JPH06303393A - Picture reading method and device therefor - Google Patents

Abstract

PURPOSE:To provide an efficiently inexpensive picture reader by reducing driving gates. CONSTITUTION:In the picture reader for dividing plural photoelectric conversion elements 10 and 12 into (n) pieces of first blocks B1, B2,...Bn every (m) pieces of the blocks and reading electric signals in the unit of (m) pieces of the photoelectric conversion elements 10 and 12, the driving side of (n) pieces of the first blocks are further divided into (y) pieces of second blocks C1, C2,...Cy at every (x) pieces of block. A first impressing means impresses first driving voltages (D1, D2,...Dy) in an order in the unit of (x) pieces of the first blocks B1, B2,...Bx in the second block and also a second impressing means impresses second driving voltages (E1, E2,...Ex) in the order in the unit of the first blocks B1, B2,...Bx present at relatively same positions among the respective second blocks. Then, when the first driving voltage (D1) and the second driving voltage (E1) are simultaneously impressed to the first blocks B1, B2,...Bn, driving is performed in the unit of (m) pieces of the photoelectric conversion elements 10 and 12 within the first blocks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading method and an apparatus therefor, and more particularly, to a method and an apparatus for reading an image on an original such as a facsimile, an image scanner, a digital copying machine, an electronic blackboard in a time series. Regarding improvement.

[0002]

2. Description of the Related Art In recent years, a charge coupled device (CC) has been used in a document reading unit such as a facsimile.
An image reading apparatus generally called a contact image sensor is used instead of the image reading apparatus of the reduction optical system using D). This image reading apparatus has a plurality of one-dimensionally formed photoelectric conversion elements made of a thin film semiconductor such as amorphous silicon a-Si on a glass substrate, and can read an image on a document at the same size. A photodiode is usually used as the photoelectric conversion element, but since the photocurrent generated in the photodiode is extremely weak, the charge storage method in which this photocurrent is temporarily stored in the junction capacitance of the photodiode and then detected is widely adopted. ing. Further, since the number of photoelectric conversion elements is very large, a matrix driving method which usually requires a small number of switching elements is adopted.

Here, an example of the image reading apparatus of the matrix drive system by the charge storage method will be briefly described with reference to the drawings.

As shown in FIG. 8, in a conventional image reading apparatus, m × n photodiodes 1 as photoelectric conversion elements are arrayed, and a blocking diode 2 is connected in series to these photodiodes 1 with opposite polarities. There is. These photodiodes 1 and blocking diodes 2 are divided into n blocks B _1, B _2, ... B _n every m. The anode terminal of the blocking diode 2 is a buffer gate 3 common to each block B _1, B _{2, ...} B _n.
Is connected to each output terminal of the shift register 4.

On the other hand, the anode terminal of the photodiode 1 is located at a relatively same position among the blocks B _1, B _{2, ...} B _n , and the common current amplifying circuits IV _1, IV _{2 ,.} I
It is connected to the integration circuits IN _1, IN _{2, ...} IN _m via V _m . Further, sample-hold circuits SH _1, SH _{2, ...} SH _m , a multiplexer circuit MPX and an amplification circuit 5 are connected to the integration circuits IN _1, IN _{2, ...} IN _m , and these current amplification circuits are connected. IV _1, IV _{2, ...} IV _m , integration circuits IN _1, IN _{2, ...} IN _m , sample hold circuits SH _1, SH _{2, ...} SH _m , and multiplexer circuit MP
A signal processing circuit for time-integrating the currents I _1, I _{2, ...} I _m flowing out from the photodiode PD is constituted by X and the amplifier circuit 5.

According to this image reading apparatus, as shown in the time chart of FIG. 9, the data input pulse Din input to the shift register 4 sequentially shifts in the shift register 4 in accordance with the clock pulse CLK, The signals are sequentially output from the respective output terminals. As a result, the drive voltage is sequentially applied to each photodiode 1 in units of blocks B _1, B _{2, ...} B _n . In the photodiode 1 to which the drive voltage is applied, currents I _1, I _{2, ...} I _m corresponding to the optical signals accumulated in the junction capacitance flow, and the current amplification circuits IV _1, IV _{2 are} generated. _{, ...} IV _m , and further integrated circuits IN _1, IN _{2, ...} IN _m , sample hold circuits SH _1, SH _{2, ...} SH _m , multiplexer circuit MPX, and amplification circuit 5 Current I _1, I flowing out from the photodiode PD by the signal processing circuit including
_{2, ...} I _m are subjected to signal processing to obtain an output voltage Vout. In this way, the electric signal of each photodiode 1 is transferred to the blocks B _1, B _{2, ...} B by the shift register 4 and the like _.
The channels are sequentially scanned in units of _n , and the channels for one block are read out at the same time.

[0007]

As described above,
Drive voltage Vd of matrix drive method by charge storage method
Is a shift register output as shown in the time chart. For this reason, the number of elements is 1728 in an A4 size image reading apparatus of 8 elements / mm.
It is composed of either 32 channels x 54 blocks, 16 channels x 108 blocks or 8 channels x 216 blocks, usually 16 channels x
It is composed of 108 blocks. However, there is a problem that a large number of shift registers are required in any structure. Further, when integrated into an IC, the analog circuit section is expensive, so it is necessary to use many inexpensive digital circuits.

Therefore, the inventors of the present invention have conducted extensive studies to reduce the number of drive gates and provide an efficient and inexpensive image reading apparatus, and as a result, the present invention has been achieved.

[0009]

The gist of the image reading method according to the present invention is to apply a driving voltage to a plurality of one-dimensionally arranged photoelectric conversion elements in order to obtain an electric signal of the photoelectric conversion elements. In the image reading method for reading out, the driving side for applying a driving voltage to the photoelectric conversion element is divided into y blocks for each x, and the driving voltage is applied in a matrix of x × y. Is to drive.

Another aspect of the image reading method according to the present invention is that a driving voltage is sequentially applied to a plurality of one-dimensionally arranged photoelectric conversion elements to read an electric signal of the photoelectric conversion elements. In the image reading method, a driving side that applies a driving voltage to the photoelectric conversion element is divided into y blocks for each x, and the first driving voltage is sequentially set for each x photoelectric conversion element in the block. And a second drive voltage is sequentially applied in units of photoelectric conversion elements located at the same relative position between the blocks, and the first drive voltage and the second drive voltage are applied.
That is, the photoelectric conversion element can be driven when the driving voltage and the driving voltage are simultaneously applied.

Another aspect of the image reading method according to the present invention is that a plurality of one-dimensionally arranged photoelectric conversion elements are divided into n first blocks every m, and the photoelectric conversion elements are divided into n first blocks. In an image reading method of sequentially applying a driving voltage in units of m photoelectric conversion elements in the first block to read out an electric signal of the photoelectric conversion elements, the driving voltage is applied to the n divided first blocks. The driving side to be sequentially applied is further divided into y second blocks for each x, and the first driving voltage is sequentially applied in units of x first blocks in the first second block. , The second drive voltage is sequentially applied in units of the first blocks that are relatively in the same position between the second blocks, and the first drive voltage and the second drive voltage are simultaneously applied to the first block. When applied, the m photoelectric conversion elements in the first block are Position to in that so as to drive.

On the other hand, the gist of the image reading apparatus according to the present invention is that an image in which a driving voltage is sequentially applied to a plurality of one-dimensionally arranged photoelectric conversion elements and an electric signal of the photoelectric conversion elements is read out. In the reading device, the driving side for applying a driving voltage to the photoelectric conversion element is divided into y blocks for each x, and the first driving voltage is sequentially applied in units of x photoelectric conversion elements in the block. First applying means for applying, second applying means for sequentially applying a second drive voltage in units of photoelectric conversion elements located at the same relative position between the blocks, and the first drive voltage And a matrix drive section for applying a drive voltage for driving the photoelectric conversion element when the second drive voltage is applied at the same time.

Another feature of the image reading apparatus according to the present invention is that a plurality of one-dimensionally arranged photoelectric conversion elements are divided into n first blocks every m. In an image reading apparatus in which a driving voltage is sequentially applied in units of m photoelectric conversion elements in the first block and an electric signal of the photoelectric conversion elements is read, a driving voltage is applied to the n divided first blocks. Is sequentially divided into y second blocks for each x, and the first drive voltage is sequentially applied in units of x first blocks in the first second block. A first application unit, a second application unit that sequentially applies a second drive voltage in units of the first blocks that are relatively in the same position between the second blocks, and the first drive voltage. When the second driving voltage is applied to the first block at the same time, It is to have a matrix driver for applying a driving voltage for driving the m-number of photoelectric conversion elements in the block units.

In such an image reading apparatus, the matrix drive section is composed of an adder circuit composed of resistors.

Further, in the image reading apparatus, the matrix driving section is composed of an AND circuit.

[0016]

According to such an image reading method and apparatus, the side for applying a driving voltage to the photoelectric conversion element is formed into a matrix of x × y, and each photoelectric conversion element or a plurality of blocked photoelectric conversion elements are used as a unit. The driving voltage is sequentially applied.

That is, the drive side for applying the drive voltage to the photoelectric conversion element is divided into y blocks for each x, and the first drive voltage is applied in order for each photoelectric conversion element in the block. , The second drive voltage is sequentially applied in units of photoelectric conversion elements located at the same relative position between the blocks, and both the first drive voltage and the second drive voltage are simultaneously applied by the matrix drive section. When it is turned on, the corresponding photoelectric conversion element is driven. Therefore, when the first drive voltage and the second drive voltage are sequentially applied by the matrixed applying means, the photoelectric conversion elements are driven in order.

Further, a plurality of one-dimensionally arranged photoelectric conversion elements are divided into n first blocks every m, and the driving voltage is sequentially set in units of the m photoelectric conversion elements in the first block. In the image reading apparatus in which the electric signal of the photoelectric conversion element is read by being applied, similarly to the above, the driving side to which the driving voltage is sequentially applied is further divided into y second blocks every x. It is configured to drive m photoelectric conversion elements in one block as a unit. Therefore, the first driving voltage and the second driving voltage are sequentially applied by the matrixed applying unit, so that the first driving voltage and the second driving voltage are sequentially applied.
The m photoelectric conversion elements in the block can be sequentially driven as a unit.

[0019]

Embodiments of the image reading method and apparatus according to the present invention will now be described in detail with reference to the drawings.

As shown in FIG. 1, in the image reading apparatus according to the present invention, m × n photodiodes 10 as photoelectric conversion elements and a blocking diode 12 connected in series to them in reverse polarity are primary. Originally arranged, m
One photodiode 10 and blocking diode 1
N and the first blocks B _1, B _{2, ...} B with ₂ as one unit
_It is divided into _n . The photodiode 10 and the blocking diode 12 are made of amorphous silicon.
Thin-film semiconductors such as a-Si are formed by stacking at the same time in a pin structure or the like, and may have the same structure or different structures.

The respective anode terminals of these photodiodes 10 which are at the same relative position between the first blocks B _1, B _{2, ...} B _n are common to the matrix wiring 1
4 is connected. In addition, these matrix wiring 1
A current amplification circuit, an integration circuit, a sample hold circuit, a multiplexer circuit, etc. are normally connected to the output terminal of 4, and the currents I _1, I _{2, ...}
I _m is time-integrated and serially output.

On the other hand, each anode terminal of the blocking diode 12 is connected to a common wiring 16 common to each of the first blocks B _1, B _{2, ...} B _n , and further divided into n pieces. One block B _1, B _{2, ...} B _n is divided into y second blocks C _1, C _{2, ...} C _y for each x. Then, each of the second blocks _{C 1, C 2, ... C} y respectively in the x
Number of first blocks B _1, B _{2, ...} first in sequence B _x in the unit
So that the drive voltage of the first block B _1, B
The common wiring 16 of _{2, ...} B _x is connected to the common input terminals D _1, D _{2, ...} D _y via resistors Rd.
Further, each of the second blocks C _1, C _{2, ...} C first block B ₁ is in the same relative position between _y, B _{2, ...} through each common wiring 16 is resistance Re of B _x Common input terminal E
_1, E _{2, ...} are connected to the E _x, the second driving voltage second block C _1, C _{2, ...} first block B ₁ in C _y, B _{2, ...} B
It is configured so that _x can be applied individually and sequentially.

Here, arbitrary first blocks B _1, B _{2, ...}
As shown in FIG. 2, a resistor Rd and a resistor Re are connected to an arbitrary pair of the photodiode 10 and the blocking diode 12 in B _n , thereby forming an adder circuit. Therefore, the first drive voltage D = 5V and the second drive voltage E = 5V from the input terminals D _(y) and E _(x) , respectively.
Is input, the potential Vd at the point B is 5 V, and the read state is set. Next, when the first drive voltage D = 0 V and the second drive voltage E = 0 V, the potential Vd at the point B is 0 V, and D = 0 V, E = 5 V or D = 5 V, E = 0V
Is input, the potential Vd at point B is 2.5V,
Both are in the storage state and are not read.

By the way, when the potential Vd at the point B is 2.5V and the potential V _PD between the photodiode 10 and the blocking diode 12 does not drop below 2.5V, no problem will occur. . Further, if the light incident on the photodiode 10 is too strong, it will be read even if the potential V _PD is 2.5V. However, even in this case, reading can be avoided by shortening the accumulation time, that is, by increasing the speed.

The input terminals _{D 1, D 2, ... D} y and input terminals E _1, E _{2, ...} each output terminal of the shift register via buffer gates, not shown, respectively is connected to the E _x However, these constitute the first applying means and the second applying means, respectively. Therefore, the shift register used has a total of (x + y) stages of flip-flops, which is significantly larger than that of a conventional shift register having n (= x × y) stages of flip-flops. The number can be reduced.

In such an embodiment, the resistor R used
d and Re are input terminals D _1, D _{2, ...} D _y and input terminals E _1,
Corresponding to the number of E _{2, ...} E _x , the resistance Rd is y and the resistance R is
e is x and resistance is Rd = Re = R, the first or second
If the drive voltage of V is V, the consumption current is (y-1) / 2R × V on the input terminal D _(y) side and (x-1) / 2R × V on the input terminal E _(x) side. . So, for example, 8
ch analog (220 blocks) y = 10, x = 22
With a matrix of Rd = Re = R = 10
If KΩ and the first or second drive voltage is V = 5v, the current consumption on the input terminal E _(x) side is 5.25 mA, the input terminal D
_The current consumption on the _(y) side is 2.25 mA. Therefore, the resistors Rd and Re to be used are determined in reverse from this, and several KΩ ~
Several tens of KΩ is preferable.

Next, the operation of this image reading apparatus will be described with reference to FIG.
The image reading device 18 in which the driving side shown in (a) is formed into a matrix of 3 × 3 will be described as an example with reference to the time chart shown in FIG. The image reading device 18 is a simplified version of the image reading device shown in FIG. 1 and has the same configuration, so the description thereof will be omitted.

Input terminals D1, D2, D3 and input terminal E which constitute the first and second applying means of the image reading device 18
1, E2 and E3 are connected to the output terminals of the shift register via the buffer gates respectively, and the data input pulse input to this shift register is sequentially shifted in the shift register in accordance with the clock pulse CLK. The signals are sequentially output from each output terminal of the shift register.

That is, the first drive voltage sequentially input from the input terminals D1, D2, D3 is passed through the resistor Rd to the first blocks B1, B2, B3, the first blocks B4, B5, B6 and the first blocks B1, B2, B6, respectively. The photoelectric conversion elements of one block B7, B8, B9 are applied. Here, the timing of sequentially inputting the first drive voltage is such that the rising edge and the falling edge coincide. On the other hand, the second drive voltage sequentially input from the input terminals E1, E2, E3 is passed through the resistor Re to the first blocks B1, B4, B7 and the first block B, respectively.
2, B5, B8 and the photoelectric conversion elements of the first blocks B3, B6, B9 are applied. Here, the timing of sequentially inputting the second drive voltage is such that the rising edge and the falling edge coincide.

As a result, the first drive voltage sequentially input from the input terminals D1, D2, D3 and the input terminals E1, E
The second drive voltage sequentially input from E2 and E3 are added by an adder circuit including resistors Rd and Re, respectively, and when a predetermined applied voltage is reached, the first block B
The photoelectric conversion elements 1, B1 ... B9 are driven. Therefore, for example, when the first drive voltage is input from the input terminal D1, the input terminals E1, E
By shifting and applying the second drive voltage in order from 2, E3, the photoelectric conversion elements in the first blocks B1, B2, B3 are driven in order. Similarly, when the first drive voltage is input from the input terminal D2, the second drive voltage is sequentially applied from the input terminals E1, E2, and E3 by shifting and applying the first drive voltage.
The photoelectric conversion elements in the blocks B4, B5, B6 are driven in order.

The image reading device 18 is driven in this manner. As described above, the rising and falling of the image reading device 18 are made coincident with each other at the timings of the first and second driving voltages, and the resistances of the resistors Rd and Re are changed. When the values are made to coincide with each other, the change in the applied voltage between the first blocks B1 and B2, B2 and B3, etc. is shown in the lower part of Table 1 when sequentially shifting from T1 to T2 and from T2 to T3. It becomes as shown in. As a result, the first blocks B1, B1 ... B
The total change in applied voltage for each 9 is 0, that is, it is canceled between blocks, and noise is not output.

[Table 1]

The embodiment of the image reading method according to the present invention and the apparatus used directly for carrying out the method have been described above in detail. However, the present invention is not limited to the above-described embodiment and can be carried out in other modes. I will get it.

For example, as shown in FIG. 4, the image reading apparatus 20 includes m × n photodiodes 10 as photoelectric conversion elements and blocking diodes connected in series to them in reverse polarity, as in the above-described embodiment. 12 and 12 are arranged one-dimensionally. Then, these photodiodes 10
The anode terminals of the above are relatively similar in position among the first blocks B _1, B _{2, ...} B _n , and are connected to the common matrix wiring 14 to have the same configuration.

On the other hand, each anode terminal of the blocking diode 12 has the same first block B _1, B 2 as described above.
The first blocks B _1, B _{2, ...} Connected to the common wiring 16 common to each of the _{2, ...} B _n and further divided into n blocks _.
B _n is divided into y second blocks C _1, C _{2, ...} C _y for each x. Then, each second block C _1, C _{2, ...}
Each of the x first blocks B _1, B _{2, ...} B _{x in} C _y
The common wiring 16 of the first blocks B _1, B _{2, ...} B _x is respectively connected to the common input terminals D _1, D via the diodes Did so that the first drive voltage can be sequentially applied in units of. _{2, ...}
Connected to D _y . Further, each second block C _1, C
First block B located at the same relative position between _{2, ...} C _y
Common wiring 16 of _1, B _{2, ...} B _x is diode D
input terminals in common via ie E _1, E _{2, ...} are connected to the E _x, the second driving voltage second block C _1, C _{2, ...} first block B ₁ in C _{y ,} B _{2, ...} B _x can be applied individually and sequentially. The anode terminals of the diodes Did and Die are connected in series to the anode terminal of the blocking diode 12, and the bias voltage Va is applied to the anode terminal side via the resistor R.

Here, arbitrary first blocks B _1, B _{2, ...}
As shown in FIG. 5, a diode Did and a diode Die are connected to an arbitrary pair of photodiode 10 and blocking diode 12 in B _n , and
A bias voltage Va = 5V is applied through the resistor R, and an AND circuit including diodes is configured. Therefore, when the forward voltage V _F ≈0 V, an ideal output is produced, and the first driving voltage D = 5 V and the second driving voltage E = 5 V are input from the input terminals D _(y) and E _(x) , respectively. When input, the potential Vd at the point B is 5 V, and the read state is set. Next, the first drive voltage D = 0V and the second drive voltage E
= 0V, the potential Vd at the point B is 0V, and when D = 0V, E = 5V, or D = 5V, E = 0V, the potential Vd at the point B is 0V. , Both are in the storage state and are not read.

When the forward voltage V _F = 1 V, the first driving voltage D = from the input terminals D _(y) and E _(x) respectively.
When 5V and the second drive voltage E = 5V are input, the potential Vd at the point B is 5V, and the read state is set. Then the first
When the driving voltage D = 0V and the second driving voltage E = 0V, the potential Vd at the point B is 0.5V, and D = 0V,
When E = 5V or D = 5V, E = 0V is input,
The potential Vd at the point B becomes 1V. Therefore, in this case, if the potential V _PD between the photodiode 10 and the blocking diode 12 does not drop below 1 V, the storage state is maintained and reading is not performed.

Next, the operation of this image reading apparatus will be described with reference to FIG.
An example of the image reading device 22 in which the driving side shown in (a) is formed into a matrix of 3 × 3 will be described with reference to the time chart shown in FIG. The image reading device 22 is a simplification of the image reading device 20 shown in FIG. 1 described above, and since the configuration is the same, the description thereof will be omitted.

Input terminals D1, D2, D3 and input terminal E constituting the first and second applying means of the image reading device 22.
1, E2 and E3 are connected to the output terminals of the shift register via the buffer gates respectively, and the data input pulse input to this shift register is sequentially shifted in the shift register in accordance with the clock pulse CLK. The signals are sequentially output from each output terminal of the shift register. That is, the first drive voltages sequentially input from the input terminals D1, D2, D3 are the first block B, respectively.
1, B2, B3 and the diodes Did of the first blocks B4, B5, B6 and the first blocks B7, B8, B9 are applied. Here, the timing of sequentially inputting the first drive voltage is such that the rising edge and the falling edge coincide. On the other hand, the second drive voltages sequentially input from the input terminals E1, E2, E3 are the first blocks B1, B4, B7,
First block B2, B5, B8 and first block B3
The diodes D6 of B6 and B9 are applied. Where the second
As for the timing of sequentially inputting the drive voltage of, the rising edge and the falling edge are matched.

As a result, the first drive voltage sequentially input from the input terminals D1, D2, D3 and the input terminals E1, E
The second drive voltage sequentially input from E2 and E3 is composed of a diode Did and a diode Die, respectively.
When they match in the circuit, the applied voltage is output and the photoelectric conversion elements of the first blocks B1, B1 ... B9 are driven. Therefore, for example, the input terminal D1
From the input terminals E1, E2, and E3 while sequentially applying the first drive voltage from the first block B1 to the first block B1 by applying the second drive voltage.
The photoelectric conversion elements in 2 and B3 are driven in order. Similarly, when the first drive voltage is input from the input terminal D2, the input terminals E1, E2, E
By shifting and applying the second drive voltage in order from 3, the photoelectric conversion elements in the first blocks B4, B5, B6 are sequentially driven.

The image reading device 22 is driven in this manner. As described above, the rising and falling edges of the image reading device 22 are made to coincide with each other at the timings of the first and second driving voltages, and the diodes Did, Die are also used. By matching the values of the forward voltage V _F at
When changing from T2 to T3 in order, the changes in the applied voltage between the first blocks B1 and B2, B2 and B3, etc. are as shown in the lower part of Table 2. as a result,
The sum of the changes in the applied voltage for each of the first blocks B1, B1 ... B9 is 0, that is, they are canceled out between the blocks, and noise is not output.

[Table 2]

Next, the image reading method and the apparatus therefor according to the present invention, as shown in the above-mentioned embodiment, are provided with the photodiode 1
The photoelectric conversion element composed of 0 and the blocking diode 12 is divided into a plurality of blocks for every fixed number and is not limited to a multi-channel type, and the channel can be set according to the response of the sensor.

For example, as shown in FIG. 7 (a), the image reading device 24 can be constructed by one channel.
That is, in the photoelectric conversion element including the pair of photodiodes 10 and the blocking diodes 12, all the anode sides of the photodiodes 10 are connected by the common wiring 26 and output through the current amplifier circuit 28. On the other hand, on the anode side of the blocking diode 12, two resistors R of the same value are connected in parallel to form an adder circuit, and a fixed x photoelectric conversion elements are used as a unit for y blocks B _1, B _2, divided into _... B _y, block B _1, B
_{2, ...} B one of the resistor R is input D ₁ which is common in the _y, D
_{2, ...} Connected to D _y . Furthermore, among the _y blocks B _1, B _{2, ... By} , the other resistors R corresponding to the photoelectric conversion elements at the same relative positions are connected to the input terminals E _1, E 2.
_2, and it is configured by connecting to _... E _x.

[0043] As such an image reading apparatus 24 shows a time chart in FIG. (B), the input terminal D _1, D _{2, ...} first driving voltage from _{D y D1, D2, ......,} Dy is is shifted into order, whereas, the input terminal E _1, E _{2, ...} second driving voltage from _{E x E1, E2, ......,} Ex is input is shifted sequentially. Therefore, the first drive voltage D
1, D2, ..., Dy and the second drive voltages E1, E2 ,.
, Ex are added to drive the photoelectric conversion elements that have reached a predetermined applied voltage, and as shown in the time chart, the photoelectric conversion elements including the photodiode 10 and the blocking diode 12 are driven in order. Read and read.

In this embodiment, the matrix driving section is composed of a resistance adding circuit, but it is also possible to adopt the same circuit structure as the above by an AND circuit of a diode. In any configuration, the output system from the anode terminal of the photodiode 10 is one column, the current amplifier circuit and the like may be one system, and only the digital part is provided, so that a cheaper image reading device is provided. be able to.

Next, in the above-described embodiment, the photodiode 1 is used.
0 and the cathode terminals of the blocking diode 12 are connected to each other. Conversely, the anode terminals of the photodiode 10 and the blocking diode 12 are connected to each other, and the cathode terminal of the photodiode 10 is connected to a resistor or an AND which constitutes an addition circuit. It is also possible to connect the anode terminal of a diode forming the circuit and connect the cathode terminal of the blocking diode 12 to the current amplification circuit.
Further, the present invention can be applied not only to the blocking diode 12 but also to a type that is selectively driven by a TFT or the like. Further, not only the contact type but also a so-called perfect contact type image reading apparatus can be applied. is there.

Further, although the above-mentioned diode AND circuit which is the matrix drive section is constituted by the positive logic type AND circuit, it may be constituted by the negative logic type AND circuit in which the polarities of the diode and the bias power supply are reversed. Is. Further, the AND circuit is most preferably a diode, but it goes without saying that an AND circuit having another configuration may be used.

Here, the diodes forming the AND circuit are the photodiode 10 and the blocking diode 1.
It is most preferable to use the amorphous semiconductor or the crystalline semiconductor that composes 2. Also, adder circuit and AN
For the resistor that constitutes the D circuit, a resistor is separately deposited,
It may be formed by wire bonding or the like, or may be formed by utilizing a portion of the semiconductor layer which is a relatively good conductor.

Next, as described above, the image reading method and apparatus according to the present invention resides in that the driving side of the photoelectric conversion element is formed into a matrix and driven, and various methods are added to the method and apparatus. It is possible to

For example, in the image reading method of sequentially applying a driving voltage to a plurality of one-dimensionally arranged photoelectric conversion elements according to the same configuration as the present invention to read the electric signal of the photoelectric conversion elements, the photoelectric conversion is performed. Before applying the driving voltage to the device, the driving voltage may be sequentially applied to a plurality of pseudo photoelectric conversion devices having substantially the same characteristics as the photoelectric conversion device, so that it is repeated twice or more.

According to such an image reading method, the drive voltage is sequentially applied to the plurality of pseudo photoelectric conversion elements before the drive voltage is applied to the regular photoelectric conversion elements, and these pseudo photoelectric conversion elements are further applied once or more. A drive voltage is sequentially applied to the photoelectric conversion elements. That is, the drive voltage is applied to the pseudo photoelectric conversion element several times between the application of the drive voltage to the first pseudo photoelectric conversion element and the application of the drive voltage to the first photoelectric conversion element. Therefore, the capacitance kick generated when the driving voltage is applied to the first pseudo photoelectric conversion element is sufficiently eliminated during this period. As a result, the electric signal containing only the signal component is read from the photoelectric conversion element. Moreover, since the drive voltage is repeatedly applied to the same plurality of pseudo photoelectric conversion elements, the number of pseudo photoelectric conversion elements required to eliminate the capacitance kick that occurs first can be relatively small.

Further, in the image reading apparatus according to the same configuration as the present invention, in which a driving voltage is sequentially applied to a plurality of one-dimensionally arranged photoelectric conversion elements to read out an electric signal of the photoelectric conversion elements, A plurality of pseudo photoelectric conversion elements having almost the same characteristics as the conversion element are provided, and the driving voltage is sequentially applied to the pseudo photoelectric conversion elements two or more times before the driving voltage is applied to the photoelectric conversion elements. It may be configured by providing initialization means.

Such an image reading apparatus implements the above-mentioned image reading method. In this case, the initializing means repeatedly applies the driving voltage to the pseudo photoelectric conversion elements in order, and the capacitance generated first is increased. The kick will be completely eliminated. Further, since the driving voltage is repeatedly applied to the same plurality of pseudo photoelectric conversion elements,
The number of pseudo photoelectric conversion elements is relatively small.

Furthermore, in the image reading method according to the present invention, a drive pulse is applied to the photodiode at regular intervals,
In the image reading method of reading the amount of light incident on the photodiode as an electric signal within the certain time by integrating the current flowing out from the photodiode while the drive pulse is being applied, the photodiode and the output line To the pseudo-photodiode that is common to, applying a pseudo drive pulse that rises when the drive pulse rises and falls when the drive pulse rises,
An image reading method in which time integration is performed until after the drive pulse falls, or a drive pulse is sequentially applied to a plurality of photodiodes having a common output line at regular intervals, and the drive pulse is applied. In the image reading method of reading the amount of light incident on the photodiode as an electric signal within the certain time by integrating the current flowing out from the photodiode during the period, the photodiode to which the drive pulse has been applied is , After the driving pulse applied to the next photodiode falls, the auxiliary driving pulse that rises when the driving pulse applied to the next photodiode rises Applies to image reading method with time integration up to Rukoto is also possible.

The image reading apparatus according to the present invention further includes a photodiode, a drive circuit for applying a drive pulse to the photodiode at regular time intervals, and a flow out of the photodiode while the drive pulse is being applied. In an image reading apparatus including a signal processing circuit that integrates a current with time, a pseudo photodiode that shares an output line with the photodiode, and rises when the drive pulse rises and falls when the drive pulse rises in the pseudo photodiode. A pseudo drive circuit for applying a pseudo drive pulse is provided, and the signal processing circuit is configured to perform time integration until after the drive pulse has fallen, or a plurality of output lines in common. Driving pulse to the photodiode and the photodiode at regular intervals In an image reading apparatus including a drive circuit for sequentially applying the drive pulse and a signal processing circuit for time-integrating the current flowing out from the photodiode while the drive pulse is being applied, The diode is provided with an auxiliary drive circuit that applies an auxiliary drive pulse that rises when the drive pulse applied to the next photodiode falls and that falls when the drive pulse applied to the next photodiode rises, and It is also possible to apply the signal processing circuit to an image reading apparatus configured to perform time integration until after the drive pulse falls.

According to the image reading method or the apparatus thereof, the drive pulse is applied to the photodiode by the drive circuit at regular intervals, and the pseudo drive pulse is applied to the pseudo photodiode by the pseudo drive circuit. Since this pseudo drive pulse is designed to fall when the drive pulse rises and rise when it falls, the capacitance kick caused by the capacitance of the photodiode and the capacitance kick caused by the capacitance of the pseudo photodiode are Most of these are canceled out by becoming opposite to each other.

However, since there is a difference in these capacities, the capacitance kick is not completely canceled out, and only a small amount remains. That is, when the capacitance of the photodiode is larger, the residual component of the capacitance kick appears as positive noise when the drive pulse rises and appears as negative noise when the drive pulse falls. On the contrary, when the capacitance of the pseudo photodiode is larger,
The residual component of the capacitance kick appears as negative noise when the drive pulse rises, and appears as positive noise when the drive pulse falls. Since the residual components of these capacitance kicks are not only reversed in polarity but also remain due to the capacitance difference between a certain photodiode and the pseudo photodiode, their magnitudes are exactly the same. become. Therefore, not only while the drive pulse is being applied by the signal processing circuit, but also when the current flowing out from the photodiode is integrated over time after the drive pulse falls, these residual components of the capacitance kick are completely offset. Then, only the amount of light incident on the photodiode within the fixed time is read out as an electric signal.

Further, drive pulses are sequentially applied to a plurality of photodiodes by a drive circuit or the like at regular time intervals, and an auxiliary drive pulse is applied by the auxiliary drive circuit or the like to the photodiodes to which these drive pulses have been applied. It This auxiliary drive pulse rises when the drive pulse applied to the next photodiode falls and falls when the drive pulse applied to the next photodiode rises, so the drive pulse rises. The capacitance kick that sometimes occurs is canceled by the capacitance kick that occurs when the auxiliary drive pulse that is applied to the photodiode that precedes it falls, and the capacitance kick that occurs when the drive pulse falls is applied to the photodiode that precedes it. This is offset by the capacitance kick that occurs when the auxiliary drive pulse that rises is raised.

As described above, most of the capacitance kicks are canceled out, but the capacitances of these three photodiodes are different from each other, so that the capacitance kicks are not completely canceled out and a little remains. Not only the residual components of these capacitance kicks have opposite polarities,
They are almost the same in size because they remain due to the difference in capacitance between a particular photodiode and the one or two photodiodes before. Therefore, not only while the drive pulse is being applied by the signal processing circuit, but also when the current flowing out from the photodiode is integrated over time after the drive pulse falls, these residual components of the capacitance kick are almost completely canceled out. Then, only the amount of light incident on the photodiode within the fixed time is read out as an electric signal.

As described above, by adding the above configuration to the image reading method and apparatus according to the present invention, it is possible to easily reduce the noise associated with the driving voltage.

In addition, in the present invention, in addition to the charge storage type in which a capacitance kick is apt to occur, the photoelectric conversion element is CdS-C.
It can be applied to photoconductive type using dSe etc.
The present invention can be carried out in a mode in which various improvements, modifications and variations are added based on the knowledge of those skilled in the art without departing from the spirit of the invention.

[0061]

According to the image reading method and the apparatus therefor of the present invention, the driving side for applying the driving voltage to the photoelectric conversion element is divided into y blocks for each x, and the first block is divided by the matrix of x × y. Since the driving voltage and the second driving voltage are sequentially shifted to sequentially drive the photoelectric conversion elements or a fixed number of photoelectric conversion elements divided into blocks, the number of gates on the driving side is increased. Can be configured to be extremely small, and an inexpensive image reading device can be provided. Moreover, since the configuration of the analog section can be reduced, it is possible to configure a device resistant to noise.
Further, since the driving voltage has a high noise margin, the design of the image reading device becomes simple. Further, the reading speed of the image reading apparatus is greatly affected by the performance of the drive-side shift register, but by forming a matrix, the reading speed can be improved regardless of the performance of the shift register.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an image reading method and apparatus according to the present invention.

FIG. 2A is an explanatory diagram showing a basic configuration of the image reading method and apparatus shown in FIG. 1, and FIG. 2B is a diagram for explaining the basic operation thereof.

3 (a) is a circuit diagram of an image reading method and apparatus which simplifies the embodiment shown in FIG. 1, and FIG. 3 (b) is a time chart for explaining the operation thereof. .

FIG. 4 is a circuit diagram showing another embodiment of an image reading method and apparatus according to the present invention.

5A and 5B are diagrams for explaining a basic configuration and a basic operation of the image reading method and apparatus shown in FIG.

6 (a) is a circuit diagram of an image reading method and apparatus which simplifies the embodiment shown in FIG. 4, and FIG. 6 (b) is a time chart for explaining the operation thereof. .

FIG. 7 (a) is a circuit diagram showing another embodiment of the image reading method and apparatus according to the present invention, and FIG. 7 (b) is a time chart for explaining the operation thereof.

FIG. 8 is a circuit diagram showing an example of a conventional image reading apparatus.

9 is a time chart for explaining the operation of the conventional example shown in FIG.

[Explanation of symbols]

10; Photodiode (photoelectric conversion element) 12; Blocking diode 18, 20, 22, 24; Image reading device B _1, B _{2, ...} B _n ; First block C _1, C _{2, ...} C _y Second block D; first drive voltage E; second drive voltage Rd, Re, R; resistance Did, Die; diode D _1, D _{2, ...} D _y ; input terminals E _1, E _{2, ... Ex} ; input terminal

Claims (6)

[Claims] 1. An image reading method for sequentially applying a drive voltage to a plurality of one-dimensionally arranged photoelectric conversion elements to read an electric signal of the photoelectric conversion elements, wherein the driving voltage is applied to the photoelectric conversion elements. The side is divided into y blocks for each x, and the first drive voltage is sequentially applied in units of x photoelectric conversion elements in the block, and the blocks are relatively in the same position. A second driving voltage is sequentially applied in units of photoelectric conversion elements, and when the first driving voltage and the second driving voltage are simultaneously applied, the photoelectric conversion elements can be driven. Image reading method. 2. A plurality of one-dimensionally arranged photoelectric conversion elements are divided into n first blocks every m, and a driving voltage is set in units of m photoelectric conversion elements in the first block. In the image reading method for sequentially applying the driving voltage to the photoelectric conversion element to read the electric signal of the photoelectric conversion element, the driving side for sequentially applying the driving voltage to the divided n first blocks is further divided into y-th driving blocks for every x-th driving block. The first drive voltage is sequentially applied in units of x first blocks in the second block, and the first blocks are relatively located at the same position between the second blocks. When the second drive voltage is sequentially applied to each block and the first drive voltage and the second drive voltage are simultaneously applied to the first block, m photoelectric conversion elements in the first block are applied. An image reading method characterized in that it is driven in units of. 3. An image reading apparatus in which a driving voltage is sequentially applied to a plurality of one-dimensionally arranged photoelectric conversion elements to read out an electric signal of the photoelectric conversion elements, and the driving voltage is applied to the photoelectric conversion elements. The drive side is divided into y blocks for each x, and a first drive voltage is applied in order for each x photoelectric conversion element in the block.
And a second applying means for sequentially applying a second drive voltage in units of photoelectric conversion elements located at the same relative position between the blocks, the first drive voltage and the second drive An image reading apparatus, comprising: a matrix driving unit that applies a driving voltage for driving the photoelectric conversion element when the voltage and the voltage are simultaneously applied. 4. A plurality of one-dimensionally arranged photoelectric conversion elements are divided into n first blocks every m, and first photoelectric conversion elements are divided into n first blocks.
In an image reading apparatus in which a driving voltage is sequentially applied in units of m photoelectric conversion elements in a block and an electric signal of the photoelectric conversion element is read, the driving voltage is sequentially applied to the divided n first blocks. The driving side to be applied to the first block is further divided into y second blocks for each x, and the first driving voltage is sequentially applied in units of x first blocks in the first second block. And a second applying means for sequentially applying a second drive voltage in units of the first blocks that are relatively in the same position between the second blocks, the first drive voltage and the second drive voltage. And a drive voltage for driving m photoelectric conversion elements in the first block as a unit when the drive voltage is applied to the first block at the same time. . 5. The image reading apparatus according to claim 3, wherein the matrix driving unit is configured by an adder circuit including a resistor. 6. The method according to claim 3, wherein the matrix driving unit is configured by an AND circuit.
The image reading device described in 1.