CN201638531U - Pixel circuit of organic light-emitting display device - Google Patents

Abstract

The utility model relates to a pixel circuit of an organic light-emitting display device, which is respectively connected with a data line DATA, a scanning line SCAN, a power supply line VDD and an organic electroluminescent diode D1, wherein the data line DATA is used for transmitting data signals; the scanning line SCAN is used for transmitting scanning-selecting signals; the power supply line VDD is used for driving a power supply; and the organic electroluminescent diode D1 emits light according to the corresponding scanning-selecting signals. The pixel circuit comprises a switch transistor T1, a transistor T2 and a capacitor C1. The utility model has the beneficial effects that the pixel circuit adopts the single pixel wiring of the circuit structure, and after the scanning line SCAN and the power supply line VDD thereof are collinear, leads thereof are integrated together, thus reducing the occupied physical area due to the single arrangement of the VDD leads, and very obviously improving the aperture ratio of pixel; and therefore, the service life and reliability of an organic electric light-emitting device also can be improved, and the cost of the device is reduced.

Description

A kind of image element circuit of organic light emitting display

Technical field

The utility model belongs to display technique field, plane, especially belongs to the image element circuit of a kind of organic light emitting display (Organic Light-Emitting Display).

Background technology

Usually, organic light emitting display is to be combined according to matrix structure by N * M light emitting pixel unit, and each light emitting pixel unit all comprises an Organic Light Emitting Diode (Organic Light-EmittingDiode) and a corresponding image element circuit.As shown in Figure 1, existing image element circuit mainly is made up of two transistors and an electric capacity, wherein, the grid of switching transistor T1 is connected with data line DATA (data-signal DATA) with sweep trace SCAN (signal SCAN is selected in scanning) respectively with source electrode, and the drain electrode of switching transistor T1 is connected with the grid of transistor T 2; The drain electrode of transistor T 2 is connected with power lead VDD (power supply signal VDD), thereby source electrode is connected with organic electroluminescent LED D1 and is provided for the luminous electric current of D1; Capacitor C1 is connected between the source electrode of transistor T 2 and the grid and is used for keeping in the given time the voltage that transistor T 2 is applied.The operational process of the image element circuit of said structure is: when switching transistor T1 selects signal SCAN to be switched on according to the scanning that puts on its grid, data-signal DATA is applied on the grid and capacitor C1 of transistor T 2, the electric current that is complementary with data-signal DATA is stored among the capacitor C1, when transistor T 2 is switched on, is stored in electric current among the capacitor C1 and is released the organic electroluminescent LED D1 and make it luminous of flowing through.

When carrying out actual device wire according to the structure of existing image element circuit, as shown in Figure 2, with single light emitting pixel unit is example, sweep trace SCAN, data line DATA and power lead VDD, all to occupy the physical space of light emitting pixel unit, the ratio that makes the luminescence unit area account for total elemental area reduces, having dwindled the light-emitting area of each pixel cell, is exactly that brightness is not enough on the subjective effect.Aperture opening ratio promptly is that unit picture element unit actual carries out the ratio that luminous area contrasts all areas.In this kind device wire structure, the area of each about 20% ratio in light emitting pixel unit that power lead VDD occupies; In addition, thin film transistor (TFT) (TFT), signal wire (signal line, as data line DATA, sweep trace SCAN etc.) and indium tin oxide target electrode (ITO) when the wiring of the pixel cell of reality, it is the physical space that will occupy device, therefore, can clearly find out, adopt the aperture opening ratio inevitable lower (being about 34%) of the light emitting pixel unit of existing image element circuit, that is to say in whole pixel cell, real luminous component only accounts for the 1/3 more of whole pixel cell area, and this is a very low value.Under the little situation of aperture opening ratio, in order to reach corresponding luminosity, the strength of current that then is input to each light emitting pixel unit just must strengthen, the consequence of bringing is exactly that the power consumption of device sharply increases, simultaneously, owing to the increase of electric current and power consumption, also reduced the serviceable life and the luminescent quality of device light emitting pixel unit.

The utility model content

At the above-mentioned deficiency of prior art, the utility model provides a kind of image element circuit of organic light emitting display, can improve the aperture opening ratio of pixel cell, thereby when improving the brightness of display device and life-span, reduces device power consumption.

To achieve these goals, the utility model has adopted following technical scheme:

A kind of image element circuit of organic light emitting display, respectively with the data line DATA that is used for transmission of data signals, be used to transmit the sweep trace SCAN that signal is selected in scanning, be used to provide the power lead VDD of driving power, be used for selecting signal and luminous organic electroluminescent LED D1 connection according to the scanning of correspondence; Described image element circuit comprises:

Switching transistor T1, have grid that is connected with power lead VDD with the sweep trace SCAN of conllinear and the source electrode that is connected with data line DATA, be used to receive the signal that the sweep trace SCAN of conllinear and power lead VDD and data line DATA send and come the electric current of oxide-semiconductor control transistors T2 to flow;

Transistor T 2 has the drain electrode that is connected with power lead VDD with the sweep trace SCAN of conllinear, with switching transistor T1 drain electrode grid that is connected and the source electrode that is connected with organic electroluminescent LED D1, is used to provide organic electroluminescent LED D1 luminous electric current;

Capacitor C1 is connected between the earth terminal of the grid of transistor T 2 and organic electroluminescent LED D1, is used for keeping in the given time the voltage that transistor T 2 is applied.

The beneficial effects of the utility model are: the single pixel wiring that adopts circuit structure of the present utility model, its lead-in wire combines behind its sweep trace SCAN and the power lead VDD conllinear, thereby reduced shared physical area because the VDD lead-in wire is arranged separately, rule of thumb, this area accounts for about 20% of whole pixel cell area.This shows that the wiring of this kind circuit form is brought up to the aperture opening ratio that directly makes unit pixel more than 50% from original about 34%, has very significantly improved pixel aperture ratio.Thus, under the constant condition of device brightness, can significantly reduce and be used to drive the luminous strength of current of D1, reduce the power consumption of device, the inevitable raising that also can bring organic electro-luminescence device lifetime and reliability reduces device cost.

Description of drawings

Fig. 1 is the circuit theory diagrams of the image element circuit of existing light emitting pixel unit.

Fig. 2 is the device wire synoptic diagram of existing light emitting pixel unit.

Fig. 3 is the circuit theory diagrams of the image element circuit of light emitting pixel of the present utility model unit.

Fig. 4 is the device wire synoptic diagram of light emitting pixel of the present utility model unit.

Fig. 5 is the oscillogram that signal is selected in the scanning of the image element circuit of light emitting pixel of the present utility model unit.

Embodiment

The utility model is described in further detail below in conjunction with the drawings and specific embodiments.

As shown in Figure 3, a kind of image element circuit of organic light emitting display, respectively with the data line DATA that is used for transmission of data signals, be used to transmit the sweep trace SCAN that signal is selected in scanning, be used to provide the power lead VDD of driving power, be used for selecting signal and luminous organic electroluminescent LED D1 connection according to the scanning of correspondence; Described image element circuit comprises: switching transistor T1, have grid that is connected with power lead VDD with the sweep trace SCAN of conllinear and the source electrode that is connected with data line DATA, be used to receive the signal that the sweep trace SCAN of conllinear and power lead VDD and data line DATA send and come the electric current of oxide-semiconductor control transistors T2 to flow.Transistor T 2 has the drain electrode that is connected with power lead VDD with the sweep trace SCAN of conllinear, with switching transistor T1 drain electrode grid that is connected and the source electrode that is connected with organic electroluminescent LED D1, is used to provide organic electroluminescent LED D1 luminous electric current.Capacitor C1 is connected between the earth terminal of the grid of transistor T 2 and organic electroluminescent LED D1, is used for keeping in the given time the voltage of the control signal DATA that transistor T 2 is applied.

The course of work below in conjunction with the image element circuit of the above-mentioned specific embodiment of description of drawings: select under the effect of signal in scanning as shown in Figure 5, pixel circuit is according to following works: the phase one, when signal is selected in the scanning of the input end of the sweep trace SCAN of conllinear and power lead VDD to the grid input low level signal (signal SCAN is selected in scanning) of switching transistor T1, transistor T 1 conducting, the data-signal DATA that is applied to the T1 source electrode so will be transferred to the drain electrode of T1 smoothly, and be applied on the grid and capacitor C1 of transistor T 2, data-signal DATA is stored on the C1 the most at last, the drain electrode of transistor T 2 at this moment is owing to be changed to low level equally, to not have electric current and flow to organic electroluminescent LED D1 by T2, therefore, D1 is not luminous.Afterwards, in subordinate phase, when the scanning of the input end of the sweep trace SCAN of conllinear and power lead VDD selects signal to become high level signal (power supply signal VDD) from low level signal, switching transistor T1 ends, data-signal DATA no longer transmits to T2 by T1, and the switching transistor T1 that the data-signal DATA of the last pre-stored of C1 and the data-signal DATA of T1 source electrode have been ended keeps apart.Simultaneously, the level of power supply signal VDD will be applied to the drain electrode of transistor T 2, with being stored among the C1 in advance and being applied to the data-signal DATA of transistor T 2 grids, oxide-semiconductor control transistors T2 conducting, make to be subjected to the electric current of data-signal DATA control to enter organic electroluminescent LED D1, thereby it is luminous to drive D1 by transistor T 2.

In the described scheme of above-mentioned specific embodiment, as shown in Figure 4, in the device wire synoptic diagram of single pixel, its lead-in wire combines behind its sweep trace SCAN and the power lead VDD conllinear, thereby reduced shared physical area because the VDD lead-in wire is arranged separately, rule of thumb, this area accounts for about 20% of whole pixel cell area.This shows that the wiring of this kind circuit form is brought up to the aperture opening ratio that directly makes unit pixel more than 50% from original about 34%, has very significantly improved pixel aperture ratio.

Those of ordinary skill in the art will appreciate that embodiment described here is in order to help reader understanding's principle of the present utility model, should to be understood that protection domain of the present utility model is not limited to such special statement and embodiment.Everyly make various possible being equal to according to foregoing description and replace or change, all be considered to belong to the protection domain of claim of the present utility model.

Claims (1)

1. the image element circuit of an organic light emitting display, described image element circuit respectively and be used for the data line DATA of transmission of data signals, be used to transmit the sweep trace SCAN that signal is selected in scanning, be used to provide the power lead VDD of driving power, be used for selecting signal and luminous organic electroluminescent LED D1 connection according to the scanning of correspondence; It is characterized in that described image element circuit comprises:

Switching transistor T1, have grid that is connected with power lead VDD with the sweep trace SCAN of conllinear and the source electrode that is connected with data line DATA, be used to receive the signal that the sweep trace SCAN of conllinear and power lead VDD and data line DATA send and come the electric current of oxide-semiconductor control transistors T2 to flow;

Transistor T 2 has the drain electrode that is connected with power lead VDD with the sweep trace SCAN of conllinear, with switching transistor T1 drain electrode grid that is connected and the source electrode that is connected with organic electroluminescent LED D1, is used to provide organic electroluminescent LED D1 luminous electric current;

Capacitor C1 is connected between the earth terminal of the grid of transistor T 2 and organic electroluminescent LED D1, is used for keeping in the given time the voltage that transistor T 2 is applied.

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