Optical device for single LCD projection

Abstract

The utility model discloses a single LCD projection optical device which comprises a light source assembly, a front Fresnel lens, a polarized light brightness enhancement film, an LCD liquid crystal screen, a rear Fresnel lens, a reflector and a projection lens. According to the light path structure, the transmission type polarized light brightening film is used, after light emitted by the light source is subjected to polarized light brightening, P light penetrates through and irradiates the liquid crystal screen, most S light is reflected back to the Fresnel lens and the front-end optical system by the polarized light brightening film, the S light is depolarized after passing through all layers of materials of the Fresnel lens and the front-end optical system, and therefore the light path structure is formed. And after the light becomes full polarized light (P light and S light), the light is emitted out of the Fresnel lens and the front-end optical system again and is recycled, so that the lighting effect of the single-LCD projector can be greatly improved.

Description

Technical Field

[0001] The utility model relates to the field of projection equipment, and more specifically, to an optical device for single LCD projection. Background Art

[0002] The existing single LCD projector optical system uses an LED (Light Emitting Diode) light source, which is simply focused by a single condenser or reflector cup, and then illuminates the front Fresnel lens, and then illuminates the LCD screen. After the LCD screen displays the image, it is converged by the rear Fresnel lens, reflected by the reflector, and then projected on the screen through the lens.

[0003] Since the existing single LCD projector lighting part has a simple structure, most products do not have the P-light and S-light conversion function. Based on the characteristic that the LCD screen can only transmit P-light, the light efficiency is low, resulting in the defect of low brightness of the single LCD projector.

[0004] In recent years, the new technology solution is to add a quarter wave plate and a reflective polarizer between the Fresnel lens and the LCD screen. Although the reflective polarizer can transmit P light and reflect S light, and the reflected S light can also complete the polarization conversion after passing through the quarter wave plate, this part of the light will return to the LED as the original light and cannot be reflected back again. It can only be reflected multiple times in the form of diffuse reflection, forming stray light, which is eventually lost. Therefore, this method is also relatively inefficient. Utility Model Content

[0005] The utility model overcomes the shortcomings of the prior art and provides an optical device for single LCD projection, so as to solve the problem of low efficiency.

[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0007] An optical device for single LCD projection, comprising a light source assembly, a front Fresnel lens, a polarized brightness enhancement film, an LCD screen, a rear Fresnel lens, a reflector, and a projection lens;

[0008] The light source assembly comprises a light source, a front Fresnel lens is arranged behind the light source, a polarized brightness enhancement film is arranged behind the front Fresnel lens, an LCD screen is arranged behind the polarized brightness enhancement film, and a rear Fresnel lens is arranged behind the LCD screen;

[0009] The absorption axis of the polarized brightness enhancement film is parallel to the upper polarized film of the LCD screen;

[0010] A reflector is arranged behind the rear Fresnel lens, the reflector is arranged tilted, and a projection lens is arranged behind the reflector.

[0011] The conversion process is as follows: the circularly polarized light is emitted by the LED light source, which passes through the polarizing brightening film, and the P light is transmitted to the LCD screen, but most of the S light will be reflected back to the Fresnel lens and the front-end optical system by the polarizing brightening film. After passing through the Fresnel lens and various layers of materials in the front-end optical system, the S light is depolarized and becomes fully polarized light (P light + S light), and then re-emits the Fresnel lens and the front-end optical system to be recycled and utilized, which can greatly improve the light efficiency of the single LCD projector.

[0012] A further technical solution is that the polarized brightness enhancement film is attached to the LCD screen.

[0013] A further technical solution is that the light source assembly further includes a focusing assembly, and the focusing assembly is arranged between the light source and the front Fresnel lens.

[0014] The focusing component can be a focusing mirror or a reflective cup, and its effect is to focus the light emitted by the LED light source and then pass it through the front Fresnel lens.

[0015] A further technical solution is that the optical device of the single LCD projection further includes heat-insulating glass, and the heat-insulating glass is arranged in front of the LCD screen.

[0016] The heat-insulating glass can block heat and infrared rays, and can protect the LCD screen and other components in the device.

[0017] A further technical solution is that the polarized brightness enhancement film is attached to the heat-insulating glass.

[0018] A further technical solution is that the reflector is a plane reflector, the optical axis of the front Fresnel lens forms an angle of 45° with the plane reflector, and the optical axis of the projection lens forms an angle of 45° with the plane reflector.

[0019] The plane reflector reflects the light emitted from the front Fresnel lens by 90° and then injects the light into the projection lens, and then emits the light outward to form a projection.

[0020] Compared with the prior art, the utility model has at least the following beneficial effects: a transmissive polarized brightness enhancement film is used in the optical path structure of the utility model, and after the light emitted by the light source is polarized and brightened, the P light is transmitted and irradiated onto the liquid crystal screen, and most of the S light is reflected back to the Fresnel lens and the front-end optical system by the polarized brightness enhancement film, and after passing through the Fresnel lens and various layers of materials of the front-end optical system, the S light is depolarized and becomes fully polarized light (P light + S light) and then re-emits the Fresnel lens and the front-end optical system to be recycled and utilized, which can greatly improve the light efficiency of the single LCD projector. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the utility model;

[0022] Figure 2 Schematic diagram of the working principle of polarized brightness enhancement film.

[0023] In the figure, 1-light source assembly, 11-light source, 12-focusing assembly, 2-front Fresnel lens, 3-polarized light enhancement film, 4-LCD screen, 5-rear Fresnel lens, 6-reflector, 7-projection lens, 8-heat-insulating glass. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0025] An optical device for single LCD projection, see Figure 1 , including a light source assembly 1, a front Fresnel lens 2, a polarized brightness enhancement film 3, an LCD screen 4, a rear Fresnel lens 5, a reflector 6, a projection lens 7, and a heat-insulating glass 8;

[0026] The light source assembly 1 comprises a light source 11 and a focusing assembly 12 . A front Fresnel lens 2 is disposed behind the light source 11 , and the focusing assembly 12 is disposed between the light source 11 and the front Fresnel lens 2 .

[0027] In this embodiment, the light source 11 is an LED light source.

[0028] The focusing component 12 may be a focusing mirror or a reflective cup, and its effect is to focus the light emitted by the LED light source and then pass through the front Fresnel lens 2. In this embodiment, the focusing component 12 is a reflective cup.

[0029] A polarized brightness enhancement film 3 is arranged behind the front Fresnel lens 2 , an LCD screen 4 is arranged behind the polarized brightness enhancement film 3 , a rear Fresnel lens 5 is arranged behind the LCD screen 4 , and the heat-insulating glass 8 is arranged in front of the LCD screen 4 .

[0030] The polarized brightness enhancement film 3 can be attached to the LCD screen 4, or attached to the heat-insulating glass 8, or can be separately arranged between the front Fresnel lens 2 and the LCD screen 4. In this embodiment, the polarized brightness enhancement film 3 is separately arranged between the front Fresnel lens 2 and the LCD screen 4.

[0031] The heat-insulating glass 8 can block heat and infrared rays, and can protect the LCD screen 4 and other components in the device.

[0032] The absorption axis of the polarizing brightness enhancement film 3 is parallel to the upper polarizing film of the LCD screen 4;

[0033] A reflector 6 is disposed behind the rear Fresnel lens 5 . The reflector 6 is tilted. A projection lens 7 is disposed behind the reflector 6 .

[0034] The reflector 6 is a plane reflector 6 , the optical axis of the front Fresnel lens 2 forms an angle of 45° with the plane reflector 6 , and the optical axis of the projection lens 7 forms an angle of 45° with the plane reflector 6 .

[0035] When the single LCD projection system is in operation, the LED light source emits light, which is focused by the reflective cup. The reflectivity of the reflective cup can reach ≥90%. After focusing, the light passes through the front Fresnel mirror. The light transmittance of the front Fresnel mirror is ≥90%. The scattered light is modulated into parallel light, which passes through the heat-insulating glass 8 and the polarized light enhancement film 3. When passing through the polarized light enhancement film 3, Figure 2 , P light passes through and illuminates the LCD screen, but most of the S light will be reflected back to the front Fresnel lens 2 and the front optical system by the polarizing brightening film. After passing through the front Fresnel lens 2 and various layers of materials in the front optical system, the S light is depolarized and becomes fully polarized light (P light + S light) and then re-emits the front Fresnel lens 2 and the front optical system to be recycled, which can greatly improve the light efficiency of the single LCD projector.

[0036] After passing through the polarized brightness enhancement film 3, the light is displayed on the LCD screen 4, and then shaped by the rear Fresnel mirror. The light transmittance of the rear Fresnel mirror is ≥ 90%. In order to reduce the volume, it must be reflected and folded by the reflector 6, and finally projected by the projection lens 7 to form an image. The final processed image can achieve a higher brightness.

[0037] Although the utility model is described herein with reference to the illustrative embodiments of the utility model, it should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in the present application. More specifically, within the scope disclosed in the present application, multiple variations and improvements can be made to the components and / or layout of the subject combination layout. In addition to the variations and improvements made to the components and / or layout, other uses will also be obvious to those skilled in the art.

Claims

1. An optical device for single LCD projection, characterized in that: Including light source assembly, front Fresnel lens, polarized brightness enhancement film, LCD screen, rear Fresnel lens, reflector, and projection lens; The light source assembly comprises a light source, a front Fresnel lens is arranged behind the light source, a polarized brightness enhancement film is arranged behind the front Fresnel lens, an LCD screen is arranged behind the polarized brightness enhancement film, and a rear Fresnel lens is arranged behind the LCD screen; The absorption axis of the polarized brightness enhancement film is parallel to the upper polarized film of the LCD screen; A reflector is arranged behind the rear Fresnel lens, the reflector is arranged tilted, and a projection lens is arranged behind the reflector.

2. An optical device for single LCD projection as claimed in claim 1, characterized in that: The polarized brightness enhancement film is attached to the LCD screen.

3. An optical device for single LCD projection as claimed in claim 1, characterized in that: The light source assembly comprises a focusing assembly, and the focusing assembly is arranged between the light source and the front Fresnel lens.

4. An optical device for single LCD projection as claimed in claim 1, characterized in that: The invention comprises heat-insulating glass, wherein the heat-insulating glass is arranged in front of the LCD screen.

5. An optical device for single LCD projection as claimed in claim 4, characterized in that: The polarized brightness enhancement film is attached to the heat-insulating glass.

6. The optical device for single LCD projection as claimed in claim 1, characterized in that: The reflector is a plane reflector, the optical axis of the front Fresnel lens forms an angle of 45° with the plane reflector, and the optical axis of the projection lens forms an angle of 45° with the plane reflector.

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