CN109817655A

CN109817655A - Pixel unit, image sensor chip, imaging system, forming method with double charge storage organization and the method that fathoms

Info

Publication number: CN109817655A
Application number: CN201910147658.8A
Authority: CN
Inventors: 徐渊; 陈志勇; 陈享; 黄志宇
Original assignee: Shenzhen City Light Micro Technology Co Ltd
Current assignee: Shenzhen City Light Micro Technology Co Ltd
Priority date: 2018-11-14
Filing date: 2019-02-27
Publication date: 2019-05-28

Abstract

The application provides the pixel unit with double charge storage organization, the image sensor chip with double charge storage organization, imaging system, the forming method of pixel unit with double charge storage organization, depth information measuring method and imaging system measurement picture depth method, and pixel unit includes: substrate；Photodiode；First voltage signal output module, output voltage signal when receiving control signal；Second voltage signal output module, the output voltage signal when receiving control signal；Wherein, be arranged be sent to first switch control signal it is identical as the phase of modulation light, the phase complements that the control signal for being sent to second switch is set and is sent to modulation light, the voltage signal that first voltage signal output module and the output of second voltage signal output module under out of phase are obtained after receiving reflected light, is calculated the flight time of modulation light.The application is able to ascend the reaction speed of pixel unit, and can measure different distances, and measurement accuracy is also relatively high.

Description

Pixel unit, image sensor chip, imaging system with double charge storage organization System, forming method and the method that fathoms

Technical field

This application involves field of image processings, more particularly to the pixel unit with double charge storage organization, have double electricity The image sensor chip of lotus storage organization, imaging system, forming method, the depth of pixel unit with double charge storage organization It spends information measuring method and imaging system measures picture depth method.

Background technique

Compared with ccd image sensor, cmos image sensor has the advantages that low-power consumption, low cost and high integration, And since its manufacturing process is compatible with standard CMOS process, cmos image sensor is rapidly developed, and has become research Hot spot.

Referring to Fig. 1, traditional 4T-PPD mainly by clamper photodiode PPD, transfer tube TG, floating diffusion region FD, Source follower SF, gate tube SEL and reset transistor RST are constituted.The brief working principle of 4T-PPD pixel is as follows:

Firstly, pixel unit is during resetting, while opening reset transistor RST and transfer tube TG, so that N buried layer internal electron It is depleted, at this moment N buried layer will be in empty trap state, and floating diffusion region FD will also be in high potential.Floating diffusion node at this time Current potential by source follower SF, gate tube SEL, first signal as correlated-double-sampling CDS is output to bus.Its Secondary, after the time for exposure completes exposure, second of unlatching transfer tube TG makes the suspension for being gathered in clamper photodiode PPD Charge below inversion layer is transferred to N-type floating diffusion region (FD), and is maintained at floating diffusion region FD after transfer tube TG closing On, form voltage VFD.Voltage VFD is used as correlation is double to adopt by source follower (SF) output voltage, selected siphunculus (SEL) control Second signal of sample (CDS) is transferred to bus.Finally, the input signal of two correlated-double-samplings (CDS) is done by subsequent conditioning circuit Difference obtains the analogue value for characterizing corresponding optical signal, subsequent ADC is transferred to be converted into digital quantity, needed for obtaining after processing The image wanted.

It is used for ranging using traditional 4T-PPD pixel unit of single floating diffusion region (FD) shown in FIG. 1, there is reaction The problem of speed is slow and can only survey long range, while measure when, also needs the photodetector and high-precision meter of high speed When circuit, be otherwise difficult to obtain high accuracy depth information, and in some high-precision safety detections and industrial control field, Quick and high-precision distance measuring method is very important, can not thus be suitable for safety detection and industrial control field these The requirement of high-precision industry.

Summary of the invention

The application provides a kind of pixel unit with double charge storage organization, the image with double charge storage organization passes Sensor chip, imaging system, the forming method of pixel unit with double charge storage organization, depth information measuring method and Imaging system measures picture depth method, can be had when solving measurement image depth information now using 4 traditional transistors There are reaction speeds for active picture sensor slowly, can only measure over long distances and be unable to satisfy safety detection and and industrial control field The problem of requirement of these high-precision industries.

According to a first aspect of the present application, the application provides a kind of pixel unit with double charge storage organization, pixel Unit includes: substrate；Photodiode is set in substrate, in response to incident reflection on the photodiode Light and stored charge；First voltage signal output module, be used to accumulate photodiode charge conversion be voltage letter Number comprising first switch, the control terminal of first switch receive control signal, and the input terminal of first switch connects two pole of photoelectricity The output end of pipe, first switch exports first voltage signal when the control terminal of first switch receives control signal；And the Two voltage signal output modules, be used to accumulate photodiode charge conversion be voltage signal comprising second opens It closes, the control terminal of second switch receives control signal, and the input terminal of second switch connects photodiode, the output of second switch It holds and exports second voltage signal when the control terminal of second switch receives control signal；Wherein, setting is sent to first switch Control signal it is identical as the phase of modulation light, setting, which is sent to, the control signal of second switch and is sent to the control of first switch The phase complements of signal processed, transmitting modulation light to object under test, when being measured using two tap two phase methods, pixel unit Receive object under test receive modulation light back reflection return reflected light after, obtain first voltage signaling module output voltage The first voltage signal PS0 of the first voltage signal output module for being reflected light when phase is 0 ° output, obtains second voltage The voltage signal of signaling module output is the second of second voltage signal output module output of the reflected light when phase is 180 ° Voltage signal PS1；According to formula:The flight time of modulation light is calculated, wherein T_onFor modulation Level is the high time to light in one cycle.

Preferably, when being measured using two taps, four phase method, the photodiode of pixel unit receives again After reflected light, the voltage for obtaining the output of first voltage signaling module is that first voltage signal of the reflected light when phase is 90 ° is defeated The first voltage signal PS2 of module output out, the voltage for obtaining the output of second voltage signaling module exist for the reflected light of modulation light The second voltage signal PS3 of second voltage signal output module output when phase is 270 °；According to formula:The flight time of modulation light is calculated, wherein T_tofFor modulating light two-way time, T_pluseFor the period of modulated optical signal.

Preferably, photodiode is set to the center of substrate, the first switch of first voltage signal output module For the first transmission transistor, the first transmission transistor is set in substrate and is set to the side of photodiode, and first passes Defeated transistor and photodiode-couple are exported with the charge for accumulating photodiode as voltage signal, and second voltage signal is defeated The second switch of module is the second transmission transistor out, and the second transmission transistor is set in substrate and symmetrical first transmission is brilliant Body pipe is set to the other side of photodiode, and the second transmission transistor and photodiode-couple are to accumulate photodiode Charge output be voltage signal；First voltage signal output module further include: the first floating diffusion region is set in substrate And it is set to side of first transmission transistor far from photodiode, wherein the first transmission transistor is by photodiode The electric charge transfer of accumulation is saved to the first floating diffusion region；First reset transistor is set in substrate and couples photoelectricity Diode, the charge to save the first floating diffusion region reset；First source following transistor, control terminal connection First floating diffusion region, input terminal connect the first reset transistor；And first gating transistor, input terminal connection first The output end of source following transistor, the output end output voltage signal of the first gating transistor；Second voltage signal exports mould Block further include: the second floating diffusion region is set in substrate and is set to the second transmission transistor far from photodiode Side, wherein the second transmission transistor by the second voltage signal of photodiode be transferred to the second floating diffusion region carry out It saves；Second reset transistor, is set on substrate and couples photodiode, to the electricity for saving the second floating diffusion region Lotus is resetted；Second source following transistor, control terminal connect the second floating diffusion region, and input terminal connection second resets Transistor；And second gating transistor, input terminal connect the output end of the second source following transistor, the second gating crystal The output end output voltage signal of pipe.

Preferably, pixel unit further includes deep trench isolation structure, is used to be isolated the active area of adjacent pixel unit Domain, the periphery around pixel unit are set in substrate.

Preferably, pixel unit further includes barn door, is used to that light to be stopped to be irradiated to other than photodiode On region and electrical interference is shielded, is set to the upper of first voltage signal output module and second voltage signal output module Surface.

Preferably, pixel unit further includes lenticule, is used to for light-ray condensing being irradiated to the photosensitive area of photodiode On domain, it is set to the upper surface of pixel unit.

According to a second aspect of the present application, the application provides a kind of imaging sensor core with double charge storage organization Piece, image sensor chip include: pixel array comprising multiple pixel units as claimed in claim 1, or, comprising: lining Bottom；Multiple photodiodes, photodiode are set in substrate, in response to incident reflection on the photodiode Light and stored charge, first voltage signal output module, the charge conversion for being used to accumulate in photodiode is voltage letter Number comprising first switch, the control terminal of first switch receive control signal, and the input terminal of first switch connects two pole of photoelectricity The output end of pipe, first switch exports first voltage signal when the control terminal of first switch receives control signal；And the Two voltage signal output modules, be used to accumulate photodiode charge conversion be voltage signal comprising second opens It closes, the control terminal of second switch receives control signal, and the input terminal of second switch connects photodiode, the output of second switch It holds and exports second voltage signal when the control terminal of second switch receives control signal, wherein photodiode forms array, Photodiode shares first voltage signal output module and second voltage signal output module；Pixel drive unit is used Pixel unit work in output control signal control pixel array, connects pixel array；Sensing element is used to read And the voltage signal of the pixel unit output in output pixel array, connect pixel array；Control unit is connected and is controlled Pixel array, pixel drive unit and sensing element；Wherein, system opens modulation photo-emission source and sends modulation light, and control is single The control signal that member control pixel drive unit is sent to first switch is identical as the phase of modulation light, is sent to second switch The phase complements of control signal and the control signal for being sent to first switch, emitting the time span through ovennodulation every time is T_pulse Modulation light pulse, when using two tap two phase methods measure when, pixel unit receives object under test and receives tune After the reflected light that light back reflection processed is returned, the voltage for obtaining the output of first voltage signaling module is reflected light when phase is 0 ° The first voltage signal PS0 of first voltage signal output module output, obtains the voltage signal of second voltage signaling module output The second voltage signal PS1 of the second voltage signal output module for being reflected light when phase is 180 ° output；According to formula:The flight time of modulation light is calculated, wherein T_onFor modulation light, level is high in one cycle Time.

According to the third aspect of the application, the application provides a kind of imaging system comprising image sensing as described above Chip and laser emitter.

According to the fourth aspect of the application, the application provides a kind of formation of pixel unit with double charge storage organization Method, a kind of forming method of pixel unit, method include: setting substrate；Photodiode is set, is set in substrate, It is to the stored charge in response to incident reflected light on the photodiode；First voltage signal output module is set, For will accumulate photodiode charge conversion be voltage signal comprising first switch, first switch control termination Receive control signal, the input terminal of first switch connects photodiode, the control terminal of the output end of first switch in first switch First voltage signal is exported when receiving control signal；And setting second voltage signal output module, it is used to accumulate The charge conversion of photodiode is voltage signal comprising second switch, the control terminal of second switch receive control signal, the The input terminal of two switches connects photodiode, and the output end of second switch receives control signal in the control terminal of second switch When export second voltage signal；Wherein, setting be sent to first switch control signal it is identical as the phase of modulation light, setting send out The phase complements of the control signal and the control signal for being sent to first switch of second switch are sent to, emits modulation light, works as use When two tap two phase methods measure, pixel unit receives object under test and receives the reflected light that modulation light back reflection is returned Afterwards, the voltage for obtaining the output of first voltage signaling module is first voltage signal output mould of the reflected light when phase is 0 ° The first voltage signal PS0 of block output, the voltage signal for obtaining the output of second voltage signaling module is that reflected light is in phase The second voltage signal PS1 of second voltage signal output module output at 180 °；According to formula: The flight time of modulation light is calculated, wherein T_onFor modulation light, level is the high time in one cycle.

According to the 5th of the application the aspect, the application provides a kind of depth information measuring method, a kind of depth information measuring and calculating Method, method include: setting pixel array comprising multiple pixel units as claimed in claim 1, or, comprising: substrate；It is more A photodiode, photodiode are set in substrate, in response to incident reflected light on the photodiode Stored charge, first voltage signal output module, be used to accumulate photodiode charge conversion be voltage signal, Including first switch, the control terminal of first switch, which receives, controls signal, the input terminal connection photodiode of first switch, and first The output end of switch exports first voltage signal when the control terminal of first switch receives control signal；And second voltage letter Number output module, the charge conversion for being used to accumulate in photodiode is voltage signal comprising second switch, second opens The control terminal of pass receives control signal, and the input terminal of second switch connects photodiode, and the output end of second switch is second The control terminal of switch exports second voltage signal when receiving control signal, wherein photodiode forms array, two pole of photoelectricity It manages and shares first voltage signal output module and second voltage signal output module；Pixel drive unit is set, is used for defeated Pixel unit work in control signal control pixel array out, connects pixel array；Sensing element is set, is used to read And the voltage signal of the pixel unit output in output pixel array, connect pixel array；Control unit is set, and connection is simultaneously Control pixel array, pixel drive unit and sensing element；Wherein, system opens modulation photo-emission source and sends modulation light, control The control signal that unit control pixel drive unit processed is sent to first switch is identical as the phase of modulation light, is sent to second and opens The phase complements of the control signal of pass and the control signal for being sent to first switch, emitting the time span through ovennodulation every time is T_pulseModulation light pulse, control unit control pixel drive unit exports to the first of first voltage signal output module and opens The control signal of pass is identical as the phase of laser pulse, and control pixel drive unit is exported to second voltage signal output module The phase complements of the control signal and laser pulse of second switch, when being measured using two tap two phase methods, pixel list Member receive object under test receive modulation light back reflection return reflected light after, obtain first voltage signaling module output electricity Pressure be the first voltage signal PS0 of first voltage signal output module output of the reflected light when phase is 0 °, acquisition the The voltage signal of two voltage signal modules output is second voltage signal output module output of the reflected light when phase is 180 ° Second voltage signal PS1；According to formula:The flight time of modulation light is calculated, In, T_tofFor modulating light two-way time, T_pluseFor the period of modulated optical signal.

According to the 5th of the application the aspect, the application provides a kind of imaging system measurement picture depth method, comprising: configuration The command parameter of imaging system；Start imaging system；According to the command parameter of configuration, depth information is calculated as described above The image depth information of method measuring targets measures；Believed according to the image grayscale of the command parameter measuring targets of configuration Breath measures；Image depth values and gray value of image that measurement obtains are obtained, and are calculated.

The beneficial effects of the present application are as follows: the application exports mould by the way that first voltage signal is arranged in pixel cell structure Block and second voltage signal output module, first voltage signal output module and second voltage signal output module are receiving Photodiode can be responded to the charge conversion that reflected light is accumulated for voltage signal after controlling signal, then pass through the first electricity of setting Press the phase between the first switch of signal output module and the second switch of second voltage signal output module with modulation light Relationship obtains first voltage signal output module and second voltage signal under out of phase and exports mould after receiving reflected light The voltage signal of block output, can be calculated the flight time of modulation light, and this makes it possible to the reaction speed for promoting pixel unit Degree, and can measure different distances, and measurement accuracy is also relatively high, meet safety detection and with industrial control field these The requirement of high-precision industry, so that application range of products is more extensive.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of traditional 4 transistor active element sensors；

Fig. 2 is the structural schematic diagram of the pixel unit in the application first embodiment with double charge storage organization；

Fig. 3 is the structural schematic diagram of the pixel unit in the application second embodiment with double charge storage organization；

Fig. 4 is the equivalent circuit schematic of Fig. 3；

Fig. 5 is the schematic top plan view of the structure of pixel unit in the application second embodiment；

Fig. 6 is another structural schematic diagram of pixel unit in the application second embodiment；

Fig. 7 is the schematic diagram of the image sensor chip in the application 3rd embodiment with double charge storage organization；

Fig. 8 is the flow chart that the application the 7th implements the depth information measuring method exemplified.

Description of symbols: the transmission of 203 photodiode PPD first voltage signal output module 201 first of substrate is brilliant The first floating diffusion region body pipe TG1 FD1 the first reset transistor the first source following transistor of RST1 SF1 first gates crystalline substance 202 second the second floating diffusion region transmission transistor TG2 FD2 second of body pipe SEL1 second voltage signal output module resets 301 second N-type of transistor RST2 the second source following transistor SF2 the second gating transistor the first N-type ion of SEL2 area 302 third N-type ion area 303 304 N-type buried layer of the 4th N-type ion area of ion area, 305 deep trench isolation structure 306 hides 402 sensing element of tabula rasa 307 lenticule, 308 pixel array, 401 pixel drive unit, 403 control unit 404.

Specific embodiment

The application is described in further detail below by specific embodiment combination attached drawing.

The design of the application is: can measure environment light and measurement quilt by being arranged in the structure of traditional 4T-APS The pixel cell structure for surveying object reflected light is able to ascend the accuracy of measurement image depth information, so that product uses model It encloses wider.

Embodiment one:

Referring to Fig. 2, the pixel unit with double charge storage organization includes: substrate 203, photodiode PPD, first Voltage signal output module 201 and second voltage signal output module 202.

Photodiode PPD is set in substrate 203, to anti-on photodiode PPD in response to being incident on Penetrate light and stored charge；First voltage signal output module 201 is used to that the charge conversion in photodiode PPD will to be accumulated For voltage signal comprising first switch, the control terminal of first switch receive control signal, and the input terminal of first switch connects light Electric diode PPD, the output end of first switch output first voltage letter when the control terminal of first switch receives control signal Number；Second voltage signal output module 202, be used to accumulate photodiode PPD charge conversion be voltage signal, Including second switch, the control terminal of second switch receives control signal, and the input terminal of second switch connects photodiode PPD, The output end of second switch exports second voltage signal when the control terminal of second switch receives control signal.

Substrate 203 is used to form device architecture or chip circuit, and substrate 203 can be semiconductor base, semiconductor base Including silicon substrate 203, silicon-Germanium substrate 203, silicon carbide substrates 203, silicon-on-insulator (SOI) substrate 203, germanium on insulator (GOI) substrate 203, glass substrate 203 or III-V compound substrate 203 (such as silicon nitride or GaAs etc.).Substrate 203 It may be body substrate, i.e. silicon substrate 203, silicon-Germanium substrate 203 or silicon carbide substrates 203.In other embodiments, substrate 203 It can also be silicon-on-insulator substrate 203 or germanium substrate on insulator 203.In other embodiments, substrate 203 can also include Semiconductor base and the epitaxial layer that semiconductor substrate surface is formed in by epitaxy technique.

In the present embodiment, substrate 203 includes: outside p-type single crystalline silicon substrate 203 (p-type substrate) and p-type Prolong layer (p-epitaxial layer).

Photodiode PPD is set in substrate 203, and photodiode PPD is formed by ion implantation technology, moreover, By controlling the energy and concentration of ion implanting, the depth and injection range of ion implanting can be controlled, to control photoelectricity two The depth and thickness of pole pipe PPD.

In the present embodiment, photodiode PPD is clamper photodiode (Pinned Photodiode, PPD).Photoelectricity Doped with N-type ion in diode PPD, N-type ion includes phosphonium ion, arsenic ion or antimony ion.In addition, photodiode PPD Relative to conventional photodiode surface layer more than a thin layer of P+ layer, by the top P+ layers of N buried layer by charge collection layer Keep apart with Si/SiO2 top surface, mask the trap for causing dark current main cause, so that clamper photodiode PPD On the one hand relatively traditional photodiode has smaller dark current, is on the other hand capable of forming complete depletion of accumulation region, The problem of overcoming output picture lag.

Photodiode PPD is set to the center of substrate 203, and the first of first voltage signal output module 201 opens It closes and is set in substrate 203 for the first transmission transistor TG1, the first transmission transistor TG1 and is set to photodiode PPD Side, the first transmission transistor TG1 coupled with photodiode PPD with photodiode PPD is accumulated charge output is Voltage signal, the second switch of second voltage signal output module 202 are the second transmission transistor TG2, the second transmission transistor TG2 is set in substrate 203 and symmetrical first transmission transistor TG1 is set to the other side of photodiode PPD, and second passes Defeated transistor TG2 is coupled with photodiode PPD to be exported with the charge for accumulating photodiode PPD as voltage signal.

It is illustrated below with reference to working principle of the Fig. 2 to the present embodiment.

Wherein, when being measured using two tap two phase methods, it is only necessary to primary integral, specifically, pixel list Member receive object under test receive modulation light back reflection return reflected light after, obtain first voltage signal output module 201 The voltage of output is the first voltage signal PS0 that first voltage signal output module 201 of the reflected light when phase is 0 ° exports, Obtaining the voltage signal that second voltage signal output module 202 exports is second voltage signal of the reflected light when phase is 180 ° The second voltage signal PS1 that output module 202 exports；According to formula:When the flight of modulation light is calculated Between, wherein T_onIt is modulation light in a cycle T_pluseInterior level is the high time.

Further according to formula:The image depth information of object under test is calculated_Depth。

Further, it when measuring using two taps, four phase method, needs to be integrated twice, specifically, first Integration phase, the photodiode PPD of pixel unit receive object under test and receive the reflected light that modulation light back reflection is returned Afterwards, obtaining the voltage that first voltage signal output module 201 exports is first voltage letter of the reflected light when phase is 0 ° The first voltage signal PS0 of number output module output, it is anti-for obtaining the voltage signal that second voltage signal output module 202 exports Penetrate the second voltage signal PS1 of second voltage signal output module output of the light when phase is 180 °；The second integral stage, as After plain unit receives reflected light again, obtaining the voltage that first voltage signal output module 201 exports is reflected light in phase First voltage signal PS2 when being 90 ° obtains the reflection that the voltage that second voltage signal output module 202 exports is modulation light Second voltage signal PS3 of the light when phase is 270 °；

According to formula:The flight time of modulation light is calculated, wherein T_tofTo adjust Frequency light two-way time, T_pluseFor the period of modulated optical signal.

Further according to formula:The image depth information Depth of object under test is calculated.

Embodiment two:

Fig. 3 and Fig. 4 are please referred to, the pixel unit with double charge storage organization includes: substrate 203, photodiode PPD, first voltage signal output module 201 and second voltage signal output module 202.

Substrate 203 is used to form device architecture or chip circuit, and substrate 203 can be semiconductor base, semiconductor base Including silicon substrate, silicon-Germanium substrate, silicon carbide substrates, silicon-on-insulator (SOI) substrate, germanium on insulator (GOI) substrate, glass lined Bottom or III-V compound substrate (such as silicon nitride or GaAs etc.).Substrate 203 or body substrate, i.e. silicon substrate, silicon Germanium substrate or silicon carbide substrates.In other embodiments, substrate 203 can also serve as a contrast for silicon-on-insulator substrate or germanium on insulator Bottom.In other embodiments, substrate 203 can also include semiconductor base and be formed in semiconductor base by epitaxy technique The epitaxial layer on surface.In the present embodiment, substrate 203 includes: p-type single crystalline silicon substrate (p-type substrate) and p-type Epitaxial layer (p-epitaxial layer).

Photodiode PPD is set in substrate 203, and photodiode PPD is formed by ion implantation technology, moreover, By controlling the energy and concentration of ion implanting, the depth and injection range of ion implanting can be controlled, to control photoelectricity two The depth and thickness of pole pipe PPD.In the present embodiment, photodiode PPD is clamper photodiode (Pinned Photodiode, PPD).Doped with N-type ion in photodiode PPD, N-type ion include phosphonium ion, arsenic ion or antimony from Son.In addition, photodiode PPD relative to conventional photodiode surface layer more than a thin layer of P+ layer, pass through top P+ Layer keeps apart the N buried layer of charge collection layer with Si/SiO2 top surface, masks the trap for causing dark current main cause, So that on the one hand relatively traditional photodiode has smaller dark current for clamper photodiode, on the other hand it is capable of forming Complete depletion of accumulation region overcomes the problem of exporting picture lag.

Please continue to refer to Fig. 3 and Fig. 4, first voltage signal output module 201 includes: the first transmission transistor TG1, first Floating diffusion region FD1, the first reset transistor RST1, the first source following transistor SF1 and the first gating transistor SEL1.

First transmission transistor TG1, is set in substrate 203 and is set to the side of photodiode PPD, and first Transmission transistor TG1 is coupled with photodiode PPD and is exported with the charge for accumulating photodiode PPD as voltage signal；The One floating diffusion region FD1 is set in substrate 203 and is set to the first transmission transistor TG1 far from photodiode PPD Side, wherein the electric charge transfer that the first transmission transistor TG1 accumulates photodiode PPD to the first floating diffusion region FD1 It is saved；First reset transistor RST1 is set in substrate 203 and couples photodiode PPD, first to float The charge that diffusion region FD1 is saved is resetted；First source following transistor SF1, control terminal connect the first floating diffusion region FD1, input terminal connect the first reset transistor RST1；And the first gating transistor SEL1, input terminal connect the first source Pole follows the output end of transistor SF1, the output end output voltage signal of the first gating transistor SEL1.

In the present embodiment, the first transmission transistor TG1, the first reset transistor RST1, the first source following transistor SF1 And first gating transistor SEL1 be metal-oxide-semiconductor.

Second voltage signal output module 202 includes: the second transmission transistor TG2, the second floating diffusion region FD2, second Reset transistor RST2, the second source following transistor SF2 and the second gating transistor SEL2.

Second transmission transistor TG2 is set in substrate 203 and symmetrical first transmission transistor TG1 is set to photoelectricity two The other side of pole pipe PPD, the electricity that the second transmission transistor TG2 is coupled with photodiode PPD to accumulate photodiode PPD Lotus output is voltage signal；Second floating diffusion region FD2 is set in substrate 203 and is set to the second transmission transistor Side of the TG2 far from photodiode PPD, wherein the second transmission transistor TG2 believes the second voltage of photodiode PPD Number being transferred to the second floating diffusion region FD2 is saved；Second reset transistor RST2 is set on substrate 203 and couples light Electric diode PPD, the charge to save the second floating diffusion region FD2 reset；Second source following transistor SF2, Its control terminal connects the second floating diffusion region FD2, and input terminal connects the second reset transistor RST2；Second gating transistor SEL2, input terminal connect the output end of the second source following transistor SF2, the output end output of the second gating transistor SEL2 Voltage signal.

In the present embodiment, the second transmission transistor TG2, the second reset transistor RST2, the second source following transistor SF2 And second gating transistor SEL2 be metal-oxide-semiconductor.

Referring to Fig. 5, Fig. 5 is the structure top view of pixel unit.Photodiode PPD is square and is set to substrate 203 center.First transmission transistor TG1 is set to the side of photodiode PPD, the first floating diffusion region FD1, One reset transistor RST1, the first source following transistor SF1 and the first gating transistor SEL1 are set to the first transmission crystalline substance Side of the body pipe TG1 far from photodiode PPD, the symmetrical first transmission transistor TG1 of the second transmission transistor TG2 are set to light The other side of electric diode PPD, the second floating diffusion region FD2, the second reset transistor RST2, the second source following transistor SF2 and the symmetrical first floating diffusion region FD1 of the second gating transistor SEL2 are set to the second transmission transistor TG2 far from photoelectricity The side of diode PPD.

It is the diagrammatic cross-section of pixel unit referring to Fig. 3 and Fig. 4, Fig. 4.Substrate 203 includes: p-type monocrystalline silicon Substrate and p-type epitaxial layer.Photodiode PPD is calendering electric diode (Pinned Photodiode, PPD).Two pole of photoelectricity Pipe PPD is set in substrate 203, and photodiode PPD is formed by ion implantation technology, forms p-type epitaxial layer, N-type is buried The P-N-P structure of layer 305, p-type epitaxial layer.Also that is, on the direction of Z axis, p-type epitaxial layer is formed in p-type single crystalline silicon substrate In, N-type buried layer 305 is formed in the center of p-type epitaxial layer, and P+ type sheath is formed in N-type buried layer 305.

First N-type ion area 301, the second N-type ion area 302, third N-type ion area 303 and the 4th N-type ion area 304 are both formed in p-type epitaxial layer, and the first N-type ion area 301 and the second N-type ion area 302 are formed in N-type buried layer 305 Side, third N-type ion area 303 and the 4th N-type ion area 304 are formed in the other side of N-type buried layer 305.First N-type from Sub-district 301, the second N-type ion area 302, third N-type ion area 303 and the 4th N-type ion area 304 doped with N+ type from Son.First N-type ion area 301 is used as the first floating diffusion region FD1, and third N-type ion area 303 is used as the second floating diffusion region FD2。

The grid of first transmission transistor TG1 is formed in the side of the P+ type sheath, and first resets the grid shape of crystal At between the first N-type ion area 301 and the second N-type ion area 302.The grid connection of first source following transistor SF1 should The drain of first floating diffusion region FD1, the first source following transistor SF1 connect the second N-type ion area 302 and biased electrical Pressure, the source level of the first source following transistor SF1 connect the source electrode of the first gating transistor SEL1.First gating transistor SEL1M_SEL0Drain electrode output voltage signal.

The grid of second transmission transistor TG2 is formed in the other side of the P+ type sheath, and second resets the grid of crystal It is formed between third N-type ion area 303 and the 4th N-type ion area 304.The grid of second source following transistor SF2 connects The drain of second floating diffusion region FD2, the second source following transistor SF2 connect the second N-type ion area 302 and biased electrical Pressure, the source level of the second source following transistor SF2 connect the source electrode of the second gating transistor SEL2.Second gating transistor SEL2 Drain electrode output voltage signal.

Further, please continue to refer to Fig. 4 and Fig. 6, pixel unit further includes deep trench isolation structure 306, be used for every Active region from adjacent pixel unit is set in substrate 203 around the periphery of pixel unit.Specifically, zanjon Recess isolating structure 306 is formed in p-type epitaxial layer, wherein a deep trench isolation structure 306 is formed in the second N-type ion area 302 Side far from N-type buried layer 305, another deep trench isolation structure 306 are formed in the 4th N-type ion area 304 and bury far from N-type The side of layer 305.The effect of deep trench isolation structure 306 (DTI) within the pixel is the active area being isolated between pixel, can be inhibited From the photon that adjacent pixel injects and inhibits the generation of dark current and reduce the crosstalk between pixel.

Further, please continue to refer to Fig. 4 and Fig. 6, pixel unit further includes barn door 307, is used to that light to be stopped to shine It is mapped on the region other than photodiode PPD and shields electrical interference, be set to first voltage signal output module 201 and second voltage signal output module 202 upper surface.In the present embodiment, because in pixel unit including clamper photoelectricity Diode PPD and several active circuits, clamper photodiode PPD obtain the part of optical information as light irradiation is received, but It is that other active circuits such as first voltage signal output module 201 and second voltage signal output module 202 do not need light Irradiation, if other active circuit illumination can also cause the change of active transistor performance parameters, so that cause circuit malfunction. Therefore, after the present invention completes all techniques on domain, one layer of barn door 307 is covered in all active transistor regions.It Not only there are masking and reflection to light, and play the role of shielding after the grounding to prevent electrical interference.In the present embodiment The material of barn door 307 is metal.

Further, please continue to refer to Fig. 4 and Fig. 6, pixel unit further includes lenticule 308, is used for light-ray condensing It is irradiated on the photosensitive region of photodiode, is set to the upper surface of pixel unit.In the present embodiment, in order to further mention High fill-factor FF (ratio of photosensitive area sectional area and elemental area) hides periphery using the focusing light effect of lenticule 308 The light of gear is gathered on the photosensitive region of photodiode PPD.

The working principle of the present embodiment is illustrated below with reference to Fig. 3 to Fig. 6.

First by open the first transmission transistor TG1, the first reset transistor RST1, the second transmission transistor TG2 and Second reset transistor RST2, to the first floating diffusion region FD1, the second floating diffusion region FD2 and clamper photodiode PPD into Row resets, and the residual charge in clamper of releasing photodiode PPD makes it meet complete depletion of condition, and do not adjust When optical signal processed is incident on PPD, photogenerated charge is not generated.

It is then turned off the first transmission transistor TG1, the first reset transistor RST1, the second transmission transistor TG2 and second Reset transistor RST2, clamper photodiode PPD start stored charge.

Be arranged be sent to the first transmission transistor TG1 control signal it is identical as the phase of modulation light, setting is sent to the The phase complements of the control signal of two transmission transistor TG2 and the control signal for being sent to the first transmission transistor TG1.

Emit modulation light, crystalline substance is transmitted with the first transmission transistor TG1 and second is applied to by the pulse signal of modulation light The phase relation of the control signal of body pipe TG2 opens the first transmission transistor TG1 and the second transmission transistor TG2, will build up Electric charge transfer in photodiode PPD is transmitted to the first floating diffusion region FD1 and the second floating diffusion region FD2, and first After transistor TG1 and the second transmission transistor TG2 is closed, then by opening the gating of the first gating transistor SEL1 of gating and first Transistor SEL1 read-out voltage value.

Wherein, when being measured using two tap two phase methods, it is only necessary to primary integral, specifically, pixel list Member receive object under test receive modulation light back reflection return reflected light after, obtain first voltage signal output module 201 The voltage of output is the first voltage signal PS0 that first voltage signal output module 201 of the reflected light when phase is 0 ° exports, Obtaining the voltage signal that second voltage signal output module 202 exports is second voltage signal of the reflected light when phase is 180 ° The second voltage signal PS1 that output module 202 exports；

According to formula:The flight time of modulation light is calculated, wherein T_onIt is modulation light at one Cycle T_pluseInterior level is the high time.

Further, it when measuring using two taps, four phase method, needs to be integrated twice, specifically, first Integration phase, the photodiode PPD of pixel unit receive object under test and receive the reflected light that modulation light back reflection is returned Afterwards, obtaining the voltage that first voltage signal output module 201 exports is that first voltage signal of the reflected light when phase is 0 ° is defeated The first voltage signal PS0 that module 201 exports out, it is anti-for obtaining the voltage signal that second voltage signal output module 202 exports Penetrate the second voltage signal PS1 of second voltage signal output module output of the light when phase is 180 °；The second integral stage, as After plain unit receives reflected light again, obtaining the voltage that first voltage signal output module 201 exports is reflected light in phase First voltage signal PS2 when being 90 ° obtains the reflection that the voltage that second voltage signal output module 202 exports is modulation light Second voltage signal PS3 of the light when phase is 270 °；

Embodiment three:

Referring to Fig. 7, the image sensor chip with double charge storage organization includes: pixel array 401, pixel driver Unit 402, sensing element 403 and control unit 404.

Pixel array 401, is used for output voltage signal；Pixel drive unit 402 is used to export control signal control Pixel unit work in pixel array 401, connects pixel array 401；Sensing element 403 is used to read and exports picture The voltage signal of pixel unit output in pixel array 401, connects pixel array 401；Control unit 404 is connected and is controlled Pixel array 401, pixel drive unit 402 and sensing element 403 processed.

In the present embodiment, pixel array 401 can this be several by 160 × 120,240x160,320 × 240 or 640 × 480 The pixel unit composition of kind specification.Certain pixel array 401 can also be made of the pixel unit of other specifications, concrete specification root It is configured according to the actual demand of user, so with no restriction.

The composition of pixel array 401 can be by two ways:

The first is pixel array 401 comprising multiple above-mentioned pixel units.Pixel unit includes: substrate 203, light Electric diode PPD, first voltage signal output module 201 and second voltage signal output module 202.

Further, please continue to refer to Fig. 4 and Fig. 6, pixel unit further includes barn door 307, is used to that light to be stopped to shine It is mapped on the region other than photodiode PPD and shields electrical interference, be set to first voltage signal output module 201 and second voltage signal output module 202 upper surface.In the present embodiment, because in pixel unit including clamper photoelectricity Diode and several active circuits, part of the clamper photodiode as reception light irradiation acquisition optical information, but other Active circuit such as first voltage signal output module 201 and second voltage signal output module 202 do not need the irradiation of light, If other active circuit illumination can also cause the change of active transistor performance parameters, so that cause circuit malfunction.Therefore, originally After all techniques are completed in invention on domain, one layer of barn door 307 is covered in all active transistor regions.It is not only to light Line plays the role of masking and reflection, and plays the role of shielding after the grounding and prevent electrical interference.Barn door 307 in the present embodiment Material be metal.

Further, please continue to refer to Fig. 4 and Fig. 6, pixel unit further includes lenticule 308, is used for light-ray condensing It is irradiated on the photosensitive region of photodiode PPD, is set to the upper surface of pixel unit.In the present embodiment, in order into one Step improves fill factor FF (ratio of photosensitive area sectional area and elemental area), using the focusing light effect of lenticule 308, periphery The light being blocked is gathered on the photosensitive region of photodiode PPD.

Second is that pixel unit includes: substrate 203, multiple photodiode PPD, first voltage signal output module 201 and second voltage signal output module 202.

Multiple photodiode PPD, photodiode PPD is set in substrate 203, in response to being incident on photoelectricity Reflected light and stored charge, first voltage signal output module 201 on diode PPD, are used to accumulate in two pole of photoelectricity The charge conversion of pipe PPD is voltage signal comprising first switch, the control terminal of first switch receive control signal, and first opens The input terminal of pass connects photodiode PPD, and the output end of first switch receives control signal in the control terminal of first switch When export first voltage signal；Second voltage signal output module 202 is used to that the charge in photodiode PPD will to be accumulated It is converted into voltage signal comprising second switch, the control terminal of second switch receive control signal, and the input terminal of second switch connects Connect photodiode PPD, the output end of second switch second electricity of output when the control terminal of second switch receives control signal Press signal, wherein photodiode PPD form array, photodiode PPD share first voltage signal output module 201 with And second voltage signal output module 202.

Here the composition of first voltage signal output module 201 and second voltage signal output module 202 with it is above-mentioned First voltage signal output module 201 is identical with second voltage signal output mould, therefore is not repeated to describe, and specifically please refers to The content in face.

In addition, also needing to increase red, green, blue on each pixel unit on the pixel array 401 of image sensor chip Three primary colours optical filter.

The working principle of the present embodiment is illustrated below with reference to Fig. 3 to Fig. 7.

Firstly, control unit 404 opens the first of pixel unit by the control output control signal of pixel drive unit 402 Transmission transistor TG1, the first reset transistor RST1, the second transmission transistor TG2 and the second reset transistor RST2, to first Floating diffusion region FD1, the second floating diffusion region FD2 and clamper photodiode are resetted, clamper of releasing photodiode Interior residual charge makes it meet complete depletion of condition, and when being incident on PPD without modulated optical signal, does not generate light Raw charge.

Then, control unit 404 disconnects the first transmission transistor by the control output control signal of pixel drive unit 402 TG1, the first reset transistor RST1, the second transmission transistor TG2 and the second reset transistor RST2, clamper photodiode PPD starts stored charge.

Be arranged be sent to first switch control signal it is identical as the phase of modulation light, setting is sent to the control of second switch The phase complements of signal processed and the control signal for being sent to first switch.

It opens modulation photo-emission source and emits modulation light, by the pulse signal of modulation light and be applied to the first transmission transistor The phase relation of the control signal of TG1 and the second transmission transistor TG2 opens the transmission crystal of the first transmission transistor TG1 and second Pipe TG2 will build up electric charge transfer in photodiode PPD to the first floating diffusion region FD1 and the second floating diffusion region FD2, and after the first transmission transistor TG1 and the second transmission transistor TG2 is closed, then open the first gating transistor of gating SEL1 and the first gating transistor SEL1 read-out voltage value.

Wherein, when being measured using two tap two phase methods, it is only necessary to primary integral, specifically, pixel list Member photodiode PPD receive object under test receive modulation light back reflection return reflected light after, obtain first voltage The voltage that signal output module 201 exports is that first voltage signal output module 201 of the reflected light when phase is 0 ° exports First voltage signal PS0, it in phase is 180 ° that obtain the voltage signal that second voltage signal output module 202 exports, which be reflected light, When second voltage signal output module 202 export second voltage signal PS1；

Further, it when measuring using two taps, four phase method, needs to be integrated twice, specifically, first Integration phase, pixel unit receive object under test receive modulation light back reflection return reflected light after, obtain first voltage The voltage that signal output module 201 exports is that first voltage signal output module 201 of the reflected light when phase is 0 ° exports First voltage signal PS0, it in phase is 180 ° that obtain the voltage signal that second voltage signal output module 202 exports, which be reflected light, When second voltage signal output module 202 export second voltage signal PS1；Second integral stage, pixel unit connect again After receiving reflected light, obtaining the voltage that first voltage signal output module 201 exports is first of reflected light when phase is 90 ° Voltage signal PS2, obtaining the reflected light that the voltage that second voltage signal output module 202 exports is modulation light in phase is 270 ° When second voltage signal PS3.

Voltage signal PS0, PS1, PS2, PS3 for reading into are transmitted at CPU/FPGA by sensing element 403 by parallel port.

The arithmetic element of CPU/FPGA is according to formula:Flying for modulation light is calculated The row time, wherein T_tofFor modulating light two-way time, T_pluseFor the period of modulated optical signal.

The arithmetic element of CPU/FPGA is further according to formula:The picture depth of object under test is calculated Information Depth.

Example IV:

The application proposes a kind of imaging system comprising image sensor chip and laser emitter as described above.

The imaging system of the present embodiment can be applied to 3D imaging field, gesture identification field,.

Embodiment five:

The application proposes that a kind of forming method of pixel unit with double charge storage organization, method include:

Substrate 203 is set；

Photodiode PPD is set, is set in the substrate 203, in response to being incident on the photoelectricity two Reflected light and stored charge on pole pipe PPD；

First voltage signal output module 201 is set, is used to that the charge conversion in the photodiode PPD will to be accumulated For voltage signal comprising first switch, the control terminal of the first switch receive control signal, the input of the first switch End connects the photodiode PPD, and the output end of the first switch receives described in the control terminal of the first switch The voltage signal is exported when controlling signal；And

Second voltage signal output module 202 is set, is used to that the charge conversion in the photodiode PPD will to be accumulated For voltage signal comprising second switch, the control terminal of the second switch receive control signal, the input of the second switch End connects the photodiode PPD, and the output end of the second switch receives described in the control terminal of the second switch The voltage signal is exported when controlling signal；

Wherein, setting be sent to the first switch control signal it is identical as the phase of modulation light, be arranged be sent to institute The phase complements for stating the control signal and the control signal for being sent to the first switch of second switch, emit the modulation light, When being measured using two tap two phase methods, the pixel unit receive object under test receive it is anti-after the modulation light After being emitted back towards the reflected light come, obtaining the voltage that the first voltage signal output module 201 exports is the reflected light in phase The first voltage signal PS0 of the first voltage signal output module 201 output when being 0 °, obtains the second voltage signal The voltage signal that output module 202 exports is second voltage signal output module 202 of the reflected light when phase is 180 ° The second voltage signal PS1 of output；

According to formula:The flight time of the modulation light is calculated, wherein T_onIt is described Level is the high time to modulation light in one cycle.

When being measured using two taps, four phase method, the photodiode PPD of pixel unit receives described again After reflected light, obtaining the voltage that the first voltage signal output module 201 exports is the reflected light when phase is 90 ° The first voltage signal PS2 that first voltage signal output module 201 exports, obtains the second voltage signal output module 202 The voltage of output is that second voltage signal output module 202 of the reflected light of the modulation light when phase is 270 ° exports Two voltage signal PS3；

According to formula:The flight time of the modulation light is calculated, wherein T_tofFor the modulating light two-way time, T_pluseFor the period of modulated optical signal.

Embodiment six:

A kind of depth information measuring method, method include:

Pixel array 401 is set comprising the upper pixel unit, or, comprising: substrate 203；

Multiple photodiode PPD, photodiode PPD is set in substrate 203, in response to being incident on photoelectricity Reflected light and stored charge on diode PPD,

First voltage signal output module 201, be used to accumulate photodiode PPD charge conversion be voltage letter Number comprising first switch, the control terminal of first switch receive control signal, and the input terminal of first switch connects photodiode The output end of PPD, first switch export first voltage signal when the control terminal of first switch receives control signal；And

Second voltage signal output module 202, be used to accumulate photodiode PPD charge conversion be voltage letter Number comprising second switch, the control terminal of second switch receive control signal, and the input terminal of second switch connects photodiode The output end of PPD, second switch export second voltage signal when the control terminal of second switch receives control signal,

Wherein, photodiode PPD form array, photodiode PPD share first voltage signal output module 201 with And second voltage signal output module 202；

Pixel drive unit 402 is set, is used to export the pixel unit work in control signal control pixel array 401 Make, connects pixel array 401；

Sensing element 403 is set, is used to read and the voltage of the pixel unit output in output pixel array 401 is believed Number, connect pixel array 401；

Control unit 404 is set, connect and controls pixel array 401, pixel drive unit 402 and sensing element 403；

Wherein, system opens modulation photo-emission source and sends modulation light, and control unit 404 controls pixel drive unit 402 and sends out The control signal for being sent to first switch is identical as the phase of modulation light, is sent to the control signal of second switch and is sent to first The phase complements of the control signal of switch, emitting the time span through ovennodulation every time is T_pulseModulation light pulse signal, Control unit 404 controls pixel drive unit 402 and exports to the control letter of the first switch of first voltage signal output module 201 It is number identical as the phase of laser pulse, control pixel drive unit 402 output to the second of second voltage signal output module 202 The phase complements of the control signal and laser pulse of switch, when being measured using two tap two phase methods, pixel unit is connect Receive object under test receive modulation light back reflection return reflected light after, obtain first voltage signal output module 201 export Voltage be first voltage signal PS0 that first voltage signal output module 201 of the reflected light when phase is 0 ° exports, obtain The voltage signal that second voltage signal output module 202 exports is second voltage signal output of the reflected light when phase is 180 ° The second voltage signal PS1 that module 202 exports；

According to formula:The flight time of modulation light is calculated, wherein T_tofFor The modulating light two-way time, T_pluseFor the period of modulated optical signal.

When being measured using two taps, four phase method, the photodiode PPD of pixel unit receives reflection again After light, obtaining the voltage that first voltage signal output module 201 exports is first voltage signal of the reflected light when phase is 90 ° The first voltage signal PS2 that output module 201 exports, obtaining the voltage that second voltage signal output module 202 exports is modulation The second voltage signal PS3 of second voltage signal output module output 202 of the reflected light of light when phase is 270 °；

Embodiment seven:

Referring to Fig. 8, the application proposes a kind of imaging system measurement picture depth method, comprising:

Step S701: it is configured like the command parameter of system.

It before step S701, further comprises the steps of: after imaging system enters original state, into reset state, resets When all signal of digital module is resetted.

If working under implied terms, can skip all configurations directly terminates to initialize, if desired change configuration, It then needs corresponding value to be written in register file by Serial Peripheral Interface (SPI), then initialization terminates after configuration.

Step S702: starting imaging system.

In step S702, comprising: after entering idle state, using Serial Peripheral Interface (SPI) by inputting corresponding bid value Enter measuring state to start imaging system.Measuring state is made of depth mode and grayscale mode, passes through configurable deep mode The work times of depth mode and grayscale mode are set with the registers of grayscale mode work times.

Step S703: according to the command parameter of configuration according to depth information measuring method described in embodiment six to determinand The image depth information of body measures.

Specific depth information measurement method please refers to the description of embodiment six, is not further described.

After step S703, that is, after depth work times satisfaction, grayscale mode work will be turned automatically.

Step S704: it is measured according to the image grayscale of the command parameter measuring targets of configuration.

After the grayscale mode of step S704, then the judgement of the check bit by the way that register is arranged in is to do continuously Image Acquisition still stops working.

Step S705: image depth values and gray value of image that measurement obtains are obtained, and are calculated.

Further include step S706 after step S705: to the temperature acquisition for carrying out imaging sensor, being read by parallel port CPU/FPGA outside image depth values and gray value of image to piece is calculated.

Pixel unit in the present embodiment please refers to pixel unit described in above example two, embodiment three, in this way No longer describe.

It will be understood by those skilled in the art that all or part of the steps of various methods can pass through in above embodiment Program instructs related hardware to complete, which can be stored in a computer readable storage medium, storage medium can wrap It includes: read-only memory, random access memory, disk or CD etc..

The foregoing is a further detailed description of the present application in conjunction with specific implementation manners, and it cannot be said that this Shen Specific implementation please is only limited to these instructions.For those of ordinary skill in the art to which this application belongs, it is not taking off Under the premise of from the present application design, a number of simple deductions or replacements can also be made.

Claims

1. a kind of pixel unit with double charge storage organization, which is characterized in that the pixel unit includes:

Substrate；

Photodiode is set in the substrate, in response to incident reflected light on the photodiode And stored charge；

First voltage signal output module, be used to accumulate the photodiode charge conversion be voltage signal, Including first switch, the control terminal of the first switch receives control signal, and the input terminal of the first switch connects the light Electric diode, the output end of the first switch export when the control terminal of the first switch receives the control signal One voltage signal；And

Second voltage signal output module, be used to accumulate the photodiode charge conversion be voltage signal, Including second switch, the control terminal of the second switch receives control signal, and the input terminal of the second switch connects the light Electric diode, the output end of the second switch export when the control terminal of the second switch receives the control signal Two voltage signals；

Wherein, setting be sent to the first switch control signal it is identical as the phase of modulation light, be arranged and be sent to described the The control signals of two switches and the phase complements for controlling signal for being sent to the first switch, emit the modulation light to be measured Object, when being measured using two tap two phase methods, the pixel unit receives object under test and receives the modulation After the reflected light that light back reflection is returned, the voltage for obtaining first voltage signaling module output is that the reflected light is in phase The first voltage signal PS0 of first voltage signal output module output at 0 °, obtains the second voltage signaling module The voltage signal of output is the second of second voltage signal output module output of the reflected light when phase is 180 ° Voltage signal PS1；

According to formula:The flight time of the modulation light is calculated, wherein T_onFor the modulation light Level is the high time in one cycle.

2. pixel unit as described in claim 1, which is characterized in that when being measured using two taps, four phase method, institute State pixel unit photodiode receive the reflected light again after, obtain the electricity of first voltage signaling module output Pressure is the first voltage signal PS2 of first voltage signal output module output of the reflected light when phase is 90 °, is obtained The voltage for taking the second voltage signaling module output is described second of the reflected light of the modulation light when phase is 270 ° The second voltage signal PS3 of voltage signal output module output；

3. pixel unit as described in claim 1, which is characterized in that

The photodiode is set to the center of the substrate, the first switch of the first voltage signal output module For the first transmission transistor, the first transmission transistor is set in the substrate and is set to the one of the photodiode Side, the first transmission transistor and the photodiode-couple are electric with the charge output for accumulating the photodiode Signal is pressed, the second switch of the second voltage signal output module is the second transmission transistor, second transmission transistor It is set in the substrate and symmetrical first transmission transistor is set to the other side of the photodiode, second passes Defeated transistor and the photodiode-couple are exported with the charge for accumulating the photodiode as voltage signal；

The first voltage signal output module further include:

First floating diffusion region is set in the substrate and is set to first transmission transistor far from the photoelectricity The side of diode, wherein the electric charge transfer that first transmission transistor accumulates the photodiode to described first Floating diffusion region is saved；

First reset transistor is set to the coupling photodiode in the substrate, expands described first to float The charge that area saves is dissipated to be resetted；

First source following transistor, control terminal connect first floating diffusion region, and input terminal connection described first is multiple Bit transistor；And

First gating transistor, input terminal connect the output end of first source following transistor, and first gating is brilliant The output end of body pipe exports the voltage signal；

The second voltage signal output module further include:

Second floating diffusion region is set in the substrate and is set to second transmission transistor far from the photoelectricity The side of diode, wherein the second voltage signal of the photodiode is transferred to described by second transmission transistor Second floating diffusion region is saved；

Second reset transistor is set on the substrate and couples the photodiode, expands described second to float The charge that area saves is dissipated to be resetted；

Second source following transistor, control terminal connect second floating diffusion region, and input terminal connection described second is multiple Bit transistor；And

Second gating transistor, input terminal connect the output end of second source following transistor, and second gating is brilliant The output end of body pipe exports the voltage signal.

4. pixel unit as described in claim 1, which is characterized in that the pixel unit further includes deep trench isolation structure, Its active region for being used to be isolated the adjacent pixel unit is set to the lining around the periphery of the pixel unit In bottom.

5. pixel unit as described in claim 1, which is characterized in that the pixel unit further includes barn door, is used to hinder It is in the light and is irradiated on the region other than the photodiode and shields electrical interference, be set to the first voltage The upper surface of signal output module and second voltage signal output module.

6. pixel unit as described in claim 1, which is characterized in that the pixel unit further includes lenticule, be used for by Light-ray condensing is irradiated on the photosensitive region of the photodiode, is set to the upper surface of the pixel unit.

7. a kind of image sensor chip with double charge storage organization, which is characterized in that described image sensor chip packet It includes:

Pixel array comprising multiple pixel units as described in claim 1, or, comprising:

Substrate；

Multiple photodiodes, the photodiode are set in the substrate, in response to being incident on the photoelectricity Reflected light and stored charge on diode,

Second voltage signal output module, be used to accumulate the photodiode charge conversion be voltage signal, Including second switch, the control terminal of the second switch receives control signal, and the input terminal of the second switch connects the light Electric diode, the output end of the second switch export when the control terminal of the second switch receives the control signal Two voltage signals,

Wherein, the photodiode forms array, and the photodiode shares first voltage signal output module and the Two voltage signal output modules；

Pixel drive unit is used to export the pixel unit that control signal controls in the pixel array and works, connects institute State pixel array；

Sensing element is used to read and export the voltage signal of the pixel unit output in the pixel array, connects institute State pixel array；

Control unit connects and controls the pixel array, pixel drive unit and sensing element；

Wherein, it opens modulation photo-emission source and sends modulation light, described control unit controls the pixel drive unit and is sent to institute The control signal for stating first switch is identical as the phase of modulation light, is sent to the control signal of the second switch and is sent to institute The phase complements of the control signal of first switch are stated, when measuring using two tap two phase methods, the pixel unit is connect It receives after object under test receives the reflected light that the modulation light back reflection is returned, obtains first voltage signaling module output Voltage be the reflected light when phase is 0 ° the first voltage signal output module output first voltage signal PS0, get second voltage signaling module output voltage signal be the reflected light when phase is 180 ° described in The second voltage voltage signal PS1 of second voltage signal output module output；

According to formula:The flight time of the modulation light is calculated, wherein T_onFor the modulation Level is the high time to light in one cycle.

8. image sensor chip as claimed in claim 7, which is characterized in that measured when using two taps, four phase method When, after the photodiode of the pixel unit receives the reflected light again, get the first voltage signaling module The voltage of output is the first voltage letter of first voltage signal output module output of the reflected light when phase is 90 ° Number PS2, the voltage for obtaining the second voltage signaling module output is the reflected light of the modulation light when phase is 270 ° The second voltage signal PS3 of the second voltage signal output module output；

9. image sensor chip as claimed in claim 7, which is characterized in that

The first voltage signal output module further include:

The second voltage signal output module further include:

10. image sensor chip as claimed in claim 7, which is characterized in that the pixel unit further include deep trench every It from structure, is used to be isolated the active region of the adjacent pixel unit, is arranged around the periphery of the pixel unit In the substrate.

11. image sensor chip as claimed in claim 7, which is characterized in that the pixel unit further includes barn door, For stopping light to be irradiated on the region other than the photodiode and shielding electrical interference, it is set to described The upper surface of one voltage signal output module and second voltage signal output module.

12. image sensor chip as claimed in claim 7, which is characterized in that the pixel unit further includes lenticule, For light-ray condensing to be irradiated to the photosensitive region of the photodiode, it is set to the upper surface of the pixel unit.

13. a kind of imaging system, which is characterized in that it includes the image sensing core as described in claim 6 to 12 any one Piece and laser emitter.

14. a kind of forming method of the pixel unit with double charge storage organization, which is characterized in that the described method includes:

Substrate is set；

Photodiode is set, is set in the substrate, in response to incident on the photodiode anti- Penetrate light and stored charge；

Be arranged first voltage signal output module, be used to accumulate the photodiode charge conversion be voltage believe Number comprising first switch, the control terminal of the first switch receive control signal, and the input terminal of the first switch connects institute Photodiode is stated, the output end of the first switch is defeated when the control terminal of the first switch receives the control signal First voltage signal out；And

Be arranged second voltage signal output module, be used to accumulate the photodiode charge conversion be voltage believe Number comprising second switch, the control terminal of the second switch receive control signal, and the input terminal of the second switch connects institute Photodiode is stated, the output end of the second switch is defeated when the control terminal of the second switch receives the control signal Second voltage signal out；

15. the forming method of pixel unit as claimed in claim 14, which is characterized in that when using two taps, four phase method into When row measurement, after the photodiode of the pixel unit receives the reflected light again, the first voltage signal is obtained The voltage of module output is the first electricity of first voltage signal output module output of the reflected light when phase is 90 ° Signal PS2 is pressed, it in phase is 270 ° that the voltage for obtaining second voltage signaling module output, which is the reflected light of the modulation light, When the second voltage signal output module output second voltage signal PS3；

16. a kind of depth information measuring method, which is characterized in that the described method includes:

Pixel array is set comprising multiple pixel units as described in claim 1, or, comprising:

Substrate；

Pixel drive unit is set, is used to export the pixel unit that control signal controls in the pixel array and works, connect Connect the pixel array；

Sensing element is set, is used to read and export the voltage signal of the pixel unit output in the pixel array, connects Connect the pixel array；

Control unit is set, connect and controls the pixel array, pixel drive unit and sensing element；

Wherein, it opens modulation photo-emission source and sends modulation light, described control unit controls the pixel drive unit and is sent to institute The control signal for stating first switch is identical as the phase of modulation light, is sent to the control signal of the second switch and is sent to institute The phase complements of the control signal of first switch are stated, emitting the time span through ovennodulation every time is T_pulseModulation light arteries and veins Punching, described control unit control the pixel drive unit and export to the first switch of the first voltage signal output module Control signal it is identical as the phase of the laser pulse, control the pixel drive unit export it is defeated to the second voltage signal The phase complements of the control signal and the laser pulse of the second switch of module out, are surveyed when using two tap two phase methods When amount, the pixel unit receive object under test receive the modulation light back reflection return reflected light after, described in acquisition The voltage of first voltage signaling module output is the first voltage signal output module of the reflected light when phase is 0 ° The first voltage signal PS0 of output, the voltage signal for obtaining the second voltage signaling module output are the reflected light in phase The second voltage voltage signal PS1 of second voltage signal output module output when position is 180 °；

17. depth information measuring method as claimed in claim 16, which is characterized in that carried out when using two taps, four phase method When measurement, after the photodiode of the pixel unit receives the reflected light again, the first voltage signal mode is obtained The voltage of block output is the first voltage of first voltage signal output module output of the reflected light when phase is 90 ° Signal PS2, the voltage for obtaining the second voltage signaling module output is the reflected light of the modulation light when phase is 270 ° The second voltage signal output module output second voltage signal PS3；

18. a kind of imaging system measures picture depth method characterized by comprising

Configure the command parameter of the imaging system；

Start the imaging system；

According to the command parameter of configuration according to depth information measuring method measuring targets as claimed in claim 16 Image depth information measures；

It is measured according to image grayscale information of the command parameter of configuration to the object under test；

The described image depth value and gray value of image that measurement obtains are obtained, and is calculated.