JPH0744026Y2 - Image sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention relates to a charge storage type image sensor using a photoelectric conversion element.

(Prior Art) In recent years, a contact image sensor has been used as an image reading device for various office automation equipment such as facsimiles and copiers.
This contact image sensor reads a manuscript one-to-one, and 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 a character and an image. 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 the image sensor using a-Si is generally flat and sandwich type. There is. In the sandwich type, a pixel electrode and a transparent conductive film such as a-Si and ITO are sequentially stacked 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 butt is connected to the driving IC by a bonding wire. However, the pitch between the continuously arranged photoelectric conversion elements and the pitch of the IC pads are not in agreement. Therefore, as shown in FIG.
The photoelectric conversion element (5) is the input terminal (9) of the driving IC (8).
The lead wires (6) are arranged so as to be divided into blocks according to the number.

(Problems to be Solved by the Invention) According to the above-described conventional configuration, the inter-wiring capacitance for each photoelectric conversion element mainly occurs 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 is necessary to connect an output signal correction circuit using a memory element or the like below the output terminal of the image sensor external device or the image sensor drive circuit unit.

The object of the present invention is to correct the specific increase of the image signal corresponding to the block end of the photoelectric conversion element by the image sensor itself without the need for the complicated output signal correction circuit described above, and to provide an image sensor with a good output signal. To provide.

[Constitution of device]

(Means for Solving Problems) The image sensor of the present invention is characterized in that the photoelectric conversion element connected to the lead wire at the block end is provided with the capacitance correction pattern.

(Operation) In the configuration as described above, the specific reduction of the inter-wiring capacitance for the photoelectric conversion element at each block end is corrected, and the variation of the image signal of the photoelectric conversion element is prevented.

Embodiment An embodiment of the image sensor of the present invention will be described below with reference to the drawings.

FIG. 2 shows the structure of the photoelectric conversion element part, in which a large number of pixel electrodes (11) and lead wires (6) made of a Cr thin film are linearly arranged and formed on the glass substrate (1).
An a-Si: H film (3) and an ITO transparent electrode film (4) are laminated on top, and a plurality of photoelectric conversion elements are linearly arranged and formed. 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: H film (3) and the stored charge amount is reduced. Then, the amount of light can be measured by the decrease in the amount of accumulated charges.

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

In the initial state, the bias voltage V _b causes the device to store a charge of Q _o = C _s V _b . Then, a current flows between the transparent electrode and the pixel electrode depending on the amount of incident light. Image output signal Vout
The amount of charge variation ΔQ in accordance with the incident light amount, the capacitance between the leads wires C _l, the capacity or the like having a drive circuit system such as an IC connected to Lisi line and C _a, Becomes Thus, the output signal is obtained not only by the photoelectric conversion element characteristics ΔQ, C _s but also by the inter-wiring capacitance C _l of the lead electrode.

Now, in the image sensor of this embodiment, as shown in FIG. 1, the bonding pad (9) having the same pitch as the input terminal pad (9) of the input of the driving IC (8) is provided at the tip of the lead wire (6). 7) is formed, and then the input terminal pad (9) of the IC (8) is formed by the bonding wire (10).
Connected to. The drive control terminal of the drive IC (8) will not be described in particular. Further, (5) in the figure indicates 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 different from that of the other lead wires (6). Approximately 1/2 of the capacitance between wires
become. However, as shown in FIG. 1, in the present invention, 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 pitch as the lead wire (6).

Such a capacitance correction branch pattern (7) can solve the problem that the pitch between the lead wires (6) arranged continuously becomes equal and the inter-wiring capacitance at the block end decreases. That is, the inter-wiring capacitance between the lead wires (6) arranged at each block end of the adjacent block and facing 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 capacity and also to correct the variation in the image signal.

Note that, as shown in FIG. 3, the capacitance correction pattern (2) may be provided not only on one of the photoelectric conversion elements (5) arranged at the end of each block but facing each other.

[Effect of device]

As is clear from the above description, according to the image sensor of the present invention, since it is possible to correct the wiring capacitance of a specific lead wire, it is not necessary to provide a complicated output signal correction circuit,
An image sensor having good output characteristics can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an essential part showing an embodiment of an image sensor of the present invention, FIG. 2 is a partially cutaway perspective view of a photoelectric conversion element part according to the present invention, and FIG. Is a plan view showing another embodiment of the present invention, FIG. 4 is an equivalent circuit diagram showing an output reading method of the image sensor shown in FIG. 1, and FIG. 5 is a plan view showing a main part of a conventional image sensor. is there. 1 ... Glass substrate, 2 ... Capacitance correction pattern 3 ... a-Si: H film, 4 ... ITO 5 ... Photoelectric conversion element, 6 ... Lead wire 7 ... Bonding pad 8 ... Driving IC, 9 …… Input terminal pad 11 …… Pixel electrode

Claims (1)

[Scope of utility model registration request] 1. A first driving IC having a plurality of first terminals arranged at a first pitch, and a second pitch larger than the first pitch corresponding to the first driving IC. A first block including a first photoelectric conversion element group including a plurality of first photoelectric conversion elements, and a plurality of first lead wires electrically connecting each of the first photoelectric conversion elements and each of the first terminals A second driving IC having a plurality of second terminals arranged at the first pitch and arranged in proximity to the first driving IC, and the second driving IC corresponding to the second driving IC. A second photoelectric conversion element group composed of a plurality of second photoelectric conversion elements arranged at the second pitch so as to be arranged substantially linearly with one photoelectric conversion element group;
An image sensor including at least a second block including a plurality of second lead wires electrically connecting each of the second photoelectric conversion elements and each of the second terminals, the first sensor being adjacent to each other. In a region between the lead wire and the second lead wire, the first lead wire or the second lead wire is formed integrally with the first lead wire side and the first photoelectric conversion element group side. A capacitance correction branch pattern extending from the second lead wire side to the first terminal side or the second terminal side, the second photoelectric conversion element group side to the second terminal side or the first terminal side, or Formed integrally from each of the first lead wire and the second lead wire, from the first lead wire side to the first photoelectric conversion element group side to the first terminal side, and from the second lead wire side. The second
An image sensor comprising a capacitance correction branch pattern extending from the photoelectric conversion element group side to the second terminal side.