JPS59119959A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To obtain the picture signal data corresponding to the optical information without using a compensating circuit by reading out the optical detection information at the same time point of a transient state or in a steady state to a photodetecting element having the transient response characteristics. CONSTITUTION:The voltage is applied to each input terminals 61-6n of blocks 51-5n from a voltage applying circuit 10 which consists of a voltage scanning circuit 3 of a shift register, etc. and N units of exclusive OR gates 111-11n corresponding to blocks 51-5n. The voltage signals P1-Pn are supplied to each input terminal of one side of gates 111-11n; while a rectangular wave signal T having 1/2 duty ratio is applied to the input terminal of the other side, respectively. When the 1st block 51 is read out, the voltage is applied to the block 51 for a period when photodetecting elements 111-11m are read out. Thus the optical information is read out from each element 111-11m of the block 51.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a one-dimensional solid-state imaging device, and particularly relates to an improvement of a solid-state imaging device using photoconductivity and P4.

[Technical background of the invention and its problems]

2. Description of the Related Art Conventionally, in facsimiles and the like, a one-dimensional solid-state imaging device whose sensor portion is made of a photoconductive film has been used as one of the imaging devices r for reading images. This device reads documents by making the sensor section the same as the reading width (size of the sent document), making the overall configuration more compact compared to image sensors using CCDs, and further improving the positional accuracy of the optical system. It has the advantage of being able to FIG. 1 is a schematic configuration diagram showing an example of such a solid-state imaging device. In the figure, 1 is a sensor section formed by arranging a plurality of photodetecting elements made of photoconductive films in one direction, and 2 is a sensor section 1. A load resistor 3 is connected to each element of the sensor section 1, a voltage scanning circuit 3 sequentially applies a voltage to each element of the sensor section 1, and an amplifier 4 that reads out the current flowing through each element of the sensor section 1.

By the way, in the device having the above-mentioned configuration, as the number of photodetecting elements increases, the number of wirings thereof increases significantly. For example, in the case of A4 size and pixel density of 8 [pixels/vm], the number of photodetecting elements is 1728, and the number of wires is 3456 including the voltage application side and the readout side. Such an increase in the number of wires is undesirable because it complicates the connection process and increases manufacturing costs.

Recently, a solid-state imaging device (Japanese Unexamined Patent Publication No. 55-67270) as shown in FIG. 2 has been developed to solve the above problem. This has a matrix configuration in which the photodetecting elements are divided into N blocks of M pieces each, and the number of wirings is (M+N), which is significantly smaller than the number of elements. For example, the same A4 size as above, pixel density 8 [
pixel/hu], if M=32 and N-54, the number of wires will be 86.

The configuration and operation of the apparatus shown in FIG. 2 will be explained below. The MXN photodetecting elements are divided into M blocks each consisting of N blocks 5.
It is divided into blocks from 1+ to 5n. The photodetecting elements of each block 5I, ~2, 5n, for example, the first block, the quintuple photodetecting elements JIg+711+~, 1 weight, have one end commonly connected to the block input end 61. Other blocks 51. ~． The same applies to An. Then, one pressure is sequentially applied to the block input terminals 6I, . . . , 6n by the box pressure scanning circuit 3 at fixed time intervals. That is, voltage signals P++ to Pn as shown in FIG. 3 are applied to blocks 1'+ii6++ to 6n, respectively. Block 5I, ~, 5n
For example, the first photodetecting element I II r1! +, . . . , 1n1 have their other ends connected to the signal output terminal 71. The same applies to the second and subsequent photodetecting elements. Signal output end 7 indigo,
~.

7m are grounded via load resistors 21r and 2m, respectively, and are also connected to the switch scanning circuit 8. The switch scanning circuit 8 has signal output terminals 71r~, 7
It is intended to sequentially select the detection information appearing at m at fixed time intervals, and the detection information selected by this circuit 8 is to be outputted via the amplifier 4.

When a voltage is now applied to the first block 5I, each of the 5+ photodetecting elements Jll t J1 * j ~,
11m is a load resistor 21 that carries a current according to each optical information.
Flow to 2m. And load resistance 2, ~1
Each voltage drop (detection information) of 2m is detected by the switch scanning circuit 8.
are sequentially selected and output from the amplifier 4 as image signal data. When the reading of the first block 5M is completed, the voltage scanning circuit 3 reads the second block 5M. Pressure is applied to block 5. in the same manner as above. The detection information is read. By repeating this, one line of both fi 77 data will be obtained.

However, there is a problem with the 11th order in the use of this scale. In other words, the sensor section consisting of the 7" Each Kanayama element generally has transient response characteristics as shown in Figures 4(a) and (b).In other words, Figure 4(d)
The photodetection output after the voltage is applied as shown in FIG. 3B tends to be large at F at the time of application and decrease as time passes. This is due to the contact between the electrodes of the main lit element. Therefore, when the optical information of a random number of photodetecting elements in a block is read out 7I'i times, the first readout is the photodetection output of the first photodetection element, for example, and the last readout is the photodetection output of the first photodetection element IBm. There is a difference in output even if the information is from the same source. Therefore, when applying voltages as shown in FIG. 3 to N blocks and reading optical information from M photodetecting elements for each block, one line of image signal data is as shown in FIG. The output waveform is wavy as shown above. therefore,
In the configuration shown in Fig. 2, some kind of correction circuit is required to obtain uniform data corresponding to optical information, and the addition of this correction circuit complicates the device configuration and further increases costs. Become. Note that the above-mentioned problem is not limited to photodetecting elements using photoconductive films, but also applies to photodiodes that exhibit transient characteristics due to junction capacitance.

[Purpose of the invention]

An object of the present invention is to be able to obtain image signal data corresponding to optical information without using or without a correction circuit for correcting the transient response characteristics of a photodetecting element, improving detection accuracy, and simplifying the device configuration. An object of the present invention is to provide a solid-state imaging device that can be made more compact and cost-reduced.

[Summary of the invention]

The gist of the present invention is to read light detection information from a light detection element having transient response characteristics at the same point in time in a transient state or in a steady state.

In other words, the present invention includes a sensor section including a plurality of photodetecting elements arranged in one direction, a sensor section that is divided into blocks for each predetermined number of elements, and a voltage for reading optical information in each block. an electric and pressure applying circuit for applying the voltage, and an output circuit for reading out the detection output corresponding to the optical information of each element by applying the voltage one by one for each block (ffii
In the solid-state imaging device comprising: The voltage application to each block is controlled.

〔Effect of the invention〕

According to the present invention, for a photodetecting element having transient characteristics,
Since the detection output is read out at the same point in time in the transient state or in the I″i steady state, the readout conditions for each photodetector element are the same.

Therefore, it is possible to prevent non-uniformity of both signal data due to a change in the detection output caused by the transient response characteristic of the photodetector to the applied voltage. For this reason,
A detection output corresponding to optical information can be obtained without using a complicated correction circuit. Therefore, it is possible to increase the accuracy of the moxibustion output with respect to optical information, and also to reduce the size and cost of the device configuration.

[Embodiments of the invention]

FIG. 6 is a schematic diagram showing an embodiment of the present invention. Note that the same parts as in FIG. 2 are denoted by the same reference numerals, and detailed explanation thereof will be omitted. In this embodiment, the detection output of a photodetecting element having transient response characteristics is read out at the same time point in a transient state, and the voltage application means is different from the device shown in FIG. 2. That is, the blocks 51 to a5n
A voltage, which will be described later, is applied by a voltage application circuit 10 to each input terminal 6, .about.+6n. The voltage application circuit lol includes a voltage scanning circuit 3 such as a shift register and a block 5.

~, N exclusive 411 OR gates corresponding to 5n (
Hereinafter abbreviated as EX-OR dart 1) 1no+.

~, 11n. The voltage scanning circuit 3 supplies voltage signals PI+ to Pn shown in FIG.
are supplied, respectively, and EX −OR11t + ~
A rectangular wave signal T outside the duty ratio is applied to the other input terminal of I'i at a constant period as shown in FIG.

With such a configuration, the voltage output from each output terminal of the voltage application circuit 10, that is, the block input terminal 61
Voltage Q1, ~v Q applied to +~, 6n, respectively
n is as shown in FIG.

Therefore, for example, when reading out the first block 5I, a voltage is applied to the first block 5I during the period (shaded area Q1 in FIG. 7) during which each element 1, lIl, . ．． .

No voltage is applied to ~1,5n. Therefore, each element Jll+JI of the first block 5! Optical information from t to 11m is read out. At this time, each element 1 ++ +1 +
A rectangular wave with a constant period is applied to tr~, 1x m, and each element 711+111r~a Jam will be read out in that transient state, but each element 1st+II*
*~, the voltage application conditions before reading IHm are substantially the same. In other words, the photodetector element 'IIs''I!r~
, 11m, information is read out at the same time point in the transient state.

After the first block 5I has been read, the second block 5! Reading is also performed in the same manner as in the first block 5I. That is, voltage is applied only to the second block 5, and to the other blocks 5 and 5.

No voltage is applied to 5B, . . . , 5n, and the photodetector elements 12
The detection outputs of 1rl**e~ and 12m are read out at the same time in the transient state. The same applies to the third to Nth blocks.

In this case, as described above, each block 51, .
For 5n, the photodetecting element only performs information reading at the same point in time in its 3I') wave state and in the recirculation-readout condition. Therefore, there is no problem such as a change in the detection output due to the transient response characteristics of the photodetector, and image signal data for one line can be uniform and correspond to the optical information.

FIG. 8 is a schematic configuration diagram showing another embodiment.

Note that the same parts as in FIG. 6 are given the same reference numerals, and detailed explanation thereof will be omitted. In this embodiment, a detection output is read out in a steady state from a photodetector having a pan-Water response characteristic, and the only difference from the previously described embodiment is the configuration of the voltage application circuit 10. Everything else is exactly the same.

That is, the voltage application circuit 10 is connected to the voltage scanning circuit 3 and N
It is composed of OR gates 12I, . . . , 12n. Then, one input terminal of the ORG) 12in~, 12n is connected to a voltage signal P++~, as shown in FIG.
tn is applied to each, and a voltage signal R as shown in FIG. 9 is applied to the other.

With such a configuration, the voltage output from each output terminal of the voltage application circuit 10 is equal to or smaller than the voltage output from each output terminal.

The voltages SI+~, applied to the input terminals 6I,~, 6n
Sn is as shown in FIG. That is, voltage application to one block and voltage application to all blocks are alternately repeated. Therefore, for example, when reading the first block 51, each element number 11+112+~v'11
During the period of reading m (details after SI in FIG. 9), a voltage is applied to the first block 53, and the other blocks 53. ~．
No voltage is applied to sn. Therefore, the optical information detection output of each element 1st, 1st, .about.+hm of the first block 51 is read out. At this time, each element 711+Jl*+~l
+m is read out after a certain period of time has elapsed since the voltage was applied.

Therefore, if the above-mentioned time is made longer than the time in the completion state, the photodetecting element 11m1Ixp can be
Each detection output of ~elIrn will be read out.

After the first block 5I has been read out, the second block 52 is read out in the same manner as the first block 51. After a certain period of time has elapsed since the voltage was applied to all blocks 5I, 5n, including the second block 5, the second block 5 and the blocks 5I +5r~
, 5n is blocked, and the second block 5. The detection outputs of the photodetecting elements 1ws+1**+ to 18m are read out in a steady state. The same applies to the third to Nth blocks 58, -, 5n.

Therefore, information is read out from the photodetecting elements for each block quintuple, . Therefore, the same effect as in the previous embodiment is achieved.

It should be noted that the present invention is not limited to the embodiments described above, and can be implemented with various modifications without departing from the spirit thereof. For example, the photodetecting element is not necessarily one that uses a photoconductive film, but may be one that has a junction capacitance, such as a photodiode or a lance nut. It can be applied to devices having transient response characteristics as shown in FIG. However, in the embodiment, the output of the EX-CR gate or OR gate is directly supplied to each block, but the output of the dart mentioned above is used to turn on and off MOS transistors, etc. to supply voltage to each block. It may be applied as a case.

Furthermore, it goes without saying that the number of elements and the number of blocks may be determined as appropriate depending on the specifications.

[Brief explanation of the drawing]

FIGS. 1 and 2 are schematic configuration diagrams showing conventional solid-state imaging devices, FIGS. 3 to 5 are signal waveform diagrams for explaining the problems of the conventional devices, respectively, and FIG. A schematic configuration diagram showing one embodiment of the invention, FIG. 7 is a signal waveform diagram showing the output voltage waveform of the voltage application circuit used in the above embodiment,
FIG. 8 is a schematic configuration diagram showing another embodiment, and FIG. 9 is a signal waveform diagram showing the output voltage waveform of the voltage application circuit used in the other embodiment. l...Sensor section, 1st eye, ~, l nm...Unexpected light detection, 21+~r2m...Load resistance, 3...Voltage scanning circuit, 4...Amplifier, 5I, ~r5n・...Block, 61, ~, 6n...Block Jinrikirei;, 71
r~. 7m...Signal output end, 8...Nuitch scanning circuit, 1
0...° box 7 pressure application circuit, 11. , ~, 11n...E
X −OR'r ), 12+ r ~+
12 n...OR dirt.

Claims (4)

[Claims] (1) A sensor section consisting of a plurality of photodetecting elements arranged in a row in one direction; and a sensor section that is divided into blocks for each predetermined number of elements, and a voltage applied to each block to read optical information. and an output circuit that sequentially reads out detection outputs corresponding to optical information of each of the elements by applying the voltage to each of the blocks, the voltage application circuit comprising:
A voltage is applied to each block so that the reading of the detection output by the output circuit is carried out at the same point in time in a transient state or in a steady state for each photodetecting element having a transient characteristic in response to the application of voltage. A solid-state imaging device characterized by the following. (2) The solid-state imaging device according to claim 1, wherein the photodetecting element is made of a photoconductive film. (3) The solid-state imaging device according to claim 1, wherein the front power distribution and pressure application circuit alternately applies voltage to the block to be read and voltage to other blocks. . (4) The voltage application circuit applies a rectangular wave of a constant period to the block to be read, and applies a rectangular wave of opposite polarity to the above to other blocks. The solid-state imaging device according to item 1.