JPH0750743A - Original reader - Google Patents

Abstract

PURPOSE:To prevent the generation of dispersion of original reading output due to the installation state of a conductor wiring group by deciding the width of the conductor wiring composing the conductor wiring group corresponding to the length of the conductor wiring and the wiring space. CONSTITUTION:Each line of a conductor wiring group 200 electrically connecting each light receiving element of a light receiving part 100 and a driving element 300 is installed, for example, at the 4 line/mm intervals corresponding to the resolution of the light receiving part 100. The conductor width of each line is made different according to the length of the line. In short, the conductor width of a line 200S being the shortest line length is widest within the range of the reliable upper limit width and the conductor width of a line 200L being the longer line length is set to be narrow so as not to exceed the lower limit. The conductor width of each line between the lines 200S and 200L is decided so that the line-to-line capacity to be formed by adjacent line conductors should be uniform by taking either line 200S or 200L or a line in the middle as a reference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type document reading apparatus used for reading a document in a facsimile or the like, and particularly electrically connecting a large number of light receiving elements and driving elements for driving these light receiving elements. The present invention relates to improvement of a laying structure of a conductor wiring group.

[0002]

2. Description of the Related Art FIG. 9 shows a general equivalent circuit of the above-mentioned document reading apparatus, and FIG. 9 shows a light receiving section 10 of the apparatus.
A schematic structure of 0 is shown respectively.

That is, the light receiving portion 100 of such an original reading apparatus is provided on an insulating substrate BD made of glass, ceramics, etc., as shown in plan views and sectional views in FIGS. 9 (a) and 9 (b), respectively. For example, the divided electrodes Inl (111, 121, 121, 121, 121) made of a conductive thin film of Al, Cr, Au, etc.
131, 141, ...) and Se-As-Te or a
A photoconductive layer 102 made of an amorphous semiconductor such as -Si or a polycrystalline semiconductor thin film such as CdS or CdSe and a continuous transparent electrode 103 made of a transparent conductive thin film such as SnO ₂ or ITO are sequentially deposited, and The photoconductive layer 102 has a sandwiched structure of two kinds of electrodes, that is, the divided electrode In1 and the transparent electrode 103, which are equivalently equivalent to a photodiode PD and a capacitor C as shown in FIG. It becomes a parallel circuit with.

When one light-receiving element 110 is taken as an example, the capacitor C is assumed to indicate a combined capacity of the capacity of the light-receiving element 110 itself and the capacity of the conductor wiring 210 thereof. Such light receiving elements 110, 120,
... The density required for In0 to resolve the original (for example, 8
A predetermined number of dots / mm) are arranged in the main scanning direction.

Next, the operation of the document reading apparatus will be briefly described with reference to FIG.

In FIG. 9, reference numeral 500 denotes a shift register. When the shift register 500 is driven for the first time, the MOSFETs 310, 320, ... 3n0 are sequentially turned on and off to recharge the capacitor C.
In 00, a current corresponding to the residual charge amount of the capacitor C flows for each bit. This current is output from the output terminal OUT and becomes a read signal of the document reading apparatus. Then, this operation is repeatedly executed every main scanning of the document to be read.

By the way, in this document reading apparatus, when forming the light receiving portion 100, the above-mentioned divided electrode In1 and the photoconductive layer 1 are formed on the same insulating substrate BD.
02 and the transparent electrode 103 can be formed in an array by using a method such as vapor deposition, sputtering, or CVD.
Since 20, ... 3n0 and the shift register 500 are separate elements, at least the respective light receiving elements 110, 120 ,.
In order to electrically connect the In0 and the MOSFETs 310, 320, ... 3n0, it is indispensable to make a connection by wire bonding or the like on the substrate BD or another substrate. Further, for this reason, the light receiving elements 110, 120, ... In0 and the MOSFET 31
The conductor wirings 210, 220, 2n0 for connecting to 0, 320, ... 3n0, respectively, also need to be routed between the two so as to enable the connection by the wire bonding or the like, and as a result, the conductor wiring 210 ，
The length of 220, ..., 2n0 is actually a considerable length.

Therefore, conventionally, in view of such a situation in the manufacture of the contact type document reading apparatus, in laying the conductor wiring group, the above-mentioned light receiving element group and the driving element group such as MOSFET have the shortest distance. So, and the greatest emphasis was placed on ensuring that each was sufficiently reliable conductor width and line spacing. However, when the conductor wiring group is laid in this way, when the number of light receiving elements in charge of the driving element increases or the length of the light receiving element row increases, each of the conductor wiring groups There will be considerable variations in the line capacitance,
The influence of the variation in the line capacitance on the reading of the original document by each light receiving element cannot be ignored.

That is, FIG. 10 shows one of the original reading devices.
9 is a principle diagram of bits (elements having the same functions as those of the circuit elements shown in FIG. 8 are designated by the same reference numerals or symbols as those in FIG. 8), but in general, the storage capacitance C
Is dominated by the line capacitance of the conductor wiring part 200, and if the line capacitance of the conductor wiring part 200 greatly varies for each bit, the read signal level of each light receiving element also becomes uneven, and the original Even if one scan target line is all white (or all black) like the reference white part of
The read output of the document reading device becomes unstable as shown in FIG. 11, for example. Therefore, in the conventional document reading apparatus, it is indispensable to correct the above-mentioned output unevenness by using an appropriate level correction circuit.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to prevent the occurrence of variations in document reading output due to the laying mode of conductor wiring groups.

[0011]

Therefore, in the present invention, the conductor wiring portion is generally a thin film or a thick film of at most several μm.
Since it is laid as a conductor layer with a certain thickness, pay attention to the fact that the inter-line capacitance due to the presence of conductors on the same plane is more dominant than the capacitance on the opposite plane as the inter-line capacitance. It was done.

In the first aspect of the present invention, a plurality of light receiving elements arranged in the main scanning direction of the original on the substrate, driving elements for driving these light receiving elements, and these light receiving elements and driving elements are electrically connected. In a charge storage type document reading apparatus including a conductor wiring group for connection, the width of the conductor wiring forming the conductor wiring group is determined in correspondence with the length of the conductor wiring and the wiring interval. It is characterized by

In the second aspect of the present invention, each conductor line is provided with a capacitance correcting conductor having a shape and an area corresponding to the wiring position.

In the third aspect of the present invention, the line lengths of the conductor lines are all made uniform.

[0015]

According to the first aspect of the present invention, the width of the conductor wirings forming the conductor wiring group is not limited to the method of simply keeping the area of the wiring itself constant, but the line-to-line capacitance with the peripheral wiring also greatly contributes. Paying attention to the fact that
As shown in (2) to (2), it is determined corresponding to the length of the conductor wiring and the wiring distance in consideration of the wiring distance between the wiring and the surrounding wiring. Further, in the second aspect of the present invention, since the capacitance is corrected by the capacitance correcting conductor, it is possible to make the capacitance uniform with extremely high accuracy.

With this structure, the line capacitance due to the presence of the conductors on the same plane is substantially uniform, so that the storage capacitance generated between each of the light receiving elements and the driving element is the same. All the bits have substantially the same capacity, and the read signal level of each light receiving element does not vary due to the same storage capacity.

The area of the capacitance compensating conductor is not necessarily configured to be constant together with the wiring conductor, but the capacitance between itself and the line capacitance between the capacitance compensating conductor and the wiring conductor, etc. In consideration of the above, the line capacitance is determined to be substantially constant at each position.

Further, in the third aspect of the present invention, since the length of each conductor line is made uniform, the substantial length is made uniform by arranging the wiring, and the line capacitance becomes constant. In this way, variations in read signal level can be suppressed.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the position of a document reading apparatus of the present invention. However, in FIG. 1 as well, elements having the same functions as those of the elements of the prior art shown in FIGS. 8 to 10 are denoted by the same reference numerals, and redundant description will be omitted.

In this embodiment, one driving element 300 is assigned to, for example, 128 light receiving elements, and a plurality of blocks are arranged in parallel. Particularly, in this embodiment,
Each line of the conductor wiring group 200 that electrically connects each light receiving element of the light receiving unit 100 and the drive element 300,
Corresponding to the resolution of the light receiving unit 100, for example, 4 lines / mm
Assuming that the conductors are laid at equal intervals, the conductor width of each of the lines is made different according to the line length determined by the wiring position so that the line-to-line capacitance of the conductor line group 200 becomes substantially uniform. I have to.

Specifically, as shown in FIG. 1, as a result, the conductor width of the line 200s having the shortest line length is the widest and the longest line length 200L to the extent that the reliable upper limit width is not exceeded. The conductor width is set to the smallest value that does not exceed the reliable lower limit width, and the conductor width of each line between them is based on one of the above lines or any one line in between. As a result, it is determined empirically or by calculation so that the inter-line capacitance formed by the adjacent line conductors becomes uniform.

A method of manufacturing the device of the embodiment, that is, a method of determining the conductor width of each line in the conductor wiring group 200 will be described below in detail with reference to FIGS.

Assuming that the conductor wirings of interest are wirings 210 and 220 as shown in FIGS. 2 and 3, first, a method of calculating the line capacitance between these wirings 210 and 220 will be described.

As shown in FIG. 3, the distance between the wirings 210 and 220 is S, the conductor width is W, and the thickness of the insulating substrate BD is D. Further, the relative permittivity of the substrate BD is ε _s . Further, since the conductor thickness H of the wirings 210 and 220 is a very small value as described above, this is ignored, and all the lines of electric force on the side of the board BD are the same as those of the board B.
Assuming that the wiring runs through D, the above wirings 210 and 220
The capacity C per unit length between is given by the following equation.

[0025] However, Also, Therefore, if the conductor wiring length of interest is L (cm) as shown in FIG. 2, the obtained line capacitance C is as follows.

[0026] The above values K ₁ , K ₁ ′, K ₂ and K ₂ ′ are perfect elliptic integrals.

Since the line capacitance C is obtained in this manner, conversely, it is possible to calculate and determine the conductor width W of each wiring in order to make the capacitance C uniform. When actually manufacturing the device of the same embodiment, In order that the conductor width W does not exceed the upper limit width and the lower limit width for making the reading operation of the apparatus sufficiently stable as described above, for example, based on a program as shown in FIG.
The conductor width W is decided at any time.

That is, the value (actually, the value of the storage capacitor C (see FIG. 8 or 9) suitable for obtaining a read signal of a required level from the output terminal (corresponding to the terminal OUT shown in FIG. 8) of the device. As described above, the line capacitance of the conductor wiring group 200 is dominant, and here, for convenience, the value of this line capacitance is set as the value of the total storage capacitance C) in advance (step 1100). First, the conductor width W of the wiring of interest is determined (step 1110), and the line-to-line capacitance with the adjacent conductor wiring (this is referred to as C'for convenience) is calculated based on the above equation (2) (step 1130). . As a result, the value of the capacity C previously determined and the calculated capacity C
The value of the conductor width W is changed so that the conductor width becomes equal to the value of ‘′ (step 1200), and the value of the capacitance C and the value of capacitance C ′ become equal to each other. The value of the conductor width W is re-determined so that
0). When the determined value of the conductor width W does not fall within the range of the upper limit width and the lower limit width described above (step 1
120), the previously set value of the capacitance C is changed (step 1300), and the same conductor width W is decided again.

By carrying out the conductor width determination work of each wiring based on such a program for all the conductor wirings constituting the conductor wiring group 200, each line capacitance, that is, the storage capacitance C shown in FIG. 8 or FIG. The values are uniform for all the light receiving elements, and the read output of the same device is stable as shown in FIG. 5 for pixels of the same density such as all white and all black.

In the above embodiment, the conductor widths of the conductor wirings laid with the same number of wirings per unit width of the substrate are changed according to the wiring positions so that the line capacitances are substantially uniform. However, as shown in FIG.
As shown in Fig.4, make the conductor line length uniform without changing the conductor width (the wiring in the portion where the distance between the light receiving element and the driving element is short is adjusted by meandering appropriately), or As shown in FIG. 7, a dummy conductor DM for adjusting the line capacitance may be provided to make each line capacitance substantially uniform. In any of these cases, the equation (2) can be used to calculate the line capacitance.

[0031]

As described above, according to the document reading apparatus of the present invention, it is possible to obtain a read output and it is not necessary to separately provide the level correction circuit as described above. It is also advantageous in terms of cost.

[Brief description of drawings]

FIG. 1 is a plan view showing a laying structure of a conductor wiring group according to an embodiment of the present invention.

FIG. 2 is a schematic diagram schematically showing a part of another conductor wiring group for calculating the line capacitances of the conductor wiring group.

FIG. 3 is a schematic diagram schematically showing a part of another conductor wiring group for calculating the line capacitance of each conductor wiring group.

FIG. 4 is a flowchart showing a method for determining the conductor width of each line in this conductor wiring group;

5 is a diagram showing output characteristics of the device of the embodiment shown in FIG.

FIG. 6 is a plan view showing the laying structure of a conductor wiring group of another embodiment of the document reading apparatus of the present invention,

FIG. 7 is a plan view showing the laying structure of a conductor wiring group of another embodiment of the document reading apparatus of the invention.

FIG. 8 is a circuit diagram showing a general equivalent circuit of a document reading device of the present invention,

FIG. 9 is a diagram schematically showing a light receiving portion structure of the document reading apparatus,

FIG. 10 is a diagram showing a theoretical equivalent circuit for 1 bit of the document reading apparatus;

FIG. 11 is a diagram showing output characteristics of a conventional document reading apparatus.

[Explanation of symbols]

 100 light receiving part, 200 conductor wiring group, 300 driving element, 400 driving wiring group, 500 shift register, 600 read signal output line, 700 bias voltage supply line

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[Procedure amendment]

[Submission date] January 25, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

In the second aspect of the present invention, a capacitance correcting conductor having a shape and an area corresponding to the wiring length is connected to each conductor line.

Claims (3)

[Claims] 1. A plurality of light receiving elements arranged on a substrate in the main scanning direction of a document, a driving element for driving these light receiving elements, and a conductor for electrically connecting these light receiving elements and the driving elements. In a charge storage type document reading apparatus including a wiring group, the width of the conductor wiring forming the conductor wiring group is determined in correspondence with the length of the conductor wiring and the wiring interval. Document reader. 2. A plurality of light receiving elements arranged on a substrate in the main scanning direction of an original, driving elements for driving these light receiving elements, and conductors for electrically connecting these light receiving elements and the driving elements. In a charge storage type document reading apparatus including a wiring group, at least one conductor wiring of the conductor wiring group is connected to a capacitance correction conductor determined according to the length of the wiring. Document reading device. 3. A plurality of light receiving elements arranged on a substrate in the main scanning direction of a document, driving elements for driving these light receiving elements, and conductors for electrically connecting these light receiving elements and the driving elements. A charge accumulating document reading device including a wiring group, wherein the conductor wiring lengths of the conductor wiring group are configured to be substantially equal to each other.