CN115731825A - Display driving method, readable storage medium and scanning display device - Google Patents
Display driving method, readable storage medium and scanning display device Download PDFInfo
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- CN115731825A CN115731825A CN202211468135.1A CN202211468135A CN115731825A CN 115731825 A CN115731825 A CN 115731825A CN 202211468135 A CN202211468135 A CN 202211468135A CN 115731825 A CN115731825 A CN 115731825A
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Abstract
The invention discloses a display driving method, a readable storage medium and a scanning display device, wherein the method is applied to the scanning display device and comprises the following steps: acquiring effective scanning time and ineffective scanning time of a scanning display device; selecting a performance mode to drive the light source within the effective scanning time; 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; selecting a power-saving mode to drive the light source in the invalid scanning time; and setting the initial current of the light source to be a preset value in the power-saving mode. Because the initial current of the light source is different in different time periods, the technical problems that the driving current of the LD is always above the threshold current, the standby power consumption of the LD is always kept and the energy utilization rate is low in the prior art can be solved.
Description
Technical Field
The present invention relates to the field of projection display, and in particular, to a display driving method, a readable storage medium, and a scanning display device.
Background
The imaging principle of the fiber scanning display technology (FSD) is that an optical fiber is driven by an optical fiber scanning display device to perform a motion of a predetermined two-dimensional scanning track, a light source is modulated to output light corresponding to each pixel point of an image to be displayed, and then the light corresponding to each pixel point of the image to be displayed is projected onto a projection plane one by one through the optical fiber to form a projection picture.
The optical fiber scanning display technology and the Laser display technology of the LD (Laser Diode) internal modulation are combined to be considered as an ideal optical display scheme on the AR (Augmented Reality) device. In the display process, the LD is frequently required to be completely turned off (not emitting light) at the pixel level and then turned on to a certain target brightness instantly, and the requirement on the response speed of the LD is high.
Considering the actual display frame rate and specification requirements, and the principle of the fiber scanning display technology, the fiber scanning display technology has extremely high response requirements on the LD, and needs to reach the target value to be displayed from 0 instant within the time range of ns or even sub-ns level. In addition, the response time of the LD, which is determined by the light emitting principle, is limited by the material and the characteristics of the device itself.
In order to reduce the response time of the LD during fast modulation, it is conventional to keep the drive current of the LD above a threshold, but this way will result in that the standby power consumption of the LD is always maintained and the energy utilization rate is low.
Disclosure of Invention
The invention aims to provide a display driving method, a readable storage medium and a scanning display device, which are used for solving the technical problems that in the prior art, the driving current of an LD is always above a threshold current, so that the standby power consumption of the LD is always kept and the energy utilization rate is low.
In order to achieve the above object, a first aspect of embodiments of the present invention provides a display driving method applied to a scanning display apparatus, where the scanning display apparatus includes a light source and a scanning display device, and the scanning display device is configured to scan and emit light emitted from the light source, where the method includes:
acquiring effective scanning time and ineffective scanning time of the scanning display device;
selecting a performance mode to drive the light source within the effective scanning time; 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;
selecting a power-saving mode to drive the light source in the invalid scanning time; and setting the initial current of the light source to be a preset value in the power-saving mode.
Optionally, the light source is a laser, the initial current of the light source in the performance mode changes within a preset current interval, the minimum value of the preset current interval is 0, and the maximum value is a threshold current of the laser generated by the laser; the preset value of the initial current of the light source in the power-saving mode is 0.
Optionally, in the performance mode, setting the initial current of the light source according to pixel information to be displayed by the scanning display device includes:
under the performance mode, acquiring pixel information to be displayed by the scanning display device; the pixel information to be displayed comprises pre-cached continuous pixel information;
when the gray scale information of the color channel corresponding to the continuous pixel information is 0, the initial current of the light source corresponding to the color channel is cut off; and when the gray scale information of the color channel corresponding to the pixel information is not 0, starting the initial current of the light source corresponding to the color channel.
Optionally, when the gray scale information of the color channel corresponding to the pixel information is not 0, turning on the initial current of the light source corresponding to the color channel includes:
and when the gray scale information of the color channel corresponding to the pixel information is not 0, starting the initial current of the light source corresponding to the color channel in advance at least one pixel moment.
Optionally, the continuous pixel information includes one line of pixel information, multiple lines of pixel information, or one frame of pixel information.
Optionally, the effective scanning time refers to a time when a scanning track of the scanning display device is used for displaying an image; the invalid scanning time refers to a time when a scanning track of the scanning display device is not used for displaying an image.
Optionally, when the scan mode of the scanning display device is raster scan, the invalid scan time includes a plurality of fast axis scan cycles.
A second aspect of embodiments of the present invention provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the method according to the first aspect.
A third aspect of embodiments of the present invention provides a scanning display device, including:
a memory having a computer program stored thereon;
a processor for executing the computer program in the memory to implement the steps of the method according to the first aspect.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
in the scheme of the embodiment of the invention, in the running process of the AR equipment, the effective scanning time and the invalid scanning time of the scanning display device are obtained; selecting a performance mode to drive the light source within the effective scanning time; 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; selecting a power-saving mode to drive the light source in the invalid scanning time; and setting the initial current of the light source to be a preset value in the power-saving mode. According to the effective scanning time and the ineffective scanning time of the scanning display device, the initial currents of the light source are different in different time periods, so that the technical problems that in the prior art, the driving current of the LD is always above the threshold current, the standby power consumption of the LD is always kept, and the energy utilization rate is low can be solved, and the technical effect of reducing the standby power consumption of the LD can be achieved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive exercise:
FIG. 1 is a schematic view of a scanning track of a grid scanning mode according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a display driving method according to an embodiment of the present invention;
FIGS. 3A-3C are schematic diagrams of an invalid scan time and an effective scan time provided by an embodiment of the present invention;
fig. 4 is a block diagram of a scanning display device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
In the embodiment of the present invention, two driving methods of the LD will be described first.
Threshold current I of LD th Means that the critical current of laser generated by the laser is higher than I th When the laser is started, the LD starts to emit laser; is less than I th When LD is spontaneously emitted, it is impossible to form light having a controlled, high energy density and good monochromaticity. At a threshold value I th Hereinafter, the LD response time is long, and may reach several tens of ns. Therefore, in the internal modulation, the current supplied by the LD driving current is generally two-part I1= I th +I b Wherein, I th As a direct current component (unchanged), I b For bias current (varying modulation current), by I b The signal change makes the LD respond quickly to achieve stable light energy output, and the driving mode is referred to as I1 driving mode in the present invention. Another driving mode is I2 driving mode, I2= I b I.e., no dc component, with the accompanying problem that the LD response time length increases.
Based on the information of the I1 driving mode and the I2 driving mode, when the LD adopts the I2 driving mode, if the color corresponding to the display screen or the pixel information is 0, the driving current of the LD corresponding to the color is 0, and the corresponding electrical power consumption is P =0. When the LD adopts I1 driving mode, if the color corresponding to the display frame or pixel information is 0The driving current corresponding to the color is I th Its electric power consumption is P = U I th U is the voltage, and P2 is the LD standby power consumption, i.e., a fixed value that is always present as long as the device is turned on, regardless of the display content. The color can be three color channels of R (red), G (green) and B (blue).
In the embodiment of the present invention, an optical fiber scanning display device is taken, and a corresponding scanning mode is a grid type scanning as an example, as shown in fig. 1, fig. 1 is a schematic diagram of an optical fiber track of the grid type scanning provided in the embodiment of the present invention, and a grid in the background is a virtual pixel grid which is artificially divided. For a grid-type scanning scanner, the scanner includes two actuators, which respectively provide fast axis direction (horizontal) driving and slow axis direction (vertical) driving, generally speaking, the slow axis direction driving frequency is less than the fast axis direction driving frequency, and the optical fiber scans along a grid-type track under the synergistic effect of the vibrations generated by the two actuators.
Due to the fact that comprehensive factors of the optical fiber scanning track in all aspects such as nonlinear control, display duration specificity, energy uniformity correction requirements, circuit chip processing requirements and cost control are determined, only one part of the actual scanning track is used for displaying information, and the rest of the actual scanning track is not utilized. The effective scan utilization of fiber scan display technology can be defined as the ratio of the track duration for information display to the track repetition period for mechanical scanning during white frame display. Assuming that the ratio is r, the proportional time of 1-r is the invalid scanning time (for information display), in other words, the valid scanning time refers to the time of the scanning track of the scanning display device for displaying the image; the invalid scanning time refers to a time when a scanning track of the scanning display device is not used for displaying an image.
During the invalid scanning time, if I th There is a case where partial power consumption P1 is always contributed, and during the effective scanning time, power consumption P2 is also contributed to a black screen (for a certain color channel, the gradation information of the color channel is 0) during screen display, and at this time, standby power consumption is constituted by two parts, P0= P1+ P2.
Based on the above analysis, an embodiment of the present invention provides a display driving method for reducing power consumption, as shown in fig. 2, where fig. 2 is a schematic flow diagram of the display driving method provided in the embodiment of the present invention, and the method includes the following steps.
Because the initial current of the light source is different in different time periods, the technical problems that the driving current of the LD is always above the threshold current, the standby power consumption of the LD is always kept and the energy utilization rate is low in the prior art can be solved, and the technical effect of reducing the standby power consumption of the LD can be realized.
In the embodiment of the invention, the initial current of the light source in the performance mode is changed in a preset current interval, wherein 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 of the laser generated by the laser th . In other words, in the performance mode, the driving mode of each laser and the corresponding light source initial current are dynamically adjusted according to the pixel information to be displayed, so that the light source initial current changes in a preset current interval. And under the power saving mode, driving the light source according to an I2 driving mode, wherein the preset value of the initial current of the light source is 0.
In particular, the threshold current I is selectively turned off during the inactive scan time th The I2 driving mode is maintained to reduce power consumption, and according to the characteristic of the scanning track of the grid scanning mode, the invalid scanning time is usually several fast axis scanning periods (longer time), so that the corresponding driving configuration conversion can be easily realized on the circuit. When the optical fiber scanning enters from the invalid scanning time region to the valid scanning time regionOpening of th The I1 driving mode is maintained, so that the P1 part power consumption can be eliminated. In the embodiment of the invention, when the optical fiber scanning enters the effective scanning time, at least one pixel moment can be advanced, and the initial current of the light source is started, so that the response speed of the light source is ensured.
For normal display content, each pixel belongs to unpredictable information. Therefore, in the effective scanning time, the information to be displayed of the scanning display device (such as the display content of one line, several lines, even one frame buffered in advance) needs to be acquired, and then the threshold current I is turned off for the black picture in the picture display according to the continuous pixel information content th When the display information needs to be output, the I is selectively started in advance th Not only can the purpose of reducing P2 be achieved, but also the response speed of LD can be ensured, namely, in the mode, the actual driving current I1 is composed of two parts, and the changed I th1 And I b 。
For example: the gray scale of some continuous pixel information is 0-0-0-200-50-0-80-120-160-180, assuming that according to the conventional I1 driving mode, the corresponding threshold is 5-5-5-5-5-5-5-5, the bias current ib is 0-0-0-20-5-0-8-12-16-18, respectively, and the driving mode can be I th Respectively 0-0-5-5-5-5-5-5-5-5, bias current i b 0-0-0-20-5-0-8-12-16-18, or when the initial current of the light source is started in advance, the initial current of the light source is smaller than the threshold current and then gradually increased to the threshold current, and in the process, I is ensured th +I b The pixel information display can be realized. For example: i is th Are respectively 0-0-5-5-5-3-3-4-5,I b Respectively 0-0-0-20-5-0-10-14-17-18.
It can be seen that, in the scheme of the embodiment of the present invention, power consumption can be optimized according to different display information, so that P2 is reduced, and the above example is only an illustrative example. The starting current I of laser output by LD th When the driving current is at I th Distance I when following th The longer the required lighting time is, the closer the distance is, the shorter the required time is, and therefore, the above-described scheme is feasible in optimizing power consumption.
Next, the invalid scanning time and the valid scanning time in the embodiment of the present invention will be explained.
Based on the imaging mode of mechanical scanning, the scanning track path is mechanically continuous and generally presents a track form of trigonometric function. Taking grid type 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 by a 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 of the edge position is poor, and the scanning track of the partial time is defined as an invalid track, and the corresponding time is the invalid scanning time.
Similarly, the slow axis is controlled to be a sawtooth wave or quasi-sawtooth wave track, and the slow axis is quickly retraced in a very short time after reaching the edge, and due to the continuity problem of a mechanical scanning track, the retracing of the part can occupy a certain time, is not suitable for imaging and belongs to invalid scanning time; in addition, the trace of the fast axis high frequency scanning can be expressed by a trigonometric function, in order to make the pixel uniform, a variable modulation signal is needed to excite the LD to emit light, and the difference between the boundary speed and the intermediate speed is infinite, so the difficulty and the cost of hardware realization are increased greatly, therefore, the trace of the edge part of the fast axis is not used for imaging, and the part is also attributed to an invalid scanning trace.
The lissajous scanning forms are similar, and in general, the track part which is not used for information display is defined as an invalid scanning track, and the corresponding time is the invalid scanning time.
Following the example of the grid-type scanning described above, as shown in fig. 3A, the horizontal axis is the time measured by the fast axis single period, the half period length of the fast axis corresponds to the time from the leftmost end of the track to the rightmost end of the track, i.e., t1, t4, since the speed varies according to a trigonometric function, considering the limitation of the actual hardware driving, the edge is not used for imaging, i.e., t2-t1, t4-t3, is the invalid scanning time, and t3-t2 is the valid scanning time.
As shown in fig. 3B, the trajectory of the slow axis of the optical fiber is an isosceles triangle pattern, the horizontal axis is the time corresponding to the slow axis, and one slow axis period corresponds to t6-t1, and due to the difficulty of trajectory control and the actual response characteristics of the scanning display device, the speed at the corner changes significantly, and thus the trajectory cannot be used for imaging, and also belongs to an invalid scanning trajectory, specifically t2-t1, t4-t3, and t6-t5.
As shown in fig. 3C, the scanning trajectory is another form, i.e., quasi-sawtooth, the horizontal axis corresponds to time, the actual motion trajectory of the slow axis of the optical fiber is plotted, and t3-t1 corresponds to a slow axis period, and similarly, due to the control difficulty and the actual response characteristics of the scanning display device, the time period in which the speed changes drastically and is not used for imaging belongs to the invalid scanning time, specifically t2-t1.
In the embodiment of the invention, the lasers comprise R, G, B three-color lasers, and in AR display, the whole display area does not always keep all three colors and simultaneously has gray information which is not 0, so that the lasers of each color can be independently controlled, the driving modes of the lasers can be flexibly and dynamically adjusted, the image display quality is ensured, the standby power consumption of a light source is compressed to the lowest as possible, and the energy utilization rate is improved.
It should be noted that the scheme in the implementation of the present invention is not only suitable for fiber scanning, but also suitable for laser scanning imaging Systems such as MEMS (micro electro Mechanical Systems, chinese name: micro electro Mechanical Systems).
Based on the same inventive concept, an embodiment of the present invention further provides a projection display apparatus 400, as shown in fig. 4, including a light source 401, where the light source 401 is configured to output image light; a scanning display device 402 connected to a light source 401, light emitted from the light source 401 being coupled into the scanning display device 402 and emitted through the scanning display device 402, a memory 403 on which a computer program is stored; a processor 404, configured to execute the computer program in the memory 403 to implement the above-mentioned display driving method, and control the light source 401 to emit light.
Embodiments of the present invention also provide a computer readable storage medium including program instructions, which when executed by a processor implement the steps of the above-described display driving method. For example, the computer readable storage medium may be a memory, and the program instructions may be executed by a processor of a projection display apparatus to perform the display driving method described above.
Embodiments of the present invention also provide a computer program product comprising a computer program executable by a programmable apparatus, the computer program having code portions for performing the above-described display driving method when executed by the programmable apparatus.
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.
Claims (9)
1. A display driving method is applied to a scanning display device, and is characterized in that the scanning display device comprises a light source and a scanning display device, the scanning display device is used for scanning and emitting light emitted by the light source, and the method comprises the following steps:
acquiring effective scanning time and ineffective scanning time of the scanning display device;
selecting a performance mode to drive the light source within the effective scanning time; 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;
selecting a power-saving mode to drive the light source in the invalid scanning time; and setting the initial current of the light source to be a preset value in the power-saving mode.
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 within a preset current interval, the minimum value of the preset current interval is 0, and the maximum value is a threshold current of the laser to generate laser light; 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 in the performance mode, setting the light source initial current according to pixel information to be displayed by the scanning display device comprises:
under the performance mode, acquiring pixel information to be displayed by the scanning display device; the pixel information to be displayed comprises pre-cached continuous pixel information;
when the gray information of the 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 cut off; and when the gray scale information of the color channel corresponding to the pixel information is not 0, starting the initial current of the light source corresponding to the color channel.
4. The method of claim 3, wherein turning on the initial current of the light source corresponding to the color channel when the gray scale information of the color channel corresponding to the pixel information is not 0 comprises:
and when the gray scale information of the color channel corresponding to the pixel information is not 0, starting the initial current of the light source corresponding to the color channel in advance at least one pixel moment.
5. The method of claim 3, wherein the consecutive pixel information comprises a line of pixel information, a plurality of lines of pixel information, or a frame of pixel information.
6. The method of claim 1, wherein the effective scan time is a time for a scan trajectory of the scanning display device to display an image; the invalid scanning time refers to a time when a scanning track of the scanning display device is not used for displaying an image.
7. The method of claim 6, wherein the inactive scan time includes a plurality of fast axis scan cycles when a scan mode of the scanning display device is raster scan.
8. A non-transitory computer readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 7.
9. The scanning display device is characterized by comprising a light source and a scanning display device, wherein the scanning display device is used for scanning and emitting light emitted by the light source;
a memory having a computer program stored thereon;
a processor for executing the computer program in the memory to carry out the steps of the method of any one of claims 1 to 7.
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| CN202211468135.1A CN115731825A (en) | 2022-11-22 | 2022-11-22 | Display driving method, readable storage medium and scanning display device |
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