Display driving method, readable storage medium and scanning display device

Abstract

The application discloses a display driving method, a readable storage medium and a scanning display device. The method is applied to the scanning display device and comprises the following steps: obtaining effective scanning time and invalid scanning time of a scanning display device; selecting a performance mode to drive the light source in the effective scanning time; setting an initial current of the light source according to pixel information to be displayed of the scanning display device in the performance mode; selecting an energy-saving mode to drive the light source in the invalid scanning time; and setting the initial current of the light source to a preset value in the energy-saving mode. Since the initial current of the light source is different in different time periods, the technical problem that the driving current of the LD is always above the threshold current, which leads to the standby power consumption of the LD being always maintained and the energy utilization rate being low, can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of projection display, in particular to a display driving method, readable storage medium and scanning display device. BACKGROUND

[0002] The imaging principle of fiber scanning display technology (FSD) is that a fiber scanning display device drives a fiber to move along a predetermined two-dimensional scanning trajectory, modulates light corresponding to each pixel point of a to-be-displayed image output by a light source, and then projects the light corresponding to each pixel point of the to-be-displayed image onto a projection surface one by one to form a projection image.

[0003] In combination with the above fiber scanning display technology and LD (Laser Diode, semiconductor laser) internal modulation laser display technology, it is considered to be an ideal optical display scheme on an AR (Augmented Reality, augmented reality) device. During the display process, the LD needs to be completely turned off (no light output) at the pixel level and then turned on to a certain target brightness instantaneously, which requires a high response speed of the LD.

[0004] Considering the actual display frame rate, specification requirements, and the principle of fiber scanning display technology, the fiber scanning display technology has extremely high response requirements for the LD, which needs to make the light energy output of the LD reach the target value to be displayed from 0 instantaneously within a time range of ns or even sub-ns. Moreover, the light-emitting principle of the LD determines that the response time of the LD is limited by the material and device characteristics.

[0005] In order to reduce the response time of the LD during fast modulation, the conventional method is to always make the driving current of the LD above the threshold value. However, this method causes the standby power consumption of the LD to always remain, and the energy utilization rate is low. SUMMARY

[0006] The purpose of the present application is to provide a display driving method, readable storage medium and scanning display device, which can alleviate the technical problem that the driving current of the LD is always above the threshold current, which causes the standby power consumption of the LD to always remain and the energy utilization rate is low in the prior art.

[0007] In order to achieve the above-mentioned application purpose, the first aspect of the embodiment of the present application provides a display driving method applied to a scanning display device, wherein the scanning display device comprises a light source and a scanning display device, and the scanning display device is used for scanning and emitting light emitted by the light source, and the method comprises the following steps:

[0008] acquiring effective scanning time and invalid scanning time of the scanning display device;

[0009] In the effective scanning time, a performance mode is selected to drive the light source; in the performance mode, the initial current of the light source is set according to pixel information to be displayed by the scanning display device;

[0010] In the invalid scanning time, a power saving mode is selected to drive the light source; in the power saving mode, the initial current of the light source is set as a preset value.

[0011] Optionally, the light source is a laser, the initial current of the light source in the performance mode varies in a preset current interval, the minimum value of the preset current interval is 0, and the maximum value of the preset current interval is a threshold current of the laser for generating laser; and the preset value of the initial current of the light source in the power saving mode is 0.

[0012] Optionally, in the performance mode, the initial current of the light source is set according to the pixel information to be displayed by the scanning display device, including:

[0013] In the performance mode, the pixel information to be displayed by the scanning display device is acquired; the pixel information to be displayed includes pre-cached continuous pixel information.

[0014] When the gray scale information of a color channel corresponding to a plurality of continuous pixel information is 0, the initial current of the light source corresponding to the color channel is turned off; when the gray scale information of the color channel corresponding to the pixel information is not 0, the initial current of the light source corresponding to the color channel is turned on.

[0015] Optionally, when the gray scale information of the color channel corresponding to the pixel information is not 0, the initial current of the light source corresponding to the color channel is turned on, including:

[0016] When the gray scale information of the color channel corresponding to the pixel information is not 0, the initial current of the light source corresponding to the color channel is turned on at least one pixel time in advance.

[0017] Optionally, the continuous pixel information includes one row of pixel information, a plurality of rows of pixel information or one frame of pixel information.

[0018] Optionally, the effective scanning time refers to a time during which a scanning track of the scanning display device is used to display an image; and the invalid scanning time refers to a time during which the scanning track of the scanning display device is not used to display the image.

[0019] Optionally, when a scanning mode of the scanning display device is a grid format scanning, the invalid scanning time includes a plurality of fast axis scanning periods.

[0020] A second aspect of the embodiment of the application provides a non-temporary computer readable storage medium, which stores a computer program, and the program is executed by a processor to implement steps of the method according to the first aspect.

[0021] The third aspect of the embodiment of the present application provides a scanning display device, comprising:

[0022] a memory, in which a computer program is stored;

[0023] a processor, configured to execute the computer program in the memory to implement the steps of the method according to the first aspect.

[0024] The one or more technical solutions in the embodiment of the present application have at least the following technical effects or advantages:

[0025] In the solution of the embodiment of the present application, during the operation of the AR device, the effective scanning time and the invalid scanning time of the scanning display device are acquired; in the effective scanning time, the performance mode is selected to drive the light source; in the performance mode, the initial current of the light source is set according to the pixel information to be displayed by the scanning display device; in the invalid scanning time, the power saving mode is selected to drive the light source; in the power saving mode, the initial current of the light source is set as a preset value. According to the effective scanning time and the invalid scanning time of the scanning display device, the initial current of the light source is different in different time periods, which can alleviate the technical problem that in the prior art, the driving current of the LD is always above the threshold current, which can cause the standby power consumption of the LD to be always maintained and the energy utilization rate to be low, and can achieve the technical effect of reducing the standby power consumption of the LD. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings:

[0027] Figure 1 A scanning track schematic diagram of the grid format scanning mode provided by the embodiment of the present application;

[0028] Figure 2 A flowchart schematic diagram of the display driving method provided by the embodiment of the present application;

[0029] Figures 3A-3C A schematic diagram of the invalid scanning time and the effective scanning time provided by the embodiment of the present application;

[0030] Figure 4 A block diagram of the scanning display device provided by the embodiment of the present application. DETAILED DESCRIPTION

[0031] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0032] In the embodiments of the present application, first, two driving modes of the LD are described.

[0033] Threshold current I of the LD th refers to the critical current of the laser to generate laser, and when the current is higher than I th , the LD starts to emit laser; and when the current is lower than I th , the LD spontaneously radiates and cannot form controlled, high-energy density, and good monochromaticity light. Below the threshold I th , the response time of the LD is relatively long, which can reach tens of ns. Therefore, when the LD is internally modulated, the current provided by the LD driving current is usually composed of two parts I1=I th +I b , wherein I th is a direct current component (unchanged), I b is a bias current (a variable modulation current), and the change of I b signal enables the LD to quickly respond to achieve stable light energy output, which is referred to as the I1 driving mode in the present application. Another driving mode is the I2 driving mode, I2=I b , that is, without a direct current component, and the problem brought thereby is that the response time of the LD is increased.

[0034] Based on the information of the above I1 driving mode and the I2 driving mode, when the LD adopts the I2 driving mode, if the color corresponding to the display picture or pixel information is 0, the driving current of the LD corresponding to the color is 0, and the electric power consumption corresponding thereto is P=0. When the LD adopts the I1 driving mode, if the color corresponding to the display picture or pixel information is 0, the driving current corresponding to the color is I th , and the electric power consumption thereof is P=U*I th , U is voltage, and P2 is standby power of the LD, that is, a fixed value that always exists regardless of the display content as long as the machine is turned on. The color can be R (red), G (green), and B (blue) three color channels.

[0035] In the embodiments of the present application, the optical fiber scanning display device is taken as an example to describe the scanning mode, which is a grid scanning mode, as shown in Figure 1 Figure 1 ​The schematic diagram of the grid scanning optical fiber track provided by the embodiment of the present application is shown in the figure, and the grid in the background is a virtual pixel grid artificially divided. For the scanner in the grid scanning mode, two actuating parts are included to provide fast axis direction (horizontal direction) driving and slow axis direction (vertical direction) driving respectively. Generally, the slow axis direction driving frequency is less than the fast axis direction driving frequency. The optical fiber is scanned according to the grid track under the synergistic action of the vibrations generated by the two actuating parts.

[0036] Due to the comprehensive factors such as the nonlinear control of the optical fiber scanning track, the display time specificity, the energy uniformity correction requirement, the circuit chip processing requirement, the cost control and the like, only a part of the actual scanning track is used for displaying information, and the rest of the track is not used. The effective scanning utilization rate of the optical fiber scanning display technology can be defined as the ratio of the track time used for information display to the track repetition period of mechanical scanning when a white picture is displayed. Assuming that the ratio is r, then the proportion of 1-r is the invalid scanning time (for information display). In other words, the effective scanning time refers to the time when the scanning track of the scanning display device is used for displaying an image, and the invalid scanning time refers to the time when the scanning track of the scanning display device is not used for displaying an image.

[0037] In the invalid scanning time, if I th exists, it will always contribute to part of the power consumption P1. In the effective scanning time, the black picture (for a certain color channel, the gray scale information of the color channel is 0) in the picture display will also contribute to the power consumption P2. At this time, the standby power consumption is composed of two parts P0=P1+P2.

[0038] Based on the above analysis, the embodiment of the present application provides a display driving method for reducing power consumption, as shown in Figure 2 . Figure 2 The flowchart of the display driving method provided by the embodiment of the present application is shown in the figure, and the method includes the following steps.

[0039] Step 201, obtaining the effective scanning time and the invalid scanning time of the scanning display device.

[0040] Step 202, in the effective scanning time, selecting a performance mode to drive the light source; in the performance mode, setting the initial current of the light source according to the pixel information to be displayed by the scanning display device.

[0041] Step 203, in the invalid scanning time, selecting a power saving mode to drive the light source; in the power saving mode, setting the initial current of the light source to a preset value.

[0042] The initial current of the light source in different time periods is different, which can alleviate the technical problem that the driving current of the LD is always above the threshold current in the prior art, which causes the LD standby power consumption to always remain and the energy utilization rate to be low, and can achieve the technical effect of reducing the LD standby power consumption.

[0043] In the embodiment of the present application, the initial current of the light source in the performance mode varies in a preset current interval, the preset current interval is [0, I th ], the minimum value of the preset current interval is 0, and the maximum value is the threshold current I th of the laser to generate laser. In other words, in the performance mode, the pixel information to be displayed is dynamically adjusted to adjust the driving mode of each laser and the corresponding initial current of the light source, so that the initial current of the light source varies in the preset current interval. In the power saving mode, the light source is driven according to the I2 driving mode, and the preset value of the initial current of the light source is 0.

[0044] Specifically, in the invalid scanning time, the threshold current I th is selected to be turned off, the I2 driving mode is maintained to reduce power consumption, and according to the characteristics of the scanning track of the grid format scanning mode, the invalid scanning time is usually several fast-axis scanning periods (long time), so the corresponding driving configuration conversion is easy to realize on the circuit. When the optical fiber scanning enters the effective scanning time area from the invalid scanning time area, the threshold current I th is turned on, the I1 driving mode is maintained, and thus the P1 part power consumption can be eliminated. In the embodiment of the present application, when the optical fiber scanning enters the effective scanning time, the initial current of the light source can be turned on at least one pixel time in advance, so as to ensure the response speed of the light source.

[0045] For normal display content, each pixel belongs to unpredictable information. Therefore, in the effective scanning time, the display information of the scanning display device to be displayed (such as pre-caching a row, several rows, or even a frame of display content) is obtained, and then according to the continuous pixel information content, for the black screen in the picture display, the threshold current I th is turned off, and when the display information needs to be output, the threshold current I th is selectively turned on in advance, which can not only achieve the purpose of reducing P2, but also ensure the response speed of the LD, that is, in this mode, the actual driving current I1 is composed of two parts, the variable I th1 and I b .

[0046] For example, the pixel information gray scale is 0-0-0-200-50-0-80-120-160-180, and the corresponding threshold is 5-5-5-5-5-5-5-5-5-5 according to the conventional I1 driving mode, and the bias currents ib are 0-0-0-20-5-0-8-12-16-18 respectively, while the optimized driving mode can be I th 0-0-5-5-5-5-5-5-5-5, the bias currents ib are 0-0-0-20-5-0-8-12-16-18 respectively, while the optimized driving mode can be I b 0-0-5-5-5-5-5-5-5-5, the bias currents ib are 0-0-0-20-5-0-8-12-16-18 respectively, while the optimized driving mode can be I th +I b 0-0-5-5-5-3-3-3-4-5, I th 0-0-5-5-5-3-3-3-4-5, I b 0-0-0-20-5-0-10-14-17-18.

[0047] It can be seen that, in the scheme of the embodiment of the application, the power consumption can be optimized according to different display information, so that P2 is reduced, and the above examples are only illustrative. Since the opening current I th of the LD output laser is related to the threshold current I th , when the driving current is located below I th , the farther the distance is, the longer the required lighting time is, and the closer the distance is, the shorter the required time is, so the above scheme is feasible in optimizing the power consumption.

[0048] Next, the invalid scanning time and the effective scanning time in the embodiment of the application are described.

[0049] In the imaging mode based on mechanical scanning, the scanning track path is mechanically continuous, and generally presents a track form of a trigonometric function. Taking a grid format scanning as an example, in order to ensure normal image display, it is required that the track intervals are uniform in the slow axis (low frequency) direction, that is, the speed of the slow axis track is nearly constant through track control means, and from the control difficulty, it is difficult to realize perfect straight-line turning at the edge of the slow axis track, that is, the track control precision at the edge position is poor, and it is not suitable for imaging, and the scanning track of this part of time is defined as invalid track, and the corresponding time is invalid scanning time.

[0050] Similarly, the slow axis is controlled to be a sawtooth wave or quasi-sawtooth wave trajectory, and after the slow axis reaches the edge, it will quickly sweep back in a very short time, and due to the continuity problem of the mechanical scanning trajectory, this part of the sweep will definitely occupy a certain time, and is not suitable for imaging, and also belongs to invalid scanning time; in addition, the fast axis high-frequency scanning trajectory can be represented by a trigonometric function, in order to make the pixels uniform, a variable modulation signal is needed to excite the LD to emit light, and due to the infinite difference between the boundary and the middle speed, the hardware implementation difficulty and cost increase dramatically, therefore, the fast axis edge part of the trajectory is not used for imaging, and this part also belongs to invalid scanning trajectory.

[0051] The Lissajous scanning form is also similar, in general, the trajectory part not used for information display, i.e. defined as invalid scanning trajectory, the corresponding time is invalid scanning time.

[0052] The above-mentioned example of the grid format scanning is shown in FIG. 1, which is a two-dimensional scanning trajectory of an optical fiber, the horizontal axis is the time measured in one period of the fast axis, the half-period time length of the fast axis corresponds to the time from the leftmost end of the trajectory to the adjacent rightmost end, i.e. t1, t4, due to the change of the speed according to the trigonometric function, considering the actual hardware driving limitation, the edge is not used for imaging, i.e. t2-t1, t4-t3, which is invalid scanning time, and t3-t2 is valid scanning time. Figure 3A As shown in FIG. 2, which is a slow axis trajectory of an optical fiber, it is an isosceles triangle mode, the horizontal axis is the time corresponding to the slow axis, from t6-t1 corresponding to one slow axis period, due to the difficulty of trajectory control and the actual response characteristics of the scanning display device, the speed changes obviously at the corner and cannot be used for imaging, which also belongs to invalid scanning trajectory, specifically t2-t1, t4-t3, t6-t5.

[0053] Figure 3B As shown in FIG. 3, which is another form of scanning trajectory, quasi-sawtooth wave, the horizontal axis corresponds to time, and the figure draws the actual motion trajectory of the slow axis of the optical fiber, t3-t1 corresponds to one slow axis period, similarly, due to the difficulty of control and the actual response characteristics of the scanning display device, the time period of the speed change is not used for imaging belongs to invalid scanning time, specifically t2-t1.

[0054] In the embodiment of the present application, the laser includes R, G and B three-color lasers, and in the AR display, the entire display area does not always maintain all three colors with non-zero grayscale information at the same time, therefore, the laser of each color can be controlled independently, the driving mode of each laser is flexibly and dynamically adjusted, the quality of image display is ensured, and the standby power consumption of the light source is compressed to the lowest, thereby improving the energy utilization rate. Figure 3C

[0055] In the embodiment of the present application, the laser includes R, G and B three-color lasers, and in the AR display, the entire display area does not always maintain all three colors with non-zero grayscale information at the same time, therefore, the laser of each color can be controlled independently, the driving mode of each laser is flexibly and dynamically adjusted, the quality of image display is ensured, and the standby power consumption of the light source is compressed to the lowest, thereby improving the energy utilization rate.

[0056] ​​It should be noted that the scheme in the embodiment of the present application is not only applicable to the optical fiber scanning, but also applicable to a laser scanning imaging system such as MEMS (English full name: Microelectro Mechanical Systems, Chinese name: Microelectro Mechanical Systems).

[0057] Based on the same inventive concept, the embodiment of the present application further provides a projection display device 400, as shown in the figure, comprising a light source 401, the light source 401 is used for outputting image light; a scanning display device 402 connected with the light source 401, the light emitted by the light source 401 is coupled into the scanning display device 402, and the light is emitted through the scanning display device 402, a memory 403, the memory 403 stores a computer program; a processor 404, used for executing the computer program in the memory 403, so as to realize the display driving method and control the light source 401 to emit light. Figure 4

[0058] The embodiment of the present application further provides a computer readable storage medium comprising program instructions, the program instructions are executed by the processor to realize the steps of the display driving method. For example, the computer readable storage medium can be a memory, and the program instructions can be executed by the processor of the projection display device to complete the display driving method.

[0059] The embodiment of the present application further provides a computer program product, the computer program product contains a computer program capable of being executed by a programmable device, the computer program has a code part for executing the display driving method when executed by the programmable device.

[0060] All features disclosed in this specification, or all steps of any methods or processes disclosed, can be combined in any combination, except combinations where at least some features and / or steps are mutually exclusive.

[0061] Any feature disclosed in this specification, unless stated otherwise, can be replaced by any equivalent or similar feature, or any other feature that serves the same, similar or equivalent function. In other words, except where expressly stated to the contrary, alternative or equivalent features are considered to be part of the disclosure and are within the scope of the present application.

[0062] The present application is not limited to the foregoing specific embodiments. The present application extends to any novel one, or any novel combination, of the features disclosed in this specification, and to any novel method or process disclosed, or any novel step thereof, or any novel combination of steps.​

Claims

1. A display driving method applied to a scanning display device, characterized by, The scanning display device comprises a light source and a scanning display device for scanning the light emitted by the light source to be emitted; the method comprises: acquiring effective scanning time and invalid scanning time of the scanning display device; in the effective scanning time, a performance mode is selected to drive the light source; in the performance mode, pixel information to be displayed by the scanning display device is acquired; the pixel information to be displayed comprises continuous pixel information pre-cached; when the gray scale information of a color channel corresponding to a plurality of continuous pixel information is 0, the initial current of the light source corresponding to the color channel is turned off; when the gray scale information of a color channel corresponding to pixel information is not 0, the initial current of the light source corresponding to the color channel is turned on; in the invalid scanning time, a power saving mode is selected to drive the light source; in the power saving mode, the initial current of the light source is set to a preset value.

2. The method of claim 1, wherein, The light source is a laser, the initial current of the light source in the performance mode varies in a preset current interval, the minimum value of the preset current interval is 0, and the maximum value of the preset current interval is the threshold current of the laser to generate laser; the preset value of the initial current of the light source in the power saving mode is 0.

3. The method of claim 1, wherein, When the gray scale information of a color channel corresponding to pixel information is not 0, the initial current of the light source corresponding to the color channel is turned on, comprising: When the gray scale information of a color channel corresponding to pixel information is not 0, the initial current of the light source corresponding to the color channel is turned on at least one pixel time in advance.

4. The method of claim 1, wherein, The continuous pixel information comprises one row of pixel information, a plurality of rows of pixel information or one frame of pixel information.

5. The method of claim 1, wherein, The effective scanning time refers to the time when the scanning track of the scanning display device is used to display an image; the invalid scanning time refers to the time when the scanning track of the scanning display device is not used to display an image.

6. The method of claim 5, wherein, When the scanning mode of the scanning display device is a grid format scanning, the invalid scanning time comprises a plurality of fast axis scanning periods.

7. A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to realize the steps of the method of any one of claims 1-6.

8. A scanning display device, characterized by The scanning display device comprises a light source and a scanning display device for scanning the light emitted by the light source to be emitted; a memory having a computer program stored thereon; a processor configured to execute the computer program in the memory to realize the steps of the method of any one of claims 1-6.

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