Low-cost high-brightness color light projection system

Abstract

The utility model relates to a low-cost high-brightness color light projection system, which comprises a laser emission module, a polarization splitting prism, a quarter-wave plate and a micro electro mechanical system (MEMS) which are arranged along the direction of a first light path, multicolor laser emitted by the laser emission module is combined and collimated into combined light, and the combined light sequentially passes through the polarization splitting prism and the quarter-wave plate and then enters the MEMS. And the MEMS comprises a rotatable light reflection part which is used for reflecting the combined light beam to an imaging area along a second light path to form a projection image. According to the utility model, the overall structure is simple, and the combined light after beam combination and collimation can effectively utilize a smaller reflecting surface on the MEMS, thereby ensuring that the output image has high brightness; by optimizing the light path structure, another light path output of reflected light (output light) is realized by using the polarization splitting prism and the quarter-wave plate, so that the size can be reduced, and the cost can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of optics, in particular to a low-cost and high-brightness color light projection system. Background Art

[0002] Laser MEMS scanning projection technology is a new display technology that has developed rapidly in recent years in fields such as AR smart glasses, mobile phone projection, smart wearables, and smart office. In the application of laser MEMS scanning projection technology, multiple lasers are required, and the light beams generated by multiple lasers also need to be combined to produce a vivid display image. However, in the prior art, the structure and optical path of the laser projection system are complex, the cost is high, and the popularity rate is low. Content of the Utility Model

[0003] In order to solve the above problems of the prior art, the utility model provides a low-cost and high-brightness color light projection system.

[0004] In order to achieve the above purpose, the main technical solutions adopted by the utility model include:

[0005] A low-cost and high-brightness color light projection system includes a laser emission module, a polarization beam splitter prism, a quarter-wave plate, and a microelectromechanical system MEMS arranged along the first optical path direction; the multi-color laser emitted by the laser emission module is combined and collimated into a combined beam of light, and then sequentially passes through the polarization beam splitter prism and the quarter-wave plate and enters the microelectromechanical system MEMS; the microelectromechanical system MEMS includes a rotatable light reflection part for reflecting the combined beam of light along the second optical path to an imaging area to form a projection image.

[0006] Further, the laser emission module includes three laser sources that respectively emit three laser beams with different wavelengths; the three laser beams with different wavelengths are respectively a first primary color light, a second primary color light, and a third primary color light; the first primary color light, the second primary color light, and the third primary color light respectively correspond to one of red light, green light, and blue light and do not repeat each other.

[0007] Further, the multi-color laser emitted by the laser emission module is a linearly polarized light with a P polarization angle after being combined; the combined beam of light after passing through the polarization beam splitter prism and the quarter-wave plate enters the microelectromechanical system MEMS in a circularly polarized state; the laser beam after the microelectromechanical system MEMS reflects the combined beam of light and passes through the quarter-wave plate is a linearly polarized light with an S polarization angle; the linearly polarized light with an S polarization angle forms a projection image along the second optical path to the imaging area.

[0008] Further, the transmission opening angle of the rotatable light reflection part of the microelectromechanical system MEMS is adjustable.

[0009] Further, the microelectromechanical system (MEMS) is an electrostatic MEMS, and includes a drive voltage adjustment unit for adjusting the projection angle of the rotatable light reflection part.

[0010] Further, the microelectromechanical system (MEMS) is an electromagnetic MEMS, and includes a drive current adjustment unit for adjusting the projection angle of the rotatable light reflection part.

[0011] Further, the laser emission module includes a plurality of lasers and a beam combining prism; the beam combining prism includes at least three partially reflective surfaces arranged in parallel; the number of lasers is equal to and corresponds one-to-one with the number of partially reflective surfaces; the emitted light of the lasers is collimated and output through a collimating lens arranged at the light output port of the beam combining prism after being reflected and combined by the partially reflective surfaces;

[0012] Further, the beam combining prism includes a beam combining reflective surface parallel to the partially reflective surfaces; the emitted light of the lasers is collimated and output through a collimating lens arranged at the light output port of the beam combining prism after being reflected and combined by the partially reflective surfaces and then being reflected by the beam combining reflective surface; the beam combining prism includes three partially reflective surfaces, which are the first partially reflective surface, the second partially reflective surface, and the third partially reflective surface from bottom to top; the lasers include a first laser opposite to the first partially reflective surface, a second laser opposite to the second partially reflective surface, and a third laser opposite to the third partially reflective surface; the first partially reflective surface can reflect the first wavelength light emitted by the first laser; the second partially reflective surface can reflect the second wavelength light emitted by the second laser and transmit the first wavelength light; the third partially reflective surface can reflect the third wavelength light emitted by the third laser and transmit the first wavelength light and the second wavelength light; the beam combining reflective surface can reflect the first wavelength light, the second wavelength light, and the third wavelength light.

[0013] Further, the angle between the partially reflective surface and the horizontal plane is 45°, and the emitted light of the lasers is horizontally emitted; the beam combining prism is a cylindrical lens with an integral structure; the cylindrical lens is composed of at least three prisms spliced in sequence from bottom to top; partial reflection films or dichroic mirrors are provided at the splicing joints of the prisms and at the lowermost end of the integral cylindrical lens structure formed to form partially reflective surfaces, and a total reflection film is provided at the uppermost end of the integral cylindrical lens structure to form a beam combining reflective surface; a support lens is provided at the bottom of the beam combining prism so that the lower bottom surface of the beam combining lens is flush with the horizontal plane.

[0014] The beneficial effects of the present utility model are as follows: 1. The scanning core uses MEMS, and realizes the full-range change of θx and θy at different voltage values, so as to realize the continuous scanning of the scanning beam in a two-dimensional plane;

[0015] 2. After multi-beam combination, at the vertical incident angle (or within a small angle range), make full use of the effective reflection area of the MEMS.

[0016] 3. For any point, colored light is obtained from the intensity combination of multi-wavelength signals.

[0017] 4. The incident light on the polarization beam splitter prism is linearly polarized light at the P polarization angle. Then, after passing through a quarter-wave plate, it is incident on the reflection surface of the MEMS in the state of circularly polarized light. After deflection and reflection, and then passing through a quarter-wave plate again, it becomes linearly polarized light that turns 90°. It is reflected on the polarization beam splitter prism and output along the second optical path, forming a colored projection image in the imaging area. The overall structure is simple. The combined beam after beam combination and collimation can effectively utilize the small reflection surface on the MEMS, thus ensuring that the output image has high brightness. By optimizing the optical path structure, the polarization beam splitter prism and the quarter-wave plate are used to realize the output of the reflected light (output light) in another optical path, which can not only reduce the volume but also lower the cost.

[0018] 5. An integrated beam-combining prism is used to couple the beams, replacing the structure with several traditional lens groups, greatly reducing the volume of the module and the difficulty of alignment and adjustment; improving the multi-wavelength fiber coupling efficiency and consistency; the smaller space volume and compactness are beneficial to the structural stability and heat dissipation performance of the module; at the same time, it is convenient for large-scale automated production; through reasonable optical path design, an integrated optical path structure is formed by the beam-combining prism, greatly reducing the tolerances caused by the coupling process and the time required for coupling, improving the optical path stability, and being able to achieve the purpose of simultaneously coupling multiple laser beams into a single optical fiber under a certain coupling efficiency; the integrated beam-combining prism is designed as a cylindrical lens, which can reduce the spot size of the output light and is easier to couple into the optical fiber; the support lens ensures that the beam-combining prism has a flat bottom surface and is easier to install when it is fixed. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic structural diagram of the present invention;

[0021] Figure 2 It is a schematic optical path diagram of an embodiment of the laser emission module of the present invention;

[0022] Figure 3 It is a schematic structural diagram of the beam-combining prism of an embodiment of the present invention;

[0023] Description of the reference numerals: 10, laser emission module; 20, polarization beam splitter prism; 30, quarter-wave plate; 40, microelectromechanical system MEMS; 50, projection image; 100, beam combining prism; 110, partial reflection surface; 111, first partial reflection surface; 112, second partial reflection surface; 113, third partial reflection surface; 120, beam combining reflection surface; 130, support lens; 200, laser; 210, first laser; 211, light of the first wavelength; 220, second laser; 221, light of the second wavelength; 230, third laser; 231, light of the third wavelength; 300, collimating lens. Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some but not all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without any creative efforts shall fall within the protection scope of the present utility model. Therefore, the detailed description of the embodiments of the present utility model provided in the accompanying drawings is not intended to limit the scope of the present utility model to be protected, but merely represents the selected embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without any creative efforts shall fall within the protection scope of the present utility model.

[0025] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0026] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, terms such as "installation", "provided with", "connection", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0027] A low-cost and high-brightness color light projection system includes a laser emission module 10, a polarization beam splitter prism 20, a quarter-wave plate 30, and a micro-electro-mechanical system MEMS 40 arranged along the first optical path direction; the multi-color laser emitted by the laser emission module 10 is combined and collimated into a combined beam of light, and then passes through the polarization beam splitter prism 20 and the quarter-wave plate 30 in sequence and enters the micro-electro-mechanical system MEMS 40 (Micro-Electro-Mechanical System); the micro-electro-mechanical system MEMS 40 includes a rotatable light reflection part for reflecting the combined beam of light along the second optical path to the imaging area to form a projection image 50; there are tiny reflection mirrors inside the MEMS, and the reflection mirror surface can perform two-dimensional rotation under the control of a drive circuit; different voltages can obtain different scanning angles (rotation angles), and a pattern composed of colored light points can be obtained within the scanning range; in one embodiment, the transmission opening angle of the rotatable light reflection part of the micro-electro-mechanical system MEMS 40 is adjustable; in one embodiment, the micro-electro-mechanical system MEMS 40 is an electrostatic MEMS, including a drive voltage adjustment unit for adjusting the projection opening angle of the rotatable light reflection part; in one embodiment, the micro-electro-mechanical system MEMS 40 is an electromagnetic MEMS, including a drive current adjustment unit for adjusting the projection opening angle of the rotatable light reflection part.

[0028] In one embodiment, the laser emission module 10 includes three laser sources that respectively emit three laser beams with different wavelengths; the three laser beams with different wavelengths are respectively a first primary color light, a second primary color light, and a third primary color light; the first primary color light, the second primary color light, and the third primary color light are respectively red light, green light, and blue light; in another embodiment, the first primary color light, the second primary color light, and the third primary color light are respectively red light, blue light, and green light; that is, the first primary color light, the second primary color light, and the third primary color light only need to respectively correspond to one of the three-color lasers of red light, green light, and blue light and do not repeat each other.

[0029] In another embodiment, the laser emission module 10 includes a laser driver and a laser light source assembly, and the laser driver drives the laser light source assembly to emit laser light.

[0030] In one embodiment, the multi-color laser emitted by the laser emission module 10 is a linearly polarized light with a P polarization angle after beam combination; the combined light enters the microelectromechanical system MEMS 40 in a circularly polarized state after passing through the polarization beam splitter prism 20 and the quarter-wave plate 30; the laser light that passes through the quarter-wave plate 30 after being reflected by the microelectromechanical system MEMS 40 is a linearly polarized light with an S polarization angle; the linearly polarized light with an S polarization angle forms a projection image 50 in the imaging area along the second optical path; the second optical path specifically refers to the path from the microelectromechanical system 40 MEMS - quarter-wave plate - polarization beam splitter prism 20 - projection image 50;

[0031] In one embodiment, the laser emission module includes a plurality of lasers 200 and a beam combination prism 100; preferably, there are three lasers 200, and the beam combination prism 100 includes at least three partially reflecting surfaces 110 arranged in parallel and a beam combination reflecting surface 120 arranged in parallel with the partially reflecting surfaces 110; the number of the lasers 200 is equal to and corresponds to the number of the partially reflecting surfaces 110 one by one; the emitted light of the lasers 200 is reflected by the partially reflecting surfaces 110 and then reflected by the beam combination reflecting surface 120 and output.

[0032] As Figure 2-3As shown in the figure; the beam combining prism 100 includes three partial reflection surfaces 110, which are the first partial reflection surface 111, the second partial reflection surface 112, and the third partial reflection surface 113 from bottom to top; the laser 200 includes a first laser 210 disposed opposite to the first partial reflection surface 111, a second laser 220 disposed opposite to the second partial reflection surface 112, and a third laser 230 disposed opposite to the third partial reflection surface 113; the first partial reflection surface 111 can reflect the first wavelength light 211 emitted by the first laser 210; the second partial reflection surface 112 can reflect the second wavelength light 221 emitted by the second laser 220 and transmit the first wavelength light 211; the third partial reflection surface 113 can reflect the third wavelength light 231 emitted by the third laser 230 and transmit the first wavelength light 211 and the second wavelength light 221; the beam combining reflection surface 120 can reflect the first wavelength light 211, the second wavelength light 221, and the third wavelength light 231; the angle between the partial reflection surface 110 and the horizontal plane is 45°, and the emitted light of the laser 200 is horizontally emitted; the beam combining prism 100 is a cylindrical lens with an integral structure; the cylindrical lens is formed by splicing three prisms in sequence from bottom to top; partial reflection films or dichroic mirrors are provided at the splicing joints of the prisms and at the lowermost end of the integral cylindrical lens to form the partial reflection surface 110; a total reflection film or a mirror is provided at the uppermost end of the integral cylindrical lens to form the beam combining reflection surface 120; when the partial reflection surface 110 is composed of dichroic mirrors, the dichroic mirrors are glued to the prisms, and UV glue is used for gluing; the first wavelength light 211, the second wavelength light 221, and the third wavelength light 231 are combined and collimated to form combined light, which successively passes through a polarization beam splitter prism 20 and a quarter-wave plate 30 and then enters a microelectromechanical system MEMS 40;

[0033] In one embodiment, the beam combining reflection surface 120 may not be provided, and the light is directly output after being combined by the partial reflection surface 110. In this embodiment, the incident end and the output end of the laser are not on the same side;

[0034] The beam combining prism 100 is set as an integral structure, which can realize large-scale automated production, and at the same time replace the structure of several traditional lens groups, reduce the volume while reducing the assembly and adjustment difficulty, ensure the multi-wavelength fiber coupling efficiency and consistency, and the small volume is also beneficial to structural stability and uniform heat dissipation; the partial reflection surface 110 can also filter out stray light of other wavelengths; the integral cylindrical lens can reduce the spot of the finally emitted light and reduce the coupling difficulty; a collimating lens 300 is provided at the light output port of the beam combining prism 100 to achieve collimated output and improve the light output quality;

[0035] In one embodiment, since the cylindrical lens is formed by splicing three prisms in sequence from bottom to top, a partial reflection film or a dichroic mirror needs to be provided at the lowermost end of the integral cylindrical lens. Since the angle between the partial reflection surface 110 and the horizontal plane is 45°, the lowermost end of the integral cylindrical lens also forms an angle of 45° with the horizontal plane, resulting in a non-flat structure at the bottom of the beam combining prism 100, which increases the assembly difficulty to a certain extent. Therefore, a support lens 130 is provided at the bottom of the beam combining prism 100 to make the lower bottom surface of the beam combining lens flush with the horizontal plane, thereby reducing the assembly difficulty. Similarly, a top lens can be provided at the top of the beam combining reflection surface 120 to make its top flush with the horizontal plane, which is beneficial to assembly.

[0036] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in the related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A low-cost and high-brightness color light projection system, characterized in that: It includes a laser emission module (10), a polarization beam splitter prism (20), a quarter-wave plate (30), and a microelectromechanical system MEMS (40) arranged along the first optical path direction; the multi-color laser emitted by the laser emission module (10) is combined and collimated into a combined beam of light, and then successively passes through the polarization beam splitter prism (20) and the quarter-wave plate (30) and then enters the microelectromechanical system MEMS (40); the microelectromechanical system MEMS (40) includes a rotatable light reflection part for reflecting the combined beam of light along the second optical path to the imaging area to form a projection image (50).

2. The low-cost and high-brightness color light projection system according to claim 1, wherein: The laser emission module (10) includes three laser sources that respectively emit three laser beams with different wavelengths; the three laser beams with different wavelengths are respectively a first primary color light, a second primary color light, and a third primary color light; the first primary color light, the second primary color light, and the third primary color light respectively correspond to one of red light, green light, and blue light and do not repeat each other.

3. A low-cost and high-brightness color light projection system according to claim 1, characterized in that: The multi-color laser emitted by the laser emission module (10) is a linearly polarized light with a P polarization angle after being combined; the combined beam of light after passing through the polarization beam splitter prism (20) and the quarter-wave plate (30) enters the microelectromechanical system MEMS (40) in a circularly polarized state.

4. A low-cost and high-brightness color light projection system according to claim 3, characterized in that: The laser beam that passes through the quarter-wave plate (30) after the microelectromechanical system MEMS (40) reflects the combined beam of light is a linearly polarized light with an S polarization angle; the linearly polarized light with an S polarization angle forms a projection image (50) along the second optical path to the imaging area.

5. A low-cost and high-brightness color light projection system according to claim 1, characterized in that: The transmission opening angle of the rotatable light reflection part of the microelectromechanical system MEMS (40) is adjustable.

6. The low-cost and high-brightness color light projection system according to claim 1, wherein: The microelectromechanical system MEMS (40) is an electrostatic MEMS and includes a drive voltage adjustment unit for adjusting the projection opening angle of the rotatable light reflection part.

7. A low-cost and high-brightness color light projection system according to claim 1, characterized in that: The microelectromechanical system MEMS (40) is an electromagnetic MEMS and includes a drive current adjustment unit for adjusting the projection opening angle of the rotatable light reflection part.

8. A low-cost and high-brightness color light projection system according to claim 1, characterized in that: The laser emission module (10) includes a plurality of lasers (200) and a beam combining prism (100); the beam combining prism (100) includes at least three partially reflecting surfaces (110) arranged in parallel; the number of lasers (200) is equal to the number of partially reflecting surfaces (110) and they correspond one by one; the outgoing light of the lasers (200) is combined by reflection through the partially reflecting surfaces (110) and then collimated and output through a collimating lens (300) arranged at the light output port of the beam combining prism (100).

9. A low-cost high-brightness color light projection system according to claim 8, characterized in that: The beam combining prism (100) includes a beam combining reflecting surface (120) parallel to the partially reflecting surface (110); the outgoing light of the lasers (200) is combined by reflection through the partially reflecting surfaces (110) and then reflected through the beam combining reflecting surface (120) and then collimated and output through a collimating lens (300) arranged at the light output port of the beam combining prism (100). The combined beam prism (100) includes three partial reflection surfaces (110), which are the first partial reflection surface (111), the second partial reflection surface (112), and the third partial reflection surface (113) from bottom to top; the laser (200) includes a first laser (210) arranged opposite to the first partial reflection surface (111), a second laser (220) arranged opposite to the second partial reflection surface (112), and a third laser (230) arranged opposite to the third partial reflection surface (113); the first partial reflection surface (111) can reflect the first wavelength light (211) emitted by the first laser (210); the second partial reflection surface (112) can reflect the second wavelength light (221) emitted by the second laser (220) and transmit the first wavelength light (211); the third partial reflection surface (113) can reflect the third wavelength light (231) emitted by the third laser (230) and transmit the first wavelength light (211) and the second wavelength light (221); the combined beam reflection surface (120) can reflect the first wavelength light (211), the second wavelength light (221), and the third wavelength light (231).

10. A low-cost and high-brightness color light projection system according to claim 8, characterized in that: The angle between the partial reflection surface (110) and the horizontal plane is 45°, and the emitted light of the laser (200) is horizontally emitted; the combined beam prism (100) is a cylindrical lens with an integral structure; the cylindrical lens is composed of at least three prisms spliced in sequence from bottom to top; partial reflection films or dichroic mirrors are provided at the splicing joints of the prisms and at the lowermost end of the integral cylindrical lens structure formed to form the partial reflection surface (110), and a total reflection film is provided at the uppermost end of the integral cylindrical lens structure to form the combined beam reflection surface (120); a support lens (130) is provided at the bottom of the combined beam prism (100) to make the lower bottom surface of the combined beam lens flush with the horizontal plane.

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