A swing detection method, an optical fiber scanning device and a readable storage medium

Abstract

The application discloses a swing detection method, an optical fiber scanning device and a readable storage medium. The swing detection method comprises the following steps: detecting a feedback signal for representing whether an optical fiber contacts a flexible limiting structure during vibration of an actuator; judging whether the optical fiber contacts the flexible limiting structure according to a state of the feedback signal; and determining that a current swing of the optical fiber is a set swing when the optical fiber can contact the flexible limiting structure when the judgment result is yes. In the above scheme, the state of the feedback signal reflects the contact state between the optical fiber and the flexible limiting structure, so that whether the current swing of the optical fiber reaches the set swing is determined. This scheme does not need an external sensor, does not increase the system volume, power consumption and cost, and can eliminate the influence of the performance aging of the device itself and accurately detect the swing of the optical fiber.

Description

Technical Field

[0001] This invention relates to the field of projection display, and more particularly to a swing amplitude detection method, a fiber optic scanning device, and a readable storage medium. Background Technology

[0002] The imaging principle of fiber scanning display (FSD) is that an actuator drives an optical fiber to move along a predetermined two-dimensional scanning trajectory, and modulates the light output from the light source corresponding to each pixel of the image to be displayed. Then, the light corresponding to each pixel of the image to be displayed is projected onto the 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 fiber optic swing is crucial for maintaining constant image size, especially in image stitching and binocular fusion applications. However, due to device aging and changes in environmental conditions, fiber optic swing may still change even if the drive signal of the fiber optic scanning device remains constant.

[0004] To maintain image stability, feedback control is needed for fiber optic swing. Currently, a common approach is to use external sensors to detect vibrations in the actuator or fiber optic cable, or to use photoelectric devices to detect the image path, thereby achieving feedback control. However, using external sensors requires additional detection circuitry, increasing system complexity, size, power consumption, and cost. Summary of the Invention

[0005] The purpose of this invention is to provide a swing amplitude detection method, an optical fiber scanning device, and a readable storage medium to solve the technical problem that existing feedback control schemes require additional sensors and detection circuits, which increases system size, power consumption, and cost.

[0006] To achieve the above-mentioned objective, the first aspect of the present invention provides a swing amplitude detection method applied in an optical fiber scanning device, wherein the optical fiber scanning device includes an actuator and an optical fiber fixed on the actuator; at least one side of the optical fiber is provided with a flexible limiting structure, the flexible limiting structure being located on the vibration plane of the optical fiber;

[0007] During the vibration of the actuator, a feedback signal is detected to characterize whether the optical fiber contacts the flexible limiting structure;

[0008] Based on the state of the feedback signal, it is determined whether the optical fiber is in contact with the flexible limiting structure;

[0009] If the judgment result is yes, the current fiber swing amplitude is determined to be the set swing amplitude when the fiber can contact the flexible limiting structure.

[0010] Optionally, the method further includes:

[0011] When the determination result is yes, record the current driving voltage applied to the actuator;

[0012] The rated drive voltage of the actuator is calculated based on the set swing amplitude, the rated swing amplitude of the optical fiber, the current drive voltage, and the set functional relationship.

[0013] Optionally, the defined functional relationship is as follows:

[0014] Where V0 is the rated driving voltage, A max The set swing amplitude is A0, the rated swing amplitude of the optical fiber is V. max The current driving voltage is [value].

[0015] Optionally, during the vibration of the actuator, detecting a feedback signal characterizing whether the optical fiber contacts the flexible limiting structure includes:

[0016] During the vibration of the actuator, the driving voltage applied to the actuator is gradually increased;

[0017] During the process of increasing the driving voltage, the feedback signal is acquired through the driving circuit of the actuator or the fiber optic scanning device.

[0018] Optionally, the feedback signal is acquired through the drive circuit of the fiber optic scanning device, including:

[0019] In the drive circuit of the fiber optic scanning device, the voltage or current signal of the actuator is collected as a feedback signal.

[0020] Optionally, determining whether the optical fiber is in contact with the flexible limiting structure based on the state of the feedback signal includes:

[0021] Determine whether the feedback signal is distorted. If the feedback signal is distorted, then determine that the optical fiber is in contact with the flexible limiting structure.

[0022] Optionally, the set swing amplitude is slightly larger than the rated swing amplitude of the optical fiber.

[0023] A second aspect of the present invention provides an optical fiber scanning device, comprising:

[0024] An actuator and an optical fiber fixed to the actuator;

[0025] A flexible limiting structure is provided on at least one side of the optical fiber, and the flexible limiting structure is located on the vibration plane of the optical fiber.

[0026] A controller is configured to detect a feedback signal characterizing whether the optical fiber contacts the flexible limiting structure during the vibration of the actuator.

[0027] Based on the state of the feedback signal, it is determined whether the optical fiber is in contact with the flexible limiting structure. If the determination result is yes, the current optical fiber swing amplitude is determined to be the set swing amplitude when the optical fiber can contact the flexible limiting structure.

[0028] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0029] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0030] In this embodiment of the invention, at least one side of the optical fiber is provided with a flexible limiting structure, which is located on the vibration plane of the optical fiber. When the actuator vibrates under a driving voltage greater than the rated voltage, the optical fiber can contact the flexible limiting structure. When the optical fiber can contact the flexible limiting structure, the state of the feedback signal changes, and the current swing amplitude of the optical fiber can be determined by the state of the feedback signal. This embodiment of the invention does not require external sensors, does not increase system size, power consumption, or cost, and can eliminate the effects of device aging, accurately detecting the optical fiber swing amplitude. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0032] Figure 1 A top view of the fiber optic display device provided in an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of fiber optic swing provided in an embodiment of the present invention;

[0034] Figure 3 This is a schematic flowchart of the swing amplitude detection method provided in an embodiment of the present invention;

[0035] Figure 4A A schematic diagram illustrating the detection of fiber optic swing in the fast axis direction according to an embodiment of the present invention;

[0036] Figure 4B for Figure 4ASide view of the structure shown;

[0037] Figure 5 A schematic diagram of a piezoelectric feedback signal detection circuit provided in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the control flow of the fiber optic scanning device provided in an embodiment of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] In this embodiment of the invention, the structure of the fiber optic scanning device is first described. Please refer to... Figure 1 , Figure 1 This is a top view of the fiber optic scanning device in an embodiment of the present invention, including an actuator 10 and an optical fiber 20 fixed to the actuator 10. When the actuator 10 vibrates, it causes the optical fiber 20 to swing in space. Regarding the arrangement of the optical fiber 20, it can be fixed to the surface of the actuator 10, it can extend from the middle of the actuator 10, or other arrangements can be used. The portion of the optical fiber 20 extending beyond the end of the actuator 10 forms a cantilever. Generally, the operating frequency of the actuator 10 is selected near the resonant frequency of the optical fiber 20, so that the optical fiber 20 can achieve a large swing amplitude when vibrating.

[0041] A flexible limiting structure 30 is provided on at least one side of the optical fiber 20. The flexible limiting structure 30 is located on the vibration plane of the optical fiber 20, and its position is set between the optical fiber swing amplitude position (i.e., rated swing amplitude) and the optical fiber limit swing amplitude position when the scanning display device is working normally. When the actuator 10 vibrates under a driving voltage greater than the rated voltage, the optical fiber 20 can contact the flexible limiting structure 30, and the swing amplitude of the optical fiber 20 reaches the set swing amplitude, such as... Figure 2 As shown.

[0042] like Figure 3 The diagram shown is a flowchart of the swing amplitude detection method provided in an embodiment of the present invention, which includes the following steps.

[0043] Step 301: During the vibration of the actuator, a feedback signal is detected to characterize whether the optical fiber contacts the flexible limiting structure.

[0044] Step 302: Determine whether the optical fiber is in contact with the flexible limiting structure based on the state of the feedback signal.

[0045] Step 303: If the judgment result is yes, determine the current fiber swing amplitude as the set swing amplitude when the fiber can contact the flexible limiting structure.

[0046] In the above scheme, the contact state between the optical fiber 20 and the flexible limiting structure 30 is reflected by the status of the feedback signal, and it is determined whether the current swing amplitude of the optical fiber 20 has reached the set swing amplitude. The scheme in this embodiment of the invention does not require external sensors, does not increase the system volume, power consumption and cost, and can eliminate the influence of device performance aging, and accurately detect the swing amplitude of the optical fiber.

[0047] In this embodiment of the invention, the flexible limiting structure 30 can be provided on one side or both sides. The length of the flexible limiting structure 30 is less than the cantilever length of the optical fiber 20 to prevent the end face of the optical fiber from contacting the flexible limiting structure 30 and damaging the end face of the optical fiber or the lens on the end face of the optical fiber. The hardness of the contact area between the flexible limiting structure 30 and the optical fiber 20 is much less than that of the optical fiber, and there are no sharp structures on the flexible limiting structure 30 to prevent damage to the optical fiber 20 when in contact with it.

[0048] When detecting the swing amplitude of the optical fiber 20, a driving voltage slightly greater than the rated voltage of the scanning display device is used, allowing the middle part of the optical fiber 20 to contact the flexible limiting structure 30. The resonant frequency of the cantilever end of the flexible limiting structure 30 is far from the operating frequency of the scanning display device, thus avoiding resonance.

[0049] In this embodiment of the invention, the flexible limiting structure 30 can be fixed to the end face of the actuator 10, or it can be disposed on the base of the actuator 10 or on the encapsulation housing. The invention does not limit this.

[0050] When the flexible limiting structure 30 is fixed to the end face of the actuator 10, and the actuator 10 bends, the flexible limiting structure 30 moves together with the actuator 10 and the optical fiber 20, preventing the optical fiber 20 from hitting the flexible limiting structure 30 and breaking the end face of the optical fiber when the optical fiber scanning device falls. At the same time, since the flexible limiting structure 30 is located outside the optical fiber 20, it can also act as a buffer during a fall, protecting the optical fiber 20.

[0051] Because the resonant frequency of the flexible limiting structure 30 is far from the operating frequency of the actuator 10, the flexible limiting structure 30 will not resonate when the actuator 10 vibrates. Under normal operating conditions, the fiber optic scanning device vibrates at its rated amplitude, and the fiber optic 20 will not contact the flexible limiting structure 30. When the fiber optic amplitude is slightly greater than the rated amplitude, the fiber optic 20 will contact the flexible limiting structure 30.

[0052] In this embodiment of the invention, it is assumed that the optical fiber 20 can vibrate in the X direction (horizontal direction) and the Y direction (vertical direction), and its scanning mode can be raster, Lissajous, or spiral scanning. Taking raster scanning as an example, the operating frequency in the X direction is much higher than the operating frequency in the Y direction; therefore, the X direction is also called the fast axis direction, and the Y direction is also called the slow axis direction. Figure 4A and Figure 4B As shown, Figure 4A A schematic diagram for detecting the fiber optic swing in the fast axis direction. Figure 4B This is a side view, in which a flexible limiting structure 30 is bonded to one side of the optical fiber 20. The flexible limiting structure 30 is located on the vibration plane of the optical fiber 20, that is, the XZ plane, where the Z direction represents the extension direction of the optical fiber 20.

[0053] Next, we will explain how to detect the fiber optic swing amplitude using the flexible limiting structure 30.

[0054] In this embodiment of the invention, the contact status between the optical fiber 20 and the flexible limiting structure 30 can be determined by detecting the piezoelectric feedback signal. For example, impedance analysis or LC resonant feedback methods can be used to detect the operating state of the response drive shaft. After the optical fiber 20 contacts the flexible limiting structure 30, the current signal or resonant voltage signal in the drive circuit of the optical fiber scanning device will show obvious abnormalities. Therefore, the contact status between the optical fiber 20 and the flexible limiting structure 30 can be determined by the feedback signal, thereby determining whether the optical fiber 20 has reached the set swing amplitude.

[0055] In one possible implementation, the driving voltage required for the actuator 10 to maintain the rated swing can be calculated based on the functional relationship between the set swing amplitude, the rated swing amplitude of the optical fiber 20, and the driving voltage. By adjusting the driving voltage, the swing amplitude of the optical fiber can be kept stably at the rated swing amplitude for a long period of time.

[0056] Assuming the rated swing of the optical fiber is A0, and the swing is A when the optical fiber just touches the limiting structure. max A max Slightly larger than A0. Where A0 and A... max These are preset values, which can be pre-stored in the fiber optic scanning device or in a device connected to the fiber optic scanning device.

[0057] The actuator 10 drives the optical fiber 20 to vibrate, and the driving voltage is gradually increased to gradually increase the swing amplitude of the optical fiber. During this process, the piezoelectric feedback signal is detected to check whether the optical fiber scanning device is vibrating normally.

[0058] Because the current signal or resonant voltage signal in the drive circuit of the fiber scanning device will become significantly abnormal after the fiber optic cable 20 comes into contact with the flexible limiting structure 30. Therefore, when the piezoelectric feedback signal reflects a significant vibration abnormality, the current fiber optic swing amplitude can be determined to be A.max Record the current fiber swing as A. max The current driving voltage at that time is V max Within a small range, the fiber swing and the scanner drive voltage can be approximated as having a linear relationship, since A max Slightly greater than A0, therefore, it can be determined that when the current fiber swing is A0, the driving voltage V0 is...

[0059]

[0060] The driving voltage required by actuator 10 when the fiber swing is the rated swing A0 can be calculated using the above functional relationship. This calculation method can eliminate the influence of device aging and ensure the long-term stability of the rated swing of the fiber by adjusting the driving voltage.

[0061] In this embodiment of the invention, the detection of piezoelectric feedback signal is explained using LC resonant feedback as an example.

[0062] like Figure 5 The diagram shows a schematic of the detection circuit for the piezoelectric feedback signal. The drive circuit includes a piezoelectric actuator C1, an inductor L1 connected in series with the piezoelectric actuator C1, and a voltage source V1. In this embodiment of the invention, the resonant terminal FB voltage signal is used as the piezoelectric feedback signal. When the fast axis is driven normally, the resonant terminal FB voltage signal in the fast axis drive circuit is a stable sine wave. However, when the optical fiber 20 contacts the flexible limiting structure 30, the vibration of the actuator 10 is disturbed, and the FB terminal voltage signal will be severely distorted. Therefore, it is possible to determine whether the optical fiber 20 is in contact with the flexible limiting structure 30 by detecting whether the FB terminal voltage signal is abnormal.

[0063] like Figure 6 The diagram shows the control flow of the fiber optic scanning device. During the operation of the fiber optic scanning device, the controller 60 controls the actuator 62 to vibrate through the drive module 61 and detects the piezoelectric feedback signal through the voltage detection module 63. Then, based on the detected piezoelectric feedback signal, it determines whether the fiber 20 is in contact with the flexible limiting structure 30. When the fiber 20 just contacts the flexible limiting structure 30, the driving voltage required for the fiber 20 to maintain its rated swing is further calculated. The feedback control process can be performed during the initialization of the fiber optic scanning device or during operation according to user instructions to ensure that the rated swing of the fiber 20 remains stable.

[0064] Based on the same inventive concept, this invention also provides an optical fiber scanning device. The structure and feedback control scheme of the optical fiber scanning device are as described in the foregoing embodiments, and will not be described in detail here.

[0065] In another exemplary embodiment, a computer-readable storage medium including program instructions is also provided, which, when executed by a processor, implement the steps of the swing detection method described above. 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 device to complete the swing detection method described above.

[0066] In another exemplary embodiment, a computer program product is also provided, the computer program product comprising a computer program executable by a programmable device, the computer program having a code portion for performing the swing detection method described above when executed by the programmable device.

[0067] In this embodiment of the invention, the scanning display technology based on fiber optic scanning devices can be applied to head-mounted AR (Augmented Reality) devices, head-mounted VR (Virtual Reality) devices, projection TVs, projectors, etc., and its applications are very wide.

[0068] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0069] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0070] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A method for detecting swing amplitude, characterized in that, The fiber optic scanning device includes an actuator and an optical fiber fixed on the actuator; at least one side of the optical fiber is provided with a flexible limiting structure, which is located on the vibration plane of the optical fiber. During the vibration of the actuator, the driving voltage applied to the actuator is gradually increased; During the process of increasing the driving voltage, a feedback signal is acquired through the driving circuit of the actuator or the fiber scanning device. The feedback signal is used to characterize whether the fiber contacts the flexible limiting structure. Based on the state of the feedback signal, it is determined whether the optical fiber is in contact with the flexible limiting structure; When the judgment result is yes, the current fiber swing amplitude is determined to be the set swing amplitude when the fiber can contact the flexible limiting structure. And record the current drive voltage applied to the actuator; The rated driving voltage of the actuator is calculated based on the set swing amplitude, the rated swing amplitude of the optical fiber, the current driving voltage, and the set functional relationship. Wherein, the defined functional relationship is: ; The rated drive voltage, For the set swing amplitude, The rated swing amplitude of the optical fiber, The current driving voltage is [value].

2. The method as described in claim 1, characterized in that, The feedback signal is acquired through the drive circuit of the fiber optic scanning device, including: In the drive circuit of the fiber optic scanning device, the voltage or current signal of the actuator is collected as the feedback signal.

3. The method as described in claim 2, characterized in that, Determining whether the optical fiber is in contact with the flexible limiting structure based on the state of the feedback signal includes: Determine whether the feedback signal is distorted. If the feedback signal is distorted, then determine that the optical fiber is in contact with the flexible limiting structure.

4. The method as described in claim 1, characterized in that, The set swing amplitude is slightly larger than the rated swing amplitude of the optical fiber.

5. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the steps of the method described in any one of claims 1-4.

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