LCD projection optical system with uniform chromaticity

Abstract

The utility model relates to an LCD projection optical system with uniform chromaticity. The LCD projection optical system comprises a light emitting unit, a rear Fresnel lens, an LCD screen, a front Fresnel lens, a reflector and a projection lens which are sequentially arranged along the light propagation direction, the light emitting unit comprises a light emitting source and a light funnel, a reflecting film layer is plated in the light funnel, and the average reflectivity of the reflecting film layer to illumination light rays with the wavelength range of 400-700 mm is larger than or equal to 80%; and when the wavelength of the illumination light is in a range of 400-500mm, the reflectivity of the reflecting film layer is gradually reduced along with the increase of the wavelength of the illumination light. The reflective film layer is arranged in the light funnel, and the reflective film layer has the characteristics, so that the reflectivity of the light funnel to low-band blue light is greater than that of high-band yellow light, the yellow light entering the edge of the LCD screen after being emitted from the light funnel is less, the color temperature is increased, the problem that a projection edge picture is yellowish can be solved, and the brightness of the LCD screen is improved. Therefore, the chromaticity of the emitted projection light is uniform, and the user experience can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of projectors, in particular to an LCD projection optical system with uniform chromaticity. Background Art

[0002] A single-chip LCD projector uses a high-power light source to emit light to an LCD screen, and then projects the light that passes through the LCD screen onto a screen through a projection lens to form an image.

[0003] As projectors are increasingly used in daily life, LCD projectors are becoming more intelligent and brighter, and are becoming more and more popular among consumers. Currently, LCD projectors generally have poor color uniformity, which is often manifested as yellowing at the edges of the projected image and whiteness in the center, which seriously affects the user experience. Utility Model Content

[0004] Based on this, the purpose of the utility model is to overcome the deficiencies of the prior art and provide an LCD projection optical system with uniform chromaticity.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A chromaticity uniform LCD projection optical system, comprising:

[0007] A light emitting unit, a rear Fresnel lens, an LCD screen, a front Fresnel lens, a reflector and a projection lens are sequentially arranged along the light propagation direction;

[0008] The reflector is arranged at an angle of 45° so as to reflect the light emitted from the LCD screen by 90° and then enter the projection lens;

[0009] The light emitting unit comprises a light source and a light funnel, wherein the light source is arranged at a light inlet of the light funnel, and the light source emits illumination light to the light funnel, and the rear Fresnel lens is arranged at a light outlet of the light funnel, and the size of the light inlet is smaller than the size of the light outlet;

[0010] The light funnel is plated with a reflective film layer, and the average reflectivity of the reflective film layer to the illumination light with a wavelength range of 400-700mm is ≥80%; when the wavelength of the illumination light is in the range of 400-500mm, the reflectivity of the reflective film layer gradually decreases as the wavelength of the illumination light increases.

[0011] As an implementation manner, the area of ​​the reflective film layer is at least 99% of the area of ​​the inner surface of the light funnel.

[0012] As an implementation manner, the reflective film layer is a magnesium fluoride reflective film or a titanium dioxide reflective film.

[0013] As an implementation manner, the light entrance has a length of 17-21 mm and a width of 12-16 mm, the light exit has a length of 85-105 mm and a width of 60-80 mm; and the distance between the light entrance and the light exit is 66-100 mm.

[0014] As an implementation manner, the light source is an LED, and its light power is 110-145W.

[0015] As an implementation manner, a heat insulating sheet is provided between the rear Fresnel lens and the LCD screen.

[0016] As an embodiment, a brightness enhancement film is provided on the surface of the thermal insulation sheet.

[0017] As an implementation manner, a polarizing film is further provided on the surface of the heat insulation sheet.

[0018] As an embodiment, the thermal insulation sheet has a length of 109-163 mm, a width of 68-102 mm, and a thickness of 1.0-1.2 mm.

[0019] As an implementation manner, the focal length of the rear Fresnel lens is 90-130 mm, the size of the LCD screen is 5.2-6.2 inches, and the focal length of the front Fresnel lens is 142-214 mm.

[0020] The present application sets a reflective film layer in the light funnel, and the characteristics of the reflective film layer are as described above, so that the reflectivity of the light funnel to low-band blue light is greater than the reflectivity of high-band yellow light. Therefore, after being emitted from the light funnel, the yellow light entering the edge of the LCD screen is less, and the color temperature becomes higher, thereby solving the problem of yellowing of the projection edge image, thereby making the chromaticity of the emitted projection light uniform, and improving the user experience.

[0021] In order to better understand and implement the present invention, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a high-definition projector with high edge light utilization in this application;

[0023] Figure 2 This is a schematic diagram of the three-dimensional structure of the light funnel of the present application;

[0024] Figure 3 This is a schematic diagram of the side structure of the light funnel of the present application;

[0025] Figure 4 This is a schematic diagram of the structure of the heat insulation sheet of this application;

[0026] Description of reference numerals:

[0027] 1. Light output unit; 11. Light source; 12. Light funnel; 121. Light inlet; 122. Light outlet; 2. Rear Fresnel lens; 3. Heat shield; 4. LCD screen; 5. Front Fresnel lens; 6. Reflector; 7. Projection lens. DETAILED DESCRIPTION

[0028] To further illustrate each embodiment, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which 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 contents, ordinary technicians in the field should be able to understand other possible implementation methods and advantages of the present invention.

[0029] In the description of the present invention, it needs to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "left", "right", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0030] See also Figures 1 to 4 This embodiment provides an LCD projection optical system with uniform chromaticity, comprising a light emitting unit 1, a rear Fresnel lens 2, an LCD screen 4, a front Fresnel lens 5, a reflector 6 and a projection lens 7 arranged in sequence along the light propagation direction. The reflector 6 is arranged at a 45° inclination to reflect the light emitted from the LCD screen 4 by 90° and then enter the projection lens 7.

[0031] Among them, the light output unit 1 includes a light source 11 and a light funnel 12, the light source 11 can emit illumination light to the light funnel, the light funnel 12 has a light inlet 121 and a light outlet 122 opposite to each other along the optical axis, the size of the light inlet 121 is smaller than the size of the light outlet 122, the light inlet 121 of the light funnel 12 is rectangular, having a pair of short sides and a pair of long sides, similarly, the light outlet 122 of the light funnel 12 is also rectangular, also having a pair of short sides and a pair of long sides, the short side of the light inlet 121 corresponds to the short side of the light outlet 122, and the long side of the light inlet 121 corresponds to the long side of the light outlet 122, so that the focusing cavity inside the light funnel 12 has a trapezoidal structure; the light source is arranged at the light inlet of the light funnel, and the rear Fresnel lens is arranged at the light outlet of the light funnel.

[0032] The light funnel 12 is coated with a reflective film layer to reflect and focus the incident light so that the light is roughly uniformly emitted in parallel. The average reflectivity of the reflective film layer to the illumination light with a wavelength range of 400-700 mm is ≥ 80%; when the wavelength of the illumination light is within the range of 400-500 mm, the reflectivity of the reflective film layer gradually decreases as the wavelength of the illumination light increases.

[0033] By providing a reflective film layer in the light funnel 12, the characteristics of the reflective film layer are as described above, so that the reflectivity of the light funnel to low-band blue light can be greater than the reflectivity of high-band yellow light. Therefore, the yellow light entering the edge of the LCD screen after being emitted from the light funnel is less, and the color temperature becomes higher, thereby solving the problem of yellowing of the projection edge image, thereby making the chromaticity of the emitted projection light uniform, which can improve the user experience.

[0034] Preferably, the area of ​​the reflective film layer is at least 99% of the area of ​​the inner surface of the light funnel, which can ensure that the chromaticity of the projection light is more uniform.

[0035] Preferably, the reflective film layer is a magnesium fluoride reflective film or a titanium dioxide reflective film.

[0036] Preferably, the length L1 of the light inlet 121 is 17-21 mm, and the width W1 is 12-16 mm; the length L2 of the light outlet 122 is 85-105 mm, and the width W2 is 60-80 mm; the distance D3 between the light inlet 121 and the light outlet 122 is 66-100 mm, and the size of the light funnel 12 is reasonably designed, so that the light coming out of the light funnel 12 is uniform.

[0037] Preferably, the light source is an LED, the light emitting power is 110-145W, the light emitted is white light, the light emitting brightness is sufficient and the angle is reasonable.

[0038] In order to reduce the luminous heat and reduce the risk of device damage, preferably, a heat insulation sheet 3 is provided between the rear Fresnel lens and the LCD screen. In this embodiment, the heat insulation sheet 3 is made of glass, such as Figure 4 As shown, the length L4 of the heat insulation sheet 3 is 109-163mm, the width W4 is 68-102mm, and the thickness is 1.0-1.2mm. Preferably, a brightness enhancement film is provided on the surface of the heat insulation sheet 3 to increase the brightness of light, and the surface of the brightness enhancement film is a 90° incremental prism structure. Furthermore, a polarizing film is also provided on the surface of the heat insulation sheet 3 to filter polarized light and block stray light.

[0039] The focal length of the rear Fresnel lens is 90-130 mm, the size of the LCD screen is 5.2-6.2 inches, and the focal length of the front Fresnel lens is 142-214 mm. The projection optical system uses a 5.2-6.2 inch LCD screen 4 to form a projection image, and is matched with a rear Fresnel lens 2 and a front Fresnel lens 5 of appropriate focal length, so that the design and arrangement of each optical element are very reasonable. Such a setting can make full use of edge light, improve the utilization rate of light and the uniformity of illumination.

[0040] The LCD projection optical system of the present application, its light is emitted from the LED and incident on the light funnel 12 for multiple reflections to achieve a uniform light effect, and the light is then collimated by the rear Fresnel mirror, and the collimated near-parallel light illuminates the LCD screen 4, and then the light beam is further reduced by focusing through the front Fresnel mirror, and finally the light is projected onto the screen through the projection lens 7 to form an image.

[0041] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model manual self-centering vise. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model.

Claims

1. A chromaticity uniform LCD projection optical system, characterized in that: include: A light emitting unit, a rear Fresnel lens, an LCD screen, a front Fresnel lens, a reflector and a projection lens are sequentially arranged along the light propagation direction; The reflector is arranged at an angle of 45° to reflect the light emitted from the LCD screen by 90° and then enter the projection lens; The light emitting unit comprises a light source and a light funnel, wherein the light source is arranged at a light inlet of the light funnel, and the light source emits illumination light to the light funnel, and the rear Fresnel lens is arranged at a light outlet of the light funnel, and the size of the light inlet is smaller than the size of the light outlet; The light funnel is plated with a reflective film layer, and the average reflectivity of the reflective film layer to the illumination light with a wavelength range of 400-700mm is ≥80%; when the wavelength of the illumination light is in the range of 400-500mm, the reflectivity of the reflective film layer gradually decreases as the wavelength of the illumination light increases.

2. The LCD projection optical system with uniform chromaticity according to claim 1, characterized in that: The area of ​​the reflective film layer is at least 99% of the area of ​​the inner surface of the light funnel.

3. The LCD projection optical system with uniform chromaticity according to claim 1, characterized in that: The reflective film layer is a magnesium fluoride reflective film or a titanium dioxide reflective film.

4. The LCD projection optical system with uniform chromaticity according to claim 1, characterized in that: The length of the light entrance is 17-21 mm, and the width is 12-16 mm; the length of the light exit is 85-105 mm, and the width is 60-80 mm; the distance between the light entrance and the light exit is 66-100 mm.

5. The LCD projection optical system with uniform chromaticity according to claim 4, characterized in that: The light source is an LED, and its light power is 110-145W.

6. The LCD projection optical system with uniform chromaticity according to claim 1, characterized in that: A heat insulation sheet is arranged between the rear Fresnel lens and the LCD screen.

7. The LCD projection optical system with uniform chromaticity according to claim 6, characterized in that: A brightness enhancement film is arranged on the surface of the heat insulation sheet.

8. The LCD projection optical system with uniform chromaticity according to claim 7, characterized in that: A polarizing film is also provided on the surface of the heat insulation sheet.

9. The LCD projection optical system with uniform chromaticity according to claim 6, characterized in that: The heat insulation sheet has a length of 109-163 mm, a width of 68-102 mm, and a thickness of 1.0-1.2 mm.

10. The LCD projection optical system with uniform chromaticity according to any one of claims 1 to 9, characterized in that: The focal length of the rear Fresnel lens is 90-130 mm, the size of the LCD screen is 5.2-6.2 inches, and the focal length of the front Fresnel lens is 142-214 mm.

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