AMOLED display device and method for precisely compensating for the aging of this device.

Abstract

AMOLED display device with: a display screen that features AMOLED-based pixels; a data processor that processes image data from a video source and compensation data from a compensation unit and outputs compensated image data, wherein the image data has a first color depth, and the compensation data and the compensated image data have a second color depth that is greater than the first color depth; a single frame rate control module that sets the compensated image data to the first color depth; a timing controller that generates a timing control signal corresponding to an output signal from the frame rate control module; a driver that drives the display screen according to the timing control signal; a display measurement module that measures the homogeneity of the display screen; and a compensation unit that generates compensation data for the second color depth according to the measurement result of the display measurement module and outputs it to the data processor.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present invention relates to AMOLED display technologies and in particular to an AMOLED display device and a method for precisely compensating for the aging of this device. 2. Relevant state of the art

[0002] AMOLED (Active Matrix Organic Light-Emitting Diode) screens offer several advantages compared to conventional liquid crystal screens, such as high response speed, high contrast and a wide viewing angle.

[0003] The publications US 2010 0060660 A1, US 2012 0032991 A1 and WO 2006 108 277 A1 concern relevant state of the art.

[0004] An AMOLED is a type of OLED (Organic Light-Emitting Diode). The light emission of an OLED is achieved through electroluminescence, which is caused by the injection and recombination of organic semiconductor and light-emitting material substrates under an electric field. The principle of light emission in an OLED involves using an ITO (indium tin oxide) transparent electrode and a metal electrode as the anode and cathode of the device. When driven by an electric field, electrons and holes are injected from the cathode and anode into electron and hole transport layers, respectively.The electrons and holes move through the electron and hole transport layers to a light-emitting layer and collide there to form excitons. These excitons excite light-emitting molecules, which then emit visible light due to radiation relaxation. The emitted light can be observed on one side of the ITO. The metal electrode layer also serves as a reflective layer.

[0005] Compared to a TFT-LCD (Thin-Film Transistor Liquid Crystal Display), an OLED has several advantages, such as thinner and lighter design, active light emission (no need for backlighting), freedom from viewing angle problems, high sharpness, high brightness, fast response, low energy consumption, wide operating temperature range, excellent resistance to vibration, low cost, and the ability to display flexibly, some of which are not possible with a TFT liquid crystal screen.

[0006] In contrast, an AMOLED display uses an electric current flowing through organic material to emit light. Different organic materials emit light of different colors. When using an AMOLED display, the organic material within the device can undergo an aging process, which reduces its light emission efficiency and thus shortens the device's lifespan. Different organic materials can age at different rates, causing varying degrees of color fading. Furthermore, the white area of ​​a display can change with use. Additionally, each pixel can age at a different rate than the other pixels, resulting in a non-uniform display.Therefore, certain compensation measures must be taken in an AMOLED display device to maintain the properties of the display device.

[0007] Fig. Figure 1 shows a schematic view illustrating the structure of a conventional AMOLED display device equipped with aging compensation. The AMOLED display device comprises: a display screen 11 with AMOLED-based pixels; a data processor 12 that processes image data from a video source and compensation data from a compensation unit 16 and outputs compensated image data; a timing controller (TCON) 13 that generates a timing control signal according to the output signal from the data processor 12; a driver 14 that drives the display screen 11 according to the timing control signal; a display measurement module 15 that measures the homogeneity of the display screen 11; and a compensation unit 16 that generates compensation data according to the measurement result of the display measurement module 15 and outputs it to the data processor 12.Regarding the details of the implementation of the functions of the compensation unit 16 and the display-measuring module 15, reference is made to the disclosures of Chinese patent application no. CN 101194300 A and Chinese patent no. CN 1886774 B.

[0008] Image data with an 8-bit color depth, originating from a video source, is transmitted to the data processor 12, and the 8-bit color depth image data processed by the data processor 12 is transmitted to the timing controller 13. The primary function of the timing controller 13 is to supply the necessary timing control signals to a source driver and a gate driver. The timing sequence of the timing controller 13 is determined by the data structure and display mode of the image data. The timing control signal, which contains the 8-bit color depth information, is transmitted to the driver 14. The driver 14 generally consists of a source driver and a gate driver. The driver 14 drives the display screen 11 according to the 8-bit color depth and converts this into an electrical current to drive the OLEDs of the display screen 11 so that the display screen emits visible light.Since the aging characteristics of the AMOLED display device change over time, the display result required by the image data differs from the actual display result on the display screen 11, leading to an inhomogeneous display. Consequently, aging compensation can be performed on the OLEDs. The display measurement module 15 is used to measure the display homogeneity of the display screen 11, and then the compensation unit 16 generates compensation data with an 8-bit color depth. The compensation data is transmitted to the data processor 12 to be processed and mixed with the image data in such a way as to compensate for the image data. The compensated 8-bit color depth image data is then transmitted to the timing controller 13 and subsequently fed to the driver 14 to drive the display screen.

[0009] However, since conventional aging compensation requires the driver's integrated circuit (IC) to perform a level adjustment of at least one after conversion to electrical current, the current difference between two adjacent levels is significant, making precise compensation impossible. A special condition arises from Fig. Figure 2 shows the Ids-Vgs characteristic curve of the IC circuit driving the OLEDs for Vds of -10 V and -0.1 V. Fig. 2. It can be seen that, although the values ​​of Vds may be very close to each other, the values ​​of Ids still differ considerably.

[0010] On the other hand, the result of the display using liquid crystals is determined by the effective voltage applied to the liquid crystal. The grayscale level (color) of the liquid crystal can be generated in two ways: by PWM (Pulse Width Modulation) and FRC (Frame Rate Control). PWM divides a sampling period into several time slices. For example, in a 256-level grayscale gradient, this division into 256 time slices is performed. The number of time slices that can be implemented with a single driver voltage is determined by the desired grayscale level.

[0011] Fig. Figure 3 shows a schematic view to illustrate the principle of conventional FRC technology. FRC technology is a technique used to control the frame rate to visibly increase the number of colors by exploiting the phenomenon of persistence of vision in the human eye. FRC employs a time-averaging method to trick the human eye into perceiving different brightness levels. FRC is similar to PWM, except that "time slice" is replaced by "frame." Fig. As shown in Figure 3, four time slices correspond to the first, second, third, and fourth images, respectively. For a liquid crystal, the state in which it is subjected to a driving voltage means that it displays black. Due to the persistence of vision, different optical shades of gray can be perceived based on an arrangement of four successive time slices, which correspond to the individual images present with or without the driving voltage. The way colors are displayed with a liquid crystal is similar to how a shade of gray is achieved and is actually a modulation of the shades of gray for the three primary colors red, green, and blue. OVERVIEW OF THE INVENTION

[0012] Therefore, the object of the present invention is to create an AMOLED display device in which the precision of the compensation of the aging compensation of OLEDs is improved.

[0013] Another object of the present invention is to provide a method for precisely compensating for the aging of an AMOLED display device.

[0014] To solve the problems, the present invention provides an AMOLED display device which has: a display screen that features AMOLED-based pixels; a data processor that processes image data from a video source and compensation data from a compensation unit and outputs compensated image data, wherein the image data has a first color depth, and the compensation data and the compensated image data have a second color depth that is greater than the first color depth; a single frame rate control module that sets the compensated image data to the first color depth; a timing controller that generates a timing control signal corresponding to an output signal from the frame rate control module; a driver that drives the display screen according to the timing control signal; a display measurement module that measures the homogeneity of the display screen; and a compensation unit that generates compensation data for the second color depth according to the measurement result of the display measurement module and outputs it to the data processor.

[0015] The first color depth is 8 bits.

[0016] The second color depth is 10 bits.

[0017] The compensation unit has a look-up table.

[0018] The display screen supports the first color depth.

[0019] The present invention further provides a method for precisely compensating an AMOLED display device, comprising: • (1) by means of the data processor, processing image data from a video source and compensation data from a compensation unit and outputting compensated image data, wherein the image data has a first color depth, and the compensation data and the compensated image data have a second color depth which is greater than the first color depth; • (2) using the frame rate control module, setting the compensated image data to the first color depth; • (3) by means of the timing controller, generating a timing control signal corresponding to an output signal from the frame rate control module; • (4) by means of the driver, driving a display screen having AMOLED-based pixels according to the timing control signal; • (5) using the display measurement module, measuring the homogeneity of the display screen; and • (6) by means of the compensation unit, generating compensation data of the second color depth according to the measurement result of the display measurement module and outputting the compensation data to the data processor.

[0020] The first color depth is 8 bits.

[0021] The second color depth is 10 bits.

[0022] The compensation unit has a look-up table.

[0023] The display screen supports the first color depth.

[0024] The present invention further provides an AMOLED display device which comprises: a display screen that features AMOLED-based pixels; a data processor that processes image data from a video source and compensation data from a compensation unit and outputs compensated image data, wherein the image data has a first color depth, and the compensation data and the compensated image data have a second color depth that is greater than the first color depth; a single frame rate control module that sets the compensated image data to the first color depth; a timing controller that generates a timing control signal corresponding to an output signal from the frame rate control module; a driver that drives the display screen according to the timing control signal; a display measurement module that measures the homogeneity of the display screen; and a compensation unit that generates compensation data for the second color depth according to the measurement result of the display measurement module and outputs it to the data processor; and where the first color depth is 8 bits; where the second color depth is 10 bits; wherein the compensation unit has a look-up table; and where the display screen supports the first color depth.

[0025] The present invention provides an AMOLED display device in which the precision of the aging compensation of OLEDs is improved. The present invention provides a method for precisely compensating for the aging of an AMOLED display device, in which the precision of the compensation of the AMOLED display device is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The technical solution and the advantageous features of the present invention will become apparent from the following detailed description of one embodiment of the present invention with reference to the accompanying drawings. The drawings show the following: Fig. Figure 1 shows a schematic view to illustrate the structure of a conventional AMOLED display device equipped with aging compensation; Fig. Figure 2 shows the Ids-Vgs characteristic curve of an integrated circuit driving OLEDs, for Vds equal to -10 V and -0.1 V; Fig. Figure 3 shows a schematic view to illustrate the principle of conventional FRC technology. Fig. Figure 4 shows a schematic view to illustrate the structure of an AMOLED display device according to a preferred embodiment of the present invention; and Fig. Figure 5 shows a flowchart to illustrate a method designed according to the present invention for precisely compensating for the aging of an AMOLED display device. DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS

[0027] According to Fig. Figure 4, which shows a schematic view illustrating the structure of an AMOLED (Active Matrix Organic Light-Emitting Diode) display device according to a preferred embodiment of the present invention, the AMOLED display device essentially comprises: a display screen 41 having AMOLED-based pixels; a data processor 42 that processes image data from a video source and compensation data from a compensation unit 46 and outputs compensated image data, wherein the image data has a first color depth, and the compensation data and the compensated image data have a second color depth greater than the first color depth; a frame rate control module 47 that sets the compensated image data to the first color depth; a timing controller 43 that generates a timing control signal corresponding to an output signal from the frame rate control module 47;a driver 44 that drives the display screen 41 according to the timing control signal; a display measurement module 45 that measures the homogeneity of the display of the display screen 41; and a compensation unit 46 that generates compensation data of the second color depth according to the measurement result of the display measurement module 45 and outputs it to the data processor 42.

[0028] Image data with an 8-bit color depth from a video source is transferred to the data processor 42. The data processor 42 processes the 8-bit color depth image data from the video source and the 10-bit color depth compensation data from the compensation unit 46, and outputs compensated image data with a 10-bit color depth. The frame rate control module 47 adjusts the compensated 10-bit color depth image data to an 8-bit color depth for transmission to the timing controller 43. The timing control signal, which contains the 8-bit color depth information, is transmitted to the driver 44. The driver 44 drives an OLED of the display screen 41 such that it outputs visible light according to the 8-bit color depth timing control signal. To form a compensation circuit, the display measurement module 45 measures the display homogeneity of the display screen 41, and then the compensation unit 46 generates compensation data of a 10-bit color depth.The compensation data is transmitted to the data processor 42 to be processed and mixed in combination with the image data in such a way that the display result required by the image data is consistent with the actual display result realized on the display screen 41, thereby making the display homogeneous.

[0029] Similar to how grayscale (color) is achieved in a liquid crystal, the display output of an AMOLED display device can be adjusted using a frequency-correcting (FRC) method. According to the present invention, the aging compensation data is modified to increase its color depth, specifically increasing the color depth from 8 bits to 10 bits, since the number of color depth bits that can be received by the display screen is lower. Thus, the use of the FRC method allows the display output to show larger color depth data, thereby improving the precision of the compensation.

[0030] In the present invention, the condition must be met that the second color depth is greater than the first color depth. Besides the concept of the first color depth being 8 bits and the second color depth being 10 bits, other suitable concepts are also available. The display screen 41 is preferably designed to support the first color depth exactly. A display screen 41 designed for a smaller color depth than the first color depth is unable to support the normal display of image data, and a display screen 41 designed for a larger color depth than the first color depth incurs higher costs. Furthermore, with a display screen 41 designed for a larger color depth than the second color depth or for the same color depth, the use of the frame rate control module 47 is not required.The compensation unit 46 can have a look-up table to assist in generating second color depth compensation data.

[0031] According to Fig. Figure 5, which shows a flowchart illustrating a method designed according to the present invention for precisely compensating for the aging of an AMOLED display device, comprises the method:

[0032] Step 51: using the data processor, processing image data from a video source and compensation data from a compensation unit and outputting compensated image data, wherein the image data has a first color depth, and the compensation data and the compensated image data have a second color depth that is greater than the first color depth;

[0033] Step 52: using the frame rate control module, adjust the compensated image data to the first color depth;

[0034] Step 53: using the timing controller, generate a timing control signal corresponding to an output signal from the frame rate control module;

[0035] Step 54: using the driver, driving a display screen that has AMOLED-based pixels, according to the timing control signal;

[0036] Step 55: using the display measurement module, measuring the homogeneity of the display screen; and

[0037] Step 56: using the compensation unit, generating compensation data of the second color depth according to the measurement result of the display measurement module and outputting the compensation data to the data processor.

[0038] The first color depth is 8 bits, and the second color depth is 10 bits. The display screen supports the first color depth. The compensation unit can have a lookup table to support the generation of compensation data for the second color depth.

[0039] In summary, the present invention provides an AMOLED display device in which the precision of the aging compensation of OLEDs is improved. The present invention provides a method for precisely compensating for the aging of an AMOLED display device, thereby improving the precision of the compensation of the AMOLED display device.

[0040] Based on the foregoing description, a person skilled in the art can easily see various changes and modifications that may be made to the technical solution and the technical ideas of the present invention, and all such changes and modifications fall within the scope of legal protection of the present invention.

Claims

[1] AMOLED display device with: a display screen that features AMOLED-based pixels; a data processor that processes image data from a video source and compensation data from a compensation unit and outputs compensated image data, wherein the image data has a first color depth, and the compensation data and the compensated image data have a second color depth that is greater than the first color depth; a single frame rate control module that sets the compensated image data to the first color depth; a timing controller that generates a timing control signal corresponding to an output signal from the frame rate control module; a driver that drives the display screen according to the timing control signal; a display measurement module that measures the homogeneity of the display screen; and a compensation unit that generates compensation data for the second color depth according to the measurement result of the display measurement module and outputs it to the data processor. [2] AMOLED display device according to claim 1, wherein the first color depth is 8 bits. [3] AMOLED display device according to claim 1, wherein the second color depth is 10 bits. [4] AMOLED display device according to claim 1, wherein the compensation unit comprises a look-up table. [5] AMOLED display device according to claim 1, wherein the display screen supports the first color depth. [6] Method for precisely compensating for the aging of an AMOLED display device, comprising: (1) by means of the data processor, processing image data from a video source and compensation data from a compensation unit and outputting compensated image data, wherein the image data has a first color depth, and the compensation data and the compensated image data have a second color depth which is greater than the first color depth; (2) using the frame rate control module, adjusting the compensated image data to the first color depth; (3) by means of the timing controller, generating a timing control signal corresponding to an output signal from the frame rate control module; (4) by means of the driver, driving a display screen having AMOLED-based pixels, according to the timing control signal; (5) using the display measurement module, measuring the homogeneity of the display screen; and (6) by means of the compensation unit, generating compensation data of the second color depth according to the measurement result of the display measurement module and outputting the compensation data to the data processor. [7] Method for precisely compensating an AMOLED display device according to claim 6, wherein the first color depth is 8 bits. [8] Method for precisely compensating an AMOLED display device according to claim 6, wherein the second color depth is 10 bits. [9] Method for precisely compensating an AMOLED display device according to claim 6, wherein the compensation unit comprises a look-up table. [10] Method for precisely compensating an AMOLED display device according to claim 6, wherein the display screen supports the first color depth. [11] AMOLED display device with: a display screen that features AMOLED-based pixels; a data processor that processes image data from a video source and Compensation data processed by a compensation unit and outputs compensated image data, where the image data has an initial color depth, and the compensation data and the compensated image data have a second color depth that is greater than the first color depth; a single frame rate control module that sets the compensated image data to the first color depth; a timing controller that generates a timing control signal corresponding to an output signal from the frame rate control module; a driver that drives the display screen according to the timing control signal; a display measurement module that measures the homogeneity of the display screen; and a compensation unit that generates compensation data for the second color depth according to the measurement result of the display measurement module and outputs it to the data processor; and where the first color depth is 8 bits; where the second color depth is 10 bits; wherein the compensation unit has a look-up table; and where the display screen supports the first color depth.

Images