KR20130134739A - Three-dimensional image sensor - Google Patents

Abstract

A three-dimensional image sensor includes: a light source module which radiates transmission light to a subject; a lens module which includes a filter which includes received light reflected from the subject and a lens which collects light; a pixel circuit which generates and accumulates charges corresponding to the strength of the received light and outputs an analog signal by controlling conversion benefits about the accumulated charges; an analog digital conversion unit which provides a saturation determination signal for a control unit by determining whether the analog signal is saturated or not and converts the analog signal into a digital signal; and the control unit which provides a conversion benefit control signal for the pixel circuit by receiving the saturation determination signal from the analog digital conversion unit and transmits a control signal to the pixel circuit and the light source module.

Description

3-D Image Sensor {THREE-DIMENSIONAL IMAGE SENSOR}

The present invention relates to a three-dimensional image sensor, and more particularly to a three-dimensional image sensor for controlling the conversion gain to prevent saturation of the output voltage.

In a typical CMOS metal image sensor, a light receiving unit such as a photodiode or a photogate absorbs an optical signal to generate a charge, and a floating diffusion region of the generated charge. By accumulating in, a voltage having a magnitude corresponding to the absorbed optical signal is generated and an analog signal corresponding to the generated voltage is output.

Recently, three-dimensional image sensors (or depth sensors) for measuring a distance from a sensor to a subject using a CMOS image sensor have been studied. As a method of obtaining distance information from a sensor to a subject, a time of flight (TOF) method is widely used. The TOF method is a method of identifying the distance information from the sensor to the subject through the light travel time irradiated to the subject and reflected back.

In this TOF scheme, the intensity of the reflected light is inversely proportional to the square of the distance of the object and is proportional to the reflectance of the light source wavelength of the object. Therefore, when the conversion gain is fixed to a constant value, when the conversion gain set based on one object is low or high, the optical signal is too small for other objects, making accurate distance measurement difficult or the optical signal is too large, resulting in saturation of the output signal. (saturation), accurate distance measurement is impossible.

An object of the present invention is to provide an image sensor for measuring the accurate distance to the image by adjusting the conversion gain. It should be understood, however, that the present invention is not limited to the above-described embodiments, but may be variously modified without departing from the spirit and scope of the invention.

In order to achieve the object of the present invention, the three-dimensional image sensor according to the embodiments of the present invention includes a light source module for irradiating the transmission light to the subject, a filter for filtering the received light reflected from the subject and a lens for condensing A lens module that generates and accumulates charges corresponding to the intensity of the received light, and adjusts a conversion gain with respect to the accumulated charges and outputs them as analog signals; An analog-to-digital converter for converting the analog signal into a digital signal, and receiving the saturation determination signal from the analog-digital converter to provide a conversion gain adjustment signal to the pixel circuit, the pixel circuit and It may include a control unit for sending a control signal to the light source module.

In example embodiments, the controller may include a calculator configured to calculate a flight distance by measuring the intensity of the received light.

In example embodiments, the pixel circuit absorbs the received light to generate and accumulate a charge corresponding to the intensity of the received light, a transfer transistor to transfer the charge accumulated in the light receiver to a floating diffusion region, and the transfer A floating diffusion region for accumulating charge transferred through the transistor, a reset transistor for resetting the floating diffusion region for the next signal detection, a drive transistor for outputting and amplifying the charge accumulated in the floating diffusion region as the analog signal, and selection control A selection transistor for outputting the analog signal in accordance with an addressing order of a pixel array including the pixel circuit based on the signal, and a parallel connection with the floating diffusion region, based on the conversion gain adjustment signal received from the controller; The conversion gain It may include controlled by, the conversion gain control to prevent saturation of the analog signal for a flight distance measurement unit.

In example embodiments, the conversion gain control unit is connected in series with a conversion gain control transistor that operates based on the conversion gain control signal, and the conversion gain control transistor, and when the conversion gain control transistor is turned on, the fluting diffusion. And a capacitor connected in parallel with a parasitic capacitor in a region to adjust the conversion gain by adjusting the voltage of the fluting diffusion region.

According to an embodiment, the analog-to-digital converter compares the magnitude of the first analog signal with a saturation threshold, and if the magnitude of the analog signal is less than or equal to the saturation threshold, the saturation determination signal having a logic low level is determined. When the magnitude of the first analog signal is greater than the saturation threshold, the saturation determination signal having a logic high level may be provided to the controller.

According to an embodiment, when the magnitude of the first analog signal is greater than the saturation threshold, the first capacitor is turned on by receiving a logic high level first gain control signal from the controller and turning on the first gain control transistor. It is possible to prevent the saturation of the second analog signal by reducing the size of the second analog signal connected in parallel with the floating diffusion region and output through the drive transistor.

According to an embodiment, in the analog-to-digital converter, the magnitude of the second analog signal is compared with the saturation threshold value, and when the magnitude of the second analog signal is larger than the saturation threshold value, the second to Nth steps are sequentially performed. N is an integer greater than or equal to 2) As the gain control transistor is turned on, the second to Nth capacitors are connected in parallel with the floating diffusion region to reduce the size of the third to Nth analog signals output through the drive transistor, Saturation of the third to Nth analog signals can be prevented.

In example embodiments, the light receiving unit may be a photodiode and a photogate.

According to an embodiment, the filter may be an optical band pass filter.

In an embodiment, the lens module may further include a beam splitter having a coaxial structure that separates the received light into transmitted light and reflected light, and a light receiving unit that absorbs the reflected light from the beam splitter to generate a charge corresponding to the magnitude of the reflected light. It may include, and the intensity of the received light from the analog signal measured from the generated charge may be measured the flight distance.

The three-dimensional image sensor according to the embodiments of the present invention can prevent the output voltage of the pixel circuit from being saturated by adjusting the conversion gain, thereby making it possible to accurately measure the distance to the subject. However, the effects of the present invention are not limited thereto, and various modifications may be made without departing from the spirit and scope of the present invention.

1 is a block diagram illustrating a 3D image sensor according to an exemplary embodiment of the present invention.
FIG. 2 is a diagram illustrating an example in which a distance of a subject is calculated in the 3D image sensor of FIG. 1.
3 is a circuit diagram illustrating an example of a pixel circuit included in the 3D image sensor of FIG. 1.
FIG. 4 is a flowchart illustrating an example in which a conversion gain is adjusted in the 3D image sensor of FIG. 1.
5 is a block diagram illustrating a 3D image sensor according to another exemplary embodiment of the present invention.
6 is a block diagram illustrating an example of a computing system including a 3D image sensor according to example embodiments.

For the embodiments of the invention disclosed herein, specific structural and functional descriptions are set forth for the purpose of describing an embodiment of the invention only, and it is to be understood that the embodiments of the invention may be practiced in various forms, The present invention should not be construed as limited to the embodiments described in Figs.

As the inventive concept allows for various changes and numerous modifications, particular embodiments will be illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms may be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, the terms "comprise", "having", and the like are intended to specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be construed as meaning consistent with meaning in the context of the relevant art and are not to be construed as ideal or overly formal in meaning unless expressly defined in the present application .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same or similar reference numerals are used for the same components in the drawings.

1 is a block diagram illustrating a 3D image sensor according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the 3D image sensor 10 may include a detector 100, a controller 200, a light source module 300, and a lens module 400. The sensing unit 100 may include a pixel array 110, an analog-to-digital conversion (ADC) unit 120, and an image signal processor (ISP) 130.

The pixel array 110 may include a plurality of pixel circuits arranged in a matrix form. Each of the plurality of pixel circuits may detect the reception light RX to generate an analog signal having a magnitude corresponding to the intensity of the reception light RX, that is, the output voltage Vo. Each pixel circuit may include a plurality of transistors and capacitors to adjust the conversion gain to prevent saturation of the output voltage Vo. The pixel circuit 140 will be described later in more detail with reference to FIG. 3.

The ADC unit 120 may convert an analog signal received from a plurality of pixel circuits included in the pixel array 110 into a digital signal and output the digital signal. In addition, the saturation determination signal SAT may be generated and provided to the controller 200 by comparing the magnitude of the analog signal provided from the plurality of pixel circuits, that is, the output voltage Vo with the saturation threshold. For example, when the analog signal is greater than the saturation threshold, a saturation determination signal SAT of a logic high level is provided. When the analog signal is less than or equal to the saturation threshold, a floating diffusion region included in the pixel circuit is provided. The control unit 200 may provide a saturation determination signal SAT having a logic low level to the controller 200 by determining that it is not saturated.

The 3D image sensor 10 uses the digital signal provided from the ADC unit 120 to generate a depth map representing the distance information to the subject 50 by the 3D image sensor 10. The signal processor 130 may further include.

The controller 200 provides the transfer control signal TS, the reset control signal RS, the selection control signal SEL, and the conversion gain control signal CS to the plurality of pixel circuits included in the pixel array 110. The operation of the pixel array 110 may be controlled.

The calculator 210 included in the controller 200 may include a distance from the 3D image sensor 10 to the subject 50, a horizontal position of the subject 50, based on a digital signal provided from the ADC 120. The vertical position of the subject 50 and / or the area of the subject 50 may be calculated.

The light source module 300 may include a light source 310 and a lens 320. The light source 310 may output the light TX whose intensity is periodically changed by the controller 200. The light source 310 may be implemented as a light emitting diode (LED), a laser diode, or the like. The lens 320 may allow the light TX output from the light source to be focused on the subject 50.

The lens module 400 may include a filter 410 and a lens 420. The filter 410 is an optical bandpass filter that can pass light of a specific wavelength. For example, it may be an optical bandpass filter capable of passing only infrared rays and blocking light having a wavelength other than infrared rays. The lens 420 may perform a light condensing function.

As such, the 3D image sensor 10 determines whether the ADC unit 120 saturates the analog signal generated in each pixel circuit included in the pixel array 110, and transmits the saturation determination signal to the control unit 200. Accurate distance measurement is possible by preventing saturation of the output voltage Vo based on a feedback path that transmits and transmits a control signal to each pixel circuit based on the saturation determination signal SAT.

FIG. 2 is a diagram illustrating an example in which a distance of a subject is calculated in the 3D image sensor of FIG. 1.

1 and 2, the transmission light TX emitted from the light source module 300 may be reflected from the subject 50 and input to the lens module 400 as the reception light RX. The received light RX filtered and collected by the lens module 400 may be incident on the pixel array 110. The pixel array 110 may sample the received light RX periodically. According to an embodiment, the pixel array 110 includes two sampling points having a phase difference of 180 degrees for each period of the reception light RX (that is, a period of the transmission light TX), and four sampling points having a phase difference of 90 degrees each. The received light RX may be sampled at the sampling points or more sampling points. For example, the pixel array 110 may have samples A0, A1, A2, and A3 of the received light RX at phases of 90 degrees, 180 degrees, 270 degrees, and 360 degrees of the transmission light TX every cycle. Can be extracted. Receiving light (RX) is a phase difference Φ corresponding to twice the distance from the three-dimensional image sensor 10 to the subject 50 with respect to the transmission light TX can be calculated as shown in [Equation 1]. .

[Equation 1]

(Where A0, A1, A2, and A3 represent the intensity of received light sampled at phases of 90, 180, 270, and 360 degrees of TX, respectively).

The phase difference Φ of the reception light RX with respect to the transmission light TX corresponds to the time of flight (TOF) of the light. The distance from the three-dimensional image sensor 10 to the subject 50 is expressed by the formula " R = c * TOF / 2 " (where R denotes the distance of the subject 50 and c denotes the speed of light). Can be calculated. In addition, the distance from the 3D image sensor 10 to the subject 50 may be calculated using Equation 2 using the phase difference Φ of the received light RX.

&Quot; (2) "

(Where f represents the modulation frequency, i.e., the frequency of the received light RX)

Therefore, if the intensity of the transmission light RX can be sampled, the distance from the 3D image sensor 10 to the subject 50 can be obtained. The intensity of the transmission light RX can be measured by generating and accumulating a charge corresponding to the intensity of the transmission light RX, and obtaining an unsaturated analog signal, that is, an output voltage Vo from the accumulated charge.

Hereinafter, a pixel circuit capable of generating and accumulating charges corresponding to the intensity of the transmission light RX, and adjusting the conversion gain so as not to saturate the analog signal output from the accumulated charge, that is, the output voltage Vo, will be described. Let's explain.

3 is a circuit diagram illustrating an example of a pixel circuit included in the 3D image sensor of FIG. 1.

1 and 3, the pixel circuit 140 may include a light receiver 141, a signal generator 147, and a conversion gain adjuster 146.

The light receiving unit 141 may absorb the reception light RX and generate and accumulate charges corresponding to the intensity of the received reception light RX. In one embodiment, the light receiver 141 may include a photogate. In another embodiment, the light receiver 141 may include a photodiode.

The signal generator 147 may be connected between the light receiver 141 and the power supply voltage VDD. The signal generator 147 may include a transfer transistor 142, a reset transistor 143, a drive transistor 144, and a selection transistor 145. The transfer transistor 142 is connected between the light receiving unit 141 and the floating diffusion region FD, and transfers the charge generated by the light receiving unit 141 based on the transfer control signal TS received from the controller 200. (FD) can be sent. The reset transistor 143 is connected between the power supply voltage VDD and the floating diffusion region FD, and resets the floating diffusion region FD to detect the next signal in response to the reset control signal RS. In other words, the reset transistor 143 is turned on to discharge the charge stored in the floating diffusion region FD to the power supply voltage VDD, thereby resetting the floating diffusion region FD. The drive transistor 144 may be connected between the floating diffusion region FD and the power supply voltage VDD and may perform a source follower function for amplifying and outputting the charge accumulated in the floating diffusion region FD. . The selection transistor 145 may output an output according to the addressing order of the pixel array 110 based on the selection control signal SEL.

The conversion gain control unit 146 is connected to the floating diffusion region FD and performs a switch function based on the gain control signal CS received from the control unit 200. , CGN) and a capacitor C1... CN connected in series with the conversion gain adjusting transistors CG1,..., CGN. The conversion gain adjusting transistors CG1,..., CGN and the capacitors C1,..., CN may be paired in parallel and sequentially connected to the floating diffusion region FD.

Conversion gain refers to the ratio of the voltage of the floating diffusion region to the optical charge received by the light receiver 141. Since the floating diffusion region FD has parasitic capacitance, the magnitude of the voltage in the floating diffusion region FD may vary according to the size of the parasitic capacitance. Accordingly, the magnitude of the source followed output voltage Vo may also vary. Therefore, when the conversion gain control transistors CG1 to CGN are turned on, the parasitic capacitors and the capacitors C1 to CN of the floating diffusion region FD are connected in parallel to the floating diffusion region. In FD, since the equivalent capacitance becomes large, the voltage in the floating diffusion region FD becomes small, and accordingly, the magnitude of the output voltage Vo that is source-followed may also become small. Therefore, as the conversion gain adjusting transistors CG1, ..., CGN are additionally turned on and the capacitors C1, ..., CN are connected in parallel, the equivalent capacitance increases, and the source-followed output voltage Vo The size can be small. For example, when the parasitic capacitance of the floating diffusion region FD is Cp, the level of the gain control signal CS1 is converted to a logic high level in the conversion gain adjusting unit 146 and the conversion gain control transistor CG1 is turned on. In the floating diffusion region FD, the equivalent capacitance may be (Cp + C1). As a result, the magnitude of the voltage in the floating diffusion region FD can be reduced by the ratio of the voltage of the previous frame multiplied by Cp / (Cp + C1). Additionally, when the level of CS2 becomes the logic high level, the voltage magnitude in the floating diffusion region FD can be reduced by the ratio Cp / (Cp + C1 + C2). That is, as the capacitors C1,..., CN are additionally connected by the conversion gain control signal CS, the voltage magnitude in the floating diffusion region FD is reduced, so that the output voltage (output) output from the drive transistor 144 ( The size of Vo can be reduced. Accordingly, it can be made smaller than the threshold of the saturation voltage to prevent saturation, and accurate distance measurement can be possible. In one embodiment, if the output voltage Vo is less than or equal to the threshold of saturation, the conversion gain adjustment signal CS1,..., CSN is turned off in the conversion gain adjustment unit 146 to adjust the conversion gain. Transistors CG1,..., CGN are turned off, so that capacitors C1... CN may not be connected to floating diffusion region FD. Therefore, the conversion gain can be adjusted by the capacitors C1, ..., CN additionally connected.

The ADC unit 120 may generate the saturation determination signal SAT by comparing the magnitude of the output voltage Vo that is source-followed with a threshold value and provide the saturated determination signal SAT to the controller 200. For example, when the output voltage Vo is greater than the threshold value, the ADC unit 120 may provide a logic high level saturation determination signal SAT to the controller 200, and may be provided from the controller 200. When the gain control transistor CG1 is turned on based on the logical high level conversion gain control signal CS1, the capacitor is further connected to increase the equivalent capacitance of the fluting diffusion region FD, and thus the source followed. The magnitude of the voltage becomes small, so that saturation of the floating diffusion region FD can be prevented. On the other hand, when the output voltage Vo is less than or equal to the threshold, it is determined that the floating diffusion region FD included in the pixel circuit 140 is not saturated, and thus the saturation determination signal SAT having a logic low level is determined. It may be provided to the control unit 200, additionally the capacitors (C1, ..., CN) may not be connected. In other words, the conversion gain is adjusted to prevent saturation of the output voltage, and the intensity of the received light can be obtained, thereby making it possible to accurately measure the distance. In other words, the amount of charge accumulated in the floating diffusion region FD may be obtained by multiplying a voltage value in the floating diffusion region FD by an equivalent capacitance in the floating diffusion region FD, and the accumulated charge amount is absorbed by the light receiving unit 141. Since it corresponds to the intensity of the received light RX, the intensity of the received light RX can be obtained from the amount of charge in the floating diffusion region FD. If the intensity of the received light RX is known, the distance from the 3D image sensor 10 to the subject 50 may be obtained as described above.

FIG. 4 is a flowchart illustrating an example in which a conversion gain is adjusted in the 3D image sensor of FIG. 1.

1 to 3, when all of the conversion gain adjusting transistors CG1,..., CGN are turned off, the light source module 300 of the 3D image sensor 10 transmits the light to the subject 50. (TX) can be examined (Step S310). Thereafter, the received light RX reflected on the subject 50 may be filtered by the filter 410 and collected by the lens 420 (Step S320). The collected received light RX may be absorbed by the light receiver 141 to generate and accumulate charges corresponding to the intensity of the received light RX (Step S330). The accumulated charge is transferred to and accumulated in the floating diffusion region FD by the transfer transistor 142, and the voltage in the floating diffusion region FD is amplified by the drive transistor 144 to be output (Step S340). The amplified and output voltage Vo from the ADC unit 120 may be compared with a threshold of saturation (Step S350). In this case, when the output voltage Vo is less than or equal to the threshold value of saturation, the digital signal may be generated by digitally converting the output voltage Vo (Step S370). On the other hand, when the output voltage Vo is greater than the threshold of saturation, the saturation determination signal SAT is transmitted from the ADC unit 120 to the control unit 200, and the control gain control signal CS1,. CSN) becomes a logic high level, and the corresponding conversion gain adjusting transistors CG1, ..., CGN are turned on (Step S360), and the output smaller than the threshold of saturation as described above. The voltage Vo may be generated to prevent saturation. As described above, the 3D image sensor 10 may perform accurate distance measurement by preventing saturation through a feedback process from the ADC unit 120 to the control unit 200.

5 is a block diagram illustrating a 3D image sensor according to another exemplary embodiment of the present invention.

Referring to FIG. 5, in comparison with FIG. 1, the lens module 800 additionally includes a beam splitter 830 having a coaxial structure, and reflected light FX reflected at 90 degrees from the beam splitter 830. The light absorbing unit 840 may further include a light receiving unit 840 capable of absorbing and generating and accumulating charges corresponding to the intensity of the reflected reflected light FX. In one embodiment, the light receiver 840 may include a photogate. In another embodiment, the light receiver 840 may include a photodiode.

The light source module 700 may include a light source 710 and a lens 720. The light source 710 may be controlled by the controller 500 to output light TX whose intensity changes periodically. The light source 710 may be implemented as a light emitting diode (LED), a laser diode, or the like. The lens 720 may allow the light TX output from the light source to be focused on the subject.

The lens module 800 may include a filter 810 and a lens 820. The filter 810 may be an optical bandpass filter that may filter light having a wavelength other than infrared as an infrared filter. The lens 820 may perform a light condensing function. When the light collected from the lens 820 passes through the beam splitter 830, the light collected by the lens 820 may be separated into the transmitted light PX passing straight through and the reflected light FX reflected at 90 degrees. The transmitted light PX is absorbed into the pixel array 610. The reflected light RX is absorbed through the light receiving unit 840 included in the lens module 800, and generates and accumulates charges corresponding to the intensity of the reflected reflected light.

In one embodiment, the proportion of reflected light FX reflected from beam splitter 830 may be less than 4%. For example, when 2% is absorbed by the light receiver 840 by the beam splitter 830, the transmitted light PX is 98%. Therefore, the charge generated in the light receiver 840 corresponding to the reflected light FX is reflected in the pixel array 610. ) Will be much less quantitatively than the charge that is absorbed and accumulated. Therefore, when the analog signal output from the charge reflected from the beam splitter 830 and absorbed by the light receiver 840 is compared with the threshold of saturation, the possibility of saturation may be reduced. In other words, the beam splitter 830 may be added to measure the intensity of the received light RX even when the intensity of the received light RX is very strong.

6 is a block diagram illustrating an example of a computing system including a 3D image sensor according to example embodiments.

Referring to FIG. 6, the computing system 1000 includes a processor 1010, a memory device 1020, a storage device 1030, an input / output device 1040, a power supply 1050, and a three-dimensional image sensor 1060. can do. Although not shown in FIG. 6, the computing system 1000 may further include ports for communicating with a video card, a sound card, a memory card, a USB device, or the like, or with other electronic devices. have.

Processor 1010 may perform certain calculations or tasks. According to an embodiment, the processor 1010 may be a micro-processor, a central processing unit (CPU). The processor 1010 is capable of communicating with the memory device 1020, the storage device 1030, and the input / output device 1040 via an address bus, a control bus, and a data bus. have. In some embodiments, processor 1010 may be coupled to an expansion bus, such as a Peripheral Component Interconnect (PCI) bus. Memory device 1020 may store data necessary for operation of computing system 1000. For example, the memory device 1020 may be implemented as a volatile memory such as a dynamic random access memory (DRAM), a static random access memory (SRAM), a mobile DRAM, or the like, an electrically erasable programmable read-only memory (EEPROM) Flash Memory, PRAM (Phase Change Random Access Memory), RRAM, Nano Floating Gate Memory (NFGM), Polymer Random Access Memory (PoRAM), Magnetic Random Access Memory (MRAM), Ferroelectric Random Access Memory Random Access Memory (PRAM), Resistance Random Access Memory (RRAM), Nano Floating Gate Memory (NFGM), Polymer Random Access Memory (PoRAM), Magnetic Random Access Memory (MRAM), Ferroelectric Random Access Memory (FRAM) Or the like. Storage device 1030 may include a solid state drive, a hard disk drive, a CD-ROM, and the like. The input / output device 1040 may include input means such as a keyboard, a keypad, a mouse, and the like, and output means such as a printer or a display. Power supply 1050 can supply the operating voltage required for operation of computing system 1000.

The 3D image sensor 1060 may be connected to the processor 1010 through the buses or other communication links to perform communication. As described above, the 3D image sensor 1060 may provide distance information and color image information. The 3D image sensor 1060 may be implemented in various types of packages. For example, at least some components of the image sensor 1060 may be packaged on packages (PoPs), ball grid arrays (BGAs), chip scale packages (CSPs), plastic leaded chip carriers (PLCCs), plastic dual in-line packages. (PDIP), Die in Waffle Pack, Die in Wafer Form, Chip On Board (COB), Ceramic Dual In-Line Package (CERDIP), Plastic Metric Quad Flat Pack (MQFP), Thin Quad Flatpack (TQFP), Small Outline ( SOIC), Shrink Small Outline Package (SSOP), Thin Small Outline (TSOP), Thin Quad Flatpack (TQFP), System In Package (SIP), Multi Chip Package (MCP), Wafer-level Fabricated Package (WFP), Wafer- It can be implemented using packages such as Level Processed Stack Package (WSP).

Meanwhile, the computing system 1000 should be interpreted as any computing system that uses a three-dimensional image sensor. For example, the computing system 1000 may be a mobile phone, a smart phone, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital camera A personal computer (PC), a server computer, a workstation, a laptop, a digital television, a set-top box, a music player A music player, a portable game console, a navigation system, and the like.

The present invention can be applied to an image sensor and a system including the same. For example, the present invention provides a mobile phone, a smart phone, a personal digital assistant, a portable multimedia player, a digital camera, a computer, a laptop, a music player, a portable game console, a navigation system, a video phone, a surveillance system, an auto focus system, a tracking system, It may be usefully used for a motion detection system, an image stabilization system, a face recognition security system, and the like.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. You will understand.

10, 20: 3D image sensor 50, 51: subject
100, 600: detector 110, 610: pixel array
120, 620: ADC unit 130, 630: ISP unit
200, 500: control unit 210, 510: calculation unit
300, 700: light source module 310, 710: light source
320, 720: Lens 400, 800: Lens Module
410, 810: filter 420, 820: lens
830: beam splitter

Claims (10)

A light source module irradiating transmission light to a subject;
A lens module including a filter for filtering the received light reflected from the subject and a lens for condensing the light;
A pixel circuit which generates and accumulates charges corresponding to the intensity of the received light, and outputs an analog signal by adjusting a conversion gain with respect to the accumulated charges;
An analog-digital converter for determining whether the analog signal is saturated and providing a saturation determination signal to a controller, and converting the analog signal into a digital signal; And
And a controller which receives the saturation determination signal from the analog-digital converter, provides a conversion gain control signal to the pixel circuit, and sends a control signal to the pixel circuit and the light source module. The apparatus of claim 1, wherein the control unit
And a calculator configured to calculate a flight distance by measuring the intensity of the received light. 3. The pixel circuit of claim 2, wherein the pixel circuit is
A light receiving unit which absorbs the received light to generate and accumulate a charge corresponding to the intensity of the received light;
A transfer transistor configured to transfer charges accumulated in the light receiving unit to a floating diffusion region;
A floating diffusion region that accumulates charges transferred through the transfer transistor;
A reset transistor for resetting the floating diffusion region for next signal detection;
A drive transistor for outputting and amplifying the charge accumulated in the floating diffusion region as the analog signal;
A selection transistor configured to output the analog signal according to an addressing order of a pixel array including the pixel circuit based on a selection control signal; And
And a conversion gain control unit connected in parallel with the floating diffusion region and adjusting the conversion gain based on the conversion gain adjustment signal received from the control unit, thereby preventing saturation of the analog signal for flight distance measurement. Three-dimensional image sensor characterized by. The method of claim 3, wherein the conversion gain control unit
A conversion gain adjustment transistor operating based on the conversion gain adjustment signal; And
A capacitor connected in series with the conversion gain control transistor and connected to the parasitic capacitor of the fluting diffusion region when the conversion gain control transistor is turned on to adjust the voltage of the fluting diffusion region to adjust the conversion gain. Three-dimensional image sensor, characterized in that. 4. The method of claim 3, wherein the analog-digital converter compares the magnitude of the first analog signal with a saturation threshold, and when the magnitude of the analog signal is less than or equal to the saturation threshold, the saturation determination signal having a logic low level. And providing a logic high level saturation determination signal to the controller when the magnitude of the first analog signal is greater than the saturation threshold. 6. The method of claim 5, wherein when the magnitude of the first analog signal is greater than the saturation threshold value, the first capacitor is turned on by receiving a logic high level first gain control signal from the controller and turning on the first gain control transistor. And a second analog signal outputted through the drive transistor in parallel with the floating diffusion region to reduce saturation of the second analog signal. The method of claim 6, wherein the analog-to-digital converter compares the magnitude of the second analog signal with a saturation threshold, and sequentially increases the second to Nth values when the magnitude of the second analog signal is greater than the saturation threshold. N is an integer greater than or equal to 2) As the gain control transistor is turned on, the second to Nth capacitors are connected in parallel with the floating diffusion region to reduce the size of the third to Nth analog signals output through the drive transistor, 3D image sensor, characterized in that to prevent saturation of the third to Nth analog signal. The 3D image sensor of claim 3, wherein the light receiving unit is a photodiode and a photogate. 4. The three-dimensional image sensor of claim 3, wherein the filter is an optical band pass filter. The method of claim 3, wherein
The lens module further includes a beam splitter having a coaxial structure that separates the received light into transmitted light and reflected light, and a light receiving unit that absorbs the reflected light from the beam splitter to generate a charge corresponding to the size of the reflected light,
And the flight distance is measured by measuring the intensity of the received light from the analog signal measured from the generated charge.

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