide cover glass 1 as shown in FIG. 5 ( (Application No. 3-52297).

The image sensor 2 includes a sensor substrate 3 in which a large number of photoelectric conversion elements 3 a are arranged in a line, a COG (Chip on Glass) substrate 4 in which a signal processing IC 4 a and the like are mounted, and these. It is composed of a supporting glass 5 for supporting and fixing, and a cover glass 1 which is attached so as to straddle the sensor substrate 3 and the COG substrate 4. The image sensor 2 is attached to a frame 7 together with a printed circuit board 6 on which an LED array 6a, a driving IC 6b, a connector 6c, etc. are mounted, and is used as an image sensor unit 8.

In this image sensor 2, since the wide cover glass 1 ensures a sufficient width for smoothly conveying the original, the width of the sensor substrate 3 in the sub-scanning direction is as narrow as possible. Therefore, the manufacturing cost of the image sensor 2 can be significantly reduced.

[0005]

[Problems to be solved by the device]

 However, this image sensor 2 has a four-layer three-layer structure including the sensor substrate 3, the COG substrate 4, the supporting glass 5, and the cover glass 1, so that the alignment in the laminating (bonding) process is complicated. was there. Further, since a large supporting glass 5 is used and the ICs 4a and 6b are separately mounted on the printed circuit board 6 and the COG substrate 4, there is a problem that the cost is complicated and the cost is high.

Therefore, the inventors of the present invention provide an image sensor of low cost and high performance while maintaining a structure in which the width of the sensor substrate in the sub-scanning direction can be made as narrow as possible. As a result of intensive studies, the present invention has been achieved.

[0007]

[Means for Solving the Problems]

 The gist of the image sensor according to the present invention is to provide an image sensor including a sensor substrate on which a plurality of photoelectric conversion elements are arranged in parallel, and a circuit substrate for operating the sensor substrate. A light-transmissive thin plate that is arranged on the circuit board and has a support member having the same thickness as the sensor board adjacent to the sensor board and wider than the width of the sensor board in the sub-scanning direction. Is disposed across the sensor substrate and the supporting member.

Further, in the image sensor, an original that is conveyed on the light-transmissive thin plate on the surface of either or both of the circuit board and the sensor board is transferred from the circuit board side. This is because a light-shielding film was provided in a portion other than the light guide path for illuminating.

[0009]

[Action]

 According to such an image sensor, since the supporting member is arranged adjacent to the sensor substrate and the wide light-transmitting thin plate is arranged so as to extend over these, the document is placed on the light-transmitting thin plate. It will be transported smoothly. That is, the translucent thin plate secures a width sufficient to smoothly convey the original. Therefore, the width of the sensor substrate in the sub-scanning direction can be made as narrow as possible, and the manufacturing cost of such an image sensor can be significantly reduced. Further, since the sensor board is arranged on the circuit board, the sensor board is supported and fixed by the circuit board. That is, this circuit board has both the role of operating the sensor board and the role of supporting and fixing the sensor board. This simplifies alignment in the stacking process and further reduces manufacturing costs.

Further, the document is illuminated from the circuit board side through the light guide path, but since a light shielding film is provided in a portion other than the light guide path, extra light is transmitted through the sensor board and the like. There is no such thing. Therefore, light other than the reflected light from the document does not enter the photoelectric conversion element, and the reading accuracy is improved. The position where the light-shielding film is provided may be on the surface of the circuit board, on the surface of the sensor board, or on the surfaces of both the circuit board and the sensor board, as long as it is a part other than the light guide path. It may be.

[0011]

【Example】

 Next, an embodiment of the image sensor according to the present invention will be described in detail with reference to the drawings.

1 and 2, reference numeral 10 is an embodiment of the image sensor according to the present invention. The image sensor 10 includes a sensor substrate 12 for reading a document, a circuit substrate 14 for operating the sensor substrate 12, a cover glass (translucent thin plate) 16 for protecting the sensor substrate 12, and a cover glass. And a supporting member 18 for supporting 16.

The sensor substrate 12 is made of glass, and a large number of photoelectric conversion elements 20 made of thin film semiconductors such as amorphous silicon a-Si and Cd S -Cd Se are linearly formed on the sensor substrate 12. Although not shown, drive wirings for applying a drive voltage to these photoelectric conversion elements 20 and signal wirings for leading out signals from the photoelectric conversion elements 20 are also formed. A light guide window (not shown) is formed in the vicinity of the photoelectric conversion elements 20 in order to illuminate a document conveyed on the cover glass 16 by a light source arranged on the circuit board 14 side.

The sensor board 12 is attached to a predetermined position on the circuit board 14 with an adhesive or the like. The circuit board 14 is also made of glass, and a wiring pattern (not shown) is formed on the circuit board 14, and driving ICs 24a and 24b for driving the photoelectric conversion element 20 and a signal for processing a signal from the photoelectric conversion element 20. The processing IC 26 is mounted. That is, the circuit board 14 is a COG (Chip on Glass). The driving ICs 24a, 24b are arranged at two locations near both ends of the sensor board 12, and the terminals of these three ICs 24a, 24b, 26 are connected to the wirings formed on the sensor board 12. It is directly connected to the output terminal by wire bonding. The wiring pattern is formed of a thin film of chromium Cr, aluminum Al, or a thick film of gold Au, silver Ag, copper Cu, or the like. Further, a light-shielding film 28 is provided in the portion of the circuit board 14 on which the sensor substrate 12 is mounted, the light-shielding film 28 having a slit-shaped opening only in the portion serving as the light guide path. Here, the light guide path is a traveling path of light for illuminating a document conveyed on the cover glass 16 from the circuit board 14 side. The light shielding film 28 is preferably formed at the same time as the wiring pattern or the like.

The support member 18 is also made of glass and has the same thickness as the sensor substrate 12. The support member 18 is disposed adjacent to the sensor substrate 12, and is attached on the circuit board 14 with an adhesive or the like. Further, a cover glass 16 wider than the width D of the sensor substrate 12 in the sub-scanning direction is attached across the sensor substrate 12 and the supporting member 18 with an adhesive or the like. The cover glass 16 has a thickness of 100 μm or less, preferably 50 μm. The adhesive for adhering the sensor substrate 12, the support member 18, and the cover glass 16 is mainly a thermosetting type epoxy resin type adhesive, but it may be a UV curing type. It may be a silicone resin type.

The image sensor 10 is attached to a resin frame 30 as shown in FIG. 3 and used as an image sensor unit 32. A connector 34 is embedded in the frame 30, and a printed circuit board 38 having a light source 36 such as an LED array or a xenon lamp is provided. The connector 34 is used to input a power supply or control signal from the outside and output an image signal or the like from the inside, and the circuit board 14 is connected to the connector 34 via a flexible wiring 40. Further, a cover 42 made of stainless steel is attached in order to smoothly send the document 41 onto the sensor substrate 12. Although the connector 34 can be directly mounted on the circuit board 14, it is embedded in the frame 30 in consideration of reliability and the like. The frame 30 may be formed by cutting, drawing, or die-casting a metal material such as aluminum or zinc.

According to the image sensor unit 32, the document 41 is sequentially conveyed while being pressed against the cover glass 16 by the platen roller 43. Further, the original 41 is illuminated by the light emitted from the light source 36 and transmitted through the circuit board 14 and the sensor board 12. Then, the reflected light corresponding to the shading of the original 41 enters the photoelectric conversion element 20 and the original 41 is read.

As described above, in the image sensor 10 according to the present invention, the cover glass 16 secures a width sufficient to smoothly convey the document 41, for example, a width of 6 mm or more. The width D in the direction can be made as narrow as possible, for example, to about 2 to 4 mm which is 6 mm or less. Therefore, a large number of sensor substrates 12 can be manufactured at one time, and the manufacturing cost can be significantly reduced. However, since the circuit board 14 itself is also used as the supporting glass 5 in the conventional image sensor 2 and the sensor substrate 12 and the supporting member 18 are adhered on the circuit board 14, the glass substrate is more difficult than the conventional image sensor 2. The sticking area of has decreased. Therefore, the work of attaching glass or the like becomes very simple, and the amount of glass used is reduced as a whole, so that the material cost is reduced.

Further, since the light-shielding film 28 is provided to prevent excess light from passing through the sensor substrate 12 and the like, the reading accuracy is high. Moreover, since it is not necessary to provide a light guiding slit or the like on the frame 30, the structure is extremely simple, and the image sensor unit 32 as a whole is significantly downsized. Further, since the frame 30 is also made of resin, the cost is greatly reduced.

Further, the height of the ICs 24a, 24b, 26, etc. is lower than before, and even when coated with a protective resin or the like, it does not protrude above the cover glass 16 and is very easy to handle in actual use. Is. Further, not only the signal processing IC 26 but also the driving ICs 24a and 24b are mounted on the circuit board 14, and all the circuits are concentrated on the circuit board 14. Therefore, the structure is extremely simple. In addition, since one driving IC is usually mounted separately in two, the width occupied by the driving wiring on the sensor substrate 12 is about half.

Further, since the sensor substrate 12, the circuit substrate 14, the cover glass 16 and the supporting member 18 are made of glass having substantially the same coefficient of thermal expansion, warpage or peeling may occur due to temperature change. It's also excellent in reliability.

The embodiment of the image sensor according to the present invention has been described above in detail, but the present invention is not limited to the above-described embodiment, and can be implemented in other modes.

For example, in the above-described embodiment, the light shielding film 28 is provided on one surface of the circuit board 14, but it may be provided on both surfaces. Further, it may be provided only on the back side of the sensor board 12, or may be provided on both the circuit board 14 and the sensor board 12. That is, it is preferable that the light-shielding film is provided on the entire surface as much as possible so that excess light does not enter the photoelectric conversion element 20, and it may be provided anywhere other than the portion serving as the light guide path. Further, it is also possible to use a conventional frame with a slit without providing a light shielding film.

Further, the circuit board does not have to be transparent glass, and may be a circuit board 46 using a printed board having an oval slit 44 as shown in FIG. 4, for example. The slit 44 is for illuminating the original from the back side of the sensor substrate 12. It is preferable to use a hard printed circuit board made of glass epoxy, ceramic, metal or the like. In addition, a suitable reinforcing material or the like may be installed so that the circuit board 46 is not bent by the pressure of the platen roller.

Further, only one of the signal processing IC and the driving IC may be mounted on the circuit board, and the remaining ICs may be mounted on the printed board 38 on which the light source 36 is mounted. .. Further, one or three or more driving ICs may be mounted, and usually one or more signal processing ICs may be mounted.

Further, the supporting member may be not particularly glass but may be resin or metal, and the material thereof is not limited at all. However, when metal is used, it is necessary to provide an appropriate insulating coat so that the wiring pattern on the circuit board will not be short-circuited. When an insulating material such as glass or resin is used for the supporting member, ITO or a metal film for shielding may be formed on the surface thereof.

Further, instead of the cover glass 16, a resin whose surface is hard coated may be used. Further, not all of the cover glass needs to be transparent, as long as at least a portion for reading a document is transparent.

Besides, the driving method of the image sensor is not limited at all, and the present invention is implemented in a mode in which various improvements, corrections, and modifications are added based on the knowledge of those skilled in the art without departing from the spirit of the invention. It is possible.

[0029]

[Effect of the device]

 In the image sensor according to the present invention, a supporting member having the same thickness as the sensor substrate is disposed adjacent to the sensor substrate, and a light-transmissive thin plate wider than the width of the sensor substrate in the sub-scanning direction supports the sensor substrate. Since it is arranged so as to straddle the member, the translucent thin plate ensures a width sufficient to smoothly convey the document. Therefore, the width of the sensor substrate in the sub-scanning direction can be made as narrow as possible, and the manufacturing cost of the image sensor can be significantly reduced. Moreover, since the sensor board is arranged on the circuit board, the sensor board is supported and fixed by the circuit board. Therefore, the structure is much simpler than that of the conventional image sensor, the alignment in the stacking process is easy, and the number of parts is small, so that the cost can be further reduced.

In addition, on a surface of either or both of the circuit board and the sensor board, a portion other than a light guide path for illuminating a document conveyed on the translucent thin plate from the circuit board side is provided. Since the light-shielding film is provided, light other than the reflected light from the document does not enter the photoelectric conversion element. Therefore, a high-performance image sensor with good reading accuracy can be provided at low cost. Moreover, since the frame having a simple structure can be used when it is attached to the frame and used as an image sensor unit, it is possible to reduce the size as a whole, and the present invention has excellent effects.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an image sensor according to the present invention.

FIG. 2 is a cross-sectional side view of the image sensor shown in FIG.

FIG. 3 is a cross-sectional side view showing an example of an image sensor unit using the image sensor shown in FIGS. 1 and 2.

FIG. 4 is a perspective view showing another embodiment of the circuit board used in the image sensor according to the present invention.

FIG. 5 is a sectional side view showing an example of an image sensor unit using a conventional image sensor.

[Explanation of symbols]

 10; Image sensor 12; Sensor substrate 14, 46; Circuit board 16; Cover glass (translucent thin plate) 18; Support member 20; Photoelectric conversion element 28; Light-shielding film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication H01L 23/29 23/31 H04N 1/028 Z 9070-5C 8617-4M H01L 23/30 F 8617- 4M E

Claims (2)

[Scope of utility model registration request] 1. An image sensor comprising a sensor substrate having a plurality of photoelectric conversion elements arranged in parallel, and a circuit substrate for operating the sensor substrate, wherein the sensor substrate is disposed on the circuit substrate. At the same time, a supporting member having the same thickness as the sensor substrate is arranged adjacent to the sensor substrate, and a light-transmissive thin plate wider than the width of the sensor substrate in the sub-scanning direction is provided between the sensor substrate and the supporting member. An image sensor characterized in that the image sensor is arranged so as to straddle a space. 2. A light guide path for illuminating a document conveyed on the light-transmissive thin plate on the surface of one or both of the circuit board and the sensor board from the side of the circuit board. The image sensor according to claim 1, wherein a light shielding film is provided on a portion other than the above.