Speckle homogenization device and control method thereof

Abstract

The application provides a new speckle homogenization device and a control method thereof, and aims at solving the technical problem that the existing speckle homogenization device shares the same elastic beam in the X direction and the Y direction, which leads to a relatively complex structure of the elastic beam and a high production cost. The speckle homogenization device provided by the application is provided with a Y-axis frame and an X-axis frame, and two Y-axis elastic sheets are connected between the Y-axis frame and the X-axis frame, and two X-axis elastic sheets are connected between the X-axis frame and a bottom plate, so that the circular or elliptical motion required for speckle elimination is decomposed into separate motions in the X direction and the Y direction, and the structural requirements of the X-axis frame and the Y-axis frame are effectively simplified; the Y-axis elastic sheet and the X-axis elastic sheet adopt a sheet-shaped S-shaped structure to cooperate with the Y-axis frame and the X-axis frame, the structure of the elastic sheet is greatly simplified on the basis of ensuring the speckle homogenization performance, the size of the device is reduced, and the miniaturization of the speckle homogenization device is realized.

Description

Technical Field

[0001] This invention relates to laser projection technology, and more particularly to a speckle homogenization device and its control method. Background Technology

[0002] Laser projection technology has attracted widespread attention in the projection industry due to its advantages such as high contrast, clear imaging, vibrant colors, and high brightness. However, the strong coherence of laser light can cause speckle, which severely affects the image quality of laser projection and limits its application.

[0003] Currently, speckle homogenization devices in the industry typically homogenize speckle dynamically by rapidly changing the laser path. For example, in products like laser TVs and laser micro-projectors, this is achieved by using in-plane vibrating diffractive optical elements to rapidly change the laser path. The speckle reduction effect is closely related to the linear velocity and trajectory length of the diffractive optical element's vibration. The higher the linear velocity, the more path changes per unit time, the longer the trajectory, and the more varied the path changes, resulting in better speckle reduction. Among these, in-plane two-dimensional circular or elliptical sweeping motions formed by two-dimensional vibration coupling are preferred because they can eliminate speckle in the low-speed segment of the diffractive optical element's vibration and have a longer trajectory length relative to the diffuser.

[0004] Chinese patent CN117970659A discloses a speckle homogenizing device. It uses an elastic beam structure consisting of multiple layers of first and second straight beams connected end-to-end. The connection points between the elastic beam and the moving component, as well as the anchor points for the elastic beam, are located at the four corners of the moving component. This shortens the lever arm in the vertical direction, effectively suppressing the vertical swaying of the moving component and improving the stability of the moving component driving the diffractive optical element in in-plane two-dimensional circular or elliptical sweeping motion. However, because this speckle homogenizing device uses the same elastic beam in both the X and Y directions, the structure of the elastic beam is relatively complex, leading to higher production costs. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem that existing speckle homogenizing devices share the same elastic beam in the X and Y directions, resulting in a complex structure of the elastic beam and thus high production costs. The invention provides a new speckle homogenizing device and its control method.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] A speckle homogenizing device, characterized in that it includes a base plate, a Y-axis frame, an X-axis frame, two Y-axis springs, two X-axis springs, a diffractive optical element, a driving circuit, and N magnets, where 2≤N≤4.

[0008] The base plate, Y-axis frame, and X-axis frame are arranged horizontally from bottom to top, with gaps between each pair.

[0009] Define the length direction of the X-axis frame as the X-direction and the width direction as the Y-direction;

[0010] Both the Y-axis spring and the X-axis spring are sheet-like S-shaped structures; the two Y-axis springs are arranged opposite each other, with their upper parts vertically connected to both sides of the X-axis frame in the X direction, and their lower parts vertically connected to both sides of the Y-axis frame in the X direction; the two X-axis springs are arranged opposite each other, with their upper parts vertically connected to both sides of the X-axis frame in the Y direction, and their lower ends vertically connected to both sides of the base plate in the Y direction.

[0011] A first light-transmitting hole is provided on the Y-axis frame; a diffractive optical element is fixed on the Y-axis frame at a position directly opposite the first light-transmitting hole; a second light-transmitting hole is provided on the base plate at a position directly opposite the first light-transmitting hole, and a third light-transmitting hole is provided on the X-axis frame at a position directly opposite the first light-transmitting hole;

[0012] The driving circuit is mounted on the upper surface of the base plate and has N coils. M magnets are set on the Y-axis frame and NM magnets are set on the X-axis frame, where M=1 or 2. The N magnets correspond one-to-one with the N coils, which are used to drive the Y-axis frame and X-axis frame to resonate relative to the base plate along the Y and X directions, respectively. At the same time, the X-axis frame will drive the Y-axis frame to generate resonant motion along the X direction. The resonant motions of the Y-axis frame in the X and Y directions are superimposed, thereby driving the diffractive optical element on the Y-axis frame to perform in-plane two-dimensional circular or elliptical sweeping motion.

[0013] Furthermore, the upper part of the Y-axis spring sheet is evenly distributed with at least one first connecting through hole along the X direction, and the lower part is evenly distributed with at least one second connecting through hole along the X direction; the two side walls of the X-axis frame in the X direction are respectively provided with first connecting protrusions that are adapted to the first connecting through holes at the positions of each first connecting through hole, and the two side walls of the Y-axis frame in the X direction are respectively provided with second connecting protrusions that are adapted to the second connecting through holes at the positions of each second connecting through hole;

[0014] The upper part of the X-axis spring sheet has at least one third connecting through hole evenly distributed along the Y direction, and the lower part has two connecting holes evenly distributed along the Y direction; the two side walls of the X-axis frame in the Y direction are provided with third connecting protrusions that are adapted to the third connecting through holes at the corresponding positions of each third connecting through hole.

[0015] A slot is provided on the base plate corresponding to the position of the X-axis spring piece. On the inner side wall of the slot, a first locking protrusion is provided at the position corresponding to the outer side of the two connecting holes, and a second locking protrusion is provided on the outer side wall corresponding to the position between the two connecting holes. The vertical distance between the first locking protrusion and the second locking protrusion is adapted to the thickness of the lower part of the X-axis spring piece. The gap between the two first locking protrusions and the gaps on both sides of the second locking protrusion form three glue application positions. Adhesive is injected from the three glue application positions and overflows through the two connecting holes at the lower part of the X-axis spring piece to achieve connection.

[0016] Furthermore, when N=2, M=1; or when N=3, M=1 or 2; or when N=4, M=2.

[0017] Furthermore, N=2, M=1;

[0018] The driving circuit is configured with an L-shaped structure, with two coils respectively set on the two arms of the L-shaped structure;

[0019] The base plate is provided with an L-shaped notch adapted to the drive circuit for mounting the drive circuit.

[0020] Furthermore, a first receiving cavity is provided on the lower surface of the X-axis frame corresponding to the position of one of the coils, for placing the magnet that drives the X-axis frame;

[0021] A second receiving cavity is provided on the upper surface of the Y-axis frame corresponding to the position of another coil, for placing the magnet that drives the Y-axis frame;

[0022] The lower surface of the first receiving cavity and the bottom surface of the second receiving cavity are on the same horizontal plane so that the two magnets are located on the same horizontal plane.

[0023] Furthermore, the base plate is provided with mounting rings at its four corners for connecting with external components, which facilitates the placement of rubber gaskets inside the mounting rings for installation.

[0024] A first limiting protrusion is provided on the X-axis frame sidewall in the X direction, corresponding to the outer side of the upper outer end of the Y-axis spring piece. A second limiting protrusion is provided on the X-axis frame sidewall in the X direction, corresponding to the outer side of the lower outer end of the Y-axis spring piece. The first limiting protrusion and the second limiting protrusion are used to limit the upper and lower parts of the Y-axis spring piece, respectively, to prevent incorrect installation of the Y-axis spring piece.

[0025] A third limiting protrusion is provided on the side wall of the X-axis frame in the Y direction, corresponding to the outer side of the upper outer end of the X-axis spring, to limit the upper part of the X-axis spring and prevent incorrect installation of the X-axis spring.

[0026] In addition, the present invention also provides a control method for the above-mentioned speckle homogenization device, which is characterized by including the following steps:

[0027] Step 1: Input N driving signals into the driving circuit. The driving circuit drives N coils to work according to the N driving signals.

[0028] Step 2: N coils and corresponding magnets work together to form an electromagnetic drive, causing the magnet on the Y-axis frame to move along the Y direction and the magnet on the X-axis frame to move along the X direction.

[0029] Step 3: The Y-axis frame follows the corresponding magnet and resonates with the base plate along the Y direction. The X-axis frame follows the corresponding magnet and resonates with the base plate along the X direction. At the same time, the X-axis frame will drive the Y-axis frame to generate resonant motion along the X direction. The resonant motions of the Y-axis frame in the X and Y directions are superimposed, thereby driving the diffractive optical element on the Y-axis frame to achieve in-plane two-dimensional circular or elliptical sweeping motion.

[0030] Furthermore, in step 1, the driving signal input to the driving circuit is a driving signal based on a trapezoidal pulse width modulation waveform.

[0031] Furthermore, in step 1, the driving signal based on the trapezoidal pulse width modulation waveform is a positive and negative symmetrical waveform, and the entire cycle includes the first half of the positive waveform and the second half of the negative waveform.

[0032] The phase difference between the driving signal of the coil corresponding to the magnet on the Y-axis frame and the driving signal of the coil corresponding to the magnet on the X-axis frame is 1 / 4 cycle.

[0033] Further, in step 1, the duty cycle of the drive signal based on the trapezoidal pulse width modulation waveform increases uniformly from 0 to the maximum during the 0-1 / 8 period, remains at the maximum during the 1 / 8-3 / 8 period, decreases uniformly to 0 during the 3 / 8-4 / 8 period, increases uniformly from 0 during the 4 / 8-5 / 8 period, reaches the maximum and remains stable during the 5 / 8-7 / 8 period, and decreases uniformly from the maximum to 0 during the 3 / 8-4 / 8 period.

[0034] The advantages of this invention compared to the prior art are as follows:

[0035] 1. The speckle homogenizing device provided by this invention comprises a Y-axis frame and an X-axis frame, with two Y-axis springs connected between the Y-axis frame and the X-axis frame. Simultaneously, two X-axis springs are connected between the X-axis frame and the base plate. This decomposes the circular or elliptical motion required to eliminate speckle into separate motions along the X and Y directions. Specifically, the upper X-axis frame performs a resonant motion along the X direction, and the lower Y-axis frame performs a resonant motion along the Y direction. Simultaneously, the X-axis frame drives the Y-axis frame to produce a resonant motion along the X direction, preventing displacement of the Y-axis frame relative to the X-axis frame in the X direction. This effectively simplifies the structural requirements of the X-axis and Y-axis frames. The Y-axis and X-axis springs employ a sheet-like S-shaped structure to cooperate with the Y-axis and X-axis frames, greatly simplifying the spring structure and reducing the device size while ensuring speckle homogenizing performance, thus achieving miniaturization of the speckle homogenizing device.

[0036] 2. The speckle homogenizing device provided by the present invention has a simple overall structure, and the processing technology of the Y-axis spring, X-axis spring, Y-axis frame and X-axis frame is simple, which makes the parts cost low and reliable. At the same time, the overall assembly process of the speckle homogenizing device of the present invention is also relatively simple and convenient, effectively reducing the assembly and production cost. The simplification of both parts and assembly achieves the effect of significantly reducing the overall product cost.

[0037] 3. The speckle homogenization device provided by the present invention makes the connection between the Y-axis spring and the X-axis frame and the Y-axis frame, and the connection between the X-axis spring and the X-axis frame and the base plate more flexible and reliable. At the same time, the base plate has a groove forming a dispensing position. The adhesive injected into the three dispensing positions can overflow through the two connecting holes at the bottom of the X-axis spring and connect the three dispensing positions, thereby fixing the X-axis spring firmly.

[0038] 4. The speckle homogenizing device provided by the present invention has the bottom surfaces of the first receiving cavity and the second receiving cavity on the same horizontal plane, which can effectively compress the volume of the entire device.

[0039] 5. The control method of the speckle homogenization device provided by the present invention is simple and convenient, with high control precision, and can accurately drive the diffraction optical elements on the Y-axis frame to achieve in-plane two-dimensional circular or elliptical sweeping motion.

[0040] 6. The control method of the speckle homogenization device provided by the present invention adopts a driving signal based on trapezoidal pulse width modulation waveform, which can avoid high-frequency noise caused by square wave driving and has a greater driving force than sine wave driving. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of an embodiment of the speckle homogenization device of the present invention;

[0042] Figure 2 for Figure 1Exploded view;

[0043] Figure 3 This is a schematic diagram of the movement direction of the free end of the X-axis spring in an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of the motion of the Y-axis frame and the X-axis frame in an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of the structure in this invention, in which two magnets are set on the X-axis frame and the third magnet is set on the Y-axis frame.

[0046] Figure 6 This is a schematic diagram of the structure of the present invention, in which one magnet is set on the X-axis frame and the other two magnets are set on the Y-axis frame;

[0047] Figure 7 This is a schematic diagram of the structure in this invention, in which two magnets are set on the X-axis frame and the other two magnets are set on the Y-axis frame.

[0048] Figure 8 This is a waveform diagram of the driving signal based on the trapezoidal pulse width modulation waveform in step 1 of an embodiment of the control method of a speckle homogenizing device of the present invention.

[0049] The attached figures are labeled as follows:

[0050] 1-Base plate, 11-Second light-transmitting hole, 12-Slot, 121-First locking protrusion, 122-Second locking protrusion, 13-Mounting ring; 2-Y-axis frame, 21-First light-transmitting hole, 22-Second connecting protrusion, 23-Second limiting protrusion; 3-X-axis frame, 31-Third light-transmitting hole, 32-First connecting protrusion, 33-Third connecting protrusion, 34-First limiting protrusion, 35-Third limiting protrusion; 4-Y-axis spring; 5-X-axis spring; 6-Diffractive optical element; 7-Drive circuit; 8-Magnet. Detailed Implementation

[0051] To make the advantages and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] like Figure 1 , Figure 2 As shown, a speckle homogenizing device includes a base plate 1, a Y-axis frame 2, an X-axis frame 3, two Y-axis springs 4, two X-axis springs 5, a diffractive optical element 6, a driving circuit 7, and two magnets 8. The base plate 1, Y-axis frame 2, and X-axis frame 3 are arranged horizontally from bottom to top, with gaps between each pair. The length direction of the X-axis frame 3 is defined as the X-direction, and the width direction as the Y-direction.

[0053] The Y-axis spring 4 has a sheet-like S-shaped structure. Two Y-axis springs 4 are arranged opposite each other, with their upper ends vertically connected to both sides of the X-axis frame 3 in the X direction, and their lower ends vertically connected to both sides of the Y-axis frame 2 in the X direction. Specifically, the upper part of the Y-axis spring 4 has three first connecting through holes evenly distributed along the X direction, and the lower part has two second connecting through holes evenly distributed along the X direction. On the two side walls of the X-axis frame 3 in the X direction, corresponding to the positions of the first connecting through holes, there are first connecting protrusions 32 that fit into the first connecting through holes. On the two side walls of the Y-axis frame 2 in the X direction, corresponding to the positions of the second connecting through holes, there are second connecting protrusions 22 that fit into the second connecting through holes. The upper part of the Y-axis spring 4 serves as a free end, with its three first connecting through holes corresponding to and engaging with the three first connecting protrusions 32 on the X-axis frame 3. The lower part serves as a fixed end, with its two second connecting through holes corresponding to and engaging with the two second connecting protrusions 22 on the Y-axis frame 2, thereby establishing a motion correlation between the X-axis frame 3 and the Y-axis frame 2.

[0054] The X-axis spring 5 is also a sheet-like S-shaped structure. Two X-axis springs 5 ​​are arranged opposite each other, with their upper parts vertically connected to both sides of the X-axis frame 3 in the Y direction, and their lower parts vertically connected to both sides of the base plate 1 in the Y direction. Specifically, the upper part of the X-axis spring 5 has two third connecting through holes evenly distributed along the Y direction, and the side walls of the X-axis frame 3 in the Y direction are respectively provided with third connecting protrusions 33 that are adapted to the third connecting through holes at the corresponding positions of the third connecting through holes. The lower part of the X-axis spring sheet 5 has two connecting holes evenly distributed along the Y direction. A slot 12 is provided on the base plate 1 corresponding to the position of the X-axis spring sheet 5. On the inner side wall of the slot 12, a first locking protrusion 121 is provided at the position corresponding to the outer side of the two connecting holes. On the outer side wall of the slot 12, a second locking protrusion 122 is provided at the position corresponding to the position between the two connecting holes. The vertical distance between the first locking protrusion 121 and the second locking protrusion 122 is adapted to the thickness of the lower part of the X-axis spring sheet 5, and is used to accommodate and lock the lower part of the X-axis spring sheet 5. The gap between the two first locking protrusions 121 and the gaps on both sides of the second locking protrusion 122 form three glue application positions. Adhesive is injected from the three glue application positions and overflows through the two connecting holes at the lower part of the X-axis spring sheet 5 to achieve the connection of the three glue application positions, thereby fixing the X-axis spring sheet firmly. The upper part of the X-axis spring piece 5 serves as a free end, with its two third connecting through holes corresponding to and engaging with the two third connecting protrusions 33 on the X-axis frame 3. The lower part serves as a fixed end, engaging with the two first locking protrusions 121 and the second locking protrusion 122 to secure it, thereby establishing a motion association between the X-axis frame 3 and the base plate 1. In other embodiments of the present invention, a protrusion may be provided on the side of the base plate 1 to replace the slot 12, thereby achieving a fixed engagement with the two connecting holes of the X-axis spring piece 5. No specific limitation is made here.

[0055] In other embodiments of the present invention, the connection between the Y-axis spring 4 and the X-axis frame 3 and the Y-axis frame 2, and the connection between the X-axis spring 5 and the X-axis frame 3 and the base plate 1 can also be achieved by other connection methods, and no specific restrictions are imposed here.

[0056] When the fixed end (lower part) of the Y-axis spring 4 or X-axis spring 5 is fixed, the stiffness in the plane perpendicular to the Y-axis spring 4 or X-axis spring 5 is much smaller than the stiffness in any other direction. Therefore, when the free end (upper part) of the Y-axis spring 4 or X-axis spring 5 is driven to move in the direction perpendicular to the plane of the Y-axis spring 4 or X-axis spring 5, the free end of the Y-axis spring 4 or X-axis spring 5 can only move in the direction perpendicular to the plane of the Y-axis spring 4 or X-axis spring 5. Figure 3 The figure shows a schematic diagram of the movement direction of the free end of the X-axis spring piece 5.

[0057] In addition, a first limiting protrusion 34 is provided on the X-direction sidewall of the X-axis frame 3 at the position corresponding to the outer outer end of the upper part of the Y-axis spring 4, and a second limiting protrusion 23 is provided on the X-direction sidewall of the Y-axis frame 2 at the position corresponding to the outer outer end of the lower part of the Y-axis spring 4. The first limiting protrusion 34 and the second limiting protrusion 23 are used to limit the upper and lower parts of the Y-axis spring 4, respectively, to prevent incorrect installation of the Y-axis spring 4. A third limiting protrusion 35 is provided on the Y-direction sidewall of the X-axis frame 3 at the position corresponding to the outer outer end of the upper part of the X-axis spring 5, to limit the upper part of the X-axis spring 5, to prevent incorrect installation of the X-axis spring 5. In this embodiment, mounting rings 13 for connecting with external components are provided at the four corners of the base plate 1. The mounting rings 13 can be open or closed. In other embodiments of the present invention, the number and position of the mounting rings 13 are not specifically limited, and they can be set at any reasonable position on the base plate 1 that does not obstruct light transmission.

[0058] A first light-transmitting hole 21 is provided on the Y-axis frame 2, and a diffractive optical element 6 is fixed on the Y-axis frame 2 at a position directly opposite to the first light-transmitting hole 21; a second light-transmitting hole 11 is provided on the base plate 1 at a position directly opposite to the first light-transmitting hole 21, and a third light-transmitting hole 31 is provided on the X-axis frame 3 at a position directly opposite to the first light-transmitting hole 21, for the purpose of realizing light transmission.

[0059] In this embodiment, there are two magnets 8, and the driving circuit 7 is configured with an L-shaped structure, with two coils on each arm of the L-shaped structure. The base plate 1 has an L-shaped notch adapted to the driving circuit 7, allowing the driving circuit 7 to be mounted on the L-shaped notch on the upper surface of the base plate 1, further reducing the volume of the speckle homogenizing device. A first receiving cavity is provided on the lower surface of the X-axis frame 3 corresponding to the position of one of the coils, for placing the magnet 8 driving the X-axis frame 3; a second receiving cavity is provided on the upper surface of the Y-axis frame 2 corresponding to the position of the other coil, for placing the magnet 8 driving the Y-axis frame 2. The two coils and their corresponding magnets 8 form an electromagnetic drive, as shown below. Figure 4 As shown, one magnet 8 drives the X-axis frame 3 to resonate relative to the base plate 1 along the X direction, and another magnet 8 drives the Y-axis frame 2 to resonate relative to the base plate 1 along the Y direction. Simultaneously, the movement of the X-axis frame 3 causes the Y-axis frame 2 to resonate along the X direction, resulting in the superposition of the X and Y-direction resonant movements of the Y-axis frame 2. This, in turn, drives the diffraction optical element 6 mounted on the Y-axis frame 2 to perform in-plane two-dimensional circular or elliptical sweeping motion. In other embodiments of the invention, the number of magnets 8 can also be set to three or four. Correspondingly, the shape of the driving circuit 7 can also be adjusted to a C-shaped structure or a square structure, etc., without limitation. Figure 5 , Figure 6 The diagram shown is a schematic of the speckle homogenization device when the number of magnets 8 is 3. Figure 5 This is a schematic diagram showing a structure with two magnets 8 mounted on the X-axis frame 3 and a third magnet 8 mounted on the Y-axis frame 2. Figure 6 A schematic diagram showing a structure in which one magnet 8 is set on the X-axis frame 3 and the other two magnets 8 are set on the Y-axis frame 2. Figure 7 This is a schematic diagram of the speckle homogenization device when the number of magnets 8 is 4, where two magnets 8 are set on the X-axis frame 3 and the other two magnets 8 are set on the Y-axis frame 2.

[0060] Preferably, the lower surface of the first receiving cavity and the bottom surface of the second receiving cavity are on the same horizontal plane to ensure that the two magnets 8 are installed on the same horizontal plane, thereby effectively compressing the volume of the entire device. Accordingly, when the number of magnets 8 is three or four, it is preferable to ensure that multiple magnets 8 are installed on the same horizontal plane.

[0061] The control method for the above-mentioned speckle homogenization device specifically includes the following steps:

[0062] Step 1: Input two drive signals based on trapezoidal pulse width modulation waveforms into the drive circuit 7. The drive circuit 7 drives the two coils to work according to the two drive signals. The drive signals based on trapezoidal pulse width modulation waveforms can avoid the high-frequency noise caused by square wave drive and have a greater driving force than sine wave drive.

[0063] In this embodiment, the drive signal input to the drive circuit 7, based on trapezoidal pulse width modulation (TPMS), is a symmetrical positive and negative waveform. The entire cycle includes the first half of the positive waveform and the latter half of the negative waveform. The waveform diagram of the drive signal based on trapezoidal pulse width modulation is shown below. Figure 8 As shown, the 0-1 / 8 period of the entire cycle is the duty cycle rising period, where the duty cycle rises uniformly from 0 to its maximum; the 1 / 8-3 / 8 period is the duty cycle plateau period, where the duty cycle is at its maximum and remains constant; the 3 / 8-4 / 8 period is the duty cycle falling period, where the duty cycle falls uniformly from its maximum to 0. The latter half of the cycle shows the same changes as the first half, but the current is negative; the phase difference between the drive signals of the two coils is 1 / 4 period; the entire cycle T contains N small-cycle waveforms, and the frequency of the small cycles is... To reduce audible noise in the entire system, the frequency F of the small period needs to be at least greater than the maximum frequency audible to the human ear, i.e., F > 20 kHz. In other embodiments of the invention, the phase difference between the driving signal of the coil corresponding to the magnet 8 on the Y-axis frame 2 and the driving signal of the coil corresponding to the magnet 8 on the X-axis frame 3 is 1 / 4 period.

[0064] Step 2: The two coils cooperate with the corresponding magnets 8 to form an electromagnetic drive, causing the magnet 8 located on the Y-axis frame 2 to produce a displacement along the Y direction, and the magnet 8 located on the X-axis frame 3 to produce a displacement along the X direction.

[0065] Step 3: Due to the constraints of the Y-axis spring 4 and the X-axis spring 5, the Y-axis frame 2 moves in a resonant motion along the Y direction following the displacement of the corresponding magnet 8, and the X-axis frame 3 moves in a resonant motion along the X direction following the displacement of the corresponding magnet 8. At the same time, the movement of the X-axis frame 3 will drive the Y-axis frame 2 to generate a resonant motion along the X direction, so that the resonant motions of the Y-axis frame 2 in the X and Y directions are superimposed, thereby driving the diffractive optical element 6 installed on the Y-axis frame 2 to achieve in-plane two-dimensional circular or elliptical sweeping motion.

[0066] The above description is only used to illustrate the technical solutions of the present invention, and is not intended to limit them. For those skilled in the art, modifications can be made to the specific technical solutions described in the above embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions protected by the present invention.

Claims

1. A speckle homogenizing device, characterized in that: It includes a base plate (1), a Y-axis frame (2), an X-axis frame (3), two Y-axis springs (4), two X-axis springs (5), a diffractive optical element (6), a driving circuit (7), and N magnets (8), where 2≤N≤4; The base plate (1), the Y-axis frame (2) and the X-axis frame (3) are arranged horizontally from bottom to top, with gaps between each pair; Define the length direction of the X-axis frame (3) as the X direction and the width direction as the Y direction; The Y-axis spring (4) and X-axis spring (5) are both sheet-like S-shaped structures; the two Y-axis springs (4) are arranged opposite to each other, with their upper parts vertically connected to both sides of the X-axis frame (3) in the X direction, and their lower parts vertically connected to both sides of the Y-axis frame (2) in the X direction; the two X-axis springs (5) are arranged opposite to each other, with their upper parts vertically connected to both sides of the X-axis frame (3) in the Y direction, and their lower ends vertically connected to both sides of the base plate (1) in the Y direction. The Y-axis frame (2) has a first light-transmitting hole (21); the diffractive optical element (6) is fixed on the Y-axis frame (2) at a position directly opposite to the first light-transmitting hole (21); the base plate (1) has a second light-transmitting hole (11) at a position directly opposite to the first light-transmitting hole (21); and the X-axis frame (3) has a third light-transmitting hole (31) at a position directly opposite to the first light-transmitting hole (21). The driving circuit (7) is installed on the upper surface of the base plate (1), on which N coils are provided; M magnets (8) are set on the Y-axis frame (2), and NM magnets (8) are set on the X-axis frame (3), where M=1 or 2; the N magnets (8) correspond one-to-one with the N coils, and are used to drive the Y-axis frame (2) and the X-axis frame (3) to resonate relative to the base plate (1) along the Y and X directions, respectively. At the same time, the X-axis frame (3) will drive the Y-axis frame (2) to generate resonant motion along the X direction, so that the resonant motion of the Y-axis frame (2) in the X and Y directions is superimposed, thereby driving the diffractive optical element (6) on the Y-axis frame (2) to perform in-plane two-dimensional circular or elliptical sweeping motion.

2. The speckle homogenizing device according to claim 1, characterized in that: The upper part of the Y-axis spring (4) is evenly distributed with at least one first connecting through hole along the X direction, and the lower part is evenly distributed with at least one second connecting through hole along the X direction; the two side walls of the X-axis frame (3) in the X direction are respectively provided with a first connecting protrusion (32) that matches the first connecting through hole at the position of each first connecting through hole, and the two side walls of the Y-axis frame (2) in the X direction are respectively provided with a second connecting protrusion (22) that matches the second connecting through hole at the position of each second connecting through hole. The upper part of the X-axis spring (5) is evenly distributed with at least one third connecting through hole along the Y direction, and the lower part is evenly distributed with two connecting holes along the Y direction; the two side walls of the X-axis frame (3) in the Y direction are provided with third connecting protrusions (33) that are adapted to the third connecting through holes at the corresponding positions of each third connecting through hole. The base plate (1) is provided with a slot (12) at the position corresponding to the X-axis spring sheet (5). On the inner side wall of the slot (12), a first locking protrusion (121) is provided at the position corresponding to the outer side of the two connecting holes. On the outer side wall of the slot (12), a second locking protrusion (122) is provided at the position corresponding to the position between the two connecting holes. The vertical distance between the first locking protrusion (121) and the second locking protrusion (122) is adapted to the thickness of the lower part of the X-axis spring sheet (5). The gap between the two first locking protrusions (121) and the gaps on both sides of the second locking protrusion (122) form three glue application positions. The adhesive is injected from the three glue application positions and overflows through the two connecting holes at the lower part of the X-axis spring sheet (5) to achieve communication.

3. The speckle homogenizing device according to claim 2, characterized in that: N=2, M=1; Alternatively, N=3, M=1 or 2; Alternatively, N=4, M=2.

4. The speckle homogenizing device according to claim 3, characterized in that: N=2, M=1; The driving circuit (7) is configured as an L-shaped structure, with two coils respectively set on the two arms of the L-shaped structure; The base plate (1) is provided with an L-shaped notch adapted to the drive circuit (7) for mounting the drive circuit (7).

5. The speckle homogenizing device according to claim 4, characterized in that: The lower surface of the X-axis frame (3) is provided with a first receiving cavity corresponding to the position of one of the coils, for placing the magnet (8) that drives the X-axis frame (3). The upper surface of the Y-axis frame (2) is provided with a second receiving cavity corresponding to the position of another coil, which is used to place the magnet (8) that drives the Y-axis frame (2). The lower surface of the first receiving cavity and the bottom surface of the second receiving cavity are on the same horizontal plane.

6. The speckle homogenizing device according to claim 5, characterized in that: The base plate (1) is provided with mounting rings (13) at its four corners for connecting with external components; the X-axis frame (3) has a first limiting protrusion (34) on its X-direction sidewall corresponding to the outer side of the upper end of the Y-axis spring (4); the Y-axis frame (2) has a second limiting protrusion (23) on its X-direction sidewall corresponding to the outer side of the lower end of the Y-axis spring (4); the first limiting protrusion (34) and the second limiting protrusion (23) are used to limit the upper and lower parts of the Y-axis spring (4) respectively; A third limiting protrusion (35) is provided on the Y-direction side wall of the X-axis frame (3) at the position corresponding to the outer side of the upper outer end of the X-axis spring (5), which is used to limit the upper part of the X-axis spring (5).

7. A control method for the speckle homogenizing device according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Input N driving signals into the driving circuit (7), and the driving circuit (7) drives N coils to work according to the N driving signals; Step 2: N coils and corresponding magnets (8) work together to form an electromagnetic drive, causing the magnet (8) on the Y-axis frame (2) to move along the Y direction and the magnet (8) on the X-axis frame (3) to move along the X direction. Step 3: The Y-axis frame (2) follows the corresponding magnet (8) and moves resonantly along the Y direction relative to the base plate (1). The X-axis frame (3) follows the corresponding magnet (8) and moves resonantly along the X direction relative to the base plate (1). At the same time, the X-axis frame (3) will drive the Y-axis frame (2) to generate resonant motion along the X direction, so that the resonant motion of the Y-axis frame (2) in the X and Y directions is superimposed, thereby driving the diffractive optical element (6) on the Y-axis frame (2) to realize in-plane two-dimensional circular or elliptical sweeping motion.

8. The control method of the speckle homogenization device according to claim 7, characterized in that: In step 1, the driving signal input to the driving circuit (7) is a driving signal based on the trapezoidal pulse width modulation waveform.

9. The control method of the speckle homogenization device according to claim 8, characterized in that: In step 1, the driving signal based on the trapezoidal pulse width modulation waveform is a positive and negative symmetrical waveform, and the entire cycle includes the first half of the positive waveform and the second half of the negative waveform. The phase difference between the driving signal of the coil corresponding to the magnet (8) on the Y-axis frame (2) and the driving signal of the coil corresponding to the magnet (8) on the X-axis frame (3) is 1 / 4 cycle.

10. The control method of the speckle homogenization device according to claim 9, characterized in that: In step 1, the duty cycle of the drive signal based on the trapezoidal pulse width modulation waveform increases uniformly from 0 to the maximum during the 0-1 / 8 period, remains at the maximum during the 1 / 8-3 / 8 period, decreases uniformly to 0 during the 3 / 8-4 / 8 period, increases uniformly from 0 during the 4 / 8-5 / 8 period, reaches the maximum and remains stable during the 5 / 8-7 / 8 period, and decreases uniformly from the maximum to 0 during the 3 / 8-4 / 8 period.

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