Delay adjustment method and scanning display device

Abstract

The invention discloses a delay adjusting method and a scanning display device. The scanning display device comprises a scanning display device and a sensor. The scanning display device comprises a light source and a scanning device. The method comprises the following steps: controlling the scanning display device to output a test image; detecting the moment when the light spot corresponding to the test pattern output by the scanning display device scans the sensor through the sensor; calculating the image delay between the scanning track of the scanning display device and the test image according to the moment when the light spot scans the sensor; and according to the image delay, adjusting the driving delay of the scanning display device so as to synchronize the scanning track and the display content of the scanning display device. The above scheme is used for solving the technical problem that in the prior art, the scanning track of the scanning display device and the display content are misplaced, so that the projection picture has errors, and the projection quality is improved.

Description

Technical Field

[0001] The present invention relates to the field of projection display, and particularly to a delay adjustment method and a scanning display device. Background Art

[0002] In projection display technology, MEMS galvanometers or FSD (fiber scanning display) can be used to achieve scanning display imaging. While scanning, the output of the light source is controlled, and the pixel point information on the image to be displayed is projected onto the imaging area one by one, thereby forming a projection screen.

[0003] During the actual scanning and projection process, affected by the stability of the system itself or external environmental disturbances, the scanning trajectory of the scanning display device may be misaligned with the display content, resulting in errors in the projection screen. Summary of the Invention

[0004] The object of the present invention is to provide a delay adjustment method and a scanning display device, which are used to solve the technical problem in the prior art that the scanning trajectory of the scanning display device is misaligned with the display content, resulting in errors in the projection screen, improve the projection quality, and provide a solution that can achieve delay adjustment with a small number of low-cost optoelectronic sensors.

[0005] To achieve the above object of the invention, in the first aspect of the embodiments of the present invention, a delay adjustment method is provided, which is applied to a scanning display device. The scanning display device includes a scanning display device and a sensor. The scanning display device includes a light source and a scanning device. The scanning device is used to scan and emit the light emitted by the light source. The method includes:

[0006] Controlling the scanning display device to output a test image, where the test image includes a test pattern with a specific shape;

[0007] Detecting, by the sensor, the moment when the light spot corresponding to the test pattern output by the scanning display device scans across the sensor;

[0008] Calculating, according to the moment when the light spot scans across the sensor, the image delay between the scanning trajectory of the scanning display device and the test image;

[0009] Adjusting the driving delay of the scanning display device according to the image delay, so that the scanning trajectory of the scanning display device is synchronized with the display content.

[0010] Optionally, the image delays are respectively a horizontal delay and a vertical delay; when adjusting the horizontal delay, the test pattern is a vertical line; when adjusting the vertical delay, the test pattern is a horizontal line.

[0011] Optionally, calculating an image delay between the scanning trajectory of the scanning display device and the test image according to the moment when the light spot scans across the sensor includes:

[0012] Calculating the image delay according to the moment when the light spot scans across the sensor and the relative position between the sensor and the test image.

[0013] Optionally, the sensor is located at the center position of the image display; and, the test pattern is located at the center position of the test image.

[0014] Optionally, the sensor includes two sensors at different positions at the same horizontal height, and there is a preset phase difference between the two sensors; the method further includes:

[0015] After calculating the image delay through one of the sensors, setting the driving delay of the scanning display device to scan within the current delay to the target delay; the target delay is calculated according to the preset phase difference and the scanning period;

[0016] During the scanning process, if the other sensor detects the light spot, it indicates that the image display is normal; if the other sensor does not detect the light spot, it indicates that the image display has been flipped left and right, and the current delay is corrected.

[0017] Optionally, detecting the moment when the light spot corresponding to the test pattern output by the scanning display device scans across the sensor through the sensor includes:

[0018] During the scanning process, recording the signal intensity values detected by the sensor to obtain a signal intensity curve;

[0019] Taking the moment corresponding to the center position of the curve peak of the signal intensity curve as the moment when the light spot scans across the sensor.

[0020] Optionally, the signal intensity value detected by the sensor is the signal intensity integral value of one frame or multiple frames of test images.

[0021] Optionally, adjusting the driving delay of the scanning display device includes:

[0022] Adjusting the phase delay of the driving signal applied to the scanning device.

[0023] Optionally, adjusting the driving delay of the scanning display device includes: adjusting the display delay of the light source.

[0024] In a second aspect of the embodiments of the present invention, a scanning display device is provided, including a scanning display device, a sensor, a processor, and a computer-readable storage medium; the scanning display device includes a light source and a scanning device, and the scanning device is configured to scan and emit the light emitted by the light source;

[0025] A computer program is stored on the computer-readable storage medium, and when the program is executed by the processor, it implements the steps of the method described in the first aspect.

[0026] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0027] In the solution of the embodiments of the present invention, the scanning trajectory detection device includes a scanning display device and a sensor; the sensor is used to detect the moment when the light spot corresponding to the test pattern output by the scanning display device scans across the sensor; then, according to the moment when the light spot scans across the sensor, calculate the image delay between the scanning trajectory of the scanning display device and the test image; and then, according to the image delay, adjust the driving delay of the scanning display device so that the scanning trajectory of the scanning display device is synchronized with the display content, thereby solving the technical problem in the prior art that the scanning trajectory of the scanning display device is misaligned with the display content, resulting in an incorrect projection image, and improving the projection quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings:

[0029] Figure 1 It is a schematic structural diagram of the scanning trajectory detection device provided by the embodiments of the present invention;

[0030] Figure 2 It is a schematic diagram of the test image and the moving direction of the light spot provided by the embodiments of the present invention;

[0031] Figure 3 It is a flowchart of the delay adjustment method provided by the embodiments of the present invention;

[0032] Figures 4A - 4C It is a schematic diagram of the relative displacement between the display content and the sensor provided by the embodiments of the present invention;

[0033] Figure 5 It is a schematic diagram of the signal intensity curve of another sensor provided by the embodiments of the present invention;

[0034] Figure 6 Schematic diagram of the scanning trajectory and the sensor provided by an embodiment of the present invention;

[0035] Figure 7 Schematic diagram of the signal intensity curve of another sensor provided by an embodiment of the present invention;

[0036] Figure 8 Schematic diagram of setting two sensors A and B provided by an embodiment of the present invention. Detailed implementation manners

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] In the embodiments of the present invention, the scanning display device may be a MEMS galvanometer or an optical fiber scanning display device, etc., and the corresponding scanning modes may be raster, Lissajous, spiral, etc. In the following embodiments, an optical fiber scanning display device is taken as the scanning display device and the raster scanning mode is taken as an example for description.

[0039] Please refer to Figure 1 , Figure 1 Schematic diagram of the structure of the scanning trajectory detection device provided by an embodiment of the present invention; the opto-mechanical structure of the scanning trajectory detection device includes a light source, a scanning device A, a lens B, a sensor C, and a waveguide lens D. Among them, part of the light output by the scanning device A is transmitted to the human eye through the waveguide lens D, and part passes through the waveguide lens D and enters the sensor C to achieve trajectory detection.

[0040] The sensor C may be a single-point light sensor, and the single-point light sensor converts the light intensity information irradiated on the photosensitive surface of the sensor into an electrical signal. When the light spot output by the scanning device A sweeps across the light sensor, the light intensity distribution of the light spot center sweeping across the sensor area can be recorded by the sensor, generating a signal intensity curve, and taking the moment corresponding to the center position of the curve peak of the signal intensity curve as the moment when the light spot sweeps across the sensor.

[0041] In projection image display, the center of the light spot energy is used as the geometric center of the light spot. The light spot is not well focused and imaged, and the position of the energy distribution center remains unchanged compared with the position when it is clearly focused. Therefore, in this solution, without an optical structure to achieve good focusing and imaging conditions, the light change center can still be determined through the energy distribution curve detected by the sensor.

[0042] In another possible implementation, between the scanning device A and the sensor C, the light emitted by the scanner can also be optically focused on the photosensitive surface of the sensor through specific optical structures such as lenses and micropores to achieve the detection of the light energy distribution.

[0043] In the embodiments of the present invention, the number of sensors can be one or more. When the number of sensors is multiple, different sensors respectively detect the moments when the light spots corresponding to the test patterns in the test image scan through each sensor.

[0044] In the embodiments of the present invention, for raster scanning, the scanning device includes a fast axis and a slow axis. The fast axis scans in the horizontal direction (x direction), and the slow axis scans in the vertical direction (y direction).

[0045] As Figure 2 shown, when the test pattern in the test image is a straight line, the position of the line center can be determined by detecting the signal intensity curve of the sensor. In order to eliminate the alignment error between the light spot and the sensor, when detecting the light spot, the test pattern in the test image can be designed as a line perpendicular to the moving direction of the light spot. As Figure 2 shown, the test pattern in the test image is a vertical line, and the light spot moves in the horizontal direction.

[0046] During the scanning process, the vertical line displacement can be achieved by adjusting the driving phase delay or the display delay. The position of the sensor is calibrated in advance, and the position of the sensor can be accurately known. Then, through the scanning method, the driving phase delay or the display delay when the center of the vertical line sweeps through the center position of the sensor is determined.

[0047] When the test image is displayed as a vertical line, adjusting the display delay in the x direction or the driving phase delay of the fast axis for scanning can determine the sensor delay value when the center of the vertical line sweeps through the center position of the sensor.

[0048] When the test image is displayed as a horizontal line, adjusting the display delay in the y direction or the driving phase delay of the slow axis for scanning can determine the sensor delay value when the center of the horizontal line sweeps through the center position of the sensor.

[0049] To reduce the system requirements, when detecting the horizontal delay, it is not necessary to detect the signal intensity of a single fast axis scanning period. The integral value of one or more frame displays can be calculated. Therefore, the cut-off frequency of the sensor low-pass filter can be much smaller than the fast axis scanning frequency and greater than the speed of adjusting the driving phase and the display delay.

[0050] Through the above method, the delay detection of the scanning display device can be achieved. Next, the delay adjustment method in the embodiments of the present invention will be described in combination with specific embodiments. As Figure 3 shown, the delay adjustment method includes the following steps.

[0051] Step 301: Control the scanning display device to output a test image, where the test image includes a test pattern with a specific shape.

[0052] Step 302: Detect, through the sensor, the moment when the light spot corresponding to the test pattern output by the scanning display device scans across the sensor.

[0053] Step 303: Calculate the image delay between the scanning trajectory of the scanning display device and the test image according to the moment when the light spot scans across the sensor.

[0054] Step 304: Adjust the driving delay of the scanning display device according to the image delay so that the scanning trajectory of the scanning display device is synchronized with the display content.

[0055] For the scanning display device, the image delay is respectively the horizontal delay and the vertical delay. When detecting the delays in different directions, different test patterns can be used; when adjusting the horizontal delay, the test pattern is a vertical line; when adjusting the vertical delay, the test pattern is a horizontal line. In the embodiments of the present invention, there is no limit to the line width of the horizontal or vertical line. The horizontal line can be very thick, and the actual pattern can also be a rectangle.

[0056] In scanning display, the display content needs to modulate the light source according to the scanning trajectory in time sequence to complete image display. If the fast-axis display content is not synchronized with the fast-axis trajectory, the display content will shift left and right. In scanning display, due to the phase difference between the fast-axis mechanical vibration phase and the driving signal phase, and the phase difference will change with the change of the system vibration response characteristics. To compensate for the phase difference, it is necessary to adjust the driving phase or add a display delay to the display drive. The two have the same effect on image display. In practical applications, the fast axis usually requires an additional correction driving signal in the y direction to ensure that the scanning trajectory is closed and not an ellipse. If the driving phase is adjusted, the correction phase synchronization adjustment is required to ensure that the fast-axis trajectory is closed.

[0057] As Figures 4A - 4C shown, by adjusting the display delay or the fast-axis driving phase, the relative displacement between the display content and the sensor can be realized, so as to realize the detection of the image of this row by the sensor.

[0058] During the scanning process, by recording the sensor signal intensity value in real time, a curve can be obtained. As Figure 5 shown, the delay t1 corresponding to the center position of the curve peak is the display delay or the driving phase when the center of the vertical line in the test image is aligned with the center of the sensor. Since the position of the sensor is fixed and the relative position of the sensor in the image is known, the correct image delay value can be obtained according to the method in the embodiments of the present invention. The image delay here refers to the horizontal delay.

[0059] In the embodiments of the present invention, for the convenience of description, asFigure 6 As shown, the starting position at the leftmost side of the scanning trajectory is defined as the 0-phase position of the fast-axis vibration trajectory. The 0-pi segment trajectory is an odd row, and the pi-2pi segment trajectory is an even row.

[0060] In the embodiment of the present invention, an example is given where the sensor is installed at the exact center of the image display position for illustration.

[0061] As Figure 6 shown, the fast axis sweeps across the sensor at pi / 4 and pi*3 / 4 respectively. Design an original image with a vertical line displayed at the exact center of the image and only on odd rows. That is, display the vertical line at the point of phase pi / 4. Adjust the phase delay of the drive signal (if the correction voltage is not 0, the phase of the correction voltage needs to be adjusted synchronously) so that the vertical line sweeps across the sensor, obtaining a curve as Figure 7 shown. Then, calculate the center position of the curve to obtain the t1 value. It can be concluded that when the fast-axis drive phase is t1, the pi / 4 position of the scanning vibration trajectory coincides with the sensor, the image is displayed normally, and the content displayed on the fast axis is synchronized with the fast-axis trajectory.

[0062] In the above scheme, it is also possible not to adjust the phase delay of the drive voltage, and it is also feasible to adjust the display delay.

[0063] In the embodiment of the present invention, the sensor may not be centered (i.e., the sensor part is installed at the exact center of the image display position), and the image may also be displayed on even rows. It can be corrected according to the position relationship between the vertical line position of the test image and the sensor position. And even if the position of the sensor is unknown, the phase calibration can be achieved by the following method.

[0064] First, during factory calibration:

[0065] Adjust the image delay correctly so that the odd and even row images coincide; record the current image delay d1;

[0066] Stepwise adjust the delay value within the range of d1-s and d1+s to make the light spot output by the scanning display device sweep across the sensor; in the embodiment of the present invention, the value of s is related to the specific characteristics of the scanning display device, such as characteristics like swing amplitude, light spot size, and consistency. The value of s needs to ensure that the light spot completely sweeps across the sensor, that is, s>d1+w1, where d1 is the light spot diameter and w1 is the width of the sensor photosensitive surface.

[0067] Record the sensor signal value, and use methods such as filtering and curve fitting to eliminate noise and reduce measurement errors;

[0068] Find the delay value d2 corresponding to the center axis of the curve peak;

[0069] Record Δd = d2 - d1 to complete the factory calibration.

[0070] When the scanner delay needs to be corrected:

[0071] Stepping and adjusting the delay value within the range of d1 - s and d1 + s to make the light spot sweep across the sensor;

[0072] Record the sensor signal value, and eliminate noise and reduce measurement error through methods such as filtering and curve fitting;

[0073] Find out the delay value d2’ corresponding to the central axis of the curve peak;

[0074] Calculate d1’ = d2’ - Δd; where d1’ is the drive delay corresponding to the coincidence of the current odd and even row images.

[0075] In the above solution, when setting the drive delay to scan within the range of 0 - 2pi, two peaks t1 and t2 will be obtained, and t1 - t2 = T / 2, where T is a fast axis scanning period. Among them, one peak is the delay when the light spot sweeps across the sensor at the odd frame position, and the other is the delay when scanning the sensor at the even frame position. Since a single sensor cannot determine the translation direction of the image during the process of adjusting the delay, if the image is flipped left and right, a single sensor cannot distinguish whether the image scanned across the sensor is an odd frame image or an even frame image. In the embodiments of the present invention, the following two implementation manners can also be used to determine whether the image is flipped left and right.

[0076] In a possible implementation manner, as Figure 8 shown, an additional sensor can be added, and by comparing the central positions of the curve peaks of the signal intensity curves detected by the two sensors, it is determined whether the image is flipped left and right.

[0077] In Figure 8 , assume that the left sensor is A, the central sensor is B, and the phase difference between AB is dP ab , after correcting the drive phase delay through B, set the drive delay to scan from the current value to the target delay t1 - 2*dP ab / 2pi*T x within, T x is the fast axis scanning period. If the sensor A detects the light spot, it indicates that the image is displayed normally and is not flipped left and right. If the sensor A does not detect the light spot, it indicates that the phase difference between the current trajectory and the expected trajectory is pi, and the displayed image is flipped left and right. Then, correct the current drive delay by pi, and the corrected delay is t1’ = t1 + T x / 2. Among them, the target delay can be calculated according to the preset phase difference and scanning period between the two sensors.

[0078] In another possible implementation manner, before detecting the drive phase delay by using the above method, use an external device for calibration to determine the initial delay value t of the drive delay int. During the normal use of the product, due to factors such as device aging and external conditions, the phase drift of the fast-axis vibration response usually does not exceed T x / 2. Therefore, it can be approximately considered that t int -t < T x . Therefore, the values that make t int -t greater than T x can be directly eliminated

[0079] In the embodiments of the present invention, the left and right offset of the image center position will cause measurement errors, and the following method can be used to eliminate them. If t 1 -t 2 = T / 2 (T is a fast-axis scanning period), it indicates that the image center has no offset. If t 1 -t 2 ≠T / 2, it indicates that the center position is offset. t 1 -t 2 -T / 2 is the center offset amount

[0080] In the embodiments of the present invention, detection and calculation are performed through a small number of low-cost single-point sensors, and it is not necessary to sample the complete scanning trajectory of the scanning device, thus avoiding the use of high-speed response photoelectric sensors and high-speed signal processing circuits, which can reduce the implementation difficulty and save costs

[0081] Based on the same inventive concept, the embodiments of the present invention also provide a scanning display device, including a scanning display device, a sensor, a processor, and a computer-readable storage medium; the scanning display device includes a light source and a scanning device, and the scanning device is used to scan and emit the light emitted by the light source; a computer program is stored on the computer-readable storage medium, and when the program is executed by the processor, the steps of the above-mentioned delay adjustment method are implemented

[0082] All the features disclosed in this specification, or all the steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way

[0083] Any feature disclosed in this specification (including any additional claims, abstract, and drawings), unless specifically stated, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically stated, each feature is only an example of a series of equivalent or similar features

[0084] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, as well as any new combination of the steps of any new method or process disclosed

Claims

1. A delay adjustment method, which is applied to a scanning display device, characterized in that, the scanning display device includes a scanning display component and a sensor; the scanning display component includes a light source and a scanning device, and the scanning device is used to scan and emit the light emitted by the light source, and the method includes: controlling the scanning display component to output a test image, and the test image includes a test pattern with a specific shape; detecting, by the sensor, the moment when the light spot corresponding to the test pattern output by the scanning display component scans across the sensor; calculating, according to the moment when the light spot scans across the sensor, the image delay between the scanning trajectory of the scanning display component and the test image; adjusting the driving delay of the scanning display component according to the image delay, so that the scanning trajectory of the scanning display component is synchronized with the display content.

2. The method according to claim 1, characterized in that, the image delays are respectively a horizontal delay and a vertical delay; when adjusting the horizontal delay, the test pattern is a vertical line; when adjusting the vertical delay, the test pattern is a horizontal line.

3. The method according to claim 1, characterized in that, calculating, according to the moment when the light spot scans across the sensor, the image delay between the scanning trajectory of the scanning display component and the test image includes: calculating the image delay according to the moment when the light spot scans across the sensor and the relative position between the sensor and the test image.

4. The method according to claim 3, characterized in that, the sensor is located at the center position of the image display; and, the test pattern is located at the center position of the test image.

5. The method according to claim 3, characterized in that, the sensor includes two sensors located at different positions at the same horizontal height, and there is a preset phase difference between the two sensors; the method further includes: after calculating the image delay through one of the sensors, setting the driving delay of the scanning display component to scan within the range from the current delay to the target delay; the target delay is calculated according to the preset phase difference and the scanning period; during the scanning process, if the other sensor detects a light spot, it indicates that the image display is normal; if the other sensor does not detect a light spot, it indicates that the image display has been flipped left and right, and the current delay is corrected.

6. The method according to claim 1, characterized in that, detecting, by the sensor, the moment when the light spot corresponding to the test pattern output by the scanning display component scans across the sensor includes: during the scanning process, recording the signal intensity values detected by the sensor to obtain a signal intensity curve; taking the moment corresponding to the center position of the curve peak of the signal intensity curve as the moment when the light spot scans across the sensor.

7. The device according to claim 6, characterized in that, the signal intensity value detected by the sensor is the signal intensity integral value of one frame or multiple frames of test images.

8. The method according to claim 1, characterized in that, adjusting the driving delay of the scanning display component includes: adjusting the phase delay of the driving signal applied to the scanning device.

9. The method according to claim 1, wherein, adjusting the driving delay of the scanning display device includes: adjusting the display delay of the light source.

10. A scanning display device, wherein, comprising a scanning display device, a sensor, a processor, and a computer-readable storage medium; the scanning display device includes a light source and a scanning device, and the scanning device is configured to scan and emit the light emitted by the light source; a computer program is stored on the computer-readable storage medium, and when the program is executed by the processor, the steps of the method according to any one of claims 1-9 are implemented.

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