CN116931358A - Illumination system and projection device - Google Patents

Abstract

The invention provides an illumination system, which includes a light source module, a first lens array, a light condensing element, a second lens array and a prism element. The light source module is used to provide illumination beams. The first lens array is arranged on the transmission path of the illumination beam. The light condensing element is arranged on the transmission path of the illumination beam. The first lens array is located between the light source module and the light condensing element. The second lens array is arranged on the transmission path of the illumination beam. The prism element is arranged on the transmission path of the illumination beam. The second lens array is located between the light condensing element and the prism element, wherein the surface area of the second lens array is larger than the surface area of the first lens array, so that the lighting system can improve the uniformity of the illumination beam and the uniformity of different colors. The present invention also refers to a projection device having such an illumination system.

Description

Lighting systems and projection devices

Technical field

The present invention relates to an optical system and a display device, and in particular to an illumination system and a projection device having the illumination system.

Background technique

The projection device is a display device used to produce large-area images. With the evolution and innovation of science and technology, it has been constantly improving. The imaging principle of the projection device is to convert the illumination beam generated by the lighting system into an image beam through a light valve, and then project the image beam through the projection lens onto the projection target (such as a screen or wall) to form a projection image .

In order to pursue a smaller projection device for micro-projection devices, which can be used on head-mounted displays, the lighting system of micro-projection devices has changed from the early R/G/B three-channel (Red/Green/Blue LED light beamsforming three pathways), gradually evolved into the current RB/G two channels (Red and Blue/Green LEDlight beams forming two pathways), or RGB one channel (Red and Blue and Green LEDlight beams forming one pathway). The above three architectures all use collimating lenses to parallel-incident light sources provided by light-emitting diodes to the lens array, and then focus the light beams on the lens array on the imaging element of the light valve through the condenser lens. However, in order to achieve the smallest volume design, the minimum light source will be used for the design. However, because some of the color light sources are one light source each, and their positions are diagonal to each other, the projected image will have obvious color unevenness.

The "Background Art" paragraph is only used to help understand the content of the present invention. Therefore, the content disclosed in the "Background Art" paragraph may contain some prior art that does not constitute prior art known to those skilled in the art. The content disclosed in the "Background Art" paragraph does not mean that the content or the problems to be solved by one or more embodiments of the present invention have been known or recognized by those skilled in the art before the application of the present invention.

Contents of the invention

The present invention provides an illumination system and a projection device, which can improve the uniformity of illumination beams and the uniformity of different colors.

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

In order to achieve one, part or all of the above objects or other objects, the present invention provides an illumination system, which includes a light source module, a first lens array, a light condensing element, a second lens array and a prism element. The light source module is used to provide illumination beams. The first lens array is arranged on the transmission path of the illumination beam. The light condensing element is arranged on the transmission path of the illumination beam. The first lens array is located between the light source module and the light condensing element. The second lens array is arranged on the transmission path of the illumination beam. The prism element is arranged on the transmission path of the illumination beam. The second lens array is located between the light condensing element and the prism element, wherein the surface area of the second lens array is greater than the surface area of the first lens array.

In order to achieve one, part or all of the above objects or other objects, the present invention further provides a projection device, which includes an illumination system, a light valve and a projection lens. A lighting system is used to provide an illumination beam. The illumination system includes a light source module, a first lens array, a light condensing element, a second lens array and a prism element. The light source module is used to provide illumination beams. The first lens array is arranged on the transmission path of the illumination beam. The light condensing element is arranged on the transmission path of the illumination beam. The first lens array is located between the light source module and the light condensing element. The second lens array is arranged on the transmission path of the illumination beam. The prism element is arranged on the transmission path of the illumination beam. The second lens array is located between the light condensing element and the prism element. The light valve is arranged on the transmission path of the illumination beam and is used to convert the illumination beam into an image beam. The projection lens is disposed on the transmission path of the image beam and is used to project the image beam out of the projection device, wherein the surface area of the second lens array is larger than the surface area of the first lens array.

Based on the above, embodiments of the present invention have at least one of the following advantages or effects. In the lighting system and projection device of the present invention, the lighting system includes a light source module, a first lens array, a light condensing element, a second lens array and a prism element. The first lens array is disposed between the light source module and the condensing element and is used to control the beam cross-sectional area size of the illumination beam provided by the light source module to match the surface size (surface area) of the light valve that receives the illumination beam, and the second lens array It is arranged between the light condensing element and the prism element and is used to change the light pattern of each color in the illumination beam and make it uniform. In this way, the uniformity of the illumination beam and the uniformity of different colors can be improved to prevent the human eye from seeing unevenness in the color light emitted by the light-emitting element.

In order to make the above-mentioned features and advantages of the present invention more obvious and understandable, embodiments are given below and described in detail with reference to the accompanying drawings.

Description of the drawings

FIG. 1 is a schematic diagram of a projection device according to an embodiment of the present invention.

Figure 2 is a schematic diagram of a lighting system according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a light source module according to an embodiment of the present invention.

4A to 4C are schematic diagrams of partial lens arrays of different embodiments.

FIG. 5 is a partially enlarged schematic diagram of the lighting system of FIG. 2 .

Figure 6 is a schematic diagram of a lighting system according to another embodiment of the present invention.

Detailed ways

The foregoing and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. Directional terms (eg, up, down, left, right, front or back, etc.) mentioned in the following embodiments are only for reference to the directions of additional views. Accordingly, the directional terms used are illustrative and not limiting of the invention.

FIG. 1 is a schematic diagram of a projection device according to an embodiment of the present invention. Please refer to Figure 1. In one embodiment, the projection device 10 may be applied to a head-mounted display. This embodiment provides a projection device 10 including an illumination system 100, a light valve 60 and a projection lens 70. Wherein, the lighting system 100 is used to provide an illumination beam LB. The light valve 60 is arranged on the transmission path of the illumination beam LB and is used to convert the illumination beam LB into the image beam LI. The projection lens 70 is disposed on the transmission path of the image beam LI, and is used to project the image beam LI out of the projection device 10 to a projection target (not shown), such as a screen, a wall, or a waveguide element of a head-mounted device.

In this embodiment, the light valve 60 is, for example, a reflective light modulator such as a Liquid Crystal On Silicon panel (LCoS panel) or a Digital Micro-mirror Device (DMD). The present invention does not limit the type and type of the light valve 60 . The light valve 60 converts the illumination beam LB from the illumination system 100 into the image beam LI. The detailed steps and implementation methods can be obtained from common knowledge in the field with sufficient teachings, suggestions and implementation instructions, and therefore will not be described again. In this embodiment, the number of the light valve 60 is one, for example, the projection device 10 uses a single digital micromirror element. The light valve 60 may also use a liquid crystal silicon-coated panel. In this embodiment, the projection device 10 further includes a protective cover 80 (see FIG. 2 ), which is used to prevent the light valve 60 from contacting dust and affecting the optical effect. The material of the protective cover 80 is, for example, glass or plastic.

The projection lens 70 includes, for example, a combination of one or more optical lenses with refractive power, such as various combinations of non-planar lenses such as biconcave lenses, biconvex lenses, meniscus lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses. In one embodiment, the projection lens 70 may further include a plane optical lens to project the image beam LI from the light valve 60 to the projection target in a reflective manner. The present invention does not limit the type and type of the projection lens 70 .

Figure 2 is a schematic diagram of a lighting system according to an embodiment of the present invention. FIG. 3 is a schematic diagram of a light source module according to an embodiment of the present invention. Please refer to Figure 2 and Figure 3. The lighting system 100 of this embodiment can be applied to at least the projection device 10 shown in FIG. 1 , so the following description takes this as an example. In this embodiment, the lighting system 100 includes a light source module 110, a first lens array 120, a light condensing element 130, a second lens array 140 and a prism element 150. The light source module 110 is used to provide illumination beam LB. In this embodiment, the light source module 110 includes a light-emitting element 112 and a collimating lens group 114. The light-emitting element 112 is, for example, an integrated light-emitting diode that provides red light, green light and blue light. Specifically, the light-emitting element 112 is arranged with red, green, green and blue light-emitting diodes, and the red and blue light-emitting diodes are diagonal to each other, and the two green light-emitting diodes are diagonal to each other. , as shown in Figure 3. Therefore, the design of the smallest volume can be achieved, but the present invention is not limited thereto. In this embodiment, the collimating lens group 114 includes at least one optical lens. The collimating lens group 114 is used to provide the parallel illumination beam LB to the first lens array 120. The invention is not limited thereto.

The first lens array 120 is disposed on the transmission path of the illumination beam LB and is used to control the beam cross-sectional area size of the illumination beam LB provided by the light source module 110 to match the surface size (surface area) of the light valve 60 that receives the illumination beam LB. For example, the beam cross-sectional area size of the illumination beam LB passing through the first lens array 120 is equal to or approximately the surface size of the light valve 60 that receives the illumination beam LB.

The first lens array 120 includes a plurality of microlenses, which may be located on one side of the first lens array 120 or on two opposite sides of the first lens array 120 . The invention is not limited thereto.

The light condensing element 130 is arranged on the transmission path of the illumination beam LB, and the first lens array 120 is located between the light source module 110 and the light condensing element 130 . In this embodiment, the light condensing element 130 has a reflective surface 132, for example, coated with a reflective film, for reflecting the illumination beam LB to be transmitted to the second lens array 140.

The second lens array 140 is arranged on the transmission path of the illumination beam LB and is used to change the light pattern of each color (red, green and blue) in the illumination beam LB and make it uniform, thereby improving the uniformity and difference of the illumination beam LB. The uniformity of the color is to prevent the human eye from seeing unevenness in the color light emitted by the light-emitting element 112 . The second lens array 140 includes a plurality of microlenses located on opposite sides of the second lens array 140 . In this embodiment, physically, the surface area of the second lens array 140 is larger than the surface area of the first lens array 120 . In addition, the beam area of the light incident surface of the second lens array 140 that receives the illumination beam LB will also be larger than the beam area of the light incident surface of the first lens array 120 that receives the illumination beam LB.

4A to 4C are schematic diagrams of partial lens arrays of different embodiments. Please refer to Figure 2, Figure 4A to Figure 4C. In different embodiments, the microlenses M of the first lens array 120 and the second lens array 140 can have different arrangement designs according to different situations. For example, as shown in FIG. 4A , the microlenses M of the first lens array 120 and the second lens array 140 may be in a hexagonal arrangement (or circular arrangement). Alternatively, as shown in FIG. 4B , the microlenses M1 of the first lens array 120 and the second lens array 140 may be arranged in a rectangular shape. Alternatively, as shown in FIG. 4C , the microlenses M2 of the first lens array 120 and the second lens array 140 may be arranged in a spiral (for convenience of display, FIG. 4C only shows the arrangement positions), but the invention is not limited thereto.

FIG. 5 is a partially enlarged schematic diagram of the lighting system of FIG. 2 . Please refer to Figure 2 and Figure 5. The prism element 150 is arranged on the transmission path of the illumination beam LB, and the second lens array 140 is located between the light condensing element 130 and the prism element 150 . The prism element 150 is, for example, a total internal reflection prism (TIR prism), used to guide the illumination beam LB to the light valve 60 and guide the image beam LI to the projection lens 70 (see FIG. 1 ). To further explain, the prism element 150 has a first surface and a light exit surface. The first surface of the prism element 150 faces the second lens array 140 , and the light exit surface of the prism element 150 faces the light valve 60 . The first surface of the prism element 150 is used to receive the illumination beam LB, and the illumination beam LB enters the prism element 150 and is transmitted to the light valve 60 . When the light valve 60 converts the illumination beam LB into the image beam LI, the image beam LI enters the prism element 150 again, and the image beam LI is reflected by the first surface of the prism element 150 and leaves the prism element 150 and is transmitted to the projection lens 70 .

In addition, in this embodiment, the extension direction of the second lens array 140 (this extension direction is perpendicular to the normal direction of the surface of the second lens array 140) and the extension direction of the light exit surface of the prism element 150 (this extension direction is perpendicular to The normal direction of the surface of the light valve 60 has an included angle A. The light exit surface of the prism element 150 is parallel to the surface of the light valve 60 . Specifically, the illumination system 100 may further include a spacer 160 with a distance between the spacer 160 and the second lens array 140 .

The spacer 160 is disposed between the second lens array 140 and the prism element 150, and its purpose is to prevent the illumination beam LB from generating an optical path difference in the air layer, thereby causing a degradation in the quality of the projected image. It is worth mentioning that in this embodiment, the size of the second lens array 140 (ie, the optical area) can be determined based on the surface size of the light valve 60 and its light collection angle. In this way, the light usage efficiency can be improved, as shown in Figure 5, thereby improving the uniformity of the illumination beam LB.

Figure 6 is a schematic diagram of a lighting system according to another embodiment of the present invention. Please refer to Figure 6. The lighting system 100A of this embodiment is similar to the lighting system 100 shown in FIG. 2 . The difference between the two is that in this embodiment, the collimating lens group 114A of the light source module 110A includes a compound parabolic concentrator (CPC) for transmitting light emitted by the light-emitting element 112 at different angles. The curved surface of a compound parabolic concentrator becomes parallel light. Furthermore, the first lens array 120A is directly connected to the compound parabolic condenser. Therefore, the volume of the lighting system 100A can be further saved and the lighting system 100A has good optical effects. In another embodiment, the first lens array 120A can also be directly connected to the light incident surface of the light condensing element 130 . In this way, the uniformity of the illumination beam and the uniformity of different colors can be improved to prevent the human eye from seeing unevenness in the color light emitted by the light-emitting element 112 .

To sum up, in the lighting system and projection device of the present invention, the lighting system includes a light source module, a first lens array, a light condensing element, a second lens array and a prism element. The first lens array is disposed between the light source module and the condensing element, and is used to control the beam cross-sectional area size of the illumination beam provided by the light source module to match the surface area size of the light valve that receives the illumination beam, and the second lens array is disposed between Between the light condensing element and the prism element, it is used to change the light pattern of each color in the illumination beam and make it uniform, and the surface area of the second lens array is larger than the surface area of the first lens array. In this way, the uniformity of the illumination beam and the uniformity of different colors can be improved to prevent the human eye from seeing unevenness in the color light emitted by the light-emitting element.

The above are only preferred embodiments of the present invention, and should not be used to limit the scope of the present invention. That is, all simple equivalent changes and modifications made in accordance with the claims and description of the present invention are still covered by the patent of the present invention. In the range. In addition, any embodiment or claim of the present invention does not necessarily achieve all the purposes, advantages or features disclosed in the present invention. In addition, the abstract of the description and the invention title are only used to assist patent document retrieval and are not used to limit the scope of rights of the invention. In addition, terms such as “first” and “second” mentioned in this specification or claims are only used to name elements or to distinguish different embodiments or scopes, and are not used to limit the number of elements. upper or lower limit.

List of reference signs

10:Projection device

60:Light valve

70:Projection lens

80:Protective cover

100,100A: Lighting system

110,110A:Light source module

112:Light-emitting component

114,114A:Collimation lens group

120,120A: First lens array

130: Condensing element

132: Reflective surface

140: Second lens array

150:Prism element

160: Spacer

A: Angle

LB: lighting beam

LI: image beam

M, M1, M2: microlens.

Claims (20)

1. An illumination system, characterized in that the illumination system includes a light source module, a first lens array, a light condensing element, a second lens array and a prism element, wherein: The light source module is used to provide an illumination beam; The first lens array is arranged on the transmission path of the illumination beam; The light condensing element is arranged on the transmission path of the illumination beam, and the first lens array is located between the light source module and the light condensing element; The second lens array is arranged on the transmission path of the illumination beam; The prism element is arranged on the transmission path of the illumination beam, and the second lens array is located between the light condensing element and the prism element, wherein the surface area of the second lens array is larger than that of the first lens array. The surface area of the lens array. 2. The lighting system according to claim 1, wherein the second lens array includes a plurality of microlenses located on opposite sides of the second lens array. 3. The lighting system according to claim 1, wherein the second lens array includes a plurality of microlenses, and the plurality of microlenses are arranged in a hexagonal, rectangular or spiral arrangement. 4. The lighting system according to claim 1, wherein the extension direction of the second lens array and the extension direction of the light exit surface of the prism element have an included angle. 5. The lighting system according to claim 1, wherein the light source module includes a light-emitting element and a collimating lens group, wherein the light-emitting element provides red light, green light and blue light. 6. The lighting system according to claim 1, wherein the light-emitting element is an arrangement of red, green, green and blue light-emitting diodes. 7. The lighting system according to claim 1, wherein the collimating lens group includes at least one optical lens. 8. The illumination system of claim 1, wherein the collimating lens group includes a compound parabolic concentrator. 9. The illumination system of claim 8, wherein the first lens array is directly connected to the compound parabolic concentrator. 10. The illumination system according to claim 1, wherein the light condensing element has a reflective surface for reflecting the illumination beam to pass to the second lens array. 11. A projection device, characterized in that the projection device includes an illumination system, a light valve and a projection lens, wherein: The illumination system is used to provide an illumination beam. The illumination system includes a light source module, a first lens array, a light condensing element, a second lens array and a prism element, wherein: The light source module is used to provide an illumination beam; The first lens array is arranged on the transmission path of the illumination beam; The light condensing element is arranged on the transmission path of the illumination beam, and the first lens array is located between the light source module and the light condensing element; The second lens array is arranged on the transmission path of the illumination beam; The prism element is arranged on the transmission path of the illumination beam, and the second lens array is located between the light condensing element and the prism element; The light valve is arranged on the transmission path of the illumination beam and is used to convert the illumination beam into an image beam; The projection lens is disposed on the transmission path of the image beam and is used to project the image beam out of the projection device, wherein the surface area of the second lens array is larger than the surface area of the first lens array. 12. The projection device according to claim 11, wherein the second lens array includes a plurality of microlenses located on opposite sides of the second lens array. 13. The projection device according to claim 11, wherein the second lens array includes a plurality of microlenses, and the plurality of microlenses are arranged in a hexagonal, rectangular or spiral arrangement. 14. The projection device according to claim 11, wherein the extension direction of the second lens array and the extension direction of the light exit surface of the prism element have an included angle. 15. The projection device according to claim 11, wherein the light source module includes a light-emitting element and a collimating lens group, wherein the light-emitting element provides red light, green light and blue light. 16. The projection device according to claim 11, wherein the light-emitting element is an arrangement of red, green, green and blue light-emitting diodes. 17. The projection device according to claim 11, wherein the collimating lens group includes at least one optical lens. 18. The projection device according to claim 11, wherein the collimating lens group includes a compound parabolic condenser. 19. The projection device of claim 18, wherein the first lens array is directly connected to the compound parabolic concentrator. 20. The projection device according to claim 11, wherein the light condensing element has a reflective surface for reflecting the illumination beam to pass to the second lens array.