WO2023071614A1 - Light emission control method and system for micro display screen based on led - Google Patents

Abstract

Provided in the present application are a light emission control method and system for a micro display screen based on an LED. The method comprises: determining the maximum light emission duration and the minimum light emission duration according to an attribute of a micro display screen and the data bit width of a brightness value of a light-emitting pixel; then determining a current change parameter by combining a brightness value corresponding to full darkness and a brightness value corresponding to full brightness, wherein the change speed of a current value is not constantly equal to 0; according to the current change parameter, generating a current value corresponding to each moment in the maximum light emission duration, and correspondingly generating a light emission current; then determining a turn-off duration of the light-emitting pixel by combining a target brightness value of the light-emitting pixel; and finally, making, by using the light emission current, the light-emitting pixel start emitting light from the start moment of the maximum light emission duration, and stop emitting light after the turn-off duration. In the whole method, the actual brightness of a light-emitting pixel is controlled by means of combining a current value with a light emission time; therefore, the method has high precision and simple hardware implementation, and can better meet the requirements of higher grayscale levels.

Description

Lighting control method and system for LED-based micro-display

The present invention claims the priority of the Chinese patent application with the application number 202111243830.3 and the title of the invention "A Lighting Control Method and System for LED-Based Micro Display" submitted to the China Patent Office on October 26, 2021. The entire contents are hereby incorporated by reference.

technical field

The present application relates to the field of display technology, in particular to a lighting control method and system for an LED-based micro display screen.

Background technique

LED (Light Emitting Diode, light-emitting diode) refers to a solid-state semiconductor device that can convert electrical energy into visible light. LED-based micro-display refers to a micron-scale LED array that is highly integrated on a substrate based on LED technology, where each micron-scale LED acts as an independent light-emitting pixel. The actual brightness of the LED-based micro-display It is determined by the actual brightness of all the light-emitting pixels. The more gray levels of the light-emitting pixels (the number of gray levels indicates the difference in brightness, which is usually consistent with the brightness change felt by the human eye), the more the display effect of the image on the micro-display will be. more realistic. However, the human eye perception and the actual brightness of the light-emitting pixels usually have a nonlinear relationship. When the actual brightness is brighter, the actual brightness needs to change greatly to be recognized by the human eye. Therefore, in order to increase the number of gray levels of the light-emitting pixels, The light-emitting mode of the light-emitting pixels needs to be adjusted.

Since the actual brightness of the light-emitting pixel is proportional to the current, the actual brightness of the light-emitting pixel can usually be adjusted by the value of the current sent to the light-emitting pixel. That is to say, in order to increase the number of gray levels of the light-emitting pixel, the current needs to be extremely Precise control, however, it is difficult to implement high-precision current control in terms of hardware, so the existing light-emitting methods of light-emitting pixels cannot meet the requirements of higher gray levels.

Contents of the invention

The present application provides a light emitting control method and system of an LED-based micro display screen, which can be used to solve the technical problem that the existing light emitting mode of light emitting pixels cannot meet the requirement of higher gray levels.

In the first aspect, an embodiment of the present application provides a light emission control method of an LED-based micro-display, the light emission control method is used to control the light-emitting mode of any light-emitting pixel in the LED-based micro-display, including:

According to the playing frame rate of the micro-display screen and the number of rows of the luminous pixel array, determine the maximum duration of light emission of the target luminous pixel, and the target luminous pixel is any luminous pixel in the micro-display screen;

According to the data bit width of the candidate luminance value of each luminous pixel in each frame in the micro-display screen, and the maximum luminous duration, determine the minimum luminous duration of the target luminous pixel;

According to the first preset brightness value corresponding to full darkness, the second preset brightness value corresponding to full brightness, the maximum lighting duration and the minimum lighting duration, the current change parameter is determined, and the current variation parameter includes the current change parameter corresponding to the initial moment. The initial current value, the termination current value corresponding to the termination moment, and the change speed of the current value, the initial moment is the start moment of the maximum lighting duration, the termination moment is the end moment of the maximum lighting duration, and the current value The rate of change of is not always equal to zero;

Generate current values corresponding to each moment in the maximum lighting duration according to the current change parameter;

According to the target luminance value of the target luminous pixel in the current frame and the current value corresponding to each moment in the maximum luminous duration, determine the off duration of the target luminous pixel in the current frame;

time aligning the start moment of the target light-emitting pixel to emit light with the start moment of the maximum light-emitting duration;

Generate a luminous current that matches the current value corresponding to each moment in the maximum luminous duration, and send it to the target luminous pixel, so that the target luminous pixel starts to emit light from the starting moment;

Starting from the starting moment, the light-emitting current is turned off after the off-time period, so that the target light-emitting pixel stops emitting light.

With reference to the first aspect, in an implementable manner of the first aspect, the generating the current value corresponding to each moment in the maximum lighting duration according to the current change parameter includes:

Generate a fitting curve of the current value changing with time according to the maximum duration of light emission, the initial current value corresponding to the initial moment, the termination current value corresponding to the termination moment, and the change speed of the current value;

The current value corresponding to each moment in the maximum lighting duration is obtained from the fitting curve.

With reference to the first aspect, in an implementable manner of the first aspect, the target light-emitting pixel is determined according to the target brightness value of the target light-emitting pixel in the current frame and the current value corresponding to each moment in the maximum light-emitting duration. The off-time of pixels in the current frame, including:

Integrating the fitting curve over the candidate duration to obtain an integration result, the candidate duration being the time interval between any moment in the maximum luminous duration and the starting moment;

Acquiring a target integration result whose value is equal to the target luminance value of the target luminescent pixel in the current frame;

The target candidate duration corresponding to the target integration result is determined as the off duration of the target luminous pixel in the current frame.

In conjunction with the first aspect, in a possible implementation of the first aspect, the determination of the maximum light-emitting duration of the target light-emitting pixel according to the playback frame rate of the micro-display screen and the number of rows of the light-emitting pixel array includes:

Determine the playing time of a single frame according to the playing frame rate of the miniature display screen;

According to the number of rows of the luminous pixel array and the playback duration of the single frame, determine the single row scanning duration of each row of luminous pixels;

Any target duration is intercepted from the single-row scanning duration, and the target duration is determined as the maximum light-emitting duration of the target light-emitting pixel.

With reference to the first aspect, in an implementable manner of the first aspect, the time alignment of the starting moment of the target light-emitting pixel emitting light with the starting moment of the maximum light-emitting duration includes:

Obtain a preset sync signal;

Aligning the start time of the target light-emitting pixel to emit light and the start time of the maximum light-emitting duration with the start time of the synchronization signal respectively.

In the second aspect, the embodiment of the present application provides an LED-based micro-display light emission control system, the light emission control system is used to control the light-emitting mode of any light-emitting pixel in the LED-based micro-display, including a grayscale modulation circuit , current control circuit, time control circuit, line scanning synchronization circuit, controlled current source and control switch;

The gray scale modulation circuit is respectively connected to the current control circuit, the time control circuit and the row scanning synchronization circuit, and the row scanning synchronization circuit is also connected to the current control circuit and the time control circuit respectively, The current control circuit is connected to the controlled current source, and the control switch is respectively connected to the controlled current source, the target luminous pixel and the time control circuit, and the target luminous pixel is the Any light-emitting pixel;

The gray-scale modulation circuit is used to determine the maximum duration of light emission of the target light-emitting pixel according to the playback frame rate of the micro-display screen and the number of rows of the light-emitting pixel array; The data bit width of the candidate brightness value of each frame, and the maximum duration of light emission, determine the minimum duration of light emission of the target light-emitting pixel; and, according to the first preset brightness value corresponding to full darkness and the second preset brightness corresponding to full brightness Value, the maximum light-emitting time length and the light-emitting minimum time length, determine the current change parameters, the current change parameters include the initial current value corresponding to the initial moment, the termination current value corresponding to the termination time, and the change speed of the current value, the initial The moment is the start moment of the maximum duration of light emission, and the end moment is the end moment of the maximum duration of light emission;

The current control circuit is configured to generate a current value corresponding to each moment in the maximum lighting duration according to the current change parameter;

The gray-scale modulation circuit is further configured to determine whether to turn off the target luminous pixel in the current frame according to the target luminance value of the target luminous pixel in the current frame and the current value corresponding to each moment in the maximum light-emitting duration. duration;

The row scanning synchronization circuit is used to time-align the start moment of the target light-emitting pixel with the start moment of the maximum light-emitting duration;

The controlled current source is used to generate a light-emitting current that matches the current value corresponding to each moment in the maximum light-emitting duration, and send it to the target light-emitting pixel, so that the target light-emitting pixel starts from the start start to shine all the time;

The time control circuit is configured to control the control switch to turn off the luminescence current after the off period from the start moment, so that the target luminescence pixel stops emitting light.

With reference to the second aspect, in an implementable manner of the second aspect, the current control circuit includes:

A fitting curve generating module, configured to generate a curve of the current value changing over time according to the maximum lighting duration, the initial current value corresponding to the initial moment, the termination current value corresponding to the termination moment, and the change speed of the current value. Curve fitting;

The current value acquisition module is configured to acquire the current value corresponding to each moment in the maximum lighting duration from the fitting curve.

With reference to the second aspect, in an implementable manner of the second aspect, the grayscale modulation circuit includes:

An integration result acquisition module, configured to integrate the fitting curve over a candidate time length to obtain an integration result, the candidate time length being the time interval between any moment in the maximum light-emitting time and the starting point;

A target integration result acquisition module, configured to acquire a target integration result whose value is equal to the target luminance value of the target luminescent pixel in the current frame;

The off-duration determining module is configured to determine the target candidate duration corresponding to the target integration result as the off-duration of the target luminescent pixel in the current frame.

With reference to the second aspect, in an implementable manner of the second aspect, the grayscale modulation circuit includes:

The playback duration determination module is used to determine the playback duration of a single frame according to the playback frame rate of the micro display screen;

A single-row scanning duration determining module, configured to determine the single-row scanning duration of each row of luminous pixels according to the number of rows of the luminous pixel array and the playback duration of the single frame;

The maximum luminescence duration determining module is configured to intercept any target duration from the single-row scanning duration, and determine the target duration as the maximum luminescence duration of the target luminous pixel.

With reference to the second aspect, in an implementable manner of the second aspect, the row scan synchronization circuit includes:

A synchronous signal acquisition module, configured to acquire a preset synchronous signal;

The alignment module is configured to align the starting moment of the target light-emitting pixel to emit light and the starting moment of the maximum light-emitting duration with the starting moment of the synchronization signal respectively.

In this way, the embodiment of the present application discloses an LED-based micro-display light emission control method, according to the micro-display's own properties and the data bit width of each light-emitting pixel's candidate brightness value in each frame, determine the brightness of each light-emitting pixel After the maximum light-emitting time and the minimum light-emitting time, the current change parameter is determined by combining the first preset brightness value corresponding to full darkness and the second preset brightness value corresponding to full brightness, wherein the change speed of the current value is not always equal to zero, according to The current change parameter generates the current value corresponding to each moment in the maximum light-emitting time, and then combines the target brightness value of each light-emitting pixel in the current frame to determine the off-time of the light-emitting pixel in the current frame, and the starting time of each light-emitting pixel to emit light Time-align with the starting point of the maximum light-emitting duration, and generate a light-emitting current that matches the current value corresponding to each moment in the maximum light-emitting time, so that the light-emitting pixels start to emit light from the initial moment, and turn off the light-emitting current after the turn-off time , so that the light-emitting pixel stops emitting light. The whole method precisely controls the actual brightness of the luminous pixels through the combination of the current value and the luminous time, so that the difference between the actual luminances of the luminous pixels can be recognized by the human eye in time, with high precision and relatively simple hardware implementation, which can be compared It satisfies the requirement of higher number of gray scales well.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments described in this application. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic diagram of the relationship between the perceived brightness of the human eye, the actual brightness of the light-emitting pixel, and the current value input by the light-emitting pixel provided by the embodiment of the present application;

FIG. 2 is a schematic diagram of the overall process corresponding to a lighting control method for an LED-based micro-display provided in an embodiment of the present application;

FIG. 3a is a schematic diagram of a ramp current provided by the embodiment of the present application;

Figure 3b is a schematic diagram of the change speed curves of various current values provided by the embodiment of the present application;

Fig. 4a is a schematic diagram of the light-emitting mode of the target light-emitting pixel provided in the embodiment of the present application;

Fig. 4b is a schematic diagram of a light emitting mode of a plurality of light emitting pixels provided in the embodiment of the present application;

FIG. 5 is a schematic diagram of the overall structure of an LED-based micro-display lighting control system provided in an embodiment of the present application;

Fig. 6a is a specific structural schematic diagram of an LED-based micro-display lighting control system provided by an embodiment of the present application;

Fig. 6b is another specific structural schematic diagram of an LED-based micro-display lighting control system provided by an embodiment of the present application.

Detailed ways

The present invention will be described in detail below in conjunction with various embodiments shown in the drawings. However, these embodiments do not limit the present invention, and structural, method, or functional changes made by those skilled in the art according to these embodiments are included in the protection scope of the present invention.

In order to solve the technical problem that the existing light-emitting mode of light-emitting pixels cannot meet the requirement of higher gray levels, the present application discloses a light-emitting control method of an LED-based micro-display through the following embodiments. The luminescence control method provided in the embodiment of the present application is used to control the luminescence mode of any luminous pixel in an LED-based micro-display. A micro-display usually includes a plurality of luminous pixels arranged in an array. The actual brightness of the LED usually presents a non-linear relationship. Figure 1 exemplarily shows the schematic diagram of the relationship between the perceived brightness of the human eye, the actual brightness of the light-emitting pixel, and the current value input by the light-emitting pixel provided by the embodiment of the present application, as shown in Figure 1 , the nonlinear relationship between the perceived brightness of the human eye and the actual brightness of the light-emitting pixel can be expressed by the following formula (1):

L _OUT = L _IN ^γ formula (1)

In formula (1), L _out is the perceived brightness of human eyes, L _IN is the actual brightness of the light-emitting pixel, and γ is the preset index.

Since there is a linear relationship between the actual luminance of the luminous pixel and the current value, the measured grayscale value (that is, the brightness perceived by the human eye) and the current value input by the luminous pixel (corresponding to the input physical luminance data) usually show γ<1 If the value of γ is not corrected, the details of the dark part of the display will be compressed, and the gray scale will be lost. If you want the human eye to experience a linear response to the brightness and current, that is, the input physical brightness is the same as the human eye’s perception of brightness, you need to perform gamma correction, and the coefficient of gamma correction is 1/2.2.

Fig. 2 exemplarily shows a schematic diagram of the overall flow corresponding to a lighting control method for an LED-based micro-display provided in an embodiment of the present application, which specifically includes the following steps:

Step 201: Determine the maximum light-emitting duration of the target light-emitting pixel according to the playing frame rate of the micro-display and the number of rows of the light-emitting pixel array.

Wherein, the target luminous pixel is any luminous pixel in the micro-display.

Further, the maximum duration of light emission of the target light-emitting pixel can be determined in the following manner:

First, determine the playing time of a single frame according to the playing frame rate of the micro-display.

Next, according to the number of rows of the luminous pixel array and the playback duration of a single frame, the single-row scanning duration of each row of luminous pixels is determined.

Finally, any target duration is intercepted from the single-line scanning duration, and the target duration is determined as the maximum luminescence duration of the target luminous pixel.

Exemplarily, the playback frame rate is 100Hz, and the light-emitting pixel array of the micro-display is 1280×1024. Then, the playing time of a single frame of the micro-display is 10 ms, and the single-row scanning time of each row of light-emitting pixels is about 7.8 μs, which can be obtained from 7.8 Any target duration is intercepted in μs, and it is used as the maximum luminescence duration of the target luminous pixel.

Step 202, according to the data bit width of the candidate luminance value of each luminous pixel in each frame in the micro-display screen, and the maximum luminous duration, determine the minimum luminous duration of the target luminous pixel.

Further, according to the data bit width of the candidate luminance value of each light-emitting pixel in each frame in the micro-display, determine the number of different luminance values that can be represented by the data bit width, and then divide the maximum luminous duration by the data bit width. The number of different luminance values represented by , to get the minimum luminescence duration of the luminous pixel.

Exemplarily, the data bit width of the candidate luminance value of the target luminescent pixel in each frame is 8 bits (binary digit, bit), then the number of different luminance values that can be represented by the data bit width is 2 ⁸ =256, assuming that the maximum luminescence If the duration is 10μs, the minimum duration of light emission is 10μs/256, which is approximately equal to 30ns.

Step 203: Determine the current change parameter according to the first preset brightness value corresponding to full darkness, the second preset brightness value corresponding to full brightness, the maximum lighting duration, and the minimum lighting duration.

Wherein, the current change parameter includes an initial current value corresponding to the initial moment, a termination current value corresponding to the termination moment, and a change speed of the current value. The initial moment is the start moment of the maximum duration of light emission, the end moment is the end moment of the maximum duration of light emission, and the change speed of the current value is not always equal to zero.

Full brightness means the maximum brightness value, such as pure white, and full darkness represents the minimum brightness value, such as pure black. In the entire maximum lighting duration, the integral of the current value and time can represent the brightness value, specifically, the brightness value can be expressed by formula (2):

L＝∫∫(x×y)dxdy formula (2)

In the formula (2), L is the brightness value, x is the time, and y is the current value.

Combined with formula (2), it can be seen that the integral of the current value at each moment in the maximum luminous duration and the minimum luminous duration is the first preset brightness value, that is, the lowest gray scale, and the current at each moment in the maximum luminous duration The integral of the value and the maximum duration of light emission is the second preset brightness value, that is, the highest gray scale. Through the integral of the current current and time, and the ratio of the integral of the entire pattern, 256 or even higher gray scales can be achieved. express.

It should be noted that the change speed of the current value is not always equal to zero during the entire maximum luminescence duration, that is to say, the change speed of the current value can be locally zero, or be zero in stages, or not be zero, but cannot always be equal to zero.

Preferably, the change speed of the current value is a constant greater than zero, and at this time, the current in the maximum duration of light emission is a ramp current. As shown in Figure 3a, it is a schematic diagram of a ramp current provided by the embodiment of the present application, t ₀ , t ₁ , t ₂ , t ₃ , t ₄ , t ₅ and t ₆ are the target moments in the maximum duration of light emission, I ₀ , I ₁ , I ₂ , I ₃ , I ₄ , I ₅ and I ₆ are current values at the target time.

Using the above ramp current, the magnitude of the ramp current is proportional to the time, and the combination of the ramp current and time to represent the currently controlled brightness can better meet the requirements of higher gray levels.

Exemplarily, Fig. 3b exemplarily shows a schematic diagram of the change speed curves of various current values provided by the embodiment of the present application. As shown in Fig. 3b, redundant bits are used to realize different slopes and currents with slope changes over time The changing curves, the specific schematic diagrams are as follows A, B, C, and D are used to further distinguish and display different variants with lines of different thickness.

The purpose of the current change curve shown in Figure A is to prevent the LED from operating in the low current region. Based on the characteristics of the LED, using a current lower than the diode’s luminous threshold will cause the gamma correction curve to deviate from the expected, and the low current will cause the LED to emit color shift. affect the display effect. The use of low current regions can be avoided by setting the substrate current or widening the control range of the current.

The purpose of the current change curve shown in Figure B is to prevent the LED from working in the high current area. Since the human eye’s sensitivity to areas with high brightness decreases, exceeding a certain brightness does not contribute much to the expansion of the gray scale, and still consumes a large amount of current, making the display luminous efficiency If it becomes lower, the graph B can adjust the current change curve after exceeding a certain current threshold, so that the base is close to zero, and the luminous efficiency of the display can be improved without affecting the number of gray levels displayed.

The current change curves in Figure C and Figure D show that the curve presents a non-constant continuous change, the current change curve is nonlinear, and the slope of the curve can be switched between positive, zero and negative, which can achieve the effect of adjusting γ compensation and construct It is closer to the gamma compensation coefficient of the subjective perception of the human eye.

It should be noted that, the schematic diagrams of current variation with time in FIG. 3a and FIG. 3b are only used as examples, and do not constitute a limitation to the embodiment of the present application.

Step 204, according to the current change parameter, generate the current value corresponding to each moment in the maximum lighting duration.

Specifically, the current value corresponding to each moment in the maximum lighting duration can be generated in the following manner:

First, according to the maximum duration of light emission, the initial current value corresponding to the initial moment, the termination current value corresponding to the termination moment, and the change speed of the current value, a fitting curve of the current value changing with time is generated.

Then, the current value corresponding to each moment in the maximum luminescence duration is obtained from the fitting curve.

Step 205, according to the target luminance value of the target luminous pixel in the current frame and the current value corresponding to each moment in the maximum luminous duration, determine the off duration of the target luminous pixel in the current frame.

Specifically, after generating the current values corresponding to each moment in the maximum luminescence duration in the above-mentioned manner, the off-time duration of the target luminous pixel in the current frame is determined in the following manner:

In the first step, the fitting curve is integrated over the candidate time length to obtain the integration result. Wherein, the candidate duration is the time interval between any moment in the maximum luminescence duration and the starting point.

The second step is to obtain a target integration result whose value is equal to the target luminance value of the target luminous pixel in the current frame.

In the third step, the target candidate duration corresponding to the target integration result is determined as the turn-off duration of the target light-emitting pixel in the current frame.

Using the above method to determine the off-time of the target luminous pixel in the current frame can be combined with the current to control the brightness of the target luminous pixel, and the luminous control is more accurate. Theoretically, 6-bit current accuracy and 8-bit time accuracy can achieve 256 gray levels. show.

Step 206, time aligning the start time of the target light-emitting pixel to emit light with the start time of the maximum light-emitting duration.

Specifically, time alignment of the starting moment of the target light-emitting pixel emitting light with the starting moment of the maximum light-emitting duration can be performed in the following manner:

Get preset sync signal.

Align the start time of the target light-emitting pixel to emit light and the start time of the maximum light-emitting time with the start time of the synchronization signal respectively.

In other possible examples, those skilled in the art may also time-align the starting moment of the target luminous pixel's light emission with the starting moment of the maximum light emitting duration in other ways, for example, directly using the starting moment of the target luminous pixel's light emission as a reference , aligning the start time of the maximum light-emitting duration with the start time of light-emitting of the target light-emitting pixel, which is not specifically limited.

Step 207, generating a luminous current matching the current value corresponding to each moment in the maximum luminous duration, and sending it to the target luminous pixel, so that the target luminous pixel starts to emit light from the start time.

Step 208 , starting from the initial moment, turning off the luminous current after the off time period, so that the target luminous pixel stops emitting light.

Figure 4a exemplarily shows a schematic diagram of the light-emitting mode of the target light-emitting pixel provided by the embodiment of the present application. As shown in Figure 4a, while the single-line scanning signal scanning of the line where the target light-emitting pixel is located, the maximum light-emitting duration is intercepted from the single-line scanning duration , use the synchronous signal to time-align the start moment of the target light-emitting pixel with the start time of the maximum light-emitting time, and generate the preset light-emitting current, the target light-emitting pixel will be under the joint control of the light-emitting current and the off-time length, according to the preset Set the lighting mode to emit light.

In addition, within a single scanning duration, the embodiment of the present application can also simultaneously control multiple light-emitting pixels in the micro-display to emit light. FIG. As shown in Figure 4b, while the single-row scanning signal of the first row is scanning, the maximum duration of light emission is intercepted from the single-row scanning duration, and the starting moment of the first row and the first column of light-emitting pixels are illuminated by the synchronous signal, and the first row The starting moment of the light-emitting pixels in the second column is time-aligned with the starting point of the maximum light-emitting time, and after generating the preset light-emitting current, the light-emitting pixels in the first row and the first column are aligned with the light-emitting pixels in the first row and the second column. The pixels emit light in a preset light-emitting manner under the common control of the same light-emitting current and their respective off-times. While the single-row scanning signal of the second row is scanning, the maximum duration of light emission is intercepted from the single-row scanning duration, and the starting moment of the light-emitting pixels in the first column of the second row and the second row of second row are illuminated by using the synchronization signal The starting moment of the pixel's light emission is time-aligned with the starting moment of the maximum light-emitting duration, and after generating the preset light-emitting current, the light-emitting pixels in the first column of the second row and the light-emitting pixels in the second column of the second row are respectively in the same Under the common control of the light-emitting current and the respective off-time lengths, light is emitted according to a preset light-emitting manner.

That is to say, the light emission control method provided by the embodiment of the present application can simultaneously control all the light emitting pixels in the micro-display to emit light. During the first scanning period, the first row of light emitting pixels emit light; The light-emitting pixels in the second row emit light, and so on, wherein the light-emitting pixels in each row share the same ramp current whose changing speed is a constant greater than zero.

In addition, the light emission control method provided in the embodiment of the present application can provide different ramp currents for each row of light emitting pixels when simultaneously controlling all the light emitting pixels in the micro display screen to emit light.

Preferably, a ramp current with opposite changing speeds of currents in odd and even rows may be used.

Exemplarily, in the first scanning period, the first row of light-emitting pixels emits light under the control of a ramp current whose changing speed is a constant greater than zero, and in the second scanning time, the second row of light-emitting pixels emit light at Light is emitted under the control of a constant ramp current that is less than zero, and within the third scanning period, the third row of light-emitting pixels emits light under the control of a ramp current whose change rate is a constant greater than zero, and so on, and so on ,No longer.

By adopting the method that the ramp currents of the odd rows and the even rows change at opposite speeds, the problem of voltage fluctuation and noise caused by the ramp currents in the same direction for the entire LED array can be avoided, which is beneficial to the uniformity and stability of the brightness of the LED display array.

In this way, the embodiment of the present application discloses an LED-based micro-display light emission control method, according to the micro-display's own attributes and the data bit width of each light-emitting pixel's candidate brightness value in each frame, determine the brightness of each light-emitting pixel After the maximum light-emitting time and the minimum light-emitting time, the current change parameter is determined by combining the first preset brightness value corresponding to full darkness and the second preset brightness value corresponding to full brightness, wherein the change speed of the current value is not always equal to zero, according to The current change parameter generates the current value corresponding to each moment in the maximum light-emitting time, and then combines the target brightness value of each light-emitting pixel in the current frame to determine the off-time of the light-emitting pixel in the current frame, and the starting time of each light-emitting pixel to emit light Time-align with the starting point of the maximum light-emitting duration, and generate a light-emitting current that matches the current value corresponding to each moment in the maximum light-emitting time, so that the light-emitting pixels start to emit light from the initial moment, and turn off the light-emitting current after the turn-off time , so that the emitting pixel stops emitting light. The whole method precisely controls the actual brightness of the light-emitting pixels by combining the current value and the light-emitting time, so that the difference between the actual brightness of the light-emitting pixels can be recognized by the human eye in time, with high precision and relatively simple hardware implementation. It satisfies the requirement of higher number of gray scales well.

The following are system embodiments of the present application, which can be used to implement the method embodiments of the present application. For details not disclosed in the system embodiments of the present application, please refer to the method embodiments of the present application.

FIG. 5 exemplarily shows a schematic diagram of the overall structure of an LED-based micro-display lighting control system provided by an embodiment of the present application. As shown in Figure 5, the system has the function of realizing the above-mentioned lighting control method, and is used to control the lighting mode of any light-emitting pixel in the LED-based micro-display screen. The function can be realized by hardware, or the corresponding Software Implementation. The system may include: a gray scale modulation circuit 501 , a current control circuit 502 , a time control circuit 503 , a line scanning synchronization circuit 504 , a controlled current source 505 and a control switch 506 .

The gray-scale modulation circuit 501 is connected with the current control circuit 502, the time control circuit 503 and the line scanning synchronous circuit 504 respectively, and the line scanning synchronous circuit 504 is also connected with the current control circuit 502 and the time control circuit 503 respectively, and the current control circuit 502 is connected with the controlled The current source 505 is connected, and the control switch 506 is respectively connected with the controlled current source 505, the target light-emitting pixel A and the time control circuit 503, and the target light-emitting pixel A is any light-emitting pixel in the micro-display.

The grayscale modulation circuit 501 is used to determine the maximum light-emitting duration of the target light-emitting pixel according to the playing frame rate of the micro display screen and the number of rows of the light-emitting pixel array. And, according to the data bit width of the candidate luminance value of each luminous pixel in each frame in the micro-display screen, and the maximum luminous duration, determine the minimum luminous duration of the target luminous pixel. And, according to the first preset brightness value corresponding to full darkness, the second preset brightness value corresponding to full brightness, the maximum duration of light emission and the minimum duration of light emission, determine the current change parameter, the current change parameter includes the initial current value corresponding to the initial moment, The end current value and the change speed of the current value corresponding to the end time, the initial time is the start time of the maximum light emitting time, and the end time is the end time of the maximum light emitting time.

The current control circuit 502 is configured to generate a current value corresponding to each moment in the maximum light emitting duration according to the current change parameter. Specifically, the current control circuit 502 may use a DAC current source or an analog ramp current generator.

The grayscale modulation circuit 501 is further configured to determine the off-time of the target light-emitting pixel in the current frame according to the target brightness value of the target light-emitting pixel in the current frame and the current value corresponding to each moment in the maximum light-emitting duration.

The row scanning synchronous circuit 504 is used for time-aligning the start time of the target light-emitting pixel to emit light with the start time of the maximum light-emitting duration.

The controlled current source 505 is used to generate a light-emitting current that matches the current value corresponding to each moment in the maximum light-emitting duration, and send it to the target light-emitting pixel, so that the target light-emitting pixel starts to emit light from the start moment.

The time control circuit 503 is used to control the control switch 506 to cut off the luminous current after the off period from the initial moment, so that the target luminous pixel stops emitting light. Specifically, the time control circuit 503 may use a timer.

Specifically, when using the light emission control system provided by the embodiment of the present application to simultaneously control all the light emitting pixels in the micro-display to emit light, and all the light emitting pixels share the same ramp current, the structure shown in Figure 6a can be adopted, and Figure 6a shows an example A specific structural schematic diagram of a light-emitting control system based on an LED-based micro-display provided in the embodiment of the present application is shown. n light-emitting pixels) share the gray-scale modulation circuit 501, the current control circuit 502, the time control circuit 503 and the row scanning synchronization circuit 504, and each light-emitting pixel is connected with a corresponding controlled current source 505 and a control switch 506, each The controlled current source 505 and the control switch 506 corresponding to the light-emitting pixels are both connected to the current control circuit 502 and the time control circuit 503 .

When using the light emission control system provided by the embodiment of the present application, all light emitting pixels in the micro display screen are simultaneously controlled to emit light, and the light emitting pixels in odd rows share the same first ramp current, and the light emitting pixels in even row share the slope of the first ramp current In the case of the opposite second slope current, the structure shown in Figure 6b can be adopted, and Figure 6b exemplarily shows another specific structural diagram of a lighting control system based on an LED-based micro-display provided in an embodiment of the present application , all light-emitting pixels share the gray-scale modulation circuit 501, all the light-emitting pixels of odd rows (such as A11, A12, ..., A1n) are commonly connected with a set of current control circuit 502, time control circuit 503 and row scanning synchronization circuit 504, all even The light-emitting pixels of the row (such as A21, A22, ..., A2n) are commonly connected with a set of current control circuit 502, time control circuit 503 and row scanning synchronization circuit 504, no matter it is an odd row or an even row, all the light-emitting pixels are connected with The corresponding controlled current source 505 and control switch 506 are connected to the current control circuit 502 and time control circuit 503 corresponding to the row where the pixel is located.

In a practicable manner, the current control circuit 502 includes:

The fitting curve generation module is used to generate a fitting curve of the current value changing with time according to the maximum duration of light emission, the initial current value corresponding to the initial moment, the termination current value corresponding to the termination moment, and the change speed of the current value.

The current value obtaining module is used to obtain the current value corresponding to each moment in the maximum luminescence duration from the fitting curve.

In an implementable manner, the grayscale modulation circuit 501 includes:

The integration result acquisition module is used to integrate the fitting curve over the candidate time length to obtain the integration result. The candidate time length is the time interval between any moment in the maximum luminescence duration and the starting point.

The target integration result acquisition module is configured to acquire a target integration result whose value is equal to the target luminance value of the target luminescent pixel in the current frame.

The off-time length determination module is used to determine the target candidate time length corresponding to the target integration result as the off-time length of the target light-emitting pixel in the current frame.

In a practicable manner, the grayscale modulation circuit includes:

The playback duration determining module is used to determine the playback duration of a single frame according to the playback frame rate of the micro-display.

The single-row scanning duration determining module is used to determine the single-row scanning duration of each row of luminous pixels according to the row number of the luminous pixel array and the playback duration of a single frame.

The maximum lighting duration determination module is configured to intercept any target duration from the single-line scanning duration, and determine the target duration as the maximum lighting duration of the target luminous pixel.

In an implementable manner, the row scan synchronization circuit 504 includes:

The synchronous signal obtaining module is used to obtain a preset synchronous signal.

The alignment module is configured to align the start moment of the target light-emitting pixel to emit light and the start moment of the maximum duration of light emission with the start moment of the synchronization signal respectively.

In this way, the embodiment of the present application discloses an LED-based micro-display light emission control system. According to the self-properties of the micro-display and the data bit width of the candidate brightness value of each light-emitting pixel in each frame, determine the brightness of each light-emitting pixel. After the maximum light-emitting time and the minimum light-emitting time, the current change parameter is determined by combining the first preset brightness value corresponding to full darkness and the second preset brightness value corresponding to full brightness, wherein the change speed of the current value is not always equal to zero, according to The current change parameter generates the current value corresponding to each moment in the maximum light-emitting time, and then combines the target brightness value of each light-emitting pixel in the current frame to determine the off-time of the light-emitting pixel in the current frame, and the starting time of each light-emitting pixel to emit light Time-align with the starting point of the maximum light-emitting duration, and generate a light-emitting current that matches the current value corresponding to each moment in the maximum light-emitting time, so that the light-emitting pixels start to emit light from the initial moment, and turn off the light-emitting current after the turn-off time , so that the light-emitting pixel stops emitting light. The whole system precisely controls the actual brightness of the light-emitting pixels through the combination of current value and light-emitting time, so that the difference between the actual brightness of the light-emitting pixels can be recognized by the human eye in time, with high precision and simple hardware implementation, which can be compared It satisfies the requirement of higher number of gray scales well.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although the specification is described according to the embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (10)

1. A kind of luminescence control method based on LED miniature display screen, described luminescence control method is used for controlling the luminescence mode of any light-emitting pixel in the microdisplay screen based on LED, it is characterized in that, comprises:

   Determine the maximum light-emitting duration of the target light-emitting pixel according to the play frame rate of the micro-display screen and the number of rows of the light-emitting pixel array, and the target light-emitting pixel is any light-emitting pixel in the micro-display screen;

   According to the data bit width of the candidate luminance value of each luminous pixel in each frame in the micro-display screen, and the maximum luminous duration, determine the minimum luminous duration of the target luminous pixel;

   According to the first preset brightness value corresponding to full darkness, the second preset brightness value corresponding to full brightness, the maximum lighting duration and the minimum lighting duration, the current change parameter is determined, and the current variation parameter includes the current change parameter corresponding to the initial moment. The initial current value, the termination current value corresponding to the termination moment, and the change speed of the current value, the initial moment is the start moment of the maximum lighting duration, the termination moment is the end moment of the maximum lighting duration, and the current value The rate of change of is not always equal to zero;

   Generate current values corresponding to each moment in the maximum lighting duration according to the current change parameter;

   According to the target luminance value of the target luminous pixel in the current frame and the current value corresponding to each moment in the maximum luminous duration, determine the off duration of the target luminous pixel in the current frame;

   time aligning the start moment of the target light-emitting pixel to emit light with the start moment of the maximum light-emitting duration;

   Generate a luminous current that matches the current value corresponding to each moment in the maximum luminous duration, and send it to the target luminous pixel, so that the target luminous pixel starts to emit light from the starting moment;

   Starting from the starting moment, the light-emitting current is turned off after the off-time period, so that the target light-emitting pixel stops emitting light.
2. The lighting control method according to claim 1, wherein the generating the current value corresponding to each moment in the maximum lighting duration according to the current change parameter includes:

   Generate a fitting curve of the current value changing with time according to the maximum duration of light emission, the initial current value corresponding to the initial moment, the termination current value corresponding to the termination moment, and the change speed of the current value;

   The current value corresponding to each moment in the maximum lighting duration is obtained from the fitting curve.
3. The light emission control method according to claim 2, wherein, according to the target brightness value of the target light emitting pixel in the current frame and the current value corresponding to each moment in the maximum light emitting duration, it is determined that the target light emitting pixel is at The shutdown duration of the current frame, including:

   Integrating the fitting curve over the candidate time length to obtain an integration result, the candidate time length is the time interval between any moment in the maximum luminous time length and the starting point moment;

   Acquiring a target integration result whose value is equal to the target luminance value of the target luminescent pixel in the current frame;

   The target candidate duration corresponding to the target integration result is determined as the off duration of the target luminous pixel in the current frame.
4. The light emission control method according to claim 1, wherein the determination of the maximum light emission duration of the target light emitting pixel according to the play frame rate of the micro display screen and the number of rows of the light emitting pixel array includes:

   Determine the playing time of a single frame according to the playing frame rate of the miniature display screen;

   According to the number of rows of the luminous pixel array and the playback duration of the single frame, determine the single row scanning duration of each row of luminous pixels;

   Any target duration is intercepted from the single-row scanning duration, and the target duration is determined as the maximum light-emitting duration of the target light-emitting pixel.
5. The light emission control method according to claim 1, wherein the time alignment of the start moment of the target light emitting pixel to emit light with the start moment of the maximum light emission duration comprises:

   Obtain a preset sync signal;

   Aligning the start time of the target light-emitting pixel to emit light and the start time of the maximum light-emitting duration with the start time of the synchronization signal respectively.
6. A light emitting control system based on an LED-based micro-display, the light-emitting control system is used to control the light-emitting mode of any light-emitting pixel in the LED-based micro-display, it is characterized in that it includes a gray scale modulation circuit, a current control circuit, Time control circuit, line scanning synchronization circuit, controlled current source and control switch;

   The gray scale modulation circuit is respectively connected to the current control circuit, the time control circuit and the row scanning synchronization circuit, and the row scanning synchronization circuit is also connected to the current control circuit and the time control circuit respectively, The current control circuit is connected to the controlled current source, and the control switch is respectively connected to the controlled current source, the target luminous pixel and the time control circuit, and the target luminous pixel is the Any light-emitting pixel;

   The gray-scale modulation circuit is used to determine the maximum duration of light emission of the target light-emitting pixel according to the playback frame rate of the micro-display screen and the number of rows of the light-emitting pixel array; The data bit width of the candidate brightness value of each frame, and the maximum duration of light emission, determine the minimum duration of light emission of the target light-emitting pixel; and, according to the first preset brightness value corresponding to full darkness and the second preset brightness corresponding to full brightness Value, the maximum light-emitting time length and the light-emitting minimum time length, determine the current change parameters, the current change parameters include the initial current value corresponding to the initial moment, the termination current value corresponding to the termination time, and the change speed of the current value, the initial The moment is the start moment of the maximum duration of light emission, and the end moment is the end moment of the maximum duration of light emission;

   The current control circuit is configured to generate a current value corresponding to each moment in the maximum lighting duration according to the current change parameter;

   The gray-scale modulation circuit is further configured to determine whether to turn off the target luminous pixel in the current frame according to the target luminance value of the target luminous pixel in the current frame and the current value corresponding to each moment in the maximum light-emitting duration. duration;

   The row scanning synchronization circuit is used to time-align the starting moment of the target light-emitting pixel to emit light with the starting moment of the maximum light-emitting duration;

   The controlled current source is used to generate a light-emitting current that matches the current value corresponding to each moment in the maximum light-emitting duration, and send it to the target light-emitting pixel, so that the target light-emitting pixel starts from the start start to shine all the time;

   The time control circuit is configured to control the control switch to turn off the luminescence current after the off period from the start moment, so that the target luminescence pixel stops emitting light.
7. The lighting control system according to claim 6, wherein the current control circuit comprises:

   A fitting curve generating module, configured to generate a curve of the current value changing over time according to the maximum lighting duration, the initial current value corresponding to the initial moment, the termination current value corresponding to the termination moment, and the change speed of the current value. Curve fitting;

   The current value acquisition module is configured to acquire the current value corresponding to each moment in the maximum lighting duration from the fitting curve.
8. The lighting control system according to claim 7, wherein the gray scale modulation circuit comprises:

   An integration result acquisition module, configured to integrate the fitting curve over a candidate time length to obtain an integration result, the candidate time length being the time interval between any moment in the maximum light-emitting time and the starting point;

   A target integration result acquisition module, configured to acquire a target integration result whose value is equal to the target luminance value of the target luminescent pixel in the current frame;

   The off-duration determining module is configured to determine the target candidate duration corresponding to the target integration result as the off-duration of the target luminescent pixel in the current frame.
9. The lighting control system according to claim 6, wherein the gray scale modulation circuit comprises:

   The playback duration determination module is used to determine the playback duration of a single frame according to the playback frame rate of the micro display screen;

   A single-row scanning duration determining module, configured to determine the single-row scanning duration of each row of luminous pixels according to the number of rows of the luminous pixel array and the playback duration of the single frame;

   The maximum luminescence duration determining module is configured to intercept any target duration from the single-row scanning duration, and determine the target duration as the maximum luminescence duration of the target luminous pixel.
10. The lighting control system according to claim 6, characterized in that, the row scanning synchronization circuit comprises:

    A synchronous signal acquisition module, configured to acquire a preset synchronous signal;

    The alignment module is configured to align the starting moment of the target light-emitting pixel to emit light and the starting moment of the maximum light-emitting duration with the starting moment of the synchronization signal respectively.

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