Swing detection method and scanning display device

Abstract

The invention discloses a swing detection 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; wherein the test image comprises a test pattern with a specific shape; in the scanning process, the driving voltage applied to the scanning device is gradually increased, the moment when a light spot corresponding to a test pattern output by the scanning device scans the sensor is detected through the sensor, and the current driving voltage corresponding to the current moment is recorded; and determining that the swing of the scanning track under the current driving voltage is a target swing corresponding to the position of the sensor. According to the scheme, a new scheme for detecting the optical fiber swing is provided, feedback control is carried out on the optical fiber swing, and the image stability is kept.

Description

Technical Field

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

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

[0003] In FSD scanning display technology, the long-term stability of the fiber swing amplitude is crucial for maintaining the constancy of the image size. However, due to device aging and changes in environmental conditions, the fiber swing amplitude may change even though the driving signal of the fiber scanning device remains unchanged.

[0004] To maintain image stability, it is necessary to detect the fiber swing amplitude and introduce feedback control. The purpose of this solution is to provide a new solution for detecting the fiber swing amplitude. Summary of the Invention

[0005] The purpose of the present invention is to provide a swing amplitude detection method and a scanning display device, providing a new solution for detecting the fiber swing amplitude.

[0006] To achieve the above object of the invention, in the first aspect of the embodiments of the present invention, a swing amplitude detection 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, and the scanning device is configured to scan and output the light emitted by the light source. The method includes:

[0007] Controlling the scanning display device to output a test image; wherein, the test image includes a test pattern with a specific shape, and the position of the test pattern in the test image corresponds to the position of the sensor in the scanning area of the scanning device;

[0008] During the scanning process, gradually increase the driving voltage applied to the scanning device, detect, by the sensor, the moment when the light spot corresponding to the test pattern output by the scanning device scans across the sensor, and record the current driving voltage corresponding to the current moment;

[0009] Determine that the swing amplitude of the scanning trajectory at the current driving voltage is the target swing amplitude corresponding to the position of the sensor.

[0010] Optionally, the scanning display device includes one sensor, and the sensor is located at the edge of the scanning area of the scanning device.

[0011] Optionally, the method further includes:

[0012] Calculate the rated voltage required for the optical fiber to reach the rated swing according to the target swing, the rated swing of the optical fiber, the current driving voltage, and a set functional relationship.

[0013] Optionally, the scanning display device includes two sensors, which are respectively located at different positions on the edge of the scanning area of the scanning device; the method further includes:

[0014] Based on the two sensors, calculate the rated voltage required for the optical fiber to reach the rated swing respectively;

[0015] If the rated voltages obtained from the two calculations are different, it indicates that the center position of the scanned image of the scanning device is shifted.

[0016] Optionally, the scanning display device further includes a sensor disposed at the center position of the scanning area; the method further includes:

[0017] Control the scanning display device to output a test image, where the test image includes a test pattern with a specific shape;

[0018] Record the moment when the light spot corresponding to the test pattern output by the scanning display device scans through the center position sensor;

[0019] 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 through the center position sensor;

[0020] Adjust the driving delay of the scanning display device according to the image delay, so that the scanning trajectory of the scanning display device and the display content are synchronized, and the shift of the center position of the scanned image is eliminated.

[0021] Optionally, the scanning display device further includes a sensor disposed outside the scanning area; a standard delay difference is stored in the scanning display device, and the method further includes:

[0022] Control the scanning display device to output a test image, where the test image includes a test pattern with a specific shape;

[0023] Adjust the driving delay of the scanning display device and record the current delay corresponding to the maximum signal intensity detected by the sensor outside the scanning area;

[0024] Calculate the difference between the current delay and the standard delay difference, and adjust the driving delay of the scanning display device based on the difference, so that the scanning trajectory of the scanning display device is synchronized with the display content, and the offset of the center position of the scanned image is eliminated.

[0025] In a second aspect of the embodiments of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0026] In a third 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 used to scan and emit the light emitted by the light source;

[0027] The computer-readable storage medium stores a computer program, and when the program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0028] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0029] In the solution of the embodiments of the present invention, the scanning display device includes a scanning display device and a sensor. In the test image output by the scanning display device, the position where the test pattern is located corresponds to the position of the sensor in the scanning area of the scanning device. During the scanning process, the driving voltage applied to the scanning device is gradually increased. When the light spot corresponding to the test pattern scans across the sensor, it means that the fiber swing amplitude reaches the target swing amplitude. Thus, the fiber swing amplitude is detected through the sensor, and a new solution for detecting the fiber swing amplitude is provided to perform feedback control on the fiber swing amplitude and maintain image stability. Description of the Drawings

[0030] 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, other drawings can be obtained based on these drawings without creative efforts:

[0031] Figure 1 It is a schematic structural diagram of the scanning trajectory detection device provided by the embodiments of the present invention;

[0032] 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;

[0033] Figure 3 It is a flowchart of the swing amplitude detection method provided by the embodiments of the present invention;

[0034] Figure 4 Schematic diagram of the signal intensity curve (driving voltage) of the sensor provided by the embodiment of the present invention;

[0035] Figures 5A - 5C Schematic diagram of the relative displacement between the display content and the sensor provided by the embodiment of the present invention;

[0036] Figure 6 Schematic diagram of the signal intensity curve (display delay) of the sensor provided by the embodiment of the present invention;

[0037] Figure 7 Schematic diagram of the scanning trajectory and the sensor provided by the embodiment of the present invention;

[0038] Figure 8 Schematic diagram of the signal intensity curve (phase delay) of the sensor provided by the embodiment of the present invention;

[0039] Figure 9A and Figure 9B Schematic diagram of the sensor located outside the image provided by the embodiment of the present invention;

[0040] Figure 10 Schematic diagram of the moving direction of the test pattern provided by the embodiment of the present invention. Detailed implementation manners

[0041] 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.

[0042] 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, the optical fiber scanning display device is taken as an example of the scanning display device, and the raster scanning mode is taken as an example for description.

[0043] Please refer to Figure 1 , Figure 1 Schematic diagram of the structure of the scanning trajectory detection device provided by the 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 of it passes through the waveguide lens D and enters the sensor C to realize the detection of the scanning trajectory, and then realize the detection of the swing amplitude.

[0044] Sensor C can be a single-point light sensor, which 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 where the center of the light spot sweeps across the sensor area can be recorded by the sensor, generating a signal intensity curve, and the center position of the peak of the signal intensity curve is the position of the center of the light spot. Further, the moment corresponding to the center position of the peak of the signal intensity curve is taken as the moment when the light spot sweeps across the sensor.

[0045] In projection image display, the center of the light spot energy is taken as the geometric center of the light spot. The light spot is not well focused and imaged, and the position of the center of its energy distribution remains unchanged compared with the position 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.

[0046] In another possible implementation, between the scanning device A and the sensor C, specific optical structures such as lenses and micropores can also be used to optically focus the light emitted by the scanner on the photosensitive surface of the sensor to achieve the detection of the light energy distribution.

[0047] 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 sweep across each sensor.

[0048] 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 along the horizontal direction (x direction), and the slow axis scans along the vertical direction (y direction).

[0049] As Figure 2 shown, when the test pattern in the test image is a straight line, the position of the center of the line can be determined by detecting the signal intensity curve through 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 along the horizontal direction.

[0050] 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 across the center position of the sensor is determined.

[0051] When the test image is displayed as a vertical line, by adjusting the display delay in the x direction or the driving phase delay of the fast axis for scanning, the sensor delay value when the center of the vertical line sweeps across the center position of the sensor can be determined.

[0052] When the test image is displayed as a horizontal line, adjust the display delay in the y direction or the slow axis drive phase delay for scanning to determine the sensor delay value when the center position of the horizontal line sweeps across the center position of the sensor.

[0053] To reduce system requirements, when detecting the horizontal delay, there is no need 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 drive phase and display delay.

[0054] Through the above method, the measurement and calibration of the scanning trajectory can be achieved. Next, the swing detection method in the embodiments of the present invention will be described in combination with specific embodiments.

[0055] As Figure 3 shown, the swing detection method in the embodiments of the present invention includes the following steps.

[0056] Step 301, control the scanning display device to output a test image;

[0057] Among them, the test image includes a test pattern with a specific shape, and the position of the test pattern in the test image corresponds to the position of the sensor in the scanning area of the scanning device.

[0058] Step 302, during the scanning process, gradually increase the drive voltage applied to the scanning device, detect the moment when the light spot corresponding to the test pattern output by the scanning device sweeps across the sensor through the sensor, and record the current drive voltage corresponding to the current moment.

[0059] Step 303, determine that the swing of the scanning trajectory at the current drive voltage is the target swing corresponding to the position where the sensor is located.

[0060] In the embodiments of the present invention, the target swing is obtained according to the set position of the sensor. When the light spot corresponding to the test image sweeps across the sensor, it means that the fiber swing reaches the target swing, so as to realize fiber swing detection through a single sensor.

[0061] In the embodiments of the present invention, the scanning display device includes a sensor, and the sensor is located at the edge of the scanning area of the scanning device. Placing the sensor in the edge area of the scanning area, the higher the accuracy is closer to the edge.

[0062] In the embodiments of the present invention, the test pattern in the test image is a vertical line. A vertical line is displayed at the corresponding phase position of the sensor, and the drive voltage of the scanning device is gradually increased, so that the fast axis swing gradually increases from 0, and then drives the fiber swing fixed on the scanning device to gradually increase, as Figure 4As shown, at the driving voltage corresponding to the center of the curve peak of the signal intensity curve detected by the sensor, the swing amplitude of the scanning trajectory is the target swing amplitude, and the current driving voltage corresponding to the current moment is recorded.

[0063] Within a small range, the fiber swing amplitude and the driving voltage of the scanning device can be approximately regarded as a linear relationship. Assume that the current driving voltage is V 1 , the target swing amplitude is A 1 , the rated swing amplitude is A 0 , since the sensor is located at the edge of the scanning area, A 0 is slightly larger than A 1 , therefore, it can be known that when the fiber swing amplitude is to reach the rated swing amplitude A 0 , the rated driving voltage V 0 is

[0064]

[0065] Through the above functional relationship, the driving voltage required by the scanning device when the fiber swing amplitude is the rated swing amplitude A 0 can be calculated. This calculation method can eliminate the influence of the aging of the device's own performance. By adjusting the driving voltage, the long-term stability of the rated swing amplitude of the fiber can be ensured.

[0066] In the embodiment of the present invention, during the usage period of the device, the offset of the image center position will cause amplitude detection errors, and a sensor can be added to eliminate the errors.

[0067] In a possible implementation manner, a sensor can be placed at the center position, and then, the center offset can be eliminated through the phase delay correction method.

[0068] In the scanning display, the display content needs to modulate the light source according to the scanning trajectory in time sequence to complete the 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 the scanning display, since there is a 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 the image display. In practical applications, the fast axis usually requires an additional correction drive signal in the y direction to ensure that the scanning trajectory is closed and not elliptical. If the driving phase is adjusted, the correction phase needs to be synchronously adjusted to ensure that the fast-axis trajectory is closed.

[0069] As Figures 5A - 5C 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, thereby eliminating the offset of the scanning image center position and keeping the scanning image center position unchanged.

[0070] During the scanning process, the sensor signal intensity values are recorded in real time, and a curve can be obtained. As Figure 6 shown, the delay t1 corresponding to the center position of the curve peak is the display delay or driving phase when the center of the vertical line in the test image is aligned with the center of the sensor. Since the sensor position 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.

[0071] In the embodiments of the present invention, for the convenience of description, as Figure 7 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, as shown in the following figure. The 0-pi segment trajectory is for odd rows, and the pi-2pi segment trajectory is for even rows.

[0072] Since the sensor is set at the center position of the image, as Figure 7 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 displayed in odd rows. That is, the vertical line is displayed at the point of phase pi / 4. Adjust the driving signal phase delay (if the correction voltage is not 0, the correction voltage phase needs to be adjusted synchronously) so that the vertical line sweeps across the sensor, and a curve as Figure 8 shown is obtained. Then, calculate the center position of the curve to obtain the t1 value. It can be concluded that when the fast-axis driving 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.

[0073] In the above solution, it is also possible not to adjust the driving voltage phase delay, and it is also feasible to adjust the display delay.

[0074] In the second possible implementation manner, a sensor is set outside the scanning area. As Figure 9A and Figure 9B shown, the sensor is located on the left or right side outside the image, ensuring that the sensor is outside the image and can receive the light intensity signal. When adjusting the fast-axis driving phase, the test pattern in the test image is a vertical line of the same width or a rectangular area. Adjust the delay. When the vertical line is at one edge of the sensor, the signal intensity received by the sensor is the largest. Within a certain range, the detection result is not affected by the relative position between the sensor and the image, nor by the fast-axis swing amplitude and the slow-axis swing amplitude. Therefore, this method has stronger parameter redundancy and directly completes the correction of the phase delay using a single sensor.

[0075] During the specific implementation process, as Figure 10As shown, set the test pattern in the test image to a vertical line or a rectangular area. At the time of factory shipment, adjust the image delay correctly so that the odd and even line images coincide, and record the current image delay d1. Then, adjust the delay in one direction so that the image moves to the edge of the sensor and then turns back. Record the sensor signal values, and use methods such as filtering and curve fitting to eliminate noise and reduce measurement errors. Find the delay value d2 corresponding to the center axis of the curve peak, and record the standard delay difference Δd = d2 - d1. The factory calibration is completed.

[0076] During subsequent use, when the scanner delay needs to be corrected, within the range of d1 - s and d1 + s, adjust the delay value in one direction so that the image moves to the edge of the sensor and then turns back. In the embodiments 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, 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 photosensitive surface of the sensor.

[0077] Record the sensor signal values, and use methods such as filtering and curve fitting to eliminate noise and reduce measurement errors. Find the delay value d2' corresponding to the center axis of the curve peak. Calculate d1' = d2' - Δd, where d1' is the drive delay corresponding to the coincidence of the current odd and even line images.

[0078] In the embodiments of the present invention, during the operation of the scanning display device, phase delay correction can be directly performed, or before performing phase delay correction, it can be detected whether the center position of the scanning display device has shifted. In the specific implementation process, add a sensor at a non - center position, and measure the drive voltage required when the swing amplitude reaches the rated swing amplitude respectively according to the swing amplitude detection method in the above - mentioned embodiments. If the two calculated drive voltages are the same, it indicates that the image center position has not shifted. If the two calculated drive voltages are different, it indicates that the image center position has shifted. Then, eliminate the center shift through the phase delay correction method in the above - mentioned embodiments.

[0079] 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 swing amplitude detection method are implemented.

[0080] All features disclosed in this specification, or all steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

[0081] Any feature disclosed in this specification (including any additional claims, abstract and drawings), unless specifically recited, may be replaced by other equivalent or alternative features with similar purposes. That is, unless specifically recited, each feature is only an example of a series of equivalent or similar features.

[0082] 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 to any step of any new method or process disclosed or any new combination.

Claims

1. A swing amplitude detection method, characterized in that, it is applied to a scanning display device, and the scanning display device includes a scanning display component and a sensor; the scanning display component includes a light source and a scanning component, and the scanning component is used to scan and emit the light emitted by the light source; the method includes: Controlling the scanning display component to output a test image; wherein, the test image includes a test pattern with a specific shape, and the position of the test pattern in the test image corresponds to the position of the sensor in the scanning area of the scanning component; During the scanning process, gradually increase the driving voltage applied to the scanning component, detect the moment when the light spot corresponding to the test pattern output by the scanning component scans across the sensor through the sensor, and record the current driving voltage corresponding to the current moment; Determine that the swing amplitude of the scanning trajectory under the current driving voltage is the target swing amplitude corresponding to the position where the sensor is located.

2. The method according to claim 1, characterized in that, the scanning display device includes a sensor, and the sensor is located at the edge of the scanning area of the scanning component.

3. The method according to claim 1, characterized in that, the method further includes: Calculating the rated voltage required for the optical fiber to reach the rated swing amplitude according to the target swing amplitude, the rated swing amplitude of the optical fiber, the current driving voltage and a set functional relationship.

4. The method according to claim 3, characterized in that, the scanning display device includes two sensors, which are respectively located at different positions on the edge of the scanning area of the scanning component; the method further includes: Based on the two sensors, respectively calculate the rated voltage required for the optical fiber to reach the rated swing amplitude; If the rated voltages obtained by the two calculations are different, it indicates that the central position of the scanning image of the scanning component is shifted.

5. The method according to claim 2 or 4, characterized in that, the scanning display device further includes a sensor arranged at the central position of the scanning area; the method further includes: Controlling the scanning display component to output a test image, and the test image includes a test pattern with a specific shape; Recording the moment when the light spot corresponding to the test pattern output by the scanning display component scans across the central position sensor; Calculating the image delay between the scanning trajectory of the scanning display component and the test image according to the moment when the light spot scans across the central position sensor; Adjusting the driving delay of the scanning display component according to the image delay so that the scanning trajectory of the scanning display component and the display content are synchronized, and eliminating the shift of the central position of the scanning image.

6. The method according to claim 2 or 4, characterized in that, the scanning display device further includes a sensor arranged outside the scanning area; a standard delay difference is stored in the scanning display device, and the method further includes: Controlling the scanning display component to output a test image, and the test image includes a test pattern with a specific shape; Adjusting the driving delay of the scanning display component and recording the current delay corresponding to the maximum signal intensity detected by the sensor outside the scanning area; Calculate the difference between the current delay and the standard delay difference, and adjust the driving delay of the scanning display device based on the difference, so that the scanning trajectory of the scanning display device is synchronized with the display content, and the offset of the center position of the scanned image is eliminated.

7. 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 described in any one of claims 1-6 are implemented.

8. 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 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 a processor, the steps of the method described in any one of claims 1-6 are implemented.

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