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, 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. The method comprises the following steps: acquiring effective scanning time and invalid scanning time of the scanning display device; selecting a performance mode to drive the light source in the effective scanning time; selecting an energy-saving mode to drive the light source in the invalid scanning time; wherein the initial current of the light source in the performance mode is greater than the initial current of the light source 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 causes the standby power consumption of the LD to be always maintained and the energy utilization rate to be 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, a readable storage medium and a 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 track, 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 requirements for the response of the LD, which needs to reach the target value of the light energy output of the LD 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 characteristics of the material and the device itself.

[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, a readable storage medium and a scanning display device, which are used to alleviate the technical problems in the prior art 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.

[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 to scan and emit light emitted by the light source, and the method comprises the following steps:

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

[0009] In the effective scanning time, the light source is driven in a performance mode; in the ineffective scanning time, the light source is driven in a power saving mode; wherein the initial current of the light source in the performance mode is greater than the initial current of the light source in the power saving mode.

[0010] Optionally, the light source is a laser, the initial current of the light source in the performance mode is a threshold current of the laser generating laser light; and the initial current of the light source in the power saving mode is 0.

[0011] Optionally, the effective scanning time refers to a time region in which a scanning track of the scanning display device is used for displaying an image; and the ineffective scanning time refers to a time region in which the scanning track of the scanning display device is not used for displaying an image.

[0012] Optionally, when the scanning mode of the scanning display device is a grid format scanning, the ineffective scanning time includes a plurality of fast axis scanning periods.

[0013] Optionally, the method further includes:

[0014] When the scanning display device enters the effective scanning time from the ineffective scanning time, the initial current of the light source is turned on in advance by at least one pixel time.

[0015] The second aspect of the embodiment of the present application provides a non-temporary computer readable storage medium, which stores a computer program, and the program is executed by a processor to realize the steps of the method according to the first aspect.

[0016] The third aspect of the embodiment of the present application provides a scanning display device, which includes:

[0017] A memory, which stores a computer program;

[0018] A processor, which is used to execute the computer program in the memory to realize the steps of the method according to the first aspect.

[0019] The one or more technical solutions in the embodiment of the present application have at least the following technical effects or advantages:

[0020] In the scheme 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 invalid scanning time, the power saving mode is selected to drive the light source; wherein the initial current of the light source in the performance mode is greater than the initial current of the light source in the power saving mode. 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 in the prior art that the driving current of the LD is always above the threshold current, which can cause 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. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used 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 other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 The scanning track schematic diagram of the grid format scanning mode provided by the embodiment of the present application;

[0023] Figure 2 The flowchart schematic diagram of the display driving method provided by the embodiment of the present application;

[0024] Figures 3A-3C The schematic diagram of the invalid scanning time and the effective scanning time provided by the embodiment of the present application;

[0025] Figure 4 The block diagram of the scanning display device provided by the embodiment of the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0027] In the embodiment of the present application, first, two driving modes of the LD are described.

[0028] The threshold current I th of the LD refers to the critical current at which the laser begins to emit laser; below I th , the LD does not emit laser.th At this point, spontaneous emission by the LD cannot produce controlled, high-energy-density, and highly monochromatic light. At the threshold I... th The response time of the LD is relatively long, reaching tens of nanoseconds. Therefore, during internal modulation, the current provided by the LD drive current usually consists of two parts: I1 = I th +I b , among which, I th For DC component (unchanged), I b For the bias current (the varying modulation current), through I b The change in signal allows the LD to respond quickly and achieve stable light energy output; in this invention, the above driving method is referred to as the I1 driving mode. Another driving method is the I2 driving mode, where I2 = I... b That is, there is no DC component, which leads to an increase in the LD response time.

[0029] Based on the information regarding the I1 and I2 driving modes described above, when the LD uses the I2 driving mode, if the color corresponding to the displayed image or pixel information is 0, the driving current of the LD corresponding to that color is 0, and the corresponding power consumption is P = 0. When the LD uses the I1 driving mode, if the color corresponding to the displayed image or pixel information is 0, the driving current corresponding to that color is I... th Its power consumption is P = U * I th U represents voltage, and P2 represents the LD standby power consumption, which is a fixed value that is always present as long as the power is on, regardless of the displayed content. The colors can be three channels: R (red), G (green), and B (blue).

[0030] In this embodiment of the invention, a fiber optic scanning display device with a raster scanning mode is used as an example for explanation. Figure 1 As shown, Figure 1 This is a schematic diagram of the fiber optic trajectory for raster scanning provided in an embodiment of the present invention. The grid in the background is a pre-defined virtual pixel grid. The scanner for raster scanning includes two actuators, providing fast-axis (horizontal) drive and slow-axis (vertical) drive respectively. Generally, the slow-axis drive frequency is lower than the fast-axis drive frequency. Under the combined effect of the vibrations generated by the two actuators, the fiber scans along the raster trajectory.

[0031] Due to the comprehensive factors such as the non-linear control of the optical fiber scanning track, the display time length 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 in the white screen display. Assuming that the ratio is r, the proportion of 1-r is the invalid scanning time (for information display), in other words, the effective scanning time refers to the time that the scanning track of the scanning display device is used for displaying images, and the invalid scanning time refers to the time that the scanning track of the scanning display device is not used for displaying images. In the invalid scanning time, if I th exists, it will always contribute to the power consumption P1, and in the effective scanning time, the black screen (for a certain color channel, the gray scale information of the color channel is 0) in the screen display will also contribute to the power consumption P2, at this time, the standby power consumption is composed of two parts P0=P1+P2.

[0032] Based on the above analysis, the embodiment of the present application provides a display driving method for reducing power consumption, as shown in the formula (1). Figure 2 Figure 2 The flowchart of the display driving method provided by the embodiment of the present application is shown, and the method comprises the following steps.

[0033] Step 201, acquiring the effective scanning time and the invalid scanning time of the scanning display device;

[0034] Step 202, in the effective scanning time, selecting a performance mode to drive the light source; in the invalid scanning time, selecting a power saving mode to drive the light source. Wherein, the initial current of the light source in the performance mode is greater than the initial current of the light source in the power saving mode.

[0035] Because 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 in the prior art, which causes the LD standby power consumption to always remain and the energy utilization rate to be low can be alleviated, and the technical effect of reducing the LD standby power consumption can be achieved.

[0036] In the embodiment of the present application, the initial current of the light source in the performance mode is the threshold current of the laser to generate laser; and the initial current of the light source in the power saving mode is 0.

[0037] In a possible implementation, in the invalid scanning time, the initial current of the light source is 0, that is, the threshold current I th ​To reduce power consumption, the I2 drive mode is maintained. Given the characteristics of the scan trajectory in the grid scanning method, the invalid scan time is typically several fast-axis scan cycles (a relatively long time). Therefore, the corresponding drive configuration conversion is easily implemented in the circuit. When the fiber optic scan enters the effective scan time region, I2 is enabled. th By maintaining the I1 drive mode, some power consumption of P1 can be eliminated.

[0038] In this embodiment of the invention, when the scan enters the effective scan time, the initial current of the light source can be turned on at least one pixel in advance, thereby ensuring the response speed of the light source.

[0039] In this embodiment of the invention, for normal display content, each pixel represents unpredictable information. To further reduce the standby power consumption of the LD, the information to be displayed by the scanning display device (such as pre-caching one line, several lines, or even one frame of display content) can be acquired within the effective scanning time. Then, based on the continuous pixel information content, for black screens in the display, the threshold current I is turned off. th When it is necessary to output and display information, selectively enable I in advance. th This achieves both the goal of reducing P2 and ensuring the response speed of the LD. In this mode, the actual drive current I1 consists of two parts: the changing I... th1 and I b .

[0040] For example, consider a series of pixel information with grayscale values ​​of 0-0-0-200-50-0-80-120-160-180. Assuming a conventional I1 driving mode, the corresponding threshold values ​​are 5-5-5-5-5-5-5-5-5-5, and the bias currents ib are 0-0-0-20-5-0-8-12-16-18. However, with an optimized driving method, it could be I... th The bias current i is 0-0-5-5-5-5-5-5-5-5. b The values ​​are 0-0-0-20-5-0-8-12-16-18 respectively. Alternatively, when the initial current of the light source is turned on in advance, the initial current of the light source is less than the threshold current, and then it is gradually increased to the threshold current. During this process, I is guaranteed to be... th +I b It can display pixel information. For example: I th They are 0-0-5-5-5-3-3-3-4-5, I b They are 0-0-0-20-5-0-10-14-17-18 respectively.

[0041] It can be seen that, in the scheme of the embodiment of the present application, the power consumption can be optimized according to different display information, and P2 is reduced. The above example is only illustrative. Since the opening current I th of the LD output laser is different, when the driving current is located at I th , the distance I th is farther, and the required lighting time is longer, the distance is closer, and the required time is shorter. Therefore, the above scheme is feasible in optimizing power consumption.

[0042] Next, the invalid scanning time and the effective scanning time in the embodiment of the present application are described.

[0043] In the imaging mode based on mechanical scanning, the scanning track path is mechanically continuous, and generally presents a triangular function track form. Taking 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. In terms of control difficulty, it is difficult to realize perfect straight line turning at the edge of the slow axis track, that is, the track control accuracy at the edge position is poor, and it is not suitable for imaging. The scanning track of this part of time is defined as invalid track, and the corresponding time is invalid scanning time.

[0044] Similarly, the slow axis is controlled to be a sawtooth wave or quasi-sawtooth wave track. After the slow axis reaches the edge, it will quickly back-scan in a very short time. Due to the continuity problem of the mechanical scanning track, this part of back-scan will occupy a certain time, and it is also not suitable for imaging and belongs to invalid scanning time. In addition, in the high frequency scanning of the fast axis, the track can be represented by a triangular function. In order to make the pixels uniform, a variable modulation signal is required to excite the LD to emit light. Due to the infinite difference between the boundary and the middle speed, the hardware implementation difficulty and cost increase dramatically. Therefore, the edge part of the fast axis track is not used for imaging, and this part also belongs to invalid scanning track.

[0045] Similarly, in the Lissajous scanning form, generally, the track part not used for information display is defined as invalid scanning track, and the corresponding time is invalid scanning time.

[0046] Taking the above example of grid format scanning, as shown in FIG. 1, Figure 3A , it is a two-dimensional scanning track of an optical fiber. The horizontal axis is the time measured by a single period of the fast axis. The fast axis half-period time length corresponds to the time from the leftmost end of the track to the adjacent rightmost end, that is, t1, t4. Since the speed changes according to a triangular function, considering the actual hardware driving limitation, the edge is not used for imaging, that is, t2-t1, t4-t3 is invalid scanning time, and t3-t2 is effective scanning time.

[0047] As shown in FIG. 2, Figure 3BAs shown in the figure, the slow axis trajectory of the optical fiber is an isosceles triangle mode, the horizontal axis is the time corresponding to the slow axis, and t6-t1 corresponds to one slow axis period, due to the difficulty in trajectory control and the actual response characteristics of the scanning display device, the speed changes obviously at the corner, which cannot be used for imaging and belongs to invalid scanning trajectory, and the specific invalid scanning time is t2-t1 and t4-t3.

[0048] As shown in the figure, the slow axis trajectory of the optical fiber is an isosceles triangle mode, the horizontal axis is the time corresponding to the slow axis, and t6-t1 corresponds to one slow axis period, due to the difficulty in trajectory control and the actual response characteristics of the scanning display device, the speed changes obviously at the corner, which cannot be used for imaging and belongs to invalid scanning trajectory, and the specific invalid scanning time is t2-t1 and t4-t3. Figure 3C 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 the 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, the standby power consumption of the light source is compressed to the minimum as much as possible, and the energy utilization rate is improved.

[0049] It should be noted that the scheme in the embodiment of the present application is not only suitable for optical fiber scanning, but also suitable for MEMS (English full name: Microelectro Mechanical Systems, Chinese name: micro-electro-mechanical system) and other laser scanning imaging systems.

[0050] Based on the same inventive concept, the embodiment of the present application further provides a projection display device 400, as shown in the figure, which includes a light source 401 used for outputting image light, a scanning display device 402 connected with the light source 401, light emitted by the light source 401 is coupled into the scanning display device 402 and is emitted through the scanning display device 402, a memory 403 having a computer program stored thereon, and a processor 404 used for executing the computer program in the memory 403 to realize the display driving method and control the light source 401 to emit light.

[0051] Figure 4 The embodiment of the present application further provides a computer readable storage medium including program instructions, which are executed by a 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.

[0052] The embodiment of the present application further provides a computer readable storage medium including program instructions, which are executed by a 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.

[0053] ​The embodiment of the present application also provides a computer program product, which contains a computer program capable of being executed by a programmable device, and the computer program has a code portion for executing the display driving method described above when executed by the programmable device.

[0054] All features disclosed in this specification, and / or all methods or processes disclosed in this specification, can be combined in any combination, provided the features and / or method steps are not mutually inconsistent.

[0055] Any feature in the present description, including any accompanying claims, abstract and drawings, can be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is one of a number of equivalent or similar features.

[0056] The application is not limited to the embodiments described above. The 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 in this specification, or any novel combination of steps of the methods or processes disclosed.

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, and the method comprises: acquiring the effective scanning time and the invalid scanning time of the scanning display device; in the effective scanning time, selecting a performance mode to drive the light source; acquiring the information to be displayed of the scanning display device, and driving the light source according to the continuous pixel information content in the information to be displayed; wherein for the black picture in the information to be displayed, the initial current of the light source is turned off; in the invalid scanning time, selecting a power saving mode to drive the light source; wherein the light source is a laser, the initial current of the light source in the performance mode is the threshold current of the laser to generate laser, and the initial current of the light source in the power saving mode is 0.

2. The method of claim 1, wherein, The effective scanning time refers to the time region in which the scanning track of the scanning display device is used to display an image, and the invalid scanning time refers to the time region in which the scanning track of the scanning display device is not used to display an image.

3. The method of claim 2, 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.

4. The method of claim 2, wherein, The method further comprises: when the scanning display device enters the effective scanning time from the invalid scanning time, the initial current of the light source is turned on at least one pixel moment in advance.

5. 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 in any one of claims 1-4.

6. 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 in any one of claims 1-4.

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