Timing controller, display device and driving method thereof
By adjusting the number and width of the light emission control start signal pulses through a gradual transition method, the problems of brightness jumps and nonlinearity in traditional display devices are solved, thereby improving display quality and increasing production efficiency.
Patent Information
- Application Number
- CN202511938524.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-19
- Publication Date
- 2026-02-24
AI Technical Summary
Traditional display devices are prone to brightness jumps and flickering when the number of pulses in the light emission control start signal changes, and the non-linear relationship in the PWM dimming method causes abnormal fluctuations in the brightness curve.
The number and width of the light emission control start signal are adjusted by a gradual transition method. By adding new pulses and gradually adjusting their width when the number of pulses changes, a mapping relationship between the digital brightness value and the total pulse width is established to correct the nonlinear relationship.
It effectively avoids brightness jumps and flickering, improves display quality, and reduces production debugging time and process complexity.
Smart Images
Figure CN121565091A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of display technology, specifically to a timing controller, a display device, and a driving method thereof. Background Technology
[0002] Currently, small and medium-sized active matrix organic light-emitting diode (AMOLED) display devices typically employ a hybrid dimming method to adjust different brightness ranges. This means that direct current (DC) dimming is used in high brightness areas, while pulse width modulation (PWM) dimming is used in low brightness areas.
[0003] DC dimming controls brightness by adjusting the intensity of the drive current, and its display non-uniformity is mainly manifested in its sensitivity to current changes. PWM dimming adjusts brightness by controlling the pulse width or number of pulses in the light emission control start signal, and its display non-uniformity is mainly manifested in its sensitivity to timing changes. Because these two dimming methods have different driving mechanisms, when the display device switches between the two dimming methods based on a digital brightness value, or when the number of pulses in the light emission control start signal is changed within the PWM dimming method, brightness jumps or flickering can easily occur at the switching points, affecting display quality.
[0004] To suppress brightness jumps at switching nodes, existing technologies typically use different gamma correction curves on either side of the switching node for compensation. This approach requires additional correction curve setting and debugging for each switching node, increasing debugging time and process complexity during production.
[0005] Furthermore, in PWM dimming, there is a non-linear relationship between the duty cycle change of the light emission control start signal and the actual brightness change. This non-linear relationship is caused by the coupling effect of the light emission control start signal on the anode of the organic light-emitting diode. This means that in low-brightness areas, even if the duty cycle of the light emission control start signal changes linearly, the actual brightness change will deviate from the expected linear relationship, resulting in abnormal fluctuations on the brightness curve, such as... Figure 1 As shown.
[0006] Therefore, it is necessary to propose a new technical solution to solve the above-mentioned technical problems. Summary of the Invention
[0007] The purpose of this application is to provide a timing controller, a display device, and a driving method thereof, which aims to solve the problem of brightness jump when the number of pulses of the light emission control start signal changes in traditional display devices.
[0008] This application provides a timing controller, comprising: a receiving unit configured to receive a digital brightness value; and a light emission control start signal generation unit configured to generate a light emission control start signal based on the digital brightness value, the light emission control start signal comprising a plurality of pulses; wherein the light emission control start signal generation unit is further configured to adjust the number of pulses of the light emission control start signal from a first number of pulses to a second number of pulses when the digital brightness value changes from a first value to a second number of pulses, the second number of pulses being greater than the first number of pulses; The light emission control start signal generation unit is also configured to adjust the width of the pulse after adjusting the number of pulses.
[0009] In the aforementioned timing controller, the light emission control start signal generation unit is further configured to add new pulses based on the first number of pulses, wherein the initial width of the new pulses is less than the width of the pulses corresponding to the first number of pulses.
[0010] In the aforementioned timing controller, the duration corresponding to the initial width of the new pulse is greater than or equal to the scan duration of one row of pixels in the driving cycle of one frame.
[0011] In the aforementioned timing controller, when the number of newly added pulses is increased in the light emission control start signal generation unit, the width of the pulse corresponding to the first number of pulses remains unchanged.
[0012] In the aforementioned timing controller, the light emission control start signal generation unit is further configured to increase the width of the newly added pulse until the width of the newly added pulse is equal to the width of the pulse corresponding to the first number of pulses.
[0013] In the aforementioned timing controller, when the width of the newly added pulse is increased in the light emission control start signal generation unit, the width of the pulse corresponding to the first number of pulses remains unchanged.
[0014] In the aforementioned timing controller, the light emission control start signal generation unit is further configured to synchronously increase the width of all pulses after the width of the newly added pulse is equal to the width of the pulse corresponding to the first number of pulses, until the target width is reached.
[0015] In the aforementioned timing controller, the timing controller further includes: a mapping relationship storage unit configured to store the mapping relationship between the digital brightness value and the total width of the pulses of the light emission control start signal; and a light emission control start signal generation unit configured to obtain the target total width of the pulses of the light emission control start signal according to the mapping relationship and the current digital brightness value, and to adjust the number and width of each pulse of the light emission control start signal according to the target total width, such that the sum of the widths of all pulses of the light emission control start signal is equal to the target total width.
[0016] This application also provides a display device, which includes a display panel and the aforementioned timing controller.
[0017] This application also provides a driving method for a display device, the driving method comprising: receiving a digital brightness value; and generating a light emission control start signal based on the digital brightness value, the light emission control start signal comprising a plurality of pulses; wherein, generating the light emission control start signal based on the digital brightness value comprises: adjusting the number of pulses of the light emission control start signal from a first number of pulses to a second number of pulses when the digital brightness value changes from a first value to a second number of pulses, the second number of pulses being greater than the first number of pulses; and adjusting the width of the pulses after adjusting the number of pulses.
[0018] In the above driving method, generating the light emission control start signal based on the digital brightness value further includes: adding a new pulse based on the first number of pulses, wherein the initial width of the new pulse is less than the width of the pulse corresponding to the first number of pulses.
[0019] In the above driving method, the duration corresponding to the initial width of the newly added pulse is greater than or equal to the scan duration of one row of pixels in the driving cycle of displaying one frame.
[0020] In the above driving method, when increasing the number of new pulses, the width of the pulse corresponding to the first number of pulses remains unchanged.
[0021] In the above driving method, generating the light emission control start signal based on the digital brightness value further includes: increasing the width of the new pulse until the width of the new pulse is equal to the width of the pulse corresponding to the first number of pulses.
[0022] In the above driving method, when increasing the width of the newly added pulse, the width of the pulse corresponding to the first number of pulses remains unchanged.
[0023] In the above driving method, generating the light emission control start signal based on the digital brightness value further includes: after the width of the newly added pulse is equal to the width of the pulse corresponding to the first number of pulses, synchronously increasing the width of all pulses until the target width is reached.
[0024] In the above driving method, generating the light emission control start signal based on the digital brightness value further includes: obtaining a pre-stored mapping relationship between the digital brightness value and the total width of the pulses of the light emission control start signal; obtaining a target total width of the pulses of the light emission control start signal based on the mapping relationship and the current digital brightness value; and adjusting the number and width of each pulse of the light emission control start signal based on the target total width, such that the sum of the widths of all pulses of the light emission control start signal is equal to the target total width.
[0025] The timing controller, display device, and driving method provided in the embodiments of this application solve the problem of brightness jump when the number of pulses changes in traditional display devices by using a gradual transition method to adjust the number and width of pulses during the process of adjusting the number of pulses of the light emission control start signal from the first number of pulses to the second number of pulses.
[0026] Specifically, when the digital brightness value changes from a first value to a second value, the light emission control start signal generation unit first adjusts the number of pulses in the light emission control start signal from the first number of pulses to the second number of pulses, and then adjusts the pulse width. During the pulse number adjustment process, the light emission control start signal generation unit adds new pulses based on the first number of pulses. The initial width of the new pulses is less than the width of the pulses corresponding to the first number of pulses, and the duration corresponding to the initial width of the new pulses is greater than or equal to the scan duration of one row of pixels in the drive cycle of displaying one frame. While increasing the number of new pulses, the width of the pulses corresponding to the first number of pulses remains unchanged, thus avoiding a sudden change in the total width of the light emission control start signal pulses caused by altering the width of the original pulses while increasing the number of pulses. Subsequently, the light emission control start signal generation unit increases the width of the new pulses until the width of the new pulses is equal to the width of the pulses corresponding to the first number of pulses. While increasing the width of the new pulses, the width of the pulses corresponding to the first number of pulses remains unchanged, thus achieving equalization of the width of all pulses. After the width of the newly added pulse becomes equal to the width of the pulse corresponding to the number of first pulses, the light emission control start signal generation unit synchronously increases the width of all pulses until the target width is reached. This achieves a smooth transition in the total width of the light emission control start signal pulses. Through the above three-stage gradual transition method, the total width of the light emission control start signal pulses is gradually adjusted as the digital brightness value changes, avoiding abrupt changes in the total width of the light emission control start signal pulses, thereby avoiding brightness jumps or flickering phenomena and improving display quality.
[0027] Furthermore, embodiments of this application also correct the nonlinear relationship between the duty cycle change of the light emission control start signal and the actual brightness change by establishing a mapping relationship between the digital brightness value and the total width of the pulse of the light emission control start signal. The mapping relationship storage unit stores the mapping relationship between the digital brightness value and the total width of the pulse of the light emission control start signal. The light emission control start signal generation unit obtains the target total width of the pulse of the light emission control start signal based on the mapping relationship and the current digital brightness value. Based on the target total width, it adjusts the number and width of each pulse of the light emission control start signal so that the sum of the widths of all pulses of the light emission control start signal equals the target total width. This mapping relationship is obtained by measuring the change curves of the digital brightness value and the actual brightness when the total width of the pulse of the light emission control start signal changes in equal steps, and then performing linear interpolation using the target brightness. This mapping relationship compensates for the nonlinear effect caused by the coupling effect of the light emission control start signal on the anode of the organic light-emitting diode. Through this mapping relationship, the light emission control start signal generation unit calculates the target total width of the pulse of the light emission control start signal based on the change of the digital brightness value, thereby ensuring that the actual brightness changes linearly with the digital brightness value and avoiding abnormal fluctuations in the brightness curve in low-brightness areas.
[0028] The embodiments of this application use a gradual transition method to eliminate brightness jumps when the number of pulses changes. It does not require setting an additional gamma correction curve for compensation at the node where the number of pulses changes, thereby reducing debugging time and process complexity in the production process and lowering production costs. Attached Figure Description
[0029] Figure 1 This is a schematic diagram illustrating the phenomenon where the actual brightness change deviates from the expected linear relationship in traditional technical solutions.
[0030] Figure 2 This is a schematic diagram of a display device provided in an embodiment of this application.
[0031] Figure 3 This is a schematic diagram illustrating a technical solution for adjusting the number and width of pulses using a gradual transition method, as provided in an embodiment of this application. Detailed Implementation
[0032] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.
[0033] The terms “first,” “second,” and similar words do not indicate any order, quantity, or importance, but are merely used to distinguish different technical features. The terms “multiple,” and similar words mean two or more, unless otherwise expressly specified.
[0034] The technical solutions of different embodiments of this application can be combined with each other.
[0035] Embodiments of this application provide a timing controller, a display device, and a driving method thereof. The display device is one of an active-matrix organic light-emitting diode (OLED) display device, a miniature OLED display device, or a micro-OLED display device. The following description assumes the display device is an active-matrix organic light-emitting diode (OLED) display device.
[0036] like Figure 2 As shown, the display device includes a display panel (DP), a timing controller, and a source driver chip.
[0037] The display panel (DP) includes at least one gate driving circuit, multiple pixel units (PX), multiple first power lines (VDD), multiple second power lines (VSS), multiple gate lines (SCAN), multiple light emission control signal lines (EM), and multiple data lines (DATA). The pixel units (PX) are arranged in an array. Each pixel unit (PX) includes an organic light-emitting diode (OLED) and a driving circuit. The driving circuit is electrically connected to the first power line (VDD), the second power line (VSS), the gate line (SCAN), the light emission control signal line (EM), and the data line (DATA). The driving circuit provides a driving current to the OLED according to the data signal transmitted on the data line (DATA), and the OLED emits light according to the driving current. The light emission control signal line (EM) is used to transmit light emission control signals, which are used to control the light emission timing of the OLED.
[0038] The timing controller is electrically connected to the source driver chip and the gate driver circuit. The timing controller receives externally input image data and control signals, transmits the processed image data to the source driver chip, and transmits timing control signals to the gate driver circuit.
[0039] The gate drive circuit is electrically connected to multiple gate lines SCAN. The gate drive circuit is used to provide scan signals to the gate lines SCAN to scan the pixel unit PX line by line.
[0040] The source driver chip is electrically connected to multiple data lines DATA. The source driver chip is used to convert image data into data signals, and transmit the data signals to the pixel unit PX through the data lines DATA.
[0041] The timing controller of the display device includes a receiving unit, a light emission control start signal generation unit, and a mapping relationship storage unit.
[0042] The receiving unit is used to receive digital brightness values. The digital brightness value represents the target brightness level of the display device.
[0043] The luminance control start signal generation unit is electrically connected to the receiving unit and the display panel DP. The luminance control start signal generation unit generates a luminance control start signal EMSTV based on the digital brightness value and outputs the luminance control start signal EMSTV to the display panel DP. The display panel DP includes a shift register, which is electrically connected to the luminance control start signal generation unit. The shift register receives the luminance control start signal EMSTV and generates multiple luminance control signals based on it. The shift register outputs these multiple luminance control signals to the multi-row pixel unit PX through the luminance control signal line EM. The luminance control start signal EMSTV is a pulse signal, consisting of multiple pulses. Each pulse has a high-level time and a low-level time. The high-level time corresponds to the luminance time of the organic light-emitting diode (OLED), and the low-level time corresponds to the non-luminance time of the OLED.
[0044] The mapping relationship storage unit is electrically connected to the light emission control start signal generation unit. The mapping relationship storage unit is used to store the mapping relationship between the digital brightness value and the total pulse width of the light emission control start signal EMSTV. The total pulse width of the light emission control start signal EMSTV is the sum of the widths of all pulses of the light emission control start signal EMSTV, and the pulse width corresponds to the high-level time of the pulse.
[0045] The display device employs a hybrid dimming method to adjust brightness across different ranges. In the high-brightness area, the device uses DC dimming, controlling the brightness of the organic light-emitting diode (OLED) by adjusting the intensity of the drive current. In the low-brightness area, the device uses pulse-width modulation (PWM) dimming, adjusting the number or width of the pulses in the emission control start signal (EMSTV) to regulate the brightness of the OLED.
[0046] In pulse width modulation (PWM) dimming, when the digital brightness value changes from a first value to a second value, the number of pulses in the luminance control start signal (EM STV) needs to be adjusted from the first pulse count to the second pulse count. The first value is greater than the second value, and the first pulse count is less than the second pulse count. To avoid brightness jumps or flickering when the number of pulses changes, the luminance control start signal generation unit uses a gradual transition method to adjust the pulse count and pulse width of the luminance control start signal (EM STV).
[0047] like Figure 3 As shown, the gradual transition method includes three stages.
[0048] The first stage is the creation stage of new pulses. In this stage, the light emission control start signal generation unit adds new pulses based on the first number of pulses. The number of new pulses gradually increases from zero to a target number, which is equal to the difference between the second number of pulses and the first number of pulses. The initial width of the new pulse is less than the width of the pulse corresponding to the first number of pulses. The duration corresponding to the initial width of the new pulse is greater than or equal to the scan duration of one row of pixels in the driving cycle of displaying one frame. The scan duration of one row of pixels is defined as one pixel row scan cycle. When increasing the number of new pulses, the width of the pulse corresponding to the first number of pulses remains unchanged, and the width of the new pulse remains the initial width.
[0049] Specifically, the light emission control start signal generation unit gradually increases the number of new pulses based on changes in the digital brightness value. When the digital brightness value decreases from a first value to a first intermediate value, the number of new pulses increases from zero to the target number. During this process, the total number of pulses in the light emission control start signal EM STV increases from a first number of pulses to a second number of pulses, and the total width of the pulses in the light emission control start signal EM STV increases from a first total width to a first intermediate total width. The first total width is equal to the product of the first number of pulses and the width of the pulses corresponding to the first number of pulses, and the first intermediate total width is equal to the sum of the first total width and the products of the target number and the initial width of the new pulses.
[0050] The second stage is the width equalization stage for the newly added pulses. In this stage, the light emission control start signal generation unit increases the width of the newly added pulses until the width of the newly added pulses is equal to the width of the pulses corresponding to the first number of pulses. While increasing the width of the newly added pulses, the width of the pulses corresponding to the first number of pulses remains unchanged, and the number of newly added pulses remains at the target number.
[0051] Specifically, the light emission control start signal generation unit gradually increases the width of the newly added pulses according to the change in the digital brightness value. When the digital brightness value decreases from a first intermediate value to a second intermediate value, the width of the newly added pulse increases from the initial width to the width of the pulse corresponding to the first number of pulses. During this process, the total number of pulses in the light emission control start signal EMSTV remains at the second number of pulses, and the total width of the pulses in the light emission control start signal EMSTV increases from the first intermediate total width to the second intermediate total width. The second intermediate total width is equal to the product of the second number of pulses and the width of the pulse corresponding to the first number of pulses.
[0052] The third stage is the synchronous increase stage of the width of all pulses. In this stage, the light emission control start signal generation unit synchronously increases the width of all pulses until the width of all pulses reaches the target width. While increasing the width of all pulses, the width of all pulses remains equal, and the number of all pulses remains the same as the second pulse number.
[0053] Specifically, the luminance control start signal generation unit synchronously increases the width of all pulses according to the change in the digital brightness value. When the digital brightness value decreases from the second intermediate value to the second value, the width of all pulses increases from the width of the pulses corresponding to the first number of pulses to the target width. During this process, the total number of pulses of the luminance control start signal EMSTV remains at the second number of pulses, and the total width of the pulses of the luminance control start signal EMSTV increases from the second intermediate total width to the second total width. The second total width is equal to the product of the second number of pulses and the target width.
[0054] Through the gradual transition of the above three stages, the total width of the pulse of the light emission control start signal EMSTV gradually increases as the digital brightness value decreases. The change in the total width of the pulse of the light emission control start signal EMSTV is continuous, avoiding abrupt changes in the total width of the pulse of the light emission control start signal EMSTV, thereby avoiding brightness jumps or flickering phenomena.
[0055] In one specific embodiment, the display panel DP has a resolution of 1200 rows by 600 columns. The driving cycle for displaying one frame includes the driving time of the display phase and the driving time of the blanking phase. The driving time of the display phase is 1200 pixel row scan cycles, and the driving time of the blanking phase is 300 pixel row scan cycles. The total duration of the driving cycle for displaying one frame is 1500 pixel row scan cycles. The number of first pulses is 3, the number of second pulses is 15, the width of the pulse corresponding to the number of first pulses is 25 pixel row scan cycles, the initial width of the newly added pulse is 1 pixel row scan cycle, the target number is 12, and the target width is 40 pixel row scan cycles.
[0056] In the first stage, the emission control start signal generation unit gradually increases the number of new pulses from 0 to 12, based on the existing 3 pulses. The width of the new pulses remains one pixel line scan cycle, and the width of the existing 3 pulses remains 25 pixel line scan cycles. When the number of new pulses is 6, the total width of the emission control start signal EM STV is 81 pixel line scan cycles, and the duty cycle of the emission control start signal EM STV is 5.4%. When the number of new pulses is 12, the total width of the emission control start signal EM STV is 87 pixel line scan cycles.
[0057] In the second stage, the width of the emission control start signal generation unit is increased by 12 new pulses, from 1 pixel line scan cycle to 25 pixel line scan cycles, while the width of the 3 pulses remains at 25 pixel line scan cycles. When the width of the 12 new pulses reaches 25 pixel line scan cycles, the total pulse width of the emission control start signal EMSTV is 375 pixel line scan cycles.
[0058] In the third stage, the width of the emission control start signal generation unit is synchronously increased by 15 pulses, from 25 pixel line scan cycles to 40 pixel line scan cycles. When the width of the 15 pulses reaches 40 pixel line scan cycles, the total pulse width of the emission control start signal EMSTV is 600 pixel line scan cycles, and the duty cycle of the emission control start signal EMSTV is 40%.
[0059] In another embodiment, the first pulse number is 3, and the second pulse number is an integer between 15 and 32. By adjusting the second pulse number, the display device can achieve different brightness adjustment ranges and precisions in different application scenarios.
[0060] To correct the non-linear relationship between the duty cycle change of the luminance control start signal EMSTV and the actual brightness change, a mapping relationship storage unit stores the mapping relationship between the digital brightness value and the total pulse width of the luminance control start signal EMSTV. This mapping relationship is used to correct the non-linear brightness change caused by the coupling effect of the luminance control start signal EMSTV on the anode of the organic light-emitting diode of the display panel DP. This mapping relationship is established in the following way.
[0061] First, the relationship between the digital brightness value and the actual brightness is established when the total width of the luminance control start signal (EM STV) pulse changes in equal steps. The equal step size is the amount of change in the total width of the luminance control start signal (EM STV) pulse, and its unit is the pixel line scan cycle. During the measurement process, the total width of the luminance control start signal (EM STV) pulse changes gradually according to a preset step size, and the digital brightness value and actual brightness corresponding to the total width of each luminance control start signal (EM STV) pulse are recorded. The actual brightness is obtained by measuring with a brightness measurement device.
[0062] Then, based on the first relationship between the measured digital brightness value and the actual brightness, and the linear relationship between the digital brightness value and the target brightness, the mapping relationship between the digital brightness value and the total pulse width of the luminance control start signal (EM STV) is calculated through interpolation. The target brightness is the desired linear brightness value, which changes linearly with the digital brightness value. Using a linear interpolation method, the total pulse width of the luminance control start signal (EM STV) corresponding to the target brightness is calculated based on the correspondence between the measured digital brightness value and the actual brightness.
[0063] Finally, a mapping relationship is established between the digital brightness values and the total pulse width of the luminance control start signal (EM STV), and this mapping relationship is stored in the mapping relationship storage unit. This mapping relationship includes multiple digital brightness values and the corresponding total pulse width of the luminance control start signal (EM STV).
[0064] In one specific embodiment, the data shown in Table 1 are obtained when the total pulse width of the emission control start signal EMSTV is varied in equal steps.
[0065]
[0066] Table 1 Table 1 shows the non-linear relationship between the digital brightness value and the actual brightness when the total pulse width of the luminance control start signal EM STV changes in constant steps. As shown in Table 1, when the digital brightness value changes from 300 to 280, the total pulse width of the luminance control start signal EM STV increases from 75 pixel line scan cycles to 283 pixel line scan cycles, an increase of 208 pixel line scan cycles, but the actual brightness only decreases from 80 nits to 79.9 nits, a change of only 0.1 nits. Conversely, when the digital brightness value changes from 120 to 100, the total pulse width of the luminance control start signal EM STV increases from 579 pixel line scan cycles to 600 pixel line scan cycles, an increase of 21 pixel line scan cycles, but the actual brightness decreases from 65.04 nits to 60 nits, a change of only 5.04 nits. This indicates that the coupling effect of the light emission control start signal EMSTV on the anode of the organic light-emitting diode leads to a nonlinear change in brightness. In the low brightness region, the same change in total pulse width corresponds to a larger change in brightness, while in the high brightness region, the same change in total pulse width corresponds to a smaller change in brightness.
[0067] To achieve a linear change in brightness with the digital brightness value, it is necessary to establish a mapping relationship between the digital brightness value and the total pulse width of the luminance control start signal (EM STV). Based on the linear relationship between the digital brightness value and the target brightness, the total pulse width of the luminance control start signal (EM STV) corresponding to the target brightness is calculated using a linear interpolation method, according to the correspondence between the brightness measured by equal steps and the digital brightness value in Table 1. The mapping relationship shown in Table 2 is obtained.
[0068]
[0069] Table 2 Table 2 shows the mapping relationship between the digital brightness value and the total pulse width of the corrected luminance control start signal (EM STV). The target brightness is the desired linear brightness value, which changes linearly with the digital brightness value. Using linear interpolation, based on the correspondence between the measured brightness and the digital brightness value in Table 1 (equal step increments), the total pulse width of the luminance control start signal (EM STV) corresponding to the target brightness is calculated. For example, when the digital brightness value is 280, the target brightness is 78 nits. Linear interpolation calculates the total pulse width of the luminance control start signal (EM STV) corresponding to the target brightness to be 128 pixel line scan cycles. Table 2 shows that when the digital brightness value changes from 300 to 280, the total pulse width of the corrected luminance control start signal (EM STV) increases from 75 pixel line scan cycles to 128 pixel line scan cycles, an increase of 53 pixel line scan cycles. The target brightness decreases from 80 nits to 78 nits, a change of 2 nits. When the digital brightness value changes from 140 to 120, the total pulse width of the corrected luminance control start signal EMSTV increases from 495 pixel line scan cycles to 548 pixel line scan cycles, an increase of 53 pixel line scan cycles. The target brightness decreases from 64 nits to 62 nits, a change of 2 nits. Through this mapping relationship, the luminance control start signal generation unit calculates the target total pulse width of the luminance control start signal EMSTV based on the change in the digital brightness value, thus ensuring that the actual brightness changes linearly with the digital brightness value.
[0070] The luminance control start signal generation unit obtains the target total width of the pulses of the luminance control start signal EM STV based on the mapping relationship and the current digital brightness value. Based on the target total width, the luminance control start signal generation unit adjusts the number and width of each pulse of the luminance control start signal EM STV so that the sum of the widths of all pulses of the luminance control start signal EM STV equals the target total width.
[0071] The display device and driving method provided in the embodiments of this application solve the problem of brightness jump when the number of pulses changes in traditional display devices by using a gradual transition method to adjust the number and width of pulses during the process of adjusting the number of pulses of the light emission control start signal EMSTV from the first number of pulses to the second number of pulses.
[0072] Specifically, when the digital brightness value changes from a first value to a second value, the luminance control start signal generation unit first adjusts the number of pulses in the luminance control start signal EMSTV from the first number of pulses to the second number of pulses, and then adjusts the pulse width. During the pulse number adjustment process, the luminance control start signal generation unit adds new pulses based on the first number of pulses. The initial width of the new pulses is less than the width of the pulses corresponding to the first number of pulses, and the duration corresponding to the initial width of the new pulses is greater than or equal to the scan duration of one row of pixels in the drive cycle of displaying one frame. While increasing the number of new pulses, the width of the pulses corresponding to the first number of pulses remains unchanged, thus avoiding a sudden change in the total pulse width of the luminance control start signal EMSTV caused by altering the width of the original pulses while increasing the pulse number. Subsequently, the luminance control start signal generation unit increases the width of the new pulses until the width of the new pulses is equal to the width of the pulses corresponding to the first number of pulses. While increasing the width of the new pulses, the width of the pulses corresponding to the first number of pulses remains unchanged, thus achieving equalization of the width of all pulses. After the width of the newly added pulse becomes equal to the width of the pulse corresponding to the number of first pulses, the emission control start signal generation unit synchronously increases the width of all pulses until the target width is reached. This achieves a smooth transition in the total width of the emission control start signal EM STV pulses. Through the above three-stage gradual transition method, the total width of the emission control start signal EM STV pulses is gradually adjusted as the digital brightness value changes, avoiding abrupt changes in the total width of the emission control start signal EM STV pulses, thereby avoiding brightness jumps or flickering phenomena and improving display quality.
[0073] Furthermore, embodiments of this application also correct the nonlinear relationship between the duty cycle change of the luminance control start signal (EM STV) and the actual brightness change by establishing a mapping relationship between the digital brightness value and the total pulse width of the luminance control start signal (EM STV). The mapping relationship storage unit stores the mapping relationship between the digital brightness value and the total pulse width of the luminance control start signal (EM STV). The luminance control start signal generation unit obtains the target total pulse width of the luminance control start signal (EM STV) based on the mapping relationship and the current digital brightness value. Based on the target total width, it adjusts the number and width of each pulse of the luminance control start signal (EM STV) so that the sum of the widths of all pulses of the luminance control start signal (EM STV) equals the target total width. This mapping relationship is obtained by measuring the change curves of the digital brightness value and the actual brightness when the total pulse width of the luminance control start signal (EM STV) changes in equal steps, and then performing linear interpolation using the target brightness. This mapping relationship compensates for the nonlinear effect caused by the coupling effect of the luminance control start signal (EM STV) on the anode of the organic light-emitting diode. Through this mapping relationship, the luminance control start signal generation unit calculates the target total pulse width of the luminance control start signal EMSTV based on the change in digital brightness value, thereby ensuring that the actual brightness changes linearly with the digital brightness value and avoiding abnormal fluctuations in the brightness curve in the low brightness area.
[0074] The embodiments of this application use a gradual transition method to eliminate brightness jumps when the number of pulses changes. It does not require setting an additional gamma correction curve for compensation at the node where the number of pulses changes, thereby reducing debugging time and process complexity in the production process and lowering production costs.
[0075] Embodiments of this application also provide a driving method for a display device, which is applied to the aforementioned display device. The driving method includes the following steps.
[0076] Step S1: Receive digital brightness value.
[0077] Step S2: Obtain the mapping relationship between the pre-stored digital brightness value and the total pulse width of the light emission control start signal EMSTV.
[0078] Step S3: Determine the target total width of the pulse of the luminance control start signal EMSTV based on the mapping relationship and the current digital brightness value.
[0079] Step S4: Determine whether the current digital brightness value requires changing the number of pulses in the EMSTV (Emission Control Start Signal). If the current digital brightness value requires changing the number of pulses in the EMSTV, proceed to step S5. If the current digital brightness value does not require changing the number of pulses in the EMSTV, proceed to step S9.
[0080] Step S5: Add new pulses based on the first number of pulses. The number of new pulses gradually increases from zero to the target number. The width of the new pulses remains the initial width, and the width of the pulses corresponding to the first number of pulses remains unchanged. The duration corresponding to the initial width of the new pulses is greater than or equal to the scan duration of one row of pixels in the driving cycle of displaying one frame.
[0081] Step S6: Increase the width of the new pulse until the width of the new pulse is equal to the width of the pulse corresponding to the first number of pulses, while the width of the pulse corresponding to the first number of pulses remains unchanged.
[0082] Step S7: After the width of the newly added pulse is equal to the width of the pulse corresponding to the number of first pulses, the width of all pulses is increased synchronously until the width of all pulses reaches the target width.
[0083] Step S8: Generate the light emission control start signal EMSTV based on the number of pulses and pulse width of the adjusted light emission control start signal EMSTV.
[0084] Step S9: Directly adjust the pulse width of the light emission control start signal EMSTV so that the sum of the widths of all pulses of the light emission control start signal EMSTV equals the target total width.
[0085] Step S10: Output the light emission control start signal EM STV to the display panel DP. The shift register of the display panel DP receives the light emission control start signal EM STV and generates multiple light emission control signals according to the light emission control start signal EM STV. The shift register outputs the multiple light emission control signals to the multi-row pixel unit PX through the light emission control signal line EM.
[0086] In this driving method, the mapping relationship is established as follows: A first relationship between the digital brightness value and the actual brightness is measured when the total width of the pulse of the emission control start signal EM STV changes in equal steps. The unit of equal steps is the scan duration of one row of pixels in one frame of the display. Based on the linear relationship between the digital brightness value and the target brightness, the mapping relationship between the digital brightness value and the total width of the pulse of the emission control start signal EM STV is calculated through interpolation. The mapping relationship corrects for the non-linear brightness change caused by the coupling effect of the emission control start signal EM STV on the anode of the organic light-emitting diode of the display panel DP.
[0087] The display device and driving method provided in the embodiments of this application are applicable to display devices that require pulse width modulation (PWM) dimming, such as active matrix organic light-emitting diode (OLED) display devices, mini OLED display devices, and micro OLED display devices. The display device and driving method are implemented in a display driver chip, a timing controller, or an application processor.
[0088] The embodiments of this application have been described in detail above. The content of this specification should not be construed as limiting the scope of protection of this application.
Claims
1. A timing controller, characterized in that, The timing controller includes: The receiving unit is configured to receive digital brightness values; and A light emission control start signal generation unit is configured to generate a light emission control start signal based on the digital brightness value, the light emission control start signal comprising multiple pulses; The light emission control start signal generation unit is further configured to adjust the number of pulses of the light emission control start signal from the first number of pulses to the second number of pulses when the digital brightness value changes from the first value to the second value, wherein the second number of pulses is greater than the first number of pulses. The light emission control start signal generation unit is also configured to adjust the width of the pulse after adjusting the number of pulses.
2. The timing controller according to claim 1, characterized in that, The light emission control start signal generation unit is further configured to add new pulses based on the first number of pulses, wherein the initial width of the new pulses is less than the width of the pulses corresponding to the first number of pulses.
3. The timing controller according to claim 2, characterized in that, The duration corresponding to the initial width of the newly added pulse is greater than or equal to the scan duration of one row of pixels in the driving cycle of one frame.
4. The timing controller according to claim 2, characterized in that, When the number of new pulses is increased in the light emission control start signal generation unit, the width of the pulse corresponding to the first number of pulses remains unchanged.
5. The timing controller according to claim 2, characterized in that, The light emission control start signal generation unit is further configured to increase the width of the newly added pulse until the width of the newly added pulse is equal to the width of the pulse corresponding to the first number of pulses.
6. The timing controller according to claim 5, characterized in that, When the width of the newly added pulse is increased in the light emission control start signal generation unit, the width of the pulse corresponding to the first number of pulses remains unchanged.
7. The timing controller according to claim 5, characterized in that, The light emission control start signal generation unit is further configured to synchronously increase the width of all pulses after the width of the newly added pulse is equal to the width of the pulse corresponding to the first number of pulses, until the target width is reached.
8. The timing controller according to claim 1, characterized in that, The timing controller further includes: The mapping relationship storage unit is configured to store the mapping relationship between the digital brightness value and the total width of the pulse of the light emission control start signal; The light emission control start signal generation unit is configured to obtain the target total width of the pulses of the light emission control start signal according to the mapping relationship and the current digital brightness value, and to adjust the number and width of each pulse of the light emission control start signal according to the target total width, such that the sum of the widths of all pulses of the light emission control start signal is equal to the target total width.
9. A display device, characterized in that, The display device includes a display panel and a timing controller as described in any one of claims 1 to 8.
10. A driving method for a display device, characterized in that, The driving method includes: Receive digital brightness values; and A light emission control start signal is generated based on the digital brightness value, and the light emission control start signal includes multiple pulses; The step of generating a light emission control start signal based on the digital brightness value includes: When the digital brightness value changes from a first value to a second value, the number of pulses in the light emission control start signal is adjusted from the first pulse number to the second pulse number, where the second pulse number is greater than the first pulse number; and After adjusting the number of pulses, adjust the width of the pulses.
11. The driving method according to claim 10, characterized in that, The step of generating the light emission control start signal based on the digital brightness value further includes: An additional pulse is added based on the first number of pulses, and the initial width of the additional pulse is less than the width of the pulse corresponding to the first number of pulses.
12. The driving method according to claim 11, characterized in that, The duration corresponding to the initial width of the newly added pulse is greater than or equal to the scan duration of one row of pixels in the driving cycle for displaying one frame.
13. The driving method according to claim 11, characterized in that, When increasing the number of new pulses, the width of the pulse corresponding to the first number of pulses remains unchanged.
14. The driving method according to claim 11, characterized in that, The step of generating the light emission control start signal based on the digital brightness value further includes: Increase the width of the newly added pulse until the width of the newly added pulse is equal to the width of the pulse corresponding to the first number of pulses.
15. The driving method according to claim 14, characterized in that, When increasing the width of the newly added pulse, the width of the pulse corresponding to the first number of pulses remains unchanged.
16. The driving method according to claim 14, characterized in that, The step of generating the light emission control start signal based on the digital brightness value further includes: After the width of the newly added pulse becomes equal to the width of the pulse corresponding to the first number of pulses, the width of all pulses is increased synchronously until the target width is reached.
17. The driving method according to claim 10, characterized in that, The step of generating the light emission control start signal based on the digital brightness value further includes: Obtain the mapping relationship between the pre-stored digital brightness value and the total pulse width of the light emission control start signal; Based on the mapping relationship and the current digital brightness value, the target total width of the pulse of the light emission control start signal is obtained; and Based on the target total width, adjust the number and width of each pulse of the light emission control start signal so that the sum of the widths of all pulses of the light emission control start signal equals the target total width.