TW201627970A - Driving method of current controlling OLED display panel and a display panel applying the same - Google Patents

Abstract

This invention discloses a driving method of current controlling OLED display panel and a display panel applying the same. The driving method comprises: a plurality of line scanning signals and a data signal which provide driving controlling current, light-emitting time of a line of the OLED devices were controlled by the corresponding line scanning signal. The plurality of line scanning signals is triggered successively. Each of the light-emitting signals provides a starting signal for controlling the corresponding OLED devices emitting light, and provides an ending signal for extinguishing the corresponding OLED devices. By means of adjusting the interval between the starting signal and the ending signal, to enable the light-emitting time of OLED devices becomes controllable.

Description

Current control OLED display panel driving method and display panel

The present invention relates to the field of AMOLED (Active Matrix Organic Light Emitting Diode), and more particularly to a current control driving method and a display panel for a display panel formed by an AMOLED device.

AMOLED has the characteristics of fast response, high contrast, wide viewing angle, etc., which makes AMOLED have a great advantage over TFT LCD (Thin Film Transistor Liquid Crystal Display). In addition, AMOLED has self-illuminating features and does not require backlight. The board is therefore thinner and more power efficient than the TFT LCD. There is also a more important feature. The AMOLED without the backlight can save 30%-40% of the backlight module.

Existing AMOLEDs are typically driven in a voltage controlled drive or current controlled drive. Among them, although the voltage control type circuit has a characteristic of fast response speed, it is difficult to satisfy the display requirement because the gray scale of the display cannot be accurately adjusted. In the case of low-brightness (low-gradation) driving, the current-driven driving method causes a response time delay due to a short charging time due to a small driving current.

The current-controlled AMOLED driving method disclosed in Chinese Patent Publication No. CN1316443C, in which a capacitor is pre-charged by adding a driving power source to overcome the defect that the charging time is too long, but the overall manufacturing cost is increased due to the increase of the device and the wiring. And the wiring is more difficult.

In view of the above problems existing in the conventional AMOLED driving method, there is now provided a driving method and a display panel of an OLED display panel which are intended to overcome the drawback of a low-brightness (low-gradation) driving time when the charging time is too long to cause a response delay. The specific technical solutions are as follows:

A driving method of a current-controlled OLED display panel, the display panel comprising a plurality of OLED devices, a plurality of row scanning signals, and a data signal for providing a driving control current, each of the row scanning signals controlling a row of the OLED device lighting time a plurality of the row scanning signals are sequentially triggered in sequence, the method includes: each of the row scanning signals provides a start signal to control corresponding OLED device illumination; and an end signal is provided to control corresponding OLED device to stop emitting light And controlling the illumination time of the corresponding OLED device by adjusting a time interval between the start signal and the end signal.

Preferably, a falling edge of the end signal of each of the line scan signals triggers a start signal of another of the line scan signals.

Preferably, a falling edge of the end signal triggers two of the line scan signals between the line scan signal of the start signal of another line scan signal and the line scan signal that is triggered.

Preferably, a falling edge of the start signal of each of the line scan signals triggers an end signal of another of the line scan signals.

Preferably, a falling edge of the start signal triggers a line scan signal between the line scan signal of the end signal of another line scan signal and the line scan signal that is triggered.

Preferably, the method further includes: setting a first time interval T _{1 in} a frame period of each of the line scan signals; setting a brightness threshold; calculating that the OLED device is turned off in the first time interval T1 a first driving current I ₁ required to reach the brightness threshold; and a second driving current I ₂ greater than the first driving current I ₁ and a second time interval T ₂ to cause the OLED device to The brightness threshold is reached by the off state during the second time interval T ₂ ; wherein T ₁ *I ₁ = T ₂ *I ₂ .

Preferably, the method further includes: setting the second driving current I ₂ to three times the first driving current I ₁ while the second time in each of the first time intervals T ₁ The interval T _{2 is} adjusted to 1/3 of the first time interval T ₁ .

Preferably, the method further includes: setting a first time interval T _{1 in} a frame period of each scan; setting a brightness threshold of the OLED device; and calculating to turn off the OLED device in the first time interval T ₁ the luminance state is reached a first threshold value required for driving current I _1; and providing a second drive current I _2, at the second time interval T is set to drive the OLED device ₂ reaches the closed state by the brightness threshold value; wherein The second driving current I _{2 is} greater than the first driving current I ₁ and the second time interval T _{2 is} less than the first time interval T ₁ .

Preferably, the method further includes: setting the second driving current I ₂ to twice the first driving current I ₁ while the second time in each of the first time intervals T ₁ The interval T _{2 is} adjusted to 1/3 of the first time interval T ₁ .

Preferably, the method further includes: setting the second driving current I ₂ to three times the first driving current I ₁ while the second time in each of the first time intervals T ₁ The interval T _{2 is} adjusted to 1/2 of the first time interval T ₁ .

Also included is a display panel in which the driving method of the display panel of any of the above-described current controls is used for driving.

The above technical solution has the beneficial effects of reducing the illumination time of the OLED device when the display requirement of the low-brightness (low gradation) range is reduced by adding a signal for controlling the illuminating time of the OLED device in the line scanning signal, thereby shortening the low brightness (low gradation) The charging time of the capacitor when the range is driven to overcome the defect that the charging time is too long when driving with low luminance (low gray scale), thereby causing a response delay, and does not increase the overall power consumption of the display panel.

The invention is further illustrated by the following figures and specific examples, but is not to be construed as limiting.

The present invention relates to a method for driving a current-controlled OLED display panel, wherein the display panel includes a plurality of OLED devices, a plurality of row scanning signals, and a data signal for providing a driving control current, and the plurality of OLED devices are arranged in a plurality of rows, each row scanning The signal controls the lighting time T of one row of OLED devices, and the plurality of row scanning signals are sequentially triggered in sequence, and the row scanning signals sequentially triggered in sequence can realize the progressive scanning of the display panel, and all the row scanning signals complete one trigger to form one frame period TF.

In the existing AMOLED driving technology, as shown in FIG. 1, the line scan signal provides only one pulse in one frame period TF to control the corresponding OLED device to start emitting light. Therefore, in the prior art, as shown in FIG. 5, the OLED device is shown in FIG. The light is emitted throughout the frame period TF. If the charging time required for low-brightness (low-gradation) display is compensated in the form of increasing current on the basis of the prior art, the energy consumption of the entire panel is increased.

For this phenomenon, as shown in FIG. 2, a start signal START can be provided in each row of scan signals to control the corresponding OLED device to emit light; and an end signal END is provided to control the corresponding OLED device to stop emitting light; by adjusting the start signal START and ending The time interval between the signals END controls the illumination time of the corresponding OLED device.

Based on the above technical solution, further, the falling edge of the end signal END of each of the plurality of row scan signals may trigger the start signal START of the other row of scan signals. As a preferred implementation, two line scan signals may be spaced between the line scan signal that triggers the start signal START of another line of scan signals and the line scan signal that is triggered by the falling edge of the end signal END.

Based on the above technical solution, further, the end signal END of the other scan signal may be triggered by the falling edge of the start signal START of each of the plurality of row scan signals. As a preferred embodiment, a line scan signal may be separated from the triggered line scan signal by the falling edge of the start signal START to trigger the end signal END of the other line of the scan signal.

Based on the above technical solution, further, a first time interval T _{1 in} a frame period of each line scan signal may be set; a brightness threshold F is set; and the OLED device is turned off in the first time interval T1. a first driving current I ₁ required to reach the brightness threshold F; and a second driving current I ₂ greater than the first driving current I ₁ and a second time interval T ₂ , which may be obtained by using the second driving current I ₂ The OLED device reaches a brightness threshold F from a closed state during a second time interval T ₂ ; wherein T ₁ *I ₁ = T ₂ *I ₂ .

The specific implementation method of the foregoing technical solution is to determine a relationship between brightness and current intensity when a display panel is normally displayed, and define a brightness threshold F, and a region below the brightness threshold on the relationship curve is defined as a low brightness range, higher than The area of the brightness threshold is defined as the high brightness range. What should be explained here is the relationship between the brightness and the current I intensity of the current control driving mode in the prior art, and a typical relationship curve in the prior art is shown in FIG. 3 . At the same time, the brightness can be divided into 0-255, and an intermediate value is set as the brightness threshold F in the range of 0-255. Of course, the specific value of the brightness threshold F can be determined according to actual needs. After the brightness threshold F is set, the first driving current I ₁ of the low brightness range display requirement in the prior art can be calculated by the relationship curve shown in FIG. 3 .

The first scan time T ₁ is equal to the frame period TF, and the second time interval T _{2 is} less than the frame period TF, and the display time required to maintain the display in the high brightness range, that is, the first time interval T ₁ is equal to the frame period TF; The data signal increases the display drive current required to be in the low luminance range, that is, the second drive current I ₂ , and maintains the display required drive current in the high luminance range. In the above solution, the second driving current I ₂ can be calculated by calculating the obtained first driving current I ₁ , the set first time interval T ₁ , the second time interval T ₂ , and the above-mentioned formula. 4 is a graph showing brightness versus current intensity determined in accordance with an embodiment of the above technical solution, wherein the second drive current I _{2 is} increased by N times, N when the display requirement is lower than the low brightness range of the brightness threshold F, N Is a natural number greater than 2. Figure 6 shows a second embodiment of the time set to one of the above technical solution of the embodiments of the interval T ₂ and the frame period TF is a schematic relationship, wherein, when the display request is less than the threshold value F luminance low-luminance range, the second time interval T ₂ Shortened to 1/N of the frame period TF.

The above technical solution achieves a faster charging time required for display in a low luminance range and improves a current intensity of a control current of a data signal required for display in a low luminance range, thereby realizing a charging speed of a capacitor in a driving circuit at a time of low luminance driving. The technical effect of improving the response speed of the OLED device.

As a preferred embodiment, the second driving current I ₂ can be set to be 3 times of the first driving current I ₁ , and the second time interval T ₂ in each of the first time intervals T ₁ can be adjusted to 1/3 of the first time interval T ₁ .

The above technical solution can also be implemented in the form described below by changing the setting, setting the first time interval T _{1 in} each scanning frame period; setting the brightness threshold F of the OLED device; calculating in the first time interval T ₁ The first driving current I ₁ required to bring the OLED device from the off state to the brightness threshold F; and the second driving current I ₂ to be driven by the second driving current I ₂ during the set second time interval T ₂ The off state reaches the brightness threshold F;

Wherein the second drive current I _{2 is} greater than the first drive current I ₁ and the second time interval T _{2 is} less than the first time interval T ₁ .

This embodiment does not limit the ratio relationship between the second time interval T ₂ and the first time interval T ₁ , and the second drive current I ₂ and the first drive current I ₁ .

As a preferred implementation, the second driving current I ₂ can be set to twice the first driving current I ₁ , and the second time interval T ₂ in each of the first time intervals T ₁ can be adjusted to 1/3 of the first time interval T ₁ .

As a preferred embodiment, the second driving current I ₂ can also be set to 3 times of the first driving current I ₁ while adjusting the second time interval T ₂ in each of the first time intervals T ₁ to The first time interval T ₁ is 1/2.

The technical solution of the present invention further includes a display panel, wherein the driving method of the current controlled OLED display panel is used for driving.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the embodiments and the scope of the present invention, and those skilled in the art should be able to Alternatives and obvious variations are intended to be included within the scope of the invention.

START‧‧‧ starting signal;
END‧‧‧ end signal;
F‧‧‧ brightness threshold;
I‧‧‧ current;
I ₁ ‧‧‧first drive current;
N‧‧‧ natural numbers greater than 2;
TF‧‧ frame period;
T‧‧‧ luminous time;
T ₂ ‧‧‧ second time interval

1 is a timing chart of a line scan signal of a conventional current control AMOLED driving method;

2 is a timing chart of a line scan signal of a driving method of a current controlled OLED display panel of the present invention;

3 is a graph showing brightness versus current intensity of a data signal of a conventional current controlled AMOLED driving method;

4 is a graph showing brightness and current intensity of a data signal of a driving method of a current-controlled OLED display panel of the present invention;

5 is a diagram showing relationship between a device illumination time and a frame period in a conventional current control AMOLED driving method;

6 is a diagram showing the relationship between the device illumination time and the frame period of the driving method of the current-controlled OLED display panel of the present invention.

START‧‧‧Start signal

END‧‧‧End signal

Claims (11)

A driving method of a current-controlled Organic Light-Emitting Diode (OLED) display panel, the display panel comprising a plurality of OLED devices, a plurality of row scanning signals, and a data signal for providing a driving control current, Each of the row scan signals controls a row of the OLED device to emit light, and the plurality of row scan signals are sequentially triggered in sequence, the method comprising: each of the row scan signals providing a start signal to control the corresponding OLED device Illuminating; providing an end signal control corresponding to the OLED device to stop emitting light; and controlling a corresponding lighting time of the OLED device by adjusting a time interval between the start signal and the end signal. The driving method of claim 1, wherein a falling edge of an end signal of each of the line scanning signals triggers a start signal of another of the line scanning signals. The driving method of claim 2, wherein the falling edge of the end signal triggers the line scan signal of the start signal of another line scan signal and the line scan signal that is triggered Two of the line scan signals are spaced apart. The driving method of claim 1, wherein a falling edge of a start signal of each of the line scan signals triggers an end signal of another of the line scan signals. The driving method of claim 4, wherein a falling edge of the start signal triggers an interval between a line scan signal of an end signal of another line scan signal and the line scan signal that is triggered. One of the line scan signals. The driving method of claim 1, further comprising: setting a first time interval T _{1 in} a frame period of each of the line scan signals; setting a brightness threshold; calculating at the first time interval T1 a first driving current I ₁ required to bring the OLED device from the off state to the brightness threshold; and a second driving current I ₂ greater than the first driving current I ₁ and a second time interval T ₂ , causing the OLED device to reach the brightness threshold from a closed state during the second time interval T ₂ ; wherein T ₁ *I ₁ = T ₂ *I ₂ . The driving method of claim 6, further comprising: setting the second driving current I ₂ to three times the first driving current I ₁ while at each of the first time intervals ₁ T in the second time interval T ₂ is adjusted to the first time interval of 1/3 T _1. The driving method of claim 1, further comprising: setting a first time interval T _{1 in} a frame period of each scan; setting a brightness threshold of the OLED device; calculating at the first time interval T ₁ within the OLED device reaches the closed state by the brightness threshold current needed to drive the I ₁ first; and providing a second drive current I _2, at a second set of time T within the OLED _driving means by the interval The off state reaches the brightness threshold; wherein the second drive current I _{2 is} greater than the first drive current I ₁ and the second time interval T _{2 is} less than the first time interval T ₁ . The driving method of claim 8, further comprising: setting the second driving current I ₂ to twice the first driving current I ₁ while at each of the first time intervals ₁ T in the second time interval T ₂ is adjusted to the first time interval of 1/3 T _1. The driving method of claim 8, further comprising: setting the second driving current I ₂ to three times the first driving current I ₁ while at each of the first time intervals ₁ T in the second time interval T ₂ is adjusted to the first time interval of 1/2 T _1. A display panel is improved in that it is driven by a driving method as described in any one of claims 1-10.