A small size lissajous fiber scanner

Abstract

This application discloses a small-sized Lissajous fiber optic scanner, including a base, a cylindrical piezoelectric actuator, a sheet-like piezoelectric actuator, and an optical fiber. The cylindrical piezoelectric actuator has a first through-hole extending axially through itself, and the base has a second through-hole connecting the first through-hole. The sheet-like piezoelectric actuator is disposed within the first through-hole, and its rear end is fixedly connected to the free end of the cylindrical piezoelectric actuator. The cylindrical piezoelectric actuator, the sheet-like piezoelectric actuator, and the optical fiber constitute a scanner cantilever. The sheet-like piezoelectric actuator ensures that the natural frequency of the scanner cantilever in the horizontal direction is greater than its natural frequency of the same order in the vertical direction. This application utilizes the adjustment of the shape and / or dimensional parameters of the sheet-like piezoelectric actuator to ensure good scanning performance. The cylindrical piezoelectric actuator is a regularly shaped, rotationally symmetrical piezoelectric actuator, which is easy to manufacture, has easily controllable manufacturing errors, and a high yield rate.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 2024119612022, filed with the Chinese Patent Office on December 30, 2024, entitled "A Small-Sized Lissajous Fiber Optic Scanner", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of fiber optic scanner structure technology, and in particular to a small-sized Lissajous fiber optic scanner. Background Technology

[0003] A fiber optic scanner is a display technology that uses a scanning driver to control the oscillation of an optical fiber while simultaneously emitting light. It is primarily used in fiber optic scanning display technology, fiber optic scanning endoscopy technology, and fiber optic scanning radar. When applied to image display, fiber optic scanners produce images with sharp, saturated colors, high contrast, high brightness, and a very small structural size.

[0004] Fiber optic scanners utilize the principle of mechanical resonance to enable a large scanning range for the fiber optic cantilever. Scanning methods of the scanning driver can be categorized into helical scanning, grid scanning, and Lissajous scanning. Lissajous scanning micro-piezoelectric scanning devices typically have driving sections in two directions, driving the scanning device to vibrate simultaneously in both directions. In Lissajous scanning, the closer the driving frequencies in the two directions, the closer the uniformity (density) of the scanning grid in both directions. Theoretically, the closer the driving frequencies in these two directions, the better. However, the closer the natural frequencies used by the scanner in the two directions, the more pronounced the vibration coupling effect becomes, which degrades the scanning trajectory, causing uncontrolled components in the scanning trajectory and resulting in image distortion that is difficult to completely eliminate through post-processing. Therefore, the natural frequencies used by the Lissajous scanner in the two directions should ideally have a precise difference range, avoiding both excessively small differences that cause coupling effects and excessively large differences that lead to unsatisfactory uniformity.

[0005] The manufacturing of Lissajous scanners, which utilize the inherent frequencies in both directions with precise differences, requires extremely high processing accuracy, making it difficult to guarantee both the cost of processing equipment and the yield rate. Summary of the Invention

[0006] This application provides a small-sized Lissajous fiber scanner, which not only reduces the processing difficulty and improves the processing yield, but also integrates the scanner structure, reducing the volume and size of the fiber scanner.

[0007] To achieve the aforementioned objectives, this application provides a small-sized Lissajous fiber scanner, comprising a base, a cylindrical piezoelectric actuator, a sheet-like piezoelectric actuator, and an optical fiber, wherein the cylindrical piezoelectric actuator is a one-dimensional scanning piezoelectric actuator.

[0008] The fixed end of the cylindrical piezoelectric actuator is fixedly connected to the base so as to be supported by the base. The cylindrical piezoelectric actuator has a first through hole that penetrates through itself along the axial direction. The base has a second through hole that connects to the first through hole.

[0009] The free end of the cylindrical piezoelectric actuator vibrates along a first direction. Taking the free end of the cylindrical piezoelectric actuator as the rear end and the fixed end of the cylindrical piezoelectric actuator as the front end, with the first direction as the left-right direction,...

[0010] A sheet-shaped piezoelectric actuator is disposed in the first through hole. The sheet-shaped piezoelectric actuator is arranged in a direction parallel to the horizontal plane. Its rear end is fixedly connected to the free end of the cylindrical piezoelectric actuator. The front end of the sheet-shaped piezoelectric actuator is located in the first through hole or in the second through hole. Its length can be set according to the actual working conditions and is not limited. The front end of the sheet-shaped piezoelectric actuator vibrates in the vertical direction. The optical fiber is fixedly disposed at the front end of the sheet-shaped piezoelectric actuator in a cantilever support manner.

[0011] The front end of the sheet-shaped piezoelectric actuator vibrates in two dimensions within the first through hole or the first and second through holes under the combined drive of the cylindrical piezoelectric actuator and itself. The diameters of the first and second through holes are set to be no less than the swing range of the sheet-shaped piezoelectric actuator and the optical fiber, meaning that the sheet-shaped piezoelectric actuator and the optical fiber will not contact the wall of the first or second through hole of the cylindrical piezoelectric actuator during scanning.

[0012] A cylindrical piezoelectric actuator, a sheet piezoelectric actuator, and an optical fiber constitute a scanner cantilever. The sheet piezoelectric actuator makes the natural frequency of the scanner cantilever in the horizontal direction greater than its natural frequency of the same order in the vertical direction, and makes a difference between a certain natural frequency of the scanner cantilever in the vertical direction that is closest to its natural frequency of order V in the horizontal direction and the natural frequency of order V in the horizontal direction, where V is an integer greater than or equal to 1.

[0013] The scanner cantilever has first-order, second-order, third-order, ... N-order natural frequencies in the vertical direction. Among them, there is a certain natural frequency (e.g., U-order, where U is an integer greater than or equal to two) that is closest to the V-order natural frequency of the scanner cantilever in the horizontal direction (V is less than U). In Lissajous scanning, the closer the driving frequencies in the two directions are, the closer the uniformity (density) of the scanning grid in the two directions will be, and the more points can be taken. Theoretically, the closer the driving frequencies in the two directions are, the better. However, the closer the natural frequencies used by the scanner cantilever in the two directions are, the more obvious the coupling effect will be. Therefore, this application utilizes the shape structure and / or size parameters of the sheet piezoelectric actuator to ensure that the natural frequencies of the scanner cantilever used in the two directions are simultaneously close enough to ensure good scanning effect and a uniform and dense scanning grid, while also having a sufficient difference so that the vibration of the scanner cantilever in the two directions will not produce coupling.

[0014] Therefore, the difference satisfies the requirement that when the cylindrical piezoelectric actuator performs Lissajous scanning under the drive signal, the vibration of the scanner cantilever in the horizontal direction and in the vertical direction will not be coupled.

[0015] Generally, the difference ranges from 10Hz to 12kHz. More preferably, the difference ranges from 1kHz to 10kHz. Specifically, the difference is selected based on the V-order natural frequency of the scanner arm in the horizontal direction. The difference is sufficient to ensure that the scanner arm has sufficient amplitude when the piezoelectric actuator performs Lissajous scanning under drive, and that the vibrations of the scanner arm in the horizontal and vertical directions do not couple. For those skilled in the art, selecting values ​​based on the above description is a conventional technique in the field.

[0016] The sheet-shaped piezoelectric actuator and the cylindrical piezoelectric actuator have overlapping portions in the front-to-back direction. The sheet-shaped piezoelectric actuator and the fiber cantilever can be almost completely hidden in the through holes of the cylindrical piezoelectric actuator and the base, which greatly reduces the length of the fiber scanner in the front-to-back direction and reduces the size of the scanner.

[0017] Preferably, the natural frequencies of the cylindrical piezoelectric actuator in the lateral direction and the same-order natural frequencies in the vertical direction are the same or similar. The cylindrical piezoelectric actuator referred to here is the cylindrical piezoelectric actuator itself, excluding sheet-like piezoelectric actuators and other components such as optical fibers. Cylindrical piezoelectric actuators meeting these requirements are regularly shaped, rotationally symmetrical piezoelectric actuators, with low manufacturing difficulty, easily controlled manufacturing errors, and high yield rates. Examples include round tube piezoelectric actuators and square tube piezoelectric actuators.

[0018] Optionally, the sheet-like piezoelectric actuator is a single-piezoelectric actuator or a dual-piezoelectric actuator. The sheet-like piezoelectric actuator is also a conventional actuator, with low manufacturing difficulty. This application, by combining two easily manufactured components, obtains a scanner suitable for Lissajous scanning and with guaranteed anti-coupling effect, which is less difficult to manufacture and has a higher yield rate compared to existing Lissajous scanners.

[0019] The optical fiber is fixedly mounted on the upper or lower surface of the sheet-like piezoelectric actuator, or disposed inside the sheet-like piezoelectric actuator, using a cantilever support method. The cantilever support refers to the portion of the optical fiber extending beyond the front end of the sheet-like piezoelectric actuator forming an optical fiber cantilever, with the portion of the optical fiber located behind the cantilever fixedly connected to the sheet-like piezoelectric actuator. In one embodiment where the optical fiber is disposed inside the sheet-like piezoelectric actuator, the sheet-like piezoelectric actuator body has a mounting hole for accommodating the optical fiber, and the optical fiber is fixedly mounted within the mounting hole using a cantilever support method.

[0020] One or more technical solutions in this application have at least the following technical effects or advantages:

[0021] This application utilizes the shape and / or dimensional parameters of the sheet piezoelectric actuator to ensure that the natural frequencies of the scanner cantilever in both directions are sufficiently close to guarantee good scanning results and have a uniform and dense scanning grid, while also having sufficient difference to prevent coupling of the scanner cantilever's vibrations in both directions.

[0022] Since the natural frequencies of the cylindrical piezoelectric actuator in the lateral direction and in the vertical direction are the same or similar, the cylindrical piezoelectric actuator mentioned here refers to the first piezoelectric actuator itself, excluding sheet-like piezoelectric actuators and other components such as optical fibers. Cylindrical piezoelectric actuators that meet these requirements are regularly shaped, rotationally symmetrical piezoelectric actuators, with low manufacturing difficulty, easily controlled manufacturing errors, and high yield.

[0023] The sheet-shaped piezoelectric actuator and the cylindrical piezoelectric actuator have overlapping portions in the front-to-back direction. The sheet-shaped piezoelectric actuator and the fiber cantilever can be almost completely hidden in the through holes of the cylindrical piezoelectric actuator and the base, which greatly reduces the length of the fiber scanner in the front-to-back direction and reduces the size of the scanner. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of this application;

[0025] Figure 2 for Figure 1 A schematic diagram of the structure after removing the base;

[0026] Figure 3 This is a schematic diagram of the structure of a sheet-like piezoelectric actuator;

[0027] Figure 4 This is a schematic diagram of a cylindrical piezoelectric actuator.

[0028] Figure 5 This is a schematic diagram of a square-shaped piezoelectric actuator. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0030] like Figure 1 , Figure 2 , Figure 3 As shown, a small-sized Lissajous fiber scanner includes a base 400, a cylindrical piezoelectric actuator 100, a sheet-like piezoelectric actuator 200, and an optical fiber 300. The cylindrical piezoelectric actuator 100 is a one-dimensional scanning piezoelectric actuator.

[0031] The fixed end of the cylindrical piezoelectric actuator 100 is fixedly connected to the base 400 and is supported by the base 400. The cylindrical piezoelectric actuator 100 has a first through hole 101 that extends through itself along the axial direction. The base 400 has a second through hole 401 that communicates with the first through hole 101.

[0032] The free end of the cylindrical piezoelectric actuator 100 vibrates along a first direction. Taking the free end of the cylindrical piezoelectric actuator 100 as the rear end and the fixed end of the cylindrical piezoelectric actuator 100 as the front end, with the first direction as the left-right direction, the natural frequency of the cylindrical piezoelectric actuator 100 in the left-right direction is the same as or similar to its natural frequency in the vertical direction.

[0033] A sheet-shaped piezoelectric actuator 200 is disposed in the first through hole 101. The sheet-shaped piezoelectric actuator 200 is disposed in a direction parallel to the horizontal plane. Its rear end is fixedly connected to the free end of the cylindrical piezoelectric actuator 100. The front end of the sheet-shaped piezoelectric actuator 200 is located in the first through hole 101 or in the second through hole 401. Its length can be set according to the actual working conditions and is not limited. The front end of the sheet-shaped piezoelectric actuator 200 vibrates in the vertical direction. The optical fiber 300 is fixedly disposed at the front end of the sheet-shaped piezoelectric actuator 200 in a cantilever support manner.

[0034] The front end of the sheet-like piezoelectric actuator 200 vibrates in two dimensions within the first through hole 101 or the first through hole 101 and the second through hole 401, driven by the cylindrical piezoelectric actuator 100 and itself. The diameters of the first through hole 101 and the second through hole 401 are set to be no less than the swing range of the sheet-like piezoelectric actuator 200 and the optical fiber 300, that is, the sheet-like piezoelectric actuator 200 and the optical fiber 300 will not contact the wall of the first through hole 101 or the wall of the second through hole 401 of the cylindrical piezoelectric actuator 100 during the scanning process.

[0035] The cylindrical piezoelectric actuator 100, the sheet piezoelectric actuator 200, and the optical fiber 300 constitute a scanner cantilever. The sheet piezoelectric actuator 200 makes the natural frequency of the scanner cantilever in the horizontal direction greater than its natural frequency of the same order in the vertical direction, and makes a difference between a certain natural frequency of the scanner cantilever in the vertical direction that is closest to its natural frequency of V in the horizontal direction and the natural frequency of V in the horizontal direction, where V is an integer greater than or equal to 1.

[0036] The scanner cantilever has first-order, second-order, third-order, ... N-order natural frequencies in the vertical direction. Among them, there is a certain natural frequency (e.g., U-order, where U is an integer greater than or equal to two) that is closest to the V-order natural frequency of the scanner cantilever in the horizontal direction (V is less than U). In Lissajous scanning, the closer the driving frequencies in the two directions are, the closer the uniformity (density) of the scanning grid in the two directions will be, and the more points can be taken. Theoretically, the closer the driving frequencies in the two directions are, the better. However, the closer the natural frequencies used by the scanner cantilever in the two directions are, the more obvious the coupling effect will be. Therefore, this application uses the shape structure and / or size parameters of the sheet piezoelectric actuator 200 to make the natural frequencies of the scanner cantilever used in the two directions both close enough to ensure good scanning effect and have a uniform and dense scanning grid, and have enough difference so that the vibration of the scanner cantilever in the two directions will not produce coupling.

[0037] Therefore, the difference satisfies the requirement that when the cylindrical piezoelectric actuator 100 performs Lissajous scanning under the drive signal, the vibration of the scanner cantilever in the horizontal direction and in the vertical direction will not be coupled.

[0038] Generally, the difference ranges from 10Hz to 12kHz. More preferably, the difference ranges from 1kHz to 10kHz. Specifically, the difference is selected based on the V-order natural frequency of the scanner arm in the horizontal direction. The difference is sufficient to ensure that the scanner arm has sufficient amplitude when the piezoelectric actuator performs Lissajous scanning under drive, and that the vibrations of the scanner arm in the horizontal and vertical directions do not couple. For those skilled in the art, selecting values ​​based on the above description is a conventional technique in the field.

[0039] The sheet-shaped piezoelectric actuator 200 and the cylindrical piezoelectric actuator 100 have overlapping portions in the front-to-back direction. The sheet-shaped piezoelectric actuator 200 and the cantilever of the optical fiber 300 can be almost completely hidden in the through holes of the cylindrical piezoelectric actuator 100 and the base 400, which greatly reduces the length of the optical fiber scanner in the front-to-back direction and reduces the size of the scanner.

[0040] Preferably, the natural frequency of the cylindrical piezoelectric actuator 100 in the lateral direction is the same as or close to the natural frequency of the same order in the vertical direction. The cylindrical piezoelectric actuator 100 referred to here means the cylindrical piezoelectric actuator 100 itself, excluding the sheet-like piezoelectric actuator 200 and other components such as the optical fiber 300. A cylindrical piezoelectric actuator 100 that meets these requirements is a regularly shaped, rotationally symmetrical piezoelectric actuator, with low processing difficulty, easy control of processing errors, and high yield. Examples include round tube piezoelectric actuators and square tube piezoelectric actuators.

[0041] Optionally, the sheet piezoelectric actuator 200 is a single-piezoelectric actuator or a dual-piezoelectric actuator. The sheet piezoelectric actuator 200 is also a conventional actuator, with low manufacturing difficulty. This application, by combining two easily manufactured components, obtains a scanner suitable for Lissajous scanning and with guaranteed anti-coupling effect, which is less difficult to manufacture and has a higher yield rate compared to existing Lissajous scanners.

[0042] The optical fiber 300 is fixedly disposed on the upper or lower surface of the sheet-like piezoelectric actuator 200, or disposed inside the sheet-like piezoelectric actuator 200, using a cantilever support method. The cantilever support means that the portion of the front end of the optical fiber 300 extending beyond the front end of the sheet-like piezoelectric actuator 200 forms a cantilever of the optical fiber 300, and the portion of the optical fiber 300 located behind the cantilever is fixedly connected to the sheet-like piezoelectric actuator 200. In one embodiment where the optical fiber 300 is disposed inside the sheet-like piezoelectric actuator 200, the sheet-like piezoelectric actuator 200 body has a mounting hole for accommodating the optical fiber 300, and the optical fiber 300 is fixedly disposed within the mounting hole using a cantilever support method.

[0043] As an example of the cylindrical piezoelectric actuator 100:

[0044] like Figure 4 As shown, the cylindrical actuator has a cylindrical body, with the axis of the body set along the front-to-back direction.

[0045] The driving method for the cylindrical body can be either by attaching a piezoelectric sheet or by having the body itself made of piezoelectric material, with driving electrodes arranged at corresponding positions on its inner and outer surfaces. The structure of the cylindrical actuator, as well as the aforementioned arrangement of piezoelectric sheets or driving electrodes, are all conventional techniques in this field.

[0046] like Figure 5 As shown, the cylindrical actuator has a cylindrical body, which can be either a square or a rectangular cross-section. The axis of the body is set along the front-to-back direction.

[0047] The cylindrical actuator, with a similar driving method to a cylindrical body, can be driven by attaching a piezoelectric sheet, or by using a piezoelectric material as the cylindrical body itself, with driving electrodes arranged at corresponding positions on its inner and outer surfaces. The cylindrical actuator structure, as well as the aforementioned arrangement of piezoelectric sheets or driving electrodes, are all conventional techniques in this field.

[0048] It should be noted that the above embodiments are illustrative of this application and not limiting of it, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The words “comprising” or “including” do not exclude the presence of elements or steps not listed in the claims. The words “a” or “an” preceding an element do not exclude the presence of a plurality of such elements. The use of the words first, second, and third, etc., does not indicate any order and these words can be interpreted as names.

[0049] All features disclosed in this specification, except for mutually exclusive features, can be combined in any way.

[0050] 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.

[0051] This application is not limited to the specific embodiments described above. This application extends to any new features or combinations disclosed in this specification, as well as any new steps or combinations of any new methods or processes disclosed.

Claims

1. A small size Lissajous fiber scanner characterized by, It includes a base, a cylindrical piezoelectric actuator, a sheet-like piezoelectric actuator, and an optical fiber. The cylindrical piezoelectric actuator is a one-dimensional scanning piezoelectric actuator. The fixed end of the cylindrical piezoelectric actuator is fixedly connected to the base so as to be supported by the base. The cylindrical piezoelectric actuator has a first through hole that penetrates through itself along the axial direction. The base has a second through hole that connects to the first through hole. The free end of the cylindrical piezoelectric actuator vibrates along a first direction. Taking the free end of the cylindrical piezoelectric actuator as the rear end and the fixed end of the cylindrical piezoelectric actuator as the front end, and the first direction as the left-right direction,... A sheet-shaped piezoelectric actuator is disposed in the first through hole. The sheet-shaped piezoelectric actuator is disposed in a direction parallel to the horizontal plane. Its rear end is fixedly connected to the free end of the cylindrical piezoelectric actuator. The front end of the sheet-shaped piezoelectric actuator is located in the first through hole or in the second through hole. The front end of the sheet-shaped piezoelectric actuator vibrates in the vertical direction. The optical fiber is fixedly disposed at the front end of the sheet-shaped piezoelectric actuator in a cantilever support manner. The diameters of the first and second through holes are set to be no less than the swing range of the sheet-like piezoelectric actuator and the optical fiber. A cylindrical piezoelectric actuator, a sheet piezoelectric actuator, and an optical fiber constitute a scanner cantilever. The sheet piezoelectric actuator makes the natural frequency of the scanner cantilever in the horizontal direction greater than its natural frequency of the same order in the vertical direction, and makes a difference between a certain natural frequency of the scanner cantilever in the vertical direction that is closest to its natural frequency of order V in the horizontal direction and the natural frequency of order V in the horizontal direction, where V is an integer greater than or equal to 1.

2. A small size Lissajous fiber scanner as claimed in claim 1, characterized in that, The difference ensures that when the cylindrical piezoelectric actuator performs a Lissajous scan under the drive signal, the vibrations of the scanner cantilever in the horizontal and vertical directions will not couple.

3. A small size Lissajous fiber scanner as claimed in claim 1 or 2, characterized in that, The difference range is 10Hz to 12KHz.

4. A small size Lissajous fiber scanner as claimed in claim 3, characterized in that, The difference range is 1kHz to 10kHz.

5. A small-sized Lissajous fiber optic scanner as described in claim 1 or 2, characterized in that, The natural frequency of the cylindrical piezoelectric actuator in the left-right direction is the same as or similar to the natural frequency of the same order in the vertical direction.

6. A small-sized Lissajous fiber optic scanner as described in claim 1 or 2, characterized in that, The aforementioned sheet-shaped piezoelectric actuator is a single piezoelectric actuator or a dual piezoelectric actuator.

7. A small-sized Lissajous fiber optic scanner as described in claim 1 or 2, characterized in that, The optical fiber is fixedly mounted on the upper or lower surface of the sheet piezoelectric actuator or inside the sheet piezoelectric actuator in a cantilever support manner.

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