Photoelectric conversion apparatus having reset noise holding and removing units

• US 6,538,693 B1
• Filed: 01/21/1997
• Issued: 03/25/2003
• Est. Priority Date: 01/24/1996
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kozuka, Hiraku
• Primary Examiner(s): HO, TUAN V
• Application Number:
  US08/786,183
• Time in Patent Office: 2,254 Days
• Field of Search: 348/241, 348/250, 348/302, 348/304, 348/308
• US Class Current: 348/241
• CPC Class Codes: H04N 25/65 applied to reset noise, e.g. KTC noise related to CMOS structures by techniques other than CDS

Abstract

In a one-dimensional or two-dimensional photoelectric converting apparatus for simultaneously executing an accumulation of a photosignal and an output of a signal, in order to remove a reset noise of a sensor unit and to reduce a random noise, the apparatus has a photosensor, a resetting circuit of the photosensor, noise signal holding elements for holding a noise signal when a resetting operation of the photosensor is executed, and a noise signal removing circuit for removing a noise from the signal accumulated in the photosensor after completion of the same resetting operation by using the noise signal held.

Claims

1. A photoelectric conversion apparatus, comprising:

photoelectric conversion circuit including a photo-receiving portion for receiving a photosignal from an object, converting the photosignal into an electric signal, and accumulating charges generated thereby;

reset circuit for resetting said photo-receiving portion;

noise signal holding circuit for holding reset noise caused when a resetting operation of said photo-receiving portion by said reset circuit is executed while the charges are being accumulated in said photo-receiving portion; and

noise signal removing circuit for performing a difference operation between a first signal and a second signal, wherein the first signal includes the reset noise held in said noise signal holding circuit, and the second signal includes the reset noise and a signal generated by receiving the photosignal in a first period after completion of the resetting operation, and wherein said noise signal removing circuit performs the difference operation while said photo-receiving portion accumulates the charges after a reset of said photo-receiving portion which is performed by said reset circuit after the signal generated by receiving the photosignal in said first period is read out from said photo-receiving portion.

2. An apparatus according to claim 1, wherein said noise signal holding circuit has at least an MOS transistor.

3. An apparatus according to claim 2, wherein said noise signal holding circuit is constructed by at least an MOS source follower and an MOS transistor switch.

4. An apparatus according to claim 3, wherein said noise signal holding circuit is constructed by at least an MOS sources follower, an MOS transistor switch, and a capacitor.

5. An apparatus according to claim 1, wherein said photoelectric conversion circuit has at least a photodiode and an MOS source follower.

6. An apparatus according to claim 5, wherein said photoelectric conversion circuit has at least a photodiode and an MOS source follower.

7. An apparatus according to claim 1, wherein at least parts of a photosignal accumulation period of time and a read-out period of time are simultaneously executed.

8. An apparatus according to claim 1, wherein said photoelectric conversion circuit, said noise signal holding circuit, and said noise signal removing circuit are formed on a same semiconductor substrate.

9. An apparatus according to claim 1, wherein said noise signal removing circuit further comprises:

first signal holding circuit for accumulating the first signal;

second signal holding circuit for accumulating the second signal; and

difference generation circuit for generating the difference signal between the first signal read out from said first signal holding circuit, and the second signal read out from said second signal holding circuit.

10. An apparatus according to claim 9, wherein said photoelectric conversion circuit, said reset circuit, said noise signal holding circuit, said first signal holding circuit, said second signal holding circuit and said difference generation difference generation circuit are formed on a same semiconductor substrate.

11. An apparatus according to claim 9, wherein the accumulation of the charges in said photo-receiving portion, and the reading out of the first and second signals respectively from said first and second signal holding circuit, are performed simultaneously in at least a portion of a period which starts after the resetting operation.

12. An apparatus according to claim 1, wherein said noise signal holding circuit is provided between said photoelectric conversion circuit and said noise signal removing circuit.

13. An apparatus according to claim 1, wherein said photoelectric conversion circuit and said reset circuit are arranged one-dimensionally or two-dimensionally.

14. An apparatus according to claim 1, wherein said noise signal holding circuit is arranged one-dimensionally or two-dimensionally.

15. A photoelectric conversion apparatus comprising:

a plurality of photoelectric conversion circuit, each of said photoelectric conversion circuit including a photo-receiving portion for receiving a photosignal from an object, converting the photosignal into an electric signal, and accumulating charges generated thereby;

reset circuit for supplying a reset level to said photo-receiving portion from an input side of a transfer transfer circuit;

noise signal holding circuit including a capacitor for holding reset noise caused when a resetting operation of said photo-receiving portion by said reset circuit is executed while the charges are being accumulated in said photo-receiving portion and transfer circuit for transferring the reset noise from the said photoelectric conversion circuit to said capacitor, wherein said reset circuit supplies said reset level to said photo-receiving portion from an input side of said transfer circuit; and

noise signal removing circuit performing a difference operation between a first signal and a second signal, wherein the first signal includes the reset noise held in said noise signal holding circuit, and the second signal includes the reset noise and a signal generated by receiving the photosignal in a first period after completion of the resetting operation, and wherein said noise signal removal circuit performs the difference operation while said photo-receiving portion accumulates the charges after a reset of said photo-receiving portion which is performed by said reset circuit after the signal generated by receiving the photosignal in said first period is read out from said photo-receiving portion.

16. An apparatus according to claim 15, wherein said noise signal holding circuit and said reset circuit are arranged in each of said plurality of photoelectric conversion circuit.

17. An apparatus according to claim 15, wherein said noise signal removing circuit further comprises:

first signal holding circuit for accumulating the first signal;

second signal holding circuit for accumulating the second signal; and

difference generation circuit for generating the difference signal between the first signal read out from said first signal holding circuit, and the second signal read out from said second signal holding circuit.

18. An apparatus according to claim 17, wherein the accumulation of the charges in said photo-receiving portion of said photoelectric conversion circuit, and the reading out of the first and second signals respectively from said first and second signal holding circuit, are performed simultaneously in at least a portion of a period which starts after the resetting operation.

19. An apparatus according to claim 15, wherein said noise signal holding circuit is provided between said photoelectric conversion circuit and said noise signal removing circuit.

20. An apparatus according to claim 15, wherein said plurality of photoelectric conversion circuit and said reset circuit are arranged one-dimensionally or two-dimensionally.

21. A photoelectric conversion apparatus comprising:

a plurality of photoelectric conversion circuit, each of said photoelectric conversion circuit including a photo-receiving portion for receiving a photosignal from an object, converting the photosignal into an electric signal, and accumulating charges generated thereby and amplifying circuit for amplifying a signal from said photo-receiving portion;

reset circuit for resetting said photo-receiving portion;

noise signal holding circuit for holding reset noise caused when a resetting operation of said photo-receiving portion by said reset circuit is executed while the charges are being accumulated in said photo-receiving portion, wherein said noise signal holding circuit holds a reset noise outputted from said amplifying circuit; and

noise signal removing circuit for performing a difference operation between a first signal and a second signal, wherein the first signal includes the reset noise held in said noise signal holding circuit, and the second signal includes the reset noise and a signal generated by receiving the photosignal in a first period after completion of the resetting operation, and wherein said noise signal removal circuit performs the difference operation while said photo-receiving portion accumulates the charges after a reset of said photo-receiving portion which is performed by said reset circuit after the signal generated by receiving the photosignal in said first period is read out from said photo-receiving portion.

22. An apparatus according to claim 21, wherein said amplifying circuit is a source follower circuit.

23. An apparatus according to claim 21, wherein said noise signal holding circuit and said reset circuit are arranged in each of said plurality of photoelectric conversion circuit.

24. An apparatus according to claim 21, wherein said noise signal removing circuit further comprises:

first signal holding circuit for accumulating the first signal;

second signal holding circuit for accumulating the second signal; and

difference generation circuit for generating the difference signal between the first signal read out from said first signal holding circuit, and the second signal read out from said second signal holding circuit.

25. An apparatus according to claim 24, wherein the accumulation of the charges in said photo-receiving portion of said photoelectric conversion circuit, and the reading out of the first and second signals respectively from said first and second signal holding circuit, are performed simultaneously in at least a portion of a period which starts after the resetting operation.

26. An apparatus according to claim 21, wherein said noise signal holding circuit is provided between said photoelectric conversion circuit and said noise signal removing circuit.

27. An apparatus according to claim 21, wherein said plurality of photoelectric conversion circuit and said reset circuit are arranged one-dimensionally.

28. An apparatus according to claim 21, wherein said plurality of photoelectric conversion circuit and said reset circuit are arranged two-dimensionally.

29. An apparatus according to claim 21, wherein said amplifying circuit includes an amplifying transistor whose control electrode area is connected to said photo-received portion without connection via a transistor.

30. An apparatus according to claim 29, wherein said amplifying circuit further includes a constant-current load, and wherein said constant-current load and said amplifying transistor form a source-follower circuit.

31. A photoelectric conversion apparatus comprising:

a plurality of photoelectric conversion units, each photoelectric conversion unit comprising;

a photoelectric conversion portion adapted to receive a photo-signal from an object, convert the received photo-signal into an electric signal, and accumulate photo-charge,

an amplifier transistor adapted to amplify a signal from said photoelectric conversion portion and output the amplified signal, and

a reset transistor adapted to supply a reset signal to said photoelectric conversion portion, wherein a control electrode area of said amplifier transistor is connected to said photoelectric conversion portion without connection via a transistor;

a plurality of first accumulation units arranged correspondingly to respective ones of said plurality of photoelectric conversion units and adapted to accumulate a signal from said photoelectric conversion portion of a respective one of said photoelectric conversion units, each accumulation unit comprising;

a switching transistor adapted to transfer the signal from the photoelectric conversion unit,

a capacitor adapted to accumulate the signal transferred through said switching transistor, and

a read-out transistor adapted to read out the signal accumulated in said capacitor;

a plurality of second accumulation units adapted to accumulate signals from said plurality of first accumulation units;

a common output line adapted to output sequentially the signals from said plurality of second accumulation units;

a drive circuit adapted to effect control so that during a time period in which the signals from said plurality of second accumulation units are output sequentially to said common output line, a signal which is generated due to reset of said photoelectric conversion portion at a first timing is stored in said capacitor of said first accumulation unit and accumulation of photo-charge is performed in said photoelectric conversion portion for a predetermined time, wherein the accumulation of photo-charge to be performed for the predetermined time is started when said photoelectric conversion portion is reset at the first timing; and

a differential circuit adapted to perform a differential processing between the signal from said first accumulation unit, which is generated due to the reset of said photoelectric conversion portion at the first timing, and a signal generated by accumulating the photo-charge in said photoelectric conversion portion for the predetermined time after the reset at the first timing.

32. An apparatus according to claim 31, wherein said read-out transistor amplifies a signal in said control electrode area and outputs the amplified signal from a main electrode area.

33. An apparatus according to claim 31, further comprising a constant-current load, wherein said constant-current load and said amplifier transistor form a source-follower circuit.

34. A photoelectric conversion apparatus comprising:

a plurality of photoelectric conversion units arranged two-dimensionally, each photoelectric conversion unit comprising;

a photoelectric conversion portion adapted to receive a photo-signal from an object, convert the received photo-signal into an electric signal, and accumulate photo-charge,

an amplifier transistor adapted to amplify a signal from said photoelectric conversion portion and output the amplified signal, and

a reset transistor adapted to supply a reset signal to said photoelectric conversion portion, wherein a control electrode area of said amplifier transistor is connected to said photoelectric conversion portion without connection via a transistor;

a plurality of first accumulation units arranged two-dimensionally and correspondingly to respective ones of said plurality of photoelectric conversion units, and adapted to accumulate a signal from said photoelectric conversion portion of a respective one of said photoelectric conversion units;

a plurality of second accumulation units adapted to accumulate signals from said plurality of first accumulation units;

a common output line adapted to output sequentially the signals from said plurality of second accumulation units;

a drive circuit adapted to effect control so that during a time period in which the signals from said plurality of second accumulation units are output sequentially to said common output line, a signal which is generated due to reset of said photoelectric conversion portion at a first timing is stored in a capacitor of said first accumulation unit and accumulation of photo-charge is performed in said photoelectric conversion portion for a predetermined time, wherein the accumulation of photo-charge to be performed for the predetermined time is started when said photoelectric conversion portion is reset at the first timing; and

a differential circuit adapted to perform a differential processing between the signal from said first accumulation unit, which is generated due to the reset of said photoelectric conversion portion at the first timing, and a signal generated by accumulating the photo-charge in said photoelectric conversion portion for the predetermined time after the reset at the first timing.

35. An apparatus according to claim 34, wherein each of said plurality of first accumulation units includes a read-out transistor adapted to amplify a signal in said control electrode area and output the amplified signal from a main electrode area.

36. An apparatus according to claim 34, further comprising a constant-current load, wherein said constant-current load and said amplifier transistor form a source-follower circuit.

37. An image pickup apparatus comprising:

a photo-converting cell including an amplifier for amplifying a signal generated in said photo-converting cell;

a drive circuit for resetting said photo-converting cell, then reading out a first noise signal from said photo-converting cell, then reading out a first image signal from said photo-converting cell, then resetting said photo-converting cell, then reading out a second noise signal, and then a second image signal from said photo-converting cell;

a first noise memory connected to said photo-converting cell for storing said second noise signal read out from said photo-converting cell; and

a noise removing circuit for removing said first noise signal from said first image signal, wherein said noise removing circuit includes a second noise memory for storing said first noise signal while said second noise signal is stored in said first noise memory.

38. An apparatus according to claim 37, wherein said drive circuit resets said photo-converting cells by resetting a control electrode of said amplifier.

39. An apparatus according to claim 37, wherein said first noise memory is selectively connected to said second noise memory.

40. An apparatus according to claim 39, wherein a noise signal in said first noise memory is selectively transferred to said second noise memory.

41. An image pickup apparatus comprising:

a photo-converting cell including an amplifier for amplifying a signal generated in said photo-converting cell;

a drive circuit for resetting said photo-converting cell, then reading out a first noise signal from said photo-converting cell, then reading out an image signal from said photo-converting cell;

a noise removing circuit for carrying out a noise removing operation to remove said first noise signal from said image signal, wherein said noise removing circuit includes a memory for storing said first noise signal;

a buffer memory connected to said photo-converting cell for storing a second noise signal read out from said photo-converting cell while said noise removing operation by said noise removing circuit is carried out.

42. An apparatus according to claim 41, wherein said drive circuit resets said photo-converting cell by resetting a control electrode of said amplifier.

43. An apparatus according to claim 41, wherein said buffer memory is selectively connected to said memory.

44. An apparatus according to claim 43, wherein said second noise signal in said buffer memory is selectively transferred to said memory.