JPS61157185A - Image pickup device - Google Patents

Abstract

PURPOSE:To make a signal processing system easy by reading simultaneously plural row signals, calculating plural row signals mutually and forming an outline correcting signal. CONSTITUTION:At an odd field, an n1 line information is formed from l1 and l2, an n2 line information formed from l3 and l4, an n3 line information is formed from l5 and l6 and at an even field, an m1 line information is formed from l2 and l3, an m2 line information is formed from l4 and l5, and a m3 line information is formed from l6 and l7. Therefore, two horizontal line infor mation is simultaneously read and the information is outputted to the output terminal of 47 and 58 respectively. At the odd field, by reducing the output of a terminal 47 from the output of a terminal 58, an outline signal is formed, the level of the outline signal is adjusted by a resistance 71, and thereafter, the level is added by an original signal and an adder 71 and the video signal, whose outline is corrected, is obtained. At the even field, by reducing the output of the terminal 58 from the output of the terminal 47, the outline signal is formed, the level of the outline signal is adjusted by a resistance 7, and there after, the level is added to the original signal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an imaging device using a photoelectric conversion element having a photoelectric conversion element whose potential is controlled via a capacitor.

The imaging device according to the present invention includes, for example, an image input device, a workstation, a digital copying machine, a word processor,
It can also be applied to barcode leagues, photoelectric conversion object detection devices for autofocus of cameras, video cameras, 8mm cameras, etc.

(Prior Art) In recent years, research on photoelectric conversion devices, particularly solid-state imaging devices, has been conducted mainly on two types: CCD type and MOS type.

A CCD type imaging device forms a potential well under an MO3 type capacitor electrode, stores charges generated by incident light in this well, and during readout, these potential wells are sequentially moved by a pulse applied to the electrode to accumulate the charges. It uses the principle that the generated charge is transferred to the output amplifier and read out. Therefore, the structure is relatively simple, the noise generated by the CCD itself is small, and low-light photography is possible.

On the other hand, the MO5 type imaging device has a pnta that constitutes the light receiving section.
The charge generated by the incidence of light is accumulated in each of the photodiodes consisting of a photodiode, and during readout, the accumulated charge is read out to the output amplifier by sequentially turning on the MOS switching transistors connected to each photodiode. It uses principles. Therefore, C.C.
Although it is structurally more complex than the D type, it can have a large storage capacity and widen the dynamic range.

However, these conventional imaging devices have the following drawbacks, which have been a major hindrance in the pursuit of higher resolution in the future.

In a CCD type imaging device, 1) since a MOS type amplifier is installed on-chip as an output amplifier, noticeable l/f noise is generated on an image from the interface between silicon and silicon oxide film. 2) If the number of cells is increased to achieve higher density in order to achieve higher resolution, the maximum amount of charge that can be stored in one potential well decreases, making it impossible to obtain a dynamic range. 3) Since the structure is such that accumulated charges are transferred, if there is even one defect in a cell, charge transfer will stop there, resulting in poor manufacturing yield.

In a MOS type imaging device, 1) a large signal voltage drop occurs because a wiring capacitor is connected to each photodiode during signal readout; 2) The wiring capacitance is large, which causes a large amount of random noise. 3) Scanning MO
Fixed pattern noise is mixed in due to variations in the parasitic capacitance of the S switching transistors. This makes low-light imaging difficult, and when each cell is reduced in size to achieve higher resolution, the accumulated charge is reduced, but the wiring capacitance is not reduced so much that the S/N ratio is reduced.

As described above, CCD type and MOS type image pickup devices have a problem with increasing resolution. A new type of semiconductor imaging device has been proposed for these imaging devices (Japanese Patent Laid-Open No. 150878/1983, Japanese Patent Laid-Open No. 56-150878).
157073, JP-A-56-165473). The method proposed here transfers charges generated by incident light to a control electrode (e.g., the base of a bipolar transistor, a static induction transistor SIT, or a MOS).
h transistor (gate), and the accumulated charge is amplified using the amplification function of each cell and read out. This method allows high output, wide dynamic range, low noise, and nondestructive readout, and has the potential for high resolution.

However, this method is basically an X-Y address method, and each cell has a basic structure that combines a conventional MO5 type cell with amplifying elements such as bipolar transistors and SIT transistors, so it is difficult to achieve high resolution. There are limits to.

In addition, in conventional non-destructive readout imaging devices, the width of the X-Y address wiring was set to the minimum width in order to ensure the aperture ratio of the device, and as a result, the wiring capacitance was small, limiting the gain of the imaging device. There was a drawback to it.

In addition, as shown in FIG. 14(a), in the conventional contour compensation circuit, the IH delay line 60.61 and the adder 63.65
．． 66, a coefficient circuit 64, and a level adjustment resistor 67 to form a signal with an enhanced outline as shown in FIG. 14(b).

However, this method requires the use of two expensive delay lines and has the disadvantage that the circuit configuration becomes complicated.

In FIG. 14(b), for example, a to d are the signal waveforms of each part of the odd field, d' is the output of the adder 65 in the even field, d'' is the contour signal in the frame image, and e'' is the frame image The signal after contour enhancement is shown.

(Objective) An object of the present invention is to provide an imaging device that solves the above-mentioned problems.

Another object of the present invention is to provide an imaging device that can form high-quality images with a simple configuration.

(Example) Next, an example of the photoelectric conversion device of the present invention, which is configured by two-dimensionally arranging the optical sensor cells according to the configuration described above, will be described with reference to the drawings.

FIG. 5 shows a circuit configuration diagram of a photoelectric conversion device in which basic optical sensor cell structures are two-dimensionally arranged.

The basic optical sensor cell 30 surrounded by the dotted line already explained
(At this time, the collector of the bipolar transistor is shown to be connected to the substrate and the substrate electrode.), horizontal line 31°31', 31'' for applying readout pulse and refresh pulse; 1 readout pulse; Vertical shift register 32 for generating vertical shift register 32 and horizontal lines 31, 31', 3
1”-111, buffer MOS transistor 3
3, 33', 33''----, buffer MOS
Transistors 33, 33', 33'' --- Terminal 34 for applying a pulse to the gate of one, buffer MO5) for applying a refresh pulse, transistor, ---
-35, 35', 35'', terminal 36 for applying pulses to its gate, vertical shift register 52 for applying refresh pulses, elementary photosensor cell 3
Vertical line 38.38' for reading the stored voltage from 0
, 38'''-1--1 and 51, 51', 51''
---1 Horizontal shift register 39 for generating pulses for selecting each vertical line, MO3) transistors 40, 40' for gates for opening and closing each vertical line.

40 ``----149, 49', 49'' Output line 41.59 for reading out the accumulated voltage to the amplifier section, MOS transistor 42゜53, MOS for refreshing the charge accumulated in the output line after reading out ) Langimeta 42.53 terminals 43, 54 for applying heli refresh pulses, bipolar for amplifying the output signal, M
O.S.

Transistor 44.55 such as FET, J-FET, load resistance 45.56 and terminal 46.57 for connecting the transistor 44.55 to the power supply, transistor output terminal 4
7.58, vertical lines 40, 40 in read operation
', 40''---149, 49', 49''---
--MOS for refreshing the charge accumulated in
) transistor, ----48, 48', 48'',
-----50, 50'.

50″ and MOS transistor, ----48.

48', 48'',---50, 50', 50
This photoelectric conversion device is constituted by a terminal 49 for applying a pulse to the gate of ``.

Further, in the imaging device of the present invention, each part 32 of the photoelectric conversion device,
It has a clock driver CKD for supplying drive pulses to 34, 36, 39, 43, 49.degree. 54, and a clock generator CKG for supplying timing pulses to this clock driver. In addition, these clock driver CKD and clock generator C
KG constitutes a control means.

Next, FIG. 6 is a diagram showing a method of driving the imaging device by the control means, and sentences 1 to 6 are row information consisting of each sensor cell,
In the odd field, as shown in the figure, the n1 line from intersection 1 and sentence 2, the n2 line from fL3 and sentence 4, and the n3 line from fL3 and sentence 6.
Form the line information, and in the even field, the ml line from Sentence 2 and Look 3, and Dan 4! ;L5 to m2 line, I;L
m3 line information is formed from e and sentence 7.

For this purpose, two horizontal line information are read out at the same time, each with 47.
This information is output to the 58 output terminal.

Next, FIG. 7 is a diagram showing an example of the configuration of an imaging device according to the present invention, and 100 in the figure is the 5th r! Photoelectric conversion device as shown in lJ, 68
69 is a subtracter, 70 is a level adjustment resistor, and 71 is an adder. be. Note that this embodiment can also be applied to a conventional X-Y address type MOS image sensor.

That is, in an odd field, a contour signal is formed by subtracting the output of terminal 47 from the output of terminal 58, and after adjusting the level of this contour signal with resistor 71, it is combined with the original signal and adder 71.
to obtain a contour-corrected video signal. In the even field, a contour signal is formed by subtracting the output of terminal 58 from the output of terminal 47, and after adjusting the level of this contour signal with resistor 7, it is added to the original signal.

Note that the clock driver CKD switches the switch 68 for each field. As described above, the first embodiment of the present invention has the effect that contour correction can be performed without using a delay circuit, and the circuit configuration is extremely simple. Note that APC is a contour signal forming block as a contour signal forming means.

Next, FIG. 8(a) is a diagram showing a second embodiment of the present invention, which uses a photoelectric conversion device that reads out information on three horizontal lines at the same time.

In this embodiment, the output of the photoelectric conversion device 100 is obtained by simultaneously reading three adjacent horizontal lines.

Also, the same numbers as in Fig. 5 indicate the same elements, and 1
01 is a switch circuit controlled by a clock driver CKD.

The waveforms of each part obtained in this way are as shown in FIG. 8(b), where a to d are the waveforms of each part of the odd field, d' is the output waveform of the adder 65 of the even field,
d'' indicates the contour signal in the claim image.

FIG. 9 is a diagram for explaining the connection of the output line of the photoelectric conversion device 100 and the reading method using the clock driver.

In this embodiment, in the odd field, the clock driver simultaneously reads out the lines 1 to 3 as the n1 line, the lines 3 to 5 as the n2 line, and the lines 5 to 7 as the n3 line. reading.

Lines 7 to 9 are read out simultaneously as the n4 line.

Also, in an even field, the m1 line is 9.2 to 4.
Lines 4 to 6 are read out simultaneously as m2 lines, and lines 4 to 6 are read out as m3 lines! ;L
6~! Read out lines L8 at the same time.

By reading in this way, the following effects can be obtained. First, when vertical correlation processing is performed, false signals are less likely to appear at edge portions and sensitivity is improved. In addition, it is easy to perform contour correction as described later.

Figure 10 shows the outputs Φ1゜02 and Φ3 of the photoelectric conversion device 100.
This is a diagram illustrating the configuration of a switch circuit 101 for associating outputs a, b, and c in FIG.

Further, as shown in FIG. 11, the output from the clock driver CKD is switched at different timings for each field and each row.

In this way, since the switch circuit 101 is provided in this embodiment, it is only necessary to configure the contour compensation circuit for one combination of a, b, and c as shown in FIG. 8(a), and the configuration is extremely simple. It's easy.

Next, FIG. 12 is a diagram showing a third embodiment of the present invention.
6.78.83 is an adder, 75°79 is a weighting circuit,
77 is a level adjustment resistor, 80 is a switch circuit, 81 is a brightness processing circuit, and 82 is a color processing circuit.

According to this embodiment, similar to the second embodiment, contour correction can be performed without using any delay line or the like, and the configuration of the switch circuit 80 is simplified. Also, of course, there is an effect that only one system is required for the circuit configuration of the subsequent stages 75 to 79, and the wiring within the photoelectric conversion device 100 is simplified.

FIG. 813 is a diagram explaining the switching control method of the switch 80. When reading three horizontal lines at the same time as shown in the same figure, the signal of the middle horizontal line is used as the original signal, and the signals of the upper and lower lines are used as the original signal. It is used as an IH delayed signal or an IH advanced signal.

As explained above, according to the embodiment of the present invention, the signals of a plurality of rows of a photoelectric conversion device for capturing an optical image are simultaneously read out, and the signals of the plurality of rows are mutually operated to form a contour correction signal. This makes the signal processing system extremely simple.

Furthermore, since a switch circuit is provided to change the combination of line signals before reading out signals from a plurality of lines and inputting them to the arithmetic circuit, only one system of arithmetic circuits is required, and the configuration of the arithmetic circuit is simplified.

Further, wiring within the photoelectric conversion device becomes easy.

In addition, when using a photoelectric conversion device that allows non-destructive readout, it is possible to read out the signals of three or more horizontal lines at the same time and shift them with some overlap each time a horizontal scan is performed. Correlation can be increased. Also, the contour signal is also 2
It is possible to create contour signals of the following or more. Note that the switch circuit may be provided within the photoelectric conversion device.

(Effects) As described above, according to the present invention, it is possible to obtain a contour correction signal with a simple configuration, and since it is generated from signals of adjacent pixel lines with a large vertical correlation, there are fewer false signals.

[Brief explanation of drawings]

FIG. 1(a) is a plan view of an optical sensor cell according to an embodiment of the present invention, FIG. 1(b) is a sectional view, FIG. 2 is an equivalent circuit, and FIG. 3(a) is an accumulation time and readout voltage. Figure 3 (b) is a diagram showing the relationship between bias voltage and read time, Figure 4 (&) is an equivalent circuit diagram during refresh operation, and Figure 4 (b) is a diagram showing the relationship between bias voltage and read time. A diagram showing the relationship with the base potential, FIG. 5 is a side view of the configuration of the imaging photoelectric conversion device,
FIG. 6 is a diagram for explaining the driving method, FIG. 7 is a diagram showing an example of an imaging device, FIG. 8 (&) is a configuration diagram of the second embodiment of the present invention, and FIG. 8 (b) is the waveform diagram, and Figure 9 is the second waveform diagram.
A diagram explaining the driving method of the embodiment, FIG. 10 is a diagram showing the configuration of the switch circuit 101, and FIG. 11 is a diagram showing the configuration of the switch circuit 10.
12 is a diagram illustrating a third embodiment of the present invention, FIG. 13 is a diagram illustrating a driving method of the switch circuit 80, and FIG. 14(a) is a configuration of a conventional contour compensation circuit. 14(b) are waveform diagrams of each part. 100... Photoelectric conversion device, CKD... Clock driver, CKG ・
・・Clock generator, 68.101.80
... Switch circuit. No./U;] and Otontsuta・? 2 Neat?ノ (゛I7 Beak 7th E Procedural Amendment Form G) 1. Display of the case 1982 Patent Application No. 276978 2, Name of the invention Imaging device 3, Person making the amendment Relationship to the case Patent applicant address 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (100)
) Canon Co., Ltd. Representative: Atsushi Kaku 3, Part 4, Agent address: 3-30-25 Shimomaruko, Ota-ku, Tokyo 146, Date of amendment order: April 30, 1985 (shipment date) 6. Subject of amendment: Particulars 7, Contents of amendment As per the engraving and attached sheet of the specification originally attached to the application (no change in content)

Claims (1)

[Scope of Claims] A photoelectric conversion device comprising a plurality of photoelectric conversion elements arranged in row and column directions, a control means for simultaneously reading out signals of a plurality of rows of the photoelectric conversion device, and a control means for calculating signals of the plurality of rows. An imaging device comprising a contour signal forming means for forming a contour correction signal.