JPH05251681A - Image sensor - Google Patents

Abstract

PURPOSE:To have a narrow width of an image sensor, moreover a small number of wire bondings required at the time of modulation, further allowing the use of a general-purpose driving IC. CONSTITUTION:While dividing driving terminals 24 in the end parts of driving wirings 20 every fixed number and arranging en bloc in a plurality of places on a substrate 12, these driving terminals 24 and the read wirings 26 in the terminal parts of the read wirings 22 are arranged on one side of the substrate 12. Thereby, the driving terminals 24 and the general-purpose driving IC are enabled to be directly connected by wire bondings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor,
More specifically, 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.

[0002]

2. Description of the Related Art Recently, in a document reading section of a facsimile or the like, a contact type image sensor for reading a document through an erecting equal-magnification lens has been used instead of a CCD image sensor for reading a document through a reduction optical system. Widely used.

As the contact type image sensor, as shown in FIGS. 9 (a) and 9 (b), for example, a matrix drive type is mainly used. This image sensor 100 is
A plurality of photodiodes 104 and blocking diodes 106 are formed one-dimensionally on a glass substrate 102 and are divided into a plurality of blocks 108 in a fixed number. The blocking diodes 106 are connected to a block 10 by a drive wiring 110.
The photodiodes 104 are commonly connected in units of 8 units, and the photodiodes 104 are commonly connected by the readout wiring 112 between the blocks 108 that are at the same position. At the end of the drive wiring 110 of the image sensor 100, the drive IC
A drive terminal 114 for connecting (118) is provided, and a read terminal 116 for connecting a read IC (120) is provided at an end of the read wiring 112.

As shown in FIG. 10, the image sensor 100 is attached to a printed wiring board 122 on which a driving IC 118, a reading IC 120, etc. are mounted and used as an image sensor module 124. The drive terminal 114 is connected to the external drive wiring 126 formed on the printed wiring board 122 by wire bonding, and the external drive wiring 126 is connected to the drive IC 118 by wire bonding. On the other hand, the read terminal 116 is connected directly to the read IC 12 by wire bonding.
Connected with 0.

[0005]

As described above, the conventional image sensor 100 has a problem of high cost because it is necessary to perform a large number of wire bondings. For example, if the total number of photodiodes 104 is 1728 and these are divided into 108 blocks 108 for every 16 photodiodes, the number of drive terminals 114 is 108. It was necessary to perform bonding. Further, since the external drive wiring 126 is routed on the printed wiring board 122, there is also a problem that the output is varied due to noise on the printed wiring board 122 side, so that it is susceptible to noise.

On the other hand, as shown in FIG. 11, the drive wiring 128 is formed on the glass substrate 130 and these drive terminals are formed.
There was an image sensor 134 formed by arranging 132 on one side of a glass substrate 130. In this case, since the drive terminals 132 and the drive ICs 120 may be directly connected by wire bonding, the number of wire bondings is reduced. However, for example, when there are 108 blocks 108, the number of drive wirings 128 is 108. Therefore, the width of the image sensor 134 in the short side direction becomes extremely wide. For this reason,
There is a problem in that the number of image sensors 134 that can be manufactured from one large substrate is small, which is extremely disadvantageous in terms of cost. In this way, any image sensor 100,134
However, there are merits and demerits, so it was the actual situation that they were used properly considering quality and cost.

Generally, image sensors include A4, B4,
Since there are various sizes such as the A3 size, and the number of blocks varies depending on the size, it is necessary to manufacture a dedicated drive IC adapted to each size. Therefore, not only is it extremely expensive, but the design, manufacturing, and
It was also very inconvenient in terms of management.

Therefore, the present inventors have solved these problems, and have a high S / N ratio even if the width is narrow, and the number of wire bondings to be modularized is small, and an inexpensive drive IC can be used. As a result of intensive studies to provide an image sensor, the present invention has been achieved.

[0009]

The gist of an image sensor according to the present invention is that a plurality of photoelectric conversion elements are formed one-dimensionally on a substrate, and the photoelectric conversion elements are divided into a plurality of blocks at a constant number. One of the photoelectric conversion elements is commonly connected in block units from the drive wiring, and the other of the photoelectric conversion elements is commonly connected to those in the same position between the blocks by the read wiring. In the image sensor configured as described above, the drive terminals at the ends of the drive wiring are divided into a predetermined number, and the drive terminals are collectively disposed at a plurality of locations on the substrate.

Further, in the image sensor, the drive terminal at the end of the drive wiring and the read terminal at the end of the read wiring are arranged on one side of the substrate.

Further, in the image sensor, a dummy wiring is arranged near at least one of the drive wiring and the read wiring.

Further, in such an image sensor, the readout wiring and the extraction wiring led out from the photoelectric conversion element are connected through a plurality of contact holes, and the line width of the readout wiring at this connection portion is the readout width. It is made wider than the line width in other parts of the wiring.

Further, in such an image sensor,
The image sensor is a contact type image sensor that reads an original through a lens of an upright size.

[0014]

According to such an image sensor, since the drive terminals are divided into a predetermined number and are collectively arranged at a plurality of positions on the substrate, the drive ICs can be directly connected to these drive terminals by wire bonding. The number of is small. Further, since these drive ICs are connected to a predetermined number of drive terminals, the same drive IC can always be used regardless of the size of the image sensor. Furthermore, even if the total number of drive wirings is large, the drive terminals at the end portions are arranged separately, so that the width of the image sensor does not become extremely wide. Further, since the drive wiring is formed on the glass substrate, it is less likely to be affected by noise.

On the other hand, since the drive terminal and the read terminal are arranged on one side of the substrate, the width of the image sensor is further narrowed. Further, although the noise is reduced by the dummy wiring, the noise caused by the non-uniform stray capacitance generated between the driving wirings is significantly reduced especially by the dummy wiring arranged near the driving wiring. Become. Further, since the read wiring and the lead wiring are connected through a plurality of contact holes and the line width of the read wiring is widened at the connection portion, low resistance and stable contact resistance can be obtained.
The variation between the bright output and the dark output becomes small, and the SN ratio becomes high.

[0016]

Embodiments of the image sensor according to the present invention will now be described in detail with reference to the drawings.

In FIG. 1, reference numeral 10 is an embodiment of the image sensor according to the present invention. This image sensor 1
Reference numeral 0 denotes a plurality of photodiodes (photoelectric conversion elements) 14 and blocking diodes 16 on a substrate 12 such as glass.
Are formed one-dimensionally and are divided into a plurality of blocks 18 by a fixed number, and the anode electrodes of the blocking diodes 16 are commonly connected to each block 18 by the drive wiring 20, and the anode electrodes of the photodiodes 14 are read out. The wirings 22 are commonly connected to each other at the same position among the blocks 18.

In this image sensor 10, the drive wiring 2
The drive terminals 24 at the end portion of 0 are divided into a predetermined number and are collectively arranged at a plurality of positions on the substrate 12.
This is the greatest feature of this embodiment. In addition, the drive terminal 24 and the read terminal 2 at the end of the read wiring 22.
6 is disposed so as to face only one long side of the substrate 12.

As shown in FIG. 2, the image sensor 10 is attached to a printed wiring board 28 and used as an image sensor module 30. A plurality of drive ICs 32 corresponding to the drive terminals 24 of the image sensor 10 are mounted on the printed wiring board 28, and the drive ICs 32 and the drive terminals 24 are directly connected by wire bonding. A read IC 34 is also mounted on the printed wiring board 28, and the read IC 34 and the read terminal 26 of the image sensor 10 are directly connected by wire bonding. Therefore, compared with the conventional image sensor module 124, the number of wire bondings is almost halved.

Further, since these drive ICs 32 are connected to a predetermined number of drive terminals 24, the same drive ICs are always used for the image sensor 10 of any size.
Can be used. Therefore, it is not necessary to manufacture a dedicated drive IC according to the size of the image sensor as in the conventional case. In other words, if only one type of required driving IC is manufactured, it can be applied to image sensors of any size, which makes it extremely inexpensive. In addition, the design, manufacturing, and management of the image sensor will be extremely easy.

For example, in an A4 size image sensor having a resolution of 8 dots / mm, the number of photodiodes and blocking diodes is 17 each.
Since the number of drive terminals is 28, the number of drive terminals is 108 when these are divided into groups of 16. Therefore, when a drive IC having 28 terminals per one is used, the drive terminals are divided into every 28 pieces and are collectively arranged at four places on the substrate, so four drive ICs are required. Becomes However, 4 of these (28 × 4-108
= 4), the remaining terminals can be treated as unused terminals. As described above, in the image sensor 10, the same number of drive terminals 24 as the terminals provided in the drive IC 32 may be collectively formed in a predetermined region on the substrate 12.

Further, in the case of a B4 size image sensor, only the same five driving ICs as described above are required, and it is not necessary to separately prepare a dedicated driving IC. In this way, even if the size of the image sensor is different, the driving I
The module can be modularized by simply increasing or decreasing the number of C. Further, since the size of each of these drive ICs is smaller and cheaper than the dedicated drive IC, the total cost is low despite the number of drive ICs being plural.

Further, since these drive wirings 20 are formed on the substrate 12, they are less susceptible to noise as compared with the case where they are formed on the printed wiring board. Also,
Since the drive terminals 24 are arranged in a divided manner in the long side direction of the substrate 12 and the drive wirings 20 are also arranged in a divided manner, the drive wirings 2 are arranged like the conventional image sensor 134.
With 0, the width in the short side direction does not increase. Therefore, the number of image sensors 10 that can be manufactured from one large substrate is large, which is extremely advantageous in terms of cost. Further, since the drive terminal 24 and the read terminal 26 are provided on one side of the substrate 12, the width of the image sensor 10 is narrower.

On the other hand, as shown in FIG. 3, the connection portion 3 between the readout wiring 22 of the image sensor 10 and the extraction wiring 36 drawn out from the anode electrode of the photodiode 18 is connected.
In FIG. 8, the read wiring 22 and the lead wiring 36 are connected via three contact holes 40, and
The line width of the read wiring 22 in the connecting portion 38 is made wider than the line width of the read wiring 22 in other portions. Therefore, the contact area between these wirings 22 and 36 is large, and low resistance and stable contact resistance can be obtained. Further, not only the contact failure is reduced, but also the variation between the bright output and the dark output is reduced, and a stable output with a high SN ratio can be obtained. At the intersection of the read wiring 22 and the lead wiring 36, the line width of each of them is made narrower than the line width of other portions to prevent capacitive coupling between the read wiring 22 and the lead wiring 36. You may make it reduce as much as possible.

The image sensor 10 has a structure as shown in FIG. That is, the photodiode 14 and the blocking diode 16 are both composed of the same amorphous silicon semiconductor layer 42, and the transparent electrode 44 made of ITO is formed on the upper surface of these semiconductor layers 42. The photodiode 14 and the blocking diode 16 are covered with a transparent interlayer insulating film 46 made of SiOx or the like, and further connected with a connection wiring 50 through a contact hole 48 formed in the transparent interlayer insulating film 46. There is. Further, the whole of them is covered with an insulating protective film 52 made of SiNx or the like.

The image sensor 10 is used by being attached to a document reading section such as a facsimile, and an erecting equal-magnification image of the document is formed on the photodiode 14 by a converging rod lens array or the like. It is a contact image sensor that reads

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

For example, as shown in FIG. 5, dummy wirings 54 may be arranged near the driving wirings 20 arranged together. Unlike the conventional case where all the drive wirings are arranged at equal intervals, when the drive wirings 20 are collectively arranged at a plurality of locations, the non-uniform stray capacitance is present between the drive wirings 20. As a result, the line impedance of each drive wiring 20 may vary, which may cause noise. Therefore, if such dummy wiring 54 is provided, variations in output between the drive ICs 32 are reduced, and noise is also reduced.

It is preferable that these dummy wirings 54 are connected to the ground, but for the first and last dummy wirings 54a and 54b, the surplus terminals of the driving IC 32 are connected and the normal driving wirings are connected. Before and after the drive pulse is applied to 20, the drive pulse may be applied to the dummy wirings 54a and 54b. In this case, the capacitance kick accompanying the rising of the drive pulse applied to the first drive wiring 20 is offset by the falling of the drive pulse applied to the first dummy wiring 54a, and the rise of the drive pulse applied to the last drive wiring 20 is offset. The capacitance kick accompanying the fall is the last dummy wiring 54b.
The noise is significantly reduced by being offset by the rising edge of the drive pulse applied to.

Further, as shown in FIG. 6, not only the dummy wiring 54 is provided near the drive wiring 20, but also the read wiring 2 is provided.
The dummy wiring 56 may be arranged in the vicinity of 2, and the dummy wiring 56 may be arranged only in the vicinity of the read wiring 20, as shown in FIG. By these, the read wiring 20
The noise generated on the side will be reduced.

Further, as shown in FIG.
The dummy wiring 58 may be arranged so as to surround the entire drive wiring 20 and read wiring 22. Also in this case, noise is reduced as in the above case. The loop-shaped dummy wiring 58 is used as the driving wiring 20 and the read wiring 2.
It is considered that the dummy wirings arranged in the vicinity of both 2 are connected to each other.

Further, although the above-mentioned drive wiring 20 is bent in a stepwise shape, it is not limited to such a shape, and for example, the drive terminal 24 and the block 1 are provided.
It may be shaped so as to connect with 8 in a straight line.

On the other hand, although not shown, the photodiode and the blocking diode are connected to each other through their anode electrodes, the cathode electrode of the blocking diode is commonly connected in a block unit by the drive wiring, and the cathode electrode of the photodiode is connected to the read wiring. Accordingly, the blocks may be commonly connected to each other at the same position between the blocks. Further, the anode electrode or the cathode electrode of the photodiode is commonly connected in a block unit by the drive wiring, and the anode electrode or the cathode electrode of the blocking diode is shared by the read wirings at the same relative positions between the blocks. It may be connected to. That is, one of the photodiodes, which is a photoelectric conversion element, is directly or indirectly connected in common in block units by a drive wiring, and the other of the photodiodes is directly or indirectly located at the same position between blocks by a read wiring. It is only necessary that they are commonly connected.

Besides, a TFT may be used instead of the blocking diode, and a photoconductive CdS-CdSe or the like may be used as a photoelectric conversion element. Further, the present invention can be applied not only to the contact type image sensor but also to a complete contact type image sensor.
The present invention can be implemented with modifications and variations.

[0035]

In the image sensor according to the present invention, the drive terminals are divided into a predetermined number and are arranged collectively at a plurality of positions on the substrate. Therefore, the drive terminals and the drive ICs are directly connected by wire bonding. It is possible to reduce the number of wire bondings as compared with the conventional method. Therefore, the manufacturing cost can be significantly reduced. In addition, since it is not necessary to manufacture a dedicated drive IC according to the size of the image sensor, the same drive IC can be always used regardless of the size of the image sensor. As a result, the number of drive ICs becomes plural, but the cost is sufficiently low as compared with the case where one dedicated drive IC corresponding to each size is used. In addition, image sensor design, manufacturing,
It is also extremely easy to manage.

Further, since the drive terminals are arranged separately, the width of the image sensor does not become extremely wide. Therefore, a large number of image sensors can be manufactured from one large substrate, which is advantageous in terms of cost. Further, since the drive wiring is formed on the glass substrate, it is not easily affected by noise.

Further, since the drive terminal and the read terminal are arranged on one side of the substrate, the width of the image sensor becomes narrower. Further, since the dummy wiring is arranged near the drive wiring and the like, noise is reduced and the image sensor has a high SN ratio. Further, since the read wiring and the lead wiring are connected through a plurality of contact holes and the line width of the read wiring is widened at this connection portion, a low resistance and a stable contact resistance are obtained, and a stable output is obtained. It becomes a high-performance image sensor.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an image sensor according to the present invention, in which FIG.
FIG. 2B is a wiring diagram of the block.

FIG. 2 is a plan view showing an image sensor module using the image sensor shown in FIG.

FIG. 3 is a plan view showing a part of the image sensor shown in FIG. 1 in an enlarged manner.

FIG. 4 is a cross-sectional view showing the structure of the image sensor shown in FIGS. 1 and 3.

FIG. 5 is a layout view showing another embodiment of the image sensor according to the present invention with a part thereof broken away.

FIG. 6 is a layout view showing still another embodiment of the image sensor according to the present invention with a part thereof broken away.

FIG. 7 is a layout view showing still another embodiment of the image sensor according to the present invention with a part thereof broken away.

FIG. 8 is a layout view showing still another embodiment of the image sensor according to the present invention with a part thereof broken away.

FIG. 9 is a diagram showing an example of a conventional image sensor,
Part (a) of the same drawing is a layout diagram showing a part of the block, and part (b) of FIG. 1 is a wiring diagram of the block.

FIG. 10 is a plan view showing an image sensor module using the image sensor shown in FIG.

FIG. 11 is a layout view showing another example of the conventional image sensor with a part thereof cut away.

[Explanation of symbols]

 10; Image Sensor 12; Substrate 14; Photodiode (Photoelectric Conversion Element) 18; Block 20; Drive Wiring 22; Readout Wiring 24; Drive Terminal 26; Readout Terminal 36; Lead Out Wiring 38; Connection Part 40; Contact Holes 54, 56 , 58; dummy wiring

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[Procedure amendment]

[Submission date] April 17, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

As the contact type image sensor, as shown in FIGS. 9 (a) and 9 (b), for example, a matrix drive type is mainly used. This image sensor 100 is
A plurality of photodiodes (photoelectric conversion
(Element) 104 and blocking diode 106 are formed one-dimensionally and are divided into a plurality of blocks 108 by a fixed number.
Are connected in common for each block 108, and the photodiodes 104 are connected in common by the read wiring 112 between the blocks 108 at the same position. At the end of the drive wiring 110 of the image sensor 100, a drive terminal 114 for connecting a drive IC (118).
Is provided, and the read IC (120) is provided at the end of the read wiring 112.
A read terminal 116 is provided for connecting to. Note that
Here, the photodiode 104, which is a photoelectric conversion element,
One indirectly driven via blocking diode 106
Wiring 110 is commonly connected to each block 108
The other side of the photodiode 104, which is a photoelectric conversion element, directly
The read wiring 112 allows the blocks 108 to be relatively in the same position.
It means that they are commonly connected to each other.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

The gist of an image sensor according to the present invention is that a plurality of photoelectric conversion elements are formed one-dimensionally on a substrate, and the photoelectric conversion elements are divided into a plurality of blocks at a constant number. have been classified, one is connected commonly by more blocks to the driving line directly or indirectly the photoelectric conversion element, relative between blocks other photoelectric conversion element by <br/> read wire directly or indirectly In an image sensor that is commonly connected to those at the same position, the drive terminals at the ends of the drive wiring are divided into a predetermined number, and are arranged collectively at a plurality of positions on the substrate. It is in.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

In FIG. 1, reference numeral 10 is an embodiment of the image sensor according to the present invention. This image sensor 1
Reference numeral 0 denotes a plurality of photodiodes (photoelectric conversion elements) 14 and blocking diodes 16 on a substrate 12 such as glass.
Are formed one-dimensionally and are divided into a plurality of blocks 18 by a fixed number, and the anode electrodes of the blocking diodes 16 are commonly connected to each block 18 by the drive wiring 20, and the anode electrodes of the photodiodes 14 are read out. The wirings 22 are commonly connected to each other at the same position among the blocks 18.
That is, in the present embodiment, a photo die which is a photoelectric conversion element is used.
One of the odes 14 through the blocking diode 16
And indirectly through the drive wiring 20 in common for each block 18
Of the photodiode 14 which is connected and is a photoelectric conversion element.
The other is directly connected between the blocks 18 by the read wiring 22.
Are commonly connected to each other at the same position.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

On the other hand, although not shown, the photodiode
The cathode and blocking diode contact each other.
The anode electrode of the photodiode is connected to the drive wiring.
More commonly connected in blocks, blocking die
The anode electrode of the anode is connected between the blocks by the readout wiring.
Those connected in common to each other at the same position
But it's okay. In addition, the photodiode and the blocking diode are connected to each other through the anode electrodes, the cathode electrode of the blocking diode is commonly connected in a block unit by the drive wiring, and the cathode electrode of the photodiode is relatively located between the blocks by the read wiring. The same may be connected to each other. In addition,
Photodiode and blocking diode are anodes
The electrodes are connected to each other, and the cathode electrode of the photodiode
Are commonly connected in block units by the drive wiring.
The cathode electrode of the locking diode is blocked by the read wiring.
Commonly connect locks that are relatively in the same position
It may be continued. That is, one of the photodiodes, which is a photoelectric conversion element, is directly or indirectly connected in common in block units by drive wiring, and the other of the photodiodes is directly or indirectly located at the same position between the blocks by read wiring. It is only necessary that they are commonly connected. In addition, the charge storage type
CdS-Cd as photoelectric conversion element as well as image sensor
It can also be applied to photoconductive image sensors using Se etc.
It is something. In this case, a photoelectric conversion element such as CdS-CdSe
One of the children is directly connected to the block by the drive wiring.
The other side of this photoelectric conversion element is directly connected to the read wiring.
If the blocks are in the same position relative to each other,
It will be connected to.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

[0034] Other, may be those with a TFT in place of the blocking diode, it was or not only the contact type image sensor, etc. can also be applied to a full-contact type image sensor, the present invention without departing from the spirit scope It can be implemented in a mode in which various improvements, modifications and variations are added based on the knowledge of those skilled in the art.

Claims (5)

[Claims] 1. A plurality of photoelectric conversion elements are one-dimensionally formed on a substrate, and the photoelectric conversion elements are divided into a plurality of blocks at a constant number, one of the photoelectric conversion elements being a block unit from a drive wiring. An image sensor in which the other of the photoelectric conversion elements are commonly connected to each other by the read wiring at the same position between the blocks, and the drive terminal at the end of the drive wiring is predetermined. An image sensor, characterized in that the image sensor is divided into a plurality of pieces and arranged at a plurality of locations on the substrate. 2. The drive terminal at the end of the drive wiring and the read terminal at the end of the read wiring are arranged on one side of the substrate.
The image sensor described in. 3. The image sensor according to claim 1, wherein a dummy wiring is arranged near at least one of the drive wiring and the read wiring. 4. The read wiring and the lead wiring drawn from the photoelectric conversion element are connected through a plurality of contact holes, and the line width of the read wiring at this connection portion is different from that of the read wiring. 4. The image sensor according to claim 1, wherein the image sensor is wider than the line width in FIG. 5. The image sensor according to claim 1, wherein the image sensor is a contact-type image sensor that reads an original through an erecting equal-magnification lens.