Image sensor and electronic device
10594970 ยท 2020-03-17
Assignee
Inventors
Cpc classification
H04N25/778
ELECTRICITY
G02B7/346
PHYSICS
H01L27/14641
ELECTRICITY
International classification
Abstract
The present disclosure relates to an image sensor and an electronic device that can reduce occurrence of a problem not only in a case of adding and using outputs of a plurality of PDs that share one of on-chip lenses but also in a case of using them individually. An image sensor according to a first aspect of the present disclosure includes: a light receiving element that generates charges by photoelectric conversion; an on-chip lens that is shared by a plurality of light receiving elements and condenses incident light onto the plurality of light receiving elements; and an AD convertor that converts charges generated by the light receiving element to a digital signal. Exposure timings of the plurality of light receiving elements sharing one of the on-chip lenses are the same. The present disclosure can be applied, for example, to image pickup devices having an image-plane phase-difference detection AF function.
Claims
1. An image sensor, comprising: a plurality of light receiving elements, wherein each light receiving element of the plurality of light receiving elements is configured to generate charges based on photoelectric conversion; a plurality of on-chip lenses, wherein the plurality of light receiving elements shares one on-chip lens of the plurality of on-chip lenses; a plurality of floating diffusion (FD) sharing units, wherein each light receiving element of the plurality of light receiving elements corresponds to a different FD sharing unit of the plurality of FD sharing units; and a plurality of analog-digital (AD) convertors configured to convert the charges generated by the plurality of light receiving elements to a plurality of digital signals, wherein an exposure timing of each light receiving element of the plurality of light receiving elements is same.
2. The image sensor according to claim 1, further comprising: an adder configured to: add the charges generated by each light receiving element of the plurality of light receiving elements; and supply the added charges to at least one AD convertor of the plurality of AD convertors.
3. The image sensor according to claim 1, wherein each AD convertor of the plurality of AD convertors is further configured to concurrently convert the charges generated by each light receiving element of the plurality of light receiving elements to a corresponding digital signal of the plurality of digital signals.
4. The image sensor according to claim 3, wherein the plurality of light receiving elements is in a plurality of columns, and each AD convertor of the plurality of AD convertors is associated with a corresponding column of the plurality of columns.
5. The image sensor according to claim 1, further comprising: a plurality of holding units configured to hold the charges generated by each light receiving element of the plurality of light receiving elements, wherein each light receiving element of the plurality of light receiving elements is associated with a common AD convertor of the plurality of AD convertors, and the common AD convertor is configured to concurrently convert the charges generated by each light receiving element of the plurality of light receiving elements to a corresponding digital signal of the plurality of digital signals.
6. The image sensor according to claim 5, wherein the plurality of light receiving elements is in a plurality of columns, each column of the plurality of columns has a corresponding holding unit of the plurality of holding units, and each alternate column of the plurality of columns has a corresponding AD convertor of the plurality of AD convertors.
7. The image sensor according to claim 5, wherein the plurality of light receiving elements is in a plurality of columns, each holding unit of the plurality of holding units is associated with a corresponding light receiving element of the plurality of light receiving elements, and each AD convertor of the plurality of AD convertors is associated with a corresponding column of the plurality of columns.
8. The image sensor according to claim 1, further comprising: a holding unit configured to hold the charges generated by each light receiving element of the plurality of light receiving elements, wherein each light receiving element of the plurality of light receiving elements is associated with a common AD convertor of the plurality of AD convertors, and the common AD convertor is configured to concurrently convert the charges generated by each light receiving element of the plurality of light receiving elements to a corresponding digital signal of the plurality of digital signals.
9. The image sensor according to claim 1, further comprising a plurality of holding units, wherein the plurality of light receiving elements includes a pair of light receiving elements, a holding unit of the plurality of holding units is configured to hold the charges generated by one of the pair of light receiving elements, each light receiving element of the pair of light receiving elements is associated with a common AD convertor of the plurality of AD convertors, and the common AD convertor is configured to concurrently convert the charges generated by other of the pair of light receiving elements and the charges held in the holding unit to a corresponding digital signal of the plurality of digital signals.
10. The image sensor according to claim 9, wherein the plurality of light receiving elements is in a plurality of columns, and the plurality of holding units and the plurality of AD convertors are alternately arranged for the plurality of columns.
11. The image sensor according to claim 10, wherein each holding unit of the plurality of holding units is associated with a corresponding FD sharing unit of the plurality of FD sharing units.
12. An electronic device, comprising: an image sensor that includes: a plurality of light receiving elements, wherein each light receiving element of the plurality of light receiving elements is configured to generate charges based on photoelectric conversion; a plurality of on-chip lenses, wherein a the plurality of light receiving elements shares one on-chip lens of the plurality of on-chip lenses; a plurality of floating diffusion (FD) sharing units, wherein each light receiving element of the plurality of light receiving elements corresponds to a different FD sharing unit of the plurality of FD sharing units; and a plurality of analog-digital AD convertors configured to convert the charges generated by the plurality of light receiving elements to a digital signal, wherein an exposure timing of each light receiving element of the plurality of light receiving elements is same.
Description
BRIEF DESCRIPTION OF DRAWINGS
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MODE(S) FOR CARRYING OUT THE INVENTION
(23) Hereinafter, preferred forms for practicing the present disclosure (hereinafter, called embodiments) will be described in detail with reference to the drawings.
(24) <Outline of Image Sensors to which the Present Disclosure is Applied>
(25)
(26)
(27)
(28)
(29) Meanwhile, in the above-described Cases 1 to 3, a light receiving element other than a PD may be used.
(30) <Examples of Floating Diffusion (FD) Sharing)
(31) Next,
(32)
(33)
(34) Meanwhile, the number of pixels that share an FD in the image sensor to which the present disclosure is applied is not limited to the above-described examples but design is possible with an arbitrary number.
(35) <Configuration Example in Case 1>
(36)
(37)
(38)
(39) When attention is paid to two B (BLUE) pixels (PDs) that are arranged in the first row from the top on the left side in
(40)
(41) In the image sensor 20 in
(42)
(43) In the image sensor 20 in
(44) <Configuration Example in Case 2>
(45)
(46)
(47)
(48)
(49) When attention is paid to two B (BLUE) pixels (PDs) that are arranged in the first row from the top on the left side in
(50)
(51) Charges are read out simultaneously from L and R of the pixel pair 41 if each of switches is controlled according to
(52) Meanwhile, the image sensor 40 can read out simultaneously charges from L and R of the pixel pair 41 to hold the charges in the same capacitance (capacitance 42 or 46) and output the held charges if the switch SF_1 that links the vertical signal lines V1 and V3 is turned on, that is, can add and output charges from the pixel pair 41, although illustration of the timing chart is omitted.
(53)
(54) When attention is paid to two B (BLUE) pixels (PDs) that are arranged in the first row from the top on the left side in
(55) In the image sensor 70 shown in
(56) <Configuration Example in Case 3>
(57)
(58)
(59)
(60)
(61) When attention is paid to two B (BLUE) pixels (PDs) that are arranged in the first row from the top on the left side in
(62) In the image sensor 90 shown in
(63)
(64) When attention is paid to two B (BLUE) pixels (PDs) that are arranged in the first row from the top on the left side in
(65) In the image sensor 110 shown in
(66) <Conclusion>
(67) According to the above-described image sensors 10 to 110, it is possible to make exposure times and their timings of a pixel pair that shares an on-chip lens coincide with each other and to output these outputs individually or after addition.
(68) Meanwhile, in the present embodiment, it is so configured that an on-chip lens is shared by two PDs that are arranged laterally, but the number and arrangement of PDs that share an on-chip lens are not limited to this. For example, an on-chip lens may be shared by two PDs that are arranged vertically, or an on-chip lens may be shared by two PDs that are arranged vertically, or may be shared by three or more PDs.
(69) Moreover, the present disclosure can also be applied to a case of providing an ADC for each pixel (PD).
(70) <Use Examples of Image Sensor>
(71)
(72) The above-described image sensor can be used for, for example, various cases in which light such as visible light, infrared light, ultraviolet light, or X-rays is detected as follows. Devices that take images used for viewing, such as a digital camera and a portable appliance with a camera function. Devices used for traffic, such as an in-vehicle sensor that takes images of the front and the back of a car, surroundings, the inside of the car, and the like, a monitoring camera that monitors travelling vehicles and roads, and a distance sensor that measures distances between vehicles and the like, which are used for safe driving (e.g., automatic stop), recognition of the condition of a driver, and the like. Devices used for home electrical appliances, such as a TV, a refrigerator, and an air conditioner, to takes images of a gesture of a user and perform appliance operation in accordance with the gesture. Devices used for medical care and health care, such as an endoscope and a device that performs angiography by reception of infrared light. Devices used for security, such as a monitoring camera for crime prevention and a camera for personal authentication. Devices used for beauty care, such as skin measurement equipment that takes images of the skin and a microscope that takes images of the scalp. Devices used for sports, such as an action camera and a wearable camera for sports and the like. Devices used for agriculture, such as a camera for monitoring the condition of the field and crops.
(73) An embodiment of the disclosure is not limited to the embodiments described above, and various changes and modifications may be made without departing from the scope of the disclosure.
(74) Additionally, the present technology may also be configured as below.
(75) (1)
(76) An image sensor including:
(77) a light receiving element that generates charges by photoelectric conversion;
(78) an on-chip lens that is shared by a plurality of light receiving elements and condenses incident light onto the plurality of light receiving elements; and
(79) an AD convertor that converts charges generated by the light receiving element to a digital signal,
(80) in which exposure timings of the plurality of light receiving elements sharing one of the on-chip lenses are the same.
(81) (2)
(82) The image sensor according to (1), further including:
(83) an adder that adds charges that are generated by each of the plurality of light receiving elements sharing one of the on-chip lenses and supplies the added charges to the AD convertor.
(84) (3)
(85) The image sensor according to (1) or (2),
(86) in which charges that are generated by each of the plurality of light receiving elements sharing one of the on-chip lenses are converted simultaneously to digital signals by the AD convertors that are different.
(87) (4)
(88) The image sensor according to any of (1) to (3),
(89) in which the plurality of light receiving elements sharing one of the on-chip lenses belong to different FD sharing units.
(90) (5)
(91) The image sensor according to (4),
(92) in which the AD convertor is provided for every column.
(93) (6)
(94) The image sensor according to (1) or (2), further including:
(95) a plurality of holding units that hold charges generated by each of the plurality of light receiving elements sharing one of the on-chip lenses,
(96) in which charges that are held in the plurality of holding units are converted sequentially to digital signals by the AD convertor in common.
(97) (7)
(98) The image sensor according to (6),
(99) in which the plurality of light receiving elements sharing one of the on-chip lenses belong to different FD sharing units.
(100) (8)
(101) The image sensor according to (7), in which
(102) the holding unit is provided for every column, and
(103) the AD convertor is provided for every other column.
(104) (9)
(105) The image sensor according to (6),
(106) in which the plurality of light receiving elements sharing one of the on-chip lenses belong to a same FD sharing unit.
(107) (10)
(108) The image sensor according to (9), in which
(109) the holding unit is provided for every light receiving element, and
(110) the AD convertor is provided for every column.
(111) (11)
(112) The image sensor according to (1) or (2), further including:
(113) a holding unit that holds charges generated by the plurality of light receiving elements sharing one of the on-chip lenses,
(114) in which charges generated by each of the plurality of light receiving elements sharing one of the on-chip lenses and charges held in the holding unit are converted sequentially to digital signals by the AD convertor in common.
(115) (12)
(116) The image sensor according to (1), (2), or (11), further including:
(117) a holding unit that holds charges generated by one of a light receiving element pair sharing one of the on-chip lenses,
(118) in which charges generated by one of the light receiving element pair, and charges generated by the other of the light receiving element pair and held in the holding unit are converted sequentially to digital signals by the AD convertor in common.
(119) (13)
(120) The image sensor according to (12),
(121) in which the plurality of light receiving elements sharing one of the on-chip lenses belong to different FD sharing units.
(122) (14)
(123) The image sensor according to (13), in which
(124) the holding unit is provided for every other column, and
(125) the AD convertor is provided for every other column.
(126) (15)
(127) The image sensor according to (14),
(128) in which the plurality of light receiving elements sharing one of the on-chip lenses belong to the same FD sharing unit.
(129) (16)
(130) The image sensor according to (15), in which
(131) the holding unit is provided for every FD sharing unit, and
(132) the AD convertor is provided for every column.
(133) (17)
(134) An electronic device on which an image sensor is mounted,
(135) the image sensor including a light receiving element that generates charges by photoelectric conversion, an on-chip lens that is shared by a plurality of light receiving elements and condenses incident light onto the plurality of light receiving elements, and an AD convertor that converts charges generated by the light receiving element to a digital signal, in which exposure timings of the plurality of light receiving elements sharing one of the on-chip lenses are the same.
REFERENCE SIGNS LIST
(136) 10 image sensor 20 image sensor 21 pixel pair 22 FD 23 ADC 24 FD 25 ADC 30 image sensor 40 image sensor 41 pixel pair 42 FD 43 capacitance 44 ADC 45 FD 46 capacitance 50 image sensor 60 image sensor 70 image sensor 80 image sensor 90 image sensor 91 pixel pair 92 FD 93 capacitance 94 ADC 95 FD 100 image sensor 110 image sensor 111 pixel pair 112 capacitance 113 FD 114 ADC 115 ADC 120 image sensor