IMAGE SENSOR INCLUDING A PIXEL HAVING PHOTOELECTRIC CONVERSION ELEMENTS AND IMAGE PROCESSING DEVICE HAVING THE IMAGE SENSOR
20170338258 ยท 2017-11-23
Assignee
Inventors
- Tae Chan KIM (Yongin-si, KR)
- Dong Ki Min (Seoul, KR)
- Kwang Hyun Lee (Seongnam-si, KR)
- Yo Hwan Noh (Yongin-si, KR)
- Se Hwan Yun (Hwaseong-si, KR)
- Dae Kwan Kim (Suwon-si, KR)
- Young Jin Kim (Seoul, KR)
- Wang Hyun Kim (Namyangju-si, KR)
- Hyuk Soon Choi (Hwaseong-si, KR)
Cpc classification
G02B3/0056
PHYSICS
H04N25/778
ELECTRICITY
H04N25/533
ELECTRICITY
H10F39/803
ELECTRICITY
H10F39/813
ELECTRICITY
H04N25/75
ELECTRICITY
International classification
Abstract
An image sensor according to an example embodiment concepts includes a pixel array including pixels, and each of the pixels includes photoelectric conversion elements. The photoelectric conversion elements independently operating to detect a phase difference. The image sensor further includes a control circuit configured to independently control exposure times of each of the photoelectric conversion elements included in each of the pixels.
Claims
1-21. (canceled)
22. An image sensor comprising: a pixel array including a plurality of pixels arranged in a plurality of rows and a plurality of columns, the plurality of pixels including a plurality of photoelectric conversion elements, the plurality of rows including a first row and a second row that is adjacent to the first row, the plurality of photoelectric conversion elements including a plurality of first photoelectric conversion elements included in pixels arranged in the first row and a plurality of second photoelectric conversion elements included in pixels arranged in the second row; a control circuit configured to control exposure times of the plurality of photoelectric conversion elements; and a plurality of transfer lines coupled to the plurality of photoelectric conversion elements, and including a first transfer line, a second transfer line, a third transfer line and a fourth transfer line, wherein the plurality of first photoelectric conversion elements are coupled to the first transfer line and the second transfer line, the plurality of second photoelectric conversion elements are coupled to the third transfer line and the fourth transfer line, a binning operation is performed between a first element and a second element, the first element being one of the plurality of first photoelectric conversion elements, the second element being one of the plurality of second photoelectric conversion elements, and the first element and the second element capture light having the same color.
23. The image sensor of claim 22, wherein each of the plurality of pixels include a color filter.
24. The image sensor of claim 22, wherein the control circuit controls the exposure times based on a binning condition.
25. The image sensor of claim 22, wherein the control circuit outputs a plurality of control signals for controlling the exposure times.
26. The image sensor of claim 22, wherein the exposure times include a first exposure time and a second exposure time that is different from the first exposure time, and the control circuit outputs a first control signal for controlling the first exposure time and a second control signal for controlling the second exposure time.
27. The image sensor of claim 22, wherein each of the plurality of pixels includes at least one photoelectric conversion element that generates a first exposure image signal and at least one photoelectric conversion element that generates a second exposure image signal different from the first exposure image signal.
28. The image sensor of claim 27, wherein the control circuit controls both the at least one photoelectric conversion element that generates the first exposure image signal and the at least one photoelectric conversion element that generates the second exposure image signal.
29. The image sensor of claim 27, wherein the first transfer line is coupled to the at least one photoelectric conversion element that generates the first exposure image signal, and the second transfer line is coupled to the at least one photoelectric conversion element that generates the second exposure image signal.
30. An image sensor comprising: a pixel array including a plurality of pixels arranged in a plurality of rows and a plurality of columns, the plurality of pixels including a plurality of photoelectric conversion elements, the plurality of rows including a first row, a second row adjacent to the first row and a third row adjacent to the second row, the plurality of photoelectric conversion elements including a plurality of first photoelectric conversion elements included in pixels arranged in the first row, a plurality of second photoelectric conversion elements included in pixels arranged in the second row and a plurality of third photoelectric conversion elements included in pixels arranged in the third row; a control circuit configured to control exposure times of the plurality of photoelectric conversion elements; and a plurality of transfer lines coupled to the plurality of photoelectric conversion elements, and including a first transfer line, a second transfer line and a third transfer line, wherein the plurality of first photoelectric conversion elements are coupled to the first transfer line, the plurality of second photoelectric conversion elements are coupled to the second transfer line, the plurality of third photoelectric conversion elements are coupled to the third transfer line, a binning operation is performed between at least two of a first element, a second element and a third element, the first element being one of the plurality of first photoelectric conversion elements, the second element being one of the plurality of second photoelectric conversion elements, the third element being one of the plurality of second photoelectric conversion elements, and the first element, the second element and the third element capture light having the same color.
31. The image sensor of claim 30, wherein each of the plurality of pixels includes at least one photoelectric conversion element that generates a first exposure image signal and at least one photoelectric conversion element that generates a second exposure image signal different from the first exposure image signal.
32. The image sensor of claim 31, wherein the control circuit controls both the at least one photoelectric conversion element that generates the first exposure image signal and the at least one photoelectric conversion element that generates the second exposure image signal.
33. The image sensor of claim 31, wherein the plurality of transfer lines include a fourth transfer line coupled to the plurality of first photoelectric conversion elements, a fifth transfer line coupled to the plurality of second photoelectric conversion elements, and a sixth transfer line coupled to the plurality of third photoelectric conversion elements.
34. The image sensor of claim 33, wherein the first transfer line is coupled to the at least one photoelectric conversion element that generates the first exposure image signal, and the fourth transfer line is coupled to the at least one photoelectric conversion element that generates the second exposure image signal.
35. An image sensor comprising: a pixel array including a plurality of pixels arranged in a plurality of rows and a plurality of columns, the plurality of pixels including a plurality of photoelectric conversion elements, the plurality of rows including a first row and a second row that is adjacent to the first row, the plurality of photoelectric conversion elements including a plurality of first photoelectric conversion elements included in pixels arranged in the first row and a plurality of second photoelectric conversion elements included in pixels arranged in the second row; a control circuit configured to control exposure times of the plurality of photoelectric conversion elements; and a plurality of transfer lines coupled to the plurality of photoelectric conversion elements, and including a first transfer line and a second transfer line, wherein the plurality of first photoelectric conversion elements are coupled to the first transfer line, the plurality of second photoelectric conversion elements are coupled to the second transfer line, a binning operation is performed between a first element and a second element that are included in the plurality of first photoelectric conversion elements or the plurality of second photoelectric conversion elements, and with respect to the first element, the second element is one of the closest photoelectric conversion elements that captures light having the same color as the first element.
36. The image sensor of claim 35, wherein the first element and the second element are vertically adjacently arranged.
37. The image sensor of claim 35, wherein the first element and the second element are horizontally adjacently arranged.
38. The image sensor of claim 35, wherein the first element and the second element are arranged in the same pixel.
39. The image sensor of claim 35, wherein the first element is arranged in a different pixel from a pixel where the second element is arranged.
40. The image sensor of claim 35, wherein each of the plurality of pixels includes at least one photoelectric conversion element that generates a first exposure image signal and at least one photoelectric conversion element that generates a second exposure image signal different from the first exposure image signal, and each of the first element and the second element is a photoelectric conversion element that generates the first exposure image signal.
41. The image sensor of claim 35, wherein the plurality of transfer lines include a third transfer line coupled to the plurality of first photoelectric conversion elements, and a fourth transfer line coupled to the plurality of second photoelectric conversion elements, the first transfer line is coupled to at least one photoelectric conversion element that generates a first exposure image signal, and the third transfer line is coupled to at least one photoelectric conversion element that generates a second exposure image signal.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] These and/or other aspects and advantages of the present inventive concepts will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
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DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0054] The present inventive concepts now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. The inventive concepts may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like numbers refer to like elements throughout.
[0055] It will be understood that when an element is referred to as being connected or coupled to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being directly connected or directly coupled to another element, there are no intervening elements present. As used herein, the term and/or includes any and all combinations of one or more of the associated listed items and may be abbreviated as /.
[0056] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first signal could be termed a second signal, and, similarly, a second signal could be termed a first signal without departing from the teachings of the disclosure.
[0057] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms comprises and/or comprising, or includes and/or including when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.
[0058] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present application, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0059]
[0060] The pixel array 100 may be included in a portable electronic device. The portable electronic device may be used in a laptop computer, a cellular phone (or mobile phone), a smart phone, a tablet PC, a digital camera, a camcorder, a mobile internet device (MID), wearable computer, an internet of things (IoT) device, an internet of everything (IoE) device, and the like.
[0061] Each of the photodiodes included in the pixel array 100 may be any photo-electric conversion element and may be replaced with a phototransistor, a photogate, or a pinned-photodiode, as an example of a photo-electric conversion element.
[0062] Each of the multiple photodiodes included in each pixel may independently capture light or an image.
[0063] In
[0064]
[0065] In
[0066] Each of the pixels G and R disposed in respective rows Row1 and Row3 includes two photodiodes L and S.
[0067] Each of the pixels B and G disposed in respective rows Row2 and Row4 includes two photodiodes L and S.
[0068] Exposure time or integration time of each of the photodiodes L and S included in each of the pixels R, G, and B may be controlled to be different from each other in an independent manner by a row driver.
[0069] For convenience of description in
[0070]
[0071] Positions of two photodiodes L and S included in rows Row3 and Row4 of
[0072] As exemplarily shown in
[0073] For example, the gate of a transfer transistor, which is connected to each photodiode L of each of the pixels R, G, and B disposed in each of the rows Row1 to Row4, is connected to the first corresponding transfer line (or the first metal line; LINE1); and the gate of a transfer transistor, which is connected to each photodiode S of each of the pixels R, G, and B, is connected to the second corresponding transfer transistor (or the second metal line; LINE2).
[0074]
[0075] According to an example embodiment, exposure time or integration time of each of the photodiodes L1, L2, S1, and S2 included in each of the pixels R, G, and B may be controlled to be different from each other in an independent manner by a row driver.
[0076] According to another example embodiment, exposure time or integration time of each of the photodiodes L1 and L2 included in each of the pixels R, G, and B may be controlled to be the same as each other by a row driver, and exposure time or integration time of each of photodiodes S1 and S2 included in each of the pixels R, G, and B may be controlled to be the same as each other by the row driver.
[0077] The exposure time or the integration time of each of the photodiodes L1 and L2 may be set to be longer than the exposure time or the integration time of each of the photodiodes S1 and S2.
[0078] Physical characteristics of each of the photodiodes L1 and L2 may be the same as or different from each other. Moreover, physical characteristics of each of the photodiodes S1 and S2 may be the same as or different from each other.
[0079] L1 means a first photodiode, S1 means a second photodiode, L2 means a third photodiode, and S2 means a fourth photodiode.
[0080] For example, each of L1 and L2 may be a photodiode which can generate a long-exposure image signal, and each of S1 and S2 may be a photodiode which can generate a short-exposure image signal.
[0081] Each of the pixels G and R disposed in a row Row1 includes four photodiodes L1, L2, S1, and S2.
[0082] Each of the pixels B and G disposed in a row Row2 includes four photodiodes L1, L2, S1, and S2.
[0083] Each of the pixels R, G, and B includes two photodiodes L1 and L2 which can generate long-exposure image signals, and includes two photodiodes S1 and S2 which can generate short-exposure image signals. Accordingly to one or more embodiments, a position of each of the photodiodes L1, L2, S1, and S2 may be variously changed according to a design specification.
[0084] For example, a gate of each transfer transistor connected to each of the photodiodes L1 and L2 of each of the pixels R, G, and B disposed in each of the rows Row1 and Row2 is connected to the first corresponding transfer line (or the first metal line; LINE1), and a gate of each transfer transistor connected to each of the photodiodes S1 and S2 of each of the pixels R, G, and B is connected to the second corresponding transfer line (or the second metal line; LINE2) as shown in
[0085]
[0086] That is, each of the pixels R, G, and B includes three photodiodes L1, L2, and L3 which can generate long-exposure image signals, and includes one photodiode S1 which can generate short-exposure image signals. Accordingly to one or more embodiments, a position of each of the photodiodes L1, L2, L3, and S1 may be variously changed according to the design specification.
[0087] According to an example embodiment, exposure time or integration time of each of the photodiodes L1, L2, L3, and S1 included in each of the pixels R, G, and B may be controlled to be different from each other in an independent manner by the row driver.
[0088] According to another example embodiment, exposure time or integration time of each of the photodiodes L1, L2, and L3 included in each of the pixels R, G, and B may be controlled to be the same as each other by the row driver. The exposure time or integration time of each of the photodiodes L1, L2, and L3 may be set to be longer than the exposure time or integration time of the photodiode S1.
[0089] Physical characteristics of each of the photodiodes L1, L2, and L3 may be embodied to be the same as or different from each other.
[0090] L1 represents a first photodiode, L2 represents a second photodiode, L3 represents a third photodiode, and S1 represents a fourth photodiode.
[0091] For example, each of the photo diodes L1, L2, and L3 may be a photodiode which can generate long-exposure image signal, and the photo diode S1 may be a photodiode which can generate short-exposure image signal.
[0092] Each of the pixels G and R disposed in a row Row1 includes four photodiodes L1, L2, L3, and S1.
[0093] Each of the pixels B and G disposed in a row Row2 includes four photodiodes L1, L2, L3, and S1.
[0094] For example, a gate of each transfer transistor connected to each of the photodiodes L1, L2, and L3 of each of the pixels R, G, and B disposed in each of the rows Row1 and Row2 is connected to the first corresponding transfer line (or the first metal line; LINE1), and a gate of each transfer transistor connected to the photodiodes S1 of each of the pixels R, G, and B is connected to the second corresponding transfer line (or the second metal line; LINE2) as shown in
[0095]
[0096] That is, each of the pixels R, G, and B includes one photodiode L1 which can generate long-exposure image signals, and includes three photodiodes S1, S2, and S3 which can generate short-exposure image signals, respectively. According to one or more embodiments, a position of each of the photodiodes S1, S2, S3, and L1 may be variously changed according to the design specification.
[0097] According to an example embodiment, exposure time or integration time of each of the photodiodes S1, S2, S3, and L1 included in each of the pixels R, G, and B may be controlled to be different from each other in an independent manner by the row driver.
[0098] According to another example embodiment, exposure time or integration time of each of the photodiodes S1, S2, and S3 included in each of the pixels R, G, and B may be controlled to be the same as each other by the row driver.
[0099] Physical characteristics of each of the photodiodes S1, S2, and S3 may be embodied to be the same as or different from each other.
[0100] S1 means a first photodiode, S2 means a second photodiode, S3 means a third photodiode, and L1 means a fourth photodiode.
[0101] For example, the photo diode L1 may be a photodiode which can generate long-exposure image signal, each of photo diodes S1, S2, and S3 may be a photodiode which can generate short-exposure image signal.
[0102] Each of the pixels G and R disposed in a row Row1 includes four photodiodes S1, S2, S3, and L1.
[0103] Each of the pixels B and G disposed in a row Row2 includes four photodiodes S1, S2, S3, and L1.
[0104] For example, a gate of each transfer transistor connected to each of the photodiodes S1, S2, and S3 of each of the pixels R; G, and B disposed in each of the rows Row1 and Row2 is connected to the first corresponding transfer line (or the first metal line; LINE1), and a gate of a transfer transistor connected to the photodiode L1 of each of the pixels R, G, and B is connected to the second corresponding transfer line (or the second metal line; L1NE2) as shown in
[0105]
[0106] A photodiode PD1 or PD1 may be one of a photodiode which can generate a long-exposure image signal and a photodiode which can generate a short-exposure image signal, and a photodiode PD2 or PD2 may be the other of the photodiode which can generate the long-exposure image signal and the photodiode which can generate the short-exposure image signal.
[0107] Two photodiodes PD1 and PD2, and PD1 and PD2 may be formed in a silicon substrate, and deep trench isolation (DTI) may be formed between two photodiodes PD1 and PD2, and PD1 and PD2. For example, in-pixel DTI may be formed between the two photodiodes PD1 and PD2, and PD1 and PD2 and inter-pixel DTI may be formed between pixels.
[0108] A metal wiring, a multi-layer wiring, or wiring layers may be formed in a circuit region formed between the two photodiodes PD1 and PD2, and PD1 and PD2 and a color filter. A lens buffer or a planarization layer may be formed between a microlens and the color filter.
[0109]
[0110] Referring to
[0111] Referring to
[0112] Referring to
[0113] Four photodiodes PD1 to PD4 are formed in a silicon substrate, and a corresponding DTI, e.g., an in-pixel DTI, may be formed between two photodiodes PD1 and PD2, PD2 and PD3, and PD3 and PD4. An inter-pixel DTI may be formed between pixels.
[0114] A metal wiring, a multi-layer wiring, or wiring layers may be formed in a circuit region formed between the four photodiodes PD1 to PD4 and a color filter. A lens buffer or a planarization layer may be formed between a microlens and a color filter.
[0115]
[0116] Each of control signals TG1, TG2, RST, and SEL, which can control each of transistors TX1, TX2, RX, and SX, may be output from the row driver. An output signal of a selection transistor SX is supplied to a column line.
[0117] For convenience of description in
[0118]
[0119] Each of the control signal TG1 to TG4, RST, and SEL which can control each of the transistors TX1 to TX2, RX, and SX may be output from the row driver. An output signal of the selection transistor SX is supplied to a column line.
[0120] For convenience of description in
[0121]
[0122] A structure of each PAF pixel P included in the pixel array is substantially the same as a structure of a pixel described referring to
[0123] An output signal of each PAF pixel P arranged in odd numbered rows Row1, Row3, . . . , is transferred to a bottom analog-digital converter. Digital signals output from the bottom analog-digital converter may be stored in a corresponding memory or buffer.
[0124] An output signal of each PAF pixel P arranged in even numbered rows Row2, Row4, . . . , is transferred to a top analog-digital converter. Digital signals output from the top analog-digital converter may be stored in a corresponding memory or buffer.
[0125] As shown in
[0126]
[0127] An output signal of each PAF pixel P arranged in the odd numbered rows Row1, Row3, . . . , is transferred to a first analog-digital converter. Digital signals output from the first analog-digital converter may be stored in a corresponding memory or buffer. The memory or buffer may output image data.
[0128] An output signal of each PAF pixel P arranged in the even numbered rows Row2, Row4, . . . , is transferred to a second analog-digital converter. Digital signals output from the second analog-digital converter may be stored in a corresponding memory or buffer. The memory or buffer may output image data.
[0129] As shown in
[0130]
[0131] Referring to
[0132] The CMOS image sensor 505 may generate image data IDATA of an object 501 incident through the optical lens 503. The image data IDATA are data corresponding to pixel signals output from the plurality of photodiodes P.
[0133] The CMOS image sensor 505 includes the pixel array 100, a row driver 520, a readout circuit 525, a timing generator 530, a control register block 550, a reference signal generator 560, and a buffer 570.
[0134] The pixel array 100 includes a plurality of pixels P. The pixel P of the CMOS image sensor 505 may be manufactured using a CMOS manufacture process. As described referring to
[0135] The pixel array 100 includes pixels P arranged in a matrix shape. The pixels P transfer pixel signals to column lines.
[0136] The row driver 520 drives control signals to the pixel array 100 for controlling an operation of each of the pixels P according to a control of the timing generator 530.
[0137] The row driver 520 may function as a control signal generator which can generates control signals. For example, the control signals may include the control signals RST, TG1, TG2, and SEL shown in
[0138] The timing generator 530 controls an operation of the row driver 520, the readout circuit 525, and the reference signal generator 560 according to a control of the control register block 550.
[0139] The readout circuit 525 includes the analog-digital converter 526 on a column basis and a memory 527 on a column basis. According to an example embodiment, the analog-digital converter 526 may perform a function of correlated double sampling (CDS).
[0140] The read out circuit 525 outputs a digital image signal corresponding to a pixel signal output from each pixel P.
[0141] The control register block 550 controls an operation of the timing generator 530, the reference signal generator 560, and the buffer 570 according to a control of the DSP 600.
[0142] The buffer 570 transfers image data IDATA corresponding to a plurality of digital image signals output from the readout circuit 525 to the DSP 600.
[0143] The image data IDATA include first image data corresponding to long-exposure image signals and second image data corresponding to short-exposure image signals.
[0144] The DSP 600 includes an image signal processor (ISP) 610, a sensor controller 620, and an interface 630.
[0145] The ISP 610 controls the sensor controller 620 which controls the control register block 550, and the interface 630.
[0146] According to an example embodiment, the CMOS image sensor 505 and the DSP 600 may be embodied in one package, e.g., a multi-chip package (MCP).
[0147] The CMOS image sensor 505 and the ISP 610 are separated from each other in
[0148] The ISP 610 processes the image data IDATA transferred from the buffer 570, and transfers processed image data to the interface 630. For example, the ISP 610 may interpolate image data IDATA corresponding to pixel signals output from the pixels P, and generate interpolated image data.
[0149] The sensor controller 620 may generate various control signals for controlling the control register block 550 according to a control of the ISP 610.
[0150] The interface 630 may transfer the image data processed by the ISP 610, e.g., the interpolated image data, to the display 640.
[0151] The display 640 may display the interpolated image data output from the interface 630. The display 640 may be embodied in a thin film transistor-liquid crystal display (TFT-LCD), a light emitting diode (LED) display, an organic LED (OLED) display, an active-matrix OLED (AMOLED) display, or a flexible display.
[0152]
[0153] Referring to
[0154] A method of operating the reconstruction circuit 200 will be described referring to
[0155] First of all, referring to
[0156] In order to perform a long exposure and a short exposure, the long-exposure image signal and the short-exposure image signal are acquired depending on the number of rows in one field period. In order to combine the long-exposure image signal and the short-exposure image signal, captured image data are generated depending on the number of rows in one field.
[0157] A combination of the long-exposure image signal and the short-exposure image signal may be performed by the reconstruction circuit 200 of
[0158] According to an example embodiment, input image data INPUT may include long-exposure image signals corresponding to the first image data, and short-exposure image signals corresponding to the second image data.
[0159] In the combining process by the reconstruction circuit 200, a combined signal or combined image may be generated by switching signals or images at a switching point indicated by a luminance threshold expressed by a dotted line. Here, the switching point means the point of time when the long-exposure image signal is saturated.
[0160] For example, a corresponding long-exposure image signal is applied to a pixel signal having a lower luminance level than a luminance level of the switching point, and a corresponding short-exposure image signal is applied to a pixel signal having a higher luminance level than the luminance level of the switching point.
[0161] Level matching between two images is performed by multiplying the short-exposure image signal by an exposure ratio or gain. For example, the exposure ratio or gain may be determined according to a ratio between the long-exposure image signal and the short-exposure image signal.
[0162] When the exposure ratio between the long-exposure image signal and the short-exposure image signal is K:1, exposure of the short-exposure image signal is 1/K of exposure of the long-exposure image signal. A luminance level of the long-exposure image signal is K times larger than a luminance level of the short-exposure image signal. Accordingly, two levels may be matched by multiplying the short-exposure image signal by a gain K.
[0163] In this manner, the short-exposure image signal is multiplied K times. As a result, a combined image having characteristics of the long-exposure signal and characteristics of a combined signal is generated.
[0164] That is, the reconstruction circuit 200 combines the input image data INPUT as described with reference to
[0165] The reconstruction circuit 200 multiplies the short exposure image by the exposure ratio, and then generates a linear image OUTPUT1 by linearly combining an image generated as a result of the multiplication and the long exposure image. For example, when the first image data corresponding to the long-exposure image signals are M-bits (for example, 14-bits), and the second image data corresponding to the short-exposure image signals are M-bits (for example, 14-bits), the first image data and the second image data are overlapped with each other in a certain section, and an overlapped combined image OUTPUT1 becomes smaller than 2*M bits. For example, the overlapped combined image OUTPUT1 may be 14-bits. Here, each bit number means a bit number of image data corresponding to each pixel signal output from each pixel.
[0166] The dynamic range compression circuit 220 lowers the bit number (e.g., 14-bits) of the overlapped combined image OUTPUT1 to a bit (e.g., 10-bits) for a display or an output standard, and outputs an image OUTPUT2 with a lowered bit number. For example, the dynamic range compression circuit 220 reduces the bit number of the combined image OUTPUT1 using a curve such as the well-known gamma connection (e.g., embodied in a local method or a global method), and outputs an output image OUTPUT2 with a reduced bit. For example, the dynamic range compression circuit 220 may perform a function of compressing a dynamic range of the combined image OUTPUT1.
[0167]
[0168]
[0169] An output signal of the multi-diode PAF sensor 300 may be a phase difference signal, that is, a signal output from a plurality of photoelectric conversion elements (e.g., photodiodes) included in a pixel.
[0170] A color data processing circuit 310 may perform processing for improving image data using signals LDATA and SDATA output from L and S photoelectric conversion elements, respectively. The processing may include pre-processing. The pre-processing may correct a problem occurring in a manufacture process of a CMOS image sensor before image processing is performed on a main color, e.g., RGB data. The correction may include lens shading correction and/or bad pixel correction, and the like.
[0171] The processing may include main color image processing. The main color image processing may include interpolation, noise reduction, edge enhancement, color correction, and/or gamma processing.
[0172] The color data processing circuit 310 may perform at least one of the pre-processing and the main color image processing.
[0173] The PAF data processing circuit 320 performs processing for improving depth data on a PAF pixel basis. The PAF data processing circuit 320 may be phase difference auto-focus data processing, and may perform a function of converting disparity data or depth data using the signals LDATA and SDATA output from photodiodes included in each pixel. For example, the disparity data may be data for an image at one point acquired through multi-diodes. The PAF data processing circuit 320 may perform a series of processing, e.g., noise reduction, so as to obtain the disparity data or the depth data. Each of the circuits 310 and 320 may be embodied in a pipeline structure.
[0174] Color data processed by the color data processing circuit 310 and depth data processed by the PAF data processing circuit 320 may be output in synchronization with each other or sequentially in a row according to example embodiments. According to an example embodiment, when the color data and the depth data are synchronized with each other, the color data and the depth data may be output in synchronization with each other. According to another example embodiment, the depth data may be output after the color data are output, or the color data may be output after the depth data are output. According to still another example embodiment, the color data and the depth data may be alternately output. According to still another example embodiment, a method of mixing and outputting the color data and the depth data may be used.
[0175] According to some example embodiments, when the multi-diode PAF sensor 300 is embodied in a first chip, the color data processing circuit 310 and the PAF data processing circuit 320 may be embodied in a second chip. For example, the color data processing circuit 310 and the PAF data processing circuit 320 may be embodied in an ISP, an application processor, or a system on chip (SoC). A circuit shown in
[0176]
[0177] Referring to
[0178] Each of the pixels R, G, and B described in the present specification means a PAF pixel which can perform a phase detection auto-focus operation or a phase difference auto-focus operation. As shown in
[0179] A first control signal TA1 may control a transfer gate TXa1 connected to the photoelectric conversion element GrPD1, a second control signal TA2 may control a transfer gate TXa2 connected to the photoelectric conversion element GrPD2, a third control signal TA3 may control a transfer gate connected to the photoelectric conversion element RPD1, a fourth control signal TA4 may control a transfer gate connected to the photoelectric conversion element RPD2. The control signals TA1 to TA4 output from the exposure time control circuit, e.g., the row driver 520 of
[0180] A fifth control signal TB1 may control a transfer gate TXb1 connected to the photoelectric conversion element BPD1, a sixth control signal TB2 may control a transfer gate TXb2 connected to the photoelectric conversion element BPD2, a seventh control signal TB3 may control a transfer gate connected to the photoelectric conversion element GrPD1, and an eighth control signal TB4 may control a transfer gate connected to the photoelectric conversion element GrPD2. The control signals TB1 to TB4 output from the exposure time control circuit, e.g., the row driver 520 of
[0181] Charge accumulation and charge transfer by each of a plurality of photoelectric conversion elements included in each pixel may be controlled according to a corresponding control signal supplied to a gate of a corresponding transfer transistor.
[0182] According to another example embodiment, the first control signal TA1 may be supplied to a transfer gate connected to the photoelectric conversion element GrPD2 and the second control signal TA2 may be supplied to a transfer gate connected to the photoelectric conversion element GrPD1. Moreover, the design of a pixel array can be modified so that the third control signal TA3 may be supplied to a transfer gate connected to the photoelectric conversion element RPD2 and the fourth control signal TA4 may be supplied to a transfer gate connected to the photoelectric conversion element RPD1. For example, this embodiment may apply to the second column of 2 pixels shown in
[0183]
[0184]
[0185] Referring to
[0186] In a readout section READ, a floating diffusion region FD of a pixel disposed in a row corresponding to an address ADD3 different from the address ADD1 is reset. Then, the second control signal TA2 is supplied to a gate of the transfer transistor TXa2 connected to the second photoelectric conversion element GrPD2 of the pixel A disposed in a first row. Accordingly, charges accumulated in the second photoelectric conversion element GrPD2 are transferred to a floating diffusion region FD through the transfer gate TXa2, a source follower SF operates in response to the charges transferred to the floating diffusion region FD, and a signal output from the source follower SF is transferred to a column line through a selection transistor SX.
[0187]
[0188] Each of the control signals TA1, TA3, TB1, and TB3 supplied to a gate of each transfer transistor connected to each of the photoelectric conversion elements GrPD1, RPD1, BPD1, and GbPD1 corresponds to a relatively long-exposure time. However, each of the control signals TA2, TA4, TB2, and TB4 supplied to a gate of each transfer transistor connected to each of the photoelectric conversion elements GrPD2, RPD2, BPD2, and GbPD2 corresponds to a relatively short-exposure time.
[0189]
[0190] Each of the control signals TA1, TA3, TB1, and TB3 supplied to a gate of each transfer transistor connected to each of the photoelectric conversion elements GrPD1, RPD1, BPD2, and GbPD2 corresponds to a relatively long-exposure time. However, each of the control signals TA2, TA4, TB2, and TB4 supplied to a gate of each transfer transistor connected to each of the photoelectric conversion elements GrPD2, RPD2, BPD1, and GbPD1 corresponds to a relatively short-exposure time.
[0191] Since pixel signals corresponding to charges output from photoelectric conversion elements having the same exposure time are added, the row driver 520 controls each of the control signals TA1 to TA4, and TB1 to TB4 so as to perform a binning. Accordingly, the row driver 520 controls each of the control signals TA1 to TA4, and TB1 to TB4 related to exposure time according to an operation condition such as performance of PAF and/or binning.
[0192] As described referring to
[0193] Here, L and S are relative to each other, and when a control signal corresponding to a relatively short-exposure time is supplied to a gate of a transfer transistor connected to S, the S may generate charges corresponding to a relatively short-exposure image signal. In addition, when a control signal corresponding to a relatively long-exposure time is supplied to a gate of a transfer transistor connected to L, the L may generate charges corresponding to a relatively long-exposure image signal.
[0194] As described referring to
[0195]
[0196] When control signals output from the row driver 520 are supplied to gates of transfer transistors connected to photoelectric conversion elements disposed in different positions at the time point (1), pixels including the photoelectric conversion elements may output pixel signals to comparators CP1 to CP4 in parallel through corresponding column lines COL1 to COL4.
[0197] Each of the comparators CP1 to CP4 embodied in a readout circuit 525A according to an example embodiment of the readout circuit 525 of
[0198] For example, long-exposure green image signals may be output from green pixels at the same time or in parallel at the time point (1). Short-exposure green image signals may be output from green pixels at the same time or in parallel at the time point (2). Long-exposure red image signals from red pixels and long-exposure blue image signals from blue pixels may be output the same time or in parallel at the time point (3). Short-exposure red image signals from red pixels and short-exposure blue image signals from blue pixels may be output at the same time or in parallel at the time point (4).
[0199]
[0200] Referring to
[0201]
[0202]
[0203] The pixel array 100 includes a plurality of pixels. Each of the plurality of pixels may be a pixel described referring to
[0204] The exposure time control circuit 1610 may independently control exposure time of each of photoelectric conversion elements for each pixel. The exposure time control circuit 1610 may include the row driver 520 and the timing generator 530.
[0205]
[0206] The row driver 520 generates control signals corresponding to a long-sequence and/or a short-sequence in response to the first exposure time control signals. The long-sequence means a sequence for controlling a long-exposure time, and the short-sequence means a sequence for controlling a short-exposure time.
[0207] According to another example embodiment, the timing generator 530 may check binning condition data corresponding to binning conditions, generate first exposure time control signals based on a result of the check, and output the generated first exposure time control signals to the row driver 520 (S120). In one embodiment, the timing generator 530 may store the binning condition data (e.g., set during manufacture or programmed by external command received by, for example, a control register block such as control register block 550 shown in
[0208] According to still another example embodiment, the timing generator 530 may generate first exposure time control signals and output generated first exposure time control signals to the row driver 520 based on a result of the check S110 for a current row address and a result of the check S120 for binning condition data. Photoelectric conversion elements, e.g., photodiodes, embodied in each pixel are reset according to a long-sequence and/or a short-sequence (S130).
[0209] Photoelectric conversion elements embodied in each pixel transfer charges integrated or accumulated according to the long-sequence and/or the short-sequence to a corresponding floating diffusion region through transfer transistor. That is, pixels output pixel signals to the analog-digital converter 1630 through column lines after the respective exposure time elapses (S140).
[0210] The analog-digital converter 1630 converts pixel signals output from pixels into digital signals, and transfers the digital signals to the pre-ISP 1650. The pre-ISP 1650 may perform a lens shading correction and/or a bad pixel correction on digital signals, generate color information according to a result of the performing, and output generated color information to the output interface 1670. Moreover, the pre-ISP 1650 may output digital signals or signals corresponding to a result of the performing to the phase difference processing circuit 1660.
[0211] The phase difference processing circuit 1660 may compress the digital signals transferred from the pre-ISP 1650 or signals corresponding to a result of the performing, and output phase difference information corresponding to a result of the compression to the output interface 1670. For example, the phase difference processing circuit 1660 may convert digital signals transferred from the pre-ISP 1650 into Y values (e.g., phase values), detect parity between the digital signals corresponding to long-exposure image signals and the digital signals corresponding to short-exposure image signals, and generate phase difference information corresponding to a result of the detection.
[0212] For example, the phase difference processing circuit 1660 may calculate an average of digital signals corresponding to pixel signals output from pixels included in M rows, where M is a natural number equal to or more than 2 in a Y-axis direction, and generate phase difference information compressed to 1/M.
[0213] The output interface 1670 may output color information output from the pre-ISP 650 and phase difference information output from the phase difference processing circuit 1660. The output interface 1670 may determine an output sequence of the color information and the phase difference information.
[0214]
[0215] The data processing system 700 may include an application processor (AP) 710, an image sensor 505, and a display 730.
[0216] A camera serial interface (CSI) host 713 embodied in the AP 710 may perform a serial communication with a CSI device 706 of the image sensor 505 through a CSI.
[0217] According to an example embodiment, the CSI host 713 may include a de-serializer DES, and the CSI device 706 may include a serializer SER.
[0218] The image sensor 505 may include a plurality of pixels or a plurality of active pixel sensor as described referring to
[0219] In addition, the image sensor 505 may include a control circuit (or an exposure time control circuit), e.g., the row driver, which can independently control exposure time of each of a plurality of photoelectric conversion elements included in each pixel according to a row address and/or binning condition data.
[0220] A display serial interface (DSI) host 711 embodied in the AP 710 may perform a serial communication with a DSI device 731 of the display 730 through a DSI. According to an example embodiment, the DSI host 711 may include the serializer SER and the DSI device 731 may include the de-serializer DES. For example, image data output from the image sensor 505 may be transferred to the AP 710 through a CSI. The AP 710 may process the image data, and transfer processed image data to the display 730 through a DSI.
[0221] The data processing system 700 may further include a RF chip 740 which communicates with the AP 710. A physical layer (PHY) 715 of the AP 700 and a physical layer (PHY) 741 of the RF chip 740 may transmit or receive data to or from each other according to MIPI DigRF.
[0222] The CPU 717 may control an operation of each of the DSI host 711, the CSI host 713, and the PHY 715, and include one or more cores.
[0223] The AP 710 may be embodied in an integrated circuit, and a system on chip (SoC), and may be a processor or a host which can control an operation of the image sensor 505.
[0224] The data processing system 700 may include a GPS receiver 750, a volatile memory 751 such as a dynamic random access memory (DRAM), a data storage device 753 including a non-volatile memory such as a flash-based memory, a mike 755, and/or a speaker 757. The data storage device 753 may be embodied in an external memory which is attachable or detachable to or from the AP 710. In addition, the data storage device 753 may be embodied in a universal flash storage (UFS), a multimedia card (MMC), an embedded MMC (eMMC), or a memory card.
[0225] The data processing system 700 can communicate with an external device using at least one communication protocol, e.g., a worldwide interoperability for microwave access (WiMAX) 759, a Wireless Lan (WLAN) 761, a ultra-wideband (UWB) 763, and/or a long term evolution (LTE) 765. According to an example embodiment, the data processing system 700 may further include a near-field communication (NFC) module, a Wi-Fi module, and/or a Bluetooth module.
[0226] An image sensor according to an example embodiment of the present inventive concepts may include a plurality of photoelectric conversion elements which are independently controlled in each pixel, and have their exposure times or integration times independently controlled. The image sensor including a pixel array can uniformly detect phase difference signals in an entire region of the pixel array using a plurality of photoelectric conversion elements included in each pixel disposed in the pixel array.
[0227] An image quality of generated color images can be improved by the image sensor capable of processing phase difference signals which are uniformly detected. Moreover, reliability of phase difference signals detected by the image sensor is increased and a spatial resolution of the image sensor is increased, such that an auto-focus performance of the image sensor is improved.
[0228] Although a few embodiments of the present general inventive concepts have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concepts, the scope of which is defined in the appended claims and their equivalents.