JPH09462U - Image reading device - Google Patents

Abstract

The image sensor itself corrects a specific increase in the image signal corresponding to the block edge of the photoelectric conversion element without the need for a complicated output signal correction circuit, and a good image of the output signal is obtained. To provide an image reading device having a sensor. SOLUTION: The image sensor itself is provided with a means for correcting the inter-wiring capacitance of a specific lead wire in the image sensor, and the image sensor using the output signal correction circuit using a memory element or the like is unnecessary. There is.

Description

[Detailed description of the device]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an image reading device including an image sensor.

[0002]

[Prior art]

 In recent years, a contact image sensor has been used as an image reading device for various OA devices such as a facsimile and a copier.

This contact image sensor reads a manuscript in a one-to-one manner. The photoelectric conversion elements are arranged in a line in the width of the manuscript and either the manuscript or the photoelectric conversion element is moved to read characters and images. It has become. There are CdS, CdSe, Se-As-Te system, a-Si (amorphous silicon), etc. as the material constituting the photoelectric conversion element. In particular, the structure of an image sensor using a-Si is generally flat and sandwiched. There is a mold. In the sandwich type, a pixel electrode, a transparent conductive film such as a-Si and ITO are sequentially laminated on a glass substrate to form a charge storage type photoelectric conversion element.

A lead wire is connected to the photoelectric conversion element of the image sensor, and a bonding pad is formed at the tip of the lead wire. Further, the bonding pad is connected to the driving IC by a bonding wire. However, the pitch between the photoelectric conversion elements arranged continuously and the pitch of the pad of the IC do not match. For this reason, as shown in FIG. 5, the lead wire 6 is arranged so that the photoelectric conversion element 5 is divided into blocks according to the number of input terminals 9 of the driving IC 8.

[0005]

[Problems to be solved by the device]

 According to the above conventional configuration, the inter-wiring capacitance for each photoelectric conversion element is mainly generated between the adjacent lead wires. Therefore, the wiring capacitance is specifically reduced at the block end, and the image signal of the photoelectric conversion element corresponding thereto is specifically increased. Therefore, in order to correct such variations in the output signal, it was necessary to connect an output signal correction circuit using a memory element or the like below the output terminals of the image sensor external device or the image sensor drive circuit section. .

An object of the present invention is to eliminate the above-described complicated output signal correction circuit, and to correct the specific increase of the image signal corresponding to the block end of the photoelectric conversion element by the image sensor itself and Another object is to provide an image reading device having a good image sensor.

[0007]

[Means for Solving the Problems]

 In order to solve such a problem, the image reading apparatus of the present invention is provided with an output signal correction circuit using a memory element or the like by providing the image sensor itself with means for correcting the inter-wiring capacitance of a specific lead wire in the image sensor. It is characterized by using an image sensor that does not require the connection.

[0008]

[Embodiment of the invention]

 Hereinafter, an embodiment of an image sensor according to the present invention will be described with reference to the drawings. FIG. 2 shows the structure of the photoelectric conversion element section. In this image sensor, a large number of pixel electrodes 11 and lead wires 6 made of a Cr thin film are linearly arranged on a glass substrate 1, a-Si: H film 3 is formed on the pixel electrodes 11, and an ITO transparent electrode is formed thereon. It is manufactured by sequentially stacking the membranes 4. As a result, a plurality of photoelectric conversion elements are arranged and formed in a straight line. As for the lead wire 6, as will be described later, the capacitance correction pattern 2 is formed on the lead wire 6 arranged at the block end, for example, the N + 1th block end (see FIG. 1).

This structure is particularly suitable for the charge storage system, and when the sensor element is irradiated with light, electrons are excited in the a-Si: I film 3, and the stored charge amount is reduced. Then, the amount of light can be measured by reducing the accumulated charge amount.

Next, FIG. 4 shows an equivalent circuit diagram showing an output reading method of the charge storage method. The element portion has a diode characteristic due to a Schottky barrier and has an element capacitance Cs between the pixel electrode 11 and the transparent electrode 4.

In the initial state, the bias voltage Vb causes charges of Qo = Cs Vb to be accumulated in the element. Then, a current flows between the transparent electrode and the pixel electrode depending on the amount of incident light. The image output signal Vout is represented by Vout = ΔQ /, where Ca is the change amount of charge ΔQ according to the amount of incident light, the inter-wiring capacitance Cl of the lead wire, and the capacitance of the drive circuit system such as IC connected to the lead wire. (Cs + Cl + Ca). Thus, the output signal is obtained not only by the photoelectric conversion element characteristics ΔQ and Cs but also by the inter-wiring capacitance Cl of the lead electrode.

As shown in FIG. 1, in this image sensor, a bonding pad 7 having the same pitch as the input terminal pad 9 of the input of the driving IC 8 is formed at the tip of the lead wire 6, and a bonding wire 10 is used from there. It is connected to the input terminal pad 9 of the IC 8. The drive control terminal of the drive IC 8 will not be particularly described. Further, reference numeral 5 in the figure denotes a photoelectric conversion element. By the way, in the prior art shown in FIG. 5, the pitches of the lead wires 6 at the block ends are not equal, and the inter-wiring capacitance Cl of the lead wires 6 there is about 1 of the inter-wiring capacitances of the other lead wires 6. It becomes / 2. However, as shown in FIG. 1, the capacitance correction pattern 2 is further formed on the lead wire 6 arranged at the block end, for example, the (N + 1) th block end. In this embodiment, the capacitance correction pattern 2 is formed with the same shape and the same pitch as the lead wires 6.

With such a capacitance correction branch pattern 7, it is possible to solve the problem that the pitch between the lead wires 6 that are continuously arranged becomes equal and the inter-wiring capacitance at the block end decreases. That is, the inter-wiring capacitance between the lead lines 6 which are arranged at the end of each block of the adjacent blocks and which oppose each other is compensated. Then, the inter-wiring capacitance for each photoelectric conversion element 5 becomes substantially uniform, so that it is possible to correct the peculiar decrease in the conventional inter-wiring capacitance and also to correct the variation in the image signal.

It should be noted that the capacitance correction patterns 2 may be provided not only on one of the photoelectric conversion elements 5 arranged at the ends of each block and facing each other as shown in FIG.

As described above, a contact image sensor is used as an image reading device for various OA devices such as facsimiles and copiers. This image sensor is used in various image reading devices such as facsimiles and copiers. Can be used. In other words, if the image sensor with the above-mentioned configuration is used in various image reading devices such as facsimiles and copiers, output signal correction using a memory element or the like for correcting output signal variations in the subsequent stage of the image sensor. There is no need to connect circuits.

[0016]

[Effect of the invention]

 As described above in detail, according to the present invention, the image sensor itself is provided with a means for correcting the specific inter-wire capacitance of the lead wire in the image sensor, and the output signal correction circuit using a memory element or the like is connected. Since an unnecessary image sensor is used, a complicated output signal correction circuit is not required, and the image sensor itself corrects the specific increase in the image signal corresponding to the block edge of the photoelectric conversion element, and the output signal is good. It is possible to provide an image reading device having a different image sensor.

[Brief description of drawings]

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

FIG. 2 is a partially cutaway perspective view of a photoelectric conversion element part according to the present invention.

FIG. 3 is a plan view showing another embodiment of the present invention.

4 is an equivalent circuit diagram showing an output reading method of the image sensor shown in FIG.

FIG. 5 is a plan view showing a main part of a conventional image sensor.

[Explanation of symbols]

 1 Glass substrate 2 Capacitance correction pattern 3 a-Si: H film 4 ITO 5 Photoelectric conversion element 6 Lead wire 7 Bonding pad 11 Pixel electrode

Claims (1)

[Utility model registration claims] 1. The image sensor is provided with means for correcting the inter-wiring capacitance of a specific lead wire in the image sensor, and an image sensor which does not require connection of an output signal correction circuit using a memory element or the like is used. An image reading device characterized by the above.