LCD projection optical path structure

Abstract

The utility model relates to a kind of LCD projection light path structure, it includes light source, brightening glass, rear fresnel lens, first polaroid, LCD screen, second polaroid, front fresnel lens, reflector and projection lens sequentially arranged along the direction of light propagation, brightening glass is attached with polarized brightening film, the polarization angle of polarized brightening film is same with the polarization angle of first polaroid, the polarization angle of second polaroid is different from the polarization angle of first polaroid by 90 degrees;The light path structure uses 4.5-5.7 inch LCD screen, while matching appropriate focal length rear fresnel lens and front fresnel lens, to make full use of marginal light, with higher light utilization and brightness uniformity. By setting brightening glass between rear fresnel lens and light source, only S light is incident on rear fresnel lens when light source emits light, so as to reduce the light received on rear fresnel lens, conducive to temperature reduction, avoid rear fresnel lens to be soft, ensure brightness and uniformity.

Description

Technical Field

[0001] This utility model relates to the field of optical projection technology, and in particular to an LCD projection optical path structure. Background Technology

[0002] LCDs, which require light polarization for display, generally have low transmittance, especially the common single-panel LCD projectors, which have a transmittance of only about 5-8%. This results in low brightness in current LCD projector optical engines. The most direct solution to improve the brightness of an LCD projector optical engine is to increase the power of the illumination source. However, increasing the power of the source also generates a lot of heat, causing the temperature of the optical components to rise significantly. Commonly used optical components in projectors, such as Fresnel lenses, are made of PMMA material. When the temperature exceeds 80°C, they gradually soften and deform, resulting in reduced brightness and uniformity. Therefore, there is an urgent need to provide a solution to these problems. Utility Model Content

[0003] Therefore, the purpose of this utility model is to overcome the shortcomings of the prior art and provide an LCD projection optical path structure.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] An LCD projection optical path structure includes a light source, a brightness enhancement glass, a rear Fresnel lens, a first polarizer, an LCD screen, a second polarizer, a front Fresnel lens, a reflector, and a projection lens arranged sequentially along the light propagation direction. A polarizing brightness enhancement film is attached to the brightness enhancement glass. The polarization angle of the polarizing brightness enhancement film is the same as that of the first polarizer, and the polarization angle of the second polarizer differs from that of the first polarizer by 90 degrees.

[0006] The LCD screen is 4.5-5.7 inches in size, the rear Fresnel lens has a focal length of 90-110mm, the front Fresnel lens has a focal length of 120-150mm, and the reflector is tilted at 45° to reflect the light emitted from the front Fresnel lens by 90° before it enters the projection lens.

[0007] In one embodiment, the light source includes an LED emitter and a focusing funnel, with the LED emitter disposed at the light inlet of the focusing funnel and the rear Fresnel lens disposed at the light outlet of the focusing funnel.

[0008] In one embodiment, the length of the light inlet is 14.5-16.5 mm and the width is 10.5-14.5 mm; the length of the light outlet is 95-105 mm and the width is 55-60 mm; and the distance between the light inlet and the light outlet is 65-70 mm.

[0009] In one embodiment, the LED emitter is a COB packaged light source, the power of the LED emitter is 80-120W, the length of the emitting surface of the LED emitter is 14-16mm, and the width is 10-14mm.

[0010] As one implementation method, a reflective film is provided inside the focusing funnel.

[0011] In one embodiment, the distance between the brightness enhancement glass and the light outlet of the focusing funnel is 0-5mm, the distance between the rear Fresnel lens and the brightness enhancement glass is 0.1-5mm, the distance between the first polarizer and the rear Fresnel lens is 0-5mm, the distance between the second polarizer and the LCD screen is 5-10mm, and the distance between the front Fresnel lens and the LCD screen is 10-15mm.

[0012] In one embodiment, the length of the first polarizer is 100-110 mm and the width is 60-65 mm.

[0013] In one embodiment, the second polarizer has a length of 100-110 mm and a width of 60-65 mm.

[0014] In one embodiment, the front Fresnel lens has a length of 55.20-82.80 mm, a width of 32.80-49.20 mm, and a thickness of 1.20-1.80 mm.

[0015] In one embodiment, the length of the rear Fresnel lens is 52.00-78.00 mm, the width is 29.60-44.40 mm, and the thickness is 1.20-1.80 mm.

[0016] This optical path structure uses a 4.5-5.7 inch LCD screen to form the projected image, achieving miniaturization of a single-chip LCD projector. It also incorporates a rear Fresnel lens and a front Fresnel lens with appropriate focal lengths to fully utilize edge light, resulting in high light utilization and brightness uniformity. Furthermore, by placing a brightness enhancement glass between the rear Fresnel lens and the light source, the polarizing brightness enhancement film on the glass reflects P-light and transmits S-light. Thus, when the light source emits light, only S-light is incident on the rear Fresnel lens, reducing the amount of light received on the lens, which helps lower the temperature, prevents the rear Fresnel lens from softening, and ensures brightness and uniformity.

[0017] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the LCD projection optical path structure in the embodiments of this application;

[0019] Figure 2 This is a schematic diagram of the focusing funnel in the embodiments of this application;

[0020] Figure 3 This is a schematic diagram of the focusing funnel in the embodiments of this application;

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Light source; 11. LED emitter; 12. Concentrating funnel; 121. Light inlet; 122. Light outlet; 2. Brightness enhancement glass; 3. Rear Fresnel lens; 4. First polarizer; 5. LCD screen; 6. Second polarizer; 7. Front Fresnel lens; 8. Reflector; 9. Projection lens. Detailed Implementation

[0023] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention and are mainly used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention.

[0024] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "left", "right", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this utility model.

[0025] Please see Figures 1 to 3This embodiment provides an LCD projection optical path structure, which includes a light source 1, a brightness enhancement glass 2, a rear Fresnel lens 3, a first polarizer 4, an LCD screen 5, a second polarizer 6, a front Fresnel lens 7, a reflector 8, and a projection lens 9 arranged sequentially along the light propagation direction. A polarizing brightness enhancement film is attached to the brightness enhancement glass 2. The polarization angle of the polarizing brightness enhancement film is the same as that of the first polarizer 4, while the polarization angle of the second polarizer 6 differs from that of the first polarizer 4 by 90 degrees. The liquid crystal in the LCD screen can change the polarization angle of the light. Depending on the voltage applied to the LCD screen, the polarization angle of the light can be changed within the range of 0-90°. When displaying a completely white image, light enters the LCD screen through the first polarizer. An appropriate voltage is applied to the liquid crystal in the LCD screen to change the polarization angle of the light by 90 degrees, and the light exits through the second polarizer. When displaying a completely black image, no voltage is applied to the liquid crystal, the polarization angle of the light in the LCD screen does not change, and the light is intercepted by the second polarizer and does not exit.

[0026] The LCD screen 5 has a size of 4.5-5.7 inches, the rear Fresnel lens 3 has a focal length of 90-110mm, the front Fresnel lens 7 has a focal length of 120-150mm, and the reflector 8 is tilted at 45° to reflect the light emitted from the front Fresnel lens 7 by 90° before it enters the projection lens 9.

[0027] This optical path structure uses a 4.5-5.7 inch LCD screen 5 to form the projected image, achieving miniaturization of the single-chip LCD projector. It is paired with a rear Fresnel lens 3 and a front Fresnel lens 7 with appropriate focal lengths to fully utilize edge light, resulting in high light utilization and brightness uniformity. Furthermore, by placing a brightness enhancement glass 2 between the rear Fresnel lens 3 and the light source 1, the polarizing brightness enhancement film on the glass 2 reflects P-light and transmits S-light. Thus, when the light source 1 emits light, only S-light is incident on the rear Fresnel lens 3, reducing the amount of light received on the rear Fresnel lens 3. This helps reduce temperature, prevents the rear Fresnel lens 3 from softening, and ensures brightness and uniformity.

[0028] The light source 1 includes an LED emitter 11 and a focusing funnel 12. The focusing funnel 12 has an opposing light inlet 121 and a light outlet 122. The size of the light inlet 121 is smaller than that of the light outlet 122, so that the focusing cavity inside the focusing funnel 12 has a trapezoidal structure. A reflective film is provided inside the focusing funnel 12 to reflect and concentrate the incident light, so that the light is emitted in a roughly uniform and parallel manner.

[0029] The LED emitter 11 is disposed at the light inlet 121 of the light-concentrating funnel 12, and the rear Fresnel lens 3 is disposed at the light outlet 122 of the light-concentrating funnel 12.

[0030] Wherein, the length L1 of the light inlet 121 is 14.5-16.5mm and the width W1 is 10.5-14.5mm; the length L2 of the light outlet 122 is 95-105mm and the width W2 is 55-60mm; the distance D1 between the light inlet 121 and the light outlet 122 is 65-70mm.

[0031] In this embodiment, the LED emitter 11 is a COB packaged light source 1, the power of the LED emitter 11 is 80-120W, the length of the light-emitting surface of the LED emitter 11 is 14-16mm, and the width is 10-14mm, to ensure sufficient light brightness.

[0032] Preferably, the distance between the brightness enhancement glass 2 and the light outlet 122 of the focusing funnel 12 is 0-5mm, the distance between the rear Fresnel lens 3 and the brightness enhancement glass 2 is 0.1-5mm, the distance between the first polarizer 4 and the rear Fresnel lens 3 is 0-5mm, the distance between the second polarizer 6 and the LCD screen 5 is 5-10mm, and the distance between the front Fresnel lens 7 and the LCD screen 5 is 10-15mm. Maintaining a reasonable spacing improves overall heat dissipation efficiency. Simultaneously, the gap between the brightness enhancement glass 2 and the rear Fresnel lens 3 allows for further temperature reduction of the rear Fresnel lens 3 through air cooling.

[0033] Preferably, the first polarizer 4 has a length of 100-110 mm and a width of 60-65 mm.

[0034] Preferably, the second polarizer 6 has a length of 100-110 mm and a width of 60-65 mm.

[0035] In this embodiment, the front Fresnel lens 7 has a length of 55.20-82.80 mm, a width of 32.80-49.20 mm, and a thickness of 1.20-1.80 mm. The rear Fresnel lens 3 has a length of 52.00-78.00 mm, a width of 29.60-44.40 mm, and a thickness of 1.20-1.80 mm.

[0036] The embodiments described above are merely examples of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.

Claims

1. An LCD projection optical path structure, characterized in that, The device includes a light source, a brightness enhancement glass, a rear Fresnel lens, a first polarizer, an LCD screen, a second polarizer, a front Fresnel lens, a reflector, and a projection lens arranged sequentially along the direction of light propagation. A polarizing brightness enhancement film is attached to the brightness enhancement glass. The polarization angle of the polarizing brightness enhancement film is the same as that of the first polarizer, and the polarization angle of the second polarizer differs from that of the first polarizer by 90 degrees. The LCD screen is 4.5-5.7 inches in size, the rear Fresnel lens has a focal length of 90-110mm, the front Fresnel lens has a focal length of 120-150mm, and the reflector is tilted at 45° to reflect the light emitted from the front Fresnel lens by 90° before it enters the projection lens.

2. The LCD projection optical path structure according to claim 1, characterized in that: The light source includes an LED emitter and a focusing funnel. The LED emitter is located at the light inlet of the focusing funnel, and the rear Fresnel lens is located at the light outlet of the focusing funnel.

3. The LCD projection optical path structure according to claim 2, characterized in that: The length of the light inlet is 14.5-16.5 mm and the width is 10.5-14.5 mm; the length of the light outlet is 95-105 mm and the width is 55-60 mm; the distance between the light inlet and the light outlet is 65-70 mm.

4. The LCD projection optical path structure according to claim 2, characterized in that: The LED emitter is a COB packaged light source with a power of 80-120W. The length of the emitting surface of the LED emitter is 14-16mm and the width is 10-14mm.

5. The LCD projection optical path structure according to claim 2, characterized in that: A reflective film is installed inside the focusing funnel.

6. The LCD projection optical path structure according to claim 2, characterized in that: The distance between the brightness enhancement glass and the light outlet of the focusing funnel is 0-5mm, the distance between the rear Fresnel lens and the brightness enhancement glass is 0.1-5mm, the distance between the first polarizer and the rear Fresnel lens is 0-5mm, the distance between the second polarizer and the LCD screen is 5-10mm, and the distance between the front Fresnel lens and the LCD screen is 10-15mm.

7. The LCD projection optical path structure according to any one of claims 1-6, characterized in that: The first polarizer has a length of 100-110 mm and a width of 60-65 mm.

8. The LCD projection optical path structure according to any one of claims 1-6, characterized in that: The second polarizer has a length of 100-110 mm and a width of 60-65 mm.

9. The LCD projection optical path structure according to any one of claims 1-6, characterized in that: The front Fresnel lens has a length of 55.20-82.80 mm, a width of 32.80-49.20 mm, and a thickness of 1.20-1.80 mm.

10. The LCD projection optical path structure according to any one of claims 1-6, characterized in that: The length of the rear Fresnel lens is 52.00-78.00 mm, the width is 29.60-44.40 mm, and the thickness is 1.20-1.80 mm.

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