Brightness correction method and display system

Abstract

A brightness correction method and display system are disclosed. The brightness correction method includes the following steps: receiving temperature data from a display panel; obtaining a gamma correction list; generating multiple gamma adjustment points based on the temperature data and the gamma correction list; generating a gamma correction curve based on the gamma adjustment points; and displaying an image on the display panel according to the gamma correction curve.

Description

Technical Field

[0001] This disclosure relates to a brightness correction method, and more particularly to a brightness correction method and display system for a display panel. Background Technology

[0002] In modern display panels, the size of light-emitting elements is gradually shrinking, enabling many advantages such as higher resolution, wider color gamut, lower power consumption, and a wider operating temperature range. However, the brightness of smaller light-emitting elements is more prone to decrease with increasing temperature. Therefore, how to compensate for the decrease in brightness of display panels due to temperature is an important issue in this field. Summary of the Invention

[0003] This disclosure provides a brightness correction method, which includes the following steps: receiving temperature data from a display panel; obtaining a gamma correction list; generating multiple gamma adjustment points based on the temperature data and the gamma correction list; generating a gamma correction curve based on these gamma adjustment points; and displaying an image on the display panel according to the gamma correction curve.

[0004] This disclosure provides a display system including a display panel, a temperature sensor, and processing circuitry. The temperature sensor senses temperature data from the display panel. The processing circuitry is electrically coupled to the display panel and the temperature sensor. The processing circuitry generates a plurality of gamma adjustment points based on the temperature data and a gamma correction list. These gamma adjustment points are output to the display panel, wherein the display panel generates a gamma correction curve based on the gamma adjustment points to display a screen according to the gamma correction curve.

[0005] This disclosure provides a brightness correction method, which includes the following steps: receiving temperature data of a display panel; mapping the temperature data to a plurality of adjusted time intervals corresponding to a plurality of sub-pixels; correcting a plurality of light emission cycles of the sub-pixels of the display panel according to the adjusted time intervals respectively, to generate a plurality of corrected light emission cycles; and displaying an image by the display panel according to the corrected light emission cycles of the sub-pixels. Attached Figure Description

[0006] To make the above and other objects, features, advantages and embodiments of this disclosure more apparent and understandable, the accompanying drawings are described below:

[0007] Figure 1 This is a schematic diagram of a display system according to some embodiments of the present disclosure.

[0008] Figure 2 This is a schematic diagram of a display panel according to some embodiments of the present disclosure.

[0009] Figure 3A This is a schematic diagram illustrating the changes in brightness and temperature over time according to some embodiments of the present disclosure.

[0010] Figure 3B This is a schematic diagram showing the percentage decrease in brightness at different temperatures according to some embodiments of the present disclosure.

[0011] Figure 4A This is a flowchart of a brightness correction method according to some embodiments of the present disclosure.

[0012] Figure 4B According to some embodiments of this disclosure Figure 4A A flowchart of step S210 of the brightness correction method.

[0013] Figure 4C According to some embodiments of this disclosure Figure 4B The flowchart of step S212.

[0014] Figure 5A This is a schematic diagram of an adjusted gamma curve based on some embodiments of the present disclosure.

[0015] Figure 5B This is a schematic diagram of gamma-temperature curves according to some embodiments of the present disclosure.

[0016] Figure 6A This is a schematic diagram of the current gamma curve and the corrected gamma curve according to some embodiments of this disclosure.

[0017] Figure 6B This is a schematic diagram of a pixel circuit according to some embodiments of the present disclosure.

[0018] Figure 7 This is a flowchart of a brightness correction method according to some embodiments of the present disclosure.

[0019] Figure 8A This is a schematic diagram of an adjusted gamma curve based on some embodiments of the present disclosure.

[0020] Figure 8B This is a schematic diagram of the emission period correction parameters at different temperatures according to some embodiments of the present disclosure.

[0021] Figure 9 This is a schematic diagram of a pixel circuit according to some embodiments of the present disclosure.

[0022] Figure 10 This is a schematic diagram showing the change in brightness of a display panel with temperature before and after correction, according to some embodiments of the present disclosure.

[0023] Figure 11A Figure 11B is a schematic diagram of the architecture of a display system according to some embodiments of the present disclosure.

[0024] Figure 12AThis is a functional schematic diagram of a display system according to some embodiments of the present disclosure.

[0025] Figure 12B This is a schematic diagram of the architecture of a display system according to some embodiments of the present disclosure.

[0026] Figure 13 This is a schematic diagram of a display system and display panel according to some embodiments of the present disclosure.

[0027] Explanation of reference numerals in the attached figures:

[0028] To make the above and other objects, features, advantages and embodiments of this disclosure more apparent and understandable, the appended symbols are explained as follows:

[0029] 100, 100a, 100b, 400: Display system

[0030] 105: Temperature sensor

[0031] 110: Display panel

[0032] 112: Controller

[0033] 114: Source Driver

[0034] 116: Gate driver

[0035] 118: Pixel Array

[0036] 122: Processing Circuit

[0037] 124: Memory

[0038] 200, 300: Brightness Correction Methods

[0039] 500: Optical Inspection System

[0040] 510: Optical measuring equipment

[0041] 520: Processing Circuit

[0042] 530: Programming device

[0043] PIX, PIXa, PIXb: Pixel circuits

[0044] TempDATA: Temperature data

[0045] CalTAB: Calibration Table

[0046] CalParm: Correction parameter

[0047] G1~Gx,GL: Gate lines

[0048] D1~Dy,DL: Data cable

[0049] TC: Temperature

[0050] LC, Ical, Iori: Brightness

[0051] G25, G35, G45, G55, G65: Adjusted Gamma Curve

[0052] F 63 ,F 127 ,F 159 ,F 191 ,F 255 Gamma-temperature function

[0053] G: Gamma curve

[0054] G': Gamma correction curve

[0055] Gw25: Standard Gamma Curve

[0056] Gw35, G45: Adjusted Gamma Curve

[0057] EM25, EM35, EM45: Luminescence Cycle

[0058] Td: Driving transistor

[0059] T11, T21, T22: Transistors

[0060] L1: Light-emitting element

[0061] Cst: Capacitor

[0062] AA: Display area

[0063] FPC: Flexible Printed Circuit Board

[0064] TS: Switching Transistor

[0065] EM: Light emission control signal

[0066] VSS: System low voltage terminal

[0067] VDD, VDD_PAM, VDD_PWM: System high voltage terminals

[0068] Vdata25, Vdata45: Data voltage

[0069] Vdata_PAM, Vdata_PWM: Data voltage

[0070] Vdata_PWM25, Vdata_PWM45: Data voltage

[0071] Ida, Ida25, Ida45, Idb, Idb25, Idb45: Drive current

[0072] S210~S215, S220, S230, S235, S240, S250: Steps

[0073] S260, S270: Steps

[0074] S305, S310, S320, S330, S340, S345, S350: Steps

[0075] S360, S370: Steps Detailed Implementation

[0076] The following is a detailed description of embodiments with reference to the accompanying drawings. However, the provided embodiments are not intended to limit the scope of this disclosure, and the description of the structure's operation is not intended to limit its execution order. Any structure resulting from the recombination of elements and producing an apparatus with equivalent technical effects is within the scope of this disclosure. Furthermore, the illustrations are for illustrative purposes only and are not drawn to their original dimensions. For ease of understanding, the same or similar elements will be designated with the same symbols in the following description.

[0077] Unless otherwise specified, the terms used throughout this specification and claims generally have their ordinary meaning in the context of this art, the disclosure, and the specific content. Furthermore, the terms “comprising,” “including,” “having,” “containing,” etc., as used herein, are open-ended terms, meaning “including but not limited to.” Additionally, the term “and / or” as used herein includes any one or more of the related listed items and all combinations thereof.

[0078] Please see Figure 1 , Figure 1 This is a schematic diagram of a display system 100 according to some embodiments of the present disclosure. Figure 1 As shown, the display system 100 includes a temperature sensor 105, a processing circuit 122, a memory 124, and a display panel 110. In some embodiments, the display system 100 may be implemented by an electronic device having a display panel, such as a laptop computer, mobile device, desktop computer, or other electronic device. In other embodiments, the display system 100 may be implemented by a display device, and this disclosure is not limited thereto.

[0079] In some embodiments, the temperature sensor 105 may be implemented as a contact sensor, and the sensing portion of the temperature sensor 105 may be located adjacent to the display panel 110, for example, on the upper side, lower side, or outer edge of the display panel 110, to detect the temperature data TempDATA of the display panel 110. In other embodiments, the temperature sensor 105 may be implemented as a non-contact sensor, and this disclosure is not limited thereto.

[0080] In some embodiments, the memory 124 stores a calibration table CalTAB that corrects the gamma curve and / or emission period of the display panel 110 based on temperature changes of the display panel 110. In some embodiments, before leaving the factory, an optical inspection system (not shown) performs the calibration. Figure 1 The display panel 110 will be gamma calibrated to obtain the aforementioned calibration table CalTAB, and the calibration table CalTAB will be written to the memory 124 through a one-time programming.

[0081] In some embodiments, the processing circuitry 122 may be implemented by circuitry / components on the motherboard of a system, such as a laptop, mobile device, desktop computer, or other electronic device. In some embodiments, the processing circuitry 122 is electrically connected to the memory 124 to retrieve the aforementioned calibration table CalTAB from the memory 124. In some embodiments, the processing circuitry 122 receives temperature data TempDATA from the temperature sensor 105 of the display panel 110 and retrieves the calibration table 126 from the memory 124, thereby outputting a calibration parameter CalParm based on the temperature data TempDATA of the display panel 110 and the calibration table 126.

[0082] In some embodiments, the display panel 110 receives a correction parameter CalParm from the self-processing circuit 122 to correct the display brightness according to the correction parameter CalParm. In some instances, the display panel 110 includes a controller 112, a source driver 114, a gate driver 116, and a pixel array 118. In some embodiments, the pixel array 118 is implemented as a light-emitting diode (LED) pixel array. In some embodiments, the LED pixel array may be implemented as a micro LED array. In some embodiments, the pixel array 118 may be implemented as an LED array, a sub-millimeter LED array, or an LED array of other sizes, and this disclosure is not limited thereto.

[0083] Please see Figure 1 as well as Figure 2 , Figure 2 This is a schematic diagram of a display panel 110 according to some embodiments of the present disclosure. Figure 2As shown, the pixel array 118 includes a plurality of pixel circuits (PIX), each of which includes a light-emitting element. In some embodiments, the light-emitting element is implemented using a micro-light-emitting diode (LED), and the display panel 110 can be understood as a micro-light-emitting diode display panel. In other embodiments, the light-emitting element may be implemented using LEDs of other sizes. In some embodiments, the gate driver 116 is electrically coupled to pixel circuits (PIX) located in the same pixel column via one of the gate lines G1 to Gx, thereby scanning the pixel array 118 column by column. In some embodiments, the source driver 114 is electrically coupled to pixel circuits (PIX) located in the same pixel row via one of the data lines D1 to Dy, so as to transmit data voltage to the corresponding pixel circuit (PIX) via the data lines D1 to Dy, thereby setting the luminous brightness of the light-emitting element in each pixel circuit (PIX).

[0084] Please refer to pages 1 through 2020. Figure 3A . Figure 3A This is a schematic diagram illustrating the changes in brightness (LC) and temperature (TC) of a display panel over time according to some embodiments of the present disclosure. In some embodiments, the micro-light-emitting diode panel has a wider operating temperature range compared to liquid crystal panels and organic light-emitting diode panels. Temperature changes have a greater impact on the luminous brightness of light-emitting elements with smaller dimensions, such as... Figure 3A As shown, the brightness LC of the miniature LED panel decreases to some extent as the operating time increases. Furthermore, since the brightness of red, blue, and green LEDs decreases at different rates with temperature changes, this further contributes to color shift.

[0085] For example, in the initial operating state, the red, green, and blue sub-pixels have brightness values ​​of 100, 210, and 74 nits, respectively. As the display panel continues to operate and its temperature rises, the brightness of the red, green, and blue sub-pixels, under the same settings, decreases to 70, 200, and 70 nits, respectively. This varying degree of brightness reduction in the red, green, and blue pixels causes color shift in that pixel or the entire display screen. As another example, under a preset screen, the coordinates of the display panel in the CIE XY color space are (0.3, 0.313). Under the same preset screen, as the temperature of the display panel increases, its coordinates in the CIE XY color space shift to (0.27, 0.328), causing color shift in the micro-LED panel as the temperature increases with operating hours.

[0086] Please see Figure 3B , Figure 3B This is a schematic diagram illustrating the percentage decrease in brightness of a display panel at different temperatures according to some embodiments of the present disclosure. Figure 3BAs shown, as the display panel temperature increases, the brightness decrease ratio in high-brightness mode (e.g., 1200 nits) and normal mode (e.g., 350 nits) gradually increases, and the decrease ratios are approximately the same at the same temperature. Figure 3B It can be inferred that the decreasing brightness trend of the display panel is strongly correlated with temperature. Therefore, please refer to... Figure 1 as well as Figure 4A , Figure 4A This is a flowchart of a brightness correction method 200 according to some embodiments of the present disclosure.

[0087] like Figure 4A As shown, the brightness correction method 200 includes steps S210 to S270. Steps S210 to S270 can be divided into step S210 in the data establishment phase and steps S220 to S270 in the operation phase. In some embodiments, step S210 in the data establishment phase can be performed before the product leaves the factory, and steps S220 to S270 in the operation phase can be performed when the product is used. In some embodiments, steps S220 to S250 of the brightness correction method 200 are performed by the processing circuit 122, and steps S260 to S270 are performed by the display panel 110. The brightness correction method 200 of the display panel 110 in the data establishment phase includes step S210. In step S210, a gamma correction list is established.

[0088] For a better understanding of how to create a gamma correction list, please also refer to... Figure 1 , Figure 4A , Figure 4B , Figure 5A as well as Figure 5B . Figure 4B According to some embodiments of this disclosure Figure 4A A flowchart of step S210 of the medium brightness correction method 200. Figure 4B According to some embodiments of this disclosure Figure 4A A flowchart of step S210 of the brightness correction method. Figure 5A This is a schematic diagram of an adjusted gamma curve based on some embodiments of the present disclosure. Figure 5B This is a schematic diagram of gamma-temperature profiles according to some embodiments of the present disclosure. Figure 4B As shown, step S210 includes S211 and S212.

[0089] The data setup stage of the brightness correction method 200 applicable to a display panel 110 with pulse amplitude modulation technology includes steps S211 to S215.

[0090] In step S211, when the temperature of the display panel 110 rises and sequentially reaches multiple temperatures, an initial gamma curve is adjusted according to the multiple decreases of the display panel 110 at these grayscale values ​​to generate multiple adjusted gamma curves G25 to G65 corresponding to these temperatures.

[0091] For example, if the temperature of the display panel 110 is 25°C, the brightness of the display panel 110 at different input grayscale values ​​is recorded, and the initial gamma curve is adjusted according to the decrease ratio of the multiple brightness values ​​to make the display panel 110 reach the preset brightness, thereby obtaining the adjusted gamma curve G25. Thus, as the temperature of the display panel 110 gradually increases to other temperatures, such as 35°C, 45°C, 55°C, and 65°C, adjusted gamma curves G35 to G65 corresponding to these temperatures can be obtained. Figure 5A As shown. In some embodiments, the gamma parameter can be adjusted at other temperatures to obtain different numbers of adjusted gamma curves, but this disclosure is not limited thereto.

[0092] In step S212, the adjusted gamma curves G25 to G65 corresponding to the temperatures are converted to gamma-temperature functions C63 to C255 corresponding to the grayscale values ​​to generate a gamma correction list. Step S212 includes steps S213 to S215, as follows: Figure 4C As shown.

[0093] In step S213, multiple reference points are selected from the adjusted gamma curves G25 to G65 corresponding to the respective temperatures. For example, gamma data at grayscale 255 is selected from the adjusted gamma curves G25 to G65 to generate reference points (255, Dn1) to (255, Dn5), and so on. Correspondingly, gamma data at other grayscale values ​​are selected from the adjusted gamma curves G25 to G65 to generate reference points (63, D11) to (63, D15).

[0094] In step S214, the reference points are transformed to convert the grayscale axis to the temperature axis, resulting in multiple transformed reference points. For example, since the adjusted gamma curves G25 to G65 were obtained at temperatures ranging from 25°C to 65°C, the grayscale values ​​of the reference points (255, Dn1) to (255, Dn5) selected from the adjusted gamma curves G25 to G65 are converted to temperature values, thus obtaining the transformed reference points (25, Dn1), (35, Dn2), (45, Dn3) to (65, Dn5), and so on. Correspondingly, the grayscale values ​​of the reference points (63, D11) to (63, D15) are converted to temperature values, thus obtaining the transformed reference points (25, D11) to (65, D15).

[0095] In step S215, the transformed reference points are fitted to form the gamma-pair temperature functions. For example, curve fitting is performed on the transformed reference points (25, Dn1) to (65, Dn5) to generate the gamma-pair temperature function F. 255 The gamma-temperature function F 255 This corresponds to a grayscale value of 255. Similarly, curve fitting is performed on the transformed reference points (25, D11) to (65, D15) to generate the gamma-temperature function F. 63 The gamma-temperature function F 63 The corresponding grayscale value is 63.

[0096] Thus, the gamma pair temperature function F corresponding to grayscale values ​​of 63, 127, and 159–255 can be obtained respectively. 63 F 127 F 159 ~F 255 In some embodiments, the number of gamma-to-temperature functions F63 to F255 may be 13. In other embodiments, the gamma correction list may contain more or fewer gamma-to-temperature functions.

[0097] In some embodiments, the aforementioned curve fitting can be performed by curve fitting of a linear, quadratic, or polynomial equation to obtain the corresponding power of the gamma-level temperature function F. 63 ~F 255 This allows for a better match with the transformed reference point. In some embodiments, the parameters of each term in the gamma-temperature functions F63, F127, and F159–F255 can be stored in the corresponding fields of the gamma correction list, thereby simplifying the function expression. In some embodiments, the gamma-temperature function F 63 ~F 255 It is achieved by fitting a cubic equation, where the gamma correction list is shown in Table 1 below.

[0098]

[0099] Table 1

[0100] For example, the gamma-to-temperature function corresponding to a grayscale value of 255 is F255(x) = -2.25x. 3 +23.75x 2 -36 x +657.4, as shown in Table 1. This completes the establishment of the gamma correction list. In some instances, the parameters of the adjusted gamma curves G25–G65 and the gamma-temperature functions F63–F255 in the gamma correction list can be written to memory 124 via one-time programmable (OTP).

[0101] It is worth noting that the aforementioned gamma correction list is a single-color gamma correction list, such as a red, blue, or green gamma correction list. Therefore, by repeating the aforementioned steps S211 to 215, gamma correction lists for all colors can be obtained, thereby enabling brightness compensation for red, blue, and green LEDs whose brightness decreases to different degrees at the current temperature.

[0102] The operation phase of the brightness correction method 200 applicable to the display panel 110 with pulse amplitude modulation technology includes steps S220 to S270.

[0103] In step S220, a temperature data TempDATA from a display panel 110 is received. The processing circuit 122 receives the current temperature data TempDATA from the temperature sensor 105.

[0104] In step S230, it is determined whether the temperature data TempDATA is higher than a threshold. The threshold can be set at 25°C, 30°C, 35°C, or other suitable temperatures, and this disclosure is not limited thereto. If the temperature data TempDATA is lower than the threshold, step S235 is executed, controlling the display panel 110 to operate according to an original gamma curve. The original gamma curve operation can be, for example, an adjusted gamma curve G25 corresponding to 25°C. If the temperature data TempDATA is higher than the threshold, step S240 is executed to obtain the gamma correction list.

[0105] In step S250, multiple gamma adjustment points are generated based on the temperature data TempDATA and the gamma correction list. Specifically, the temperature data TempDATA is substituted into the gamma-temperature function F63 to F255 in the gamma correction list to generate the gamma adjustment points at the corresponding gray levels.

[0106] For example, the temperature data TempDATA sensed by the display panel 110 is T℃, where "T" represents an arbitrary constant. The processing circuit 122 substitutes the temperature data TempDATA of T℃ into the gamma-pair temperature function F, which corresponds to grayscale levels 63 to 255. 63 (x)~F 255 (x) is used to obtain the corrected gamma data F corresponding to grayscale levels 63–255. 63 (T)~F 255 (T), and form the gamma adjustment point (63, F) 63 (T))~(255,F 255(T)). In some embodiments, the number of gamma adjustment points may be 13 or other numbers that meet the requirements of the display panel 110 for gamma adjustment points. In some embodiments, the processing circuit 122 outputs gamma adjustment points to the display panel 110. In some embodiments, the gamma adjustment points generated based on the current temperature data TempDATA correspond to Figure 1 The correction parameter CalParm in the text.

[0107] In step S260, based on these gamma adjustment points (63, F) 63 (T))~(255,F 255 (T)) Corrects a gamma curve to generate a gamma correction curve. In some embodiments, the display circuit 110 adjusts according to (63, F) 63 (T))~(255,F 255 (T)) Correct the current gamma curve G to generate a gamma correction curve G', such as Figure 6A As shown. In other embodiments, the display panel 110 uses interpolation to expand the values ​​of the gamma adjustment points (63, F63(T)) to (255, F255(T)) to generate the gamma correction curve G'.

[0108] In step S270, the display panel 110 displays an image according to the gamma correction curve G'. For example, the display panel 110 converts the input image data into a data voltage according to the gamma correction curve G', so that each pixel in the pixel array 118 emits light according to the corresponding data voltage.

[0109] Please see Figure 1 , Figure 2 , Figure 6A as well as Figure 6B , Figure 6B This is a schematic diagram of a pixel circuit PIXa according to some embodiments of the present disclosure. In some embodiments, the brightness correction method 200 is applied to a display panel 110 employing pulse amplitude dimming functionality. In such a case, each of the pixel circuits PIXa of the pixel array 118 can be... Figure 6B The pixel circuit PIXa is implemented.

[0110] like Figure 6BAs shown, the pixel circuit PIXa includes a driving transistor Td, a light-emitting element L1, a transistor T11, and a capacitor Cst. Architecturally, the driving transistor Td and the light-emitting element L1 are electrically coupled between the system high voltage terminal VDD and the system low voltage terminal VSS. In some embodiments, the light-emitting element L1 can be implemented using a miniature light-emitting diode or a light-emitting diode of other sizes. During the data setting phase, the gate terminal of transistor T11 receives a scan signal from the gate line GL to transmit the voltage on the data line DL to the gate terminal of the driving transistor Td. This allows the driving transistor Td to control the pulse amplitude of the driving current Ida according to the potential of its gate terminal during light emission, thereby compensating for the decrease in brightness of the light-emitting element L1 caused by temperature increases.

[0111] For example, under the same input grayscale, if the temperature of the display panel 110 is 25°C, the input grayscale value is converted into a data voltage Vdata25 according to the original gamma curve G; if the temperature of the display panel 110 is 45°C, the input grayscale value is converted into a data voltage Vdata45 according to the gamma correction curve G'. Therefore, under the same input grayscale, the pixel circuit PIXa provides a lower amplitude drive current Ida25 at lower temperatures and a higher amplitude drive current Ida45 at higher temperatures. In this way, the pixel circuit PIXa can compensate for the brightness of the light-emitting element L1 by controlling the pulse amplitude of the drive current Ida at different temperatures.

[0112] Please refer to Figure 1 , Figure 2 , Figure 7 . Figure 7 This is a flowchart of a brightness correction method 300 according to some embodiments of the present disclosure. In some embodiments, the brightness correction method 300 is applicable to a display system 100 of a display panel 110 having pulse width modulation functionality.

[0113] To better understand how to correct the brightness of the display panel 110, which uses pulse width modulation for dimming, at different temperatures, please refer to [link to relevant documentation]. Figure 8A as well as Figure 8B . Figure 8A This is a schematic diagram of a standard gamma curve Gw25 and adjusted gamma curves Gw35 to Gw45 according to some embodiments of this disclosure. Figure 8B This is a schematic diagram showing the luminous emission cycles EM25 to EM45 at different temperatures according to some embodiments of this disclosure. The adjusted gamma curves Gw35 to Gw45 are gamma curves obtained by calibrating the display panel 110 at different temperatures to achieve the desired brightness.

[0114] like Figure 8AAs shown, the adjusted gamma curve Gw35 of display panel 110 at 35°C has a brightness increase of a% compared to the standard gamma curve Gw25 at all gray levels, and the adjusted gamma curve Gw45 of display panel 110 at 45°C has a brightness increase of (a+b)% compared to the standard gamma curve Gw25 at all gray levels. Since gamma data is proportional to data voltage, the data voltage controls the pulse width of the pulse current. This means that at the same gray level, the pulse width of the driving current at 35°C needs to be a% greater than that at 25°C to achieve the same brightness. Similarly, the pulse width of the driving current at 45°C needs to be (a+b)% greater than that at 25°C to achieve the same brightness.

[0115] In such a situation, as the temperature of the display panel 110 increases, a longer light-emitting cycle is required to accommodate the larger pulse width of the driving current at high grayscale in order to compensate for the decrease in brightness with temperature.

[0116] like Figure 8B As shown, the luminescence period of EM35 at 35°C was adjusted to be a% longer than that of EM25 at 25°C. The luminescence period of EM45 at 45°C was adjusted to be (a+b)% longer than that of EM25 at 25°C.

[0117] Therefore, the brightness correction method 300 adjusts the length of the light emission cycle and maintains the duty cycle of the adjusted pulse width in the adjusted light emission cycle consistent with the duty cycle of the pulse width before correction in the standard light emission cycle, thereby compensating for the brightness of the display panel 110 that achieves dimming function by pulse width modulation.

[0118] Please see Figure 1 as well as Figure 7 The brightness correction method 300 includes steps S305 to S370. Steps S305 to S370 can be divided into steps S305 to S320 in the data establishment phase and steps S330 to S370 in the operation phase. In some embodiments, steps S305 to S320 in the data establishment phase can be performed before the product leaves the factory, and steps S330 to S370 in the operation phase can be performed when the product is used. In some embodiments, steps S330 to S360 of the brightness correction method 300 are performed by the processing circuit 122, and step S370 is performed by the display panel 110.

[0119] The data setup stage of the brightness correction method 300 applicable to a display panel 110 with pulse width modulation technology includes steps S305 to S320.

[0120] In step S305, multiple brightness values ​​of the display panel 110 at multiple temperatures are received. For example, during the temperature rise of the display panel 110, multiple brightness values ​​are measured by an optical detection system (not shown). Figure 1 Optical measuring equipment (not shown) Figure 1 The brightness value of the display panel 110 under a preset screen (e.g., a white screen) is sensed and transmitted to the processing circuit 122. In some embodiments, the brightness value of the display panel 110 at multiple temperatures can be distinguished into red light, green light, and blue light brightness values. For example, the red light, green light, and blue light brightness values ​​of the display panel 110 before correction at multiple temperatures are shown in Table 2 below.

[0121]

[0122] Table 2

[0123] In step S310, based on the brightness values ​​and the standard brightness values, a plurality of brightness reduction ratios of the display panel 110 at the given temperatures are calculated. Specifically, a brightness value is subtracted from a standard brightness value to calculate the difference, and the difference is divided by the standard brightness value to obtain a reduction ratio.

[0124] For example, before calibration, the red light brightness of display panel 110 at 45°C is 173.6 nits. If the red light brightness of display panel 110 at 25°C (230 nits) is set to the standard brightness value, the decrease is equal to ((230-176.3) / 230) = 24.5%. Similarly, the decrease in red light brightness of display panel 110 at 45°C is equal to ((230-120) / 230) = 47.8%. And so on. As another example, the green light brightness of display panel 110 at 45°C is 640.7 nits. If the green light brightness of display panel 110 at 25°C (673 nits) is set to the standard brightness value, the decrease is equal to ((673-640.7) / 640.7) = 4.8%. And so on. Thus, the processing circuit 122 obtains the brightness reduction ratio of red, green and blue light of the display panel 110 at multiple temperatures.

[0125] In step S320, the standard time intervals are adjusted according to the brightness decrease ratios to generate adjusted time intervals, and a lookup table is formed based on the temperatures and the adjusted time intervals. Specifically, the adjusted time intervals can be represented by the following formula.

[0126] e' = e / (1-R)

[0127] In the above formula, the adjusted time interval is represented by e', the standard time interval is represented by e, and the decrease ratio is represented by R.

[0128] In this way, the adjusted time intervals of the red, green, and blue sub-pixels at each temperature can be obtained, and a lookup table can be formed based on the adjusted time intervals, as shown in Table 3 below.

[0129]

[0130] Table 3

[0131] In some embodiments, the lookup table described above can be written to the memory 124 via one-time programmable (OTP) so that it can be retrieved by the processing circuit 122 during the operation of the display panel 110.

[0132] The operation phase of the brightness correction method 300 applicable to the display panel 110 with pulse width modulation technology includes steps S330 to S370.

[0133] In step S330, a temperature data TempDATA from a display panel 110 is received. The processing circuit 122 receives the current temperature data TempDATA from the temperature sensor 105.

[0134] In step S340, it is determined whether the temperature data TempDATA is higher than a threshold. The threshold can be implemented using 25°C, 30°C, 35°C, or other suitable temperatures, and this disclosure is not limited thereto. If the temperature data TempDATA is lower than the threshold, step S345 is executed, controlling the display panel 110 to operate according to the original light emission cycle. The original light emission cycle can be, for example, the red, green, and blue light emission cycles corresponding to 25°C. If the temperature data TempDATA is higher than the threshold, step S350 is executed.

[0135] In step S350, the temperature data TempDATA is mapped to multiple adjusted time intervals corresponding to multiple sub-pixels. Specifically, the processing circuit 122 maps the temperature data TempDATA to the adjusted time intervals of the red, green, and blue sub-pixels according to the aforementioned lookup table. For example, if the temperature data TempDATA is 45°C, the adjusted time intervals for the red, green, and blue sub-pixels are 26.5 μs, 36.8 μs, and 20.4 μs, respectively. In some embodiments, the aforementioned adjusted time intervals generated based on the current temperature data TempDATA correspond to... Figure 1 The correction parameter CalParm in the text.

[0136] In step S360, the multiple light-emitting periods of the sub-pixels of the display panel 110 are corrected according to the adjusted time intervals to generate multiple corrected light-emitting periods. For example, if the light-emitting periods of the red, green, and blue sub-pixels of the display panel 110 before correction are 20.0 μs, 35 μs, and 18 μs, respectively, the adjusted time intervals of the aforementioned sub-pixels of each color are updated to the light-emitting periods of the sub-pixels of each color in the display panel 110 to generate corrected light-emitting periods of the red, green, and blue sub-pixels, for example, 26.5 μs, 36.8 μs, and 20.4 μs.

[0137] In step S370, the display panel 110 displays an image based on the corrected emission periods of the sub-pixels. For example, the display panel 110 displays an image based on the corrected emission periods of the red, green, and blue sub-pixels, such as 26.5μs, 36.8μs, and 20.4μs.

[0138] In some embodiments, the display panel 110 further corrects the standard gamma curve based on the ratio of the corrected emission period to the original emission period of the red, green, and blue sub-pixels, and displays the image based on the gamma correction curve and the corrected emission period. Specifically, the ratio of the gamma correction curve to the original gamma curve is equal to the ratio of the corrected emission period to the original emission period.

[0139] Thus, the corrected brightness of the red, green, and blue light of the display panel 110 is shown in Table 4 below.

[0140]

[0141]

[0142] Table 4

[0143] Thus, as shown in Table 4, steps S330 to S370 can compensate the brightness of each color of light on the display panel 110 to the standard brightness (for example, the standard brightness of red light, green light and blue light are 230.0 nits, 673.0 nits and 97.0 nits, respectively).

[0144] See Figure 1 , Figure 2 , Figure 7 as well as Figure 9 , Figure 9 This is a schematic diagram of a pixel circuit PIXb according to some embodiments of the present disclosure. In some embodiments, Figure 2 Each of the pixel circuits (PIX) in the pixel array 118 can be made by Figure 9The pixel circuit implementation. In some embodiments, the pixel circuit PIXb includes a pulse amplitude modulation circuit PAM, a pulse width modulation circuit PWM, transistors T21 and T22, a light-emitting element L1, and a switching transistor TS. The pulse amplitude modulation circuit PAM and the pulse width modulation circuit PWM are electrically coupled to the system high voltage terminals VDD_PAM and VDD_PWM, respectively. The pulse amplitude modulation circuit PAM controls the pulse amplitude of the drive current Idb according to the data voltage Vdata_PAM.

[0145] The pulse width modulation (PWM) circuit controls the pulse width of the drive current Idb based on the data voltage Vdata_PWM. In some embodiments, during data setting, the data voltage Vdata_PWM is transmitted to the operating node in the PWM circuit. During illumination, the sweep signal SWEEP gradually pulls down the potential of the operating node in the PWM circuit to control the timing at which the potential of the system high-voltage terminal VDD_PWM is transmitted to the switching transistor TS. When the potential of the system high-voltage terminal VDD_PWM is transmitted to the switching transistor TS, the switching transistor TS is turned off, thereby controlling / adjusting the pulse width of the drive current Idb according to the data voltage Vdata_PWM.

[0146] In some embodiments, transistors T21 and T22 are used to receive the light emission control signal EM. In some instances, the duration of the light emission control signal EM at the enable level can be understood from the duration of the light emission cycle.

[0147] For example, under the same input grayscale, if the temperature of the display panel 110 is 25°C, the input grayscale value is converted into a data voltage Vdata_PWM25 and an original emission period EM25 according to the original gamma curve; if the temperature of the display panel 110 is 45°C, the input grayscale value is converted into a data voltage Vdata_PWM45 according to the gamma correction curve, and the temperature of 45°C is mapped to the required corrected emission period EM45 according to a lookup table. Therefore, under the same input grayscale, the pixel circuit PIXb provides a drive current Idb25 with a smaller pulse width at lower temperatures and a drive current Idb45 with a larger pulse width at higher temperatures. In this way, the pixel circuit PIXb can compensate for the brightness of the light-emitting element L1 by controlling the pulse width of the drive current Idb at different temperatures.

[0148] Please see Figure 10 , Figure 10 This is a schematic diagram showing the brightness of a display panel 110 before and after calibration as a function of temperature, according to some embodiments of this disclosure. Figure 10As can be seen, without calibration, the brightness Iori of the display panel 110 decreases significantly with increasing temperature. After calibration through steps S330-370, the brightness Ical of the display panel 110 is not affected by temperature changes and exhibits a fairly stable performance.

[0149] Please see Figure 11A as well as Figure 11B . Figure 11A Figure 11B is a schematic diagram of the architecture of display systems 100a and 100b according to some embodiments of the present disclosure. Figure 11A In this configuration, a temperature sensor 105 can be mounted on the display panel 110 and transmits temperature data (TempDATA) to the processing circuit 122 of the system terminal 120. Figure 11B In this system, temperature sensor 105 can be located at system end 120 and used to sense temperature data TempDATA of display panel 110.

[0150] Please see Figure 2 Figures 4A to 4C Figure 7 as well as Figure 12A . Figure 12A This is a functional schematic diagram of a display system 400 according to some embodiments of the present disclosure. Compared to Figure 1 The display system 100 in the middle, Figure 12A In the display system 400, the brightness of the display panel 110 is compensated by the controller 112 based on temperature data TempDATA and the calibration table CalTAB. The controller 112 is electrically coupled to the temperature sensor 105 to receive the temperature data TempDATA, and the controller 112 is electrically coupled to the memory 124 to retrieve the calibration table CalTAB.

[0151] exist Figure 12A In the embodiments, the controller 112 executes steps S220 to S270 of the brightness correction method 200 in Figures 4A to 4C, or executes... Figure 7 Steps S330 to S370 of the brightness correction method 300. Therefore, this disclosure is not limited to the circuits that perform brightness correction methods 200 or 300.

[0152] Please see Figure 12A as well as Figure 12B . Figure 12B This is a schematic diagram of the architecture of a display system 400 according to some embodiments of the present disclosure. Figure 12A as well as Figure 12B In one embodiment, the controller 112 and the temperature sensor 105 may be disposed on a flexible printed circuit board (FPC), thereby the controller 112 controls the pixel circuit located in the display area AA through the wiring of the flexible printed circuit board (FPC).

[0153] Please see Figure 1 as well as Figure 13 , Figure 13 This is a schematic diagram of an optical detection system 500 and a display panel 110 according to some embodiments of the present disclosure. In some embodiments, steps S211 to S215 in the brightness correction method 200 and steps S305 to S320 in 300 can be derived by... Figure 13 The optical inspection system 500 performs the operation. The optical inspection system 500 includes an optical measurement device 510 for measuring the brightness of the display panel 110. The processing circuit 520 performs steps S211-S215 or steps S305-S320. The programming device 530 performs a one-time programming of the memory 124 to write the calibration table CalTAB into the memory 124. In some embodiments, the calibration table CalTAB corresponds to the aforementioned gamma calibration list. In some embodiments, the calibration table CalTAB corresponds to the aforementioned lookup table.

[0154] In other embodiments, steps S211-S215 in brightness correction method 200 and steps S305-S320 in 300 can also be performed by... Figure 1 The processing circuit 122 in the middle executes the process, but this disclosure is not limited thereto.

[0155] In some embodiments, the aforementioned processing circuitry may be a central processing unit, microprocessor, graphics processor, field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), or other hardware device suitable for retrieving or executing instructions stored in memory.

[0156] In some embodiments, the aforementioned memory may be implemented by an electrical, magnetic, optical storage device or other storage device for storing instructions or data. In some embodiments, the aforementioned memory may be implemented by volatile memory or non-volatile memory. In some embodiments, the aforementioned memory may be implemented by random access memory (RAM), dynamic random access memory (DRAM), magnetoresistive random access memory (MRAM), phase-change random access memory (PCRAM) or other storage devices.

[0157] In summary, if the display panel 110 employs pulse amplitude modulation (PWM) dimming technology, this disclosure provides a brightness correction method 200 to compensate for the different brightness reduction rates of each grayscale level of the display panel 110 at the current temperature. Furthermore, by executing steps S240 to S270 on the gamma data corresponding to different color sub-pixels, the different brightness reduction ratios of each color light-emitting element can be compensated simultaneously. If the display panel 110 employs pulse width modulation (PWM) dimming technology, this disclosure provides a brightness correction method 300 to compensate for the different brightness reduction ratios of each color light-emitting element of the display panel 110 at the current temperature. Moreover, the brightness correction methods 200 and 300 proposed in this disclosure can effectively compensate for the significant decrease in brightness of the display panel 110 as the temperature rises.

[0158] Although this disclosure has been described above with reference to embodiments, it is not intended to limit this disclosure. Any person skilled in the art can make various changes and modifications without departing from the concept and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the claims.

Claims

1. A brightness correction method, comprising: In a data establishment phase, as the temperature of the display panel rises and sequentially reaches multiple temperatures, an initial gamma curve is adjusted based on the multiple decrease rates of the display panel at multiple grayscale values ​​to generate multiple adjusted gamma curves corresponding to those temperatures. The adjusted gamma curves corresponding to those temperatures are then transformed into multiple gamma-to-temperature functions corresponding to those grayscale values ​​to generate a gamma correction list. The method for forming these gamma-to-temperature functions includes: selecting multiple reference points from the adjusted gamma curves corresponding to those temperatures; performing coordinate axis transformation on these reference points to convert the grayscale axis to a temperature axis, generating multiple transformed reference points; and fitting these transformed reference points. Receive temperature data from the display panel; Retrieve the gamma correction list; Substitute the temperature data into the gamma pair temperature functions in the gamma correction list to generate multiple gamma adjustment points; A gamma correction curve is generated based on these gamma adjustment points; as well as The display panel displays an image based on the gamma correction curve.

2. The brightness correction method as described in claim 1, further comprising: Determine whether the temperature data is higher than a threshold, where: If the temperature data is lower than the threshold, control the display panel to operate according to an original gamma curve; and If the temperature data is higher than the threshold, the display panel is controlled to operate according to the gamma correction curve.

3. A display system, comprising: A display panel, wherein during a data setup phase, as the temperature of the display panel increases and sequentially reaches multiple temperatures, an initial gamma curve is adjusted based on multiple decrease rates of the display panel at multiple grayscale values ​​to generate multiple adjusted gamma curves corresponding to the temperatures; and the adjusted gamma curves corresponding to the temperatures are converted to multiple gamma-to-temperature functions corresponding to the grayscale values ​​to generate a gamma correction list, wherein the method for forming the gamma-to-temperature functions includes: selecting multiple reference points from the adjusted gamma curves respectively corresponding to the temperatures; performing coordinate axis transformation on the reference points to convert the grayscale axis to a temperature axis and generating multiple transformed reference points; and fitting the transformed reference points. A temperature sensor for sensing temperature data of the display panel; and A processing circuit, electrically coupled to the display panel and the temperature sensor, wherein the processing circuit is used to: Substitute the temperature data into the gamma pair temperature functions in the gamma correction list to generate multiple gamma adjustment points; and The gamma adjustment points are output to the display panel, wherein the display panel generates a gamma correction curve based on the gamma adjustment points to display a screen according to the gamma correction curve.

4. A brightness correction method, comprising: In a data establishment phase, multiple brightness values ​​of the display panel at multiple temperatures are received. Based on these brightness values ​​and multiple standard brightness values, multiple brightness reduction ratios of the display panel at these temperatures are calculated. Based on these brightness reduction ratios, multiple standard time intervals are adjusted to generate multiple adjusted time intervals. A lookup table is formed based on these temperatures and these adjusted time intervals. Receive temperature data from the display panel; Based on the lookup table, the temperature data is mapped to the adjusted time intervals corresponding to multiple sub-pixels; Based on these adjusted time intervals, the multiple light emission cycles of the sub-pixels of the display panel are corrected to generate multiple corrected light emission cycles; and The display panel displays an image based on the corrected emission cycles of the sub-pixels.

5. The brightness correction method as described in claim 4 further includes mapping the temperature data to the adjusted time intervals using a lookup table, wherein the adjusted time intervals corresponding to the sub-pixels are respectively greater than a plurality of standard time intervals for the sub-pixels.

6. The brightness correction method as described in claim 4, wherein the sub-pixels include a red sub-pixel, a green sub-pixel, and a blue sub-pixel.

Images