Optical structure for improving the illumination of an LCD projector

Abstract

The application discloses an optical structure for improving the lighting effect of an LCD projector, which comprises an LED light source (1), a first free-form surface lens (2), a free-form surface reflector (3), a second free-form surface lens (4), a polaroid (5) and a liquid crystal panel (6), and the LED light source (1), the first free-form surface lens (2), the free-form surface reflector (3), the second free-form surface lens (4), the polaroid (5) and the liquid crystal panel (6) are sequentially arranged along an optical axis. The first free-form surface lens, the free-form surface reflector and the second free-form surface lens are used for multiple light distribution and collimation of the light source, so that the utilization rate of the light source is maximally improved, the uniformity of the lighting and the collimation degree of the light are improved, the length of the lighting part is obviously shortened, the high-efficiency, uniform and collimated lighting of the LCD liquid crystal screen is realized by using a relatively simple structure, and the lighting part is miniaturized.

Description

Technical Field

[0001] This invention relates to the field of projectors, and more specifically to an optical structure for improving the illumination effect of an LCD projector. It utilizes two freeform lenses and one freeform mirror to distribute light from an LED light source, thereby improving the luminous efficiency, uniformity, and collimation of the LCD illumination, and significantly shortening the length of the illumination section. Background Technology

[0002] In commonly used LCD projectors, the illumination section typically uses light emitted from a light source that passes through a light cone and is then collimated by a Fresnel lens before illuminating the LCD. This method has the advantages of simple structure and low cost, but it also suffers from low luminous efficiency, poor uniformity, and inadequate collimation. Summary of the Invention

[0003] The technical problem to be solved by this invention is an optical structure for improving the illumination effect of an LCD projector. By using a structure of a first freeform surface lens, a freeform surface reflector, and a second freeform surface lens to distribute light from an LED light source, the light efficiency, uniformity, and collimation can be significantly improved, and the length of the illumination part can be significantly shortened, thereby improving the performance of the LCD projector.

[0004] The present invention is achieved through the following technical solution: an optical structure for improving the lighting effect of an LCD projector, comprising an LED light source, a first freeform surface lens, a freeform surface mirror, a second freeform surface lens, a polarizer, and a liquid crystal panel, wherein the LED light source, the first freeform surface lens, the freeform surface mirror, the second freeform surface lens, the polarizer, and the liquid crystal panel are arranged in sequence according to the optical axis.

[0005] As a preferred technical solution, the first freeform surface lens is located next to the LED light source, the freeform surface mirror is located between the first freeform surface lens and the second freeform surface lens, the optical axis is refracted at the freeform surface mirror, the polarizer is located behind the second freeform surface lens, and the LCD screen is located behind the polarizer.

[0006] As a preferred technical solution, the polarizer is a reflective polarizer.

[0007] As a preferred technical solution, the second freeform surface lens adopts a Fresnel lens, but other lens structures are also acceptable.

[0008] As a preferred technical solution, the first freeform lens is composed of two different freeform surfaces, so that light rays with different optical paths reaching the lens form an approximately rectangular and approximately collimated illumination spot, which then illuminates the freeform mirror.

[0009] The beneficial effects of this invention are as follows: A first freeform surface lens is provided after the LED light source. This lens is composed of two different freeform surfaces, allowing light rays with different optical paths reaching the lens to form an approximately rectangular and approximately collimated illumination spot. This spot then illuminates a freeform surface reflector, which distributes the light, further improving light utilization, collimation, and uniformity. A second freeform surface lens further optimizes uniformity and collimation. Finally, the light is illuminated onto the LCD after passing through a reflective polarizing film. Compared to the common LED light source illumination structure of LCD projectors, although the structure is more complex, it significantly improves the illumination effect and can significantly shorten the length of the illumination section, thus possessing certain economic value. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0012] Figure 2 This is a structural schematic diagram from another perspective of the present invention;

[0013] In the diagram: 1-LED light source; 2-first freeform surface lens; 3-freeform surface reflector; 4-second freeform surface lens; 5-reflective polarizer; 6-LCD panel. Detailed Implementation

[0014] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0015] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0016] like Figure 1 and Figure 2As shown, an optical structure for improving the lighting effect of an LCD projector according to the present invention includes an LED light source 1, a first freeform surface lens 2, a freeform surface mirror 3, a second freeform surface lens 4, a polarizer 5, and a liquid crystal panel 6. The LED light source 1, the first freeform surface lens 2, the freeform surface mirror 3, the second freeform surface lens 4, the polarizer 5, and the liquid crystal panel 6 are arranged sequentially along the optical axis.

[0017] The first freeform lens 2 is next to the LED light source 1, the freeform mirror 3 is located between the first freeform lens 2 and the second freeform lens 4, the optical axis is refracted at the freeform mirror 3, the polarizer is located behind the second freeform lens 4, and the liquid crystal panel 6 is located behind the polarizer.

[0018] In this embodiment, the polarizer 5 is a reflective polarizer. Of course, it can also be replaced or omitted by other forms of polarization structure.

[0019] The second freeform surface lens 4 is a Fresnel lens, but other lens structures can also be used instead.

[0020] Spherical, aspherical, and double conical surfaces are specific forms of freeform surfaces, and optical components located on the same optical axis achieve the best results.

[0021] The first freeform lens 2 is composed of two different freeform surfaces, allowing light rays arriving at the lens from different optical paths to form an approximately rectangular and collimated illumination spot, which then illuminates the freeform mirror 3. The light then passes through the freeform mirror, where it distributes the light spot, further improving light utilization, collimation, and uniformity. The second freeform lens further optimizes uniformity and collimation, and finally, after passing through a reflective polarizing film, the light illuminates the LCD screen. Compared to the common LED light source illumination structure of LCD projectors, although structurally more complex, this design significantly improves the illumination effect and can substantially shorten the length of the illumination section, thus possessing considerable economic value.

[0022] The optical principle is as follows:

[0023] The light emitted by the LED light source passes through the first freeform surface lens, which is a freeform surface structure with different curvatures in x and y. This freeform surface lens can collect and organize the light. The light emitted by the LED light source at different angles forms an approximately rectangular and approximately collimated illumination spot after passing through the first freeform surface lens. The light spot undergoes secondary light distribution through a freeform surface reflector, which further improves the uniformity and collimation of the light spot. Then, it is reflected onto the second freeform surface lens, which further improves the uniformity and collimation. Finally, it passes through a reflective polarizer to reach the LCD panel.

[0024] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived without inventive effort should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An optical structure for improving the illumination effect of an LCD projector, characterized in that: It includes an LED light source (1), a first freeform surface lens (2), a freeform surface mirror (3), a second freeform surface lens (4), a polarizer (5), and a liquid crystal panel (6). The LED light source (1), the first freeform surface lens (2), the freeform surface mirror (3), the second freeform surface lens (4), the polarizer (5), and the liquid crystal panel (6) are arranged in sequence according to the optical axis. The first freeform surface lens (2) is next to the LED light source (1), the freeform surface mirror (3) is located between the first freeform surface lens (2) and the second freeform surface lens (4), the optical axis is refracted at the freeform surface mirror (3), the polarizer is located behind the second freeform surface lens (4), and the liquid crystal panel (6) is located behind the polarizer. The polarizer (5) is a reflective polarizer; The second freeform surface lens (4) is a Fresnel lens; The first freeform lens (2) is composed of two different freeform surfaces, so that the light rays with different optical paths reaching the lens form an approximately rectangular and approximately collimated illumination spot, which then illuminates the freeform mirror (3).

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