Light detection device, imaging device and distant image acquisition device

• US 7,193,197 B2
• Filed: 12/05/2002
• Issued: 03/20/2007
• Est. Priority Date: 12/05/2001
• Status: Active Grant

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Toyoda, Haruyoshi, Mizuno, Seiichiro, Sugiyama, Yukinobu, Mukozaka, Naohisa
• Primary Examiner(s): Epps; Georgia
• Assistant Examiner(s): WILLIAMS, DON J
• Application Number:
  US10/472,142
• Publication Number:
  US 20040195490A1
• Time in Patent Office: 1,566 Days
• Field of Search: 250/208.1, 250/214.1, 348/302, 348/304, 348/307, 348/309, 348/310, 348/290, 348/308, 348/241, 348/278, 257/465, 257/443
• US Class Current: 250/208.1
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• 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 25/767 Horizontal readout lines, multiplexers or registers
• CPC Class Codes: H04N 3/1506 with addressing of the image-sensor elements H04N3/1575 takes precedence

Abstract

A photosensitive region includes a semiconductor substrate 40 made of a P-type semiconductor, and N-type semiconductor regions 41 and 42 formed on the surface of the semiconductor substrate 40. Accordingly, each photosensitive portion includes a portion of the semiconductor substrate 40 and a pair of the regions 41 and 42, thus configuring a photodiode. Each of the regions 41 and 42 is in a shape of an approximate triangle, and is formed so that one side of the regions 41 is adjacent to one side of the region 42, and vice versa, in one pixel. A first wire 44 is for electrically connecting the regions 41 on one side in each pixel across a first direction, and is provided extending in the first direction between the pixels. The second wire 47 is for electrically connecting the regions 47 on the other side in each pixel across a second direction, and is provided extending in the second direction between the pixels.

Claims

1. A photodetector in which a photosensitive region has pixels in a two-dimensional array,

wherein one pixel is configured by disposing a plurality of photosensitive portions adjacent to each other in one plane, each of the plurality of photosensitive portions outputting an electric current corresponding to an intensity of light incident on each of the photosensitive portions;

the photosensitive portions on one side, amongst the plurality of photosensitive portions configuring each of the pixels, are electrically connected to each other by one wiring across the plurality of pixels arrayed in a first direction in the two-dimensional array, and the wiring electrically connected to the photosensitive portions on one side transmits the electric currents outputted from the photosensitive portions on one side in the first direction; and

the photosensitive portions on the other side, amongst the plurality of photosensitive portions configuring each of the pixels, are electrically connected to each other by one wiring across the plurality of pixels arrayed in a second direction in the two-dimensional array, and the wiring electrically connected to the photosensitive portions on the other side transmits the electric currents outputted from the photosensitive portions on the other side in the second direction.

2. The photodetector according to claim 1, wherein each of the photosensitive portions includes a semiconductor substrate portion made of a first conductive type semiconductor, and a second conductive type semiconductor region formed in the semiconductor substrate portion, and

the second conductive type semiconductor region is in a shape of an approximate triangle when viewed from a light incident direction, the approximate triangle being formed so that one side thereof is adjacent to one side of another approximate triangle in the pixel.

3. The photodetector according to claim 1,

wherein each of the photosensitive portions includes a semiconductor substrate portion made of a first conductive type semiconductor, and a second conductive type semiconductor region formed in the semiconductor substrate portion, and

the second conductive type semiconductor region is in a shape of an approximate rectangle when viewed from a light incident direction, the approximate rectangle being formed so that a long side thereof is adjacent to a long side of another approximate rectangle in the pixel.

4. The photodetector according to claim 1,

wherein the wiring is provided for electrically connecting the photosensitive portions on one side to each other across the plurality of pixels arrayed in the first direction, the wiring extending in the first direction between the pixels, and

the wiring is provided for electrically connecting the photosensitive portions on the other side to each other across the plurality of pixels arrayed in the second direction, the wiring extending in the second direction between the pixels.

5. The photodetector according to claim 1,

wherein each of the photosensitive portions includes a semiconductor substrate portion made of a first conductive type semiconductor, and a second conductive type semiconductor region formed in the semiconductor substrate portion;

the second conductive type semiconductor region is divided into four parts in one pixel, and the wiring for electrically connecting the photosensitive portions on one side to each other across the plurality of pixels arrayed in the first direction and the wiring for electrically connecting the photosensitive portions on the other side to each other across the plurality of pixels arrayed in the second direction are provided in boundaries between the divided parts; and

in the second conductive type semiconductor region divided into four parts in the pixel, the divided parts in a diagonal relationship are connected by the wiring.

6. The photodetector according to claim 1,

wherein each of the photosensitive portions includes a semiconductor substrate portion made of a first conductive type semiconductor, and a second conductive type semiconductor region formed in the semiconductor substrate portion, and

the second conductive type semiconductor region is in a shape of a polygon with four or more angles when viewed from a light incident direction, the polygon being formed so that one side thereof is adjacent to one side of another polygon in the pixel.

7. The photodetector according to claim 6,

wherein the second conductive type semiconductor region of the photosensitive portion on one side and the second conductive type semiconductor region of the photosensitive portion on the other side are placed in rows within one pixel in the third direction which intersects the first and second directions.

8. The photodetector according to claim 6, wherein the second conductive type semiconductor regions are arrayed in a honeycomb structure when viewed from the light incident direction.

9. The photodetector according to claim 1, further comprising:

a first shift register for sequentially reading electric currents in the second direction, the electric currents being from groups of the photosensitive portions on one side which are electrically connected across the plurality of pixels arrayed in the first direction;

a second shift register for sequentially reading electric currents in the first direction, the electric currents being from groups of the photosensitive portions on the other side which are electrically connected across the plurality of pixels arrayed in the second direction;

a first integrating circuit which sequentially inputs the electric currents from each of the groups of photosensitive portions on one side, the electric currents being sequentially read by the first shift register, and converts the electric currents into voltages; and

a second integrating circuit which sequentially inputs the electric currents from each of the groups of photosensitive portions on the other side, the electric currents being sequentially read by the second shift register, and converts the electric currents into voltages.

10. The photodetector according to claim 1, further comprising:

first integrating circuits which are provided corresponding to groups of the photosensitive portions on one side which are electrically connected across the plurality of pixels arrayed in the first direction, convert electric currents from the corresponding groups of the photosensitive portions on one side into voltages, and then output voltages;

first CDS circuits which are provided corresponding to the first integrating circuits, and output voltages with values defined according to variations in the voltages outputted from the corresponding first integrating circuits;

first sample-and-hold circuits which are provided corresponding to the first CDS circuits, and hold and output the voltages from the corresponding first CDS circuits;

a first maximum value detecting circuit which detects maximum values of the voltages from each of the first sample-and-hold circuits;

a first A/D conversion circuit which sequentially inputs the voltages from each of the first sample-and-hold circuits, converts the voltages into digital values based on the maximum values detected by the first maximum value detecting circuit, and outputs the digital values;

second integrating circuits which are provided corresponding to groups of the photosensitive portions on the other side which are electrically connected across the plurality of pixels arrayed in the second direction, convert electric currents from the corresponding groups of the photosensitive portions on the other side into voltages, and then output voltages;

second CDS circuits which are provided corresponding to the second integrating circuits, and output voltages with values defined according to variations in the voltages outputted from the corresponding second integrating circuits;

second sample-and-hold circuits which are provided corresponding to the second CDS circuits, and hold and output the voltages from the corresponding second CDS circuits;

a second maximum value detecting circuit which detects maximum values of the voltages from each of the second sample-and-hold circuits; and

a second A/D conversion circuit which sequentially inputs the voltages from each of the second sample-and-hold circuits, converts the voltages into digital values based on the maximum values detected by the second maximum value detecting circuit, and outputs the digital values.

19. An imaging device,

wherein the photodetectors according to any one of claims 1 and 11 are provided in a two-dimensional array.

20. The imaging device according to claim 19,

wherein each of groups of the photodetectors, having a plurality of the photodetectors arranged in the second direction in the two-dimensional array, further includes:

a first shift register for sequentially reading electric currents in the second direction, the electric currents being from groups of the photosensitive portions on one side which are electrically connected across the plurality of pixels arrayed in the first direction; and

first integrating circuits which are provided for the respective groups of photodetectors having the plurality of photodetectors arranged in the second direction, and sequentially input the electric currents from each of the groups of photosensitive portions on one side, the electric currents being sequentially read by the first shift register, and convert the electric currents into voltages, and

wherein each of groups of the photodetectors, having a plurality of the photodetectors arranged in the first direction in the two-dimensional array, further includes;

a second shift register for sequentially sensing electric currents in the first direction, the electric currents being from groups of the photosensitive portions on the other side which are electrically connected across the plurality of pixels arrayed in the second direction; and

second integrating circuits which are provided for the respective groups of photodetectors having the plurality of photodetectors arranged in the first direction, and sequentially input the electric currents from each of the groups of photosensitive portions on the other side, the electric currents being sequentially read by the second shift register, and convert the electric currents into voltages.

21. A range image capture device, wherein a pair of the imaging devices according to claim 20 is arranged at a predetermined interval, the range image capture device comprising:

parallax amount determining means for determining an amount of parallax per each of the photodetectors based on the voltages from the first integrating circuits and the second integrating circuits;

distance operation means for operating a distance to an object from each of the photodetectors based on the amount of parallax determined by the parallax amount determining means; and

range image generating means for generating a range image based on the distance operated by the distance operation means.

11. A photodetector having photosensitive region,

wherein the photosensitive region includes a plurality of first photosensitive portions electrically connected to each other by one wiring across a first direction and a plurality of second photosensitive portions electrically connected to each other by one wiring across a second direction which intersects the first direction, and

the plurality of first photosensitive portions and the plurality of second photosensitive portions are arrayed to be two-dimensionally mixed within one plane,

wherein the wiring electrically connected to the plurality of first photosensitive portions transmits the electric currents outputted from the plurality of first photosensitive portions corresponding to an intensity of light incident in the first direction, and

the wiring electrically connected to the plurality of second photosensitive portions transmits electric currents outputted from the plurality of second photosensitive portions corresponding to an intensity of light incident in the second direction.

12. The photodetector according to claim 11, wherein the plurality of first photosensitive portions and the plurality of second photosensitive portions are alternately arrayed in any one of the first direction and the second direction.

13. The photodetector according to claim 11, wherein the plurality of first photosensitive portions and the plurality of second photosensitive portions are alternately arrayed in a third direction which intersects the first direction and the second direction.

14. The photodetector according to claim 13, wherein each of the photosensitive portions is arrayed in a honeycomb structure when viewed from a light incident direction.

15. The photodetector according to claim 11,

wherein each of the photosensitive portions includes a semiconductor substrate portion made of a first conductive type semiconductor, and a second conductive type semiconductor region formed in the semiconductor substrate portion, and

the second conductive type semiconductor region is in a shape of an approximate polygon when viewed from a light incident direction, the approximate polygon being formed so that one side thereof is adjacent to one side of another approximate polygon.

16. The photodetector according to claim 11,

wherein the wiring is provided for electrically connecting the first photosensitive portions to each other, the wiring extending in the first direction between the respective photosensitive portions, and

the wiring is provided for electrically connecting the second photosensitive portions to each other, the wiring extending in the second direction between the respective photosensitive portions.

17. The photodetector according to claim 11, further comprising:

a first shift register for sequentially reading electric currents in the second direction, the electric currents being from groups of the first photosensitive portions which are electrically connected to each other across the first direction;

a second shift register for sequentially reading electric currents in the first direction, the electric currents being from groups of the second photosensitive portions which are electrically connected to each other across the second direction;

a first integrating circuit which sequentially inputs the electric currents from each of the groups of first photosensitive portions, the electric currents being sequentially read by the first shift register, and converts the electric currents into voltages; and

a second integrating circuit which sequentially inputs the electric currents from each of the groups of second photosensitive portions, the electric currents being sequentially read by the second shift register, and converts the electric currents into voltages.

18. The photodetector according to claim 11, further comprising:

first integrating circuits which are provided corresponding to groups of the first photosensitive portions which are electrically connected to each other across the first direction, convert electric currents from the corresponding groups of the first photosensitive portions into voltages, and then output voltages;

first CDS circuits which are provided corresponding to the first integrating circuits, and output voltages with values defined according to variations in the voltages outputted from the corresponding first integrating circuits;

first sample-and-hold circuits which are provided corresponding to the first CDS circuits, and hold and output the voltages from the corresponding first CDS circuits;

a first maximum value detecting circuit which detects maximum values of the voltages from each of the first sample-and-hold circuits;

a first A/D conversion circuit which sequentially inputs the voltages from each of the first sample-and-hold circuits, converts the voltages into digital values based on the maximum values detected by the first maximum value detecting circuit, and outputs the digital values;

second integrating circuits which are provided corresponding to groups of the second photosensitive portions which are electrically connected to each other across the second direction, convert electric currents from the corresponding groups of the second photosensitive portions into voltages, and then output voltages;

second CDS circuits which are provided corresponding to the second integrating circuits, and output voltages with values defined according to variations in the voltages outputted from the corresponding second integrating circuits;

second sample-and-hold circuits which are provided corresponding to the second CDS circuits, and hold and output the voltages from the corresponding second CDS circuits;

a second maximum value detecting circuit which detects maximum values of the voltages from each of the second sample-and-hold circuits; and

a second A/D conversion circuit which sequentially inputs the voltages from each of the second sample-and-hold circuits, converts the voltages into digital values based on the maximum values detected by the second maximum value detecting circuit, and outputs the digital values.

22. A photodetector in which a photosensitive region has pixels in a two-dimensional array,

wherein one pixel is configured by disposing a plurality of photosensitive portions adjacent to each other in one plane, each of the plurality of photosensitive portions outputting an electric current corresponding to an intensity of light incident on each of the photosensitive portions;

the photosensitive portions on one side, amongst the plurality of photosensitive portions configuring each of the pixels, are electrically connected to each other by one wiring across the plurality of pixels arrayed in a first direction in the two-dimensional array; and

the photosensitive portions on the other side, amongst the plurality of photosensitive portions configuring each of the pixels, are electrically connected to each other by one wiring across the plurality of pixels arrayed in a second direction in the two-dimensional array,

wherein each of the photosensitive portions includes a semiconductor substrate portion made of a first conductive type semiconductor, and a second conductive type semiconductor region formed in the semiconductor substrate portion, and

the second conductive type semiconductor region is in a shape of an approximate triangle when viewed from a light incident direction, the approximate triangle being formed so that one side thereof is adjacent to one side of another approximate triangle in the pixel.

23. A photodetector in which a photosensitive region has pixels in a two-dimensional array,

wherein one pixel is configured by disposing a plurality of photosensitive portions adjacent to each other in one plane, each of the plurality of photosensitive portions outputting an electric current corresponding to an intensity of light incident on each of the photosensitive portions;

the photosensitive portions on one side, amongst the plurality of photosensitive portions configuring each of the pixels, are electrically connected to each other by one wiring across the plurality of pixels arrayed in a first direction in the two-dimensional array; and

the photosensitive portions on the other side, amongst the plurality of photosensitive portions configuring each of the pixels, are electrically connected to each other by one wiring across the plurality of pixels arrayed in a second direction in the two-dimensional array,

the photodetector further comprising;

first integrating circuits which are provided corresponding to groups of the photosensitive portions on one side which are electrically connected across the plurality of pixels arrayed in the first direction, convert electric currents from the corresponding groups of the photosensitive portions on one side into voltages, and then output voltages;

first CDS circuits which are provided corresponding to the first integrating circuits, and output voltages with values defined according to variations in the voltages outputted from the corresponding first integrating circuits;

first sample-and-hold circuits which are provided corresponding to the first CDS circuits, and hold and output the voltages from the corresponding first CDS circuits;

a first maximum value detecting circuit which detects maximum values of the voltages from each of the first sample-and-hold circuits;

a first A/D conversion circuit which sequentially inputs the voltages from each of the first sample-and-hold circuits, converts the voltages into digital values based on the maximum values detected by the first maximum value detecting circuit, and outputs the digital values;

second integrating circuits which are provided corresponding to groups of the photosensitive portions on the other side which are electrically connected across the plurality of pixels arrayed in the second direction, convert electric currents from the corresponding groups of the photosensitive portions on the other side into voltages, and then output voltages;

second CDS circuits which are provided corresponding to the second integrating circuits, and output voltages with values defined according to variations in the voltages outputted from the corresponding second integrating circuits;

second sample-and-hold circuits which are provided corresponding to the second CDS circuits, and hold and output the voltages from the corresponding second CDS circuits;

a second maximum value detecting circuit which detects maximum values of the voltages from each of the second sample-and-hold circuits; and

a second A/D conversion circuit which sequentially inputs the voltages from each of the second sample-and-hold circuits, converts the voltages into digital values based on the maximum values detected by the second maximum value detecting circuit, and outputs the digital values.

24. A photodetector having photosensitive region,

wherein the photosensitive region includes a plurality of first photosensitive portions electrically connected to each other by one wiring across a first direction and a plurality of second photosensitive portions electrically connected to each other by one wiring across a second direction which intersects the first direction, and

the plurality of first photosensitive portions and the plurality of second photosensitive portions are arrayed to be two-dimensionally mixed within one plane,

the photodetector further comprising:

first integrating circuits which are provided corresponding to groups of the first photosensitive portions which are electrically connected to each other across the first direction, convert electric currents from the corresponding groups of the first photosensitive portions into voltages, and then output voltages;

first CDS circuits which are provided corresponding to the first integrating circuits, and output voltages with values defined according to variations in the voltages outputted from the corresponding first integrating circuits;

first sample-and-hold circuits which are provided corresponding to the first CDS circuits, and hold and output the voltages from the corresponding first CDS circuits;

a first maximum value detecting circuit which detects maximum values of the voltages from each of the first sample-and-hold circuits;

a first A/D conversion circuit which sequentially inputs the voltages from each of the first sample-and-hold circuits, converts the voltages into digital values based on the maximum values detected by the first maximum value detecting circuit, and outputs the digital values;

second integrating circuits which are provided corresponding to groups of the second photosensitive portions which are electrically connected to each other across the second direction, convert electric currents from the corresponding groups of the second photosensitive portions into voltages, and then output voltages;

second CDS circuits which are provided corresponding to the second integrating circuits, and output voltages with values defined according to variations in the voltages outputted from the corresponding second integrating circuits;

second sample-and-hold circuits which are provided corresponding to the second CDS circuits, and hold and output the voltages from the corresponding second CDS circuits;

a second maximum value detecting circuit which detects maximum values of the voltages from each of the second sample-and-hold circuits; and

a second A/D conversion circuit which sequentially inputs the voltages from each of the second sample-and-hold circuits, converts the voltages into digital values based on the maximum values detected by the second maximum value detecting circuit, and outputs the digital values.

25. A range image capture device, comprising:

a pair of imaging devices arranged at a predetermined interval, each imaging device including a photodetector being provided in a two-dimensional array,

the photodetector comprising;

a photosensitive region having pixels in a two-dimensional array,

wherein one pixel is configured by disposing a plurality of photosensitive portions adjacent to each other in one plane, each of the plurality of photosensitive portions outputting an electric current corresponding to an intensity of light incident on each of the photosensitive portions;

the photosensitive portions on one side, amongst the plurality of photosensitive portions configuring each of the pixels, are electrically connected to each other by one wiring across the plurality of pixels arrayed in a first direction in the two-dimensional array; and

the photosensitive portions on the other side, amongst the plurality of photosensitive portions configuring each of the pixels, are electrically connected to each other by one wiring across the plurality of pixels arrayed in a second direction in the two-dimensional array,

wherein the photodetector, having a plurality of the photodetectors arranged in the second direction in the two-dimensional array, further includes;

a first shift register for sequentially reading electric currents in the second direction, the electric currents being from groups of the photosensitive portions on one side which are electrically connected across the plurality of pixels arrayed in the first direction; and

first integrating circuits which are provided for the photodetector having the plurality of photodetectors arranged in the second direction, and sequentially input the electric currents from each of the groups of photosensitive portions on one side, the electric currents being sequentially read by the first shift register, and convert the electric currents into voltages, and

wherein the photodetector, having a plurality of the photodetectors arranged in the first direction in the two-dimensional array, further includes;

a second shift register for sequentially sensing electric currents in the first direction, the electric currents being from groups of the photosensitive portions on the other side which are electrically connected across the plurality of pixels arrayed in the second direction; and

second integrating circuits which are provided for the photodetector having the plurality of photodetectors arranged in the first direction, and sequentially input the electric currents from each of the groups of photosensitive portions on the other side, the electric currents being sequentially read by the second shift register, and convert the electric currents into voltages;

the range image capture device further comprising;

parallax amount determining means for determining an amount of parallax per each of the photodetectors based on the voltages from the first integrating circuits and the second integrating circuits;

distance operation means for operating a distance to an object from each of the photodetectors based on the amount of parallax determined by the parallax amount determining means; and

range image generating means for generating a range image based on the distance operated by the distance operation means.

26. A range image capture device, comprising:

a pair of imaging devices arranged at a predetermined interval, each imaging device including a photodetector being provided in a two-dimensional array,

the photodetector comprising;

a photosensitive region,

wherein the photosensitive region includes a plurality of first photosensitive portions electrically connected to each other by one wiring across a first direction and a plurality of second photosensitive portions electrically connected to each other by one wiring across a second direction which intersects the first direction, and

the plurality of first photosensitive portions and the plurality of second photosensitive portions are arrayed to be two-dimensionally mixed within one plane,

wherein the photodetector, having a plurality of the photodetectors arranged in the second direction in the two-dimensional array, further includes;

a first shift register for sequentially reading electric currents in the second direction, the electric currents being from groups of the photosensitive portions on one side which are electrically connected across the plurality of pixels arrayed in the first direction; and

first integrating circuits which are provided for the photodetector having the plurality of photodetectors arranged in the second direction, and sequentially input the electric currents from each of the groups of photosensitive portions on one side, the electric currents being sequentially read by the first shift register, and convert the electric currents into voltages, and

wherein the photodetector, having a plurality of the photo detectors arranged in the first direction in the two-dimensional array, further includes;

a second shift register for sequentially sensing electric currents in the first direction, the electric currents being from groups of the photosensitive portions on the other side which are electrically connected across the plurality of pixels arrayed in the second direction; and

second integrating circuits which are provided for the photodetector having the plurality of photodetectors arranged in the first direction, and sequentially input the electric currents from each of the groups of photosensitive portions on the other side, the electric currents being sequentially read by the second shift register, and convert the electric currents into voltages;

the range image capture device further comprising;

parallax amount determining means for determining an amount of parallax per each of the photodetectors based on the voltages from the first integrating circuits and the second integrating circuits;

distance operation means for operating a distance to an object from each of the photodetectors based on the amount of parallax determined by the parallax amount determining means; and

range image generating means for generating a range image based on the distance operated by the distance operation means.