CN100435349C - An active organic light emitting diode panel and its control method - Google Patents

Abstract

The invention discloses an active organic light emitting diode panel and a control method thereof. The active organic light emitting diode panel includes a pixel array, a temperature sensor and a feedback control circuit, wherein the temperature sensor is used to detect the active organic light emitting diode panel operating temperature, and the feedback control circuit adjusts the operating current of the active organic light emitting diode panel according to the result sensed by the temperature sensor; The data voltage or the common voltage of the pixel unit, so that the magnitude of the working current of the pixel array is inversely proportional to the magnitude of the working temperature detected by the temperature sensor. The size of the working current of the present invention is inversely proportional to the working temperature detected by the temperature sensor, mainly to avoid the high temperature and high current of the active organic light emitting diode panel and prolong the service life of the panel.

Description

An active organic light emitting diode panel and its control method

technical field

The invention relates to an active organic light emitting diode panel, in particular to a method for adjusting the operating current to control the temperature of the active organic light emitting diode panel.

Background technique

Compared with liquid crystal display panels, Organic Light Emitting Diode (OLED) panels have the advantages of fast response time, light weight, no viewing angle limitation, and high contrast, so they have become one of the main research focuses of display panels in recent years. According to the driving method of OLEDs, they can be roughly divided into Passive Matrix Organic Light Emitting Diode (PMOLED) panels and Active Matrix Organic Light Emitting Diode (AMOLED) panels. Among them, the AMOLED panel is suitable for display panels with high resolution and large size.

Since the pixel brightness of the AMOLED panel is proportional to the conduction current of the OLED, the magnitude of the conduction current is determined by the transistor. When the operating temperature of the AMOLED panel continues to increase, the initial voltage of the transistor will gradually decrease, so that the current generated by the drain terminal of the transistor will increase, and the anode terminal of the light-emitting diode is coupled to the drain terminal of the transistor, so the current flowing through the organic light-emitting diode The current will also increase. However, the AMOLED panel contains a large amount of organic materials. Under the condition of high temperature and high current, it is easy to accelerate the deterioration of the AMOLED panel and shorten the service life of the panel.

Figure 1 shows the trend of the overall driving current of the existing panel at different temperatures. Please refer to FIG. 1 , in the prior art, as the temperature of the AMOLED panel increases, its driving current will also increase accordingly, that is, the temperature of the AMOLED panel is directly proportional to the driving current. This means that as the temperature of the AMOLED panel increases, the current flowing through the organic light emitting diode will also increase, so that the deterioration of the AMOLED panel will be accelerated and the service life will be shortened.

Contents of the invention

Therefore, the purpose of the present invention is to provide a flat panel display and its AMOLED panel, which can adjust the size of the operating current according to the temperature change during operation.

From another point of view, the object of the present invention is to provide a method for controlling an AMOLED panel, which can control the driving current of the AMOLED panel to be inversely proportional to its operating temperature.

The AMOLED panel provided by the present invention includes a pixel array, a temperature sensor and a feedback control circuit. Wherein, the pixel array has a plurality of pixel units arranged in an array, and the temperature sensor is used to detect the working temperature of at least part of the pixel units. In this way, the feedback control circuit can adjust the magnitude of the working current of the pixel array according to the result sensed by the temperature sensor. In the present invention, the feedback control circuit can control the magnitude of the working current of the pixel array to be inversely proportional to the magnitude of the working temperature detected by the temperature sensor; The data voltage or the common voltage of the pixel unit, so that the magnitude of the working current of the pixel array is inversely proportional to the magnitude of the working temperature detected by the temperature sensor.

From another point of view, the present invention provides a flat panel display including an AMOLED panel, a temperature sensor and a feedback control circuit. Wherein, the AMOLED panel has a plurality of pixel units, and the temperature sensor is used to detect the working temperature of the AMOLED panel. In addition, the feedback control circuit can adjust the working current of the AMOLED panel according to the result sensed by the temperature sensor. In the present invention, the feedback control circuit controls the operating current of the AMOLED panel to be inversely proportional to the operating temperature detected by the temperature sensor; wherein the feedback control circuit adjusts the AMOLED panel according to the operating temperature detected by the temperature sensor. The data voltage or the common voltage of the pixel unit, so that the magnitude of the working current of the pixel array is inversely proportional to the magnitude of the working temperature detected by the temperature sensor.

From another point of view, the present invention provides a method for controlling an AMOLED panel. First, a temperature sensor is used to detect the operating temperature of at least a part of the AMOLED panel, and the detection result is sent to the feedback control circuit, and then the feedback control circuit adjusts the operating current of the AMOLED panel according to the detection result, so that the operating current of the AMOLED panel is equal to the operating temperature of the AMOLED panel. The magnitude of the working temperature is inversely proportional; the feedback control circuit adjusts the data voltage or the common voltage of the pixel unit according to the detection result, so that the magnitude of the working current of the active organic light emitting diode panel is proportional to the magnitude of the working temperature of the detected area Inversely.

Since the present invention uses a temperature sensor to detect the working temperature of the AMOLED panel, and then adjusts the working current of the AMOLED panel according to the working temperature detected by the temperature sensor through the feedback control circuit, which is inversely proportional to the working temperature. Therefore, when the operating temperature of the AMOLED panel increases, the conduction current of the OLED will decrease, thereby prolonging the service life of the panel.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

Description of drawings

Fig. 1 is the relationship between the driving current and the temperature of the active organic light emitting diode panel in the prior art;

2 is a circuit block diagram of an active organic light emitting diode panel according to a preferred embodiment of the present invention;

3 is a circuit diagram of a pixel unit according to a preferred embodiment of the present invention;

Fig. 4 is the relationship between the driving current and temperature of the active organic light emitting diode panel of the present invention;

FIG. 5 is a circuit block diagram of an active OLED panel according to another preferred embodiment of the present invention.

Among them, reference signs:

200 flat panel displays

210 AMOLED panel

212 temperature sensor

214 Feedback control circuit

220 scan line drive circuit

222 data line drive circuit

224 pixel array

228 pixel units

2281 pixel units

230 scan lines

234 data cable

310, 312 transistors

320 OLEDs

Detailed ways

FIG. 2 is a circuit block diagram of an active organic light emitting display according to a preferred embodiment of the present invention. Referring to FIG. 2 , the present invention provides a flat panel display 200 including an AMOLED panel 210 , a temperature sensor 212 and a feedback control circuit 214 . Wherein, the temperature sensor 212 is disposed on the AMOLED panel 210 to detect the working temperature of the AMOLED panel 210 during operation, and send the detected result to the feedback control circuit 214 .

The AMOLED panel 210 includes a scanning line driving circuit 220 , a data line driving circuit 222 , and a pixel array 224 . Wherein, the pixel array 224 has a plurality of pixel units 228 arranged in an array. The scanning line driving circuit 220 is coupled to the pixel array 224 through a plurality of scanning lines 230 , and the data line driving circuit 222 is coupled to the pixel array 224 through a plurality of data lines 234 .

FIG. 3 is a circuit diagram of a pixel unit 2281 according to a preferred embodiment of the present invention, which can be applied to the pixel unit 228 in FIG. 2 . Referring to FIG. 3 , the pixel unit 2281 includes transistors 310 and 312 , and an organic light emitting diode 320 . In this embodiment, the transistors 310 and 312 may be realized by using NMOS (N-Type Metal Oxide Semiconductor, N-Type Metal Oxide Semiconductor) transistors. Wherein, the gate terminal of the transistor 310 is coupled to a scan line 230 , the source terminal is coupled to a data line 234 , and the drain terminal is coupled to the gate terminal of the driving transistor 312 . In addition, the source terminal of the transistor 312 is coupled to a voltage source V _DD , the drain terminal is coupled to the anode terminal of the OLED 320 , and is coupled to a common voltage Vss through the cathode terminal of the OLED 320 . In an embodiment of the present invention, the common voltage Vss may be a ground potential.

Please refer to FIG. 2 and FIG. 3 together. In FIG. 2 , the scan line driving circuit 220 is used for generating scan signals, and the data line driving circuit 222 is used for generating data voltages. When the pixel unit 2281 is to be driven, the scan line driving circuit 220 first enables the scan signal on the scan line 230 coupled to the pixel unit 2281 , so that the transistor 310 is turned on. At this time, the data line driving circuit 222 outputs a data voltage signal, which is sent to the pixel unit 2281 through the data line 234 , and is sent to the gate of the driving transistor 312 through the transistor 310 . Accordingly, the transistor 312 is activated and generates a driving current _ID to drive the OLED 320 .

It can be known from FIG. 3 that the magnitude of the driving current _ID is related to the data voltage, the working voltage and the common voltage. Therefore, the present invention utilizes this characteristic to adjust the magnitude of the driving current.

Please refer to FIG. 2 and FIG. 3 together. In FIG. 2 , when the AMOLED panel 210 works for a period of time, its operating temperature will continue to rise. If the temperature sensor 212 detects that the working temperature of some pixel units of the AMOLED panel 210 rises, the feedback control circuit 214 will lower the data voltage through the data line driving circuit 222 . At this time, the gate terminal voltage of the transistor 312 also decreases, so that the operating voltage of the transistor 312 decreases. Since the operating voltage of the transistor 312 decreases, the driving current _ID generated by the transistor 312 decreases, so that the driving current _ID flowing through the LED decreases.

FIG. 4 shows the trend of the overall driving current of the panel of the present invention at different temperatures. Please refer to FIG. 4 , the feedback control circuit 214 in FIG. 2 controls the operating current of the AMOLED panel according to the detection result of the temperature sensor 212 , which is inversely proportional to the operating temperature of the detected area. Therefore, when the working temperature of the AMOLED panel rises, the driving current _ID decreases accordingly, which can make the AMOLED panel not easy to accelerate deterioration, and meanwhile prolong the service life of the panel.

FIG. 5 is a circuit block diagram of an active organic light emitting display according to another preferred embodiment of the present invention. Referring to FIG. 5 , the present invention provides a flat panel display 200 including an AMOLED panel 210 , a temperature sensor 212 and a feedback control circuit 214 . Wherein, the temperature sensor 212 is disposed on the AMOLED panel 210 to detect the working temperature of the AMOLED panel 210 during operation, and send the detected result to the feedback control circuit 214 .

Please refer to FIG. 2 and FIG. 3 together. In FIG. 2 , when the AMOLED panel 210 works for a period of time, its operating temperature will continue to rise. If the temperature sensor 212 detects that the operating temperature of some pixel units of the AMOLED panel 210 rises, the feedback control circuit 212 will lower the operating voltage V _DD of the transistor 312 . In FIG. 3 , since the operating voltage V _DD of the transistor 312 decreases, the voltage gap between the operating voltage V _DD and the common voltage Vss decreases, so that the driving current _ID generated by the transistor 312 also decreases. Therefore, the driving current _ID of the organic light emitting diode is also reduced accordingly, so that the deterioration of the AMOLED panel will not be accelerated, and the service life of the AMOLED panel can also be extended.

To sum up, the present invention proposes to use the temperature sensor to detect the working temperature of the AMOLED panel, and according to the result sensed by the temperature sensor, adjust the working current of the AMOLED panel through the feedback control circuit in the same manner as the working temperature detected by the temperature sensor. inverse ratio. Therefore, when the AMOLED panel is operated at high temperature, its operating current will decrease accordingly, so that the AMOLED panel of the present invention is not easy to deteriorate, and the service life of the panel is prolonged.

Of course, the present invention can also have other various embodiments, and those skilled in the art can make various corresponding changes and deformations according to the present invention without departing from the spirit and essence of the present invention, but these corresponding Changes and deformations should belong to the scope of protection of the appended claims of the present invention.

Claims (9)

1, a kind of active organic LED panel is characterized in that, comprising:

One pel array has a plurality of pixel cells with arrayed;

One temperature sensor is used to detect the working temperature to small part of described pixel cell; And

One feedback control circuit according to this temperature sensor institute sensed result, and is adjusted the operating current size of this pel array,

Wherein this feedback control circuit is the data voltage that the size adjustment of the working temperature that detects according to this temperature sensor is input to described pixel cell, so that the size of the working temperature that the size of the operating current of this pel array and this temperature sensor are detected is inverse ratio.

2, active organic LED panel according to claim 1 is characterized in that, described each pixel cell comprises:

One first nmos pass transistor, its source terminal receives described data voltage, and its gate terminal then receives the one scan signal;

One second nmos pass transistor, its source terminal couples an operating voltage, and its gate terminal then couples the drain electrode end of this first nmos pass transistor; And

One Organic Light Emitting Diode assembly, its anode tap couples the drain electrode end of this second nmos pass transistor, and its cathode terminal then couples a common voltage.

3, active organic LED panel according to claim 2 is characterized in that, the current potential of this common voltage is an earthing potential.

4, a kind of active organic LED panel is characterized in that, comprising:

One pel array has a plurality of pixel cells with arrayed;

One temperature sensor is used to detect the working temperature to small part of described pixel cell; And

One feedback control circuit according to this temperature sensor institute sensed result, and is adjusted the operating current size of this pel array,

Wherein this feedback control circuit is the common voltage that the size of the working temperature that detects according to this temperature sensor is adjusted described pixel cell, is inverse ratio with the size of the operating current of controlling this pel array and the size of the working temperature that this temperature sensor is detected.

5, a kind of flat-panel monitor is characterized in that, comprising:

One active organic LED panel has a plurality of pixel cells, is to arrange with array way;

One temperature sensor is used to detect the working temperature of this active organic LED panel; And

One feedback control circuit according to this temperature sensor institute sensed result, and is adjusted the operating current size of this active organic LED panel,

Wherein this feedback control circuit is the data voltage that the size adjustment of the working temperature that detects according to this temperature sensor is input to described pixel cell, so that the size of the working temperature that the size of the operating current of this active organic LED panel and this temperature sensor are detected is inverse ratio.

6, flat-panel monitor according to claim 5 is characterized in that, described each pixel cell comprises:

One first nmos pass transistor, its source terminal receives described data voltage, and its gate terminal then receives the one scan signal;

One second nmos pass transistor, its source terminal couples an operating voltage, and its gate terminal then couples the drain electrode end of this first nmos pass transistor; And

One Organic Light Emitting Diode assembly, its anode tap couples the drain electrode end of this second nmos pass transistor, and its cathode terminal then couples a common voltage.

7, flat-panel monitor according to claim 6 is characterized in that, the current potential of this common voltage is an earthing potential.

8, a kind of flat-panel monitor is characterized in that, comprising:

One active organic LED panel has a plurality of pixel cells, is to arrange with array way;

One temperature sensor is used to detect the working temperature of this active organic LED panel; And

One feedback control circuit according to this temperature sensor institute sensed result, and is adjusted the operating current size of this active organic LED panel,

Wherein this feedback control circuit is the common voltage that the size of the working temperature that detects according to this temperature sensor is adjusted described pixel cell, is inverse ratio with the size of the operating current of controlling this pel array and the size of the working temperature that this temperature sensor is detected.

9, a kind of control method of active organic LED panel is characterized in that, comprises the following steps:

Detect the working temperature of the subregion at least of this active organic LED panel, and produce a testing result; And

Adjust the data voltage or the common voltage of pixel cell according to this testing result, so that the size of the working temperature of the size of the operating current of this active organic LED panel and institute's surveyed area is inverse ratio.

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