IMAGING APPARATUS AND METHOD OF DRIVING SOLID-STATE IMAGING DEVICE

• US 20090086073A1
• Filed: 09/24/2008
• Published: 04/02/2009
• Est. Priority Date: 09/27/2007
• Status: Abandoned Application

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Kobayashi, Hirokazu
• Application Number:
  US12/236,911
• Publication Number:
  US 20090086073A1
• Time in Patent Office: Days
• US Class Current: 348/302
• CPC Class Codes: H04N 25/585 with pixels having different sensitivities within the sensor, e.g. fast or slow pixels or pixels having different sizes
• CPC Class Codes: H04N 25/626 Reduction of noise due to residual charges remaining after image readout, e.g. to remove ghost images or afterimages

Abstract

A solid-state imaging device 5 includes photoelectric conversion elements 51R, 51G, and 51B and photoelectric conversion elements 51r, 51g, and 51b there are controlled to have an exposure time shorter than that of the photoelectric conversion elements 51R, 51G, and 51B. During the exposure period of the photoelectric conversion elements 51R, 51G, and 51B, an imaging device driving section 10 applies a readout pulse to transfer electrodes V2 and V6 and applies a suppression pulse having a polarity opposite to that of the readout pulse to transfer electrodes V4 and V8, to thereby read out the charges stored in the photoelectric conversion elements 51r, 51g, and 51b to a vertical charge transfer path 54 and to control start of exposure of the photoelectric conversion elements 51r, 51g, and 51b.

Claims

1. An imaging apparatus comprising:

a solid-state imaging device; and

a driving unit that drives the solid-state imaging device, wherein

the solid-state imaging device includes;

a plurality of photoelectric conversion elements that are two-dimensionally arranged on a semiconductor substrate in a specific direction and a direction that is orthogonal to the specific direction,

a plurality of charge transfer paths that are provided so as to correspond to photoelectric conversion element columns, each including the photoelectric conversion elements arranged in the specific direction, the charge transfer paths that transfer in the specific direction charges generated in the plurality of photoelectric conversion elements, and

transfer electrodes that are provided above the charge transfer paths and are arranged along the specific direction,

the transfer electrodes include first transfer electrodes that are provided to correspond to the respective photoelectric conversion elements constituting the photoelectric conversion element column, the first transfer electrodes that control reading out of the charges from the photoelectric conversion elements to the charge transfer paths and the transferring of the charges in the charge transfer path,

the plurality of photoelectric conversion elements include first photoelectric conversion elements and second photoelectric conversion elements,

an exposure time of the second photoelectric conversion elements is shorter than that of the first photoelectric conversion elements, and

during the exposure period of the first photoelectric conversion elements, the driving unit performs a driving operation including

applying, to the first transfer electrodes corresponding to the second photoelectric conversion elements, a readout pulse for reading out the charges stored in the photoelectric conversion elements to the charge transfer paths, and

applying, to at least a part of the transfer electrodes other than the transfer electrode to which the readout pulse is applied, a suppression pulse that has a polarity opposite to that of the readout pulse and prevents potentials of charge storage regions of the photoelectric conversion elements from changing due to the readout pulse.

2. The imaging apparatus according to claim 1, wherein

when the exposure time of the second photoelectric conversion elements is equal to or shorter than a threshold value, the driving unit performs the driving operation, and

when the exposure time of the second photoelectric conversion elements is longer than the threshold value, the driving unit classifies the first transfer electrodes corresponding to the second photoelectric conversion elements into a plurality of groups and applies the readout pulse and the suppression pulse to the plurality of groups at different timings.

3. The imaging apparatus according to claim 1, wherein

when the exposure time of the second photoelectric conversion elements is longer than a threshold value, the driving unit classifies the first transfer electrodes corresponding to the second photoelectric conversion elements into a plurality of groups and applies the readout pulse and the suppression pulse to the plurality of groups at different timings, and

when the exposure time of the second photoelectric conversion elements is equal to or shorter than the threshold value, the driving unit stops the applying of the suppression pulse during the driving operation and sets a level of the readout pulse to be higher than that of the readout pulse, which is applied when the exposure time of the second photoelectric conversion elements is longer than the threshold value.

4. The imaging apparatus according to claim 1, wherein a timing at which it is started to apply the suppression pulse matches a timing at which it is started to apply the readout pulse.

5. The imaging apparatus according to claim 1, wherein

applicable to each transfer electrode are a first transfer pulse, which has a level that is lower than that of the readout pulse and forms a packet for storing the charge in each charge transfer path, and a second transfer pulse, which has a level that is lower than that of the first transfer pulse and forms a barrier against the packet in each charge transfer path, and

the driving unit applies the second transfer pulse to all the transfer electrodes during at least a portion of a period from a start of the exposure time of the first photoelectric conversion elements to the applying of the readout pulse.

6. An imaging apparatus comprising:

a solid-state imaging device; and

a driving unit that drives the solid-state imaging device, wherein

the solid-state imaging device includes;

a plurality of photoelectric conversion elements that are two-dimensionally arranged on a semiconductor substrate in a specific direction and a direction that is orthogonal to the specific direction,

a plurality of charge transfer paths that are provided so as to correspond to photoelectric conversion element columns, each including the photoelectric conversion elements arranged in the specific direction, the charge transfer paths that transfer in the specific direction charges generated in the plurality of photoelectric conversion elements, and

transfer electrodes that are provided above the charge transfer paths and are arranged along the specific direction,

the transfer electrodes include first transfer electrodes that are provided to correspond to the respective photoelectric conversion elements constituting the photoelectric conversion element column, the first transfer electrodes that control reading out of the charges from the photoelectric conversion elements to the charge transfer paths and the transferring of the charges in the charge transfer path,

the plurality of photoelectric conversion elements include first photoelectric conversion elements and second photoelectric conversion elements,

an exposure time of the second photoelectric conversion elements is shorter than that of the first photoelectric conversion elements,

when the exposure time of the second photoelectric conversion elements is longer than a threshold value, during the exposure period of the first photoelectric conversion elements, the driving unit classifies the first transfer electrodes corresponding to the second photoelectric conversion elements into a plurality of groups and applies a first readout pulse for reading out the charges stored in the photoelectric conversion elements to the charge transfer paths to the plurality of groups at different timings, and

when the exposure time of the second photoelectric conversion elements is equal to or shorter than the threshold value, during the exposure period of the first photoelectric conversion elements, the driving unit applies a second readout pulse having a level that is higher than that of the first readout pulse to the first transfer electrodes corresponding to the second photoelectric conversion elements.

7. The imaging apparatus according to claim 6, wherein

applicable to each transfer electrode are a first transfer pulse, which has a level that is lower than that of the readout pulse and forms a packet for storing the charge in each charge transfer path, and a second transfer pulse, which has a level that is lower than that of the first transfer pulse and forms a barrier against the packet in each charge transfer path, and

the driving unit applies the second transfer pulse to all the transfer electrodes during at least a portion of a period from a start of the exposure time of the first photoelectric conversion elements to the applying of the readout pulse.

8. A method of driving a solid-state imaging device, wherein

the solid-state imaging device includes

a plurality of photoelectric conversion elements that are two-dimensionally arranged on a semiconductor substrate in a specific direction and a direction that is orthogonal to the specific direction,

a plurality of charge transfer paths that are provided so as to correspond to photoelectric conversion element columns, each including the photoelectric conversion elements arranged in the specific direction, the charge transfer paths that transfer in the specific direction charges generated in the plurality of photoelectric conversion elements, and

transfer electrodes that are provided above the charge transfer paths and are arranged along the specific direction,

the transfer electrodes include first transfer electrodes that are provided to correspond to the respective photoelectric conversion elements constituting the photoelectric conversion element column, the first transfer electrodes that control reading out of the charges from the photoelectric conversion elements to the charge transfer paths and the transferring of the charges in the charge transfer path,

the plurality of photoelectric conversion elements include first photoelectric conversion elements and second photoelectric conversion elements, and

an exposure time of the second photoelectric conversion elements is shorter than that of the first photoelectric conversion elements,

the method comprising

during the exposure period of the first photoelectric conversion elements, applying, to the first transfer electrodes corresponding to the second photoelectric conversion elements, a readout pulse for reading out the charges stored in the photoelectric conversion elements to the charge transfer paths, and applying, to at least a part of the transfer electrodes other than the transfer electrode to which the readout pulse is applied, a suppression pulse that has a polarity opposite to that of the readout pulse and prevents potentials of charge storage regions of the photoelectric conversion elements from changing due to the readout pulse.

9. The method according to claim 8, further comprising:

comparing the exposure time of the second photoelectric conversion elements with a threshold value, wherein

when the exposure time of the second photoelectric conversion elements is equal to or shorter than the threshold value, the applying of the readout pulse and the applying of the suppression pulse are performed, and

when the exposure time of the second photoelectric conversion elements is longer than the threshold value, the first transfer electrodes corresponding to the second photoelectric conversion elements are classified into a plurality of groups, and the readout pulse and the suppression pulse are applied to the plurality of groups at different timings.

10. The method according to claim 8, further comprising:

comparing the exposure time of the second photoelectric conversion elements with a threshold value, wherein

when the exposure time of the second photoelectric conversion elements is longer than the threshold value, the first transfer electrodes corresponding to the second photoelectric conversion elements are classified into a plurality of groups, and the readout pulse and the suppression pulse are applied to the plurality of groups at different timings, and

when the exposure time of the second photoelectric conversion elements is equal to or shorter than the threshold value, the applying of the suppression pulse is stopped, and a level of the readout pulse is set to be higher than that of the readout pulse, which is applied when the exposure time of the second photoelectric conversion elements is longer than the threshold value.

11. The method according to claim 8, wherein a timing at which it is started to apply the suppression pulse matches a timing at which it is started to apply the readout pulse.

12. The method according to claim 8, wherein

applicable to each transfer electrode are a first transfer pulse, which has a level that is lower than that of the readout pulse and forms a packet for storing the charge in each charge transfer path, and a second transfer pulse, which has a level that is lower than that of the first transfer pulse and forms a barrier against the packet in each charge transfer path,

the method further comprising:

applying the second transfer pulse to all the transfer electrodes during at least a portion of a period from a start of the exposure time of the first photoelectric conversion elements to the applying of the readout pulse.

13. A method of driving a solid-state imaging device, wherein

the solid-state imaging device includes:

a plurality of photoelectric conversion elements that are two-dimensionally arranged on a semiconductor substrate in a specific direction and a direction that is orthogonal to the specific direction,

a plurality of charge transfer paths that are provided so as to correspond to photoelectric conversion element columns, each including the photoelectric conversion elements arranged in the specific direction, the charge transfer paths that transfer in the specific direction charges generated in the plurality of photoelectric conversion elements, and

transfer electrodes that are provided above the charge transfer paths and are arranged along the specific direction,

the transfer electrodes include first transfer electrodes that are provided to correspond to the respective photoelectric conversion elements constituting the photoelectric conversion element column, the first transfer electrodes that control reading out of the charges from the photoelectric conversion elements to the charge transfer paths and the transferring of the charges in the charge transfer path,

the plurality of photoelectric conversion elements include first photoelectric conversion elements and second photoelectric conversion elements,

an exposure time of the second photoelectric conversion elements is shorter than that of the first photoelectric conversion elements,

the method comprising;

comparing the exposure time of the second photoelectric conversion elements with a threshold value;

when the exposure time of the second photoelectric conversion elements is longer than the threshold value, during the exposure period of the first photoelectric conversion elements, classifying the first transfer electrodes corresponding to the second photoelectric conversion elements into a plurality of groups, and applying a first readout pulse for reading out the charges stored in the photoelectric conversion elements to the charge transfer paths to the plurality of groups at different timings; and

when the exposure time of the second photoelectric conversion elements is equal to or shorter than the threshold value, during the exposure period of the first photoelectric conversion elements, applying a second readout pulse having a level that is higher than that of the first readout pulse to the first transfer electrodes corresponding to the second photoelectric conversion elements.

14. The method according to claim 13, wherein

applicable to each transfer electrode are a first transfer pulse, which has a level that is lower than that of the readout pulse and forms a packet for storing the charge in each charge transfer path, and a second transfer pulse, which has a level that is lower than that of the first transfer pulse and forms a barrier against the packet in each charge transfer path,

the method further comprising:

applying the second transfer pulse to all the transfer electrodes during at least a portion of a period from a start of the exposure time of the first photoelectric conversion elements to the applying of the readout pulse.