Image display method, DDIC chip, display screen module and terminal

Abstract

Embodiments of the present application disclose an image display method, a DDIC chip, a display screen module and a terminal. The method is used for a DDIC chip of a display screen, and the method comprises: in a display process of a Kth frame of image, adjusting a light-emitting duty cycle of an EM cycle in a light-emitting scanning process based on a current display parameter, the light-emitting duty cycle refers to a ratio of a light-emitting time length in the EM cycle, the EM cycle comprises a light-emitting stage and an off stage, and K is a positive integer. The DDIC chip adjusts the light-emitting duty cycle of the EM cycle, compensates screen brightness, avoids flickering phenomenon caused by screen brightness change, and further improves image display quality of the display screen.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to an image display method, a display driver integrated circuit (DDIC) chip, a display module, and a terminal. Background Technology

[0002] Active-Matrix Organic Light-Emitting Diode (AMOLED) is a self-emissive display technology that is widely used in smartphones, tablets, wearable devices and other terminals.

[0003] During image display, the DDIC chip controls the LEDs in the display screen to switch on and off periodically, that is, to periodically control the LEDs to light up and turn off, so as to ensure that the display screen is in a continuously lit state. Summary of the Invention

[0004] This application provides an image display method, a DDIC chip, a display module, and a terminal. The technical solution is as follows:

[0005] On one hand, embodiments of this application provide an image display method, the method being used in a display driver circuit DDIC chip for a display screen, the method comprising:

[0006] During the display of the Kth frame image, the emission duty cycle of the EM cycle during the emission (EM) scanning process is adjusted based on the current display parameters. The emission duty cycle refers to the proportion of the emission duration within the EM cycle. The EM cycle includes an emission phase and a shutdown phase, and K is a positive integer.

[0007] On the other hand, embodiments of this application provide a DDIC chip, which is applied to a display screen and is used for:

[0008] During the display of the Kth frame image, the emission duty cycle of the EM cycle during the emission scanning process is adjusted based on the current display parameters. The emission duty cycle refers to the proportion of emission time within the EM cycle. The EM cycle includes an emission phase and an off phase, and K is a positive integer.

[0009] On the other hand, embodiments of this application provide a display module, which includes a display screen and a DDIC chip. The DDIC chip is used to drive the display screen and to implement the image display method as described above.

[0010] On the other hand, embodiments of this application provide a terminal, which includes an application processor (AP), a display screen and a DDIC chip. The AP and the DDIC chip are connected via a Mobile Industry Processor Interface (MIPI), and the DDIC chip is used to implement the image display method as described above.

[0011] In this embodiment, the DDIC chip adjusts the light emission duty cycle of the EM cycle during EM scanning to adjust the light emission duration within the EM cycle. This compensates for screen brightness changes caused by leakage current, improves the stability of screen brightness during image display, avoids flickering caused by screen brightness changes, and helps improve the image display quality of the display screen. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram illustrating the relationship between screen brightness and time at different refresh rates in related technologies;

[0014] Figure 2 This is a flowchart of an image display method provided in an exemplary embodiment of this application;

[0015] Figure 3 This is a schematic diagram illustrating the use of PWM technology to adjust the duty cycle of EM periodic emission;

[0016] Figure 4 This is a schematic diagram illustrating the relationship between screen brightness and time after adjusting the EM periodic emission duty cycle, provided in an exemplary embodiment of this application.

[0017] Figure 5 This is a schematic diagram illustrating the relationship between screen brightness and time before adjusting the EM periodic emission duty cycle, provided in an exemplary embodiment of this application.

[0018] Figure 6 This is a schematic diagram illustrating the relationship between screen brightness and time after adjusting the EM periodic emission duty cycle, provided in an exemplary embodiment of this application.

[0019] Figure 7The brightness change curve is a schematic diagram illustrating the relationship between screen brightness and time before EM cycle duty cycle adjustment, under the condition that the correlation between brightness and EM cycle is irregular.

[0020] Figure 8 This is a schematic diagram illustrating the relationship between screen brightness and time after adjusting the EM cycle duty cycle, where the brightness variation curve represents an irregular correlation between brightness and EM cycle.

[0021] Figure 9 This is a flowchart of an image display method provided in another exemplary embodiment of this application;

[0022] Figure 10 This is a schematic diagram showing the relationship between screen brightness and time when the emission duty cycle of a specified EM cycle is adjusted during EM scanning.

[0023] Figure 11 This is a structural block diagram of a terminal provided in an exemplary embodiment of this application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0025] Refresh rate: The number of times a display refreshes its image per second, measured in Hz. The smoothness of the display is related to the refresh rate; a higher refresh rate results in smoother visuals. In some embodiments, the display refresh rate varies depending on the scenario to meet different display requirements. For example, in static text reading scenarios, where the text doesn't change frequently in a short time, the refresh rate is set to 10Hz; in video playback scenarios, where video frame rates are typically below 60Hz, the refresh rate is set to 60Hz; and in gaming scenarios, where the game visuals change rapidly and smoothness is crucial, the refresh rate is set to 120Hz.

[0026] Emission (EM) Cycle: The EM signal is a panel row switching signal used to control whether the pixels in the current row emit light. The switching cycle of the switching signal is called the EM cycle. Each EM cycle is divided into two phases: Emission ON and Emission OFF. The proportion of the emission duration (i.e., the duration of the emission phase) within an EM cycle is called the emission duty cycle.

[0027] EM Frequency: The EM frequency is the frequency at which the EM signal is generated. Typically, the EM frequency is an integer multiple of the refresh rate, meaning that the EM is switched on and off multiple times between two image refreshes. The ratio of the EM refresh rate to the refresh rate is the number of EM pulses (EM-pulse-no) corresponding to a single image refresh. For example, when the refresh rate is 60Hz, an EM frequency of 240Hz or 360Hz corresponds to EM-pulse-nos of 4 and 6, respectively.

[0028] In operation, the DDIC chip controls image refresh while simultaneously emitting an EM signal to control the display screen to emit light, enabling the screen to display the corresponding image. To ensure screen brightness, the DDIC chip needs to control the display screen to emit light multiple times between adjacent image refreshes.

[0029] However, due to differences in display materials and calibration methods, different displays have different display characteristics, and consequently, their performance in maintaining brightness varies considerably.

[0030] For example, if LTPS (Low Temperature Poly-silicon) material is used as the substrate material of the display, the substrate leakage current is large due to the high mobility of the active layer of LTPS. This results in a severe decrease in screen brightness after one image scan is completed. During the next image scan, the screen brightness increases instantaneously because voltage is re-provided to the current row pixel circuit, ultimately causing screen flickering.

[0031] Taking an LTPS display with an EM frequency of 360Hz as an example, such as Figure 1 As shown, it illustrates the relationship between screen brightness and time at different refresh rates, where the horizontal axis represents time and the vertical axis represents screen brightness.

[0032] Figure 1 The values ​​labeled on the left refer to the refresh rate. Since the EM frequency is often an integer multiple of the refresh rate, there are multiple EM cycles between two adjacent image refreshes. For example... Figure 1 As shown, when the refresh rate is 90Hz, the EM frequency is 360Hz, so there should be 4 EM cycles between two consecutive image refreshes. Similarly, when the refresh rate is 40Hz, there are 9 EM cycles between two consecutive image refreshes.

[0033] from Figure 1 As can be seen, due to severe leakage current in LTPS displays, the screen brightness gradually decreases over time after each image refresh. When the next image refresh occurs, the sudden increase in screen brightness causes a visual flickering effect, affecting the user experience. Furthermore, the greater the jump in screen brightness as the refresh rate decreases, the more noticeable the flickering becomes.

[0034] To alleviate screen flickering, this embodiment adjusts the light emission duty cycle of the EM cycle during EM scanning using a DDIC chip, compensating for screen brightness changes caused by leakage current, and avoiding sudden changes in screen brightness during image refresh, thereby mitigating screen flickering and improving the image display quality of the display screen.

[0035] Figure 2 This is a flowchart of an exemplary embodiment of the image display method provided in this application. This embodiment uses the method applied to a DDIC chip as an example for illustration. The method includes:

[0036] Step 201: During the display of the Kth frame image, adjust the emission duty cycle of the EM cycle during the EM scan based on the current display parameters. The emission duty cycle refers to the proportion of emission time within the EM cycle. The EM cycle includes an emission phase and an off phase, and K is a positive integer.

[0037] In some embodiments, the image frame data of the Kth frame may be a new image frame data transmitted by the AP, or the image frame data may be a historical image frame data cached by the DDIC chip (i.e., the DDIC chip will repeatedly refresh based on the historical image frame data if it does not receive new image frame data).

[0038] In some embodiments, during the complete display of the Kth frame image (including image scanning), the DDIC chip adjusts the emission duty cycle of the EM cycle during EM scanning based on the current display parameters.

[0039] In other embodiments, during image scanning based on the image frame data of the Kth frame, the DDIC chip performs EM scanning according to an initial emission duty cycle. Upon completion of the image scanning, the DDIC chip adjusts the emission duty cycle of the EM period during the EM scanning process based on the current display parameters. In this case, before scanning the (K+1)th frame, the DDIC chip adjusts the emission duty cycle of the EM period to its initial value, thereby performing EM scanning based on the initial emission duty cycle during the (K+1)th frame image scanning process, and adjusting the emission duty cycle of the EM period during the EM scanning process upon completion of the (K+1)th frame image scanning.

[0040] In one possible implementation, the DDIC chip adjusts the light emission duty cycle of the EM cycle during the EM scan based on the characteristics of screen brightness changes during the EM scan.

[0041] The luminous duty cycle refers to the percentage of time the screen is illuminated within the EM cycle, which includes an illuminating phase and an off phase. The luminous duty cycle affects screen brightness; a higher luminous duty cycle results in a longer illumination duration and correspondingly higher screen brightness, while a lower luminous duty cycle results in a shorter illumination duration and lower screen brightness.

[0042] Optionally, depending on different screen brightness variations, the DDIC chip can either increase or decrease the luminous duty cycle of the EM cycle. Since human eye perception of brightness is a cumulative process, increasing the luminous duty cycle increases the cumulative brightness of the display within the EM cycle, resulting in a perceived increase in display brightness. Conversely, decreasing the luminous duty cycle decreases the cumulative brightness of the display within the EM cycle, resulting in a perceived decrease in display brightness.

[0043] Regarding the method of adjusting the emission duty cycle of the EM cycle, in one possible implementation, the DDIC chip can adjust the emission duty cycle within the EM cycle using pulse width modulation (PWM) technology. This application does not limit the specific adjustment method.

[0044] Figure 3 This is a schematic diagram illustrating the use of PWM technology to adjust the duty cycle of EM periodic emission. For example... Figure 3 As shown, when adjusting the emission duty cycle using PWM, a high level indicates the emission phase, and a low level indicates the off phase. PWM technology uses square waves for modulation, adjusting the emission duty cycle by varying the duration of the high and low levels. t1 to t5 represent the durations of two EM cycles. The first EM cycle is from t1 to t3, and the second cycle is from t3 to t5. The durations of the two EM cycles are the same, i.e., t3 - t1 = t5 - t3. Here, t1 to t2 is the emission phase, and t2 to t3 is the off phase. The emission duty cycle is the proportion of the emission duration to the total EM cycle duration. Figure 3 The duration of the first EM cycle is t2-t1, therefore, the duty cycle of the first EM cycle is t2-t1 / t3-t1, and the duty cycle of the second EM cycle is t4-t3 / t5-t3. After adjusting the duty cycle of the EM cycle through PWM, the high-level duration of the second EM cycle increases, thus making the duty cycle of the second EM cycle greater than that of the first EM cycle, i.e., t4-t3 / t5-t3 > t2-t1 / t3-t1.

[0045] Taking an LTPS display with an EM frequency of 360Hz as an example, Figure 4 Is Figure 1Based on the method provided in this application embodiment, after the DDIC chip adjusts the EM periodic emission duty cycle, a schematic diagram of the relationship between screen brightness and time is shown, with the horizontal axis representing time and the vertical axis representing screen brightness. Figure 4 The refresh rates, from top to bottom, are 120Hz, 90Hz, 60Hz, and 40Hz. Specifically, at a refresh rate of 120Hz, the DDIC chip increases the light emission duty cycle of the 2nd and 3rd EM cycles by extending the light emission duration within the 2nd and 3rd EM cycles; at a refresh rate of 90Hz, the DDIC chip increases the light emission duty cycle of the 2nd, 3rd, and 4th EM cycles by extending the light emission duration within the 2nd, 3rd, and 4th EM cycles; at a refresh rate of 60Hz, the DDIC chip increases the light emission duty cycle of the 2nd to 6th EM cycles by extending the light emission duration within the 2nd to 9th EM cycles; and at a refresh rate of 40Hz, the DDIC chip increases the light emission duty cycle of the 2nd to 9th EM cycles by extending the light emission duration within the 2nd to 9th EM cycles.

[0046] Because the luminous duty cycle of the EM cycle is increased, the brightness within each EM cycle is increased, thereby compensating for the decrease in brightness caused by screen leakage, keeping the screen brightness stable during EM scanning, and thus avoiding brightness jumps between adjacent image frames.

[0047] It should be noted that since the screen flicker perceived by the human eye is caused by changes in screen brightness, in this embodiment, during EM scanning, the luminous duty cycle of the EM cycle changes over time, so that the brightness difference of the cumulative brightness of the display screen in different EM cycles is within a certain range. This brightness difference is a brightness change that is imperceptible to the human eye. For example, during the display of a 255 grayscale image, the brightness change that the human eye can perceive is 0.8%. That is, the cumulative brightness change between adjacent EM cycles is imperceptible to the human eye if it is less than 0.8%, and perceptible if it exceeds 0.8%.

[0048] In summary, in this embodiment of the application, the DDIC chip adjusts the emission duty cycle of the EM cycle during EM scanning to adjust the emission duration within the EM cycle, thereby improving the stability of screen brightness during image display, avoiding flickering caused by changes in screen brightness, and helping to improve the image display quality of the display screen.

[0049] Furthermore, without the above solution, the minimum refresh rate supported by the display is usually relatively high in order to avoid excessive screen flicker. However, with the above EM cycle adjustment mechanism, the screen flicker problem can be alleviated, especially in low refresh rate scenarios. Therefore, the display can support even lower refresh rates, which on the one hand improves the display's frequency range, and on the other hand helps to reduce display power consumption during the display process.

[0050] In one possible implementation, the terminal stores a light emission duty cycle curve, which characterizes the correspondence between the light emission duty cycle and the EM period. The DDIC chip adjusts the light emission duty cycle based on this curve when adjusting the EM period.

[0051] It should be noted that the light emission duty cycle curve is generated based on the brightness change curve of the display screen at a specific frequency without adjusting the light emission duty cycle.

[0052] For example, the luminous duty cycle curve corresponding to 30Hz is generated based on the brightness change curve of the display screen at 30Hz without adjusting the luminous duty cycle; the luminous duty cycle curve corresponding to 60Hz is generated based on the brightness change curve of the display screen at 60Hz without adjusting the luminous duty cycle.

[0053] To accommodate different gray levels, in some embodiments, the emission duty cycle curve is generated based on multiple brightness change curves during the display of different gray level images at a specific frequency.

[0054] For example, taking a grayscale range of 0-255 and a grayscale step size of 10 (other step sizes can also be used), multiple brightness change curves are obtained during the process of displaying different grayscale images at 30Hz. The multiple brightness change curves are then fitted to obtain the target brightness change curve, and the luminous duty cycle curve corresponding to 30Hz is generated based on the target brightness change curve.

[0055] Optionally, the emission duty cycle curve is fixed in the DDIC chip and directly read and used by the DDIC chip; alternatively, the emission duty cycle curve is stored in the terminal's memory, from which the DDIC chip can read and use it. Furthermore, the emission duty cycle curve supports updates.

[0056] Since the DDIC chip refreshes the image periodically according to the refresh rate, in one possible implementation, the emission duty cycle curve is used to indicate the emission duty cycle of each EM cycle during the display of a single frame image.

[0057] In an illustrative example, when the EM frequency is 360Hz and the refresh rate is 60Hz, the luminous duty cycle curve is used to indicate the luminous duty cycle of 6 EM cycles during the display of a single frame image; when the EM frequency is 360Hz and the refresh rate is 30Hz, the luminous duty cycle curve is used to indicate the luminous duty cycle of 12 EM cycles during the display of a single frame image.

[0058] Regarding the generation method of the emission duty cycle curve, in one possible implementation, developers experiment with screen brightness variations under different emission duty cycles. Through multiple experiments, they obtain the emission duty cycle corresponding to each EM cycle. This emission duty cycle ensures that the screen brightness remains as consistent as possible, ultimately forming the emission duty cycle curve, which is then stored in the terminal. In operation, the DDIC chip reads the stored emission duty cycle curve and, based on the curve, adjusts the emission duty cycle of each EM cycle during EM scanning.

[0059] Optionally, the emission duty cycle curves may indicate different emission duty cycles for different EM periods, or some EM periods may have the same emission duty cycle while others may have different emission duty cycles.

[0060] For example, when the emission duty cycle curve indicates the emission duty cycle of 12 EM cycles, the emission duty cycles of the 12 EM cycles are different, or the emission duty cycles of odd EM cycles are the same, the emission duty cycles of even EM cycles are the same, and the emission duty cycles of odd EM cycles are different from those of even EM cycles.

[0061] Because different displays have different properties, their brightness variation curves are different, and consequently, their light emission duty cycle curves are different. The following explains several types of light emission duty cycle curves.

[0062] The correlation between the emission duty cycle and the EM period, as characterized by the emission duty cycle curve, can be categorized into several cases:

[0063] I. When the brightness variation curve represents the decrease in brightness over time, the luminous duty cycle curve, which represents the luminous duty cycle, shows a positive correlation with the EM period. The brightness variation curve is used to characterize the change in screen brightness over time.

[0064] The brightness change curve represents the decrease in brightness over time, meaning the screen brightness weakens as the EM cycle increases. In this case, it's necessary to appropriately increase the EM cycle's luminous duty cycle for brightness compensation. Furthermore, as the brightness decreases more severely, the required EM cycle's luminous duty cycle should also be increased appropriately to compensate for even greater brightness loss.

[0065] Taking an LTPS display with an EM frequency of 360Hz as an example, Figure 1 This diagram illustrates the relationship between screen brightness and time when the EM cycle duty cycle is not adjusted. Since the duty cycle is the same for each EM cycle, the screen brightness gradually decreases due to leakage current. The brightness change curve represents the decrease in brightness over time.

[0066] Figure 4 Is Figure 1Based on this, a schematic diagram illustrating the relationship between screen brightness and time after adjusting the duty cycle of EM periodic emission. Compared to... Figure 1 , Figure 4 The luminous duty cycle increases significantly during the EM cycle. As the EM cycle increases, the screen brightness decreases more and more, and the increase in luminous duty cycle should also increase more and more. For example, the luminous duty cycle is 20% without EM cycle adjustment. After adjusting the EM cycle luminous duty cycle, the duty cycle remains unchanged in the first cycle, is adjusted to 25% in the second cycle, 32% in the third cycle, and 42% in the fourth cycle. By increasing the EM cycle luminous duty cycle, the screen flicker problem caused by the decrease in screen brightness is avoided. It can be seen that the luminous duty cycle curve, representing the luminous duty cycle, is positively correlated with the EM cycle.

[0067] Second, when the brightness change curve represents the increase of brightness over time, the luminous duty cycle curve represents the luminous duty cycle which is negatively correlated with the EM period.

[0068] Because low-temperature polycrystalline oxide (LTPO) materials have low screen leakage current, they can maintain screen brightness well. Therefore, screen brightness increases with the increase of the EM cycle, and the brightness change curve represents the increase in brightness over time. However, the screen brightness also experiences a sudden drop from high to low, leading to screen flicker. In this case, when adjusting the EM cycle's luminous duty cycle, the luminous duty cycle should be appropriately reduced. Furthermore, as the EM cycle increases, the increase in screen brightness becomes more significant, and the reduction in the luminous duty cycle should gradually increase.

[0069] Taking an LTPO screen with an EM frequency of 360Hz as an example, Figure 5 This is a schematic diagram illustrating the relationship between screen brightness and time before adjusting the EM periodicity duty cycle at a refresh rate of 90Hz. The horizontal axis represents time, and the vertical axis represents screen brightness. Due to the characteristics of LTPO material, screen brightness gradually increases during EM scanning, and the brightness change curve represents the increase in brightness over time. When displaying K+1 frame images, a brightness jump (brightness changes from high to low) occurs due to brightness recovery.

[0070] Figure 6This diagram illustrates the relationship between screen brightness and time after adjusting the EM cycle's emission duty cycle. After adjustment, the emission duty cycle within the EM cycle is significantly reduced. As the EM cycle increases, the emission duty cycle continues to decrease, and the rate of decrease gradually increases. For example, the emission duty cycle without adjustment is 20%. After adjustment, the duty cycle remains unchanged in the first cycle, is adjusted to 18% in the second cycle, 14% in the third cycle, and 9% in the fourth cycle. By reducing the emission duty cycle, screen flicker caused by increased screen brightness is avoided.

[0071] Third, when the brightness change curve represents the brightness increasing with time in the first time interval and the brightness decreasing with time in the second time interval, the emission duty cycle curve represents the emission duty cycle being negatively correlated with the EM period in the first time interval and positively correlated with the EM period in the second time interval.

[0072] The emission duty cycle curve contains at least one first time interval and one second time interval, and the order of the first time interval and the second time interval is not limited.

[0073] In both of the above situations, the screen brightness and EM cycle show a unidirectional relationship. However, due to factors such as screen material or calibration method, the relationship between screen brightness and time may be irregular. There may be a phenomenon where the screen brightness increases in a certain period of time and decreases in another period of time.

[0074] Therefore, the first time interval can be defined as the period during which the brightness increases over time, represented by a continuous brightness change curve, and the second time interval can be defined as the period during which the brightness decreases over time. In the first time interval, the screen brightness decreases as the EM cycle increases, requiring an appropriate increase in the EM cycle's duty cycle for brightness compensation. In the second time interval, the screen brightness increases as the EM cycle increases, requiring an appropriate decrease in the EM cycle's duty cycle to prevent a continuous increase in screen brightness.

[0075] Both the first and second time intervals can contain multiple EM cycles. The following example, which shows that both the first and second time intervals contain 4 EM cycles, illustrates the relationship between the emission duty cycle curve and the EM cycle. Figure 7 This is a brightness change curve, illustrating the relationship between screen brightness and time before EM cycle duty cycle adjustment when the brightness change is irregular. Specifically, the first to fourth EM cycles are defined as the first time interval, during which screen brightness increases over time; the fifth to eighth EM cycles are defined as the second time interval, during which brightness decreases over time. Figure 8The brightness variation curve illustrates the relationship between screen brightness and time when the brightness change is irregular. After adjusting the EM cycle's duty cycle, the curve shows that in the first time interval after adjusting the EM cycle's duty cycle, the screen brightness remains constant by gradually decreasing the duty cycle. Therefore, the duty cycle curve indicates a negative correlation between the duty cycle and the EM cycle in the first time interval. In the second time interval, the EM cycle's duty cycle is increased. It can be seen that the duty cycle continuously increases with the increase of the EM cycle. With the EM cycle remaining constant, the duty cycle gradually increases, indicating a positive correlation between the duty cycle and the EM cycle in the second time interval.

[0076] Screen material and calibration method are two inherent factors affecting screen brightness changes and cannot be adjusted during screen use. However, screen brightness changes are not only related to these two inherent factors but may also be related to the screen's real-time operating status, such as screen brightness and screen refresh rate. Furthermore, multiple emission duty cycle curves may exist. Therefore, when adjusting the emission duty cycle of the EM cycle during EM scanning based on the emission duty cycle curve, the DDIC chip should select a suitable emission duty cycle curve as the adjustment basis.

[0077] In one possible implementation, the DDIC chip determines the emission duty cycle curve based on the current display parameters. Different display parameters correspond to different emission duty cycle curves. The display parameters include at least one of refresh rate and screen brightness.

[0078] Figure 9 This is a flowchart illustrating an image display method provided in another exemplary embodiment of this application. The method includes:

[0079] Step 901: Determine the emission duty cycle curve based on the current display parameters.

[0080] Different display parameters correspond to different light emission duty cycle curves. Display parameters include at least one of refresh rate and screen brightness.

[0081] In one possible implementation, when the display parameters include refresh rate, the number of refresh rates supported by the screen is equal to the number of emission duty cycle curves. For example, if a screen supports four refresh rates—40Hz, 60Hz, 90Hz, and 120Hz—testing in each of these four cases will yield four emission duty cycle curves.

[0082] In another possible implementation, when the display parameters include screen brightness, the number of settable screen brightness levels is equivalent to the number of emission duty cycle curves. For example, a certain screen may have three adjustable brightness levels: 0 nit-250 nit, 250 nit-350 nit, and 350 nit-500 nit. By testing at these three brightness levels, three emission duty cycle curves can be obtained.

[0083] In another possible implementation, when the display parameters include both screen brightness and refresh rate, the total number of possible combinations of these two parameters represents the number of luminous duty cycle curves. For example, a screen supports four refresh rates: 40Hz, 60Hz, 90Hz, and 120Hz. This screen also has three adjustable brightness levels: 0nit-250nit, 250nit-350nit, and 350nit-500nit. In this case, there are 12 possible combinations of these two parameters. Experiments are conducted on each combination, and each combination yields a corresponding luminous duty cycle curve, totaling 12 curves, as shown in Table 1.

[0084]

[0085] Table 1

[0086] In an illustrative example, when the current screen brightness is 270 nits and the refresh rate is 60Hz, based on these two display parameters and the correspondence in Table 1, the DDIC chip determines that the 5th emission duty cycle curve is the emission duty cycle curve under the current display parameter conditions.

[0087] Step 902: Adjust the emission duty cycle of the EM cycle during the EM scanning process based on the emission duty cycle curve.

[0088] The embodiment of this application determines the light emission duty cycle curve based on the current display parameters. Of course, the light emission duty cycle curve can also be determined based on other factors or their combination. This embodiment of the application does not limit this.

[0089] In this embodiment, the DDIC chip determines the appropriate light emission duty cycle curve for the current display scenario from several candidate light emission duty cycle curves based on real-time display parameters. Then, it adjusts the light emission duty cycle of the EM cycle based on the light emission duty cycle curve, which helps to improve the stability of screen brightness in different display scenarios and thus solves the problem of screen flicker in various display scenarios.

[0090] In practical applications, refresh rate is an important factor affecting screen brightness, such as... Figure 1As shown, at a lower refresh rate, there are more EM cycles during the display of a single frame, resulting in a greater degree of screen brightness decay and more pronounced brightness jumps. Conversely, at a higher refresh rate, the screen brightness decay is smaller, and the resulting screen flicker is not severe and may not be perceptible to the human eye in practical applications.

[0091] It is evident that brightness compensation is more necessary at low refresh rates, and the embodiments of this application demonstrate a more significant effect. Therefore, in one possible implementation, when the current refresh rate is less than the refresh rate threshold, during the display of the Kth frame image, the DDIC chip adjusts the luminous duty cycle of the EM cycle during EM scanning based on the current display parameters.

[0092] Optionally, if the current refresh rate is greater than the refresh rate threshold, the DDIC chip can perform EM scanning according to the original emission duty cycle.

[0093] In an illustrative example, the refresh rate threshold is set to 90Hz. When the refresh rate is less than 90Hz, the DDIC chip performs the steps in this embodiment of the application. When the refresh rate is greater than 90Hz, the method provided in this embodiment is not performed.

[0094] Of course, the refresh rate threshold can also be set to other values, such as 60Hz, 120Hz, etc., and the embodiments of this application do not constitute a limitation thereto.

[0095] In this embodiment, DDIC determines whether the light emission duty cycle of the EM cycle needs to be adjusted at the current refresh rate based on the refresh rate threshold. When the refresh rate is high, the screen brightness will not have a large jump. Therefore, the light emission duty cycle of the EM cycle does not need to be adjusted, which can reduce power consumption.

[0096] In one possible implementation, the DDIC chip can adjust the emission duty cycle of each EM cycle during the EM scan based on the current display parameters.

[0097] Figure 4 The method shown for adjusting the EM cycle duty cycle refers to adjusting the EM cycle duty cycle during EM scanning. This is suitable for low refresh rates, ensuring that the screen brightness remains as consistent as possible in each EM cycle.

[0098] However, at higher EM frequencies, the EM cycles are quite dense during single-frame image display. Adjusting each EM cycle would incur significant overhead. Therefore, in another possible implementation, the DDIC chip adjusts the emission duty cycle of a specified EM cycle during EM scanning.

[0099] In some embodiments, DDIC adjusts the emission duty cycle of a specified EM period during EM scanning based on a target period interval.

[0100] The time interval between adjacent specified EM cycles is the target cycle interval.

[0101] The EM frequency is relatively high, and the EM cycles are also relatively dense. At this time, a suitable target cycle interval can be preset. In an illustrative example, there are N EM cycles in the display of a single frame image. The preset target interval is i. With the initial adjustment cycle being the a-th cycle, the emission duty cycle of the a-th cycle, the a+i+1-th cycle, the a+2(i+1)-th cycle, ..., the a+n(i+1)-th cycle (n = 1, 2, 3...) is adjusted during the image scanning process, and a+n(i+1)≤N.

[0102] like Figure 10 As shown, taking an LTPS screen with an EM frequency of 360Hz as an example, assuming a refresh rate of 40Hz, there are 9 EM cycles in the display of a single frame image, from cycle 1 to cycle 9. If the target cycle interval is set to 1, then the EM cycle duty cycle is adjusted once every EM cycle, that is, the duty cycle is adjusted for cycles 2, 4, 6, and 8 respectively. In this way, although there is still a decrease in screen brightness in some EM cycles, the brightness decrease can be reduced by reasonably presetting the target cycle interval, thus alleviating the phenomenon of screen flicker.

[0103] It should be noted that when the DDIC chip adjusts the EM periodic emission duty cycle based on the target period interval, any EM period can be selected as the starting period for adjustment.

[0104] In this embodiment, the DDIC chip adjusts the duty cycle of a specified EM cycle according to the target period interval. This allows the embodiment to adjust the duty cycle of a specific EM cycle based on the actual brightness change curve. Since the EM frequency is high, multiple EM cycle duty cycles need to be adjusted when compensating for screen brightness, resulting in significant overhead. The method shown in this embodiment effectively reduces overhead and lowers power consumption.

[0105] It should be noted that the above embodiments use LTPO screens or LTPS screens as examples for illustration. In other possible ways, it can also be used for other types of self-emissive displays, such as oxide displays. This application embodiment does not limit this.

[0106] This application embodiment also provides a DDIC chip, the DDIC chip being used for:

[0107] During the display of the Kth frame image, the emission duty cycle of the EM cycle during the EM scan is adjusted based on the current display parameters. The emission duty cycle refers to the proportion of the emission time within the EM cycle. The EM cycle includes an emission phase and an off phase, and K is a positive integer.

[0108] In some embodiments, the DDIC chip is used for:

[0109] The luminous duty cycle curve is determined based on the current display parameters. The luminous duty cycle curve is used to characterize the correspondence between the luminous duty cycle and the EM period. Different display parameters correspond to different luminous duty cycle curves. The display parameters include at least one of refresh rate and screen brightness.

[0110] The emission duty cycle of the EM cycle during the EM scanning process is adjusted based on the emission duty cycle curve.

[0111] In some embodiments, the light emission duty cycle curve is generated based on the brightness change curve of the display screen at a specific frequency without adjusting the light emission duty cycle.

[0112] In some embodiments, when the brightness change curve represents the decrease in brightness over time, the luminous duty cycle curve represents the luminous duty cycle that is positively correlated with the EM period.

[0113] When the brightness change curve represents the increase in brightness over time, the luminous duty cycle curve represents the luminous duty cycle which is negatively correlated with the EM period.

[0114] When the brightness change curve represents the brightness increasing with time in the first time interval and the brightness decreasing with time in the second time interval, the emission duty cycle curve represents the emission duty cycle being negatively correlated with the EM period in the first time interval and positively correlated with the EM period in the second time interval.

[0115] In some embodiments, the DDIC chip is used for:

[0116] Adjust the emission duty cycle of each EM cycle during the EM scanning process;

[0117] or,

[0118] Adjust the emission duty cycle of the specified EM cycle during the EM scanning process.

[0119] In some embodiments, the DDIC chip is used for:

[0120] Based on the target period interval, the emission duty cycle of the specified EM cycle during the EM scanning process is adjusted, wherein the time interval between adjacent specified EM cycles is the target period interval.

[0121] In some embodiments, the DDIC chip is further used for:

[0122] Upon completion of the image scanning of the Kth frame, the emission duty cycle of the EM cycle during the EM scanning process is adjusted based on the current display parameters;

[0123] Before scanning the K+1th frame, the emission duty cycle of the EM cycle is adjusted to its initial value.

[0124] In some embodiments, the DDIC chip is used for:

[0125] When the current refresh rate is less than the refresh rate threshold, during the display of the Kth frame image, the emission duty cycle of the EM cycle during the EM scan is adjusted based on the current display parameters.

[0126] In some embodiments, the DDIC chip is used for low-temperature polycrystalline silicon (LTPS) displays, low-temperature polycrystalline oxide (LTPO) displays, or oxide displays.

[0127] In some embodiments, the light emission duty cycle of the EM cycle changes over time during the EM scanning process, so that the brightness difference of the cumulative brightness of the display screen in different EM cycles is within the difference range.

[0128] Furthermore, this application embodiment also provides a display module, which includes a display screen and a DDIC chip. The DDIC chip is used to drive the display screen and to implement the image display methods provided in the above-described method embodiments.

[0129] Figure 11 This illustration shows a structural block diagram of a terminal 1300 provided in an exemplary embodiment of this application. The terminal 1300 may be a smartphone, tablet computer, laptop computer, etc. The terminal 1300 in this application may include one or more of the following components: AP 1310, display screen 1320, and DDIC chip 1330.

[0130] The AP1310 may include one or more processing cores. The AP1310 connects to various parts within the terminal 1300 using various interfaces and lines, and performs various functions and processes data by running or executing instructions, programs, code sets, or instruction sets stored in memory. Optionally, the AP1310 may be implemented using at least one of the following hardware forms: Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). The AP1310 may integrate one or more of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), Neural-network Processing Unit (NPU), and modem.

[0131] In this embodiment, the display screen is 1320. The display screen 1320 can be an LTPS display screen, an LTPO display screen, or an Oxide display screen.

[0132] The DDIC chip 1330 is used to drive the display screen 1320 to display images, and the DDIC chip 1330 is used to implement the image display methods provided in the above embodiments. In addition, the DDIC chip 1330 is connected to the AP 1310 through the Mobile Industry Processor Interface (MIPI) to receive image data and instructions issued by the AP 1310.

[0133] In addition, those skilled in the art will understand that the structure of the terminal 1300 shown in the above figures does not constitute a limitation on the terminal 1300. The terminal may include more or fewer components than shown, or combine certain components, or have different component arrangements. For example, the terminal 1300 also includes components such as a microphone, speaker, radio frequency circuit, input unit, sensor, audio circuit, Wireless Fidelity (WiFi) module, power supply, and Bluetooth module, which will not be described in detail here.

[0134] It should be understood that "multiple" as used herein refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. Furthermore, the step numbers described herein are merely illustrative of one possible execution order. In some other embodiments, the steps may not be executed in numerical order, such as two steps with different numbers being executed simultaneously, or two steps with different numbers being executed in the reverse order of the illustration. This application does not limit this.

[0135] Those skilled in the art will recognize that the functions described in the embodiments of this application in one or more of the above examples can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0136] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An image display method, characterized in that, The method is used for a display driver circuit DDIC chip in a display screen, and the method includes: During the display of the Kth frame image, the luminous duty cycle curve is determined based on the current display parameters. The luminous duty cycle curve is used to characterize the correspondence between the luminous duty cycle and the EM period. Different display parameters correspond to different luminous duty cycle curves. The luminous duty cycle curve is generated based on the brightness change curve of the display screen at a specific frequency without adjusting the luminous duty cycle. The luminance duty cycle of the EM scan is adjusted based on the luminance duty cycle curve. The luminance duty cycle refers to the proportion of the luminance duration within the EM cycle. The EM cycle includes a luminance phase and a shutdown phase. K is a positive integer. After adjustment, the luminance duty cycle of different EM cycles is different. Alternatively, the luminance duty cycle of some EM cycles is the same and the luminance duty cycle of some EM cycles is different, so that the brightness difference of the cumulative brightness of the display screen in different EM cycles is within the difference range.

2. The method according to claim 1, characterized in that, The display parameters include at least one of refresh rate and screen brightness.

3. The method according to claim 1, characterized in that, When the brightness change curve represents the decrease in brightness over time, the luminous duty cycle curve represents the luminous duty cycle which is positively correlated with the EM period. When the brightness change curve represents the increase in brightness over time, the luminous duty cycle curve represents the luminous duty cycle which is negatively correlated with the EM period. When the brightness change curve represents the brightness increasing with time in the first time interval and the brightness decreasing with time in the second time interval, the emission duty cycle curve represents the emission duty cycle being negatively correlated with the EM period in the first time interval and positively correlated with the EM period in the second time interval.

4. The method according to claim 1, characterized in that, Adjusting the emission duty cycle of the EM cycle during EM scanning includes: Adjust the emission duty cycle of each EM cycle during the EM scanning process; or, Adjust the emission duty cycle of the specified EM cycle during the EM scanning process.

5. The method according to claim 4, characterized in that, Adjusting the emission duty cycle of a specified EM period during the EM scanning process includes: Based on the target period interval, the emission duty cycle of the specified EM cycle during the EM scanning process is adjusted, wherein the time interval between adjacent specified EM cycles is the target period interval.

6. The method according to any one of claims 1 to 5, characterized in that, Adjusting the emission duty cycle of the EM cycle during EM scanning includes: Upon completion of the image scanning of the Kth frame, the emission duty cycle of the EM cycle during the EM scanning process is adjusted. The method further includes: Before scanning the K+1th frame, the emission duty cycle of the EM cycle is adjusted to its initial value.

7. The method according to any one of claims 1 to 5, characterized in that, Adjusting the emission duty cycle of the EM cycle during EM scanning includes: When the current refresh rate is less than the refresh rate threshold, during the display of the Kth frame image, the emission duty cycle of the EM cycle during the EM scan is adjusted.

8. The method according to any one of claims 1 to 5, characterized in that, The display screen is a low-temperature polycrystalline silicon (LTPS) display screen, a low-temperature polycrystalline oxide (LTPO) display screen, or an oxide display screen.

9. The method according to any one of claims 1 to 5, characterized in that, The emission duty cycle of the EM cycle changes over time during the EM scanning process.

10. A display driver circuit DDIC chip, characterized in that, The DDIC chip is applied to the display screen, and the DDIC chip is used for: During the display of the Kth frame image, the luminous duty cycle curve is determined based on the current display parameters. The luminous duty cycle curve is used to characterize the correspondence between the luminous duty cycle and the EM period. Different display parameters correspond to different luminous duty cycle curves. The luminous duty cycle curve is generated based on the brightness change curve of the display screen at a specific frequency without adjusting the luminous duty cycle. The luminance duty cycle of the EM scan is adjusted based on the luminance duty cycle curve. The luminance duty cycle refers to the proportion of the luminance duration within the EM cycle. The EM cycle includes a luminance phase and a shutdown phase. K is a positive integer. After adjustment, the luminance duty cycle of different EM cycles is different. Alternatively, the luminance duty cycle of some EM cycles is the same and the luminance duty cycle of some EM cycles is different, so that the brightness difference of the cumulative brightness of the display screen in different EM cycles is within the difference range.

11. The DDIC chip according to claim 10, characterized in that, The display parameters include at least one of refresh rate and screen brightness.

12. The DDIC chip according to claim 10, characterized in that, When the brightness change curve represents the decrease in brightness over time, the luminous duty cycle curve represents the luminous duty cycle which is positively correlated with the EM period. When the brightness change curve represents the increase in brightness over time, the luminous duty cycle curve represents the luminous duty cycle which is negatively correlated with the EM period. When the brightness change curve represents the brightness increasing with time in the first time interval and the brightness decreasing with time in the second time interval, the emission duty cycle curve represents the emission duty cycle being negatively correlated with the EM period in the first time interval and positively correlated with the EM period in the second time interval.

13. The DDIC chip according to claim 10, characterized in that, The DDIC chip is used for: Adjust the emission duty cycle of each EM cycle during the EM scanning process; or, Adjust the emission duty cycle of the specified EM cycle during the EM scanning process.

14. The DDIC chip according to claim 13, characterized in that, The DDIC chip is used for: Based on the target period interval, the emission duty cycle of the specified EM cycle during the EM scanning process is adjusted, wherein the time interval between adjacent specified EM cycles is the target period interval.

15. The DDIC chip according to any one of claims 10 to 14, characterized in that, The DDIC chip is also used for: Upon completion of the image scanning of the Kth frame, the emission duty cycle of the EM cycle during the EM scanning process is adjusted. Before scanning the K+1th frame, the emission duty cycle of the EM cycle is adjusted to its initial value.

16. The DDIC chip according to any one of claims 10 to 14, characterized in that, The DDIC chip is used for: When the current refresh rate is less than the refresh rate threshold, during the display of the Kth frame image, the emission duty cycle of the EM cycle during the EM scan is adjusted.

17. The DDIC chip according to any one of claims 10 to 14, characterized in that, The DDIC chip is used for low-temperature polycrystalline silicon (LTPS) displays, low-temperature polycrystalline oxide (LTPO) displays, or oxide displays.

18. The DDIC chip according to any one of claims 10 to 14, characterized in that, The emission duty cycle of the EM cycle changes over time during the EM scanning process.

19. A display module, characterized in that, The display module includes a display screen and a display driver circuit DDIC chip. The DDIC chip is used to drive the display screen and to implement the image display method as described in any one of claims 1 to 9.

20. A terminal, characterized in that, The terminal includes an application processor (AP), a display screen, and a display driver circuit (DDIC) chip. The AP and the DDIC chip are connected via a Mobile Industry Processor Interface (MIPI). The DDIC chip is used to implement the image display method as described in any one of claims 1 to 9.

Images