LCD projection light path

Abstract

An LCD projection light path comprises a light source, a collecting lens, a polarization beam splitter, a rear Fresnel lens, an LCD screen, a front Fresnel lens, a reflector and a projection lens which are sequentially arranged in the light advancing direction. Heat insulation glass is coaxially arranged between the rear Fresnel lens and the LCD screen; a radiator is arranged on the back surface of the polarization beam splitter; the polarization beam splitter splits incident light of the light source into P polarized light and S polarized light in a polarization state; the P polarized light is emitted to the radiator after penetrating through the polarization beam splitter, and the S polarized light is emitted to the rear Fresnel lens in the light advancing direction. According to the utility model, the defects in the prior art are overcome, and the light is converted into linearly polarized light before entering the heat insulation glass. After penetrating through the polarization beam splitter, other energy irradiates the radiator and is converted into heat to be taken away. Therefore, the linearly polarized light is incident on the heat-insulating glass, most of the light can penetrate through the heat-insulating glass and cannot be absorbed by the heat-insulating glass, and the service life of the heat-insulating glass is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of projection, in particular to an LCD projection light path. Background Art

[0002] LCD projector is a type of projector. LCD projector has the advantages of good color reproduction, high resolution, small size and light weight. It is also very convenient to carry. It is currently the mainstream product in the projector market.

[0003] In single LCD projection, reflective cups or aspherical lenses are usually used as devices to collect and shape the energy of LED light sources. The LED light source emits natural light, while the LCD screen is a polarized device. Half or more of the energy of the natural light emitted by the LED is absorbed by the heat-insulating glass in front of the LCD screen, and after passing through the heat-insulating glass, it becomes linearly polarized light and passes through the LCD screen. Therefore, the heat-insulating glass intercepts half or more of the energy of the LED, which will shorten the service life of the heat-insulating glass. Utility Model Content

[0004] In view of the deficiencies of the prior art, the utility model provides an LCD projection optical path, which overcomes the deficiencies of the prior art and has a reasonable design, and will not cause the problem of excessively high temperature of the insulating glass, thereby effectively improving the service life of the insulating glass.

[0005] In order to achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] An LCD projection optical path comprises a light source, a condenser, a polarization beam splitter, a rear Fresnel lens, an LCD screen, a front Fresnel lens, a reflector and a projection lens which are sequentially arranged along the direction of light travel; the feature is that a heat-insulating glass is coaxially arranged between the rear Fresnel lens and the LCD screen;

[0007] A heat sink is arranged on the back of the polarization beam splitter, and the polarization beam splitter splits the incident light from the light source into P polarized light and S polarized light in polarization states; the P polarized light is emitted onto the heat sink after passing through the polarization beam splitter, and the S polarized light is emitted onto the rear Fresnel lens along the direction of light travel.

[0008] Preferably, one side of the front Fresnel lens is a plane mirror, and the other side is a convex lens with threads, and the plane mirror is opposite to the LCD screen.

[0009] Preferably, the surface of the heat-insulating glass is coated with a polarizing film and a brightness-enhancing film.

[0010] Preferably, the condenser is any one of a single lens, a combination of lenses, or a combination of a reflective cup and a lens.

[0011] Preferably, the reflector is a plane reflector, the optical axis of the front Fresnel lens forms an angle of 45° with the reflector, the optical axis of the projection lens forms an angle of 45° with the reflector, and the reflector reflects the light emitted from the front Fresnel lens by 90° and then injects it into the projection lens.

[0012] The utility model provides an LCD projection optical path. It has the following beneficial effects: by setting a polarization beam splitter, the incident light of the light source is divided into P polarized light and S polarized light in polarization states, and the energy carried by the P polarized light is absorbed by the heat sink after passing through the polarization beam splitter. The collimated S polarized light is incident on the heat insulating glass, and most of the light can pass through the heat insulating glass without being absorbed by the heat insulating glass, and only a small part of the light will be intercepted and absorbed by the heat insulating glass, so it will not cause the problem of excessive temperature of the heat insulating glass, thereby effectively improving the service life of the heat insulating glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings required for describing the prior art are briefly introduced below.

[0014] Figure 1 A schematic diagram of the structure of the utility model;

[0015] Description of the numbers in the figure:

[0016] 1. Light source; 2. Condenser; 3. Polarization beam splitter; 4. Rear Fresnel lens; 5. Heat-insulating glass; 6. LCD screen; 7. Front Fresnel lens; 8. Reflector; 9. Projection lens; 10. Radiator. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention.

[0018] Embodiment 1, as Figure 1 As shown, an LCD projection optical path comprises a light source 1, a condenser 2, a polarization beam splitter 3, a rear Fresnel lens 4, an LCD screen 6, a front Fresnel lens 7, a reflector 8 and a projection lens 9 which are sequentially arranged along the direction of light travel; the feature is that a heat-insulating glass 5 is coaxially arranged between the rear Fresnel lens 4 and the LCD screen 6;

[0019] A heat sink 10 is provided on the back of the polarization beam splitter 3, and the polarization beam splitter 3 splits the incident light of the light source 1 into P polarized light and S polarized light in polarization states; the P polarized light is emitted to the heat sink 10 after passing through the polarization beam splitter 3, and the S polarized light is emitted to the rear Fresnel lens 4 along the direction of light travel.

[0020] Working principle:

[0021] During operation, the light source 1 emits white natural light, which is pre-collimated by the condenser 2 and then incident on the polarization beam splitter 3. The polarization beam splitter 3 divides the incident light of the light source 1 into P polarized light and S polarized light in polarization states. The P polarized light passes through the polarization beam splitter 3 and then is emitted to the heat sink 10, so that the heat brought by the P polarized light can be absorbed by the heat sink 10; while the S polarized light is reflected by the polarization beam splitter 3, and the reflected S polarized light is emitted to the rear Fresnel lens 4 along the direction of light travel for collimation and collection, and then enters the heat-insulating glass 5 and is incident on the LCD screen 6. The light passing through the LCD screen 6 is collected by the front Fresnel lens 7 and then reflected by the reflector 8 to enter the projection lens 9, so that the image generated by the LCD screen 6 is magnified and projected through the projection lens 9.

[0022] In this embodiment, the incident light of the light source 1 is divided into P polarized light and S polarized light in polarization states by setting the polarization beam splitter 3, and the energy carried by the P polarized light is absorbed by the heat sink 10 after passing through the polarization beam splitter 3. The collimated S polarized light is incident on the heat insulating glass, and most of the light can pass through the heat insulating glass without being absorbed by the heat insulating glass, and only a small part of the light will be intercepted and absorbed by the heat insulating glass 5, so that the problem of over-high temperature of the heat insulating glass 5 will not be caused, thereby effectively improving the service life of the heat insulating glass 5.

[0023] Embodiment 2, as a further preferred solution of embodiment 1, one side of the front Fresnel lens 7 is a plane mirror, and the other side is a convex lens with threads, and the plane mirror is opposite to the LCD screen 6. Thus, the light beam output by the front Fresnel lens 7 can form a focusing effect.

[0024] Embodiment 3, as a further preferred solution of embodiment 1, a polarizing film and a brightness enhancing film are coated on the surface of the heat insulating glass 5. The polarizing film is provided to absorb stray light, and the brightness of light can be increased by providing the brightness enhancing film.

[0025] Embodiment 4, as a further preferred embodiment of embodiment 1, the condenser 2 is a single lens, a combination of lenses, or a combination of a reflector cup and a lens. Specifically, it is a single lens with a plano-convex structure, the convex surface is a free-form surface, and the plane faces the light source 1.

[0026] Embodiment 5, as a further preferred solution of Embodiment 1, the reflector 8 is a plane reflector, the optical axis of the front Fresnel lens 7 forms an angle of 45° with the reflector 8, the optical axis of the projection lens 9 forms an angle of 45° with the reflector 8, and the reflector 8 reflects the light emitted from the front Fresnel lens 7 by 90° and then enters the projection lens 9. The reflector 8 can change the direction of the light emitted from the front Fresnel lens 7, thereby making the optical path structure more compact, which is convenient for miniaturization of the LCD projector.

[0027] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An LCD projection optical path, comprising a light source (1), a condenser (2), a polarization beam splitter (3), a rear Fresnel lens (4), an LCD screen (6), a front Fresnel lens (7), a reflector (8) and a projection lens (9) arranged in sequence along the direction of light travel; characterized in that: A heat-insulating glass (5) is coaxially arranged between the rear Fresnel lens (4) and the LCD screen (6); A heat sink (10) is arranged on the back of the polarization beam splitter (3), and the polarization beam splitter (3) splits the incident light of the light source (1) into P-polarized light and S-polarized light in polarization states; the P-polarized light is emitted onto the heat sink (10) after passing through the polarization beam splitter (3), and the S-polarized light is emitted onto the rear Fresnel lens (4) along the direction of light travel.

2. The LCD projection optical path according to claim 1, characterized in that: One side of the front Fresnel lens (7) is a plane mirror, and the other side is a convex lens with threads, and the plane mirror is opposite to the LCD screen (6).

3. The LCD projection optical path according to claim 1, characterized in that: The surface of the heat-insulating glass (5) is coated with a polarizing film and a brightness-enhancing film.

4. The LCD projection optical path according to claim 1, characterized in that: The condenser (2) is any one of a single lens, a combination of lenses, or a combination of a reflective cup and a lens.

5. The LCD projection optical path according to claim 1, characterized in that: The reflector (8) is a plane reflector, the optical axis of the front Fresnel lens (7) forms an angle of 45° with the reflector (8), the optical axis of the projection lens (9) forms an angle of 45° with the reflector (8), and the reflector (8) reflects the light emitted from the front Fresnel lens (7) by 90° and then makes it incident on the projection lens (9).

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