JPH0346470A - Photoelectric converter - Google Patents

Abstract

PURPOSE:To attain correction of defect even when a sensor has high picture elements by reading a signal from a store means storing signals read from other elements when a signal from a desired photoelectric conversion element is a defect signal. CONSTITUTION:Electrodes 4 of each photoelectric conversion cell in horizontal lines HL<1>-HL<m> and gate electrodes of transistors(TRs) Q<x1>-Q<xm> connect to a terminal 3 via TRs Qv1-Qvm and a drive pulse phiR is inputted to the terminal 3. Gate electrodes of the TRs Qv1-Qvm connecting to the horizontal lines HL1-HLm are connected respectively to an output terminal of a vertical scanning circuit 1, to which the vertical scanning pulses phiV1-phiVm are applied respectively. A vertical scanning section 2 is formed by the circuit 1 and the TRs Qv1-Qvm connecting to each line. Emitter electrodes 5 of each cell are connected to the vertical lines VL1-VLn for each column and connect to ground via TRs Qr1-Qrn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photoelectric conversion device, and in particular to a photoelectric conversion element that accumulates photoelectrically converted signal charges and converts the signal charges without destroying the signal charges. The present invention relates to a photoelectric conversion device that can read out signals corresponding to.

INDUSTRIAL APPLICATION This invention is suitably used for defect correction of the image sensor used as an image input device.

[Prior Art] Conventionally, there have been the following photoelectric conversion devices capable of correcting defects existing in a plurality of photoelectric conversion elements.

FIG. 3 is a block diagram showing the configuration of a conventional photoelectric conversion device.

In FIG. 3, 21 is an image sensor, 22 is a clock IC 123 for driving the image sensor 21, is a defect correction circuit, 24 is a memory in which the position of the defect in the image sensor 21 is written, and 25 is an AND circuit. , 26 is an S/H (sample and hold) circuit that holds the sensor output signal from the image sensor 21, and 27 is a signal processing circuit to which the S/HIC output is input.

S/H pulse of clock rc22 and defect correction circuit 23
The AND output with the defect correction pulse is input to the S/HIC 26, and when this AND output becomes high level, the signal of the defective pixel is replaced with the signal of the adjacent pixel. S/HI
The output of C26 is input to a signal processing circuit 27 to produce a video signal.

[Problems to be Solved by the Invention] However, in the conventional photoelectric conversion device described above, it is difficult to adjust the phase relationship between the sensor output signal and the S/H pulse. In particular, in the case of video signals, the signal is read out over several Ions, so it is very difficult to align the phase between the sensor output signal and the S/H pulse.If the phase adjustment is not done properly, defects become noticeable and cannot be corrected. There were drawbacks. Furthermore, as the number of pixels in the sensor increases, the signal readout time becomes shorter, which tends to make defect correction more difficult.

The present invention has been made in view of the above problems, and is based on S/HI
It is an object of the present invention to provide a photoelectric conversion device that does not require C and does not require phase adjustment between a sensor output signal and an S/H pulse.

[Means for Solving the Problems] The photoelectric conversion device of the present invention is capable of accumulating photoelectrically converted signal charges in a photoelectric conversion element and reading a signal corresponding to the signal charges without destroying the signal charges. A possible photoelectric conversion device has a first accumulation means for reading and accumulating a signal corresponding to the signal charge, and a second accumulation means for reading out and accumulating a signal corresponding to the signal charge again, and has the following: When the signal output from the photoelectric conversion element is a defective signal, the signal is read out from the second storage means for accumulating the signal read out from the photoelectric conversion element other than the desired photoelectric conversion element. Features.

[Function] When reading a signal corresponding to signal charges accumulated in a photoelectric conversion element, the present invention accumulates the signal in the first accumulation means in the first readout, and then reads it out again to perform the second accumulation. the second storage means for accumulating signals in the means, and for accumulating signals read from photoelectric conversion elements other than the desired photoelectric conversion element when the signal output from the desired photoelectric conversion element is a defect signal; The signal is read out from the sensor and used in place of the defect signal, and does not require a special circuit such as an S/HIC for defect correction, and eliminates the need for phase adjustment between the sensor signal and the S/H pulse. It is something.

[Example] Hereinafter, an example of the present invention will be described in detail using the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the photoelectric conversion device of the present invention, and FIG. 2 is a timing chart for explaining its operation.

In FIG. 1, the sensor is a two-dimensional image sensor composed of photoelectric conversion cells, which are photoelectric conversion elements arranged in m rows and n columns, and S, to S□ correspond to the photoelectric conversion cells.

The electrode 4 of each photoelectric conversion cell and the gate electrode of the transistor Qx+'wQx+* in each horizontal line HLI'-HLffi are connected to the terminal 3 via the transistors Qv+ to QV+a, and the drive pulse φ8 is input to the terminal 3. be done. The gate electrodes of the transistors Qv+ to Q□ connected to the horizontal lines HLI to HLm are respectively connected to the output terminals of the vertical scanning circuit (■), and vertical scanning pulses φ□ to φV are applied thereto, respectively. The transistor Q vl- connected to this vertical scanning circuit 1 and each line
A vertical scanning section 2 is formed by QV+a. The emitter electrode 5 of each cell is connected to a vertical line V t, t for each column.
~vL, 1, respectively, and transistors Q□~Q
Grounded via rTh. This transistor Q
r l~Q rn, photoelectric conversion cells S, ~S,. A photosensor section 6 is formed by the transistors Q, □ to Qxm connected to each line.

Vertical lines V Ll to vLn include photoelectric conversion cells S, ~S
l. A signal corresponding to the signal charge accumulated in is output.

Each vertical line V, ~VLn is connected to a transistor Qt+, ~
Q t l n and Q ta+ ~Qtzn-+
(Note that the transistors Q+zn are not provided here) are connected to the storage capacitors Ctll to Ct1. , and Ctz+~Ctan-1 (note that the storage capacitor Ct2.. is not provided here), and the storage capacitors Ctz~Ctln and Ctll~Ct2°-1 are connected to the transistors Q, ,t
++~Q dtll'l+ Qh+~Q hn and Q
dt2+~Q dt2n-1+Q ni~Qhn-+
It is connected to the output line L1 via. A horizontal scanning circuit 7 is connected to the gate electrodes of the transistors Q0 to Qhn.
Horizontal scanning pulses φ□ to φHn are applied from . The output line L1 is connected to the input terminal of the source follower circuit 9 and is grounded via the transistor Qrlc.

A horizontal clear pulse φHc is applied to the gate electrode of the transistor Qhe, and a sensor signal Sout is output from the output of the source follower circuit 9.

Next, the operation of this embodiment will be explained with reference to the timing chart of FIG. Note that FIG. 2 only shows the operation of the first horizontal line H1. Also, I in the figure
H indicates the horizontal scanning period of the television signal, and the period T
5 corresponds to its effective scanning period.

First, from the vertical scanning circuit 1, a vertical scanning pulse φ9. is output during the period IH, and the transistor Qv+ of the first horizontal line HLl is turned on.

Subsequently, in period T1, the pulse φa and the pulse φvc cause the transistors Q t + + to Q t
I n and Q, ~Q rn are turned on, and capacitors Ct + + ~Ctll are cleared.

Next, in period T2, transistor Q t +
+～Q t r n remains on and pulse φ8 is applied.
When the voltage is applied, each photoelectric conversion cell S, ~S In is forward biased, and the optical signal of each photoelectric conversion cell is transferred to the capacitor Ct.
It is stored at r r~C0°.

Subsequently, in period T, pulses φT2 and φv
c causes transistor Q, 2. ~Q tin-1 and Q rl ~ Q rn are turned on, and capacitor Ctz
Clear +~Ctin-1.

Furthermore, in period T4, transistors Q tx+ to Q
If a pulse φ8 is applied while keeping tin-+ in the on state, in the case of a sensor that can be read out non-destructively, the optical signal of each photoelectric conversion cell is again transferred to the capacitors Ct21 to Ct.
It is stored in E2n-1.

Subsequently, in the period Ts, the pulse φ8 is set to Low level, and the transistors Q and Q of each photoelectric conversion cell are
, is turned on, and the base potential of each photoelectric conversion cell is cleared to the ground level.

Furthermore, in period T6, pulse φ7 is set to High level to clear each photoelectric conversion cell again.

Period T y , To , Ti1l T181...
In the horizontal scanning circuit 7, the horizontal scanning pulse φ1.
φH2゜...φHn is output, and the transistor Q h
l+ Q1121...Q nn are respectively turned on. Also, period Ta.

T. , TI□, Ti4l..., the horizontal clear pulse φ□. is applied to turn on the transistor Qhc and ground the output line L1. Here, a defect correction pulse φ is applied to the terminal 8. is input, and the defect correction pulse φ. is input to the gate of the transistor Q at+, and is also input to the gate of the transistor Q at+ through the inverting circuit 10.
It is input to gate 2. In addition, the photoelectric conversion cell 5t-(
a is any number from 1 to n)
．． and the drain of Q aza is the transistor Q
r+ a and Q. (Connected to the sources of 1 and ■ respectively. Normally, the pulse φ is at High level,
The transistors Q at + r to Q at+n are on, but when reading out a defective pixel, they are set to Low level and the transistors Q atz+ to Q dt2n-1 are turned on.
is turned on. In FIG. 2, 5out' is a waveform containing a defective signal, and has a period T.

is the part of the defect signal. However, in period T I3, the pulse φ. When it changes from High level to Low level, transistor Qdtzb (transistor corresponding to the adjacent photoelectric conversion cell) turns on, reads out the signal (period T11) of the adjacent pixel (photoelectric conversion cell), and reads the signal (period T11) from the previous pixel. Correction can be made using the read signal.

In this example, photoelectric conversion cells S, (a is 1 to n
The drain of the transistor Q6°, corresponding to an arbitrary number of Although correction is performed using a signal, the same effect as in this embodiment can be obtained.

Furthermore, although a two-dimensional image sensor has been described in this embodiment, it can also be applied to a one-dimensional image sensor (line sensor), and the same effects as in this embodiment can be obtained.

[Effects of the Invention] As explained above, according to the photoelectric conversion device of the present invention, difficult phase adjustment between the sensor output signal and the S/H pulse becomes unnecessary, and at the same time defect correction is possible even when the sensor has a high number of pixels. The effect is that it can be done easily.

Additionally, special circuits for defect correction, e.g. S/HI
Since C and the like are not required, there is an advantage that the number of parts and cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the photoelectric conversion device of the present invention, and FIG. 2 is a timing chart for explaining the operation of the photoelectric conversion device. FIG. 3 is a block diagram showing the configuration of a conventional photoelectric conversion device. vertical scanning circuit, 2: vertical scanning section, 3: drive pulse input terminal, 4: gate electrode of transistor Q8, 5: emitter electrode of transistor T, 6: optical sensor section, 7: horizontal scanning circuit, 8: defect Correction pulse input terminal, 9: source follower circuit, 10: inverting circuit.

Claims (1)

[Claims] (1) In a photoelectric conversion device capable of accumulating photoelectrically converted signal charges in a photoelectric conversion element and reading a signal corresponding to the signal charges without destroying the signal charges, a signal corresponding to the signal charges is provided. The first step is to read and accumulate
and a second storage means for rereading and accumulating the signal corresponding to the signal charge, and when the signal output from the desired photoelectric conversion element is a defective signal, the desired photoelectric conversion element is A photoelectric conversion device characterized in that a signal is read out from the second accumulation means that accumulates a signal read out from a photoelectric conversion element other than the conversion element.