Representation method

Abstract

To provide an optical engine module and a projection device.SOLUTION: An optical engine module includes a light source unit, a first diffusion element, a polarizing beam splitting element, a second diffusion element, and a light valve. The light source unit emits a light beam. The first diffusion element is located on a transmission path of the light beam. The polarizing beam splitting element is located on the transmission path of the light beam. The first diffusion element is located between the polarizing beam splitting element and the light source unit. The second diffusion element has at least one optical surface to reflect and diffuse the light beam. The light beam forms an illumination beam after passing through the second diffusion element, and the illumination beam has an optical image matching angle. The light valve is located on the transmission path of the illumination beam. The light valve converts the illumination beam to an image beam. While the present invention maintains the optical image matching angle of the illumination beam, the present invention can reduce a divergence angle of a plurality of sub-beams of the beam before entering the polarizing beam splitting element.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to an optical module and an optical device, and more particularly to an optical engine module and a projection device. [Background technology]

[0002] With advances in display technology and people's expectations for high technology, near-eye displays (NEDs) and head-mounted displays (HMDs) are currently considered to have great potential for development. Applications of near-eye display technology can currently be divided into augmented reality (AR) and virtual reality (VR). Light field near-eye displays (LFNEDs) possess real-time light field information, enabling a post-focus effect and providing depth-based image information, making them widely used in augmented reality and virtual reality near-eye display technologies.

[0003] Generally speaking, in an optical engine module for near-eye display technology, optical path designs using optical elements such as a polarizing beam splitter, a microlens array, and a focusing lens are used to ensure that the image light beam entering the imaging system is aligned with the pupil of the imaging system. However, due to the beam splitting characteristics of the polarizing beam splitter, light beams of different frequency bands incident at large angles have different transmittances, which makes it easy for color cast to occur for light beams incident at large angles. Therefore, when an imaging system requires a field angle greater than a certain angle, the light collection efficiency of the polarizing beam splitter at large angles may decrease or off-axis color unevenness may occur, further affecting the imaging quality.

[0004] The "Background Art" section is intended to facilitate understanding of the present invention, and the content disclosed in the "Background Art" may include some configurations other than the prior art known to those skilled in the art. The content disclosed in the "Background Art" does not imply that the content or the problems that one or more embodiments of the present invention are intended to solve were already understood or recognized by those skilled in the art prior to the filing of the present invention. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides an optical engine module with good image quality and resolution.

[0006] The present invention provides a projection device with good image quality and resolution. [Means for solving the problem]

[0007] Other objects and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

[0008] To achieve one, some, or all of the above objects, or other objects, one embodiment of the present invention provides an optical engine module. The optical engine module includes a light source unit, a first diffusing element, a polarizing beam splitting element, a second diffusing element, and a light valve. The light source unit emits a light beam. The first diffusing element is located on a transmission path of the light beam. The polarizing beam splitting element is located on the transmission path of the light beam, and the first diffusing element is located between the polarizing beam splitting element and the light source unit. The second diffusing element has at least one optical surface that reflects and diffuses the light beam, and the light beam forms an illumination light beam after passing through the second diffusing element, and the illumination light beam has an optical imaging matching angle. The light valve is located on the transmission path of the illumination light beam, and the light valve modulates the illumination light beam into an image light beam.

[0009] To achieve one, some, or all of the above objects, or other objects, one embodiment of the present invention provides a projection device, including the optical engine module and a projection lens assembly, the projection lens assembly being located on a transmission path of an image beam and projecting the image beam from the projection device.

[0010] As described above, the embodiments of the present invention have at least one of the following advantages or effects. In the embodiments of the present invention, the projection apparatus and the optical engine module are configured with a first diffusing element and a second diffusing element to continuously increase the unit light divergence angle of the plurality of sub-beams of the light beam, thereby forming a plurality of sub-illumination beams that meet the needs of the optical path in the projection lens assembly. This allows the projection apparatus to use the illumination beam formed by the optical engine module to meet the needs of the optical path in the projection lens assembly, thereby achieving good image quality and resolution. Therefore, while maintaining the light imaging matching angle of the illumination beam, the divergence angle of the plurality of sub-beams of the light beam on the polarizing optical surface facing the first surface can be reduced. This allows the characteristics of the coating on the polarizing optical surface facing the first surface of the polarizing beam splitting element to be designed to be suitable for a light beam with a relatively small light divergence angle, thereby further reducing product costs and maintaining imaging quality.

[0011] In order to more clearly and understandably show the above features and advantages of the present invention, the following detailed description will be given with reference to the accompanying drawings and examples. [Brief explanation of the drawings]

[0012] [Figure 1A] 1 is a schematic diagram of the optical configuration of a projection apparatus according to an embodiment of the present invention. [Figure 1B] Structural schematic of the microstructure in Figure 1A. [Figure 2] FIG. 10 is a schematic diagram of the optical configuration of another projection device according to an embodiment of the present invention. [Figure 3] FIG. 10 is a schematic diagram of the optical configuration of yet another projection device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The above and other technical contents, features, and advantages of the present invention will be more clearly shown in the following detailed description of preferred embodiments with reference to the drawings. Directional terms used in the following embodiments, such as up, down, left, right, front, and rear, are only directions referring to the drawings. Therefore, the directional terms used are for the purpose of explanation only and do not limit the present invention.

[0014] FIG. 1A is a schematic diagram of the optical configuration of a projection device according to an embodiment of the present invention. FIG. 1B is a structural schematic diagram of the microstructure of FIG. 1A. Referring to FIGS. 1A and 1B, in this embodiment, the projection device 200 is, for example, a near-eye display device, positioned in front of at least one eye of a user. Specifically, as shown in FIG. 1A, the projection device 200 includes an optical engine module 100 and a projection lens assembly 210. Specifically, the optical engine module 100 includes a light source unit 110, a first diffusing element 120, a polarizing beam splitting element 130, a second diffusing element 140, and a light valve 150. Although the number of projection lens assemblies 210 is shown as multiple, this is merely an example of the projection device including multiple imaging lenses. However, the present invention is not limited thereto, and the number of projection lens assemblies 210 may be one. In this embodiment, the light source unit 110 includes a laser diode (LD) to provide a light beam 60, i.e., the light beam 60 is a laser beam. The laser light emitting elements may be, for example, blue, red, and green light sources, but the present invention is not limited thereto. The light source unit 110 further includes a dichroic mirror that transmits or reflects the colored light emitted from the blue, red, and green light sources.

[0015] In this embodiment, the light valve 150 is, for example, a reflective light valve, and can modulate the illumination light beam 70 into the image light beam 80 .

[0016] 1A , in this embodiment, the first diffusing element 120, the polarizing beam splitting element 130, and the second diffusing element 140 are located on the transmission path of the light beam 60. The first diffusing element 120 is located between the polarizing beam splitting element 130 and the light source unit 110 and diffuses the light beam 60. The second diffusing element 140 has at least one optical surface and reflects and diffuses the light beam 60. For example, the first diffusing element 120 includes a first microlens array 121, and the second diffusing element 140 includes a second microlens array 141 and an optical reflecting mirror 142. In this embodiment, the at least one optical surface includes the surface of the second microlens array 141 and the surface of the optical reflecting mirror 142. The second microlens array 141 of the second diffusion element 140 is located between the optical reflection mirror 142 and the polarizing beam splitting element 130, and the reflection surface of the optical reflection mirror 142 faces away from the polarizing beam splitting element 130.

[0017] In this embodiment, the polarizing beam splitting element 130 has a first surface S1, a second surface S2, a third surface S3, a fourth surface S4, and a polarizing optical surface PBS, where the first surface S1 and the second surface S2 are opposite each other, the third surface S3 and the fourth surface S4 are opposite each other, and the third surface S3 and the fourth surface S4 are connected to the first surface S1 and the second surface S2. As shown in FIG. 1A , a light beam 60 passes through the first diffusing element 120 and enters the polarizing beam splitting element 130 from the first surface S1. The light beam 60 then leaves the polarizing beam splitting element 130 from the second surface S2 and is transmitted to the second diffusing element 140. The light beam 60 then passes through the second microlens array 141 of the second diffusing element 140, whereby the sub-light beams of the light beam 60 are diffused twice by a unit light divergence angle. Then, the light beam 60 passes through the optical reflecting mirror 142 of the second diffusing element 140 and is reflected back to the polarizing beam splitting element 130. In addition, the optical engine module 100 further includes a quarter-wave plate 160 located between the second diffusing element 140 and the polarizing beam splitting element 130. Therefore, after the sub-light beams of the light beam 60 are reflected back to the polarizing beam splitting element 130, their polarization states are changed, and they are reflected by the polarizing optical surface PBS facing the polarizing beam splitting element 130, pass through the third surface S3, and then transmitted to the light valve 150.

[0018] 1A , in this embodiment, after the light valve 150 modulates the illumination light beam 70 into an image light beam 80 having a plurality of sub-image light beams, the image light beam 80 passes through the third surface S3, the polarizing optical surface PBS, and the fourth surface S4 of the polarizing beam splitting element 130 in order, before leaving the polarizing beam splitting element 130 and being transmitted to the pupil PL. For example, in this embodiment, the pupil PL may be the exit pupil of the projection lens assembly 210 or the pupil of a user's eye. When the pupil PL is the pupil of a user's eye, the projection device 200 can be applied to virtual reality (VR) technology.

[0019] Generally speaking, the entire optical shape of the illumination light beam 70 needs to satisfy a specific emission angle range so that the illumination light beam 70 formed after the light beam 60 leaves the optical engine module 100 can satisfy the required visual angle range for the optical path in the projection lens assembly 210, and so that each sub-image light beam that passes through the projection lens assembly 210 can provide the divergence angle range that must be satisfied when transmitted to the pupil PL, i.e., the optical imaging matching angle of the illumination light beam 70 matches the visual angle of the pupil PL.

[0020] Furthermore, in this embodiment, the first diffusing element 120 and the second diffusing element 140 can adjust the uniformity and light shape of the plurality of sub-beams of the light beam 60, so that after at least one light beam 60 passes through the first diffusing element 120 and the second diffusing element 140, the sub-beam has a large etendue and a uniform light shape. In this way, the plurality of sub-beams of the at least one light beam 60 pass through the first diffusing element 120 and the second diffusing element 140 to form the illumination light beam 70 with a light imaging matching angle.

[0021] 1B, for example, the first microlens array 121 has a plurality of microstructures MS, or the second microlens array 141 has a plurality of microstructures MS. The plurality of microstructures MS correspond to the plurality of sub-beams, thereby diverging the unit light divergence angles of the plurality of sub-beams and forming a plurality of sub-illumination beams of the illumination beam 70. In this embodiment, the average width of the plurality of microstructures MS is 150 micrometers (μm), but the present invention is not limited thereto and may be set to 100 micrometers (μm) or other values.

[0022] In addition, the first diffusion element 120 and the second diffusion element 140 may include a microlens array, or may include one of a surface scattering type diffusion sheet, a volume scattering type diffusion sheet, and a diffraction element, which diffuses the unit light divergence angle of the sub-beams of the light beam 60 and forms multiple sub-illumination beams of the illumination light beam 70.

[0023] For example, the first diffusing element 120 and the second diffusing element 140 may employ a first diffusing sheet and a second diffusing sheet, which are surface-scattering diffusing sheets, instead of the first microlens array 121 and the second microlens array 141. The surfaces of the first diffusing sheet and the second diffusing sheet have a plurality of uneven structures, which can diffuse the unit light divergence angles of the plurality of sub-beams and achieve the same function as the microstructure MS of the first microlens array 121 and the second microlens array 141 shown in FIG. 1B, but the description thereof will be omitted here.

[0024] In this way, after the plurality of sub-beams of the light beam 60 pass through the first diffusing element 120 and the second diffusing element 140, the unit light divergence angles of the plurality of sub-beams of the light beam 60 are continuously expanded, thereby forming a plurality of illumination sub-beams that meet the needs of the optical path in the projection lens assembly 210. Furthermore, since the plurality of sub-beams of the light beam 60 undergoes light shape adjustment by passing through the first diffusing element 120 and the second diffusing element 140 back and forth, the divergence angles can be adjusted in stages. The first diffusing element 120 first performs primary light diffusion on the plurality of sub-beams of the light beam 60, and then the second diffusing element 140 performs secondary light diffusion on the plurality of sub-beams of the light beam 60 that have passed back and forth. In this way, the divergence angles of the plurality of sub-beams of the light beam 60 at the polarizing optical surface PBS facing the first surface S1 can be reduced while maintaining the optical imaging matching angle of the illumination light beam 70. This allows the characteristics of the coating film on the polarizing optical surface PBS facing the first surface S1 of the polarizing beam splitting element 130 to be designed to be suitable for the light beam 60 having a relatively small light diffusion angle, thereby further reducing product costs and maintaining imaging quality.

[0025] In this way, the illumination light beam 70 formed after the at least one light beam 60 passes through the first diffusing element 120 has an optical imaging matching angle, and the multiple sub-illumination light beams providing each sub-image light ray in the illumination light beam 70 also have a relatively large field angle, which can meet the needs of the optical path in the projection lens assembly 210 and further meet the divergence angle range required by the pupil PL. As a result, the projection apparatus 200 can use the illumination light beam 70 formed by the optical engine module 100 to meet the needs of the optical path in the projection lens assembly 210, thereby achieving good image quality and resolution.

[0026] 2 is a schematic diagram of the optical configuration of another projection device according to an embodiment of the present invention. Referring to FIG. 2, the projection device 200A of the embodiment of FIG. 2 is similar to the projection device 200 of FIG. 1A, but differs in the following respects: In this embodiment, the second diffusing element 140A of the projection device 200A includes a microstructured optical sheet 141A, which has a first optical surface OS1 and a second optical surface OS2, and at least one optical surface of the second diffusing element 140A includes the first optical surface OS1 and the second optical surface OS2 of the second microlens array 141, where the first optical surface OS1 is located between the polarizing beam splitting element 130 and the second optical surface OS2, the first optical surface OS1 is a surface on which a plurality of microlens elements ML are formed, and the second optical surface OS2 is a reflective surface. In this embodiment, the second optical surface OS2 may be a flat surface. When the second optical surface OS2 is a flat surface, the second diffusing element 140A further includes an optical lens LE, which is located between the microstructured optical sheet 141A and the polarizing beam splitting element 130. In this embodiment, the microlens element ML located on the first optical surface OS1 can also diffuse the unit light divergence angle of the multiple sub-beams and achieve the same function as the microstructure MS shown in FIG. 1B, but its description is omitted here. In another embodiment, the first optical surface OS1 is a surface of a micro-reflection mirror array, and the beams are reflected immediately upon reaching the first optical surface OS1. In this embodiment, the second optical surface OS2 may be omitted.

[0027] In this way, by arranging the first diffusing element 120 and the second diffusing element 140A, the projection device 200A can continuously expand the unit light divergence angle of multiple sub-beams of the light beam 60 to form multiple sub-illumination beams that can meet the needs of the optical path in the projection lens assembly 210, and can further achieve similar effects and advantages to the projection device 200, but the description thereof will be omitted here.

[0028] FIG. 3 is a schematic diagram of the optical configuration of yet another projection device according to an embodiment of the present invention. Referring to FIG. 3, the second diffusing element 140B of the projection device 200B of the embodiment of FIG. 3 is similar to the second diffusing element 140A of the projection device 200A of FIG. 2, but differs in the following respects: The second diffusing element 140B includes a microstructured optical sheet 141B, and the second optical surface OS2 of the microstructured optical sheet 141B is curved. The second diffusing element 140B also has a plurality of microstructures for diffusing the light beam 60. The microstructures may be located on the second optical surface OS2 or the first optical surface OS1 of the microstructured optical sheet 141B, but in this embodiment, the first optical surface OS1 is flat. In this embodiment, the microstructures of the second diffusing element 140B can also diffuse the unit light divergence angle of multiple sub-beams and achieve the same function as the microstructure MS shown in FIG. 1B, but their description will be omitted here.

[0029] In this way, by disposing the first diffusing element 120 and the second diffusing element 140B, the projection device 200B can continuously expand the unit light divergence angle of the multiple sub-beams of the light beam 60 to form multiple sub-illumination beams that can meet the needs of the optical path in the projection lens assembly 210, and can further achieve effects and advantages similar to those of the projection device 200A, but the description thereof will be omitted here.

[0030] In summary, embodiments of the present invention have at least one of the following advantages or effects: In embodiments of the present invention, the projection apparatus and the optical engine module are configured with a first diffusing element and a second diffusing element to continuously expand the unit light divergence angle of the plurality of sub-beams of a light beam to form a plurality of sub-illumination beams that meet the needs of the optical path in the projection lens assembly. This allows the projection apparatus to use the illumination beam formed by the optical engine module to meet the needs of the optical path in the projection lens assembly, thereby achieving good image quality and resolution. Therefore, while maintaining the light imaging matching angle of the illumination beam, the divergence angle of the plurality of sub-beams of the light beam on the polarizing optical surface facing the first surface can be reduced. This allows the characteristics of the coating on the polarizing optical surface facing the first surface of the polarizing beam splitting element to be designed to be suitable for a light beam with a relatively small light divergence angle, thereby further reducing product costs and maintaining imaging quality.

[0031] The above are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. In other words, all simple and equivalent modifications and alterations based on the claims and the content of the present invention fall within the scope of the present invention. Furthermore, any embodiment or claim of the present invention does not necessarily have all of the objectives, advantages, or features disclosed in the present invention. Furthermore, the abstract and title of the invention are for use in patent document searches and do not limit the scope of the present invention. Furthermore, terms such as "first," "second," etc., used in the specification or claims indicate the names of elements or distinguish between different embodiments or scopes, and do not limit the number of elements. [Explanation of symbols]

[0032] 60 luminous flux 70 luminous flux 80 image luminous flux 100 Optical Engine Module 110 Light source unit 120 first diffusion element 121 First microlens array 130 Polarizing Beam Splitting Element 140, 140A, 140B Second diffusion element 141 Second microlens array 141A, 141B Microstructured Optical Sheet 142 Optical Reflecting Mirror 150 Light Bulb 160 Quarter Wave Plate 200, 200A, 200B projection device 210 Projection Lens Assembly LE Optical Lens ML Microlens Element MS microstructure OS optical surface OS1 1st optical surface OS2 2nd optical surface PL Hitomi PBS polarized optical surface S1 1st surface S2 2nd surface S3 3rd surface S4 4th surface.

Claims

1. 1. An optical engine module, comprising: a light source unit including a laser light emitting element and emitting a laser beam; a first diffusion element located on a transmission path of the laser beam; a polarizing beam splitting element located on a transmission path of the laser beam; a second diffusing element having at least one optical surface; a light valve; the first diffusion element is located between the polarizing beam splitting element and the light source unit, and no other element is disposed between the first diffusion element and the polarizing beam splitting element; the at least one optical surface reflects and diffuses the laser beam from the polarizing beam splitting element, and the laser beam is transmitted to the first diffusing element and the second diffusing element in sequence, so that the laser beam forms an illumination beam having an optical imaging matching angle, and the optical imaging matching angle of the illumination beam is aligned with a visual angle of a pupil; The optical engine module is characterized in that the light valve is disposed on a transmission path of the illumination light beam, and the light valve modulates the illumination light beam into an image light beam.

2. The optical engine module of claim 1 , wherein the first diffusion element is a first microlens array or a first diffusion sheet.

3. The second diffusing element is a second microlens array or a second diffusion sheet; an optical reflecting mirror; 2. The optical engine module of claim 1, wherein the second microlens array or the second diffusion sheet is located between the optical reflection mirror and the polarizing beam splitting element, and the reflective surface of the optical reflection mirror faces away from the polarizing beam splitting element.

4. the second diffusing element includes a microstructured optical sheet; The optical engine module of claim 1 , wherein one surface of the microstructured optical sheet is curved and has a plurality of microstructures on the curved surface, and the microstructures diffuse the laser beam.

5. the second diffusing element includes a microstructured optical sheet; the microstructured optical sheet has a first optical surface and a second optical surface; 2. The optical engine module of claim 1, wherein the first optical surface is located between the polarizing beam splitting element and the second optical surface, the first optical surface being a surface on which a plurality of microlens elements are formed, and the second optical surface being a reflective surface.

6. The optical engine module of claim 5 , wherein the second optical surface is a curved surface.

7. the second optical surface is a flat surface; the second diffusing element further comprises an optical lens; The optical engine module of claim 5 , wherein the optical lens is located between the microstructured optical sheet and the polarizing beam splitting element.

8. the second diffusing element includes a microstructured optical sheet; the microstructured optical sheet has a first optical surface; The optical engine module of claim 1 , wherein the first optical surface is a surface of a micro-reflecting mirror array.

9. the optical engine module further includes a quarter wave plate; The optical engine module of claim 1 , wherein the quarter-wave plate is located between the second diffusing element and the polarizing beam splitting element.

10. 1. A projection device, comprising: the projection device includes an optical engine module and a projection lens assembly that provide an image beam; The optical engine module includes: a light source unit including a laser light emitting element and emitting a laser beam; a first diffusion element located on a transmission path of the laser beam; a polarizing beam splitting element located on a transmission path of the laser beam; a second diffusing element having at least one optical surface; a light valve; the first diffusion element is located between the polarizing beam splitting element and the light source unit, and no other element is disposed between the first diffusion element and the polarizing beam splitting element; the at least one optical surface reflects and diffuses the laser beam from the polarizing beam splitting element, and the laser beam is transmitted to the first diffusing element and the second diffusing element in sequence, so that the laser beam forms an illumination beam having an optical imaging matching angle, and the optical imaging matching angle of the illumination beam is aligned with a visual angle of a pupil; the light valve is disposed on a transmission path of the illumination light beam, and the light valve modulates the illumination light beam into an image light beam; The projection device, characterized in that the projection lens assembly is disposed on a transmission path of the image light beam, and projects the image light beam from the projection device.

11. The projection apparatus of claim 10 , wherein the projection lens assembly has a pupil.

12. The projection device of claim 10 , wherein the first diffusion element is a first microlens array or a first diffusion sheet.

13. The second diffusing element is a second microlens array or a second diffusion sheet; an optical reflecting mirror; 11. The projection device of claim 10, wherein the second microlens array or the second diffusion sheet is located between the optical reflection mirror and the polarizing beam splitting element, and the reflective surface of the optical reflection mirror faces away from the polarizing beam splitting element.

14. the second diffusing element includes a microstructured optical sheet; One surface of the microstructure optical sheet is a curved surface, and has a plurality of microstructures on the curved surface; The projection device of claim 10 , wherein the microstructures diffuse the laser beam.

15. the second diffusing element includes a microstructured optical sheet, the microstructured optical sheet having a first optical surface and a second optical surface; 11. The projection device of claim 10, wherein the first optical surface is located between the polarizing beam splitting element and the second optical surface, the first optical surface being a surface on which a plurality of microlens elements are formed, and the second optical surface being a reflective surface.

16. 16. The projection device of claim 15, wherein the second optical surface is a curved surface.

17. the second optical surface is a flat surface; the second diffusing element further comprises an optical lens; 16. The projection device of claim 15, wherein the optical lens is located between the microstructured optical sheet and the polarizing beam splitting element.

18. the second diffusing element includes a microstructured optical sheet; the microstructured optical sheet has a first optical surface; 11. The projection device of claim 10, wherein the first optical surface is a surface of a micro-reflective mirror array.

19. the projection device further includes a quarter wave plate; 11. The projection device of claim 10, wherein the quarter-wave plate is located between the second diffusing element and the polarizing beam-splitting element.

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