JPH0734464B2 - Reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a reading device used in, for example, an image information input unit of an image processing device.

(Prior Art) In recent years, a reading device using a photoconductive thin film made of a-Si or the like for a photoelectric conversion unit is being adopted for an image information input unit of an image processing apparatus.

3 and 4 are views showing an example of such a reading device. In the figure, reference numeral 1 is a glass substrate, and a photoelectric conversion portion is formed on the glass substrate 1. That is,
A large number of individual electrodes 2 are arranged on the glass substrate 1, a photoconductive thin film 3 and a transparent electrode 4 are formed thereon, and a common electrode 5 connected to the transparent electrode 4 is arranged on the individual electrode 2. It is formed along the direction. On the other hand, a printed circuit board 7 on which a drive circuit is formed from an IC 6 that drives these photoelectric conversion units
Is arranged on the side of the individual electrode 2 and is fixed to the glass substrate 1. The connection lead 2a of the individual electrode 2 is projected toward the printed board 7 side, and the connection lead 5a of the common electrode 5 is formed.
Are protruded from the outer peripheries of both ends of the arranged individual electrodes 2 to the printed board 7 side, and the connecting leads 2a, 5a and the drive circuit of the printed board 7 are electrically connected by the bonding wires 8.

The reader thus constructed can be represented by an equivalent circuit shown in FIG. In the figure, reference numeral 5'denotes a common electrode, and this common electrode 5'is connected to an individual electrode 2'through a parallel connection circuit of a diode 3'comprising a photoconductive thin film 3 and a transparent electrode 4 and a capacitor 4 '. To be done. Further, the individual electrode 2'is connected to the drive circuit 9'via the connection lead 2a 'and the bonding wire 8'. The drive circuit 9'includes a shift register 9'a and a switching element 9'b.
It consists of and.

That is, when the switching element 9'b is turned on by the control of the shift register 9'a, the diode 3'and the capacitor 4'are reversely biased, and the potentials of the individual electrode 2'and the bonding wire 8'are at the GND level. Becomes Thereafter, the switching element 9'b is turned off by the control of the shift register 9'a, and at that time, a photocurrent flows through the diode 3'according to the amount of incident light, and the potential of the drive circuit 9'side of the capacitor 4'is changed. It changes according to this photocurrent. Then, the switching element 9'c is turned on by the control of the shift register 9'a, and the drive circuit 9'reads the change in the potential of the capacitor 4 ', and an electric signal corresponding to the amount of incident light is obtained.

(Problems to be Solved by the Invention) However, when such a reading device is used for a very long reading width such as an electronic blackboard, there is a limitation in the yield or improvement of the yield during manufacturing. For this reason, it is often the case that a plurality of glass substrates having the above-mentioned photoelectric conversion unit are joined together. In this case, when the above-mentioned connection leads of the common electrode are provided on the outer circumferences of both ends of the individual electrode, the photoelectric conversion portion becomes discontinuous due to the connection leads. Therefore, conventionally, those arranged on both sides of the plurality of glass substrates to be spliced together have the above-mentioned connection leads formed on one side of each, and those arranged inside are not formed with connection leads,
These are joined together. That is, a glass substrate having three types of photoelectric conversion parts must be formed, which affects the manufacturing cost.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a reading device capable of reducing the manufacturing cost.

[Configuration of the Invention] (Means for Solving the Invention) That is, the reading device of the present invention includes a large number of individual electrodes that are electrically arranged in a row on a substrate, and the individual electrodes are separated from each other. A common electrode extending along the row direction of the individual electrodes, a photoelectric conversion film disposed on each of the individual electrodes, and a photoelectric conversion film disposed on the photoelectric conversion film and electrically connected to the common electrode. The transparent electrode that is electrically connected to the common electrode, the drive circuit that is disposed on the side opposite to the common electrode with respect to the individual electrode, and the common electrode through the gap between at least one set of the individual electrodes from the common electrode. A reading device comprising an electrode and a connection lead for electrically connecting the drive circuit, wherein a gap between each of the individual electrodes and the connection lead is set between the individual electrode and the transparent electrode. Compared with the gap, the common electrode and the front Wherein the large enough to influence is negligible due to the leakage current between the connection leads.

(Operation) In the reading device of the present invention, the connection lead of the common electrode is
Since the connection leads and the drive circuit are electrically connected to each other by protruding through the gap between the individual electrodes to the individual electrode side, the same reading device is used when the reading width of the plural reading devices is lengthened. It can be performed by joining a plurality of pieces. Therefore, the manufacturing cost can be reduced.

(Example) Hereinafter, the detail of the Example of this invention is described based on drawing.

FIG. 1 is a partially enlarged plan view of a reading device according to an embodiment of the present invention.

The reading apparatus of this embodiment has substantially the same configuration as that shown in FIGS. 3 and 4 of the conventional example, and the same reference numerals are given to the overlapping portions and the drawings are referred to. Explain.

That is, as shown in FIGS. 3 and 4, and as shown in FIG. 1, a large number of individual electrodes 2 ... Are provided on the glass substrate 1.
The pitch is 714 μm, and the gap between the individual electrodes 2 and 2 is lined up so as to be 1/3 of the pitch, that is, 238 μm. Then, a photoconductive thin film 3 made of α-Si or the like, and a photoconductive thin film made by forming a transparent electrode 4 made of ITO or the like on the photoconductive thin film 3 are arranged thereon. Further, a common electrode 5 connected to the transparent electrode 4 is formed along the row direction of the individual electrodes 2, and these constitute a photoelectric conversion section. On the other hand, the printed circuit board 7 on which the drive circuit including the IC 6 for driving the photoelectric conversion portion is formed is the individual electrode 2 described above.
It is disposed on the side and is fixed to the glass substrate 1.

The electrical connection between the photoelectric conversion portion on the glass substrate 1 and the drive circuit for the printed board 7 is performed as follows.

First, regarding the individual electrodes 2, the connection leads 2a of these individual electrodes 2 are made to protrude toward the printed board 7 side, and these connection leads 2a and the drive circuit of the printed board 7 are electrically connected by the bonding wires 8. . On the other hand, the common electrode 5 is different from the one shown in FIGS. 3 and 4 of the conventional example, as shown in FIG. 1, in the center of the 238 μm gap between the individual electrodes 2 and 2 described above. A connecting lead 5b having a width of about 50 μm is projected from the common electrode 5 to the printed board 7 side, and the connecting lead 5b and the drive circuit of the printed board 7 are electrically connected by a bonding wire 8. It should be noted that a plurality of the connection leads 5b may be protruded toward the printed board 7 side through a plurality of gaps to be connected to the drive circuit, respectively. In this case, the electrical connection with the drive circuit is more stable. To do.

Therefore, as shown in FIGS. 3 and 4 of the conventional example,
The connecting leads 5a of the common electrode 5 do not project from the outer periphery of both ends of the individual electrodes 2 arranged in a row to the printed board 7 side, and the individual electrodes 2 can be formed almost in the vicinity of both ends of the glass substrate 1. Therefore, for example, when a reading width is very long, such as a reading device for an electronic blackboard, and a plurality of reading devices as described above must be spliced together, it is sufficient to simply splice a plurality of these reading devices together. Since only one type of reading device needs to be used, the manufacturing cost can be reduced.

In the above-described embodiment, the gap between the connection lead 5b of the common electrode 5 and the individual electrodes 2 on both sides of the connection lead 5b is about 100 μm, and the gap between the individual electrode 2 and the transparent electrode 4 is several μm. Since the value is sufficiently larger than the gap, the influence of the leakage current between the common electrode 5 and the individual electrode 2 on the signal component is negligible. That is,
A leak current, that is, a leak current from the connection lead 5b of the common electrode 5 to the individual electrode 2 is generated, and the potential of the individual electrode 2 changes due to the leak current flowing into the individual electrode 2.
This change in the potential causes a reading error and affects the signal component, that is, the read image. Here, the amount of change in the potential of the individual electrode 2 is affected by the capacitance of the capacitor 4'shown in FIG. 5 in addition to the leak current. The leak current is determined by the resistance between the connection lead 5b and the individual electrode 2, and this resistance value is proportional to the distance d1 between the connection lead 5b and the individual electrode 2. The capacitance of the capacitor 4'is inversely proportional to the distance d2 between the individual electrode 2 and the transparent electrode 4.
Therefore, if the potential change amount of the individual electrode 2 is ΔV, then ΔV α d2 / d1.

Thus, in the present invention, the gap between each of the pair of individual electrodes 2 and the connection lead 5b is sufficiently larger than the gap between the individual electrode 2 and the transparent electrode 4, that is, between the individual electrode 2 and the transparent electrode 4. Since the gap between each of the pair of individual electrodes 2 and the connection lead 5b is about 100 μm with respect to the gap of several μm, the potential change amount of the individual electrode 2 can be suppressed by ΔV, and the common electrode can be suppressed. The influence of the leakage current between the electrode 5 and the individual electrode 2 on the signal component is negligible.

Further, in this embodiment, the gap between the individual electrodes 2, 2 is set to 1/3 of the row pitch of the individual electrodes 2, and this gap hardly affects a normal read image. However, when reading a fine image having a pitch of the individual electrodes 2 arranged in rows, moire or the like may occur in the above-described gap.

FIG. 2 is a partially enlarged plan view showing a reading device according to another embodiment of the present invention which prevents the occurrence of such moire. As shown in the figure, the individual electrodes 2, 2 of this reader are
The gap between these individual electrodes 2 is 1 at a pitch of 714 μm.
/ 10 is 71 μm. The gap between the individual electrodes 2 and 2 with the connecting lead 5b of the common electrode 5 interposed therebetween is the same as in the embodiment shown in FIG.
It is set to 238 μm, which is 1/3 of the above. Then, a connection lead 5b having a width of about 50 μm is interposed substantially at the center of this gap. Further, the individual electrode 2 having the connection lead 5b of the common electrode 5 interposed in this gap becomes narrow due to the gap being 238 μm as described above, and a difference in sensitivity occurs as compared with the other individual electrodes 2. Therefore, the reading direction is lengthened so that the area of the narrow individual electrode 2 is equal to that of the other individual electrode 2.

Thus, according to this embodiment, the individual electrodes 2 having a reduced width are
The position of is shifted by about 8% from the positions of the other individual electrodes 2, but it is a sufficiently small value compared with the allowable value of the displacement ± 25% when considering the influence of the read image, and the read image Can be ignored.

In this embodiment, only the individual electrode 2 having the connection lead 5b in the gap is narrowed. However, when the pitch of the individual electrode 2 is further reduced for high resolution, that is, the narrowed individual electrode is used. When it becomes necessary to use the position of the electrode 2 to the limit of ± 25% which is the allowable amount of positional deviation compared to the positions of other individual electrodes 2, only the individual electrode 2 having the connecting lead 5b in the gap is used. Not a few individual electrodes 2 in the vicinity
By gradually narrowing the shape of the image as it approaches the connection lead 5b, it is possible to reduce the deterioration of the image quality of the read image.

According to the above-described embodiments, the narrowing of the individual electrode 2 was intended to interpose the connection lead 5b, but by narrowing the individual electrodes 2 formed on both ends of the glass substrate 1, It is possible to prevent the individual electrodes 2 from not being formed on both ends of the glass substrate 1 due to the unevenness formed when cutting the both ends.

[Effects of the Invention] As described above, according to the reading device of the present invention, when the reading width is very long and a plurality of reading devices must be spliced together like the reading device of the electronic blackboard, the present invention It suffices to simply splice a plurality of reading devices, that is, to manufacture one type of reading device. Therefore, the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a partially enlarged plan view of a reading device according to an embodiment of the present invention, FIG. 2 is a partially enlarged plan view of a reading device according to another embodiment of the present invention, and FIG. 3 is a conventional reading device. A plan view of the device,
FIG. 4 is a vertical side view of FIG. 3, and FIG. 5 is an equivalent circuit of FIGS. 3 and 4. 2 ... Individual electrode 5 ... Common electrode 2a, 5b ... Connection lead

Claims (2)

[Claims] 1. A large number of individual electrodes that are electrically individually arranged on a substrate, and a common unit that is separated from the individual electrodes and that extends along the direction in which the individual electrodes are arranged. An electrode, a photoelectric conversion film arranged on each of the individual electrodes, a transparent electrode arranged on the photoelectric conversion film and electrically connected to the common electrode, and the common for the individual electrodes A driving circuit disposed on a side opposite to the electrodes; and a connection lead electrically connecting the common electrode and the driving circuit from the common electrode through a gap between at least one set of the individual electrodes. And a gap between each of the individual electrodes of the pair and the connection lead is larger than a gap between the individual electrode and the transparent electrode,
A reading device, wherein the influence of a leak current between the common electrode and the individual electrode on a signal component is sufficiently large to be negligible. 2. The individual electrodes have substantially the same electrode area, and the pair of individual electrodes have a narrow electrode width in the row direction. The reading device according to the item.