CN100414590C - Display faceplate - Google Patents

Abstract

The present invention relates to a display panel suitable for an organic luminous display device which is provided with an input mode and a display mode. The display panel comprises a drive unit, a capacitor, a light emitting diode (LED), a light detection unit and a detection unit, wherein the drive unit is provided with a control electrode, a first electrode and a second electrode, wherein the control electrode is coupled to a first node; the first electrode is coupled to a first power supply. The capacitor is coupled to a position between the first node and the first power supply. The LED is coupled to a position between the second electrode of the drive unit and a second power supply. The light detection unit is coupled to a position between the first node and the first power supply. The detection unit is coupled to the first node and detects a voltage of the first node when the display device is in the input mode so as to generate an input signal.

Description

Display panel

Technical field

The present invention relates to a kind of display device, particularly a kind of display device, it has display mode and input pattern.

Background technology

The inputting interface of conventional personal computer or workstation can't reach the purpose of quick transmission and exchange message, its reason is that it is not to import with the sounding or the handwriting mode of human intuition, but must use keyboard or mouse to reach communication between people and the computing machine.Chance and speed continuous expansion along with information interchange, tradition can't satisfy the demand of snap information interchange already as the platform of information interchange with personal computer or workstation, so use the input mode of non-keyboard, non-mouse, will replace the old communication way of people and information equipment in a large number.The input method of non-keyboard, non-mouse type, developing proven technique at present is exactly the use of input panel.

Having the technical of input panel now, because amorphous silicon film transistor (amorphous siliconthin film transistor, a-Si TFT) leakage current is very sensitive to light, generally can form the inspection optical diode by a-Si TFT, with as image sensor.People such as the Jeong Hyun Kim of LG.Pilips company propose a kind of fingerprint scanner, it is the inspection optical diode that utilizes a-Si TFT to form, sensing is by the light that reflected of finger, again by sensor amplifier (readout amplifier) and then judge fingerprint.

In addition, the people such as T.Nakamura of Toshiba Matsushita Display more propose a kind of liquid crystal indicator with pick-up image function, it utilizes low temperature polycrystalline silicon (low temperaturepoly-silicon, LTPS) TFT is as optical sensor, its principle of operation is that backlight emits light into object by pixel cell, the LTSP TFT light that then sensing reflected, cause the stored charge loss of reservior capacitor in the pixel cell, and then detect object image.

Summary of the invention

Fundamental purpose of the present invention is to provide a kind of display panel, and (it has demonstration and input pattern for organiclight emitting display, OLED) device to be applicable to organic light emitting display.Display panel comprises driver element, capacitor, light emitting diode, inspection light unit and detecting unit.Driver element has the control electrode that couples first node, couples first electrode of first power supply, and second electrode.Capacitor is coupled between the first node and first power supply.Light emitting diode is coupled between second electrode and second source of driver element.Inspection light unit is coupled between the first node and first power supply.Detecting unit couples first node, when display device is input pattern, detect the voltage of first node, to produce input signal, this detecting unit comprises: a charge amplifying circuit couples this first node, and receives a reference voltage, in order to detecting the voltage of this first node, and produce a read-out voltage; And an analog/digital converter, according to this read-out voltage to produce this input signal.

When display device was display mode, driver element came the driven for emitting lights led lighting according to the voltage of first node.When display device is input pattern, lumination of light emitting diode, and inspection light unit senses makes the voltage of this first node change by the light that an object is reflected.

For above-mentioned purpose of the present invention, feature and advantage can be become apparent, a preferred embodiment cited below particularly, and conjunction with figs. are described in detail below.

Description of drawings

Fig. 1 represents the panel synoptic diagram of the OLED device of first embodiment of the invention.

Fig. 2 represents display unit and the detecting unit of first embodiment.

Fig. 3 illustrates the voltage v20 of node N20 and the relation of light intensity.

Fig. 4 represents an example of inspection light unit among first embodiment.

Fig. 5 represents another example of inspection light unit among first embodiment.

Fig. 6 is the display unit of expression second embodiment.

Fig. 7 is the display unit of expression the 3rd embodiment.

Symbol description

1～panel;

10～data driver;

11～scanner driver;

12～testing circuit;

13～array of display;

20～driver element;

21,22,60,70...72～switch element;

23～luminescence unit;

24～reservior capacitor;

25～inspection light unit;

100～display unit;

120～charge amplifying circuit;

121～analog/digital converter;

250～control module;

D ₁... D _m～data line;

DU ₁... DU _m～detecting unit;

L20～light emitting diode;

Cfb～capacitor;

P25～inspection optical diode;

S ₁... S _n～sweep trace;

SW12～switch;

T20...T22, T25, T250, T251, T60, T70...T71～transistor;

Vdd, Vss～power supply;

Vref～reference power source;

Embodiment

First embodiment:

Fig. 1 is organic light emitting display (organic light emittingdisplay, OLED) Zhuan Zhi the panel synoptic diagram of expression first embodiment of the invention.This OLED device has display mode and input pattern.Panel 1 comprises data driver 10, scanner driver 11, testing circuit 12 and array of display 13.The a plurality of data line D of data driver 10 controls ₁To D _m, and a plurality of sweep trace S of scanner driver 11 controls ₁To S _nTesting circuit 12 comprises a plurality of detecting unit DU ₁To DU _mArray of display 13 comprises a plurality of display units, and each staggered data line and display unit of sweep trace formation, for example, and data line D ₁With sweep trace S ₁Form display unit 100.In embodiments of the present invention, each data line couples a detecting unit, for instance, and data line D ₁Couple detecting unit DU ₁

Fig. 2 is the display unit 100 and detecting unit DU of expression first embodiment ₁As shown in the figure, the equivalent electrical circuit of display unit 100 (other display unit is also identical) is to comprise driver element 20, switch element 21 and 22, luminescence unit 23, reservior capacitor 24, inspection light unit 25.In the present embodiment, driver element 20 comprises P transistor npn npn T20.Switch element 21 and 22 is respectively P type T21 and N transistor npn npn T22.Luminescence unit 23 comprises light emitting diode (light-emitting diode, LED) L20.Inspection light unit 25 comprises inspection optical diode P25.

The grid of transistor T 20 (control electrode) couples node N20, and its drain electrode (first electrode) couples the drain electrode of transistor T 22, and its source electrode (second electrode) couples power supply Vdd.The grid of transistor T 21 couples sweep trace S ₁, its drain electrode couples data line D ₁, and its source electrode couples node N20.The grid of transistor T 22 couples sweep trace S ₁, its drain electrode couples the drain electrode of transistor T 20, and its source electrode couples LEDL20.Inspection optical diode P25 is coupled between power supply Vdd and the node N20, and reservior capacitor 24 is coupled between power supply Vdd and the node N20.LED L20 is coupled between the source electrode and power supply Vss of transistor T 22.Wherein, power supply Vdd and Vss provide the voltage vdd and the low level voltage vss of high level respectively.

Detecting unit DU ₁Comprise charge amplifying circuit 120 and analog/digital converter 121.The inverting input (-) of charge amplifier 120 couples data line D ₁, and its normal phase input end (+) couples reference power source Vref.Switch SW 12 and capacitor Cfb are parallel between the output terminal and inverting input of charge amplifier 120.Analog/digital converter 121 is coupled to the output terminal of charge amplifier 120.

When the OLED of present embodiment device was display mode, transistor T 21 and T22 were according to sweep trace S ₁On sweep signal and conducting and close data line D respectively ₁Data signal makes the voltage of node N20 equal the voltage vdata of data-signal to display unit 100, and at this moment, reservior capacitor 24 stored voltages equal (vdd-vdata).Then, transistor T 21 and T22 close respectively and conducting.Transistor T 20 is according to the data voltage vdata of node N20 and conducting, and produces drive current, and L20 is luminous with driving LED.

When the OLED of present embodiment device was input pattern, transistor T 21 and T22 were according to sweep trace S ₁On sweep signal and conducting and closing respectively.At first, the reference voltage vref that is provided according to the reference power source Vref of charge amplifying circuit 120 is by data line D ₁, make the voltage of node N20 be set at voltage vref.At this moment, the saturated charge in the reservior capacitor 24 is:

Q _sat＝cs*(vdd-vref)

Wherein, Q _SatBe the saturated charge in the reservior capacitor 24, cs is the capacitance of reservior capacitor 24.

Then, transistor T 21 and T22 close respectively and conducting, and transistor T 20 is luminous with driving LED L20 according to the voltage v20 (equaling voltage vref) of node N20.After light that LEDL20 launched ran into object as input tool, object was according to the GTG degree of itself, with light reflected back display unit 100 in various degree.Inspection optical diode P25 is the light that reflects of sensing then, and produce photocurrent (photo current) Iph and cause electric leakage.Therefore, the voltage v20 of node N20 is because the electric leakage of inspection optical diode P25, and increased towards voltage vdd by voltage vref.When the light that reflects is strong more, the electric leakage of inspection optical diode P25 is big more, and voltage v20 then equals voltage vdd when maximum.Fig. 3 is illustrated in the voltage v20 of node N20 in the frame (frame) and the relation of light intensity, and the light that the direction indication of the arrow A among the figure reflects grows from weak to strong.Detecting unit DU ₁120 of charge amplifying circuit the voltage v20 that is read is amplified and output read-out voltage vout:

$\mathrm{vout}=\frac{{\∫}_0^{0+\mathrm{Tf}}\mathrm{iph}\left(t\right)\mathrm{dt}}{\mathrm{cfb}}$

Wherein, iph represents the value of photocurrent Iph, and t0 represents readout time, and Tf represents a frame time, and cfb represents the value of capacitor Cfd.

Therefore, can obtain maximum read-out voltage voutmax according to saturated charge:

$\mathrm{vout}\max =\frac{\mathrm{cs}*(\mathrm{vdd}-\mathrm{vref})}{\mathrm{cfb}}$

Afterwards, the voltage vout that 120 of charge amplifying circuit are exported is through behind the analog/digital converter 121, and then corresponding digital input signals to the back-end device of output is handled or stored.Behind the corresponding input signal of analog/digital converter 121 outputs, switch SW 12 conductings of charge amplifying circuit 120 make the voltage V20 of node N20 reset to reference voltage vref to carry out the action of resetting.

The inspection optical diode P25 of present embodiment can realize by transistor T 25.Consult Fig. 4, the source electrode of transistor T 25 couples power supply Vdd, and its grid and drain electrode are electrically connected to each other in node N20.In addition, owing to when just thinking that the OLED device is input pattern, just need inspection light unit 25 come sensor light,, examine light unit 25 and can move according to a control signal SC in order to reduce the consumption of energy.Consult Fig. 5, inspection light unit 25 more comprises control module 250.Control module 250 comprises transistor T 250 and T251, and in the present embodiment, transistor T 250 and T251 are respectively P type and N transistor npn npn.The grid of transistor T 250 receives control signal SC, and its source electrode couples the grid of transistor T 25, and its drain electrode couples node N20.The grid of transistor T 251 receives control signal SC, and its drain electrode couples the grid of transistor T 25, and its source electrode couples power supply Vss.

Consult Fig. 5, when the OLED of present embodiment device is display mode, need not utilize inspection light unit 25 to come sensor light, thus control signal SC be high-voltage level with turn-on transistor T251 and close transistor T 250, make the grid of transistor T 25 couple the power supply Vss of low voltage level.Therefore transistor T 25 closes, and the sensor light action is not carried out in 25 of inspection light unit.When the OLED of present embodiment device is input pattern, then need to utilize inspection light unit 25 to come sensor light, therefore control signal be low voltage level with turn-on transistor T250 and close transistor T 251, make the grid of transistor T 25 and drain electrode electrically connect, to form the inspection optical diode.

In first embodiment, transistor T 25 can be low temperature polycrystalline silicon (low temperaturepoly-silicon, LTPS) thin film transistor (TFT).

Second embodiment:

Fig. 6 is the display unit 100 of expression second embodiment.As shown in the figure, the equivalent electrical circuit of display unit 100 (other display unit is also identical) is to comprise driver element 20, switch element 60, luminescence unit 23, reservior capacitor 24, inspection light unit 25.In the present embodiment, driver element 20 comprises P transistor npn npn T20.Switch element 60 is N transistor npn npn T60.Luminescence unit 23 comprises light emitting diode (light-emitting diode, LED) L20.Inspection light unit 25 comprises inspection optical diode P25.

The grid of transistor T 60 couples sweep trace S ₁, its drain electrode couples data line D ₁, and its source electrode couples node N20.The framework of inspection light unit 25 also can be shown in the 4th and 5 figure.

The 3rd embodiment:

Fig. 7 is the display unit 100 of expression the 3rd embodiment.As shown in the figure, the equivalent electrical circuit of display unit 100 (other display unit is also identical) is to comprise driver element 20, switch element 70 to 72, luminescence unit 23, reservior capacitor 24, inspection light unit 25.In the present embodiment, driver element 20 comprises P transistor npn npn T20.Switch element 71 is P transistor npn npn T71, and switch element 70 and 72 is respectively N transistor npn npn T70 and T72.Luminescence unit 23 comprises light emitting diode (light-emittingdiode, LED) L20.Inspection light unit 25 comprises inspection optical diode P25.

The grid of transistor T 70 couples sweep trace S ₁, its drain electrode couples data line D ₁, and its source electrode couples node N70.The grid of transistor T 71 couples node N20, and its source electrode couples node N70, and its drain electrode couples power supply Vdd.The grid of transistor T 72 couples removes sweep trace ES ₁, its drain electrode couples node N70, and its source electrode couples node N20.Wherein, in a frame, remove sweep trace ES ₁The sequential of last removing signal is different from sweep trace S ₁The sequential of last sweep signal, and the pulse of clear signal is the pulse that is connected in sweep signal.The framework of inspection light unit 25 also can be shown in the 4th and 5 figure.

According to embodiments of the invention, OLED device proposed by the invention has demonstration and input pattern.When being in display mode, display panel is then carried out as existing operation.When being in input pattern, but the inspection light unit sensing in each display unit is being judged input signal by the light that object reflected by testing circuit.Inspection light of the present invention unit can be realized by low temperature polycrystalline silicon (LTPS) thin film transistor (TFT).

Though the present invention discloses as above with preferred embodiment; so it is not in order to limit scope of the present invention; anyly have the knack of this skill person; without departing from the spirit and scope of the present invention; when can doing a little change and retouching, so protection scope of the present invention is as the criterion when looking accompanying the claim person of defining.

Claims (18)

1. a display panel is applicable to organic light-emitting display device, and this display device has an input pattern and a display mode, comprising:

One driver element has the control electrode that couples a first node, couples first electrode of one first power supply, and second electrode;

One capacitor is coupled between this first node and this first power supply;

One light emitting diode is coupled between second electrode and a second source of this driver element;

One inspection light unit is coupled between this first node and this first power supply; And

One detecting unit couples this first node, when this display device is this input pattern, detects the voltage of this first node, and to produce an input signal, this detecting unit comprises:

One charge amplifying circuit couples this first node, and receives a reference voltage, in order to detecting the voltage of this first node, and produces a read-out voltage; And

One analog/digital converter, according to this read-out voltage to produce this input signal.

2. display panel as claimed in claim 1,

Wherein, when this display device was this display mode, this driver element drove this lumination of light emitting diode according to the voltage of this first node; And

Wherein, when this display device is this input pattern, this lumination of light emitting diode, and this inspection light unit senses makes the voltage of this first node change by the light that an object is reflected.

3. display panel as claimed in claim 2, wherein, when this display device was this input pattern, the voltage of this first node was charged to a reference voltage earlier.

4. display panel as claimed in claim 1, wherein, when this display device is this input pattern, the voltage of this first node is charged to this reference voltage earlier, this driver element according to this reference voltage to drive this lumination of light emitting diode, and this inspection light unit senses makes the voltage of this first node change by the light that an object is reflected.

5. display panel as claimed in claim 1 more comprises:

One first switch element has the control electrode that couples the one scan line, couple first electrode of this first node, and second electrode couples a data line; And

One second switch unit has control electrode, couples first electrode of second electrode of this driver element, and second electrode that couples this light emitting diode.

6. display panel as claimed in claim 5, wherein, this first switch element is the transistor of one first kenel, and this second switch unit transistor that is one second kenel.

7. display panel as claimed in claim 1 more comprises: a switch element, have the control electrode that couples the one scan line, and couple first electrode of a data line, and second electrode that couples this first node.

8. display panel as claimed in claim 1 more comprises:

One first switch element has the control electrode that couples the one scan line, couples first electrode of a data line, and second electrode that couples a Section Point;

One second switch unit has the control electrode that couples this first node, couples first electrode of this Section Point, and second electrode that couples this first power supply; And

One the 3rd switch element has the control electrode that couples a removing sweep trace, couples first electrode of this first node, and second electrode that couples this Section Point.

9. display panel as claimed in claim 8, wherein, the transistor of this second switch unit one first kenel, and this first and the 3rd switch element is the transistor of second kenel.

10. display panel as claimed in claim 8, wherein, the signal sequence of this removing sweep trace is different from the signal sequence of this sweep trace.

11. display panel as claimed in claim 10, wherein, the signal pulse of this removing sweep trace is connected in the signal pulse of this sweep signal.

12. display panel as claimed in claim 1, wherein, this inspection light unit comprises a first transistor, and the source electrode of this first transistor couples this first power supply, and the grid of this first transistor and drain electrode are electrically connected to each other.

13. display panel as claimed in claim 12, wherein, this first transistor is a low-temperature polysilicon film transistor.

14. display panel as claimed in claim 1, wherein, this inspection light unit more comprises:

One the first transistor has grid, couples the drain electrode of this first node, and the source electrode that couples this first power supply;

Whether one control module according to this input and display mode, electrically connects with grid and the drain electrode of controlling this first transistor.

15. display panel as claimed in claim 14, wherein, this control module comprises:

One transistor seconds has the grid that receives a control signal, couples the drain electrode of this first node, and the source electrode that couples the grid of this first transistor; And

One the 3rd transistor has the grid that receives this control signal, couples the drain electrode of the grid of this first transistor, and the source electrode that couples this second source;

Wherein, when this display device was this display mode, the 3rd transistor was according to this control signal and conducting, so that the grid of this first transistor couples this second source; And

Wherein, when this display device was this input pattern, this transistor seconds was according to this control signal and conducting, so that the grid of this first transistor electrically connects with drain electrode.

16. display panel as claimed in claim 15, wherein, this transistor seconds is first kenel, and the 3rd transistor is second kenel.

17. display panel as claimed in claim 16, wherein, this first transistor is second kenel.

18. display panel as claimed in claim 14, wherein, this first transistor is a low-temperature polysilicon film transistor.

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