JPS59163981A - Image pickup device - Google Patents

Abstract

PURPOSE:To improve the yield by controlling a clamp means so as not to clamp a defective part in an image pickup device using an image pickup device. CONSTITUTION:After the duty is improved from an output of a device 100 by a sample-and-hold circuit 12, the result is inputted to a clamp pulse control circuit 13 to detect whether or not any defective signal exists in an optical black period. A clamp pulse applied to a clamp circuit 20 of the next stage is controlled in response to this detected output. DC regeneration is applied to a pedestal level into a reference black level at the clamp circuit 20 and various corrections are given at a process circuit 25 and the result is inputted to an encoder 30.

Description

TECHNICAL FIELD The present invention relates to an imaging device and an imaging device having a highly improved direct current regeneration circuit.

(Prior Art) Conventionally, in an imaging apparatus using an imaging device such as a COD, a clamp circuit for DC regeneration shields a part 4 of the imaging section 1 of the imaging element from light as shown in FIG. The signal 5 from this part was clamped by a clamp pulse 6 with the timing shown in Figure 2, and the lost DC component was regenerated. . In FIG. 1, 2 is a part of the memory, and 6 is a horizontal shift register. Figure 6 is a diagram showing a conventional clamp circuit.The signal from the signal source 8 becomes an AC signal with an average value of O■ due to the capacitor 7 as shown in Figure 4a. When the switch 9 is turned on at the timing shown in Fig. 4, the voltage at that point is pulled up to the voltage EV of the power supply E, and as a result, an image signal with the reference black level iEV as shown in Fig. 4 is obtained. However, in a clamp circuit with such a configuration, the fifth
If a defect such as a scratch exists during the ogical black period of the output of the imaging device as shown in FIG. a, the defect generally appears in the output as voltage fluctuation. If this is clamped with a pulse like 6, the voltage of the scratch will also be pulled by EV as shown in Figure 6, and as a result, the reference black level will deviate from EV by △■', and the reproduced image will be will be affected. As a result, there is a problem in that the yield of imaging devices is reduced.

(Purpose) The purpose of the present invention is to eliminate such conventional drawbacks. In particular, when there are scratches on the part of the imaging device that should be clamped, such as optical black,
The purpose of this is to perform correct DC regeneration and improve yield by controlling the clamping means so as not to clamp the portion where the flaw exists.

(Example) The present invention will be explained below based on Examples.

FIG. 7 is a block diagram of a first embodiment of the imaging apparatus of the present invention.

In the figure, reference numeral 100 denotes an imaging device, and for example, a frame transfer 1ccD as shown in the first diagram is used, but it may also be an MO8 type X-Y address sensor or an imaging tube.

10 is a driver circuit that supplies drive pulses necessary for scanning of this device 100, and 11 is a clock circuit that supplies clock pulses to the driver circuit 10. The output of the device 1 [) [) is inputted into the clamp pulse control circuit 13 according to the present invention after increasing the duty by the sample and hold circuit 12, and detects whether there is a defective signal during the optical black period. The clamp pulse supplied to the next-stage clamp circuit 20 is controlled in accordance with this detection output. In the clamp circuit 20, the pedestal level is DC-regenerated to the reference black level, and after being subjected to various corrections in the process circuit 25, the encoder 60
is input.

On the other hand, the output of the sample and hold circuit 12 is supplied to sample and hold circuits 14 to 16 for separating color signals, and each color signal component is extracted from the dot sequential signal at different timings.

The outputs of the sandal hold circuits 14 to 16 are connected to the circuit 16, respectively.
The signals are input to clamp pulse control circuits 17 to 19 having the same configuration as , and then DC-regenerated in clamp circuits 21 to 26, respectively.

The outputs of the clamp circuits 21 to 26 are connected to gross circuits 26, respectively.
~ 28, the signal is processed and sent to the white balance control circuit 2
After their levels are adjusted with each other in step 9, the signals are input to an encoder 60 and converted into a standard television signal such as an NTSG signal.

Figure 8 shows the clamp pulse control circuit 13゜17~ of the present invention.
19! This is a diagram showing an example of the sample and hold circuit 1.
The output of No. 2 is input to a defect signal detection circuit 161, and when a signal outside a predetermined level range is detected during the optical black period, a pulse signal is generated. Reference numeral 132 is a one-shot circuit for increasing the width of this pulse signal to some extent, and this provides a margin for preventing the clamp pulse described later from picking up a signal corresponding to a scratch in the optical black. It is. The output of this one-shot circuit 162 is supplied from the clock circuit 11, and the ninth
The clamping pulse, which is at a high level during the optical black period as shown in the figure, is logically multiplied by the analog signal 133 to form a rung pulse as shown in FIG. 961.

The output a of the ten-thousand pull-hold circuit 120 is delayed by delay circuits 1 to 4, and by matching the phases, it becomes as shown in Figure 9 a', and as shown in Figure 9 61, there is some width before and after the scratched part. The clamp can be stopped with .

With this configuration, correct direct current reproduction can be performed without being affected by scratches in the optical black portion.

Next, FIG. 10 (2L) is a diagram showing another example of the configuration related to the clamp circuit 20, and shows switching transistors ST1 to STn for aligning the output of the sandal hold circuit 12 shown in No. 7V4 to the potential of the capacitor 201. A plurality of transistors are provided as shown in FIG. 10, and these transistors are sequentially turned on by the clock circuit 11 via the transistors AN1 to ANn as shown in FIG.

The clamping operation is stopped by turning off the transistor (r) only while the output of the one-shot circuit 162 is at a high level.This configuration makes it suitable for engineering.

Further, FIG. 11 is a diagram showing the configuration of another embodiment of the present invention.
The same numbers as up to Figure io indicate the same elements.

62 is a detection circuit that outputs four types of pulses a to d as shown in FIG. 12 depending on the presence or absence and location of a scratch.

Further, 61 is a mode setting circuit which outputs four types of clamp pulses from mode 1 to mode 4 in FIG. 12 during the tail black period in accordance with the timing output of the clock circuit 11. The output mode of this mode setting circuit 61 is set to mode 1 according to the output states a - d of the detection circuit.
~mode 4 respectively.

Furthermore, with this configuration, the circuit for controlling the entire crank 7'' becomes extremely simple.

(Effects) As explained above, according to the present invention, even if there is a scratch on the optical blank portion of the imaging means, the petestal portion can be correctly clamped, so that the yield of the imaging means can be improved.

It goes without saying that the present invention is effective not only for two-dimensional imaging devices but also for one-dimensional imaging devices.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of an imaging device having a 2-butical black, Fig. 2 is a diagram showing -elJ of the relationship between the optical black and the clamp pulse, Fig. 6 is a diagram of the principle of the clamp circuit, and Fig. 4 is a diagram showing the relationship between the optical black and the clamp pulse. Figure 5 is a diagram showing the timing of clamping, Figure 5 is a diagram showing an example of a signal when there is a flaw in the optical blank section, Figure 6 is a diagram explaining the clamping error of alignment shown in Figure 5, Figure 7 is A diagram showing an example of the configuration of the imaging device of the present invention, FIG. 8 is a diagram showing an example of the configuration of the clamp control circuit of the present invention, FIG. 9 is an explanatory diagram of the operation of the circuit shown in the eighth diagram,
10(a) is a diagram showing -fll of the configuration of the clamp circuit and clamp control circuit of the present invention; FIG. 10(b) is an explanatory diagram of the clamp pulse in the configuration of FIG. 10(a);
1 is a diagram showing another example of the configuration of the clamp circuit and clamp control circuit of the present invention, and FIG. 12 is a diagram explaining the operation of the configuration shown in FIG. 11. ... Clamp circuit 13 ... Clamp control circuit 1 Ro 1 ... Detection circuit 2M No. 5 (Fig. 462-

Claims (1)

[Claims] an imaging means for converting an optical image into an electrical signal; a clamping means for clamping a predetermined portion of the output of the imaging means to a predetermined potential; a detection means for detecting a defect in the signal in the portion of the imaging means; An imaging device comprising: a clamp control means for controlling a clamping operation of the clamping means according to an output of the detection means.