Scanning track straight line detection method and scanning display device

Abstract

The invention discloses a scanning track straight line detection method and a scanning display device, and the method comprises the steps: detecting two delays of a light spot corresponding to a test pattern scanning two sensors through two sensors respectively, and judging whether the scanning track of a scanning device is a horizontal straight line or not through a delay difference value between the two delays. Therefore, the technical problems that in the prior art, a high-speed response photoelectric sensor and a high-speed signal processing circuit are needed for directly sampling a complete scanning track by adopting a sensor scheme, the implementation difficulty is large, and the cost is very high are solved; the technical effect that scanning track detection can be achieved through a small number of low-cost photoelectric sensors is achieved.

Description

Technical Field

[0001] The present invention relates to the field of projection display, and particularly to a method for detecting a straight scanning trajectory and a scanning display device. Background Art

[0002] In AR (Augmented Reality) display technology, MEMS galvanometers or FSD (fiber scanning display) can be used to achieve scanning display imaging. Scanning display requires closed-loop driving to ensure image stability. To achieve closed-loop driving, accurate detection of the scanning trajectory is required.

[0003] Due to the strict requirements for the appearance, size, and volume of AR glasses, the feedback device for detecting the scanning trajectory needs to be implemented without damaging the appearance of the glasses. In the prior art, various sensors are usually used to detect the trajectory to achieve trajectory correction.

[0004] Direct sampling of the complete scanning trajectory using a sensor solution requires a high-speed response optoelectronic sensor and a high-speed signal processing circuit, which is difficult to implement and costly. Summary of the Invention

[0005] The object of the present invention is to provide a method for detecting a straight scanning trajectory and a scanning display device, which can achieve scanning trajectory detection using a small number of low-cost optoelectronic sensors.

[0006] To achieve the above object of the invention, in a first aspect of an embodiment of the present invention, a method for detecting a straight scanning trajectory 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, and the scanning device is used to scan and emit the light emitted by the light source. The sensor includes two sensors located at different positions at the same horizontal height within the scanning area of the scanning device. The method includes:

[0007] Controlling the scanning display device to output a test image; the test image includes a test pattern, and the test pattern is a single-line horizontal line;

[0008] Respectively detecting two delays of the light spot corresponding to the test pattern output by the scanning device passing through the two sensors;

[0009] If the delay difference between the two delays is the same, it is determined that the scanning trajectory of the scanning device is a horizontal straight line; if the delay difference is not zero, it is determined that the scanning trajectory is not a horizontal straight line.

[0010] Optionally, the two sensors are respectively located in the central area and the edge area of the scanning area.

[0011] Optionally, when the two delays are different, the method further includes:

[0012] Controlling the scanning display device to output two test images respectively, where each of the two test images includes odd-row horizontal lines and even-row horizontal lines; for the odd rows, the scanning device scans from left to right, and for the even rows, the scanning device scans from right to left;

[0013] Detecting the two delays when the odd-row horizontal lines scan through the two sensors, and calculating an odd-row delay difference; and detecting the two delays when the even-row horizontal lines scan through the two sensors, and calculating an even-row delay difference;

[0014] If the odd-row delay difference is the same as the even-row delay difference, it indicates that the scanning trajectory is an inclined straight line; if the odd-row delay difference is different from the even-row delay difference, it indicates that the scanning trajectory is an ellipse.

[0015] Optionally, detecting the two delays when the light spot corresponding to the test pattern output by the scanning device scans through the two sensors includes:

[0016] During the scanning process, adjusting the display delay or driving phase of the scanning display device in the vertical direction, and recording the moment when the light spot corresponding to the test pattern scans through the sensor;

[0017] Calculating the delay corresponding to each sensor according to the moment when the light spot scans through the sensor and the relative position between the sensor and the test pattern.

[0018] Optionally, recording the moment when the light spot corresponding to the test pattern scans through the sensor includes:

[0019] During the scanning process, recording the signal intensity values detected by the sensor to obtain a signal intensity curve;

[0020] 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 through the sensor.

[0021] A second aspect of an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the method as described in the first aspect are implemented.

[0022] A third aspect of an embodiment of the present invention provides a scanning display device, including a scanning display device, sensors, 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;

[0023] A computer program is stored on the computer-readable storage medium, and when the program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0024] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0025] In the solution of the embodiment of the present invention, the scanning display device includes a scanning device and two sensors located at different positions at the same horizontal height within the scanning area of the scanning device; by respectively detecting two delays of the light spot corresponding to the test pattern scanning across the two sensors through the two sensors, and then judging whether the scanning trajectory of the scanning device is a horizontal straight line according to the situation of the delay difference between the two delays, thereby alleviating the technical problems existing in the prior art that a high-speed response optoelectronic sensor and a high-speed signal processing circuit are required to directly sample the complete scanning trajectory by using a sensor solution, which is difficult to implement and has a high cost, and achieving the technical effect of being able to detect the scanning trajectory by using a small number of low-cost optoelectronic sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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 use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts:

[0027] Figure 1 It is a schematic structural diagram of a scanning trajectory detection device provided by an embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of a test image and the moving direction of a light spot provided by an embodiment of the present invention;

[0029] Figure 3 It is a schematic diagram of the signal intensity curve of a sensor provided by an embodiment of the present invention;

[0030] Figure 4 It is a flowchart of a scanning trajectory straight line detection method provided by an embodiment of the present invention;

[0031] Figure 5 It is a schematic diagram of setting two sensors A and B at the same horizontal height provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] 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. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] In the embodiments of the present invention, the scanning display device can be a MEMS galvanometer or an optical fiber scanning display device, etc., and the corresponding scanning modes can be raster, Lissajous, spiral, etc. In the following embodiments, the scanning device is an optical fiber scanning display device and the scanning mode is raster as an example for description.

[0034] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of the scanning trajectory detection device provided by the embodiments of the present invention; the optical-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 scanning trajectory detection.

[0035] The sensor C can 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 the center position of the curve peak of the signal intensity curve is the center position of the light spot. Further, the moment corresponding to the center position of the curve peak of the signal intensity curve is used as the moment when the light spot sweeps across the sensor.

[0036] In projection image display, the center of the light spot energy is used as the geometric center of the light spot. When the light spot is not well focused and imaged, the position of the energy distribution center remains unchanged compared to when it is clearly focused. Therefore, in this solution, without the need for 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.

[0037] In another possible implementation manner, between the scanning device A and the sensor C, specific optical structures such as a lens and a micropore can also be used to optically focus the light emitted by the scanner on the photosensitive surface of the sensor to achieve detection of the light energy distribution.

[0038] 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).

[0039] Such as Figure 2As shown, when the test pattern in the test image includes a straight line, the position of the line center can be determined by detecting the signal intensity curve of the sensor. 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. Correspondingly, if the test pattern in the test image is a horizontal line, the light spot moves in the vertical direction.

[0040] During the scanning process, the horizontal 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 horizontal line sweeps across the center position of the sensor is determined. As Figure 3 shown, during the scanning process, the signal intensity values of the sensor are recorded in real time, and a curve can be obtained. 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 horizontal line in the test image aligns with the center of the sensor.

[0041] When the test image shows a vertical line, the sensor delay value when the center of the vertical line sweeps across the center position of the sensor can be determined by adjusting the display delay in the x direction or the driving phase delay of the fast axis for scanning.

[0042] When the test image shows a horizontal line, the sensor delay value when the center of the horizontal line sweeps across the center position of the sensor can be determined by adjusting the display delay in the y direction or the driving phase delay of the slow axis for scanning.

[0043] Through the above method, the measurement and calibration of the scanning trajectory can be achieved. Next, the scanning trajectory straight line detection method in the embodiments of the present invention will be described in conjunction with specific embodiments.

[0044] As Figure 4 shown, the scanning trajectory straight line detection method in the embodiments of the present invention includes the following steps.

[0045] Step 401, controlling the scanning display device to output a test image; the test image includes a test pattern, and the test pattern is a single-row horizontal line.

[0046] Step 402, respectively detecting two delays when the light spot corresponding to the test pattern output by the scanning device sweeps across the two sensors.

[0047] Step 403, if the delay difference between the two delays is the same, it is determined that the scanning trajectory of the scanning device is a horizontal straight line; if the delay difference is not zero, it is determined that the scanning trajectory is not a horizontal straight line.

[0048] In the embodiments of the present invention, two sensors are used to respectively detect two time delays when the light spot corresponding to the test pattern scans across the two sensors. Then, based on the time delay difference between the two time delays, it is determined whether the scanning trajectory of the scanning device is a horizontal straight line, thereby alleviating the technical problems existing in the prior art that directly sampling the complete scanning trajectory using a sensor solution requires a high-speed response optoelectronic sensor and a high-speed signal processing circuit, which are difficult to implement and costly. The technical effect of realizing the detection of the scanning trajectory using a small number of low-cost optoelectronic sensors is achieved.

[0049] For raster scanning, when the vibration amplitude of the optical fiber in the resonance region is relatively large, the movement trajectory of the fast axis of the optical fiber scanner is no longer an ideal horizontal straight line but an inclined straight line. Moreover, affected by driving performance, voltage fluctuations, etc., the movement trajectory of the fast axis will become an ellipse. Therefore, after determining that the scanning trajectory is no longer an ideal horizontal straight line, it is also necessary to detect whether the scanning trajectory is an inclined straight line or an ellipse.

[0050] As Figure 5 shown, at the same horizontal height, two sensors A and B are set at different positions, with B at the horizontal center and A close to the horizontal edge.

[0051] Set the test image as a single-line odd-frame horizontal line image, and use the line center detection method described in the foregoing embodiments to detect the time delay values t as and t bs when the horizontal line sweeps across the centers of sensor A and sensor B. Calculate dt s =t as -t bs . If dt s =0, it indicates that the actual display trajectory of the horizontal line (i.e., the scanning trajectory) is a horizontal straight line. If dt s is not 0, then set the test image as an even-line odd-frame horizontal line image, and use the line center detection method described in the foregoing embodiments to detect the time delay values t ad and t bd when the horizontal line sweeps across the centers of sensor A and sensor B. Calculate dt d =t ad -t bd .

[0052] If dt d =dt s , it indicates that the actual display trajectory is an inclined straight line.

[0053] If dt d !=dt s , it indicates that the actual display trajectory is an ellipse.

[0054] When the actual display trajectory is not a horizontal straight line, the voltage and phase of the correction signal can be adjusted to make dts = 0, the fast axis scanning trajectory can be tilted, and the ellipse problem can be corrected to a horizontal closed straight line.

[0055] Based on the same inventive concept, an embodiment of the present invention further provides 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 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 above scanning trajectory straight line detection method are implemented.

[0056] All features disclosed in this specification, or steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way.

[0057] 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.

[0058] 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 method or process step or any new combination disclosed.

Claims

1. A method for detecting a straight scanning trajectory, which is applied to a scanning display device, Characterized in that, The scanning display device includes a scanning display device and a sensor; 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; the sensor includes two sensors at different positions at the same horizontal height within the scanning area of the scanning device, and the method includes: Controlling the scanning display device to output a test image; the test image includes a test pattern, and the test pattern is a single row of horizontal lines; Respectively detecting two delays when the light spots corresponding to the test patterns output by the scanning device scan across the two sensors; If the delay difference between the two delays is the same, it is determined that the scanning trajectory of the scanning device is a horizontal straight line; if the delay difference is not zero, it is determined that the scanning trajectory is not a horizontal straight line.

2. The method according to claim 1, Characterized in that, The two sensors are respectively located in the central area and the edge area of the scanning area.

3. The method according to claim 1, Characterized in that, When the two delays are different, the method further includes: Controlling the scanning display device to output two test images respectively, and the two test images respectively include odd-row horizontal lines and even-row horizontal lines; the odd rows are scanned by the scanning device from left to right, and the even rows are scanned by the scanning device from right to left; Detecting two delays when the odd-row horizontal lines scan across the two sensors, and calculating an odd-row delay difference; and detecting two delays when the even-row horizontal lines scan across the two sensors, and calculating an even-row delay difference; If the odd-row delay difference is the same as the even-row delay difference, it indicates that the scanning trajectory is an inclined straight line; if the odd-row delay difference is different from the even-row delay difference, it indicates that the scanning trajectory is an ellipse.

4. The method according to claim 1, Characterized in that, Detecting two delays when the light spots corresponding to the test patterns output by the scanning device scan across the two sensors includes: During the scanning process, adjusting the display delay or driving phase of the scanning display device in the vertical direction, and recording the moment when the light spot corresponding to the test pattern scans across the sensor; Calculating the delay corresponding to each sensor according to the moment when the light spot scans across the sensor and the relative position between the sensor and the test pattern.

5. The method according to claim 4, Characterized in that, Recording the moment when the light spot corresponding to the test pattern scans across the sensor includes: During the scanning process, recording the signal intensity value 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.

6. A computer-readable storage medium, Characterized in that, A computer program is stored thereon, and when the program is executed by a processor, the steps of the method according to any one of claims 1-5 are implemented.

7. A scanning display device, Characterized in that, It includes 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, it implements the steps of the method according to any one of claims 1-5.

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