CN101266346B - Light sensitive element and LCD device applying same - Google Patents

Light sensitive element and LCD device applying same Download PDF

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Publication number
CN101266346B
CN101266346B CN200710086284A CN200710086284A CN101266346B CN 101266346 B CN101266346 B CN 101266346B CN 200710086284 A CN200710086284 A CN 200710086284A CN 200710086284 A CN200710086284 A CN 200710086284A CN 101266346 B CN101266346 B CN 101266346B
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film transistor
circuit
electrode
grid
electrically connected
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CN101266346A (en
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陈柏仰
施博盛
张祖强
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Hannstar Display Corp
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Hannstar Display Corp
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Abstract

A light-sensitive cell includes a switch thin-film transistor and an optical detection element. The gate electrode of the switch thin-film transistor is electrically connected to a switch circuit, and the source electrode of the switch thin-film transistor is electrically connected to a reading circuit. The optical detection element is coupled between the switch circuit and the drain electrode of the switch thin-film transistor, in order to detect the brightness of light on the optical detection element.

Description

Light activated element and use the LCD of this light activated element
Invention field
The present invention relates to a kind of light activated element, and be particularly related to a kind of light activated element and LCD with measuring ability.
Technical background
Trackpad generally has transparent surface, and is installed on the display device, for example mobile computer or personal digital assistant (personal digital assistant; PDA) on the LCD, to provide input interface or input media to the user, the work of importing, and devices such as keyboard that need not be extra or mouse.Trackpad also often is used in the work of drawing, for example is Drafting CADD etc.Trackpad is also usually with touch-control film (touch film), Touch Screen (touch screen), digiboard (digitizer), flat computer (tablet pc) or electrical patterns input panel (electric graphic input panel; EGIP) form occurs.
According to the difference of inducing method, Trackpad is divided into resistance-type, condenser type or electromagnetic type or the like usually.The Trackpad of resistance-type is to utilize electric current to change to detect touched position.Capacitive contact panel then is to utilize capacitance variations to detect touched position.The Trackpad of electromagnetic type then is that the variation of the resonant frequency by applying electromagnetic field and touched position detects touched position.
Multi-form Trackpad has the technology of multi-form signal amplification, resolution and signal Processing.Therefore, according to different demands, the user can select required display device and suitable Trackpad according to economically benefit, life of product, photoelectric property, the opering characteristic of electric apparatus, engineering properties, environmental testing and input characteristics or the like factor.
Yet the transparent surface that Trackpad has is installed between the surface of user and display (for example being LCD) visible area, has many shortcomings.For example, because the transparent surface of Trackpad is in conjunction with many optical thin films of liquid crystal panel itself, it will cause light to form repeatedly reflection, thereby reduce the contrast of display, and the generation phenomenon of dazzling light (glare).In addition, on display, add the production cost that Trackpad also increases display, and increase the complexity and the thickness of assembling.Therefore, in its thin film transistor (TFT) array substrate, to replace the transparent touch plate that is installed on display surface in addition, it can simplify the package program of the LCD with touch controllable function to LCD partly in conjunction with light activated element.
Shown in Figure 1A, current type light activated element 100 has photoconductive film transistor (photothin film transistor; Photo TFT) 110 and switching thin-film transistor (switch thinfilm transistor; Switch TFT) 130.The source electrode 136 of switching thin-film transistor 130 is electrically connected and reads circuit (readout line) 140, and 132 of its gate electrodes are electrically connected switching circuit (switch line) 150.Its drain electrode 134 then is electrically connected the source electrode 116 of photoconductive film transistor 110.In addition, gate electrode 112 and drain electrode 114 both all be electrically connected to bias voltage circuit (bias voltage line) 120.Bias voltage circuit 120 provides voltage to photoconductive film transistor 110.Therefore, after switching thin-film transistor 130 is unlocked, the photocurrent by photoconductive film transistor 110 will be affected because of photoconductive film transistor 110 lip-deep brightness.Generally speaking, this photocurrent will become positive correlation with photoconductive film transistor 110 detected brightness.Yet too much metallic circuit is configured on the substrate of thin film transistor (TFT) array, for example is to read circuit 140, switching circuit 150 and bias voltage circuit 120 it will obviously have influence on the aperture opening ratio (aperture ratio) of LCD.
Because the light activated element of current type 100 needs to connect three metallic traces, for example be switching circuit 150, bias voltage circuit 120 and read circuit 140, to drive the brightness that light activated element 100 measures the light on it.Therefore, the light activated element of current type generally is referred to as three end points light activated elements.Shown in Figure 1B, show the light activated element 800 of electric charge formula.Electric charge formula light activated element 800 comprises photoconductive film transistor (photo TFT) 850, switching thin-film transistor (switch TFT) 840 and electric capacity 860.The source electrode of switching thin-film transistor 840 is electrically connected and reads circuit 810, and utilizes its gate electrode to be electrically connected switching circuit 820.Its drain electrode then is electrically connected the source electrode of photoconductive film transistor 850.In addition, the gate electrode of photoconductive film transistor 850 all is electrically connected bias voltage circuit 830 with drain electrode.Notably be that this kind electric charge formula light activated element also is called as the light activated element of three end points formulas.Itself and current type light activated element 100 is also incomplete same, and electric charge formula light activated element 800 generally has extra element, electric capacity 860.
In the same manner, also necessary at least three metallic traces that connect of the light activated element 800 of electric charge formula for example are switching circuit 820, bias voltage circuit 830 and read circuit 810, to drive the brightness that light activated element 800 measures the light on it.
Therefore, can be because the configuration of too much metallic circuit (or lead) thereon, makes its aperture opening ratio thereby reduction in conjunction with light activated element in the LCD of thin film transistor (TFT) array substrate.How to improve the susceptibility of liquid crystal touch control panel and improve the performance that shows, by developing the target that the dealer is made great efforts.
Summary of the invention
According to aforementioned purpose, the invention provides a kind of light activated element, comprise at least: switching circuit (230); Read circuit (240); Switching thin-film transistor (210) has first grid electrode (212), first termination electrode (216) and second termination electrode (214), wherein, this first grid electrode (212) is electrically connected to this switching circuit (230), and this first termination electrode (216) is electrically connected to this and reads circuit (240); And photoconductive film transistor (220), have second grid electrode (222), three-end electrode (226) and the 4th termination electrode (224), wherein this second grid electrode (222) and the 4th termination electrode (224) are electrically connected to this switching circuit (230), and second termination electrode (214) of this switching thin-film transistor (210) is electrically connected with the three-end electrode (226) of this photoconductive film transistor (220).
Another aspect of the present invention provides a kind of light activated element, comprises at least: switching circuit (630); Read circuit (640); The common circuit of LCD or grid circuit (650); Switching thin-film transistor (610) has first grid electrode (612), first termination electrode (616) and second termination electrode (614), wherein, this first grid electrode (612) is electrically connected to this switching circuit (630), and this first termination electrode (616) is electrically connected to this and reads circuit (640); And photoconductive film transistor (620), have second grid electrode (622), three-end electrode (626) and the 4th termination electrode (624), wherein this second grid electrode (622) is electrically connected to this switching circuit (630), the 4th termination electrode (624) is electrically connected to the common circuit and the grid circuit (650) of this LCD, and second termination electrode (614) of this switching thin-film transistor (610) is electrically connected with the three-end electrode (626) of this photoconductive film transistor (620).
Another aspect of the present invention provides a kind of light activated element, comprises at least: switching circuit (730); Read circuit (740); The common circuit of LCD or grid circuit (750); Switching thin-film transistor (710) has first grid electrode (712), first termination electrode (716) and second termination electrode (714), wherein, this first grid electrode (712) is electrically connected to this switching circuit (730), and this first termination electrode (716) is electrically connected to this and reads circuit (740); And photoconductive film transistor (720), have second grid electrode (722), three-end electrode (726) and the 4th termination electrode (724), wherein this second grid electrode (722) is electrically connected to the common circuit or the grid circuit (750) of this LCD, the 4th termination electrode (724) is electrically connected to this switching circuit (730), and second termination electrode (714) of this switching thin-film transistor (710) is electrically connected with the three-end electrode (726) of this photoconductive film transistor (720).
Another aspect of the present invention also provides a kind of read pixel, is used for LCD, and this read pixel comprises: pixel thin film transistor (450,450a, 550A) is disposed at the substrate of this LCD; Be disposed at this substrate according to the described light activated element of the invention described above either side.
Another aspect of the present invention provides a kind of LCD.This LCD includes colored filter substrate, thin film transistor (TFT) array substrate and liquid crystal layer and is located between colored filter substrate and the thin film transistor (TFT) array substrate.In addition, a plurality of grid circuits, data circuit, read circuit and read pixel is formed on this thin film transistor (TFT) array substrate.Each read pixel more includes above-mentioned pixel thin film transistor and above-mentioned light activated element.And switching thin-film transistor wherein, pixel thin film transistor and light activated element preferably can be made of amorphous silicon film transistor.
Description of drawings
For above and other objects of the present invention, feature, advantage and embodiment can be become apparent, appended graphic being described in detail as follows:
Figure 1A shows the current type light activated element of known LCD;
Figure 1B shows the electric charge formula light activated element of known LCD;
Fig. 2 shows the synoptic diagram of first preferred embodiment of light activated element of the present invention;
Fig. 3 shows the current measurement curve map of first preferred embodiment under varying environment of Fig. 2;
First preferred embodiment that Fig. 4 A shows Fig. 2 is applied to the schematic circuit diagram of read pixel;
First preferred embodiment that Fig. 4 B shows Fig. 2 is applied to the schematic circuit diagram of another read pixel;
First preferred embodiment that Fig. 5 A shows Fig. 2 is applied to the schematic circuit diagram of another read pixel;
Fig. 5 B shows the normal pixel synoptic diagram of LCD;
Fig. 6 shows the synoptic diagram of second preferred embodiment of light activated element of the present invention; And
Fig. 7 shows the synoptic diagram of the 3rd preferred embodiment of light activated element of the present invention.
Embodiment
Below will and describe in detail and clearly demonstrate embodiments of the invention with diagram, as the person skilled in the art after understanding preferred embodiment of the present invention, when can be by the technology of teachings of the present invention, change and modification, so it does not break away from the present invention's spirit and scope.
Consult Fig. 2, it shows the synoptic diagram of first preferred embodiment of light activated element of the present invention.Light activated element 200 includes switching thin-film transistor (switch TFT) 210 and photoconductive film transistor (photo TFT) 220.Each above-mentioned thin film transistor (TFT) includes a gate electrode and two termination electrode (terminal electrode, also be referred to as source/drain electrode), and above-mentioned thin film transistor (TFT) is coupled between two conducting wires, for example is switching circuit (switch line) 230 and reads circuit (readout line) 240.The gate electrode 212 of switching thin-film transistor 210 connects switching circuit 230, and the gate electrode 222 of photoconductive film transistor 220 also is connected in this switching circuit 230 with drain electrode 224.The drain electrode 214 of switching thin-film transistor 210 connects the source electrode 226 of photoconductive film transistor 220.In addition, circuit 240 is read in 216 connections of the source electrode of switching thin-film transistor 210.
Compare the known light activated element 100 among light activated element 200 and Figure 1A, light activated element 200 can be incorporated into the bias voltage circuit among the switching circuit 230, and need not additionally connect the bias voltage circuit.So the quantity of the metallic circuit in thin film transistor (TFT) array substrate can be lowered effectively.Light activated element 200 also only need be connected to switching circuit 230 and read 240 in circuit.The thin film transistor (TFT) array substrate of LCD bias voltage circuit independently in one embodiment of the invention hereat, its light activated element 200 only need be connected to two metallic circuits.
Table one: photocurrent measuring value
W/L=48/5 V D=V G=5V V D=V G=10V V D=V G=15V
Dark 2.34E-08 9.38E-07 3.6E-06
Bright 3.98E-07 2.43E-06 6.6E-06
I bright-I dark 3.75E-07 1.49E-06 3.01E-06
Unit: ampere (A)
V wherein DBe the measurement voltage of the brilliant drain electrode of photo-conductive film electricity, and V GBe the measurement voltage of photoconductive film transistor gate electrode, the about 2150cd/m2 of ambient brightness under the bright situation, next in the dark situation is to be placed in the black box, measures to get rid of other external light source.
In addition, table one is the measuring value of the photocurrent that measured on the light activated element 200.Wherein the measuring value of photocurrent is under the situation of bright, is to be about under the situation of 2150cd/m2 with ambient brightness to carry out, and the situation of dark, then is it is positioned among the box of black, carries out under the situation with the light source of isolating other.Consult table one, under the situation of VG and VD increase, the difference of photocurrent also increases simultaneously.Because the gate electrode 222 and the drain electrode 224 of photoconductive film transistor 220 are connected to switching circuit 230 simultaneously, therefore, compared to the bias voltage of known light activated element 100, switching circuit 230 of the present invention can provide higher voltage to photoconductive film transistor 220.So the difference of the also more known light activated element 100 of difference of the photocurrent under bright and the dark situation is big.
Consult Fig. 3, show the current measurement curve under the varying environment of first preferred embodiment among Fig. 2.Wherein Z-axis represents that the measuring value unit of photocurrent is ampere (Ampere; A), transverse axis is then represented the voltage difference of the source electrode and the drain electrode of switching thin-film transistor.Curve 310 is drain current curves that switching thin-film transistor is measured under the situation of dark.320 of curves are the load curve of photoconductive film transistor under the dark situation.In addition, 330 of curves are the load curve of photoconductive film transistor under the bright situation.Metric data among Fig. 3 is further put in order and is exposed in the table two.Table two is the photoconductive film transistor of light activated element 200 of the present invention and the magnitude of current measured value of photoconductive film transistor+switching thin-film transistor.
Table two: the magnitude of current measured value of photoconductive film transistor and photoconductive film transistor+switching thin-film transistor
W/L=48/5 Photo TFT Photo TFT+Switch TFT
Dark 2.17E-06 8.28E-07
Bright 2.93E-06 9.85E-07
I bright-I dark 7.64E-07 1.57E-07
Unit: ampere (A)
V wherein DBe the measurement voltage of the brilliant drain electrode of photo-conductive film electricity, and V GBe the measurement voltage of photoconductive film transistor gate electrode, the about 2150cd/m2 of ambient brightness under the bright situation, next in the dark situation is to be placed in the black box, measures to get rid of other external light source.
In addition, table three item is the TFT photoconductive film transistor of known light activated element 100 and the magnitude of current measured value of photoconductive film transistor+switching thin-film transistor.
Table three: the magnitude of current measured value of known photoconductive film transistor and photoconductive film transistor+switching thin-film transistor
Photo TFT Photo TFT+Switch TFT
Dark 1.12E-09 1.10E-09
Bright 2.56E-08 2.41E-08
I bright-I dark 2.45E-08 2.30E-08
Unit: ampere (A)
V wherein DBe the measurement voltage of the brilliant drain electrode of photo-conductive film electricity, and V GBe the measurement voltage of photoconductive film transistor gate electrode, the about 2150cd/m2 of ambient brightness under the bright situation, next in the dark situation is to be placed in the black box, measures to get rid of other external light source.
Further comparison sheet two and table three, wherein, the electric current difference that under bright and dark environment, is measured, I Bright-I Dark, the first power of the more known electric current difference big approximately 10 of electric current difference of the present invention doubly.Therefore, the electric current difference of light activated element 200 can easier be read circuit 240 and detects.
In addition, light activated element of the present invention can be incorporated into each general pixel or general pixel partly, to form read pixel (readout pixel), therefore make liquid crystal device panel to provide and touch and the function that reads, also be referred to as in-building type contact panel (In-cell touchpanel).The quantity of required built-in light activated element then is decided by the required resolution of touch controllable function of in-building type contact panel.
Further consult Fig. 4 A, its first preferred embodiment that shows Fig. 2 is applied to the schematic circuit diagram of read pixel.Wherein, read pixel is configured in the thin film transistor (TFT) array substrate (TFT substrate) of LCD.Generally speaking, thin film transistor (TFT) array substrate include a plurality of grid circuits and the plurality of data circuit formed thereon.And these grid circuits and data circuit have defined a plurality of pixels jointly.For simplifying and clearly describe read pixel of the present invention, Fig. 4 A only illustrate single read pixel its respectively in conjunction with grid circuit 420 and data circuit 410, and omit general pixel (pixel that does not comprise light activated element).Read pixel includes pixel thin film transistor 450 and light activated element 400.Use pixel thin film transistor 450 to be used as on-off element, with the required electric charge of control liquid crystal display pixel.The drain electrode of the pixel thin film transistor 450 of this LCD and gate electrode then are connected to data circuit 410 and grid circuit 420 respectively.Light activated element 400 then includes photoconductive film transistor 430 and switching thin-film transistor 435, and it is coupled to grid circuit 421 and reads between the circuit 440.So read pixel of the present invention can utilize extra bias voltage circuit,, photoconductive film transistor 430 and switching thin-film transistor 435 produce the required voltage of photocurrent so that being provided.Therefore, utilize its aperture opening ratio of LCD with read pixel of the present invention to be enhanced effectively.In addition, as previously mentioned, because photocurrent difference of the present invention be greatly compared to the photocurrent difference of known light activated element, therefore, its photocurrent difference also can more easily be read circuit and measure, so therefore the size of light activated element of the present invention also can further be lowered.And, utilize the polyphone connected mode also can therefore reduce with the quantity of increase to the photoconductive film transistor of light change sensitivity.
Consult the schematic circuit diagram that first preferred embodiment that Fig. 4 B shows Fig. 2 is applied to another read pixel.The read pixel of Fig. 4 B is similar to the read pixel of Fig. 4 A, also includes pixel thin film transistor 450a and light activated element 400a.Yet this light activated element 400a is connected in grid circuit 420a and reads between the circuit 440a, and wherein the gate electrode of pixel thin film transistor 450a also is connected in grid circuit 420a.Therefore, by among above-mentioned Fig. 4 A and Fig. 4 B as can be known, pixel thin film transistor of the present invention can be linked to identical grid circuit or different grid circuits with light activated element, all can measure the variation of light luminance effectively.
First preferred embodiment that Fig. 5 A shows Fig. 2 is applied to the schematic circuit diagram of another read pixel, Fig. 5 B then show this LCD the normal pixel synoptic diagram its do not have light activated element.Generally speaking, the LCD with touch controllable function has comprised read pixel and general pixel, and wherein read pixel has light activated element, and general pixel does not then possess light activated element is arranged.Known light activated element utilizes common circuit as the bias voltage circuit usually, to provide photoconductive film transistor required voltage.Yet, between the source electrode that reads circuit and pixel thin film transistor, will therefore produce electric capacity (Cps; Not shown).So therefore the storage capacitors (Cst) of general pixel will must be increased, with extra electric capacity (Cps) in the compensation read pixel.It will cause the aperture opening ratio of the LCD with light activated element therefore to be limited.
Use the LCD with read pixel of first preferred embodiment of the present invention, the storage capacitors of its read pixel (Cst) 552A can be configured in the source electrode of pixel thin film transistor 550A and read between the circuit 540, is reading circuit (Cston readout line) so also can be referred to as Cst.In addition, storage capacitors (Cst) 552B of general pixel then can be configured between the source electrode and grid circuit 521 of pixel thin film transistor 550B, so also can be referred to as Cst at grid circuit (Cst on gate line).Therefore, the LCD with read pixel of the present invention can be effectively with common circuit by removing on the thin film transistor (TFT) array substrate.So the aperture opening ratio with LCD of read pixel of the present invention can be raised effectively.
Consult Fig. 6, show the synoptic diagram of second preferred embodiment of light activated element of the present invention.This light activated element 600 includes switching thin-film transistor 610 and photoconductive film transistor 620.Wherein, the source electrode 616 of switching thin-film transistor 610 is connected to and reads circuit 640, and the gate electrode 612 of switching thin-film transistor 610 then is connected to switching circuit 630.The drain electrode 614 of switching thin-film transistor 610 is connected to the source electrode 626 of photoconductive film transistor 620.622 of the gate electrodes of photoconductive film transistor 620 are connected to switching circuit 630, and the drain electrode 624 of photoconductive film transistor 620 is connected to conducting wire 650.When light activated element 600 be used in partly or the pixel of whole LCD among the time, switching circuit 630 can utilize the grid circuit of LCD, conducting wire 650 then can utilize the common circuit or the gate pole circuit of LCD.Table four is the magnitude of current measured value of photoconductive film transistor for this reason.
Table four: the magnitude of current measured value of photoconductive film transistor
W/L=48/5;V D=5V V G=5V V G=10V V G=15V
Dark 2.34E-08 7.88E-07 2.31E-06
Bright 3.98E-07 1.85E-06 3.71E-06
I bright-I dark 3.75E-07 1.07E-06 1.4E-06
Unit: ampere (A)
V wherein DBe the measurement voltage of the brilliant drain electrode of photo-conductive film electricity, and V GBe the measurement voltage of photoconductive film transistor gate electrode, the about 2150cd/m2 of ambient brightness under the bright situation, next in the dark situation is to be placed in the black box, measures to get rid of other external light source.
Its electric current difference (I Bright-I Dark) then the gate electrode 622 because of photoconductive film transistor 620 be connected to switching circuit 630, that is with respect to the driving voltage of the light activated element 100 of known LCD, it can provide the VG higher voltage usually; Hereat, electric current difference (I Bright-I Dark) will therefore increase, and be easy to read the measurement of circuit 640.
Consult Fig. 7, show the synoptic diagram of the 3rd preferred embodiment of light activated element of the present invention.This light activated element 700 includes switching thin-film transistor 710 and photoconductive film transistor 720.The source electrode 716 of switching thin-film transistor 710 is connected to and reads circuit 740, and the gate electrode 712 of switching thin-film transistor 710 then is connected to switching circuit 730.The drain electrode 714 of switching thin-film transistor 710 is connected to the source electrode 726 of photoconductive film transistor 720.The gate electrode 722 of photoconductive film transistor 720 is connected to conducting wire 750, and the drain electrode 724 of photoconductive film transistor 720 then connects switching circuit 730.When light activated element 700 is applied to the part of LCD or all in the pixel time, switching circuit 730 can utilize the grid circuit of LCD, conducting wire 750 then can utilize the common circuit or the gate pole circuit of LCD.Table five is magnitude of current measured values of this photoconductive film transistor.
Table five: the magnitude of current measured value of photoconductive film transistor
W/L=48/5;V G=5 V D=5V V D=10V V D=15V
Dark 2.34E-08 2.81E-08 3.26E-08
Bright 3.98E-07 4.72E-07 5.06E-07
I bright-I dark 3.75E-07 4.44E-07 4.74E-07
Unit: ampere (A)
Wherein VD is the measurement voltage of the brilliant drain electrode of photo-conductive film electricity, and VG is the measurement voltage of photoconductive film transistor gate electrode, the about 2150cd/m2 of ambient brightness under the bright situation, next in the dark situation is to be placed in the black box, measures to get rid of other external light source.
Its electric current difference (I Bright-I Dark) similarly also be enhanced, the drain electrode 724 of its photoconductive film transistor 720 is connected in switching circuit 730 so the drain electrode 724 of higher voltage to photoconductive film transistor 720 can be provided, for the voltage of known driving light activated element 100.Therefore, its electric current difference can be exaggerated and be easy to be read circuit 740 and measures.
Pixel thin film transistor of the present invention, switching thin-film transistor and photoconductive film transistor preferably can be made of amorphous silicon film transistor (amorphous silicon transistor).Because amorphous silicon film transistor is for irradiation light sensitive thereon, therefore, photoconductive film transistor of the present invention can be formed on the thin film transistor (TFT) array substrate, and detects the situation of the brightness change of irradiation light thereon, that is to say the relative different value of the light luminance on it.This photoconductive film transistor can also be a photodiode, and it can respond to irradiation light luminance thereon, and is connected between switching thin-film transistor and the switching circuit.That is to say that this light activated element can be constituted by switching thin-film transistor and photodiode.Or this photoconductive film transistor can be replaced by photoresistance, and this photoresistance can be responded to irradiation light luminance thereon, and is connected between switching thin-film transistor and the switching circuit.Therefore, this light activated element can be made of switching thin-film transistor and photoresistance.Hereat, light activated element can be made of switching thin-film transistor and photodetector, this photodetector can be for example photoconductive film transistor, photodiode or photoresistance, the size of the electric current of this light activated element controllable flow of while on it, therefore, the LCD with read pixel can utilize light activated element of the present invention to measure irradiation light difference thereon.
Light activated element of the present invention not only can be disposed at and read between circuit and the switching circuit, to simplify the complicacy of the required circuit of light activated element effectively, and can effectively increase the electric current difference, so that measure the difference of irradiation light luminance thereon, can also increase the aperture opening ratio of LCD simultaneously with read pixel.Light activated element of the present invention can also utilize switching circuit to provide higher voltage on the gate electrode or drain electrode of photoconductive film transistor, to increase the electric current difference, the convenient difference that measures irradiation light luminance thereon.Therefore, photoconductive film transistor of the present invention can increase the difference of electric current effectively, to be easy to measure the difference of the light luminance on it.And two termination electrodes of above-mentioned switching thin-film transistor or photoconductive film transistor, source electrode and drain electrode have interchangeability, and above-mentioned explanation only conveniently is used for clearly demonstrating its structure and syntagmatic, but not is used for limiting its scope.
As the personnel that are familiar with this technology understand, and the above is preferred embodiment of the present invention only, is not in order to limit claim of the present invention.All other do not break away from the equivalence of being finished under the disclosed spirit and changes or modification, all should be included in the following claim.

Claims (10)

1. light activated element comprises at least:
Switching circuit (230);
Read circuit (240);
Switching thin-film transistor (210) has first grid electrode (212), first termination electrode (216) and second termination electrode (214), wherein, this first grid electrode (212) is electrically connected to this switching circuit (230), and this first termination electrode (216) is electrically connected to this and reads circuit (240); And
Photoconductive film transistor (220), have second grid electrode (222), three-end electrode (226) and the 4th termination electrode (224), wherein this second grid electrode (222) and the 4th termination electrode (224) are electrically connected to this switching circuit (230), and second termination electrode (214) of this switching thin-film transistor (210) is electrically connected with the three-end electrode (226) of this photoconductive film transistor (220).
2. light activated element as claimed in claim 1, wherein this light activated element is disposed at substrate.
3. light activated element as claimed in claim 2, wherein this substrate is the thin film transistor (TFT) array substrate of LCD.
4. light activated element as claimed in claim 1, wherein this photoconductive film transistor and this switching thin-film transistor all are amorphous silicon membrane transistors.
5. light activated element comprises at least:
Switching circuit (630);
Read circuit (640);
The common circuit of LCD or grid circuit (650);
Switching thin-film transistor (610) has first grid electrode (612), first termination electrode (616) and second termination electrode (614), wherein, this first grid electrode (612) is electrically connected to this switching circuit (630), and this first termination electrode (616) is electrically connected to this and reads circuit (640); And
Photoconductive film transistor (620), have second grid electrode (622), three-end electrode (626) and the 4th termination electrode (624), wherein this second grid electrode (622) is electrically connected to this switching circuit (630), the 4th termination electrode (624) is electrically connected to the common circuit and the grid circuit (650) of this LCD, and second termination electrode (614) of this switching thin-film transistor (610) is electrically connected with the three-end electrode (626) of this photoconductive film transistor (620).
6. light activated element comprises at least:
Switching circuit (730);
Read circuit (740);
The common circuit of LCD or grid circuit (750);
Switching thin-film transistor (710) has first grid electrode (712), first termination electrode (716) and second termination electrode (714), wherein, this first grid electrode (712) is electrically connected to this switching circuit (730), and this first termination electrode (716) is electrically connected to this and reads circuit (740); And
Photoconductive film transistor (720), have second grid electrode (722), three-end electrode (726) and the 4th termination electrode (724), wherein this second grid electrode (722) is electrically connected to the common circuit or the grid circuit (750) of this LCD, the 4th termination electrode (724) is electrically connected to this switching circuit (730), and second termination electrode (714) of this switching thin-film transistor (710) is electrically connected with the three-end electrode (726) of this photoconductive film transistor (720).
7. a read pixel is used for LCD, and this read pixel comprises:
Pixel thin film transistor (450,450a, 550A) is disposed at the substrate of this LCD;
Be disposed at this substrate according to each described light activated element among the claim 1-6.
8. read pixel as claimed in claim 7, wherein pixel thin film transistor (450,550A) comprises that the 3rd gate electrode is electrically connected to the first grid circuit of this substrate (420,520), and switching circuit (421) is the second grid circuit of this substrate, and is adjacent to this first grid circuit (420,520).
9. read pixel as claimed in claim 7, wherein pixel thin film transistor (450a) comprises that the 3rd gate electrode is electrically connected to switching circuit (420a), and switching circuit (420a) is the grid circuit of this substrate.
10. a read pixel is used for LCD, and this read pixel comprises:
Pixel thin film transistor (550A) is disposed at the substrate of this LCD;
Be disposed at this substrate according to each described light activated element among the claim 1-6, wherein this pixel thin film transistor (550A) comprises that the 3rd gate electrode is electrically connected to the first grid circuit (520) of this substrate, and switching circuit is the second grid circuit of this substrate, and is adjacent to this first grid circuit (520); And
Storage capacitors (552A), the one electrode tip is electrically connected the five terminal electrode of this pixel thin film transistor, and circuit (540) is read in another electrode tip electrical connection of this storage capacitors (552A).
CN200710086284A 2007-03-13 2007-03-13 Light sensitive element and LCD device applying same Active CN101266346B (en)

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