SOLID-STATE IMAGING DEVICE

Abstract

A solid-state imaging device which can, in response to the problem of black-crush occurring in an image when strong light is enters the device, positively detect black-crush in a state in which a variance margin has been secured. The solid-state imaging device outputs a luminance signal in accordance with an amount of received light, and includes: a pixel circuit having a light-receiving element; a signal output circuit having a sampling transistor which outputs, from a second signal output line, a luminance signal in accordance with the amount of light received by the light-receiving element, based on an output signal from the pixel circuit; and a high-intensity judgment circuit which is coupled by the pixel circuit and a judgment input coupling capacitor, judges whether or not light entering the light-receiving element is of high intensity based on the output signal from the pixel circuit, and in the case of judging the entering light to be of high intensity, outputs a luminance signal indicating high intensity.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings that illustrate a specific embodiment of the invention. In the Drawings:

FIG. 1 is a diagram showing an overall configuration of a solid-state imaging device according to the first through fifth embodiments of the present invention;

FIG. 2 is a detailed schematic of a solid-state imaging device according to the first embodiment of the present invention;

FIG. 3 is a diagram showing timings of control pulses in the solid-state imaging device;

FIG. 4 is a diagram showing signal waveforms occurring in the principle areas of the solid-state imaging device;

FIG. 5 is a diagram showing another example of timings of control pulses in the solid-state imaging device;

FIG. 6 is a detailed schematic of a solid-state imaging device according to the second embodiment of the present invention;

FIG. 7 is a diagram showing timings of control pulses in the solid-state imaging device;

FIG. 8 is a diagram showing signal waveforms occurring in the principle areas of the solid-state imaging device;

FIG. 9 is a detailed schematic of a solid-state imaging device according to the third embodiment of the present invention;

FIG. 10 is a diagram showing timings of control pulses in the solid-state imaging device;

FIG. 11 is a diagram showing signal waveforms occurring in the principle areas of the solid-state imaging device;

FIG. 12 is a detailed schematic of a solid-state imaging device according to the fourth embodiment of the present invention;

FIG. 13 is a diagram showing timings of control pulses in the solid-state imaging device;

FIG. 14 is a diagram showing signal waveforms occurring in the principle areas of the solid-state imaging device;

FIG. 15 is a detailed schematic of a solid-state imaging device according to the fifth embodiment of the present invention;

FIG. 16 is a schematic showing another example of an imaging circuit.

FIG. 17 is a schematic showing yet another example of an imaging circuit; and

FIG. 18 is a block diagram showing a configuration of an imaging camera according to the present invention.

Claims

1. A solid-state imaging device which outputs a luminance signal in accordance with an amount of light entering said device, said device comprising: an imaging unit in which plural pixel circuits are arranged one- or two-dimensionally, each pixel circuit including a photoelectric conversion unit, and each pixel circuit outputting a reset voltage and a read voltage, the reset voltage being a voltage generated when said photoelectric conversion unit is reset, and the read voltage being a voltage generated through photoelectric conversion being performed by said photoelectric conversion unit;a first signal output line which is connected to a number of said pixel circuits and which carries the reset voltage and read voltage outputted from said pixel circuits;a signal output circuit connected to said first signal output line and which outputs, from a second signal output line, a luminance signal in accordance with an amount of light received by said photoelectric conversion unit, based on the reset voltage and read voltage outputted to said first signal output line; anda high-intensity judgment circuit connected to said first signal output line via a first capacitor, which judges whether or not light entering said photoelectric conversion unit is of high intensity based on a voltage signal in said first signal output line, and, upon judging entering light of high intensity, outputs a luminance signal indicating high intensity to said second signal output line.

2. The solid-state imaging device according to claim 1, wherein said intensity judgment circuit judges whether or not the entering light is of high intensity based on the AC component of the voltage signal in said first signal output line.

3. The solid-state imaging device according to claim 1, wherein said intensity judgment circuit judges whether or not the entering light is of high intensity during a period in which said photoelectric conversion unit is reset or immediately after said photoelectric conversion unit has been reset.

4. The solid-state imaging device according to claim 1, wherein said intensity judgment circuit includes:a judgment input line, which is a signal line connected to said first capacitor;a second capacitor, one end of which is connected to said judgment input line; anda bias voltage adding circuit connected to the other end of said second capacitor and which adds a constant voltage to said judgment input line via said second capacitor, andsaid intensity judgment circuit judges whether or not the entering light is of high intensity by comparing a voltage at said judgment input line with a constant threshold value after the certain voltage has been added.

5. The solid-state imaging device according to claim 1, wherein said intensity judgment circuit includes:a judgment input line, which is a signal line connected to one end of said first capacitor;a second capacitor, one end of which is connected to the other end of said first capacitor; anda bias voltage adding circuit connected to the other end of said second capacitor and which adds a constant voltage to said judgment input line via said second capacitor, andsaid intensity judgment circuit judges whether or not the entering light is of high intensity by comparing a voltage in said judgment input line with a constant threshold value after the constant voltage has been added.

6. The solid-state imaging device according to claim 1, wherein said intensity judgment circuit is connected to said first capacitor, and includes a first switch transistor which closes or opens the connection between said first signal output line and said intensity judgment circuit via said first capacitor.

7. The solid-state imaging device according to claim 6, wherein said first switch transistor cuts the connection so as not to transfer fluctuation in a voltage signal in said first signal output line and in a voltage signal in the input stage of said intensity judgment circuit.

8. The solid-state imaging device according to claim 1, wherein said intensity judgment circuit judges whether or not the difference between the reset voltage and the read voltage outputted to said first signal output line is within a predetermined range, and judges that the entering light is of high intensity in the case where the difference is judged not to be within the predetermined range.

9. The solid-state imaging device according to claim 8, wherein the predetermined range is a range which includes the voltage signal outputted to said intensity judgment circuit when light of a maximum intensity enters said pixel circuits, and is a range smaller than the dynamic range of the voltage signal outputted from said pixel circuits to said intensity judgment circuit.

10. The solid-state imaging device according to claim 1, wherein said intensity judgment circuit includes:a judgment output circuit which outputs, to said second signal output line, a voltage of the same polarity as and a saturation greater than or equal to the luminance signal outputted from said signal output circuit to said second signal output line, in the case where the entering light is judged to be of high intensity.

11. The solid-state imaging device according to claim 1, wherein said intensity judgment circuit includes:a judgment input line, which is a signal line connected to said first capacitor; anda judgment amplification circuit which judges whether or not the entering light is of high intensity based on a voltage signal at said judgment input line, and which amplifies the voltage signal at said judgment input line and outputs the signal obtained through the amplification as a signal indicating a result of the judgment.

12. The solid-state imaging device according to claim 1, wherein said intensity judgment circuit judges whether or not the entering light is of high intensity during i) an interval from when said photoelectric conversion unit outputs the reset voltage to said first signal output line to when said photoelectric conversion unit outputs the read voltage to said first signal output line or ii) an interval from when said photoelectric conversion unit outputs the read voltage to when said photoelectric conversion unit outputs the reset voltage in the next imaging period, and outputs the luminance signal indicating that the entering light is of high intensity.

13. A camera, comprising the solid-state imaging device according to claim 1.

14. A driving method for a solid-state imaging device which outputs a luminance signal in accordance with an amount of received light, said method comprising: judging whether or not light entering a photoelectric conversion unit is of high intensity based on the AC component of an output signal from a pixel circuit which includes the photoelectric conversion unit; andoutputting, to a signal output line that outputs the luminance signal in accordance with an amount of received light, a luminance signal indicating the entering light is of high intensity, in the case where the entering light is judged to be of high intensity.

15. The driving method according to claim 14, wherein in said judging, resetting of the photoelectric conversion unit for said judging is performed in advance at a timing later than resetting for photoelectric conversion.