Laser speckle suppression device and laser projection apparatus

Abstract

The present application relates to a laser speckle suppression device and a laser projection apparatus. The laser speckle suppression device comprises: a base plate, which has a first surface and a second surface arranged opposite each other, and comprises a through hole passing through the first surface and the second surface; a first optical element, which is arranged at the through hole, and is configured to transmit a laser beam so as to perform first suppression on speckles of the laser beam; an elastic member, which has one end connected to the first optical element and the other end connected to the base plate; a vibration source, which is connected to the base plate, and drives the first optical element by means of the elastic member to vibrate in the through hole, wherein the first optical element and the elastic member form a spring oscillator, and the vibration frequency of the vibration source is close to or equal to the natural frequency of the spring oscillator, such that the vibration source resonates with the spring oscillator; and a second optical element, which is located on a light path of the laser beam and is configured to perform second suppression on the speckles of the laser beam. The laser speckle suppression device in the present application has low power consumption, a simple structure, a small volume and a low manufacturing cost.

Description

Laser speckle suppression device and laser projection equipment

[0001] Citation of relevant applications

[0002] This disclosure claims the full benefits of the invention patent application No. 202410494547.5, entitled "Laser Speckle Suppression Device and Laser Projection Equipment," filed with the State Intellectual Property Office of the People's Republic of China on April 23, 2024, and the invention patent application No. 202410496687.6, also entitled "Laser Speckle Suppression Device and Laser Projection Equipment," filed with the State Intellectual Property Office of the People's Republic of China on April 23, 2024, the entire contents of which are incorporated herein by reference.

[0003] field

[0004] This application relates to the field of projection display technology, and in particular to a laser speckle suppression device and a laser projection device.

[0005] background

[0006] As a new generation of projection light source, laser has the characteristics of high brightness, good monochromaticity and small emission angle. However, due to the high coherence of laser, projection products using laser are usually accompanied by speckle phenomenon, which affects the consumer experience.

[0007] Various measures have been taken in related technologies to improve the speckle problem of lasers, such as setting dynamic or static diffusion components in the illumination optical path, or using a combination of dynamic and static components to eliminate speckle. However, the speckle elimination effect of this method in laser display still cannot meet the display requirements, and the structure is complex and the cost is high.

[0008] Overview

[0009] The purpose of this application is to provide a laser speckle suppression device and a laser projection device, which utilizes the principle of resonance so that the vibration source only needs a small amount of vibration energy to make the diffuser generate a large amount of vibration. It has low power consumption, simple structure, small size and low manufacturing cost.

[0010] In a first aspect, an embodiment of the present application provides a laser speckle suppression device, including: a substrate having a first surface and a second surface disposed opposite to each other, the substrate including a through hole penetrating the first surface and the second surface; a first optical element disposed at the through hole, the first optical element being configured to transmit a laser beam to perform a first suppression on the speckle of the laser beam; an elastic member, one end of which is connected to the first optical element and the other end of which is connected to the substrate; a vibration source connected to the substrate, the vibration source driving the first optical element to vibrate in the through hole through the elastic member, wherein the first optical element and the elastic member form a spring oscillator, and the vibration frequency of the vibration source is close to or the same as the natural frequency of the spring oscillator to resonate with the spring oscillator; and a second optical element located in the optical path of the laser beam for performing a second suppression on the speckle of the laser beam.

[0011] In a possible implementation, the elastic member includes N to N coils of springs disposed coplanarly, and adjacent coils of springs are connected by connecting portions, where N≥2.

[0012] In a possible implementation, two connecting portions symmetrically distributed along a first direction are provided between the i-th coil of spring and the (i + 1)-th coil of spring, and two connecting portions symmetrically distributed along a second direction are provided between the (i + 1)-th coil of spring and the (i + 2)-th coil of spring, the first direction and the second direction being perpendicular to each other, where 1≤i<N and i is an odd number.

[0013] In a possible implementation, the number of elastic members is at least two, and the at least two elastic members are spaced apart along a direction perpendicular to the diffusion surface of the first optical element.

[0014] In a possible implementation, a support member is provided between two connecting portions corresponding to two adjacent elastic members.

[0015] In a possible implementation, both the first optical element and the second optical element are diffusion sheets. After the laser beam passes through the first optical element, a first suppression is performed on the speckle of the laser beam, and the laser beam exiting from the first optical element passes through the second optical element and then exits, suppressing the speckle of the laser beam again.

[0016] In a second aspect, an embodiment of the present application provides a laser speckle suppression device, including:

[0017] a substrate having a through hole;

[0018] a first optical element disposed at the through hole;

[0019] an elastic member, one end of which is connected to the first optical element and the other end of which is connected to the substrate;

[0020] A vibration source, connected to the substrate, the vibration source drives the first optical element to vibrate in the through hole through the elastic member. Among them, the first optical element and the elastic member form a spring oscillator, and the vibration frequency of the vibration source is close to or the same as the natural frequency of the spring oscillator to generate resonance with the spring oscillator.

[0021] In a possible implementation, the elastic member includes N coils of springs arranged coplanarly, and adjacent coils of springs are connected by connecting parts, where N≥2.

[0022] In a possible implementation, two connecting parts symmetrically distributed along the first direction are provided between the i-th coil of the spring and the (i + 1)-th coil of the spring, and two connecting parts symmetrically distributed along the second direction are provided between the (i + 1)-th coil of the spring and the (i + 2)-th coil of the spring. The first direction and the second direction are perpendicular to each other, where 1≤i<N and i is an odd number.

[0023] In a possible implementation, the number of the elastic members is at least two, and at least two elastic members are arranged at intervals along a direction perpendicular to the diffusion surface of the first optical element.

[0024] In a possible implementation, a support member is provided between two connecting parts corresponding to two adjacent elastic members.

[0025] In a possible implementation, it further includes a second optical element. The first optical element is used to transmit a laser beam to perform a first suppression on the speckle of the laser beam. The second optical element is located in the optical path of the laser beam and is used to perform a second suppression on the speckle of the laser beam.

[0026] In a possible implementation, both the first optical element and the second optical element are diffuser sheets. After the laser beam passes through the first optical element, the speckle of the laser beam is first suppressed. The laser beam emitted from the first optical element passes through the second optical element and then exits, suppressing the speckle of the laser beam again.

[0027] In a possible implementation, the first optical element is a diffuser sheet, and the second optical element is a mirror. After the laser beam passes through the first optical element, the speckle of the laser beam is first suppressed. The laser beam emitted from the first optical element is reflected when it reaches the second optical element, and the reflected laser beam passes through the first optical element again and then exits, suppressing the speckle of the laser beam again.

[0028] In a third aspect, an embodiment of the present application provides a laser speckle suppression device, including:

[0029] A first optical element, which is a first optical element for transmitting a laser beam;

[0030] An elastic member is provided on the outer peripheral side of the first optical element, and the first optical element and the elastic member form a spring oscillator. The elastic member includes a moving part, an elastic part, and a fixed part arranged in sequence from the inside to the outside. The moving part is connected to the first optical element, one end of the elastic part is connected to the moving part, and the other end of the elastic part is connected to the fixed part; and

[0031] A vibration source is connected to the fixed part. The vibration source resonates with the spring oscillator in a preset mode, driving the first optical element to vibrate in a preset direction to suppress the speckle of the laser beam.

[0032] In a possible implementation, the elastic part is a planar spiral spring, a helical spring or a flexible ring-shaped structural member.

[0033] In a possible implementation, the elastic part includes N coils of springs arranged coplanarly, and N≥2;

[0034] The elastic member further includes a connecting part. Adjacent coils of springs are connected by the connecting part. The innermost coil of spring is connected to the moving part by the connecting part, and the outermost coil of spring is connected to the fixed part by the connecting part.

[0035] In a possible implementation, two connecting parts symmetrically distributed along a first direction are provided between the i-th coil of spring and the (i + 1)-th coil of spring, and two connecting parts symmetrically distributed along a second direction are provided between the (i + 1)-th coil of spring and the (i + 2)-th coil of spring. The first direction and the second direction are perpendicular to each other, where 1≤i<N and i is an odd number.

[0036] In a possible implementation, the gap d between adjacent coils of springs satisfies the following condition: 0.5mm < d < 2mm.

[0037] In a possible implementation, the vibration source is arranged on the plane where the fixed part is located, and the vibration source is a linear vibration motor or a rotary motor.

[0038] In a possible implementation, the number of the elastic members is at least two, and at least two elastic members are arranged at intervals along a direction perpendicular to the first optical element.

[0039] In a possible implementation, a support component is provided between the elastic parts of two adjacent elastic members.

[0040] In one possible implementation, the distance between two adjacent elastic elements is 0.5 mm to 1 mm.

[0041] Fourthly, embodiments of this application provide a laser projection device, including: a laser source for emitting a laser beam; and a laser speckle suppression device as described above, disposed in the optical path of the laser beam.

[0042] The laser speckle suppression device and laser projection equipment provided in this application embodiment have a first optical element and an elastic element forming a spring oscillator. The vibration frequency of the vibration source is close to or the same as the natural frequency of the spring oscillator to resonate with it. Utilizing the resonance principle, the vibration source only requires a small amount of vibration energy to drive the first optical element to generate a large vibration through the elastic element. This results in low power consumption, a simple structure, small size, and low manufacturing cost. When applied to laser projection equipment, this laser speckle suppression device can effectively improve the speckle problem of the laser beam and enhance the display effect of the laser projection equipment.

[0043] Brief description of the attached figures

[0044] To more clearly illustrate the technical solutions in the embodiments of this application 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, in the drawings, the same parts use the same reference numerals, and the drawings are not drawn to scale.

[0045] Figure 1 shows a simplified structural schematic diagram of a laser speckle suppression device provided in an embodiment of this application;

[0046] Figure 2 shows a three-dimensional structural schematic diagram of the laser speckle suppression device shown in Figure 1;

[0047] Figure 3 shows an exploded structural diagram of the laser speckle suppression device shown in Figure 2;

[0048] Figure 4 shows a schematic diagram of the front structure of the laser speckle suppression device shown in Figure 2;

[0049] Figure 5 shows a schematic diagram of the back structure of the laser speckle suppression device shown in Figure 2;

[0050] Figure 6 shows a schematic diagram of the elastic element in the laser speckle suppression device shown in Figure 2;

[0051] Figure 7 shows a simplified structural schematic diagram of a laser speckle suppression device provided in another embodiment of this application;

[0052] Figure 8 shows a simplified structural schematic diagram of a laser speckle suppression device provided in another embodiment of this application.

[0053] Figure 9 shows a three-dimensional structural schematic diagram of a laser speckle suppression device provided in an embodiment of this application;

[0054] Figure 10 shows a schematic diagram of the vibration modes of the laser speckle suppression device shown in Figure 8 along the horizontal direction of the horizontal plane;

[0055] Figure 11 shows a schematic diagram of the vibration modes of the laser speckle suppression device shown in Figure 8 along the vertical direction of the horizontal plane.

[0056] Figure 12 shows a schematic diagram of the scenario where the spring of the elastic element of the laser speckle suppression device shown in Figure 8 undergoes collision interference during vibration;

[0057] Figure 13 shows a schematic diagram of the structure of the elastic member with the connecting part shown in Figure 12;

[0058] Figure 14 shows a schematic diagram of the structure of an elastic element of the laser speckle suppression device shown in Figure 8;

[0059] Figure 15 shows a schematic diagram of another elastic element of the laser speckle suppression device shown in Figure 8;

[0060] Figure 16 shows a three-dimensional structural schematic diagram of a laser speckle suppression device provided in another embodiment of this application;

[0061] Figure 17 shows a schematic diagram of the scenario in Figure 16 where the springs of two adjacent elastic elements collide and interfere during vibration;

[0062] Figure 18 shows an exploded structural diagram of the support assembly between two adjacent elastic members in Figure 17.

[0063] Explanation of reference numerals in the attached drawings: 1. First optical element; 10. Substrate; 101. First surface; 102. Second surface; 103. Through hole; 104. First groove; 105. Second groove; H. Positioning hole; 11. Elastic element; 111. Spring; 112. Connecting part; 113. Moving part; 114. Fixing part; 110. Elastic part; 12. Vibration source; 13. Circuit board; 14. Compression spring; 15. Fastener; 2. Second optical element; 3. Support assembly; 31. First support member; 32. Second support member; 4. Diffuser.

[0064] Detailed Explanation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0066] Laser beams are characterized by high brightness, good monochromaticity, and a small emission angle, while also exhibiting high coherence. This high coherence can cause speckle effects in laser projection displays. The speckle effect refers to the phenomenon where, when a coherent light source illuminates an optically rough surface such as a wall, paper, or frosted glass (where the average undulation is orders of magnitude greater than the laser wavelength), the scattered light interferes in space due to a constant phase difference, identical light wave frequency, and consistent vibration direction. Some interference is constructive, while other interference is destructive, resulting in a random spatial intensity distribution and a granular structure. The end result is the appearance of alternating bright and dark spots on the screen, i.e., speckle. These unfocused spots appear flickering to the human eye, causing discomfort during prolonged viewing and severely impacting the quality of the projected image, thus reducing the user's viewing experience.

[0067] Various measures have been taken in related technologies to improve the speckle problem of lasers. For example, dynamic or static diffusion components are set in the illumination optical path. Dynamic diffusion components include rotating and electromagnetically driven types. The rotating motor in the speckle elimination structure is large, which leads to an increase in the overall optical path volume. The electromagnetically driven type requires a combination of electromagnetic and spring systems to achieve horizontal vibration, as well as a support structure. This makes the overall structure more complex and has more components, resulting in higher costs for both methods.

[0068] Therefore, this application provides a laser speckle suppression device that suppresses the speckle of the laser beam by combining dynamic and static optical elements, effectively improving the speckle reduction effect of the laser beam, and has low power consumption, simple structure, small size, and low manufacturing cost.

[0069] As shown in Figures 1 to 5, the laser speckle suppression device provided in this application includes: a substrate 10, a first optical element 1, an elastic element 11, a vibration source 12, and a second optical element 2.

[0070] The substrate 10 has a first surface 101 and a second surface 102 disposed opposite to each other, and the substrate 10 includes a through hole 103 penetrating the first surface 101 and the second surface 102. The substrate 10 can be a metal plate, such as an aluminum plate, and is used to provide the structural strength and stiffness required for vibration of the first optical element 1, the elastic element 11, the vibration source 12 and the second optical element 2.

[0071] The first optical element 1 is disposed at the through hole 103. The first optical element 1 is used to transmit the laser beam to suppress the speckle of the laser beam for the first time. One end of the elastic member 11 is connected to the first optical element 1, and the other end is connected to the substrate 10.

[0072] The vibration source 12 is connected to the substrate 10. The vibration source 12 drives the first optical element 1 to vibrate within the through-hole 103 via the elastic element 11. The first optical element 1 and the elastic element 11 form a spring oscillator. The vibration frequency of the vibration source 12 is close to or the same as the natural frequency of the spring oscillator to resonate with it. The vibration source 12 can be a linear vibration motor or a rotary motor, or other forms of vibration devices, such as, but not limited to, a rotating fan, a fluorescent wheel, and / or a color filter wheel. The vibration source 12 is disposed on the plane of the substrate 10, allowing vibration energy to be directly transmitted to the spring oscillator via the shortest path, reducing energy loss. In this text, "close to" means that the vibration frequency of the vibration source 12 differs from the natural frequency of the elastic element 11 in a preset mode by no more than ±10%.

[0073] The second optical element 2 is located in the optical path of the laser beam and is used to suppress the speckle of the laser beam a second time. Thus, after the laser beam passes through the first optical element 1 and the second optical element 2, the speckle of the laser beam is suppressed twice.

[0074] As an optional implementation, both the first optical element 1 and the second optical element 2 are diffusers. After the laser beam passes through the first optical element 1, the speckle of the laser beam is suppressed for the first time. After the laser beam emitted from the first optical element 1 passes through the second optical element 2, the speckle of the laser beam is suppressed again.

[0075] The primary function of a diffuser is to provide a uniform surface light source for laser projection equipment. The working principle of a diffuser is to atomize the light source through refraction and reflection using a diffusing material, and to concentrate the light from a small angle onto the front surface to improve its brightness. For example, the structure of a diffuser typically consists of an antistatic coating layer, a substrate, and a diffusion layer from bottom to top. The substrate must be made of a material with high light transmittance, such as polyethylene terephthalate (PET), polycarbonate (PC), or polymethyl methacrylate (PMMA). Traditionally, diffusion layers mainly involve adding chemical particles to the substrate as scattering particles. However, in existing diffusers, these microparticles are dispersed between resin layers. As light passes through the diffusion layer, it continuously travels between two media with different refractive indices, resulting in numerous refraction, reflection, and scattering phenomena, thus creating the optical diffusion effect.

[0076] Furthermore, the first optical element 1 is disposed at the through-hole 103 of the first surface 101 of the substrate 10, serving as a dynamic diffuser. The first optical element 1 is connected to the elastic element 11 as a mover, and the vibration source 12 is connected to the substrate 10 as a stator. The vibration source 12 drives the first optical element 1 to vibrate in the plane (e.g., the XY horizontal plane) where the substrate 10 is located via the elastic element 11. The vibration frequency of the vibration source 12 is the same as the natural frequency of the spring oscillator. Thus, when the laser beam is incident on the first optical element 1, the vibration source 12 vibrates at this frequency, and the elastic element 11 drives the first optical element 1 to generate resonance at the same frequency, thereby suppressing the speckle of the laser beam. The natural frequency of the spring oscillator vibrating in the plane where the substrate 10 is located can be obtained through simulation analysis, and it is related to factors such as the mass, elastic modulus, and structure of the spring oscillator. Based on the natural frequency of the spring oscillator obtained from the simulation, and then applying the corresponding drive to the oscillator 12, the oscillator 12 can output the corresponding vibration frequency when it vibrates in the plane where the substrate 10 is located, thereby causing the elastic element 11 to drive the first optical element 1 to vibrate in the plane where the substrate 10 is located at the natural frequency.

[0077] Because resonance itself is highly destructive, most technical solutions related to vibration aim to avoid it. However, the embodiments of this application utilize the principle that the vibration energy required under resonance conditions is minimal. That is, the vibration source 12 only needs a small amount of vibration energy to enable the elastic element 11 to drive the first optical element 1 to generate a large amount of vibration, thereby improving the speckle reduction effect.

[0078] The second optical element 2 is disposed at the through-hole 103 on the second surface 102 of the substrate 10, and is also located in the optical path of the laser beam. The second optical element 2 is a static diffuser. The laser beam emitted from the first optical element 1 exits after passing through the second optical element 2. The second optical element 2 can suppress the speckle of the laser beam for the second time before entering the subsequent optical path. The subsequent optical path includes, but is not limited to, a homogenizing assembly, a lens assembly, an image display chip, and a lens.

[0079] Furthermore, the system oscillator of a traditional laser speckle eliminator is the spring oscillator of the oscillator source 12, which is an active vibration mode. The system oscillator only vibrates when the vibration frequency of the oscillator source 12 is close to or equal to the natural frequency of the overall system oscillator, resulting in high energy consumption. In contrast, the oscillator source 12 in this embodiment vibrates independently and is unrelated to the oscillator of the overall system, which is a passive vibration mode, thus significantly reducing power consumption. Simultaneously, the elastic element 11 of the spring oscillator is sleeved on the outer periphery of the first optical element 1. One end of the elastic element 11 is connected to the first optical element 1, and the other end is connected to the substrate 10. The structure is very simple, requiring no electromagnetic system, and the overall assembly method is simple, allowing for a small size and reducing manufacturing costs.

[0080] The laser speckle suppression device and laser projection equipment provided in this application embodiment include a substrate 10, a first optical element 1, an elastic element 11, a vibration source 12, and a second optical element 2. The substrate 10 has a first surface 101 and a second surface 102 disposed opposite to each other, and the substrate 10 includes a through hole 103 penetrating the first surface 101 and the second surface 102. The first optical element 1 is disposed at the through hole 103 and is used to transmit a laser beam. The elastic element 11 is sleeved on the outer periphery of the first optical element 1, one end of the elastic element 11 is connected to the first optical element 1, and the other end is connected to the substrate 10. The vibration source 12 is connected to the substrate 10, and the vibration source 10 drives the first optical element 1 to vibrate within the through hole 103 through the elastic element 11. The first optical element 1 and the elastic element 11 form a spring oscillator, and the vibration frequency of the vibration source 12 is close to or the same as the natural frequency of the spring oscillator. The second optical element 2 is located in the optical path of the laser beam, and the laser beam suppresses the speckle twice after passing through the first optical element 1 and the second optical element 2. Therefore, by combining the dynamic first optical element 1 and the static second optical element 2, the speckle of the laser beam is suppressed twice, effectively improving the speckle elimination effect of the laser beam. At the same time, the first optical element 1 is connected to the elastic element 11, and the vibration source 12 is connected to the substrate 10. By setting the vibration frequency of the vibration source 12 in the plane of the substrate 10 to be close to or the same as the natural frequency of the spring oscillator, the resonance principle is used so that the vibration source only needs a small amount of vibration energy to drive the first optical element 1 to generate a large amount of vibration through the elastic element. The power consumption is low, and the structure is simple, the size is small, and the manufacturing cost is low.

[0081] In some embodiments, the elastic element 11 includes N coils of springs 111 arranged in a coplanar manner, with adjacent coils of springs 111 connected by a connecting portion 112, wherein N≥2.

[0082] As shown in Figure 6, the elastic element 11 is a planar coil spring, manufactured by laser etching or laser engraving on a planar plate. The planar plate can be a metal plate such as steel, copper, or nickel. The elastic element 11 includes at least two coils of spring 111 arranged coplanarly, such as 3, 4, 5, or more coils. Increasing or decreasing the number of coils of spring 111 can adjust the resonant frequency of the first optical element 1 in the plane of the substrate 10 (e.g., the XY horizontal plane). The cross-section of the spring 111 is rectangular. If the elastic element 11 is manufactured by laser engraving on the planar plate, the ratio of the width to the depth of the cross-section of the spring 111 is generally 1:1; if the elastic element 11 is manufactured by laser etching on the planar plate, the ratio of the width to the depth of the cross-section of the spring 111 is generally greater than or equal to 0.5. In addition, the cross-sectional shape and size of the connecting part 112 can be the same as that of the spring 111, simplifying the manufacturing process.

[0083] It can be understood that the elastic member 11 in the embodiments of the present application can also be a spiral spring. The vibration source 12 drives the first optical element 1 to vibrate in any one of the XY plane, YZ plane, and XZ plane through the elastic member 11, achieving the effect of suppressing the speckle of the laser beam.

[0084] In addition, as shown in FIG. 6, during the vibration of the first optical element 1 in the XY horizontal plane, it is easy to occur collision interference between two adjacent coils of the spring 111. To solve this problem, two adjacent coils of the spring 111 are connected by a connecting portion 112. The setting of the connecting portion 112 can improve the overall stiffness of the elastic member 11, making the entire system stable during vibration and avoiding generating noise due to mutual collision.

[0085] Furthermore, two connecting portions 112 symmetrically distributed along the first direction are provided between the i-th coil of the spring 111 and the (i + 1)-th coil of the spring 111, and two connecting portions 112 symmetrically distributed along the second direction are provided between the (i + 1)-th coil of the spring 111 and the (i + 2)-th coil of the spring 111. The first direction X and the second direction Y are perpendicular to each other, where 1 ≤ i < N and i is an odd number.

[0086] As shown in FIG. 6, the first direction X and the second direction Y are perpendicular to each other. The elastic member 11 includes 5 coils of springs 111 arranged in the same plane. Two connecting portions 112 are provided between two adjacent coils of the spring 111, and there are a total of 12 connecting portions 112. The distribution of each coil of the spring 111 and the connecting portion 112 from the inside to the outside is as follows: Two connecting portions 112 symmetrically distributed along the first direction X are provided between the first coil of the spring 111 and the second coil of the spring 111, two connecting portions 112 symmetrically distributed along the second direction Y are provided between the second coil of the spring 111 and the third coil of the spring 111, two connecting portions 112 symmetrically distributed along the first direction X are provided between the third coil of the spring 111 and the fourth coil of the spring 111, and two connecting portions 112 symmetrically distributed along the second direction Y are provided between the fourth coil of the spring 111 and the fifth coil of the spring 111. The first coil of the spring can also be fixedly connected to the first optical element 1 by means of glue, fasteners, etc., and the N-th coil of the spring can also be fixedly connected to the substrate 10 by means of glue, fasteners, etc. In this way, when the elastic member 11 vibrates in the X direction or Y direction in the horizontal plane, due to the existence of the connecting portion 112, a stable gap can be maintained between two adjacent coils of the spring 111 without collision interference.

[0087] Furthermore, by reducing or increasing the number of coils in the spring 111, the elastic element 11 can adjust the different resonant frequencies of the spring oscillator in the XY horizontal plane vibration modes. The stress on the elastic element 11 varies at different positions under external force, and the displacement is also greatest at the position of maximum stress. In this embodiment, when the spring oscillator resonates in the XY horizontal plane vibration modes, the maximum stress value corresponding to the position of maximum displacement of the elastic element 11 is relatively small, which can effectively increase the fatigue life of the elastic element 11.

[0088] It is understandable that the number of connecting parts 112 between two adjacent coils of spring 111 is an even number, and is not limited to the two shown in the figure. It can also be four, six, etc., which will not be elaborated further.

[0089] In some embodiments, the first coil of spring 111 is connected to the first optical element 1 via a connecting portion 112, and the Nth coil of spring 111 is connected to the substrate 10 via a connecting portion 112. Specifically, as shown in FIG6, the first direction X and the second direction Y are perpendicular to each other. Assuming that two connecting portions 112 symmetrically distributed along the first direction X are provided between the first coil of spring 111 and the second coil of spring 111, then two connecting portions 112 symmetrically distributed along the second direction Y are provided between the first coil of spring 111 and the first optical element 1. Assuming that two connecting portions 112 symmetrically distributed along the second direction Y are provided between the (N-1)th coil of spring 111 and the Nth coil of spring 111, then two connecting portions 112 symmetrically distributed along the first direction X are provided between the Nth coil of spring 111 and the substrate 10.

[0090] The multi-turn spring 111 and multiple connecting parts 112 of the elastic element 11 can be integrally formed. The connecting parts 112 can be bonded to the first optical element 1 and to the substrate 10 by adhesive or by fasteners such as screws. In this way, the elasticity of the elastic element 11 itself can be fully utilized to adjust the resonant frequency of the spring oscillator in the XY horizontal plane vibration mode, while reducing the number of turns of the spring 111 and reducing the space occupied by the product.

[0091] In some embodiments, the number of elastic elements 11 is at least two, and the at least two elastic elements 11 are spaced apart along a direction perpendicular to the diffusion surface of the first optical element 1. This arrangement allows for the acquisition of the natural frequencies of the spring oscillator in various different modes, thereby determining the vibration frequency of the vibration source 12.

[0092] In one example, as shown in Figure 3, two elastic elements 11 are spaced apart along a direction perpendicular to the first optical element 1, and the first optical element 1 may be disposed on the moving part of only one of the elastic elements 11. In another example, each elastic element 11 is connected to the first optical element 1.

[0093] Furthermore, when the first optical element 1 resonates with the vibration source 12 through the elastic element 11, theoretically there are an infinite number of resonant modes. However, in practice, the resonant frequencies of the desired and unwanted modes are often very close. In this case, one or more sets of adjacent elastic elements 11 in the resonant modes will collide and interfere during resonance, which not only makes the system unstable but also generates a lot of noise. In practical applications, the system will exhibit unstable vibrations.

[0094] Therefore, in this embodiment, a support member is provided between the two connecting portions 112 corresponding to two adjacent elastic elements 11. The support member connects the two connecting portions 112 of the two adjacent elastic elements 11 together, so that when the system vibrates in a mode perpendicular to the substrate 10, the stiffness of the system changes significantly. When it is excited to resonate again at the original vibration frequency, the mode will not resonate in the Z direction, thereby eliminating unwanted vibration modes. This allows the first optical element 1 to vibrate in the XY plane in an ideal stable mode, eliminating resonance noise.

[0095] In some embodiments, a first groove 104 is provided on the first surface 101 of the substrate 10 around the through hole 103, and the first optical element 1 and the elastic member 11 are disposed in the first groove 104. As shown in FIG3, the first groove 104 is provided on the first surface 101 of the substrate 10 around the through hole 103 to accommodate the first optical element 1 and the elastic member 11. This arrangement can reduce the thickness of the laser speckle suppression device, which is beneficial to realizing the miniaturization design of the laser speckle suppression device.

[0096] In some embodiments, a second groove 105 is provided on the second surface 102 of the substrate 101. The second groove 105 is not connected to the through hole 103, and the vibration source 12 is disposed in the second groove 105. As shown in FIG3, the second surface 102 of the substrate 101 is provided with a second groove 105 for accommodating the vibration source 12. The second groove 105 can further reduce the thickness of the laser speckle suppression device, which is more conducive to realizing the miniaturization design of the laser speckle suppression device. The second groove 105 is not connected to the through hole 103, which can physically isolate the vibration source 12 from the spring oscillator, reducing the interference when the vibration source and the spring oscillator resonate.

[0097] Optionally, the shape of the first optical element 1 can be any one of a circle, an ellipse, and a polygon, and the shape of the elastic element 11 is consistent with the shape of the first optical element 1. As shown in Figures 2 to 5, the shape of the first optical element 1 is rectangular, and the elastic element 11 is fitted onto the outer periphery of the first optical element 1, and its shape is also rectangular. The shape of the first optical element 1 can also be a circle, an ellipse, or a polygon. Polygons include triangles, squares, rhombuses, trapezoids, pentagons, etc., which will not be elaborated further.

[0098] In addition, there can be multiple first optical elements 1, which are spaced apart along the optical path. Correspondingly, there can also be more vibration sources 12, which can further improve the speckle elimination effect of the laser beam, depending on the specific application.

[0099] In some embodiments, the laser speckle suppression device further includes a circuit board 13, which is connected to the substrate 10 via a fastener 15, and the circuit board 13 is electrically connected to the pads of the oscillator 12 via a compression spring 14.

[0100] As shown in Figure 3, the circuit board 13 is used to control the start and stop of the vibration source 12. Optionally, the circuit board 13 is a flexible circuit board. On the one hand, the flexible circuit board is easy to bend, reducing the space occupied; on the other hand, it will not be damaged by collision during vibration, thus improving the reliability of the vibration source 12.

[0101] Furthermore, the circuit board 13 is connected to the substrate 10 via two fasteners 15, achieving a mechanical connection between the circuit board 13 and the substrate 10. In addition, to prevent the solder joints of the circuit board 13 from loosening or falling off during the vibration of the vibration source 12, the circuit board 13 is electrically connected to the solder pads of the vibration source 12 via a compression spring 14, further improving the reliability of the vibration source 12.

[0102] It is understandable that circuit board 13 can also be a rigid printed circuit board, depending on the application, which will not be elaborated further.

[0103] As shown in Figure 7, this application embodiment also provides a laser speckle suppression device, which is similar in structure to the laser speckle suppression devices shown in Figures 1 to 6, except that the second optical element 2 is a reflector.

[0104] Specifically, after the laser beam passes through the first optical element 1, the speckle of the laser beam is suppressed for the first time. The laser beam emitted from the first optical element 1 is reflected after reaching the second optical element 2. The reflected laser beam passes through the first optical element 1 again and is emitted, and the speckle of the laser beam is suppressed again before entering the subsequent optical path.

[0105] Since the laser beam returns to the first optical element 1 after being transmitted through the first optical element 1 and reflected by the second optical element 2, the optical path is folded, so that the subsequent optical path is located on the side of the first optical element 1 facing the laser source. This can reduce the space occupied by the overall optical path, which in turn helps to reduce the size of the laser speckle suppression device.

[0106] Furthermore, the second optical element 2 has a reflecting surface, which can be a plane or a curved surface. The concave surface can be any of a sphere, an even-order aspherical surface, or a freeform surface. The even-order aspherical surface can be any of a hyperboloid, a parabola, or an ellipsoid.

[0107] Optionally, a reflective film is provided on the reflective surface. The reflective film can be made of, for example, a high-reflectivity metal reflective film or a dielectric reflective film, and is formed on the reflective surface of the second optical element 2 by spraying or coating to improve the reflectivity of the second optical element 2.

[0108] Optionally, when the reflecting surface of the second optical element 2 is a plane, the angle between the optical axis of the incident light beam that first incident on the first optical element 1 and the surface of the first optical element 1 is in the range of 45° to 90°, so that the laser beam emitted from the first optical element 1 is reflected back to the first optical element 1 as much as possible after reaching the reflecting surface.

[0109] Optionally, when the reflecting surface of the second optical element 2 is curved, the optical axis of the incident light ray that first enters the first optical element 1 is parallel to the normal of the second optical element 2. This reduces the overall volume of the laser speckle suppression device while ensuring that the laser beam emitted from the first optical element 1 is reflected back to the first optical element 1 as much as possible after reaching the reflecting surface.

[0110] As shown in Figure 8, this application embodiment also provides a laser speckle suppression device, which is similar in structure to the laser speckle suppression device shown in Figure 7. The difference is that there are two second optical elements 2. The normals of the reflecting surfaces of the two second optical elements 2 are arranged perpendicular to each other. The angle formed between the normal of the reflecting surface of one second optical element 2 and the surface of the first optical element 1 is in the range of 45°±15°. The angle formed between the reflecting surface of the other second optical element 2 and the surface of the first optical element 1 is in the range of 45°±15°.

[0111] Furthermore, when the laser beam enters the first optical element 1 at an incident angle parallel to the normal of the first optical element 1, the speckle of the laser beam is suppressed for the first time. Then, the laser beam emitted from the first optical element 1 reaches the reflecting surface of one of the second optical elements 2 at an incident angle of 0°. After reflection, it reaches the reflecting surface of the other second optical element 2. After reflection, it returns to the first optical element 1 at an incident angle parallel to the normal of the first optical element 1, and the speckle of the laser beam is suppressed for the second time. Then it enters the subsequent optical path.

[0112] Since the laser beam can be incident parallel to the first optical element 1 and one of the second optical elements 2, and exit parallel from the other second optical element 2, not only can the laser beam exiting from the first optical element 1 be reflected back to the first optical element 1 as much as possible after reaching the reflecting surface, but the overall volume of the laser speckle suppression device is also reduced.

[0113] In addition, this application provides a laser projection device, including a laser source and a laser speckle suppression device as described above. The laser source is used to emit a laser beam, and the laser speckle suppression device is disposed in the optical path of the laser beam. When applied to a laser projection device, this laser speckle suppression device can effectively improve the speckle problem of the laser beam, enhance the display effect of the laser projection device, and is small in size and low in cost.

[0114] In addition, to suppress the speckle effect of laser light, some related technologies employ a diffuser wheel. The working principle involves a rotating motor driving the diffuser wheel to rotate at high speed. When the laser passes through the diffuser wheel, it produces beams at different angles. The superposition of these beams creates the visual effect of speckle elimination. However, because the rotating motor itself cannot be made very small, its size is large, resulting in a large diffuser wheel area and a larger overall optical path volume. Larger diffuser plates increase cost; high-speed rotation causes friction and chipping from the diffuser wheel, which can easily jam the rotor and burn out the motor.

[0115] Among related technologies are laser speckle reduction (LSR) devices, which work by using a voice coil motor to vibrate a diffuser in the same way through horizontal vibration, thereby eliminating laser speckle. However, achieving horizontal vibration requires a combination of electromagnetic and spring systems, as well as a support structure, making the overall structure relatively complex with many components, which limits the reduction of production costs.

[0116] In addition, some deformable mirror solutions in related technologies utilize mirrors that can undergo microscopic deformation to reflect laser beams, thereby changing the phase of the beam to eliminate speckle. However, by using the piezoelectric principle to deform each micro-unit of the mirror, the material and production costs are extremely high, making it suitable only for high-end optical equipment and prohibiting its mass production.

[0117] Therefore, this application provides a laser speckle suppression device, including a diffuser 4, an elastic element 11, and a vibration source 12. The diffuser 4 can be used as the first optical element 1 in the other embodiments described above, or it can be used as other elements, and there is no limitation thereto.

[0118] As shown in Figures 9 to 11, the diffuser 4 is used to transmit the laser beam. The main function of the diffuser 4 is to provide a uniform surface light source for the laser projection device. The working principle of the diffuser is to atomize the light source through refraction and reflection by the diffusing material, and to concentrate the light from a small angle onto the front to improve the brightness of the front. Exemplarily, the structure of the diffuser 4, from bottom to top, is usually an antistatic coating layer, a substrate, and a diffusion layer. The substrate needs to be a material with high light transmittance, such as polyethylene terephthalate (PET), polycarbonate (PC), or polymethyl methacrylate (PMMA). Generally, traditional diffusion layers mainly add chemical particles to the substrate as scattering particles, while in existing diffusers, the microparticles are dispersed between the resin layers. When light passes through the diffusion layer, it continuously passes through two media with different refractive indices, and at the same time, many refraction, reflection, and scattering phenomena occur, resulting in the optical diffusion effect.

[0119] The elastic element 11 is disposed on the outer periphery of the diffuser plate 4, and the diffuser plate 4 and the elastic element 11 form a spring oscillator. The elastic element 11 includes a moving part 113, an elastic part 110 and a fixing part 114 arranged sequentially from the inside to the outside. The moving part 113 is connected to the diffuser plate 4, one end of the elastic part 110 is connected to the moving part 113, and the other end of the elastic part 110 is connected to the fixing part 114.

[0120] The vibration source 12 is connected to the fixing part 114. The vibration source 12 and the spring oscillator resonate in a preset mode, causing the diffuser 4 to vibrate in a preset direction to suppress the speckle of the laser beam.

[0121] In this embodiment, the diffuser 4 and the elastic element 11 form a spring oscillator. The preset mode can be the mode in which the spring oscillator vibrates in the XY horizontal plane, or it can be the mode in the YZ plane or the XZ plane. When the vibration source 12 and the spring oscillator resonate in the preset mode, the vibration frequency of the vibration source 12 is close to or the same as the natural frequency of the spring oscillator. Thus, when the vibration source 12 vibrates at this vibration frequency, the elastic element 11 will drive the diffuser 4 to generate resonance at the same frequency.

[0122] As shown in Figures 10 and 11, taking the vibration mode of a spring oscillator in the XY horizontal plane as an example, the natural frequency of the spring oscillator when vibrating along the X or Y direction is related to factors such as the mass, elastic modulus, and structure of the spring oscillator. Based on simulation analysis, the natural frequency of the spring oscillator is obtained. Then, by applying a corresponding drive along the X or Y direction to the vibration source 12, the vibration source 12 can output the corresponding vibration frequency when vibrating in the XY horizontal plane. This causes the elastic element 11 to drive the diffuser 4 to vibrate along the X or Y direction at the natural frequency, thereby achieving a resonance effect.

[0123] Because resonance itself is highly destructive, most vibration-related technical solutions aim to avoid it. However, this application embodiment utilizes the principle that the vibration energy required under resonance conditions is minimal. This allows the vibration source 12 to generate a large vibration by driving the diffuser 4 with the elastic element 11, even with only a small amount of vibration energy. The elastic part 110 of the elastic element 11 amplifies or reduces the vibration of the vibration source 12 to meet the gain requirements of the diffuser 4, thereby improving the speckle reduction effect.

[0124] Furthermore, the system oscillator of a traditional LSR device is the oscillator of the oscillator source 12, which is an active vibration mode. The system oscillator only vibrates when the vibration frequency of the oscillator source 12 is close to or equal to the natural frequency of the overall system oscillator, resulting in high energy consumption. In contrast, the oscillator source 12 in this embodiment vibrates independently and is unrelated to the vibration of the overall system, which is a passive vibration mode, thus significantly reducing power consumption. At the same time, the structure of the elastic element 11 is very simple. It is connected to the diffuser plate 4 through the moving part 113 and to the oscillator source 12 through the fixing part 114. It does not require an electromagnetic system, the overall assembly method is simple, and the size can be made very small, which helps to reduce manufacturing costs.

[0125] It should be noted that, in this article, "close to" means that the vibration frequency of the vibration source 12 differs from the natural frequency of the spring oscillator in the preset mode by no more than ±10%. The laser speckle suppression device provided in this application embodiment includes a diffuser 4, an elastic element 11, and a vibration source 12. The elastic element 11 includes a moving part 113, an elastic part 110, and a fixed part 114 arranged sequentially from the inside to the outside. By connecting the diffuser 4 to the moving part 113 and the vibration source 12 to the fixed part 114, the diffuser 4 and the elastic element 11 form a spring oscillator. The vibration source 12 and the spring oscillator resonate in the preset mode, causing the diffuser 4 to vibrate in the preset direction to suppress the speckle of the laser beam. Thus, by utilizing the resonance principle, the vibration source 12 only needs a small amount of vibration energy to drive the diffuser 4 to generate a large amount of vibration through the elastic element 11. The power consumption is low, and the structure is simple, the size is small, and the manufacturing cost is low.

[0126] In some embodiments, the elastic part 110 is a flexible ring structure. The flexible ring structure is made of rubber or silicone. The inner ring of the flexible ring structure is connected to the diffuser 4 via the moving part 113, and the outer ring of the flexible ring structure is connected to the vibration source 12 via the fixing part 114.

[0127] In some embodiments, the elastic part 110 is a spring. Optionally, the elastic part 110 is a helical spring. The vibration source 12 drives the diffusion sheet 4 to vibrate in any one of the XY plane, YZ plane, and XZ plane through the elastic member 11, achieving the effect of suppressing the speckle of the laser beam. Optionally, the elastic part 110 is a flat spiral spring, which is made by using a laser etching or laser engraving process on a flat plate. The flat plate can be a metal plate such as a steel plate, a copper plate, or a nickel plate. The vibration source 12 drives the diffusion sheet 4 to vibrate in this plane. In some embodiments, the elastic part 110 includes N coils of springs 111 arranged coplanarly, and N≥2; the elastic member 11 further includes a connecting part 112. Adjacent coils of springs 111 are connected by the connecting part 112. The innermost coil of spring 111 is connected to the moving part 113 by the connecting part 112, and the outermost coil of spring 111 is connected to the fixed part 114 by the connecting part 112.

[0128] As shown in FIG. 10, the elastic part 110 is a flat spiral spring. The elastic part 110 includes at least two coils of springs 111 (which can also be called spring wires) arranged coplanarly, such as 3 coils, 4 coils, 5 coils or more coils of springs 111. In this way, the natural frequency of the spring oscillator in the XY horizontal plane vibration mode can be lower, and the elastic coefficient is smaller. The vibration source 12 only needs a smaller vibration energy to drive the diffusion sheet 4 to generate a larger vibration amount through the elastic member 11. By increasing or decreasing the number of coils of the spring 111, the resonance frequency in the XY horizontal plane vibration mode can be adjusted.

[0129] Further, as shown by the dashed box in FIG. 12, during the vibration of the diffusion sheet 4 in the horizontal plane, collisions and interferences are likely to occur between adjacent coils of springs 111, between the innermost coil of spring 111 and the moving part 113, and between the outermost coil of spring 111 and the fixed part 114. To solve this problem, as shown in FIG. 13, adjacent coils of springs 111 are connected by the connecting part 112. The innermost coil of spring 111 is connected to the moving part 113 by the connecting part 112, and the outermost coil of spring 111 is connected to the fixed part 114 by the connecting part 112. The setting of the connecting part 112 can increase the overall stiffness of the elastic sheet 2, keep the whole system stable during vibration, and avoid generating noise due to mutual collision.

[0130] Further, two connecting parts 112 symmetrically distributed along the first direction are provided between the i-th coil of spring 111 and the (i + 1)-th coil of spring 111, and two connecting parts 112 symmetrically distributed along the second direction are provided between the (i + 1)-th coil of spring 11 and the (i + 2)-th coil of spring 111. The first direction X and the second direction Y are perpendicular to each other, where 1≤i<N and i is an odd number.

[0131] As shown in FIG. 14, the elastic part 110 of the elastic member 11 includes five co-planar springs 111. There are two connecting parts 112 respectively provided between two adjacent springs 111, between the innermost spring 111 and the moving part 113, and between the outermost spring 111 and the fixed part 114, with a total of 12 connecting parts 112. The distribution of the springs 111 and the connecting parts 112 from the inside to the outside is as follows: There are two connecting parts 112 symmetrically distributed along the first direction X between the first spring 111 and the second spring 111, two connecting parts symmetrically distributed along the second direction Y between the second spring 111 and the third spring 111, two connecting parts symmetrically distributed along the first direction X between the third spring 111 and the fourth spring 111, and two connecting parts symmetrically distributed along the second direction Y between the fourth spring 111 and the fifth spring 111. The first spring 111 can also be fixedly connected to the diffusion sheet 4 by means of glue, fasteners, etc., and the Nth spring 111 can also be fixedly connected to the fixed part 114 by means of glue, fasteners, etc. In this way, when the elastic member 11 vibrates in the X direction or the Y direction in the horizontal plane, due to the existence of the connecting parts 112, a stable gap can be maintained between two adjacent springs 111 without collision interference.

[0132] In addition, by reducing or increasing the number of turns of the spring 111, the elastic member 11 can adjust its different resonance frequencies in the XY horizontal plane vibration mode. The stress on the elastic member 11 at different positions under an external force is different, and the displacement at the position of the maximum stress value is also the largest. In this embodiment, when the elastic member 11 of the spring oscillator resonates in the XY horizontal plane vibration mode, the maximum stress value corresponding to the position with the largest movement displacement is relatively small, which can effectively increase the fatigue life of the elastic member 11.

[0133] It can be understood that the number of the connecting parts 112 respectively provided between two adjacent springs 111, between the innermost spring 111 and the moving part 113, and between the outermost spring 111 and the fixed part 114 is an even number, not limited to two as shown in the figure, and can also be four, six, etc., which will not be elaborated here.

[0134] In some embodiments, the gap d between two adjacent springs 111 satisfies the following condition: 0.5mm < d < 2mm. This gap d can not only ensure that there is no collision interference between two adjacent springs 111 during vibration, but also ensure that the diffusion sheet 4 vibrates in an ideal stable mode.

[0135] In one example, according to the simulation analysis, when the natural frequency of the elastic member 11 is 200 HZ, the number of turns of the spring 111 of the elastic part 110 is 5 turns, and the gap d between two adjacent turns of the spring 111 is 1 mm. It should be noted that the natural frequency of the elastic member 11 can also be other values between 100 HZ and 1000 HZ, the number of turns of the spring 111 can be any number of turns between 2 and 20 turns, and the value range of the gap d between two adjacent turns of the spring 111 is 0.5 mm < d < 2 mm, which is determined according to the actual application scenario and testing, and will not be elaborated here.

[0136] In some embodiments, the cross-section of the spring 111 is rectangular, and the ratio of its width to depth is 0.5 - 1.

[0137] The size of the cross-section of the spring 111 is determined by the manufacturing process. If the elastic member 11 is made by laser engraving on a flat plate, the ratio of the width to the depth of the cross-section of the spring 111 is generally 1:1; if the elastic part 110 is made by laser etching on a flat plate, the ratio of the width to the depth of the cross-section of the spring 111 is generally greater than or equal to 0.5. In addition, the cross-sectional shape and size of the connecting part 112 can be the same as those of the spring 111, which simplifies the manufacturing process flow.

[0138] In some embodiments, the shape of the diffusion sheet 4 is any one of a circle, an ellipse, and a polygon. The shape of the elastic member 11 is consistent with the shape of the diffusion sheet 4. As shown in FIG. 14, the shape of the diffusion sheet 4 is rectangular, and the elastic member 11 is sleeved on the outer peripheral side of the diffusion sheet 4, and its shape is also rectangular. As shown in FIG. 15, the shape of the diffusion sheet 4 is circular, and the elastic member 11 is sleeved on the outer peripheral side of the diffusion sheet 4, and its shape is also circular. The shape of the diffusion sheet 4 can also be an ellipse or a polygon. The polygon includes a triangle, a square, a rhombus, a trapezoid, a pentagon, etc., and will not be elaborated here.

[0139] Further, the moving part 113 is adhesively connected to the edge of the diffusion sheet 4. Since the weight of the diffusion sheet 4 is small, it can be adhesively connected to the moving part 113 of the elastic member 11 through a colloid. The connection method is simple and reliable, reducing metal parts such as screws, and avoiding failure due to the脱落 of screws, etc. during the vibration of the diffusion sheet 4, thereby improving the reliability of suppressing laser speckle.

[0140] Further, the vibration source 12 is arranged on the plane where the fixing part 114 is located. Optionally, the vibration source 12 is a linear vibration motor or a rotary motor, and can also be other forms of vibration devices, such as including but not limited to a rotating fan, a fluorescent wheel, and / or a color filter wheel, etc. Arranging the vibration source 12 on the plane where the fixing part 114 is located can directly transfer the vibration energy to the elastic part 110 of the elastic member 11 along the shortest path, reducing the loss of vibration energy.

[0141] In one example, the fixing part 114 is a flat plate structure with a certain thickness, which differs in thickness from the moving part 113 and the elastic part of the elastic element 11. The structural strength and stiffness of the fixing part 114 meet the vibration requirements of the vibration source 12. In another example, the laser speckle suppression device also includes a fixing bracket connected to the fixing part 114. The fixing part 114 and the moving part 113 and the elastic part of the elastic element 11 are made of the same plate or sheet-like structural parts, simplifying the manufacturing process of the elastic element 11 and reducing manufacturing costs. At the same time, the fixing part 114 itself has lower structural strength and stiffness, and by connecting it to the fixing bracket, the vibration requirements of the vibration source 12 can be met.

[0142] In some embodiments, the number of elastic elements 11 is at least two, and the at least two elastic elements 11 are spaced apart along a direction perpendicular to the diffuser 4. This arrangement allows for the acquisition of the natural frequencies of the elastic elements 11 in various modes, thereby determining the vibration frequency of the vibration source 12. In one example, as shown in FIG16, three elastic elements 11 are spaced apart along a direction Z perpendicular to the diffuser 4. The diffuser 4 may be disposed only on the moving part 113 of one of the elastic elements 11, and the vibration source 12 may be disposed only on the fixed part 114 of that elastic element 11. In another example, a diffuser 4 is disposed on the moving part 113 of each elastic element 2, and correspondingly, a vibration source 12 is disposed on the fixed part 114 of each elastic element 11. In yet another example, a diffuser 4 is disposed on the moving part 113 of some elastic elements 2, and a vibration source 12 is disposed on the fixed part 114 of some elastic elements 11; the specific application depends on the application and will not be elaborated further.

[0143] Furthermore, when the spring oscillator resonates with the vibration source 12, there are theoretically an infinite number of resonant modes. However, in practice, the resonant frequencies of the desired mode and the unwanted mode are often very close. In this way, the system will experience unstable vibrations in practical applications.

[0144] As shown in the dashed box in Figure 17, when multiple elastic elements 11 are spaced apart along the direction Z perpendicular to the diffuser plate 4, one or more sets of adjacent elastic elements 11's elastic parts 110 will collide and interfere during resonance, which not only makes the system unstable, but also generates a lot of noise.

[0145] Therefore, in this embodiment, a support assembly 3 is provided between the elastic portions 110 of two adjacent elastic members 11. The support assembly 3 connects the elastic portions 110 of the two adjacent elastic members 11 together in the Z direction, so that the stiffness of the system changes significantly in this mode. When it is excited to resonate again at the original vibration frequency, this mode will not resonate, thereby eliminating unwanted vibration modes. This allows the diffuser 4 to vibrate in the XY plane in an ideal stable mode, eliminating resonance noise.

[0146] Specifically, the support assembly 3 includes at least a first support member 31 connecting the connecting portions 112 of two adjacent elastic elements 11. As shown in Figures 16 and 18, when the elastic element 11 is rectangular, the connecting portions 112 and corners of the elastic parts 110 are relatively weak in stiffness and are prone to breakage or other damage during vibration. Therefore, the support assembly 3 includes a first support member 31 connecting the connecting portions 112 of two adjacent elastic elements 11, and a second support member 32 connecting the corners of two adjacent elastic elements 11. The first support member 31 and the second support member 32 can change the overall stiffness of the elastic system composed of multiple elastic elements 11. When it is excited to resonate at the original vibration frequency, the mode along the Z direction will not resonate, thereby eliminating unwanted vibration modes and allowing the diffuser 4 to vibrate in the XY plane in an ideal stable mode, thus eliminating resonance noise.

[0147] It is understandable that when the elastic element 11 is circular, the support assembly 3 only includes the first support element 31 that connects the connecting parts 112 of two adjacent elastic elements 11, so as to change the overall stiffness of the elastic system composed of multiple elastic elements 11, so that the diffuser 4 vibrates in an ideal stable mode and eliminates resonance noise.

[0148] In addition, the support components 3 provided between the connecting parts 112 of two adjacent elastic elements 11 can be connected by glue, plastic or metal parts, or by insert injection molding to achieve the integrated connection of multiple elastic elements 11.

[0149] Further, the distance between two adjacent elastic members 11 is 0.5 mm to 1 mm. This distance can ensure that there is no collision interference between two adjacent elastic members 11 during vibration, and can also ensure that the diffusion sheet 4 vibrates in an ideal stable mode. In one example, according to simulation analysis, when three elastic members 11 are arranged at intervals in a direction perpendicular to the diffusion sheet 4 and the natural frequency of the elastic member 11 is 200 HZ, the distance between two adjacent elastic members 11 is 0.8 mm. It should be noted that the natural frequency of the elastic member 11 can also be other values between 100 HZ and 1000 HZ, the number of elastic members 11 can be more, and the value range of the gap d between two adjacent turns of the spring 111 is 0.5 mm < d < 2 mm, which is determined according to the actual application scenario and test, and will not be elaborated here.

[0150] In addition, an embodiment of the present application provides a laser projection device, including a laser source and the laser speckle suppression device as described above. The laser source is used to emit a laser beam, and the laser speckle suppression device is arranged on the optical path of the laser beam. The application of this laser speckle suppression device in a laser projection device can effectively improve the speckle problem of the laser beam and enhance the display effect of the laser projection device.

[0151] It should be noted that the phrases such as "one embodiment", "an embodiment", "exemplary embodiment", "some embodiments", etc. mentioned in the specification indicate that the described embodiments may include specific features, structures or characteristics, but not necessarily every embodiment includes such specific features, structures or characteristics. In addition, such phrases do not necessarily refer to the same embodiment. Moreover, when combining specific features, structures or characteristics with an embodiment, implementing such features, structures or characteristics in combination with other embodiments, whether explicitly or implicitly described, is within the knowledge scope of those skilled in the art.

[0152] It should be easily understood that the terms "on...", "above...", and "over..." in the present disclosure should be interpreted in the broadest manner, so that "on..." not only means "directly on something", but also includes the meaning of "on something" with intermediate features or layers therebetween, and "above..." or "over..." not only includes the meaning of "above or over something", but may also include the meaning of "above or over something" without intermediate features or layers therebetween (i.e., directly on something).

[0153] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90 degrees or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0154] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A laser speckle suppression device, characterized in that, Comprising: A substrate having a first surface and a second surface disposed opposite to each other, the substrate including a through-hole penetrating the first surface and the second surface; A first optical element disposed at the through-hole, the first optical element being configured to transmit a laser beam to perform a first suppression on the speckle of the laser beam; An elastic member, one end of which is connected to the first optical element and the other end of which is connected to the substrate; A vibration source connected to the substrate, the vibration source driving the first optical element to vibrate in the through-hole through the elastic member, wherein the first optical element and the elastic member form a spring oscillator, and the vibration frequency of the vibration source is close to or the same as the natural frequency of the spring oscillator to generate resonance with the spring oscillator; And A second optical element located in the optical path of the laser beam, configured to perform a second suppression on the speckle of the laser beam.

2. The laser speckle suppression device according to claim 1, characterized in that, The elastic member includes N coils of springs disposed coplanarly, and adjacent coils of springs are connected by connecting portions, where N≥2.

3. The laser speckle suppression device according to claim 2, characterized in that, Two of the connecting portions symmetrically distributed in a first direction are provided between the i-th coil of the spring and the (i + 1)-th coil of the spring, and two of the connecting portions symmetrically distributed in a second direction are provided between the (i + 1)-th coil of the spring and the (i + 2)-th coil of the spring, the first direction and the second direction being perpendicular to each other, where 1≤i<N and i is an odd number.

4. The laser speckle suppression device according to claim 1, characterized in that, The number of the elastic members is at least two, and at least two of the elastic members are spaced apart in a direction perpendicular to the diffusion surface of the first optical element.

5. The laser speckle suppression device according to claim 4, characterized in that, A support member is provided between two corresponding connecting portions of two adjacent elastic members.

6. The laser speckle suppression device according to any one of claims 1 to 5, wherein Both the first optical element and the second optical element are diffuser sheets. After the laser beam passes through the first optical element, a first suppression is performed on the speckle of the laser beam. The laser beam emitted from the first optical element passes through the second optical element and then exits, and the speckle of the laser beam is suppressed again.

7. The laser speckle suppression device according to any one of claims 1 to 5, characterized in that, The first optical element is a diffuser sheet, and the second optical element is a mirror. After the laser beam passes through the first optical element, a first suppression is performed on the speckle of the laser beam. The laser beam emitted from the first optical element is reflected after reaching the second optical element, and the reflected laser beam passes through the first optical element again and then exits, and the speckle of the laser beam is suppressed again.

8. A laser speckle suppression device, characterized in that, Comprising: A substrate having a through-hole; A first optical element disposed at the through-hole; An elastic member, one end of which is connected to the first optical element and the other end of which is connected to the substrate; A vibration source connected to the substrate, the vibration source driving the first optical element to vibrate in the through-hole through the elastic member, wherein the first optical element and the elastic member form a spring oscillator, and the vibration frequency of the vibration source is close to or the same as the natural frequency of the spring oscillator to generate resonance with the spring oscillator.

9. The laser speckle suppression device according to claim 8, characterized in that, The elastic member includes N coils of springs disposed coplanarly, and adjacent coils of springs are connected by connecting portions, where N≥2.

10. The laser speckle suppression device according to claim 9, characterized in that, Between the i-th coil of the spring and the (i + 1)-th coil of the spring, there are two connection parts symmetrically distributed along the first direction. Between the (i + 1)-th coil of the spring and the (i + 2)-th coil of the spring, there are two connection parts symmetrically distributed along the second direction. The first direction and the second direction are perpendicular to each other, where 1 ≤ i < N and i is odd.

11. The laser speckle suppression device according to claim 8, characterized in that, The number of the elastic members is at least two, and at least two of the elastic members are spaced apart along a direction perpendicular to the diffusion surface of the first optical element.

12. The laser speckle suppression device according to claim 11, characterized in that, There is a support member between two connection parts corresponding to two adjacent elastic members.

13. The laser speckle suppression device according to any one of claims 8-12, characterized in that, It further includes a second optical element. The first optical element is used to transmit a laser beam to perform a first suppression on the speckle of the laser beam. The second optical element is located in the optical path of the laser beam and is used to perform a second suppression on the speckle of the laser beam.

14. The laser speckle suppression device according to claim 13, wherein Both the first optical element and the second optical element are diffusion sheets. After the laser beam passes through the first optical element, a first suppression is performed on the speckle of the laser beam. The laser beam emitted from the first optical element passes through the second optical element and then exits, and the speckle of the laser beam is suppressed again.

15. The laser speckle suppression device according to claim 13, characterized in that, The first optical element is a diffusion sheet, and the second optical element is a mirror. After the laser beam passes through the first optical element, a first suppression is performed on the speckle of the laser beam. The laser beam emitted from the first optical element is reflected when it reaches the second optical element. The reflected laser beam passes through the first optical element again and then exits, and the speckle of the laser beam is suppressed again.

16. A laser speckle suppression device, characterized in that, It includes: A diffusion sheet for transmitting a laser beam; An elastic member provided on the outer peripheral side of the diffusion sheet, and the diffusion sheet and the elastic member form a spring oscillator. The elastic member includes a moving part, an elastic part, and a fixed part arranged in sequence from the inside to the outside. The moving part is connected to the diffusion sheet, one end of the elastic part is connected to the moving part, and the other end of the elastic part is connected to the fixed part; And A vibration source connected to the fixed part. The vibration source resonates with the spring oscillator in a preset mode, driving the diffusion sheet to vibrate along a preset direction to suppress the speckle of the laser beam.

17. The laser speckle suppression device according to claim 16, characterized in that, The elastic part is a planar spiral spring, a helical spring, or a flexible annular structural member.

18. The laser speckle suppression device according to claim 16, characterized in that, The elastic part includes N coils of springs arranged in the same plane, and N ≥ 2; The elastic member further includes a connection part. Adjacent coils of springs are connected by the connection part. The innermost coil of the spring is connected to the moving part by the connection part, and the outermost coil of the spring is connected to the fixed part by the connection part.

19. The laser speckle suppression device according to claim 18, characterized in that, Between the i-th coil of the spring and the (i + 1)-th coil of the spring, there are two connection parts symmetrically distributed along the first direction. Between the (i + 1)-th coil of the spring and the (i + 2)-th coil of the spring, there are two connection parts symmetrically distributed along the second direction. The first direction and the second direction are perpendicular to each other, where 1 ≤ i < N and i is odd.

20. The laser speckle suppression device according to claim 18, characterized in that, The gap d between adjacent coils of springs satisfies the following condition: 0.5 mm < d < 2 mm.

21. The laser speckle suppression device according to claim 16, characterized in that, The vibration source is disposed on the plane where the fixed part is located, and the vibration source is a linear vibration motor or a rotary motor.

22. The laser speckle suppression device according to any one of claims 16 to 21, characterized in that, The number of elastic elements is at least two, and the at least two elastic elements are spaced apart along a direction perpendicular to the diffuser sheet.

23. The laser speckle suppression device according to claim 22, characterized in that, A support assembly is provided between the elastic portions of two adjacent elastic elements.

24. The laser speckle suppression device according to claim 22, characterized in that, The distance between two adjacent elastic elements is 0.5mm to 1mm.

25. A laser projection device, characterized in that, include: A laser source, used to emit a laser beam; and The laser speckle suppression device as described in any one of claims 1-24 is disposed in the optical path of the laser beam.

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