High-efficiency projector light path

Abstract

A high-efficiency projector light path belongs to the technical field of projection and comprises an LED, a collimation system, a polarization beam splitter, a 1 / 4 wave plate, a first reflective mirror, a second reflective mirror, an LCD, a Fresnel lens and a lens. The LED is used for emitting non-polarized light rays; the collimation system comprises two positive lenses, one is a spherical lens, and the other is an aspherical lens; the polarization beam splitter is used for splitting unpolarized light emitted by the LED into S-direction polarization state transmitted light and P-direction polarization state first reflected light; the first reflected light passes through the 1 / 4 wave plate, is reflected by the first reflective mirror, passes through the 1 / 4 wave plate again, and is converted into second reflected light in an S-direction polarization state after the polarization state is rotated by 90 degrees; the first reflected light passes through the 1 / 4 wave plate twice, the polarization state of the first reflected light is rotated by 90 degrees, the first reflected light is changed into the second reflected light in the polarization state in the S direction, and the second reflected light and transmission light can be received by the LCD together, so that the problems that a polarizer of the LCD absorbs 50% of energy, the light utilization efficiency of a light path of the projector is low, and the working temperature of the liquid crystal is high are solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of projection, in particular to a high-efficiency projector optical path. Background Art

[0002] Currently, single-chip LCD projectors use collimated LEDs as their light source, illuminating the LCD directly afterward. Because the light is unpolarized, 50% of the energy passing through the LCD is absorbed by the LCD's polarizer. This absorbed energy is converted into heat, resulting in low light utilization efficiency in the projector's optical path and high operating temperatures for the LCD. Therefore, a new solution is urgently needed to address this issue. Summary of the Invention

[0003] The problem to be solved by the present invention is to reduce the absorption of light by LCD by changing the polarization state of incident light.

[0004] A high-efficiency projector optical path includes an LED, a collimation system, a polarization beam splitter, a quarter-wave plate, a first reflector, a second reflector, an LCD, a Fresnel lens, and a lens;

[0005] The LED is used to emit unpolarized light;

[0006] The collimating system includes two positive lenses, one is a spherical lens and the other is an aspherical lens;

[0007] The polarization beam splitter is used to split the unpolarized light emitted by the LED into transmitted light with an S-direction polarization state and first reflected light with a P-direction polarization state;

[0008] The first reflected light passes through the quarter wave plate and is reflected by the first reflector, and then passes through the quarter wave plate again. After the polarization state is rotated by 90 degrees, it is converted into the second reflected light with S-direction polarization state;

[0009] The second reflector is used to change the direction of the second reflected light so that it is combined with the transmitted light S in the same propagation direction and enters the LCD;

[0010] The LCD is used to display images;

[0011] The Fresnel lens is a field lens that focuses the image onto the lens.

[0012] The lens magnifies the image on the LCD and projects it onto a receiving surface.

[0013] The beneficial effects of the present application are as follows: the quarter-wave plate converts the light reflected by the polarization beam splitter into transmitted light and first reflected light; the first reflected light passes through the quarter-wave plate, is reflected by the first reflector, passes through the quarter-wave plate again, and is polarized by a rotation of 90° before being converted into second reflected light; the second reflector 6 is used to change the direction of the reflected light P2 so that it is combined with the transmitted light in the same propagation direction and enters the LCD 7. Because the first reflected light passes through the quarter-wave plate twice, its polarization state is rotated by 90°, becoming the second reflected light with an S-direction polarization state, which can be received by the LCD together with the transmitted light, thereby avoiding the LCD polarizer absorbing 50% of the energy, which in turn leads to low light utilization efficiency of the projector optical path and high operating temperature of the liquid crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural diagram of the optical path of a high-efficiency projector of the present application. DETAILED DESCRIPTION

[0015] Hereinafter, the embodiments of the present application will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0016] In order to make the purpose, technical solutions and advantages of this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and do not constitute a limitation of this application.

[0017] A high-efficiency projector optical path, such as Figure 1 As shown, it includes LED 1, collimation system 2, polarization beam splitter 3, 1 / 4 wave plate 4, first reflector 5, second reflector 6, LCD 7, Fresnel lens 8 and lens 9;

[0018] The LED 1 is used to emit unpolarized light;

[0019] The collimating system 2 includes two positive lenses, one is a spherical lens and the other is an aspherical lens;

[0020] The polarization beam splitter 3 is used to split the unpolarized light emitted by the LED 1 into the transmitted light 100 with the polarization state in the S direction and the first reflected light 200 with the polarization state in the P direction;

[0021] The first reflected light 200 passes through the quarter wave plate 4 and is reflected by the first reflector 5, and then passes through the quarter wave plate 4 again. After the polarization state is rotated by 90°, it is converted into the second reflected light 300 with the polarization state in the S direction;

[0022] The second reflector 6 is used to change the direction of the second reflected light 300 so that it is combined with the transmitted light S in the same propagation direction and enters the LCD 7;

[0023] The LCD 7 is used to display images;

[0024] The Fresnel lens 8 is a field lens that focuses the image onto the lens 9 .

[0025] The lens 9 magnifies the image on the LCD 7 and projects it onto a receiving surface.

[0026] Since LCD 7 can only receive light polarized in the same vibration direction, all unpolarized light from LED 1 must be converted into light with the same polarization state. To address this issue, a quarter-wave plate 4 is added. Based on the principle that light passing through the quarter-wave plate 4 twice rotates its polarization state by 90°, the LED 1 of the present invention emits unpolarized light. The collimation system 2 comprises two positive lenses: a spherical lens that enters the first lens and an aspheric lens that enters the second lens. A polarization beam splitter 3 separates the unpolarized light emitted by LED 1 into transmitted light 100 polarized in the S direction and first reflected light 200 polarized in the P direction. After passing through the quarter-wave plate 4, the reflected light 200 is reflected by a first reflector 5, which redirects the reflected light 200 to facilitate subsequent light combination. After passing through the quarter-wave plate 4 again, its polarization state is rotated by 90°, converting it into second reflected light 300 polarized in the S direction. A second reflector 6 redirects the second reflected light 300 so that it is combined with the transmitted light 100 in the same propagation direction and enters LCD 7. The LCD 7 is used to display images. The polarization state of the LCD 7 polarizer is consistent with the incident light. The Fresnel lens 8 is a field lens that improves the efficiency of light path utilization. The lens 9 magnifies the image displayed by the LCD 7 and projects it onto the receiving surface.

[0027] Finally, the present invention should explain that: the above embodiments are detailed descriptions of the technical solutions of the present invention, and are not limited to the aforementioned embodiments. Those skilled in the art should understand that modifications or replacements of the features and parameters in the aforementioned embodiments do not depart from the spirit and scope of the technical solutions of the aforementioned embodiments.

Claims

1. A high-efficiency projector optical path, characterized by: It includes an LED (1), a collimation system (2), a polarization beam splitter (3), a quarter wave plate (4), a first reflector (5), a second reflector (6), an LCD (7), a Fresnel lens (8) and a lens (9); The LED (1) is used to emit unpolarized light; The collimating system (2) includes two positive lenses, one is a spherical lens and the other is an aspherical lens; The polarization beam splitter (3) is used to split the unpolarized light emitted by the LED (1) into transmitted light (100) in an S-direction polarization state and first reflected light (200) in a P-direction polarization state; The first reflected light (200) passes through the quarter wave plate (4), is reflected by the first reflector (5), passes through the quarter wave plate (4) again, and is converted into the second reflected light (300) with an S-direction polarization state after the polarization state is rotated by 90°. The second reflector (6) is used to change the direction of the second reflected light (300) so that it is combined with the transmitted light S in the same propagation direction and enters the LCD (7); The LCD (7) is used to display images; The Fresnel lens (8) is a field lens that focuses the image onto the lens (9).

2. The high-efficiency projector optical path according to claim 1, characterized in that: The lens (9) magnifies the image on the LCD (7) and projects it onto a receiving surface.

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