CN102647567B - CMOS (complementary metal oxide semiconductor) image sensor and a pixel structure thereof - Google Patents
CMOS (complementary metal oxide semiconductor) image sensor and a pixel structure thereof Download PDFInfo
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Abstract
The invention provides a CMOS (complementary metal oxide semiconductor) image sensor and a pixel structure thereof. A first polaroid, a liquid crystal layer with a transparent electrode structure and a second polaroid are prepared on a charge coupled device, arrangement mode of liquid crystal materials between transparent electrodes can be changed by controlling voltages of the transparent electrodes, and light polarization direction and conduction rate are controlled. The CMOS image sensor comprises the pixel structure, a processing module and a feedback control module. The control module receives electric signals and judges whether the electric signals are saturated or not, and outputs control signals to the feedback control module if the electric signals are saturated signals. The feedback control module outputs control voltage to the pixel structure so as to reduce light conduction rate gradually and feeds information back to the processing module, and the processing module computes practical light intensity value according to feedback information and the electric signals until the electric signals output by the pixel structure are unsaturated signal. Light intensity value monitored by the CMOS image sensor is improved greatly, and dynamic range of light sensing is enlarged greatly.
Description
Technical field
The invention belongs to semiconductor applications, particularly relate to a kind of cmos image sensor and dot structure thereof.
Background technology
Cmos image sensor is the manufacture of a kind of CMOS of use manufacturing process, the optical signalling of image is converted to the signal of telecommunication for the semiconductor device transmitted and process.Cmos image sensor is generally made up of photosensitive region and signal processing circuit.Cmos image sensor common is at present active pixel type imageing sensor (APS).
Existing cmos image sensor comprises CMOS digital-to-analog circuit and pixel unit circuit array is formed, the number of the transistor included by a described pixel unit circuit, existing cmos image sensor is divided into 3T type structure and 4T type structure, can also has 5T type structure.
As shown in Figure 1, for a kind of equivalent circuit structure figure of pixel unit circuit of cmos image sensor of existing 3T type structure, comprise: a photodiode 10 (Photo Diode, PD), for carrying out opto-electronic conversion when exposing, convert the light signal received to the signal of telecommunication, described photodiode 10 comprises p type island region and N-type region, described p type island region ground connection.
A reset transistor M1, for resetting to described photodiode 10 before exposure, resetting is controlled by reset signal Reset signal.In FIG, described reset transistor M1 selects a NMOS tube, the source electrode of described reset transistor M1 is connected with the N-type region of described photodiode 10, the source electrode of described reset transistor M1 is also that a sense node N1 is also called floating diffusion region (Floating Diffusion, FD) simultaneously; The drain electrode of described reset transistor M1 meets power supply Vdd, and described power supply Vdd is a positive supply.When described reset signal Reset is high level, the N-type region of described photodiode 10 is also connected to power supply Vdd by described reset transistor M1 conducting, under the effect of described power supply Vdd, make described photodiode 10 reverse-biased and the electric charge of whole accumulations of described photodiode 10 can be removed, realizing resetting.Described reset transistor M1 also can be connected by multiple NMOS tube and be formed or formed by multiple NMOS tube parallel connection, also can replace described NMOS tube by PMOS.
An amplifier transistor M2, is also one source pole follower, amplifies for the signal of telecommunication produced by described photodiode 10.In FIG, described amplifier transistor M2 selects a NMOS tube, the grid of described amplifier transistor M2 connects the N-type region of described photodiode 10, and the drain electrode of described amplifier transistor M2 meets described power supply Vdd, and the source electrode of described amplifier transistor M2 is the output of amplifying signal.Described amplifier transistor M2 also can be connected by multiple NMOS tube and be formed or formed by multiple NMOS tube parallel connection.
A row selecting transistor M3, exports for the amplifying signal exported by the source electrode of described amplifier transistor M2.In FIG, described row selecting transistor M3 selects a NMOS tube, the grid of described row selecting transistor M3 meets row selection signal Rs, and the source electrode of described row selecting transistor M3 connects the source electrode of described amplifier transistor M2, and the drain electrode of described row selecting transistor M3 is output.
As shown in Figure 2, be a kind of equivalent circuit structure figure of pixel unit circuit of cmos image sensor of existing 4T type structure.Compared to 3T type structure, the pixel unit circuit structure chart of the cmos image sensor of existing 4T type structure adds a transfering transistor M4, and described transfering transistor M4 is used for the signal of telecommunication that described photodiode 10 produces to be input to described sense node N1.In fig. 2, described transfering transistor M4 selects a NMOS tube, the grid of described transfering transistor M4 switches through shifting signal TX, the source electrode of described transfering transistor M4 connects the N-type region of described photodiode 10, and the drain electrode of described transfering transistor M4 meets the source electrode of described reset transistor M1 and described sense node N1.
Material is divided three classes, gaseous state, liquid state, solid-state, that is familiar with state of matter along with people deepens continuously, find that material is except above-mentioned tri-state, also there is ionic state (plasmas), amorphous solid-state (amorplhous solids), liquid crystal state (liquidcrystals), superconducting state (superconductors) neutron state (neutron state) etc.Find the liquid crystal material of more than hundreds thousand of kinds so far, wherein, being classified as follows of liquid crystal material:
Lysotropic liquid crystal: the liquid crystal state formed when Cucumber being dissolved in another material, is therefore known as lysotropic liquid crystal.Parents' molecule many genus lysotropic liquid crystal, suds are a kind of typical lysotropic liquid crystals.Cell membrane is the double-deck lysotropic liquid crystal that ester quasi-molecule is formed.Lysotropic liquid crystal is extensively present in nature, and particularly in organism, it is not only widely used in the every field of human lives, and in biophysics, biochemistry and bionics field attract attention deeply.The structure of a lot of organism, as the metabolism of the living matters such as brain, nerve, muscle, blood or life, the biological phenomenas such as consciousness, information transmission are all relevant with this liquid crystal.
Thermotropic liquid crystal: Yin Wendu and differently occur liquid crystal state.As wrist-watch, LCD TV, computer LCDs etc. be exactly that thermotropic liquid crystal is mainly divided into: (1) nematic phase (nematic): the molecule of composition as the common fluid in disorder distribution.Optical electromagnetic character presents the anisotropy similar to bright body, is referred to as three dimensional anisotropic fluid.(2) smectic phase (Smetic): the molecular center of composition has cycle sequence in a direction, rodlike molecule composition layer, in layer, molecular long axis is parallel to each other, its direction perpendicular to aspect or can become oblique arrangement (3) spiral phase (cholesteric) with aspect: if the molecule formed has chirality, molecularly oriented can form Torsion coil structure in space.Therefore its optical characteristics has strong circular dichroism and other photolytic activity (being also helicity) this kind of liquid crystal molecule is flat, arrangement stratification, in layer, molecule is parallel to each other, molecular long axis is parallel to layer plane, the molecular long axis direction of different layers slightly changes, and the normal direction along layer is arranged in helical structure.Spiral shell square P refers to that get back to initial orientation again, this periodic interlamellar spacing is called the spiral shell square of spiral phase liquid crystal after the change of 360 ° is experienced in the arrangement of different layers molecular long axis along the hand of spiral.
TN (Twist Nematic) twisted nematic liquid crystal: nematic crystal is clipped in the middle of two sheet glass, the surface of this glass is first coated with layer of transparent conductive film ITO (tin indium oxide) to be used as electrode, then on the glass having membrane electrode, be coated with orientation layer PI (polyimides), with make liquid crystal along one specific and be parallel to glass surface direction arrangement.The nature of liquid crystal has the distortion of 90 degree, and utilize electric field that liquid crystal molecule can be made to rotate, the birefringence of liquid crystal changes with the direction of liquid crystal, and the result of impact is that polarised light rotates through TN type liquid crystal rear polarizer direction.As long as select suitable thickness to make the polarization direction of polarised light just change 90 degree, just can utilize two parallel polaroids make light completely not by.And enough large voltage can make liquid crystal orientation parallel with direction of an electric field, such polarisation of light direction would not change, and light is just by second polaroid.So, just can control the break-make of light.
Nematic crystal is clipped in the middle of two sheet glass, the surface of this glass is first coated with layer of transparent conductive film ITO (tin indium oxide) to be used as electrode, then on the glass having membrane electrode, be coated with orientation layer PI (polyimides), with make liquid crystal along one specific and be parallel to glass surface direction arrangement.The nature of liquid crystal has the distortion of 90 degree, and utilize electric field that liquid crystal molecule can be made to rotate, the birefringence of liquid crystal changes with the direction of liquid crystal, and the result of impact is that polarised light rotates through TN type liquid crystal rear polarizer direction.As long as select suitable thickness to make the polarization direction of polarised light just change 90 degree, just can utilize two parallel polaroids make light completely not by.And enough large voltage can make liquid crystal orientation parallel with direction of an electric field, such polarisation of light direction would not change, and light is just by second polaroid.So, just can control the light and shade of light.TN type is commonly used in electronic watch, the simple displaying aspects such as calculator.
STN (Super Twist Nematic) super-twist nematic liquid crystal: identical with the displaying principle of TN type liquid crystal, just incident light is rotated 180 ~ 270 degree by it, instead of 90 degree.And simple TN type liquid crystal display itself only has light and shade two kinds change.Stn liquid crystal is then based on light green and orange.Liquid crystal display screen adds one deck compensate film and can make it to become black and white, be called film compensated super twisted nematic liquid crystal (FSTN).If but add a colored filter at the monochromatic stn liquid crystal display of tradition, and each pixel in monochromatic display matrix is divided into three sub-pixels, respectively by colored filter display Red Green Blue, just color can be demonstrated, be called CSTN (Color STN), Here it is everybody usually said pseudo-color screen.STN, FSTN and CSTN are commonly used to do mobile phone display screen, game machine screen etc.
Existing cmos image sensor is when photosensitive, all make incident light be directly incident on photo-sensitive cell, this cmos image sensor often exceeds its measuring range when needing detection light intensity larger and causes being difficult to measure actual light intensity value, and existing cmos image sensor is when incident light is directly incident on photo-sensitive cell, its photosensitive dynamic range is less, is unfavorable for application.
Summary of the invention
The shortcoming of prior art in view of the above, the object of the present invention is to provide a kind of cmos image sensor and dot structure thereof, is difficult to the larger light intensity value of accurate measurements and the less problem of dynamic range for solving cmos image sensor in prior art.
For achieving the above object and other relevant objects, the invention provides a kind of dot structure of cmos image sensor, at least comprise:
Photosensitive structure, comprising: photo-sensitive cell; First polarizer, is incorporated into described photosensitive member surface, has the first polarization direction; Liquid crystal light guide structure, comprise be incorporated into described first polarizer the first transparency conducting layer, be incorporated into the liquid crystal layer of described first transparency conducting layer and be incorporated into the second transparency conducting layer of described liquid crystal layer, first, second transparency conducting layer described controls the orientation of described liquid crystal layer by external voltage signal, to control polarisation of light direction; Second polarizer, is incorporated into described liquid crystal light guide structure, has the second polarization direction;
Pixel readout circuit, is connected to described photo-sensitive cell, reads for the signal of telecommunication produced by described photosensitive structure.
In the dot structure of cmos image sensor of the present invention, the phase difference of described first polarization direction and the second polarization direction is 0 ~ 90 degree.
Preferably, the phase difference of described first polarization direction and the second polarization direction is 90 degree.
In the dot structure of cmos image sensor of the present invention, the photoconduction passband of described first polarizer, liquid crystal layer and the second polarizer co-controlling dot structure.
In the dot structure of cmos image sensor of the present invention, described photo-sensitive cell is optical gate, PN type photodiode or PIN type photodiode.
In the dot structure of cmos image sensor of the present invention, the material of described first transparency conducting layer and the second transparency conducting layer is tin indium oxide (ITO), antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO) or aluminium-doped zinc oxide (AZO).
In the dot structure of cmos image sensor of the present invention, described liquid crystal layer is twisted nematic liquid crystal.
In the dot structure of cmos image sensor of the present invention, described pixel readout circuit is the pixel readout circuit of 3T type structure, 4T type structure or 5T type structure.
The present invention also provides a kind of cmos image sensor comprising arbitrary dot structure as above, at least comprises: dot structure, for controlling photoconduction passband and exporting after converting light signal to the signal of telecommunication; Processing module, is connected to described dot structure, for receiving the signal of telecommunication that described dot structure exports, and judge whether it is saturation signal, if so, then exports control signal, if not, then the logical described signal of telecommunication calculate the light intensity of incident light according to the photoconduction passband of described dot structure; Feedback control module, be connected to described processing module and described dot structure, for when receiving the control signal that described processing module exports, export control voltage to control the photoconduction passband of described pixel knot, and send feedback signal to feed back the information of the photoconduction passband of described pixel knot to described processing module.
In cmos image sensor of the present invention, described control voltage puts on the first transparency conducting layer and second transparency conducting layer of described dot structure respectively, to control the photoconduction passband of described dot structure.
In cmos image sensor of the present invention, when the signal of telecommunication that described processing module receives is judged to be saturation signal, described feedback control module exports control voltage to reduce the photoconduction passband of described dot structure, until the described signal of telecommunication is judged to be unsaturation signal to described dot structure.
As mentioned above, cmos image sensor of the present invention and dot structure thereof, there is following beneficial effect: dot structure of the present invention prepares the first polarizer on photo-sensitive cell, there is liquid crystal layer and second polarizer of transparent electrode structure, liquid crystal arrangement mode between can being changed by the voltage controlling described transparency electrode, thus control light polarization direction and on-state rate.Cmos image sensor of the present invention also comprises processing module and feedback control module, described control module receives the signal of telecommunication of described dot structure output and judges, if during saturation signal, output control signals to feedback control module, described feedback control module exports control voltage to reduce photoconduction passband gradually to described dot structure upon the reception of control signals, and to described processing module feedback information, until when the signal of telecommunication that described dot structure exports is unsaturation signal, described processing module feedback information and the signal of telecommunication calculate actual light intensity value.Present invention greatly improves the light intensity value that cmos image sensor can be monitored, thus greatly increase photosensitive dynamic range.Present invention process is simple, practical, is applicable to industrial production.
Accompanying drawing explanation
Fig. 1 is shown as the equivalent circuit structure schematic diagram of the pixel unit circuit of the cmos image sensor of 3T type structure of the prior art.
Fig. 2 is shown as the equivalent circuit structure schematic diagram of the pixel unit circuit of the cmos image sensor of 4T type structure of the prior art.
Fig. 3 is shown as the structural representation of the dot structure of cmos image sensor in embodiments of the invention 1.
Fig. 4 is shown as the structural representation of cmos image sensor in embodiments of the invention 1.
Fig. 5 is shown as the operation workflow schematic diagram of cmos image sensor in embodiments of the invention 1.
Fig. 6 is shown as the structural representation of the dot structure of cmos image sensor in embodiments of the invention 2.
Fig. 7 is shown as the structural representation of cmos image sensor in embodiments of the invention 2.
Fig. 8 is shown as the operation workflow schematic diagram of cmos image sensor in embodiments of the invention 2.
Fig. 9 is shown as the structural representation of the dot structure of cmos image sensor in embodiments of the invention 3.
Figure 10 is shown as the structural representation of cmos image sensor in embodiments of the invention 3.
Figure 11 is shown as the operation workflow schematic diagram of cmos image sensor in embodiments of the invention 3.
Figure 12 is shown as the structural representation of the dot structure of cmos image sensor in embodiments of the invention 4.
Figure 13 is shown as the structural representation of cmos image sensor in embodiments of the invention 4.
Figure 14 is shown as the operation workflow schematic diagram of cmos image sensor in embodiments of the invention 4.
Element numbers explanation
101 photo-sensitive cells
102 first polarizers
103 first transparency conducting layers
104 liquid crystal layers
105 second transparency conducting layers
106 second polarizers
107 protective layers
201 transfering transistors
202 floating diffusion regions
203 reset transistors
204 amplifier transistors
205 gate transistors
301 dot structures
302 processing modules
303 feedback control module
Embodiment
Below by way of specific instantiation, embodiments of the present invention are described, those skilled in the art the content disclosed by this specification can understand other advantages of the present invention and effect easily.The present invention can also be implemented or be applied by embodiments different in addition, and the every details in this specification also can based on different viewpoints and application, carries out various modification or change not deviating under spirit of the present invention.
Refer to Fig. 3 to Figure 14.It should be noted that, the diagram provided in the present embodiment only illustrates basic conception of the present invention in a schematic way, then only the assembly relevant with the present invention is shown in graphic but not component count, shape and size when implementing according to reality is drawn, it is actual when implementing, and the kenel of each assembly, quantity and ratio can be a kind of change arbitrarily, and its assembly layout kenel also may be more complicated.
Embodiment 1
Refer to Fig. 3 ~ Fig. 4, as shown in the figure, the invention provides a kind of cmos image sensor, at least comprise:
Dot structure 301, for controlling photoconduction passband and exporting after converting light signal to the signal of telecommunication, comprising:
Photosensitive structure, comprising: photo-sensitive cell 101; First polarizer 102, is incorporated into described photo-sensitive cell 101 surface, has the first polarization direction; Liquid crystal light guide structure, comprise be incorporated into described first polarizer 102 the first transparency conducting layer 103, be incorporated into the liquid crystal layer 104 of described first transparency conducting layer 103 and be incorporated into the second transparency conducting layer 105 of described liquid crystal layer 104, described first transparency conducting layer 103, second transparency conducting layer 105 controls the orientation of liquid crystal material in described liquid crystal layer 104 by external voltage signal, to control polarisation of light direction; Second polarizer 106, is incorporated into described liquid crystal light guide structure, has the second polarization direction; And pixel readout circuit, be connected to described photo-sensitive cell 101, read for the signal of telecommunication that described photosensitive structure is produced.
Described photo-sensitive cell 101 is optical gate, PN type photodiode or PIN type photodiode, is PN type photodiode in the present embodiment.Certainly, in other embodiments, described photo-sensitive cell 101 also can be the device with ligh-induced effect of other all expections.
The phase difference of described first polarization direction and the second polarization direction is 0 ~ 90 degree.The photoconduction passband of described first polarizer 102, liquid crystal layer 104 and the second polarizer 106 co-controlling dot structure.In the present embodiment, the phase difference of described first polarization direction and the second polarization direction is 90 degree.Therefore, if described liquid crystal layer 104 does not change the polarization direction of incident light, the light intensity be then radiated on described photo-sensitive cell 101 is zero, light intensity changes along with liquid crystal layer 104 liquid crystal arrangement direction, namely photoconduction passband changes along with liquid crystal layer 104 liquid crystal arrangement direction, when the polarization direction that described liquid crystal layer 104 changes incident light is 90 degree, photoconduction passband is maximum, and incident intensity is maximum.
The material of described first transparency conducting layer 103 and the second transparency conducting layer 105 is ITO, ATO, FTO or AZO, and in the present embodiment, the material of described first transparency conducting layer 103 and the second transparency conducting layer 105 is ITO.Certainly, in other embodiments, the material of described first transparency conducting layer 103 and the second transparency conducting layer 105 also can be the transparent conductive material of other expection.
In the present embodiment, described second polarizer 106 is also provided with protective layer 107, and protective layer 107 is SiO
2, the conventional dielectric material such as SiN or SiON.
In the present embodiment, described liquid crystal layer 104 is twisted nematic liquid crystal.Certainly, in other embodiments, described liquid crystal layer 104 also can be STN (Super Twist Nematic) super-twist nematic liquid crystal etc., simultaneously, adaptive change is also done, to reach required effect in the polarization direction of described first polarizer 102 and the second polarizer 106.
Described pixel readout circuit is the pixel readout circuit of 3T type structure, 4T type structure or 5T type structure, and in the present embodiment, described pixel readout circuit is the pixel readout circuit of 4T type structure.It comprises transfering transistor 201, floating diffusion region 202, reset transistor 203, amplifier transistor 204 and row selecting transistor 205.
Described cmos image sensor also comprises processing module 302, be connected to described dot structure 301, for receiving the signal of telecommunication that described dot structure 301 exports, and judge whether it is saturation signal, if, then export control signal, if not, then calculate the light intensity of incident light by the described signal of telecommunication and according to the photoconduction passband of described dot structure 301; Feedback control module 303, be connected to described processing module 302 and described dot structure 301, for when receiving the control signal that described processing module 302 exports, export control voltage to control the photoconduction passband of described pixel knot, and send feedback signal to feed back the information of the photoconduction passband of described pixel knot to described processing module 302.
Described control voltage puts on the first transparency conducting layer 103 and the second transparency conducting layer 105 of described dot structure 301 respectively, to control the photoconduction passband of described dot structure 301.Particularly, described feedback control module 303 has connection the first transparency conducting layer 103 of described dot structure 301 and two outputs of the second transparency conducting layer 105, for applying voltage to the liquid crystal layer 104 of described dot structure 301, photoconduction passband can be controlled by control voltage thus controlling light intensity.
When the signal of telecommunication that described processing module 302 receives is judged to be saturation signal, described feedback control module 303 exports control voltage to reduce the photoconduction passband of described dot structure 301, until the described signal of telecommunication is judged to be unsaturation signal to described dot structure 301.
In concrete implementation process, first, described feedback control module 303 first, second transparency conducting layer 105 to described dot structure 301 applies control voltage, the photoconduction passband of described dot structure 301 is made to be in a higher level, when light incides described photo-sensitive cell 101, described photo-sensitive cell 101 converts light signal to the signal of telecommunication, and reads out to described processing module 302 by described pixel readout circuit.Described processing module 302 is when receiving the described signal of telecommunication, it is judged, situation has two kinds: 1) if the described signal of telecommunication is judged as unsaturation signal, then calculated the incident intensity of dot structure 301 by described feedback control module 303 feedack and the received signal of telecommunication, namely actual light intensity value.2) if the described signal of telecommunication is judged as saturation signal, then described processing module 302 exports control signal to described feedback control module 303, when described feedback control module 303 receives control signal, adjust the control voltage that exports to described dot structure 301 to reduce its photoconduction passband.If the signal of telecommunication received still for saturation signal, then repeats said process, till the signal of telecommunication received until described processing module 302 is judged as unsaturation signal.If unsaturation signal, then processing procedure is as situation 1) as described in.Idiographic flow as shown in Figure 5.
Embodiment 2
Refer to Fig. 6 ~ Fig. 8, the present embodiment provides a kind of cmos image sensor, at least comprises:
Pel array 401, rearranged by multiple dot structure, the basic structure of described dot structure is as embodiment 1, wherein, first, second transparency conducting layer described is connected to ground wire and a transistor 206, for controlling the voltage on first, second transparency conducting layer described, described pixel readout circuit is the pixel readout circuit of 3T type structure.
Row selects module 407 and column selection module 408, is all connected to described pel array 401, for controlling the scanning direction of described pel array 401.
Variable gain amplifier (PGA) 402, is connected to described pel array 401, amplifies for the signal of telecommunication exported described pel array 401 and exports according to the photoconduction passband in dot structure.
AD sample circuit 406, is connected to described variable gain amplifier 402, is transformed into digital signal for the signal of telecommunication exported by described variable gain amplifier 402.
Processing module 403, be connected to described variable gain amplifier 402, for receiving the signal of telecommunication that described variable gain amplifier 402 exports, and judge whether it is saturation signal, if so, then control signal is exported, if not, then by the described signal of telecommunication and according in described pel array 401 respectively the photoconduction passband of this dot structure calculate the light intensity of incident light, and the multiplication factor controlling described variable gain amplifier 402 is with the incident intensity enabling the signal of telecommunication after amplification reflect this dot structure strictly according to the facts.
Feedback control module 404, be connected to described processing module 403 and described pel array 401, for when receiving the control signal that described processing module 403 exports, export control voltage to control the photoconduction passband of respectively this pixel knot in described pel array 401, and send feedback signal to feed back the information of the photoconduction passband of respectively this pixel knot in described pel array 401 to described processing module 403.
Reset circuit 405, for when described processing module 403 is saturation signal to the signal determining that the dot structure in described pel array 401 exports, resets to this dot structure.
Particularly, described row selects module 407 or column selection module 408 to send sweep signal to described pel array 401, make the gate transistor gating of described dot structure pixel readout circuit, the signal of telecommunication that described pel array 401 produces reads out to described variable gain amplifier 402, the signal of telecommunication through amplifying exports described processing module 403 to, described processing module 403, when receiving the described signal of telecommunication, judges it, and situation has two kinds:
1) signal of telecommunication exported in described pel array 401 is judged as to the dot structure of unsaturation signal, the incident intensity of this dot structure directly can be calculated by described feedback control module 404 feedack and the received signal of telecommunication, namely actual light intensity value, according to the photoconduction passband in dot structure, output after variable gain amplifier (PGA) 402 amplifies, and by AD sample circuit 406, Image Reconstruction is carried out to it.
2) signal of telecommunication exported in described pel array 401 is judged as to the dot structure of saturation signal, described reset circuit sends its signal of telecommunication of reset enable signal and resets, described processing module 403 exports control signal to described feedback control module 404, when described feedback control module 404 receives control signal, adjust the control voltage that exports to this dot structure to reduce its photoconduction passband.If the signal of telecommunication received still for saturation signal, then repeats said process, till the signal of telecommunication receiving this dot structure until described processing module 403 is judged to be unsaturation signal.If be finally judged to be unsaturation signal, then processing procedure is as situation 1) as described in, finally draw the pixel of all dot structures and obtain the image reconstructed.
Embodiment 3
Refer to Fig. 9 ~ Figure 11, the present embodiment provides a kind of cmos image sensor, at least comprises:
Pel array 501, rearranged by multiple dot structure, the basic structure of described dot structure is as embodiment 1, wherein, first, second transparency conducting layer described is connected to ground wire and a transistor 206, for controlling the voltage on first, second transparency conducting layer described, described pixel readout circuit is the pixel readout circuit of 4T type structure.
Row selects module 507 and column selection module 508, is all connected to described pel array 501, for controlling the scanning direction of described pel array 501.
Variable gain amplifier (PGA) 502, is connected to described pel array 501, amplifies for the signal of telecommunication exported described pel array 501 and exports according to the photoconduction passband in dot structure.
AD sample circuit 506, is connected to described variable gain amplifier 502, is transformed into digital signal for the signal of telecommunication exported by described variable gain amplifier 502.
Processing module 503, be connected to described variable gain amplifier 502, for receiving the signal of telecommunication that described pel array 501 exports, and judge whether it is saturation signal, if so, then control signal is exported, if not, then by the described signal of telecommunication and according in described pel array 501 respectively the photoconduction passband of this dot structure calculate the light intensity of incident light, and the multiplication factor controlling described variable gain amplifier 502 is with the incident intensity enabling the signal of telecommunication after amplification reflect this dot structure strictly according to the facts.
Feedback control module 504, be connected to described processing module 503 and described pel array 501, for when receiving the control signal that described processing module 503 exports, export control voltage to control the photoconduction passband of respectively this pixel knot in described pel array 501, and send feedback signal to feed back the information of the photoconduction passband of respectively this pixel knot in described pel array 501 to described processing module 503.
Reset circuit 505, for when described processing module 503 is judged to be saturation signal to the signal of telecommunication that the arbitrary dot structure in described pel array 501 exports, all dot structures resetted in described pel array 501.
Particularly, described row selects module 507 or column selection module 508 to send sweep signal to described pel array 501, make the gate transistor gating of described dot structure pixel readout circuit, the signal of telecommunication that all dot structures of described pel array 501 produce reads out to described variable gain amplifier, the signal of telecommunication through amplifying exports described processing module to, described processing module 503, when receiving the described signal of telecommunication, judges it, and situation has two kinds:
1) when the signal of telecommunication exported for dot structures all in described pel array 501 is all judged to be unsaturation signal, the incident intensity of respectively this dot structure directly can be calculated by described feedback control module 504 feedack and the received signal of telecommunication, namely actual light intensity value, according to the photoconduction passband in dot structure, output after variable gain amplifier (PGA) 502 amplifies the signal of telecommunication that each this dot structure exports, and by AD sample circuit 506, Image Reconstruction is carried out to the signal after each this dot structure amplifies.
2) signal of telecommunication exported for all dot structures of described pel array 501 judges, when the signal of telecommunication that one of them or more than one dot structure export is judged as saturation signal, the signal of telecommunication that described reset circuit sends all dot structures of pel array 501 described in reset enable signal resets, described processing module 503 exports control signal to described feedback control module 504, when described feedback control module 504 receives control signal, adjust to respectively this is judged to be that the control voltage of the dot structure output of saturation signal is to reduce its photoconduction passband.If the signal of telecommunication received still is determined with saturation signal, then repeat said process, till all signals of telecommunication received until described processing module 503 are judged as unsaturation signal.If when all dot structures are all judged to be unsaturation signal, processing procedure is as situation 1) as described in, finally draw the pixel of all dot structures and obtain the image reconstructed.
Embodiment 4
Refer to Figure 12 ~ Figure 14, the present embodiment provides a kind of cmos image sensor, at least comprises:
Pel array 601, rearranged by multiple dot structure, the basic structure of described dot structure as embodiment 1, wherein, first, second transparency conducting layer described is connected to ground wire and a transistor 206, for controlling the voltage on first, second transparency conducting layer described.Described pixel readout circuit is the pixel readout circuit of 4T type structure, in the pixel readout circuit of described 4T type structure, transfer transistor gate in described pixel readout circuit is connected with a switching transistor 207, carries out signal output for selecting specific dot structure.
Row selects module 607 and column selection module 608, all be connected to described pel array 601, for controlling the scanning direction of described pel array 501, and select to control the transfer of the some signal of specific one or more than one dot structure by described switching transistor 207.
AD sample circuit 602, is connected to described pel array 601, is transformed into digital signal for the signal of telecommunication exported by described pel array 601.
Processing module 603, be connected to described AD sample circuit 602 and described row, column selection module 607 and 608, for receiving the signal that described AD sample circuit 602 exports, and judge whether it is saturation signal, if, then export control signal, if not, then calculate the light intensity of incident light according to the iterations that specific pixel structure in described pel array 601 is judged as saturation signal by the described signal of telecommunication.
Feedback control module 604, be connected to described processing module 603 and described pel array 601, for when receiving the control signal that described processing module 603 exports, export control voltage to control the photoconduction passband of specific pixel knot in described pel array 601, and send feedback signal to feed back the information of the control voltage of specific pixel knot in described pel array 601 to described processing module 603.
Reset circuit 605, for other dot structure in the described pel array 601 that resets except chosen dot structure.
Particularly, described row selects module 607 or column selection module 608 to select specific dot structure to carry out signal of telecommunication reading by the described switching transistor 207 of control and described gate transistor, the signal of telecommunication read exports described processing module to after AD sample circuit 602 is changed, described processing module 603 is when receiving the described signal of telecommunication, it is judged, situation has two kinds: when signal determining corresponding to the specific pixel structure 1) chosen for described pel array 601 is unsaturation signal, the incident intensity of respectively this dot structure directly can be calculated by described feedback control module 604 feedack and the received signal of telecommunication, namely actual light intensity value, and carry out Image Reconstruction, 2) when the signal determining that the specific pixel structure chosen of described pel array 601 is corresponding is saturation signal, described processing module 603 exports control signal to described feedback control module 604, when described feedback control module 604 receives control signal, adjust to respectively this is judged to be that the control voltage of the dot structure output of saturation signal is to reduce its photoconduction passband.If the signal received still is judged to be saturation signal, then repeat said process, till the signal received until described processing module 603 is judged as unsaturation signal.If when signal determining corresponding to the specific pixel structure chosen is unsaturation signal, then carry out Image Reconstruction according to the iterations of control voltage in this specific pixel structure.In the process, not chosen dot structure hold reset state.
As mentioned above, dot structure of the present invention prepares the first polarizer on photo-sensitive cell, there is liquid crystal layer and second polarizer of transparent electrode structure, the liquid crystal arrangement mode between can being changed by the voltage controlling described transparency electrode, thus control light polarization direction and on-state rate.Cmos image sensor of the present invention comprises dot structure, processing module and feedback control module, described control module receives the signal of telecommunication of described dot structure output and judges, if during saturation signal, output control signals to feedback control module, described feedback control module exports control voltage to reduce photoconduction passband gradually to described dot structure upon the reception of control signals, and to described processing module feedback information, until when the signal of telecommunication that described dot structure exports is unsaturation signal, described processing module feedback information and the signal of telecommunication calculate actual light intensity value.Present invention greatly improves the light intensity value that cmos image sensor can be monitored, thus greatly increase photosensitive dynamic range.Present invention process is simple, practical, is applicable to industrial production.So the present invention effectively overcomes various shortcoming of the prior art and tool high industrial utilization.
Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any person skilled in the art scholar all without prejudice under spirit of the present invention and category, can modify above-described embodiment or changes.Therefore, such as have in art usually know the knowledgeable do not depart from complete under disclosed spirit and technological thought all equivalence modify or change, must be contained by claim of the present invention.
Claims (9)
1. a dot structure for cmos image sensor, is characterized in that, described dot structure is single pixel, and it at least comprises:
Photosensitive structure, comprising:
Photo-sensitive cell;
First polarizer, is incorporated into described photosensitive member surface, has the first polarization direction;
Liquid crystal light guide structure, comprise be incorporated into described first polarizer the first transparency conducting layer, be incorporated into the liquid crystal layer of described first transparency conducting layer and be incorporated into the second transparency conducting layer of described liquid crystal layer, first, second transparency conducting layer described controls the orientation of described liquid crystal layer by external voltage signal, to control polarisation of light direction;
Second polarizer, is incorporated into described liquid crystal light guide structure, has the second polarization direction;
Each dot structure is integrated with first polarizer corresponding with single pixel, liquid crystal light guide structure and the second polarizer;
Pixel readout circuit, is connected to described photo-sensitive cell, reads for the signal of telecommunication produced by described photosensitive structure.
2. the dot structure of cmos image sensor according to claim 1, is characterized in that: the phase difference of described first polarization direction and the second polarization direction is 0 ~ 90 degree.
3. the dot structure of cmos image sensor according to claim 2, is characterized in that: the phase difference of described first polarization direction and the second polarization direction is 90 degree.
4. the dot structure of cmos image sensor according to claim 1, is characterized in that: the photoconduction passband of described first polarizer, liquid crystal layer and the second polarizer co-controlling dot structure.
5. the dot structure of cmos image sensor according to claim 1, is characterized in that: the material of described first transparency conducting layer and the second transparency conducting layer is tin indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide or aluminium-doped zinc oxide.
6. the dot structure of cmos image sensor according to claim 1, is characterized in that: described liquid crystal layer is twisted nematic liquid crystal.
7. comprise a cmos image sensor for the dot structure as described in any one of claim 1 ~ 6, it is characterized in that, at least comprise:
Dot structure, for controlling photoconduction passband and exporting after converting light signal to the signal of telecommunication;
Processing module, is connected to described dot structure, for receiving the signal of telecommunication that described dot structure exports, and judge whether it is saturation signal, if so, then exports control signal, if not, then the light intensity of incident light is calculated by the described signal of telecommunication and according to the photoconduction passband of described dot structure;
Feedback control module, be connected to described processing module and described dot structure, for when receiving the control signal that described processing module exports, export control voltage to control the photoconduction passband of described dot structure, and send feedback signal to feed back the information of the photoconduction passband of described dot structure to described processing module.
8. cmos image sensor according to claim 7, is characterized in that: described control voltage puts on the first transparency conducting layer and second transparency conducting layer of described dot structure respectively, to control the photoconduction passband of described dot structure.
9. cmos image sensor according to claim 7, it is characterized in that: when the signal of telecommunication that described processing module receives is judged to be saturation signal, described feedback control module exports control voltage to reduce the photoconduction passband of described dot structure, until the described signal of telecommunication is judged to be unsaturation signal to described dot structure.
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| CN108919553B (en) * | 2018-07-26 | 2023-03-14 | 京东方科技集团股份有限公司 | Display panel, display device and manufacturing method of display panel |
| CN110265417A (en) * | 2019-06-12 | 2019-09-20 | 德淮半导体有限公司 | Imaging sensor and forming method thereof |
| CN110708453A (en) * | 2019-11-12 | 2020-01-17 | Oppo广东移动通信有限公司 | Image sensor, camera module, terminal and imaging method |
| CN110784633B (en) * | 2019-11-12 | 2021-07-16 | Oppo广东移动通信有限公司 | Image sensor, camera module, terminal and imaging method |
| CN110995968B (en) * | 2019-11-25 | 2021-08-20 | Oppo广东移动通信有限公司 | Image sensor, image pickup apparatus, electronic device, and imaging method |
| CN111193880B (en) * | 2020-01-13 | 2022-05-24 | 刘元哲 | Image sensor, optical filter and image sensor brightness adjusting method |
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