Solid-state imaging device and method of operating solid-state imaging device

Abstract

A solid-state imaging device has: a photo-detection unit; a charge transfer unit transferring charges generated by the photo-detection unit in response to a first and a second clock generated by a clock supply circuit. The charge transfer unit includes: a first charge transfer element; a second charge transfer element adjacent to the first charge transfer element; and a charge transfer element group adjacent to the second charge transfer element and including a plurality of charge transfer elements. In a time period, the clock supply circuit supplies the first clock to the first charge transfer element, the second clock to the second charge transfer element, and constant potentials to respective the plurality of charge transfer elements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, advantages and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram showing a configuration of a conventional solid-state imaging device;

FIG. 2 is a block diagram showing an example of a configuration of a solid-state imaging device according to the present invention;

FIG. 3 is a cross-sectional view illustrating an example of a structure of a CCD of the solid-state imaging device;

FIG. 4 is a magnified view of the structure illustrated in FIG. 3;

FIG. 5 is a circuit diagram showing a clock supply circuit of the solid-state imaging device according to a first embodiment of the present invention;

FIG. 6 is a timing chart showing a time variation of potentials of signal lines;

FIG. 7 conceptually shows a charge transfer in the CCD according to the first embodiment;

FIG. 8 is a cross-sectional view showing electrode capacitances in the CCD;

FIG. 9 is a circuit diagram showing a clock supply circuit of the solid-state imaging device according to a second embodiment of the present invention;

FIG. 10 is a timing chart showing a time variation of potentials of signal lines in an intermediate resolution mode;

FIG. 11 conceptually shows a charge transfer in the intermediate resolution mode; and

FIG. 12 conceptually shows a charge transfer in a high resolution mode.

Claims

1. A solid-state imaging device comprising: a photo-detection unit configured to generate charges in response to a received light;a charge read-out unit configured to read said generated charges;a charge transfer unit configured to transfer said charges read by said charge read-out unit to a charge detection unit in response to a first clock and a second clock; anda clock supply circuit configured to generate said first clock and said second clock,wherein said charge transfer unit includes:a first charge transfer element;a second charge transfer element adjacent to said first charge transfer element; anda charge transfer element group adjacent to said second charge transfer element and including a plurality of charge transfer elements that are different from said first charge transfer element and said second charge transfer element,wherein in a first time period, said clock supply circuit supplies said first clock to said first charge transfer element, said second clock to said second charge transfer element, and constant potentials to respective said plurality of charge transfer elements.

2. The solid-state imaging device according to claim 1, wherein in a second time period following said first time period, said clock supply circuit supplies an inverted signal of a signal of said first clock during said first time period to said first charge transfer element, an inverted signal of a signal of said second clock during said first time period to said second charge transfer element, and said constant potentials to respective said plurality of charge transfer elements.

3. The solid-state imaging device according to claim 1, wherein said charge transfer unit further includes another first charge transfer element that is adjacent to said charge transfer element group and is different from said second charge transfer element.

4. The solid-state imaging device according to claim 3, wherein operation modes of the solid-state imaging device includes:a low resolution mode; anda high resolution mode in which resolution is higher than that in said low resolution mode,wherein in said low resolution mode, four charge transfer elements provided between said second charge transfer element and said another first charge element are said plurality of charge transfer elements.

5. The solid-state imaging device according to claim 4, wherein said operation modes further includes an intermediate resolution mode in which resolution is higher than that in said low resolution mode and lower than that in said high resolution mode,wherein in said intermediate resolution mode, two charge transfer elements provided between said second charge transfer element and said another first charge element are said plurality of charge transfer elements.

6. The solid-state imaging device according to claim 5, wherein said clock supply circuit has:a clock generating unit configured to generate said first clock and said second clock; anda resolution switch unit connected to said clock generating unit,wherein said resolution switch unit switches said operation modes in response to a control signal supplied from a control unit.

7. A method of operating a solid-state imaging device comprising: (a) generating a first clock and a second clock, wherein said second clock is an inversion clock of said first clock;(b) reading charges that are generated by a photo-detector in response to a received light and transferring said charges to a charge transfer unit; and(c) transferring said charges to a charge detection unit by said charge transfer unit in response to said first clock and said second clock,wherein said charge transfer unit includes:a first charge transfer element;a second charge transfer element adjacent to said first charge transfer element; anda charge transfer element group adjacent to said second charge transfer element and including a plurality of charge transfer elements that are different from said first charge transfer element and said second charge transfer element,wherein in a first time period, said (c) step includes:(c1) supplying said first clock to said first charge transfer element;(c2) supplying said second clock to said second charge transfer element; and(c3) supplying constant potentials to respective said plurality of charge transfer elements.

8. The method according to claim 7, wherein in a second time period following said first time period, said (c) step includes:(c4) supplying an inversed signal of a signal of said first clock during said first time period to said first charge transfer element;(c5) supplying an inversed signal of a signal of said second clock during said first time period to said second charge transfer element; and(c6) supplying said constant potentials to respective said plurality of charge transfer elements.

9. The method according to claim 7, wherein said charge transfer unit further includes another first charge transfer element that is adjacent to said charge transfer element group and is different from said second charge transfer element.

10. The method according to claim 9, wherein operation modes of the solid-state imaging device includes:a low resolution mode; anda high resolution mode in which resolution is higher than that in said low resolution mode,wherein in said low resolution mode, four charge transfer elements provided between said second charge transfer element and said another first charge element are said plurality of charge transfer elements.

11. The method according to claim 10, wherein said operation modes further includes an intermediate resolution mode in which resolution is higher than that in said low resolution mode and lower than that in said high resolution mode,wherein in said intermediate resolution mode, two charge transfer elements provided between said second charge transfer element and said another first charge element are said plurality of charge transfer elements.

12. A two-phase driving type solid-state imaging device comprising: a photo-detection unit having a plurality of photo detectors;a charge read-out unit configured to read charges generated by said plurality of photo detectors; anda charge transfer unit configured to transfer said charges read by said charge read-out unit,wherein said charge transfer unit is provided with a plurality of pairs of a storage electrode and a barrier electrode,wherein driving pulses of different phases are respectively applied to adjacent pairs of said plurality of pairs, and a driving pulse or a DC voltage is applied to a pair adjacent to said adjacent pairs of said plurality of pairs.

13. The two-phase driving type solid-state imaging device according to claim 12, wherein a number of pairs of said plurality of pairs to which said DC voltage is applied is an integral multiple of two.

14. The two-phase driving type solid-state imaging device according to claim 12, wherein when said charges are supplied from said charge read-out unit to said charge transfer unit, a voltage higher than said DC voltage is applied to said storage electrode to which said DC voltage is applied in said charge transfer.

15. The two-phase driving type solid-state imaging device according to claim 12, wherein an amplitude of said driving voltages applied to said adjacent pairs in a case when said DC voltage is applied to said pair is larger than that when said DC voltage is not applied to said pair.