Afocal optical element and projection device
By using a focus-free optical element of a monolithic lens in the projection device, the problem of high space and cost in the prior art is solved, and a compact projection device design and a low-cost beam shrinking effect are achieved.
Patent Information
- Application Number
- CN202310865071.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-14
- Publication Date
- 2025-01-14
AI Technical Summary
The design of focal-free optical component in existing projection devices requires a large space and high cost, making it difficult to achieve compact size and low-cost solutions.
The non-focus optical element using a single-chip lens has a convex side and a concave side of the object. The radius of curvature and refractive index meet specific conditions. It is used to shrink the beam in the lighting system to reduce space occupation and cost.
It is achieved without increasing costs, reducing the volume of the projection device and maintaining the parallelism of the light beams, reducing manufacturing costs and space requirements.
Smart Images
Figure CN119310789A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an optical element and an electronic device, and in particular to an afocal optical element and a projection device. Background Art
[0002] Projection devices are display devices used to produce large-size images. With the evolution and innovation of science and technology, they have been continuously improving. The imaging principle of projection devices 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 a projection lens to the projection target (for example, a screen or a wall) to form a projection image. In addition, the lighting system has also evolved from ultra-high-performance lamps (UHP lamps) and light-emitting diodes (LEDs) to the most advanced laser diode (LD) light source, as the market requires the brightness, color saturation, service life, and non-toxicity and environmental protection of projection devices, so as to make the internal configuration of the projection device more compact and the optical performance better.
[0003] In the current light combining system, the general afocal system design uses two lenses, one of which is a convex lens and the other is a concave lens. Through the design of the curvature and position of the two lenses, the diameter of the parallel light beam can be reduced. However, although the above design can greatly reduce the diameter of the parallel light beam, it takes up a large space and has a higher cost.
[0004] Therefore, it is necessary to design a new type of afocal optical element and projection device to overcome the above defects. Summary of the invention
[0005] The object of the present invention is to provide an afocal optical element and a projection device, which can occupy a smaller space and have a lower cost, so that the projection device has a smaller volume.
[0006] To achieve the above object, the present invention provides an afocal optical element and a projection device for converging a light beam, wherein the afocal optical element comprises an object side surface facing the object side and allowing the light beam to pass through, and an image side surface facing the image side and allowing the light beam to pass through;
[0007] The object side surface is a convex surface, the image side surface is a concave surface, and the afocal optical element has only one lens.
[0008] Preferably, the afocal optical element is a meniscus-shaped lens.
[0009] Preferably, the afocal optical element is a spherical lens.
[0010] Preferably, the afocal optical element is made of glass.
[0011] Preferably, the refractive index of the afocal optical element is greater than or equal to 1.70 and less than or equal to 1.90.
[0012] Preferably, the afocal optical element satisfies the following conditional formula:
[0013] 0.5≦R2 / R1<1, where R2 is the radius of curvature of the image side surface, and R1 is the radius of curvature of the object side surface.
[0014] Preferably, the afocal optical element satisfies the following conditional formula:
[0015] 0.5≦D2 / D1<1, wherein D2 is the beam diameter of the light beam after passing through the afocal optical element, and D1 is the beam diameter of the light beam before passing through the afocal optical element.
[0016] Preferably, the radius of curvature of the object side surface is greater than or equal to 4.1 and less than or equal to 5.2; the radius of curvature of the image side surface is greater than or equal to 2.8 and less than or equal to 3.9.
[0017] Preferably, the light beam is parallel light before entering the afocal optical element, and the light beam is also parallel light after passing through the afocal optical element.
[0018] Preferably, a projection device comprises:
[0019] A lighting system for providing a lighting beam, the lighting system comprising:
[0020] A light source module, providing a light beam; and
[0021] an afocal optical element, arranged on the transmission path of the light beam, for converging the light beam, the afocal optical element being an afocal optical element;
[0022] a light valve, disposed on a transmission path of the illumination light beam, for converting the illumination light beam into an image light beam; and
[0023] The projection lens is disposed on the transmission path of the image light beam and is used to project the image light beam out of the projection device.
[0024] Preferably, the light source module comprises a plurality of laser light emitting units, each providing a plurality of sub-beams to form the light beam, and the plurality of laser light emitting units are arranged in an array.
[0025] Compared with the prior art, in the afocal optical element and the projection device provided by the present invention, the afocal optical element is arranged on the transmission path of the light beam in the lighting system to reduce the light beam. The afocal optical element includes an object side surface facing the object side and allowing the light beam to pass through, and an image side surface facing the image side and allowing the light beam to pass through, wherein the object side surface is a convex surface and the image side surface is a concave surface. The afocal optical element has only one lens, so that, compared with the prior art that uses two optical lenses for reduction, the afocal optical element using a single optical lens can occupy a smaller space in the lighting system and has a lower cost, thereby making the projection device have a smaller volume. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a structural schematic diagram of a projection device according to an embodiment of the present invention;
[0027] Figure 2 FIG. 4 is a schematic structural diagram of an afocal optical element according to an embodiment of the present invention. DETAILED DESCRIPTION
[0028] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the following detailed description is given in conjunction with the embodiments.
[0029] Certain words are used in the specification and claims to refer to specific components. Those with ordinary knowledge in the field should understand that manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but rather use differences in components' functions as the criteria for distinction. The term "including" mentioned throughout the specification and claims is an open-ended term and should be interpreted as "including but not limited to".
[0030] Figure 1 This is a schematic diagram of a projection device according to an embodiment of the present invention. Figure 1 The present embodiment provides a projection device 10, including an illumination system 50, a light valve 60, and a projection lens 70. The illumination system 50 is used to provide an illumination beam LB. The light valve 60 is disposed on the transmission path of the illumination beam LB, and is used to convert the illumination beam LB into an 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 or a wall.
[0031] The lighting system 50 is used to provide an illumination beam LB. For example, in the present embodiment, the lighting system 50 is composed of a light source module 51, a diffusion element 52, a uniform light element 53, a reflection element 54, a beam splitter element 55 and / or a lens element 56, and is used to provide light of different wavelengths to form an image beam LI. The light source module 51 is used to provide a light beam L. In the present embodiment, the light source module 51 includes, for example, a plurality of laser light emitting units 57, which respectively provide a plurality of sub-beams L0 to form a light beam L, and the plurality of laser light emitting units 57 are arranged in an array. However, the present invention does not limit the type or form of the lighting system 50 in the projection device 10, and its detailed structure and implementation can be described later and sufficient teachings, suggestions and implementation instructions can be obtained from the general knowledge in the relevant technical field.
[0032] 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). In some embodiments, the light valve 60 may also be a transmissive light modulator such as a Transparent Liquid Crystal Panel, an Electro-Optical Modulator, a Magneto-Optic modulator, or an Acousto-Optic Modulator (AOM). The present invention does not limit the type and kind of the light valve 60. The detailed steps and implementation methods of the method for the light valve 60 to convert the illumination light beam LB into the image light beam LI can be sufficiently taught, suggested, and implemented by the common knowledge in the relevant technical field, and thus will not be described in detail.
[0033] The projection lens 70 includes, for example, a combination of one or more optical lenses with diopter, such as various combinations of non-planar lenses such as biconcave lenses, biconvex lenses, concave-convex lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses. In one embodiment, the projection lens 70 may also include a planar 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.
[0034] Figure 2 FIG. 1 is a schematic diagram of an afocal optical element according to an embodiment of the present invention. The afocal optical element 100 of this embodiment can be applied to at least Figure 1 The projection device 10 is shown, so it is used as an example in the following description. Figure 1 and Figure 2. The lighting system 50 includes an afocal optical element 100, which is arranged on the transmission path of the light beam L, and is used to reduce the light beam L. Specifically, in the present embodiment, the afocal optical element 100 is arranged on the transmission path of the light beam L from the light source module 51, and is located between the light source module 51 and the diffusion element 52, but the present invention is not limited to this. It should be noted that the afocal optical element 100 has only one lens, and the light beam L is parallel light before entering the afocal optical element 100, and the light beam L from the afocal optical element 100 is also parallel light. In other words, the present embodiment can achieve the purpose of reducing the light beam L by using a single optical lens. In this way, compared with the prior art that uses two optical lenses for reduction, it can occupy a smaller space in the lighting system 50 and has a lower cost, thereby making the projection device 10 have a smaller volume.
[0035] In detail, in the present embodiment, the afocal optical element 100 includes an object-side surface S1 facing the object side A1 and allowing the light beam L to pass through, and an image-side surface S2 facing the image side A2 and allowing the light beam L to pass through, wherein the object-side surface S1 is a convex surface, and the image-side surface S2 is a concave surface. In other words, the afocal optical element 100 is a meniscus-shaped lens. In the present embodiment, the afocal optical element 100 is a spherical lens, and its material can be glass, and its refractive index is, for example, greater than or equal to 1.70 and less than or equal to 1.90. In this way, when a higher refractive index material is used for manufacturing, the thickness required for the afocal optical element 100 can be thinner, so that a smaller volume can be achieved, and it is easy to manufacture, but the present invention is not limited to this. In addition, in the present embodiment, the afocal optical element 100 satisfies the conditional formula: 0.5≦R2 / R1<1, wherein R2 is the radius of curvature of the image-side surface S2, and R1 is the radius of curvature of the object-side surface S1. If the ratio of R2 to R1 is less than 0.5, the curvature radius of the image side S2 is too small and difficult to manufacture. In other words, under this condition, the afocal optical element 100 can be manufactured more easily, so that the lens has better stability and is not easy to break, and the manufacturing cost can be reduced.
[0036] Specifically, the radius of curvature of the object side surface S1 of the afocal optical element 100 is greater than or equal to 4.1 and less than or equal to 5.2, and the radius of curvature of the image side surface S2 is greater than or equal to 2.8 and less than or equal to 3.9. For example, in the present embodiment, the refractive index of the afocal optical element 100 is 1.834, the radius of curvature of the object side surface S1 is 4.67, and the radius of curvature of the image side surface S2 is 3.33, so the beam diameter D1 of the light beam L before the beam is reduced to the beam diameter D2 of the light beam L after the beam is reduced, and the ratio of the beam diameter D2 to the beam diameter D1 is 0.71. In this way, compared with the prior art that uses two optical lenses for beam reduction, the afocal optical element 100 of the present embodiment that uses a single optical lens can occupy a smaller space in the lighting system 50 and has a lower cost, thereby making the projection device 10 have a smaller volume.
[0037] In summary, in the afocal optical element and the projection device of the present invention, the afocal optical element is arranged on the transmission path of the light beam in the illumination system to reduce the light beam. The afocal optical element includes an object side surface facing the object side and allowing the light beam to pass through, and an image side surface facing the image side and allowing the light beam to pass through, wherein the object side surface is a convex surface and the image side surface is a concave surface. The afocal optical element has only one lens. In this way, compared with the prior art that uses two optical lenses for reduction, the afocal optical element using a single optical lens can occupy a smaller space in the illumination system and has a lower cost, thereby making the projection device have a smaller volume.
[0038] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, changes and modifications made without departing from the spirit and scope of the present invention are all within the scope of patent protection of the present invention.
Claims
1. An afocal optical element for converging a light beam, the afocal optical element comprising an object-side surface facing the object side and allowing the light beam to pass through, and an image-side surface facing the image side and allowing the light beam to pass through; The object side surface is a convex surface, the image side surface is a concave surface, and the afocal optical element has only one lens.
2. The afocal optical element according to claim 1, wherein: The afocal optical element is a meniscus-shaped lens.
3. The afocal optical element according to claim 1, wherein: The afocal optical element is a spherical lens.
4. The afocal optical element according to claim 1, wherein: The material of the afocal optical element is glass.
5. The afocal optical element according to claim 1, wherein: The refractive index of the afocal optical element is greater than or equal to 1.70 and less than or equal to 1.
90.
6. The afocal optical element according to claim 1, wherein: The afocal optical element satisfies the following conditional formula: 0.5≦R2 / R1<1, where R2 is the radius of curvature of the image side surface, and R1 is the radius of curvature of the object side surface.
7. The afocal optical element according to claim 1, wherein: The afocal optical element satisfies the following conditional formula: 0.5≦D2 / D1<1, wherein D2 is the beam diameter of the light beam after passing through the afocal optical element, and D1 is the beam diameter of the light beam before passing through the afocal optical element.
8. The afocal optical element according to claim 1, wherein: The radius of curvature of the object side surface is greater than or equal to 4.1 and less than or equal to 5.2; the radius of curvature of the image side surface is greater than or equal to 2.8 and less than or equal to 3.
9.
9. The afocal optical element according to claim 1, wherein: The light beam is parallel light before entering the afocal optical element, and is also parallel light after passing through the afocal optical element.
10. A projection device, comprising: A lighting system for providing a lighting beam, the lighting system comprising: A light source module, providing a light beam; and an afocal optical element, arranged on the transmission path of the light beam, for converging the light beam, wherein the afocal optical element is the afocal optical element according to any one of claims 1 to 9; a light valve, disposed on a transmission path of the illumination light beam, for converting the illumination light beam into an image light beam; and The projection lens is disposed on the transmission path of the image light beam and is used to project the image light beam out of the projection device.
11. The projection device according to claim 10, characterized in that: The light source module includes a plurality of laser light emitting units, each of which provides a plurality of sub-beams to form the light beam, and the plurality of laser light emitting units are arranged in an array.