Light detection device

Abstract

The present invention aims to improve the distance measurement accuracy using Z pixels of the same size as visible light pixels. In a light detection device comprising: a first pixel group including a first floating diffusion region and a first, second, third and fourth photoelectric conversion unit configured to detect visible light in a plan view, wherein the first, second, third and fourth photoelectric conversion unit share the first floating diffusion region; and a second pixel group including a second floating diffusion region and a fifth, sixth, seventh and eighth photoelectric conversion unit configured to detect infrared light in the plan view, wherein the fifth, sixth, seventh and eighth photoelectric conversion unit share the second floating diffusion region.

Description

[0001] This application is a divisional application of patent application No. 201680010038.4, filed on March 4, 2016, entitled "Solid-State Imaging Apparatus, Imaging System and Ranging Method". Technical Field

[0002] This technology relates to solid-state imaging devices, imaging systems, and ranging methods. More specifically, the present invention relates to solid-state imaging devices, imaging systems, and ranging methods for such devices and systems, having ranging pixels for measuring distances to an object. Background Technology

[0003] In related fields, imaging systems are used that measure the distance to an object by illuminating it with infrared light, receiving the reflected infrared light, and measuring the time from illumination to light reception. This method is called the "time-of-flight (TOF)" method and is widely used for motion detection of objects or for measuring three-dimensional shapes. The imaging elements used in such systems include visible light pixels and infrared light pixels. The visible light pixels have photoelectric conversion elements that convert visible light into electrical signals, and the infrared light pixels have photoelectric conversion elements that convert reflected infrared light into electrical signals. Distance is measured using these infrared light pixels. In this document, these infrared light pixels are referred to as ranging pixels. Typically, because infrared light attenuates during propagation, the sensitivity of photoelectric conversion becomes insufficient when using infrared light pixels with the same size as visible light pixels, leading to decreased ranging accuracy. To prevent this, it is desirable to use ranging pixels with high sensitivity. Therefore, ranging pixels using photoelectric conversion elements with a light-receiving area four times larger than that of the photoelectric conversion elements of visible light pixels have been proposed (see, for example, Patent Document 1).

[0004] Reference List

[0005] Patent Document 1

[0006] Patent Document 1: U.S. Patent Application Publication No. 2006 / 0192086 Summary of the Invention

[0007] Technical issues

[0008] In the aforementioned related technologies, a single-photon avalanche diode (SPAD) is used as the photoelectric conversion element, and this SPAD element is constructed with a light-receiving area four times larger than that of a visible light pixel's photoelectric conversion element. This allows for distance measurement using weak reflected light by improving the sensitivity of photoelectric conversion. However, because a ranging pixel with a larger area than a visible light pixel is required, the imaging element must be manufactured according to design principles different from those of ordinary imaging elements. Therefore, high cost is a problem.

[0009] This technology was created in view of the above circumstances, and it is expected to improve the accuracy of ranging by using ranging pixels that are constructed to be the same size as visible light pixels.

[0010] Technical solution

[0011] This technology aims to solve the aforementioned problems. According to a first aspect of this technology, a solid-state imaging device includes: a visible light conversion block comprising a visible light charge holding unit and a plurality of visible light conversion units, wherein a light-receiving surface for receiving visible light in the plurality of visible light conversion units is configured and constructed to generate charge based on the amount of received visible light, and the visible light charge holding unit is configured to exclusively hold the charges generated by the plurality of visible light conversion units respectively during different periods; and an infrared light conversion block comprising an infrared light charge holding unit and a plurality of infrared light conversion units, wherein a light-receiving surface having a size substantially the same as the size of the light-receiving surface of the visible light conversion unit and configured to receive infrared light is configured and constructed to generate charge based on the amount of received infrared light, and the infrared light charge holding unit is configured to jointly and simultaneously hold the charges generated by the plurality of infrared light conversion units respectively. Thus, the effect of simultaneously and jointly holding the charges generated by the plurality of infrared light conversion units is provided.

[0012] Furthermore, according to the first aspect, the visible light conversion block may include the visible light charge retention unit and four visible light conversion units. This provides the effect that the aforementioned visible light conversion block has four visible light conversion units.

[0013] Furthermore, according to the first aspect, the infrared light conversion block includes the infrared light charge retention unit and four infrared light conversion units. Thus, the aforementioned infrared light conversion block provides the effect of having four infrared light conversion units.

[0014] Furthermore, according to the first aspect, the infrared light conversion block may include: two infrared light conversion units; two visible light conversion units; and an infrared charge retention unit configured to simultaneously and jointly retain the charges generated by the two infrared light conversion units while retaining the charges generated by the two infrared light conversion units, and to exclusively retain the charges generated by the two visible light conversion units at different times while retaining the charges generated by the two visible light conversion units. Thus, the aforementioned infrared light conversion block is provided to have the effect of having two infrared light conversion units and two visible light conversion units.

[0015] Furthermore, according to the first aspect, the visible light conversion block may include the visible light charge retention unit and four visible light conversion units, wherein the red light conversion unit configured to generate charge based on red light, the green light conversion unit configured to generate charge based on green light, and the blue light conversion unit configured to generate charge based on blue light are arranged in the form of a Bayer array. Thus, the aforementioned visible light conversion block provides the effect of having four visible light conversion units arranged in a Bayer array.

[0016] Furthermore, according to the first aspect, the visible light conversion block may include: a red light conversion unit configured to generate charge based on red light, a green light conversion unit configured to generate charge based on green light, a blue light conversion unit configured to generate charge based on blue light, a white light conversion unit configured to generate charge based on white light; and the visible light charge holding unit. Thus, the aforementioned visible light conversion block is provided to have the effect of including four visible light conversion units: the aforementioned red light conversion unit, the aforementioned green light conversion unit, the aforementioned blue light conversion unit, and the aforementioned white light conversion unit.

[0017] Furthermore, according to the first aspect, the infrared light conversion block may further include an infrared light charge transfer unit, which is configured to transfer the charge generated by the plurality of infrared light conversion units to the infrared light charge retention unit by simultaneously conducting electricity between the plurality of infrared light conversion units and the infrared light charge retention unit. This provides the effect that the charge generated by the plurality of infrared light conversion units is simultaneously transferred to the infrared light retention unit.

[0018] Furthermore, according to the first aspect, the solid-state imaging device may further include an infrared light signal generation unit configured to generate a signal based on the charge held in the infrared light charge holding unit. This provides the effect of generating a signal based on the charge held in the infrared light charge holding unit.

[0019] Furthermore, according to a second aspect of the present technology, an imaging system includes: an infrared light emitting unit configured to emit infrared light toward a subject; a visible light conversion block including a visible light charge holding unit and a plurality of visible light conversion units, wherein a light receiving surface for receiving visible light in the plurality of visible light conversion units is configured and configured to generate a charge according to the amount of visible light received, and the visible light charge holding unit is configured to exclusively hold the charges generated by the plurality of visible light conversion units respectively during different periods; and an infrared light conversion block including an infrared light charge holding unit and a plurality of infrared light conversion units, wherein the plurality of infrared light conversion units has a component corresponding to the visible light conversion unit. The light-receiving surfaces are substantially the same size, and are configured to generate charge based on the amount of infrared light received, which is then reflected by the subject. The infrared charge holding units are configured to collectively and simultaneously hold the charges generated by the plurality of infrared light conversion units. An infrared signal generation unit is configured to generate a signal based on the charge held in the infrared charge holding units. A distance measurement unit is configured to measure the distance to the subject by measuring the time from emission at the infrared light emitting unit to reception at the infrared light conversion unit in the infrared light conversion block based on the generated signal. This provides the effect that the charges generated by the plurality of infrared light conversion units are simultaneously and collectively held.

[0020] Furthermore, according to a third aspect of the present technology, a ranging method includes: an infrared light emission step of emitting infrared light toward a photographing object; and an infrared light signal generation step of generating a signal based on a charge held in an infrared light charge retention unit in an infrared light conversion block comprising a plurality of infrared light conversion units, wherein the plurality of infrared light conversion units have a light receiving surface having a size substantially the same as that of a light receiving surface of a visible light conversion unit in a visible light conversion block, and the light receiving surface receiving both emitted and reflected infrared light from the photographing object is configured and constructed to generate a charge based on the amount of infrared light received, and the infrared light charge retention unit is configured to jointly and simultaneously retain a charge held by the infrared light emitted and reflected by the photographing object. The visible light conversion block includes a visible light charge holding unit and multiple visible light conversion units, each generating a charge. In each visible light conversion unit, a light-receiving surface for receiving visible light is configured to generate a charge based on the amount of visible light received. The visible light charge holding unit is configured to exclusively hold the charges generated by the multiple visible light conversion units at different times. A ranging step is performed to measure the distance to the subject by measuring the time from the emission of the infrared light to the light reception at the infrared light conversion unit in the infrared light block based on the generated signal. This provides the effect that the charges generated by the multiple infrared light conversion units are simultaneously and jointly held.

[0021] Beneficial effects

[0022] According to this technology, the following preferred and beneficial effects can be provided: improving ranging accuracy by using ranging pixels having the same size as visible light pixels. Furthermore, the effects described herein are not limiting and can be any effect described in this specification. Attached Figure Description

[0023] Figure 1 This is a diagram illustrating an example of the construction of imaging system 1 in an embodiment of the present technology.

[0024] Figure 2 This is a diagram illustrating a construction example of a solid-state imaging device 20 in an embodiment of the present technology.

[0025] Figure 3 This is a diagram illustrating an example of pixel construction in a first embodiment of the present technology.

[0026] Figure 4 This is a diagram illustrating an example of pixel arrangement in a first embodiment of the present technology.

[0027] Figure 5 This is a schematic diagram illustrating an example of pixel construction in a first embodiment of the present technology.

[0028] Figure 6 This is a diagram illustrating the ranging method in the first embodiment of the present technology.

[0029] Figure 7 This is a diagram illustrating the infrared light conversion block in a first embodiment of the present technology.

[0030] Figure 8 This is a diagram illustrating the relationship between the imaging period and the ranging period in a first embodiment of the present technology.

[0031] Figure 9 This is a diagram illustrating the imaging method in the first embodiment of the present technology.

[0032] Figure 10 This is a diagram illustrating the ranging method in the first embodiment of the present technology.

[0033] Figure 11 This is a diagram illustrating an example of the processing steps for distance measurement in a first embodiment of the present technology.

[0034] Figure 12 This is a diagram illustrating a visible light conversion block in a modified example of the first embodiment of the present technology.

[0035] Figure 13 This is a diagram illustrating the infrared light conversion block in a second embodiment of the present technology.

[0036] Figure 14 The diagram illustrates the relationship between the imaging period and the ranging period in a second embodiment of this technology.

[0037] Figure 15 This is a diagram illustrating the imaging method in a second embodiment of the present technology.

[0038] Figure 16 This is a diagram illustrating the infrared light conversion block in the third embodiment of the present technology.

[0039] Figure 17 This is a diagram illustrating the ranging method in the third embodiment of the present technology.

[0040] Figure 18 This is a diagram illustrating the imaging method in the third embodiment of the present technology.

[0041] Figure 19 This is a diagram illustrating the infrared light conversion block in the fourth embodiment of the present technology.

[0042] Figure 20 This is a diagram illustrating an example of pixel arrangement in the fifth embodiment of the present technology.

[0043] Figure 21 This is a diagram illustrating an example of pixel construction in a fifth embodiment of the present technology.

[0044] Figure 22 This is a diagram illustrating the imaging method in the fifth embodiment of the present technology. Detailed Implementation

[0045] The embodiments of the present technology (hereinafter referred to as embodiments) will now be described with reference to the accompanying drawings. The description is performed in the following order.

[0046] 1. First embodiment (example in which two infrared light conversion pixels and two visible light conversion pixels are set in the infrared light conversion block)

[0047] 2. Second embodiment (example in which four infrared light conversion pixels are provided in the infrared light conversion block)

[0048] 3. Third embodiment (example in which one infrared light conversion pixel and three visible light conversion pixels are set in the infrared light conversion block)

[0049] 4. Fourth embodiment (example in which the infrared light conversion pixel is arranged at the position of the G pixel in the Bayer array)

[0050] 5. Fifth Embodiment (Example in the case where two charge retention units are connected to the photoelectric conversion unit)

[0051] <1. First Embodiment>

[0052] [Composition of an Imaging System]

[0053] Figure 1 This is a diagram illustrating an example of the construction of an imaging system 1 in an embodiment of the present technology. The imaging system 1 includes a lens 10, a solid-state imaging device 20, a signal processing unit 30, an image processing unit 40, a distance measurement unit 50, and an infrared light emitting unit 60.

[0054] Lens 10 optically forms an image of the object to be photographed onto solid-state imaging device 20. Solid-state imaging device 20 converts the optical image formed by lens 10 into an image signal and outputs the image signal. In solid-state imaging device 20, pixels for generating image signals are arranged in a two-dimensional manner on the plane forming the optical image. Pixels include visible light pixels for visible light in the optical image and infrared light pixels for infrared light.

[0055] Visible light pixels are pixels used to generate signals based on received visible light, and examples of visible light pixels can include three types of pixels: pixels used to generate signals based on red light (R pixels), pixels used to generate signals based on green light (G pixels), and pixels used to generate signals based on blue light (B pixels). The visible light signals (signals generated by these pixels) are used to form an image signal of the photographed subject.

[0056] Meanwhile, the infrared light pixel is a pixel used to generate an infrared signal, which is a signal based on the received infrared light. In this embodiment of the technology, the infrared light pixel receives infrared light emitted from the infrared light emitting unit 60 (described later) and reflected by the object being photographed, and generates an infrared light signal. The distance to the object being photographed is measured by measuring the time from the emission of the infrared light to the reception of the infrared light. The infrared light pixel corresponds to the ranging pixel described above (hereinafter also referred to as the Z pixel). Details of the construction of the solid-state imaging device 20 and the distance measurement will be described below.

[0057] The signal processing unit 30 processes the image signal output from the solid-state imaging device 20. The signal processing unit 30 separates the image signal output from the solid-state imaging device 20 into visible light signals and infrared light signals, and outputs the visible light signals and infrared light signals to the image processing unit 40 and the distance measurement unit 50, respectively. Furthermore, the signal processing unit 30 also controls the solid-state imaging device 20.

[0058] The image processing unit 40 performs image processing on the visible light signal output from the signal processing unit 30. For example, the image processing described above can perform de-mosaic processing for interpolating signals of other colors lacking in the monochromatic visible light signal generated by the solid-state imaging device 20, and processing to convert the visible light signal into a luminance signal and a chromatic aberration signal. The image signal processed by the image processing unit 40 is output to the outside of the imaging system 1, for example, via a signal line (not shown).

[0059] The distance measurement unit 50 measures the distance to the subject based on the infrared light signal output from the signal processing unit 30. Furthermore, the distance measurement unit 50 also controls the infrared light emitting unit 60.

[0060] The infrared light emitting unit 60 emits infrared light to the object being photographed under the control of the distance measuring unit 50.

[0061] [Structure of a solid-state imaging device]

[0062] Figure 2This is a diagram illustrating an example of the construction of a solid-state imaging device 20 in an embodiment of the present technology. The solid-state imaging device 20 includes a pixel array unit 100, a vertical drive unit 200, a horizontal transmission unit 300, and an analog-to-digital converter (ADC) 400.

[0063] The pixel array unit 100 includes visible light pixels, infrared light pixels, and a signal generation unit arranged in a two-dimensional array. These visible light pixels and infrared light pixels each include photoelectric conversion units that generate charges based on visible light and charges based on infrared light, respectively. Furthermore, the signal generation unit converts the charges generated by the photoelectric conversion units into image signals at a predetermined time sequence and outputs the image signals. After a predetermined period of photoelectric conversion, exposure can be performed by generating an image signal based on the charges generated through the photoelectric conversion. Figure 2 The illustration shows an example where a signal generation unit 150 is arranged relative to four pixels (pixels 110, 120, 130, and 140) in a pixel array 100. In this case, charges generated at pixels 110, 120, 130, and 140 are transferred to the signal generation unit 150, and image signals based on these charges are output. The image signals based on the charges generated by the visible light pixels in these pixels are output as visible light signals, and the image signals based on the charges generated by the infrared light pixels are output as infrared light signals.

[0064] Signals used to control the selection of the aforementioned pixels are transmitted via signal line 101. Furthermore, image signals output from signal generation unit 150 are transmitted via signal line 102. These signal lines 101 and 102 are routed in an XY matrix within the pixel array unit 100. That is, a signal line 101 is routed in a shared manner to pixels 110, etc., arranged in the same row, and the outputs of pixels 110, etc., arranged in the same column are shared and routed to a single signal line 102.

[0065] The vertical drive unit 200 generates control signals and outputs them to the pixel array unit 100. The vertical drive unit 200 outputs control signals to all signal lines 101 of the pixel array unit 100. The control signals output from the vertical drive unit 200 include signals for controlling the transmission of charges generated at the aforementioned pixels 110 to the signal generation unit 150, and signals for controlling the generation of image signals at the signal generation unit 150.

[0066] The horizontal transmission unit 300 processes the image signal output from the pixel array unit 100. Output signals corresponding to pixels such as pixel 110 (corresponding to a row of the pixel array unit 100) are simultaneously input to the horizontal transmission unit 300. The horizontal transmission unit 300 performs parallel-to-serial conversion on the input image signal and outputs the converted image signal.

[0067] The analog-to-digital converter 400 converts the image signal output from the horizontal output unit 300 from an analog signal to a digital signal (AD conversion). The AD-converted image signal is output to the outside of the solid-state imaging device 20 via an output buffer (not shown).

[0068] [Circuit structure of a pixel]

[0069] Figure 3 This is a diagram illustrating an example of pixel construction in a first embodiment of the present technology. Figure 3 The diagram illustrates a circuit structure having pixels 110, 120, 130, and 140; a signal generation unit 150; and a charge retention unit 151.

[0070] Pixel 110 includes a photoelectric conversion unit 111, a charge transport unit 113, and an overflow drain 112. Note that the charge transport unit 113 and the overflow drain 112 are made of metal-oxide-semiconductor (MOS) transistors.

[0071] In addition to signal line 101, power line Vdd and ground line are connected to pixel 110. Power is supplied to pixel 110 via power line Vdd and ground line. Furthermore, signal line 101 consists of multiple signal lines (OFD1 and TR1). OFD1 (Overflow Drain 1) is the signal line used to transmit control signals to overflow drain 112. TR1 (Transfer 1) is the signal line used to transmit control signals to charge transfer unit 113. Figure 3 As shown, all these lines are connected to the gate of the MOS transistor. When a voltage above the threshold voltage between the gate and source is input through these signal lines (hereinafter referred to as the ON signal), the corresponding MOS transistor becomes turned on.

[0072] like Figure 3 As shown, the positive terminal of the photoelectric conversion unit 111 is grounded, and the negative terminal is connected to the source of the charge transport unit 113 and the source of the overflow drain 112. The gate and drain of the overflow drain 112 are connected to OFD1 and Vdd, respectively. The gate of the charge transport unit 113 is connected to the signal line TR1, and the drain is connected to one end of the charge holding unit 151.

[0073] The photoelectric conversion element 111 generates and stores a charge corresponding to the amount of light received. The photoelectric conversion element 111 is composed of a photodiode. One of a visible light conversion unit for visible light and an infrared light conversion unit for infrared light corresponds to the photoelectric conversion element 111. As will be explained below, the visible light conversion unit and the infrared light conversion unit can be configured by changing the characteristics of the color filters arranged for each pixel.

[0074] The charge transport unit 113 transfers the charge generated by the photoelectric conversion unit 111 to the charge holding unit 151. The charge transport unit 113 transfers the charge through electrical conduction between the photoelectric conversion unit 111 and the charge holding unit 151.

[0075] The overflow drain 112 discharges the charge generated by the photoelectric conversion unit 111. The overflow drain 112 discharges excess charge generated at the photoelectric conversion unit 111. In addition, through the electrical conduction between the photoelectric conversion unit 111 and Vdd, all the charge accumulated in the photoelectric conversion unit 111 can also be discharged.

[0076] Pixel 120 includes photoelectric conversion unit 121, charge transport unit 122 and overflow drain 123.

[0077] The signal line 101 connected to pixel 120 consists of multiple signal lines (OFD2 and TR2). OFD2 (Overflow Drain 2) is a signal line used to transmit control signals to the overflow drain 123. TR2 (Transfer 2) is a signal line used to transmit control signals to the charge transfer unit 122. OFD2 and TR2 are connected to the overflow drain 123 and the gate of the charge transfer unit 122, respectively. Since the other structures of pixel 120 are similar to those of pixel 110, their descriptions will be omitted.

[0078] Pixel 130 includes photoelectric conversion unit 131, charge transport unit 133 and overflow drain 132.

[0079] The signal line 101 connected to pixel 130 consists of multiple signal lines (OFD3 and TR3). OFD3 (Overflow Drain 3) is a signal line used to transmit control signals to the overflow drain 132. TR3 (Transfer 3) is a signal line used to transmit control signals to the charge transfer unit 133. OFD3 and TR3 are connected to the gates of the overflow drain 132 and the charge transfer unit 133, respectively. Since the other structures of pixel 130 are similar to those of pixel 110, their descriptions will be omitted.

[0080] Pixel 140 includes photoelectric conversion unit 141, charge transport unit 142 and overflow drain 143.

[0081] The signal line 101 connected to pixel 140 consists of multiple signal lines (OFD4 and TR4). OFD4 (Overflow Drain 4) is a signal line used to transmit control signals to the overflow drain 143. TR4 (Transfer 4) is a signal line used to transmit control signals to the charge transfer unit 143. OFD4 and TR4 are connected to the gates of the overflow drain 143 and the charge transfer unit 142, respectively. Since the other structures of pixel 140 are similar to those of pixel 110, their descriptions will be omitted.

[0082] The charge holding unit 151 holds the charge transferred from pixels 110, 120, 130 and 140.

[0083] The signal generation unit 150 generates a signal corresponding to the signal held in the charge holding unit 151. The signal generation unit 150 includes MOS transistors 152 to 154.

[0084] Signal lines 101 and 102, power line Vdd, and ground are connected to signal generation unit 150. Signal line 101 consists of multiple signal lines (RST and SEL). RST (reset) is the signal line used to transmit control signals to MOS transistor 152. SEL (select) is the signal line used to transmit control signals to MOS transistor 154. Signal line 102 is the signal line used to transmit signals generated by signal generation unit 150.

[0085] like Figure 3 As shown, the drains of MOS transistor 152 and MOS transistor 153 are connected to Vdd. The source of MOS transistor 152 and the gate of MOS transistor 153 are connected to one end of charge holding unit 151 that is connected to the drain of charge transport units 113, 122, 133, and 142. The other end of charge holding unit 151 is grounded. The source of MOS transistor 153 is connected to the drain of transistor 154, and the source of MOS transistor 154 is connected to signal line 102. The gates of MOS transistor 152 and MOS transistor 154 are connected to signal lines RST and SEL, respectively.

[0086] MOS transistor 153 is a MOS transistor that generates a signal corresponding to the charge held in charge retention unit 151. MOS transistor 154 is a MOS transistor that outputs the signal generated by MOS transistor 153 to signal line 102 as an image signal. Note that a constant current source (not shown) is connected to signal line 102 and, together with MOS transistor 153, forms a source follower circuit. The constant current source is arranged in reference... Figure 2 The horizontal transmission unit 300 is described.

[0087] MOS transistor 152 is a MOS transistor that discharges the charge held in charge holding unit 151. MOS transistor 152 discharges the charge through electrical conduction between charge holding unit 151 and Vdd.

[0088] [Pixel-level operations]

[0089] Pixel 110 will be used as an example. Figure 3 The operation of the pixel is illustrated in the diagram. First, when an ON signal is input from OFG, the overflow drain 112 becomes conductive, and Vdd is applied to the negative terminal of photoelectric conversion unit 111. This discharges the charge accumulated in photoelectric conversion unit 111. Then, a charge corresponding to the amount of light received is regenerated and accumulated in photoelectric conversion unit 111.

[0090] When an ON signal is input from TR1 after a predetermined exposure period, the charge transfer unit 113 becomes conductive. This connects the photoelectric conversion unit 111 and the charge retention unit 151, and the charge accumulated in the photoelectric conversion unit 111 is transferred to and retained in the charge retention unit 151. Since the gate of the MOS transistor 153 is connected to the charge retention unit 151, a signal based on the charge retained in the charge retention unit 151 is generated. In this case, if an ON signal is input from SEL, the MOS transistor 154 becomes conductive, and the signal generated by the MOS transistor 153 is output to the signal line 102.

[0091] Subsequently, when an ON signal is input from RST and the MOS transistor 152 becomes on, Vdd is applied to the charge holding unit 151, and the held charge is discharged.

[0092] The sources of charge transport units 113, 122, 133, and 142 are commonly connected to charge retention unit 151. Therefore, by controlling TR1 to TR4 of charge transport units 113, 122, 133, and 142, an image signal based on the charge generated at the desired pixel in pixels 110, 120, 130, and 140 can be generated and output.

[0093] As described above, the operation of each pixel is not different from the others. However, by changing the characteristics of the photoelectric conversion units (photoelectric conversion units 111, 121, 131, and 141), each pixel can be used as a visible light pixel or an infrared light pixel. Specifically, by changing the color filters arranged in each pixel, the characteristics of the photoelectric conversion unit can be changed. Such color filters are filters that select the light to be incident on the photoelectric conversion unit. By arranging color filters that transmit only visible light, the photoelectric conversion unit can be made into a visible light conversion unit for visible light, and the pixel having such a visible light conversion unit can be made into a visible light pixel. At the same time, when a color filter that transmits only infrared light is arranged, the photoelectric conversion unit can be made into an infrared light conversion unit for infrared light, and the pixel having such an infrared light conversion unit can be made into an infrared light pixel. The arrangement of the color filters will be described in detail below.

[0094] In this paper, the charge-preserving unit and the multiple photoelectric conversion units connected to the charge-preserving unit will be referred to as the conversion block. Figure 3 The illustration shows an example of a conversion block consisting of a charge retention unit 151 and four photoelectric conversion units (photoelectric conversion units 111, 121, 131, and 141). Among these conversion blocks, the conversion block having multiple visible light conversion units is referred to as a visible light conversion block. Furthermore, the conversion block having multiple infrared light conversion units is referred to as an infrared light conversion block. Additionally, the charge retention unit in the visible light conversion block is referred to as a visible light charge retention unit, and the charge retention unit in the infrared light conversion block is referred to as an infrared light charge retention unit. As will be described later, the visible light charge retention unit exclusively retains the charge generated by the multiple visible light conversion units at different times. On the other hand, the infrared light charge retention unit simultaneously and jointly retains the charge generated by the multiple infrared light conversion units. The signal generation unit 150 for generating a signal corresponding to the charge retained in the infrared light charge retention unit will be referred to as an infrared light signal generation unit.

[0095] [Pixel arrangement]

[0096] Figure 4 This is a diagram illustrating an example of pixel arrangement in a first embodiment of the present technology. Figure 4 This is a floor plan with four conversion zones. Additionally, it will... Figure 4 The conversion block and reference in the upper left corner Figure 3 The description will be provided in relation to pixels, etc. However, the description of overflow drains 112, 123, 132, and 143 will be omitted. Figure 4As shown, charge retention units 151 are arranged in the center of pixels 110, 120, 130, and 140. Charge transfer units 113, 122, 133, and 142 of each pixel are arranged adjacent to charge retention units 151, and photoelectric conversion units 111, 121, 131, and 141 are arranged adjacent to these charge transfer units. Signal generation unit 150 is arranged adjacent to each of these conversion blocks. If... Figure 4 When the photoelectric conversion units 111, 121, 131, and 141 shown are illuminated by light from the subject being photographed, photoelectric conversion is performed. That is, in the photoelectric conversion units 111, etc., Figure 4 The area shown corresponds to a light-receiving surface that receives visible light, etc.

[0097] Furthermore, color filters 119, 129, 139, and 149 are arranged in the pixels respectively. The letters R, G, B, and Z marked on each pixel indicate the type of color filter. Here, the color filters 129 and 149 of pixels 120 and 140, marked with the letter Z, are color filters that transmit infrared light. Therefore, photoelectric conversion units 111 and 131 and... Figure 4 In the conversion block at the lower left, photoelectric conversion units 161, 171, 181, and 191 correspond to visible light conversion units, and pixels 110, 130, 160, 170, 180, and 190 having these visible light conversion units correspond to visible light pixels. Simultaneously, photoelectric conversion units 121 and 141 correspond to infrared light conversion units, and pixels 120 and 140 having these infrared light conversion units correspond to infrared light pixels. Figure 4 It is clear that the light-receiving surface of the infrared light conversion unit has essentially the same dimensions as the light-receiving surface of the visible light conversion unit.

[0098] also, Figure 4 The upper left conversion block includes two infrared light conversion units (photoelectric conversion units 121 and 141), two visible light conversion units (photoelectric conversion units 111 and 131), and an infrared light charge retention unit (charge retention unit 151), corresponding to the infrared light conversion block. Furthermore, a signal generation unit 150 arranged adjacent to this conversion block corresponds to an infrared light signal generation unit that generates a signal corresponding to the charge retained in the infrared light charge retention unit (charge retention unit 151). Similarly, Figure 4 The conversion block in the upper right corner also corresponds to the infrared light conversion block. Meanwhile, Figure 4 The conversion block in the lower left corner includes four visible light conversion units (photoelectric conversion units 161, 171, 181, and 191) and a visible light charge retention unit (charge retention unit 159), and corresponds to the visible light conversion block. Similarly, Figure 4The lower right conversion block in the image also corresponds to the visible light conversion block. In such a visible light conversion block, R, G, and B pixels are arranged in a Bayer array.

[0099] [Cross-section of a pixel]

[0100] Figure 5 This is a schematic diagram illustrating an example of pixel construction in a first embodiment of the present technology. Figure 5 It is along Figure 4 A cross-sectional view taken from line A-A'. Pixels 110 and 140 will be used as examples for illustration. Figure 5 The photoelectric conversion units 111 and 141 are respectively composed of a p-type semiconductor region 517 and n-type semiconductor regions 511 and 512 embedded within the p-type semiconductor region 517. Photoelectric conversion occurs at the pn junction formed at the interface between these semiconductor regions, and a charge corresponding to the amount of light received is generated. In this case, electrons in the generated charge are stored in the n-type semiconductor regions 511 and 512. Above the photoelectric conversion unit, a color filter 119 or 149, a planarization film 503, and a microlens 501 are arranged in sequence. The planarization film 503 planarizes the surface of the pixel. The microlens 501 is a lens that focuses the light incident on the pixel onto the photoelectric conversion unit. A light-shielding film 502 is arranged between the color filters 119 and 149. The light-shielding film 502 blocks light incident obliquely from adjacent pixels.

[0101] Furthermore, in the p-type semiconductor region 517, a separating region 513 is arranged between pixels. The separating region 513 is a region used to separate pixels and block light incident obliquely from adjacent pixels. A charge holding unit 151 is arranged in the middle portion between pixels 110 and 140. The charge holding unit 151 is composed of an n-type semiconductor region 514. The n-type semiconductor region 514 is a region called a floating diffusion region (FD) and is connected to the signal generation unit 150 (not shown). Figure 5 As shown, the charge holding unit 151 is positioned directly below the partition region 513 and is therefore shielded from light by the partition region 513. Charge transport units 113 and 142 are arranged between the charge holding unit 151 and the photoelectric conversion units 111 and 141. Gate electrodes 515 and 516 are respectively arranged at the charge transport units 113 and 142. When an ON voltage is applied to the gate electrodes, the p-type semiconductor region 517 located between the photoelectric conversion unit 111 or 141 and the charge holding unit 151 becomes conductive, and the charge transport units 113 and 142 also become conductive.

[0102] An interlayer insulating layer 519 and a wiring layer 518 are disposed below the p-type semiconductor region 517. The wiring layer 518 transmits signals from pixels 110 and 140 and constitutes a reference. Figure 3The signal lines 101 and 102 are described. The interlayer insulation layer 519 insulates the wiring layers 518 from each other.

[0103] In this way, due to the direction of the shot Figure 5 The light in the charge holding unit 151 is blocked by the partition region 513, thus reducing the dark current.

[0104] [Principles of Distance Measurement]

[0105] Figure 6 This is a diagram illustrating the ranging method in the first embodiment of the present technology. Figure 6 The emitted infrared light has the waveform of infrared light emitted from the infrared light emitting unit 60. Furthermore, the reflected infrared light has the waveform of infrared light obtained when the emitted infrared light is reflected by the object being photographed and incident on the solid-state imaging device 20. The Z-pixel of the solid-state imaging device 20 receives the reflected infrared light, converts the reflected infrared light into an infrared light signal, and performs exposure. In this case, two Z-pixels are used to set different exposure periods and generate infrared light signals. The first exposure period and the second exposure period represent the relationship between the exposure periods set by the two Z-pixels, and the period of the binarized value "1" of the waveform corresponds to the exposure period.

[0106] like Figure 6 As shown, the pulse width of the emitted infrared light is modulated to a 50% duty cycle and the emitted infrared light is emitted from the infrared light emitting unit 60. Simultaneously, the reflected infrared light has a waveform with a phase delay relative to the emitted infrared light. Figure 6 In this context, D represents the phase delay. This corresponds to the time from when the emitted infrared light is reflected by the object being photographed until the emitted infrared light reaches the solid-state imaging device 20. By measuring this time, the distance to the object can be calculated.

[0107] The exposure period is set to be synchronized with the emitted infrared light as... Figure 6 The first exposure period is defined as follows. Simultaneously, an exposure period with a phase shift of 180° relative to the emitted infrared light is defined as the second exposure period. During the first exposure period, in... Figure 6 During period 701, the reflected light undergoes photoelectric conversion. During the second exposure period, Figure 6 The reflected light undergoes photoelectric conversion during period 702. The ratio of period 701 to period 702 changes according to the phase delay. That is, as the phase delay D increases, period 701 becomes shorter, while period 702 becomes longer. Therefore, the phase delay D can be calculated by calculating the ratio of the infrared light signal generated by the Z pixel during the first exposure period and the second exposure period.

[0108] Here, when the infrared light signals of the Z pixel during the first exposure period and the second exposure period are set to S1 and S2 respectively, and the period of the emitted infrared light is T, D can be calculated using the following formula.

[0109] D = S2 × (S1 + S2) × T / 2

[0110] The distance L to the subject can be calculated using the following formula.

[0111] L = D × c / 2 (Formula 1)

[0112] Where c is the speed of light. For example, when the distance to the subject is 10 meters, D is approximately 33 ns. In this case, by setting T to, for example, 100 ns (the modulation frequency of the emitted infrared light is 10 MHz), the distance can be measured. (Based on reference...) Figure 1 The distance measurement unit 50 described herein controls the output of pulse-modulated infrared light from the infrared light emitting unit 60 and calculates the distance.

[0113] In this way, the distance to the subject can be calculated using two Z pixels. Note that because reflected infrared light attenuates during propagation, it is necessary to repeatedly emit infrared light and accumulate the charge generated by the Z pixels to increase the level of the infrared light signal.

[0114] [Operation of Solid-State Imaging Devices]

[0115] Figure 7 This is a diagram illustrating the infrared light conversion block in a first embodiment of the present technology. Figure 7 The arrangement of pixels in the reference is similar to that in the image. Figure 4 The arrangement of pixels is explained. This is achieved by arranging them in... Figure 7 Distance is measured by a pixel group 660 formed by the Z pixels (Za, Zb, Zc, and Zd) in the two upper infrared light conversion blocks 620 and 630. Za and Zc belong to different infrared light conversion blocks than Zb and Zd and are connected to different infrared charge holding units 621 and 631. A reference is used for Za and Zc compared to Zb and Zd. Figure 6 The distance is measured using the first and second exposure periods, as described. Meanwhile, Figure 7 The visible light conversion block 610 includes a visible light charge retention unit 611. The visible light conversion block 610 is configured to perform imaging using visible light.

[0116] Figure 8 This is a diagram illustrating the relationship between the imaging period and the ranging period in a first embodiment of this technology. (See diagram for example.) Figure 8As shown, the solid-state imaging device 20 measures the distance to the subject after imaging to generate an image signal for the subject. The imaging period and the ranging period, which are the periods used for imaging and distance measurement, are repeated alternately. During the imaging period, reset, exposure, and signal output are sequentially performed within the visible light pixels, starting from the first line. Here, reset refers to discharging the charge accumulated in the photoelectric conversion unit. All pixels in a row are reset, and exposure begins. After a predetermined exposure period, an image signal based on the charge generated by photoelectric conversion is generated and output. Thus, the exposure of that row ends. By performing the above process on all rows, one frame (which corresponds to an image signal for one screen) can be obtained. Then, the process moves to the ranging period.

[0117] During the ranging process, reset, exposure, and signal output are sequentially performed in the infrared light pixels, starting from the first line. In this case, an infrared light signal for distance measurement is generated and output.

[0118] [Imaging Methods]

[0119] Figure 9 This is a diagram illustrating an imaging method according to a first embodiment of the present technology. Figure 9 The imaging method of the visible light conversion region 610 is illustrated, and the relationship between the input signal and the output signal is also illustrated. Figure 9 The signal shown corresponds to the reference. Figure 3 The signals mentioned above. In these signals, in the input signals, the period during which the value of the binarized waveform is "1" corresponds to the input of the ON (conduct) signal. Furthermore, references will be used... Figure 3 The same reference numerals are used to describe the reference numerals for components other than the visible light charge holding unit 611 (charge transport unit and overflow drain).

[0120] First, an ON signal is input to OFD1 through OFD4, causing overflow drains 112, 123, 132, and 143 to conduct (T1). This discharges the charge accumulated in photoelectric conversion units 111, 121, 131, and 141, and performs a reset. After the reset, the ON signal input to OFD1 through OFD4 is stopped, de-conducting overflow drains 112, 123, 132, and 143 (T2). This regenerates and accumulates the charge obtained through photoelectric conversion in photoelectric conversion units 111, 121, 131, and 141. That is, exposure begins.

[0121] After a predetermined exposure period, an ON signal is input to RST to turn on the MOS transistor 152 of the signal generation unit 150 (T3). This discharges the charge in the visible light charge holding unit 611. Simultaneously, an ON signal is input to SEL to turn on the MOS transistor 154 of the signal generation unit 150. Thus, when charge is transferred to and held in the visible light charge holding unit 611 during subsequent operations, a visible light signal based on that charge is output to the signal line 102.

[0122] Next, the ON signal is stopped from being input to RST to de-conduct the MOS transistor 152, and the ON signal is input to TR1 to turn on the charge transfer unit 113 of pixel 110 (T4). As a result, the charge accumulated in the photoelectric conversion unit 111 is transferred to the visible light charge retention unit 611. Furthermore, a signal "G" based on the charge transferred to the visible light charge retention unit 611 is output to the signal line 102. This signal corresponds to the visible light signal (image signal corresponding to green light) at pixel 110. The transfer of the charge accumulated in the photoelectric conversion unit 111 to the visible light charge retention unit 611 stops the exposure period at pixel 110 and shifts processing to the reference. Figure 8 The signal output is explained.

[0123] Next, the ON signal input to TR1 is stopped, and the ON signal is input to RST(T5). As a result, the charge held in the visible light charge holding unit 611 is discharged, and the signal output at pixel 110 ends.

[0124] Next, the ON signal input to RST is stopped, and the ON signal is input to TR2 to turn on the charge transfer unit 122 of pixel 120 (T6). As a result, the charge accumulated in the photoelectric conversion unit 121 is transferred to the visible light charge holding unit 611, and a signal "B" based on the transferred charge is output to the signal line 102. This signal corresponds to the visible light signal (image signal corresponding to blue light) in pixel 120. Then, the ON signal input to TR2 is stopped, and the ON signal is input to RST (T7). This drains the charge from the visible light charge holding unit 611 and terminates the signal output of pixel 120.

[0125] Then, the ON signal input to RST is stopped, and the ON signal is input to TR3 to turn on the charge transfer unit 133 of pixel 130 (T8). As a result, the charge accumulated in the photoelectric conversion unit 131 is transferred to the visible light charge holding unit 611, and a signal "R" based on the transferred charge is output to the signal line 102. This signal corresponds to the visible light signal (image signal corresponding to red light) at pixel 130. Then, the ON signal input to TR3 is stopped, and the ON signal is input to RST (T9). This drains the charge from the visible light charge holding unit 611 and terminates the signal output of pixel 130.

[0126] Then, the ON signal input to RST is stopped, and the ON signal is input to TR4 to turn on the charge transfer unit 142 of pixel 140 (T10). As a result, the charge accumulated in the photoelectric conversion unit 141 is transferred to the visible light charge retention unit 611, and a signal "G" based on the transferred charge is output to the signal line 102. This signal corresponds to the visible light signal (image signal corresponding to green light) at pixel 140. Then, the ON signal input to TR4 and SEL is stopped. This ends the signal output of pixel 140.

[0127] References were made for all lines. Figure 9 After the processing described, the imaging period for one screen ends. In this way, within the visible light conversion block 610, the charges generated by the four photoelectric conversion units 111, 121, 131, and 141 are exclusively held in the visible light charge holding unit 611 during different periods (T4, T6, T8, and T10). That is, the charges generated by the multiple visible light conversion units are exclusively held in the visible light charge holding unit.

[0128] [Distance Measurement]

[0129] Figure 10 This is a diagram illustrating the ranging method in the first embodiment of the present technology. Figure 10 The diagram illustrates the ranging method in pixel group 660. Figure 10 The diagram illustrates the relationship between the input signal at the Z pixel of pixel group 660, the emitted infrared light, the reflected infrared light, and the amount of charge held at infrared charge holding units 621 and 631. Please note the reference... Figure 7 The signals of the infrared light conversion blocks 620 and 630 described correspond to the reference. Figure 3 The signals described. That is, within the Z pixels of pixel group 660, the signals Za and Zc correspond to... Figure 3 The signals at pixels 120 and 140 in the image. Similarly, the signals of Zb and Zd correspond to... Figure 3The signals at pixels 110 and 130 in the image. In addition to the infrared charge holding units 621 and 631, the reference will be used. Figure 3 The same reference numerals are used to describe the components.

[0130] First, an ON signal is input to the RST of infrared light conversion blocks 620 and 630 to turn on MOS transistor 152. Simultaneously, an ON signal is input to OFD2 and OFD4 of infrared light conversion block 620 and OFD1 and OFD3 of infrared light conversion block 630 to turn on overflow drains 123, 143, 112, and 132 (T1). This discharges the charge held in infrared charge holding units 621 and 631. Furthermore, the charge accumulated in photoelectric conversion units 121 and 141 of infrared light conversion block 620 and photoelectric conversion units 111 and 131 of infrared light conversion block 630 is discharged, and a reset is performed. After the reset is complete, the ON signal input to RST and OFD is stopped.

[0131] Then, infrared light is emitted from the infrared light emitting unit 60, and an ON signal is input to TR2 and TR4 of the infrared light conversion block 620, and an ON signal is input to OFD1 and OFD3 of the infrared light conversion block 630. As a result, in the infrared light conversion block 620, charge transfer units 122 and 142 become conductive, and the charge generated based on the emitted infrared light at the photoelectric conversion units 121 and 141 is retained in the infrared light charge retention unit 621. Simultaneously, in the infrared light conversion block 630, overflow drains 112 and 132 become conductive, and photoelectric conversion units 111 and 131 are reset.

[0132] Next, infrared light emission from infrared light emitting unit 60 is stopped, and the ON signal input to TR2 and TR4 of infrared light conversion block 620 and OFD1 and OFD3 of infrared light conversion block 630 is stopped. Simultaneously, the ON signal is input to OFD1 and OFD3 of infrared light conversion block 620 and TR2 and TR4 (T4) of infrared light conversion block 630. As a result, in infrared light conversion block 620, overflow drains 123 and 143 become conductive, and photoelectric conversion units 121 and 141 are reset. Simultaneously, in infrared light conversion block 630, charge transfer units 113 and 133 become conductive, and the charge generated based on reflected infrared light at photoelectric conversion units 111 and 131 is retained in infrared charge holding unit 631.

[0133] Next, the input of ON signals to OFD1 and OFD3 of infrared light conversion block 620 and TR2 and TR4 (T5) of infrared light conversion block 630 is stopped. Thereafter, the operations of T3 and T4 are repeated a predetermined number of times. Thus, charge based on reflected infrared light is accumulated in infrared light charge holding units 621 and 631.

[0134] Next, an ON signal is input to the SEL of infrared light conversion block 620 and the SEL of infrared light conversion block 630. As a result, the MOS transistors 154 of infrared light conversion block 620 and 630 become conductive, and infrared light signals based on the charges held in infrared light charge holding units 621 and 631 are output respectively. Then, the input of the ON signal to the SEL of infrared light conversion block 620 and the SEL of infrared light conversion block 630 is stopped, and the ranging period ends (T7).

[0135] As described above, photoelectric conversion synchronized with the emitted infrared light is performed in Za and Zc of the infrared light conversion block 620. That is, a reference is set in Za and Zc. Figure 6 The first exposure period is described in the diagram. Simultaneously, in the infrared light conversion blocks 630 (Zb and Zd), photoelectric conversion occurs during a period when the phase is shifted by 180° relative to the emitted infrared light. That is, a reference is set in Zb and Zd. Figure 6 During the second exposure period described in the diagram, the distance measurement unit 50 calculates the distance to the subject based on the infrared light signals from these Z pixels.

[0136] In this manner, in the infrared light conversion block 620, charge transport units 122 and 142 simultaneously become conductive, and the charges generated by the two photoelectric conversion units 121 and 141 are simultaneously and jointly held in the infrared light charge holding unit 621 (T3). In this manner, in the infrared light conversion block 630, charge transport units 113 and 133 simultaneously become conductive, and the charges generated by the two photoelectric conversion units 111 and 131 are simultaneously and jointly held in the infrared light charge holding unit 631 (T4). That is, the charges generated by multiple infrared light conversion units are simultaneously and jointly held in the infrared light charge holding unit. Note that charge transport units 122 and 142 are examples of the infrared light charge transport units described in the claims.

[0137] Meanwhile, in the G and R pixels of the infrared light conversion block 620, by adopting a reference... Figure 9The imaging method described generates visible light signals. That is, the charges generated by the visible light conversion units contained in these pixels are selectively held in the infrared charge holding unit 621 during different periods. Charges are similarly held in the B and G pixels of the infrared light conversion block 630.

[0138] [Distance Measurement Steps]

[0139] Figure 11 This diagram illustrates an example of the ranging processing steps in a first embodiment of the present technology. When measuring distance, the process is performed in imaging system 1. Figure 11 The processing in the middle. Will use Figure 7 The symbols shown illustrate the processing steps.

[0140] First, the infrared light emitting unit 60 emits infrared light towards the object being photographed (step S901). Then, the infrared light conversion block 620, which is set with a first exposure period, exposes the infrared light (step S902). After the predetermined exposure period, the charge generated during the exposure is retained in the infrared charge retention unit 621 (step S903). The infrared light emitting unit 60 stops emitting infrared light (step S904). Next, the infrared light conversion block 630, which is set with a second exposure period, exposes the infrared light (step S905), and the generated charge is retained in the infrared charge retention unit 631 (step S906). Then, it is determined whether the predetermined number of exposures has been reached (step S907). If the predetermined number of exposures has not been reached (step S907: No), the process starts again from step S901.

[0141] On the other hand, when the predetermined number of exposures has been reached (step S907: Yes), an infrared light signal based on the charge held in the infrared light charge holding units 621 and 631 is generated (step S908). Finally, the distance measurement unit 50 calculates the distance based on the generated infrared light signal (step S909).

[0142] In the first embodiment of this technology, as shown in reference Figure 7 The exposure is performed with a first exposure period and a second exposure period set for Za and Zc, and Zb and Zd of pixel group 660, respectively. This allows for the simultaneous acquisition of infrared light signals based on both the first and second exposure periods, thus shortening the ranging period. Furthermore, by using two infrared light conversion units with light-receiving surfaces of the same size as the light-receiving surfaces of the visible light conversion units in the visible light pixels and connected in parallel, the sensitivity of the infrared light conversion units can be improved. This is because the sensitivity of the photoelectric conversion unit (i.e., the amount of charge generated per unit time) is proportional to the light-receiving area of ​​the photoelectric conversion unit.

[0143] Sensitivity can also be improved by constructing an infrared light conversion unit with an area twice that of the visible light conversion unit. However, a problem exists: the charge transport unit in a large-area photoelectric conversion unit requires more time to transfer charge. (Referring to...) Figure 5 In the n-type semiconductor region 512 of the described photoelectric conversion unit 141, the accumulated charge is mainly transferred through charge diffusion. On the other hand, in the first embodiment of this technology, as described above, two infrared light conversion units are used, each having a light-receiving surface of the same size as the light-receiving surface of the visible light conversion unit in the visible light pixel. Therefore, the time required to transfer the charge is the same as the time required to transfer the charge in the visible light conversion unit.

[0144] also, Figure 7 The infrared light conversion blocks 620 and 630 are arranged adjacent to each other. Therefore, the infrared light signals generated by these infrared light conversion blocks can be considered as infrared light signals based on the same photographed object. Compared with the case where the infrared light conversion blocks 620 and 630 are arranged separately, the accuracy of distance measurement can be improved.

[0145] Furthermore, the visible light conversion block is formed with four visible light pixels and configured in a Bayer array. Simultaneously, the pixel group 660 in the first embodiment of this technology also forms four Z pixels. This simplifies the arrangement of the Z pixels in the pixel array unit 100. The solid-state imaging device 20 is constructed by replacing the visible light pixels of the pixel array unit 100 with infrared light pixels. In this case, since the number of visible light conversion blocks is the same as the number of pixel groups 660 with Z pixels, it is possible to replace the visible light pixels with infrared light pixels for the entire pixel array unit 100 without changing the ratio of R pixels, G pixels, and B pixels.

[0146] Furthermore, in the first embodiment of this technology, the size of the Z-pixel is formed to be substantially the same as the size of the visible light pixel. Therefore, since the Z-pixel and the visible light pixel can share the same structure in the semiconductor substrate, including the diffusion layer, wiring patterns, etc., except for the structure of the color filter, the Z-pixel and the visible light pixel can be manufactured based on the same design rules.

[0147] In this manner, according to the first embodiment of the present technology, by using two Z pixels having a size substantially the same as that of a visible light pixel side by side, the sensitivity of the Z pixels can be improved. This, in turn, improves the accuracy of ranging.

[0148] [Variation Example]

[0149] In the above embodiments, although the visible light conversion block is constructed with three types of pixels—R pixels, G pixels, and B pixels—as visible light pixels, the visible light conversion block can also be constructed with four types of pixels, including a W pixel for white light. For example, a configuration in which one of the two G pixels in the Bayer array is replaced by a W pixel can be adopted.

[0150] Figure 12 This is a diagram illustrating a modified example of the visible light conversion block of the first embodiment of the present technology. Figure 12 In the diagram, the pixel labeled W corresponds to the W pixel, and a color filter that allows white light to pass through is arranged within that pixel. Furthermore, in... Figure 12 Since the number of visible light conversion blocks 611 is the same as the number of pixel groups 660 forming Z pixels, it is possible to replace visible light pixels with infrared light pixels for the entire pixel array unit 100 without changing the ratio of R pixels, G pixels, B pixels and W pixels.

[0151] <Second Embodiment>

[0152] In the above embodiment, an infrared light conversion block consisting of two Z pixels and two visible light pixels is used to measure distance. In contrast, in a second embodiment of this technology, an infrared light conversion block consisting of four Z pixels is used to measure distance. This reduces the number of signal lines connected to the Z pixels.

[0153] [Operation of Solid-State Imaging Devices]

[0154] Figure 13 This is a diagram illustrating the infrared light conversion block in the second embodiment of the present technology. Figure 13 Infrared light conversion block 620 and reference Figure 7 The difference in the infrared light conversion block 620 described is that all pixels are composed of Z pixels. That is, Figure 13 The infrared light conversion block 620 in the middle adopts the method of... Figure 7 The pixel group 660 formed by the Z pixels is configured to match the pixels of the infrared light conversion block 620. Therefore, in Figure 13 In the infrared light conversion block 620, at the Z-pixel, the charge transfer unit and the overflow drain can operate simultaneously at four pixels. Since the infrared light signal is generated using four Z-pixels, the sensitivity of the Z-pixels can be improved, thereby increasing the accuracy of distance measurement. Because the other components of the solid-state imaging device 20 and imaging system 1 are similar to those in the first embodiment of this technology, their description will be omitted.

[0155] Figure 14This is a diagram illustrating the relationship between the imaging period and the ranging period in the second embodiment of this technology. The ranging period of the second embodiment of this technology is compared with the reference period. Figure 8 The difference in the ranging period described is that the first ranging period and the second ranging period are executed as two ranging periods after the imaging time.

[0156] [Imaging Methods]

[0157] Figure 15 This is a diagram illustrating an imaging method according to a second embodiment of the present technology. The same signal is input to the charge transport units and overflow drains of all Z pixels in the aforementioned infrared light conversion block 620. Due to... Figure 15 The operation during the first and second ranging periods is similar to that of the reference period. Figure 10 The operations in the infrared light conversion blocks 620 and 630 are described, so their description will be omitted.

[0158] In this way, according to the second embodiment of the present technology, distance is measured by using an infrared light conversion block consisting of four Z pixels, and a shared signal can be used as the signal to be supplied to the Z pixels. This reduces the number of signal lines.

[0159] <Third Embodiment>

[0160] In the first embodiment described above, an infrared light conversion block consisting of two Z-pixels and two visible light conversion pixels is used to measure distance. In contrast, in the third embodiment of this technology, an infrared light conversion block consisting of one Z-pixel and three visible light conversion pixels is used to measure distance. In this way, a ranging method can be used that employs an exposure scheme for infrared light reflected in four phases.

[0161] [Operation of Solid-State Imaging Devices]

[0162] Figure 16 This is a diagram illustrating the infrared light conversion block in the third embodiment of the present technology. Figure 16 Infrared light conversion blocks 620, 630, 640, and 650 are compared with reference. Figure 7 The difference between the infrared light conversion blocks 620 and 630 is that each infrared light conversion block 620, 630, 640, and 650 consists of one Z pixel and three visible light conversion pixels. Furthermore, Figure 16 The pixel group 660 formed by the Z pixels is configured to span these four infrared light conversion blocks and to span two lines. Since the other configurations of the solid-state imaging device 20 and imaging system 1 are similar to those of the solid-state imaging device 20 and imaging system 1 in the first embodiment of this technology, their description will be omitted.

[0163] [The principle of distance measurement]

[0164] Figure 17 This is a diagram illustrating the ranging method in the third embodiment of this technology. Figure 17 In the distance measurement method shown, the distance is measured by emitting infrared light with an amplitude modulated by a sine wave and measuring the phase delay of the reflected infrared light. Figure 17 Figure 'a' illustrates the relationship between emitted and reflected infrared light. If the emitted infrared light... Figure 17 In diagram a, denoted along the positive x-axis, the reflected infrared light has a waveform with a phase delay depending on the distance from the subject. If this delay is represented by... Indicate, then It can be expressed by the following formula.

[0165]

[0166] Where q is the peak value of the reflected wave, and r represents the peak value of the reflected wave with a phase advance of 90°.

[0167] Figure 17 Figure b illustrates a method for obtaining q and r. During one cycle of the emitted infrared light, the peak value of the reflected infrared light is measured for each phase at 90°. When these peak values ​​are denoted by p1 to p4, q and r can be expressed by the following formula.

[0168] q = |(p1-p3) / 2|

[0169] r = |(p2-p4) / 2|

[0170] In this way, by calculating the differences between p1 and p3 and between p2 and p4, the influence of infrared light other than the reflected infrared light can be eliminated. The following formula can be used for calculation.

[0171]

[0172] Reference Figure 6 The value of D can be calculated as follows.

[0173]

[0174] Next, the distance L to the subject is calculated using Formula 1. Here, p1 to p4 are obtained by exposing the emitted infrared light with a 90° phase difference for one cycle, accumulating the generated charge, and converting the charge into an infrared light signal. Figure 17 In b, they are represented as the first to fourth exposure periods.

[0175] As mentioned above, in Figure 17In the distance measurement method shown, since the distance is measured by using 4 Z pixels and calculating the difference, the influence of infrared light other than reflected infrared light can be eliminated. Therefore, compared with the reference... Figure 6 Compared to the distance measurement method described above, this method allows for high-precision measurements.

[0176] [Imaging Methods]

[0177] Figure 18 This is a diagram illustrating an imaging method according to a third embodiment of the present technology. Assuming that it is for... Figure 18 Za, Zb, Zc, and Zd are respectively set as references Figure 17 The following describes the process during the first to fourth exposures. First, an ON signal is input to the RST of infrared light conversion blocks 620, 630, 640, and 650 to discharge the charge (T1) held by infrared light charge holding units 621, 631, 641, and 651. Note that the names of the infrared light conversion blocks will be omitted in the following description.

[0178] Simultaneously with the signal input to RST, the ON signal is input to OFD4, OFD3, OFD2, and OFD1, and photoelectric conversion units 111, 121, 131, and 141 are reset. After the reset is complete, the input of the ON signal to RST and OFD1 to OFD4 (T2) is stopped.

[0179] Then, infrared light emission begins, and an ON signal is input to TR4, OFD3, OFD2, and OFD1 (T3). In this way, reflection-based infrared light exposure is performed at pixel 140, and charge is accumulated in the infrared light charge retention unit 621.

[0180] Then, the ON signal input to TR4 and OFD3 is stopped, and the ON signal is input to TR3, OFD4, OFD2, and OFD1 (T4). In this way, exposure to infrared light based on reflection is performed at pixel 130, and charge is accumulated in the infrared light charge holding unit 631.

[0181] Then, the ON signal input to TR3 and OFD2 is stopped, and the ON signal is input to TR2, OFD4, OFD3 and OFD1 (T5). In this way, exposure to infrared light based on reflection is performed at pixel 120, and charge is accumulated in the infrared light charge holding unit 641.

[0182] Then, the ON signal input to TR2 and OFD1 is stopped, and the ON signal is input to TR1, OFD4, OFD3 and OFD2 (T6). In this way, exposure to infrared light based on reflection is performed at pixel 110, and charge is accumulated in the infrared light charge holding unit 651.

[0183] Then, the ON signal input to TR1 and OFD4 (T7) is stopped. Thereafter, the operation from T3 to T6 is repeated a predetermined number of times. In this way, charge based on reflected infrared light is accumulated in infrared charge holding units 621, 631, 641, and 651.

[0184] Then, an ON signal is input to the SEL (T8) of infrared light conversion blocks 620 and 630. In this way, an infrared light signal based on the charge held in infrared light charge holding units 621 and 631 is generated. Then, inputting the ON signal to the SEL of infrared light conversion blocks 620 and 630 is stopped, and an ON signal is input to the SEL (T9) of infrared light conversion blocks 640 and 650. In this way, an infrared light signal based on the charge held in infrared light charge holding units 641 and 651 is generated. (See reference...) Figure 16 As explained, since the pixel group 660 of the Z pixel is configured to span two lines, a SEL signal needs to be input for each line to obtain an infrared light signal. Then, the input of the ON signal to the SEL of the infrared light conversion blocks 640 and 650 is stopped, and the ranging period ends (T10).

[0185] Infrared light signals can be obtained by acquiring infrared light signals based on the charges held in the infrared light charge holding units 621, 631, 641, and 651, as described above. An infrared light signal with a 90° phase shift can then be obtained. The distance measurement unit 50 measures the distance to the object being photographed based on these infrared light signals.

[0186] In this way, according to the third embodiment of the present technology, a ranging method can be performed using the exposure of reflected infrared light to separate four phases. This eliminates the influence of infrared light other than the reflected infrared light, thereby improving the accuracy of distance measurement.

[0187] <Fourth Embodiment>

[0188] In the third embodiment described above, the Z pixels of pixel group 660 are arranged adjacent to each other. Conversely, in the fourth embodiment of this technology, in the infrared light conversion block, the Z pixels are arranged at the positions of the G pixels in the Bayer array. This facilitates de-mosaic processing.

[0189] [Operation of Solid-State Imaging Devices]

[0190] Figure 19 This is a diagram illustrating the infrared light conversion block in the fourth embodiment of the present technology. Figure 19 The infrared conversion blocks 620, 630, 640, and 650 consist of one Z pixel and three visible light conversion pixels. However, Figure 19Infrared light conversion blocks 620, 630, 640, and 650 are compared with reference. Figure 16 The difference between the infrared light conversion blocks 620, 630, 640, and 650 described is that the Z pixel is configured at the position of the G pixel in the Bayer array of each photoelectric conversion block. Since the other configurations of the solid-state imaging device 20 and imaging system 1 are similar to those in the third embodiment of this technology, their description will be omitted. Furthermore, as a ranging method, in a manner similar to the third embodiment of this technology, a ranging method using the exposure of reflected infrared light in a scheme of four separate phases can be used.

[0191] As described above, the image processing unit 40 can perform demosaic processing on the visible light signal output from the solid-state imaging device 20. This demosaic processing is used to interpolate insufficient color signals in each pixel, and when the processing is applied to the Z pixel, it is necessary to interpolate the three corresponding signals for red, green, and blue light. This interpolation can be performed by calculating the average value of the visible light signals output by the visible light pixels arranged around the Z pixel in the visible light pixels corresponding to the corresponding colors. However, for the visible light signal corresponding to green light in the Z pixel, interpolation can be performed using the signal of the G pixel included in the same infrared light conversion block. In this way, the demosaic processing of the visible light signal corresponding to green light can be simplified.

[0192] In this way, according to the fourth embodiment of the present technology, by configuring the Z pixel at the position of the G pixel in the Bayer array, the visible light signal of the G pixel, which is included in the same infrared light conversion block, can be interpolated during demosaicing. This simplifies the demosaicing process of the visible light signal.

[0193] <5. Fifth Embodiment>

[0194] In the fourth embodiment of this technology described above, the charge generated at the Z pixel is transferred and held by a pair of charge transfer units and charge holding units. Conversely, in the fifth embodiment of this technology, two pairs of charge transfer units and charge holding units are used. In this way, the accuracy of distance measurement can be improved.

[0195] [Pixel configuration]

[0196] Figure 20 This is a diagram illustrating an example of pixel configuration according to a fifth embodiment of the present technology. As... Figure 20 The Z pixel (Za) in the reference is pixel 140. Figure 4 The difference in the described Z-pixel 140 is that it also includes a charge transfer unit 144 and a charge retention unit 155. Please note that... Figure 20The other Z pixels (Zb, Zc, and Zd) in the reference are... Figure 4 The Z-pixels described differ in a similar way.

[0197] [Circuit structure of a pixel]

[0198] Figure 21 This is a diagram illustrating an example of pixel configuration in the fifth embodiment of the present technology. Figure 21 The circuit configuration of Z pixel 140, signal generation unit 150, and charge retention units 151 and 155 in the infrared light conversion block is shown.

[0199] Figure 21 Pixel 140 in the diagram does not necessarily include an overflow drain 143. Instead, a charge transfer unit 144 is further provided. Furthermore, signal line 101 includes TR5 instead of OFD4. Transmission 5 (TR5) is a signal line used to transmit control signals to the charge transfer unit 144. Figure 21 As shown, the anode of the photoelectric conversion unit 141 is grounded, and the cathode is connected to the source of charge transport units 142 and 144. The gates of charge transport units 142 and 144 are connected to TR4 and TR5, respectively. The drain of charge transport unit 142 is connected to a reference. Figure 3 The pixel 140 is connected to one end of the charge holding unit 151 in a similar manner. On the other hand, the drain of the charge transport unit 144 is connected to one end of the charge holding unit 155.

[0200] Signal generation unit 150 and reference Figure 3 The difference in the signal generation unit 150 described is that it also includes MOS transistors 156-158. For example... Figure 21 As shown, the drains of MOS transistors 156 and 157 are connected to Vdd. The source of MOS transistor 156 and the gate of MOS transistor 157 are connected to one end of the charge holding unit 155, to which the drain of the aforementioned charge transport unit 144 is connected. The other end of the charge holding unit 155 is grounded. The source of MOS transistor 157 is connected to the drain of MOS transistor 158, and the source of MOS transistor 158 is connected to signal line 102. Figure 21 As shown, signal line 102 consists of two signal lines and transmits signals output from MOS transistors 154 and 158, respectively. The gates of MOS transistors 156 and 158 are connected to signal lines RST and SEL, respectively.

[0201] MOS transistor 157 is a MOS transistor that generates a signal based on the charge held in charge holding unit 155. MOS transistor 158 is a MOS transistor that outputs the signal generated by MOS transistor 157 as an image signal to signal line 102. MOS transistor 156 is a MOS transistor that discharges the charge held in charge holding unit 155.

[0202] In this way, Figure 21 At pixel 140, the charge generated by the photoelectric conversion unit 141 can be separated and transferred to charge holding units 151 and 155. Since the composition of the other pixels is similar to that of the reference pixel... Figure 3 The composition of pixels, etc., will therefore be omitted from the description. Furthermore, as the ranging method in the fifth embodiment of this technology, a reference can be used. Figure 6 The ranging method described herein. Since the other components of the solid-state imaging device 20 and imaging system 1 are similar to those of the solid-state imaging device 20 and imaging system 1 in the first embodiment of this technology, their description will be omitted.

[0203] [Imaging Methods]

[0204] Figure 22 This is a diagram illustrating an imaging method according to a fifth embodiment of the present technology. Figure 22 It is shown in reference Figure 20 This explains the relationship between the input and output signals at pixel 140, etc.

[0205] First, an ON signal is input to RST, TR4, and TR5 (T1). In this way, the photoelectric conversion unit 141 is reset, and the charge held in the charge holding units 151 and 155 is discharged. After the reset is complete, the input of the ON signal to RST, TR4, and TR5 is stopped (T2).

[0206] Then, infrared light is emitted from the infrared light emitting unit 60, and an ON signal is input to TR4 (T3). In this way, the charge based on reflected infrared light generated by the photoelectric conversion unit 141 is retained in the charge holding unit 151.

[0207] Then, the infrared light emission of the infrared light emitting unit 60 is stopped, and the ON signal input to TR4 is stopped. At the same time, the ON signal is input to TR5 (T4). In this way, the charge based on reflected infrared light generated by the photoelectric conversion unit 141 is maintained in the charge holding unit 155.

[0208] Subsequently, the operations of T3 and T4 are repeated a predetermined number of times. In this way, charge based on reflected infrared light is accumulated in charge holding units 151 and 155.

[0209] Then, the ON signal is input to the SEL (T6). In this way, infrared light signals based on the charges held in the charge holding units 151 and 155 are output respectively. Then, the input of the ON signal to the SEL is stopped, and the ranging period ends (T7). The distance measuring unit 50 calculates the distance based on the output infrared light signals.

[0210] Please note that if the infrared light sensitivity is insufficient, infrared light signals can be generated at Zb, Zc, and Zd in a similar manner, and then added together for distance calculation.

[0211] In this way, the photoelectric conversion-based charge synchronized with the emitted infrared light is stored in the charge holding unit 151. On the other hand, the charge obtained as a result of photoelectric conversion occurring at a timing 180° phase offset relative to the emitted infrared light is stored in the charge holding unit 155. That is, using a single pixel, a reference can be performed. Figure 6 The first and second exposure periods are described. Therefore, compared to performing the first and second exposure periods using different pixels, the effects of sensitivity variations in photoelectric conversion can be reduced, thereby improving the accuracy of distance measurement. Furthermore, since all the charge generated by the photoelectric conversion unit 141 is transferred to the charge holding units 151 and 155, it is not necessary to provide an overflow drain at pixel 140.

[0212] In this way, according to the fifth embodiment of the present technology, two infrared light signals required for distance measurement can be generated using only one pixel. This reduces the influence of variations in sensitivity during photoelectric conversion, thereby improving the accuracy of distance measurement.

[0213] [Variation Example]

[0214] In the fifth embodiment of this technology described above, distance measurement is performed in a configuration where the charge transfer unit and charge retention unit of the Z pixel are added to the infrared light conversion block at the position of the G pixel in the Bayer array. Conversely, in the first embodiment of this technology, distance measurement can also be performed in a configuration where the charge transfer unit and charge retention unit are added to the Z pixel. Specifically, the charge transfer unit is added to a reference... Figure 4 The photoelectric conversion unit 121 of pixel 120 and the photoelectric conversion unit 141 of pixel 140 are described. Furthermore, a charge retention unit is added and connected to the charge retention unit thereon. In this way, the effects of sensitivity variations in photoelectric conversion can be reduced, thereby improving the accuracy of distance measurement when the infrared light conversion block consists of two infrared light conversion units and two visible light conversion units.

[0215] Furthermore, the above embodiments are examples embodying the present technology, and the matters in each embodiment correspond to the specific inventive matters in the claims. Similarly, the matters in embodiments denoted by the same names correspond to the specific inventive matters in the claims. However, the present technology is not limited to the embodiments, and various modifications of the embodiments can be embodied within the scope of the present technology without departing from its spirit.

[0216] Furthermore, the processing sequence described in the above embodiments can be treated as a method having a series of sequences, or as a recording medium for causing a computer to execute a series of programs and stored programs. As recording media, hard disks, CDs (compressed discs), MDs (MiniDiscs), DVDs (Digital Universal Discs), memory cards, and Blu-ray discs (registered trademarks) can be used.

[0217] The effects described in this specification are merely examples; these effects are not limited and other effects may exist.

[0218] Alternatively, this technology can also be configured as follows.

[0219] (1) A solid-state imaging device, comprising:

[0220] A visible light conversion block includes a visible light charge retention unit and a plurality of visible light conversion units. In each of the plurality of visible light conversion units, a light-receiving surface for receiving visible light is configured and constructed to generate a charge based on the amount of visible light received. The visible light charge retention unit is configured to exclusively retain the charges generated by the plurality of visible light conversion units respectively during different periods.

[0221] An infrared light conversion block includes an infrared light charge retention unit and a plurality of infrared light conversion units. Among the plurality of infrared light conversion units, the light receiving surface, which has a size substantially the same as that of the visible light conversion unit and is configured to receive infrared light, is configured to generate charge according to the amount of infrared light received. The infrared light charge retention unit is configured to collectively and simultaneously retain the charge generated by the plurality of infrared light conversion units respectively.

[0222] (2) The solid-state imaging device according to (1),

[0223] The visible light conversion block includes the visible light charge retention unit and four visible light conversion units.

[0224] (3) The solid-state imaging device according to (2),

[0225] The infrared light conversion block includes the infrared light charge retention unit and four infrared light conversion units.

[0226] (4) The solid-state imaging device according to (2),

[0227] The infrared light conversion block includes:

[0228] The two infrared light conversion units;

[0229] The two visible light conversion units; and

[0230] The infrared charge retention unit is configured to simultaneously and jointly retain the charges generated by the two infrared light conversion units while retaining the charges generated by the two infrared light conversion units, and to exclusively retain the charges generated by the two visible light conversion units at different times while retaining the charges generated by the two visible light conversion units.

[0231] (5) The solid-state imaging apparatus according to any one of (2) to (4),

[0232] The visible light conversion block includes the visible light charge retention unit and four visible light conversion units, wherein the red light conversion unit configured to generate charge based on red light, the green light conversion unit configured to generate charge based on green light, and the blue light conversion unit configured to generate charge based on blue light are arranged in the form of a Bayer array.

[0233] (6) The solid-state imaging apparatus according to any one of (2) to (4),

[0234] The visible light conversion block includes: a red light conversion unit configured to generate charge based on red light, a green light conversion unit configured to generate charge based on green light, a blue light conversion unit configured to generate charge based on blue light, a white light conversion unit configured to generate charge based on white light; and the visible light charge holding unit.

[0235] (7) The solid-state imaging apparatus according to any one of (1) to (6),

[0236] The infrared light conversion block further includes an infrared light charge transfer unit, which is configured to transfer the charge generated by the plurality of infrared light conversion units to the infrared light charge retention unit by simultaneously conducting electricity between the plurality of infrared light conversion units and the infrared light charge retention unit.

[0237] (8) The solid-state imaging apparatus according to any one of (1) to (7) further includes

[0238] An infrared light signal generation unit is configured to generate a signal based on the charge held in the infrared light charge holding unit.

[0239] (9) An imaging system comprising:

[0240] An infrared light emitting unit is configured to emit infrared light toward the subject being photographed;

[0241] A visible light conversion block includes a visible light charge retention unit and a plurality of visible light conversion units. In each of the plurality of visible light conversion units, a light-receiving surface for receiving visible light is configured and constructed to generate a charge based on the amount of visible light received. The visible light charge retention unit is configured to exclusively retain the charges generated by the plurality of visible light conversion units respectively during different periods.

[0242] An infrared light conversion block includes an infrared light charge retention unit and a plurality of infrared light conversion units. Among the plurality of infrared light conversion units, the light receiving surface having a size substantially the same as that of the visible light conversion unit and receiving infrared light emitted and reflected by the photographed object is configured and constructed to generate charge according to the amount of infrared light received. The infrared light charge retention unit is configured to collectively and simultaneously retain the charge generated by the plurality of infrared light conversion units respectively.

[0243] An infrared light signal generating unit is configured to generate a signal based on the charge held in the infrared light charge holding unit; and

[0244] A distance measuring unit is configured to measure the distance to the subject by measuring the time it takes for light to travel from emission at the infrared light emitting unit to reception at the infrared light conversion unit in the infrared light conversion block, based on the generated signal.

[0245] (10) A ranging method, comprising:

[0246] The steps for emitting infrared light towards the subject being photographed;

[0247] An infrared light signal generation step, which generates a signal based on the charge held in an infrared charge holding unit within an infrared light conversion block comprising multiple infrared light conversion units, wherein in the multiple infrared light conversion units, a light receiving surface having a size substantially the same as the size of the light receiving surface of the visible light conversion unit in the visible light conversion block, and receiving both emitted and reflected infrared light from the subject being photographed, is configured and constructed to generate a charge based on the amount of received infrared light; the infrared charge holding unit is configured to collectively and simultaneously hold the charges generated by the multiple infrared light conversion units respectively; the visible light conversion block includes a visible light charge holding unit and multiple visible light conversion units; in the multiple visible light conversion units, a light receiving surface for receiving visible light is configured and constructed to generate a charge based on the amount of received visible light; and the visible light charge holding unit is configured to exclusively hold the charges generated by the multiple visible light conversion units respectively during different periods; and

[0248] The ranging step involves measuring the distance to the subject by measuring the time from the emission of the infrared light to the reception of the light at the infrared light conversion unit in the infrared light block based on the generated signal.

[0249] List of reference numerals

[0250] 1 Imaging System

[0251] 10 Lenses

[0252] 20 Solid-state imaging devices

[0253] 30 Signal Processing Units

[0254] 40 Image Processing Units

[0255] 50 distance measurement units

[0256] 60 Infrared light emitting units

[0257] 100-pixel array unit

[0258] 110, 120, 130, 140, 160, 170, 180, 190 pixels

[0259] Photoelectric conversion units 111, 121, 131, 141, 161, 171, 181, 191

[0260] 112, 123, 132, 143 Overflow Drain

[0261] 113, 123, 133, 142, 144 Charge transport units

[0262] Color filters 119, 129, 139, 149

[0263] 150 signal generation units

[0264] 151, 155, 159 Charge retention units

[0265] 152-154, 156-158 MOS transistors

[0266] 200 vertical drive units

[0267] 300 horizontal transmission units

[0268] 400 Analog-to-Digital Converter

[0269] 610 Visible Light Conversion Block

[0270] 611 Visible Light Charge Holding Unit

[0271] 620, 620, 640, 650 Infrared light conversion blocks

[0272] 621, 631, 641, 651 Infrared photocharge retention units

Claims

1. A light detection device, comprising: The first pixel group includes a first floating diffusion region in a planar view and a first photoelectric conversion unit, a second photoelectric conversion unit, a third photoelectric conversion unit, and a fourth photoelectric conversion unit configured to detect visible light, wherein the first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit, and the fourth photoelectric conversion unit share the first floating diffusion region; and The second pixel group includes a second floating diffusion region in the planar view, and a fifth, sixth, seventh, and eighth photoelectric conversion unit configured to detect infrared light, wherein the fifth, sixth, seventh, and eighth photoelectric conversion units share the second floating diffusion region. In the plan view, the first floating diffusion region is arranged in the middle part of the first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit and the fourth photoelectric conversion unit, and in the cross-sectional view, it is arranged directly below the first dividing region, which is arranged between the first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit and the fourth photoelectric conversion unit.

2. The optical detection device according to claim 1, The first pixel group is adjacent to the second pixel group in the planar diagram.

3. The optical detection device according to claim 1, The first floating diffusion region is connected to the first transistor in the first signal generation unit of the first pixel group, and the second floating diffusion region is connected to the second transistor in the second signal generation unit of the second pixel group.

4. The optical detection device according to claim 3, The first transistor is different from the second transistor.

5. The optical detection device according to claim 1, It also includes: The third pixel group includes a third floating diffusion region in the planar view and a ninth, tenth, eleventh, and twelfth photoelectric conversion units configured to detect visible light, wherein the ninth, tenth, eleventh, and twelfth photoelectric conversion units share the third floating diffusion region.

6. The optical detection device according to claim 5, The third pixel group is adjacent to the first pixel group and the second pixel group in the plan view.

7. A light detection device, comprising: The first pixel group includes a first floating diffusion region and a first photoelectric conversion unit, a second photoelectric conversion unit, a third photoelectric conversion unit, and a fourth photoelectric conversion unit in a planar view. The first photoelectric conversion unit and the second photoelectric conversion unit are configured to detect visible light, and the third photoelectric conversion unit and the fourth photoelectric conversion unit are configured to detect infrared light. The first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit, and the fourth photoelectric conversion unit share the first floating diffusion region. and The second pixel group, as shown in the planar diagram, includes a second floating diffusion region and a fifth, sixth, seventh, and eighth photoelectric conversion unit. The fifth and sixth photoelectric conversion units are configured to detect visible light, while the seventh and eighth photoelectric conversion units are configured to detect infrared light. The fifth, sixth, seventh, and eighth photoelectric conversion units share the second floating diffusion region. In the plan view, the first floating diffusion region is arranged in the middle part of the first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit and the fourth photoelectric conversion unit, and in the cross-sectional view, it is arranged directly below the first dividing region, which is arranged between the first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit and the fourth photoelectric conversion unit.

8. The optical detection device according to claim 7, The first pixel group is adjacent to the second pixel group in the planar diagram.

9. The optical detection device according to claim 7, The first floating diffusion region is connected to the first transistor in the first signal generation unit of the first pixel group, and the second floating diffusion region is connected to the second transistor in the second signal generation unit of the second pixel group.

10. The optical detection device according to claim 9, The first transistor is different from the second transistor.

11. The optical detection device according to claim 7, It also includes: The third pixel group includes a third floating diffusion region in the planar view and a ninth, tenth, eleventh, and twelfth photoelectric conversion units configured to detect visible light, wherein the ninth, tenth, eleventh, and twelfth photoelectric conversion units share the third floating diffusion region.

12. The optical detection device according to claim 11, The third pixel group is adjacent to the first pixel group and the second pixel group in the plan view.

13. The optical detection device according to claim 7, The third photoelectric conversion unit and the fourth photoelectric conversion unit are located adjacent to the seventh photoelectric conversion unit and the eighth photoelectric conversion unit in the plan view.

Images