Single-chip LCD projector

Abstract

The utility model discloses a single-chip LCD projector. The single-chip LCD projector comprises an illumination system and a projection imaging system, the lighting system comprises an LED lamp panel, a reflection cup, a first Fresnel lens and heat insulation glass, wherein the reflection cup, the first Fresnel lens and the heat insulation glass are sequentially arranged in the propagation direction of emergent light of the LED lamp panel. The length of the effective light-emitting face of the LED lamp panel is not smaller than 9 mm and not larger than 11.5 mm, the width of the effective light-emitting face of the LED lamp panel is not smaller than 6 mm and not larger than 9 mm, the length of an incidence opening of the reflection cup is not smaller than 10 mm and not larger than 12.5 mm, the width of the incidence opening is not smaller than 7 mm and not larger than 10 mm, the length of an exit opening is not smaller than 82 mm and not larger than 84 mm, the width of the exit opening is not smaller than 45 mm and not larger than 48 mm, the vertical height of the exit opening is not smaller than 44 mm and not larger than 46 mm, and the length of the first Fresnel lens is not smaller than 85 mm and not larger than 90 mm. The width is not smaller than 49 mm and not larger than 53 mm, the thickness is not smaller than 1.6 mm and not larger than 2.2 mm, and the focal length is not smaller than 55 mm and not larger than 65 mm; the projection imaging system comprises an LCD liquid crystal light valve and a projection lens, and the LCD liquid crystal light valve is arranged on the side, back to the first Fresnel lens, of the heat insulation glass.

Description

Technical Field

[0001] The present application relates to the technical field of projectors, and in particular to a single-chip LCD projector. Background Art

[0002] In the related art, a single-chip LCD projector uses a high-power light source to emit light to an LCD panel, and then projects the light passing through the LCD panel onto a screen through a projection lens to form an image.

[0003] With more and more applications in daily life, the miniaturization of single-chip LCD projectors has also become a development trend. However, in the process of miniaturization, single-chip LCD projectors are prone to many problems such as poor light utilization and uneven brightness due to the unreasonable matching of various optical components. Utility Model Content

[0004] The embodiment of the present application provides a single-chip LCD projector. The technical solution of the present application can achieve a simple structure, high light utilization and brightness uniformity, meet the requirements of miniaturization and large screen of the single-chip LCD projector, and at the same time achieve 1080P high-definition imaging rate.

[0005] The embodiment of the present application provides a single-chip LCD projector, including an illumination system and a projection imaging system;

[0006] The lighting system includes an LED light board for providing lighting light, a reflective cup, a first Fresnel lens and a heat-insulating glass which are coaxially arranged in sequence along the propagation direction of the light emitted by the LED light board;

[0007] Among them, the length of the effective light-emitting surface of the LED light board is not less than 9mm and not more than 11.5mm, the width is not less than 6mm and not more than 9mm, the length of the incident port of the reflector cup is not less than 10mm and not more than 12.5mm, the width is not less than 7mm and not more than 10mm, the length of the outlet is not less than 82mm and not more than 84mm, the width is not less than 45mm and not more than 48mm, the vertical height is not less than 44mm and not more than 46mm, the length of the first Fresnel lens is not less than 85mm and not more than 90mm, the width is not less than 49mm and not more than 53mm, the thickness is not less than 1.6mm and not more than 2.2mm, and the focal length is not less than 55mm and not more than 65mm;

[0008] The projection imaging system comprises an LCD liquid crystal light valve and a projection lens. The LCD liquid crystal light valve is arranged on a side of the heat-insulating glass facing away from the first Fresnel lens, and the light emitted by the LCD liquid crystal light valve is directed toward the projection lens.

[0009] In a possible implementation, the first Fresnel lens is laminated to the exit of the reflective cup.

[0010] In a possible implementation, the heat-insulating glass includes a glass substrate and optical film layers disposed on two opposite surfaces of the glass substrate;

[0011] The optical film layer on the side of the glass substrate close to the first Fresnel lens is a reflective polarizing film, and the optical film layer on the side away from the first Fresnel lens is an absorbing polarizing film.

[0012] In a possible implementation, the length of the insulating glass is not less than 85 mm and not more than 90 mm, the width is not less than 49 mm and not more than 53 mm, and the thickness is not less than 0.8 mm and not more than 1.2 mm.

[0013] In a possible implementation, the center distance between the first Fresnel lens and the heat-insulating glass is not less than 2 mm and not more than 4 mm; and / or

[0014] The center distance between the insulating glass and the LCD liquid crystal light valve is not less than 5mm and not more than 10mm.

[0015] In a possible implementation, the projection imaging system further includes a second Fresnel lens and a reflector;

[0016] The reflector is tilted at 45° to reflect the light emitted from the LCD light valve by 90° and then enter the projection lens.

[0017] In a possible implementation, the center thickness of the second Fresnel lens is 2.0 mm, the surface of the second Fresnel lens close to the LCD liquid crystal light valve is substantially a plane, and the surface of the second Fresnel lens away from the LCD liquid crystal light valve is a Fresnel surface;

[0018] Among them, the surface shape of the Fresnel surface is an even-order aspheric surface, the radius of curvature is 46mm, and the conic coefficient conic is -1.03.

[0019] In a possible implementation, the length of the second Fresnel lens is not less than 85 mm and not more than 90 mm, and the width is not less than 49 mm and not more than 53 mm.

[0020] In a possible implementation, the projection lens includes a first lens, a second lens, and a third lens coaxially arranged in sequence along the direction of the outgoing light of the lens;

[0021] The first lens and the third lens both have positive refractive power, and the second lens has negative refractive power;

[0022] Wherein, the refractive index Nd1 of the first lens satisfies: 1.65≤Nd1≤1.7, and the Abbe number Vd1 satisfies: 50≤Vd1≤60;

[0023] The refractive index Nd2 of the second lens satisfies: 1.65≤Nd2≤1.7, and the Abbe number Vd2 satisfies: 25≤Vd235;

[0024] The refractive index Nd3 of the third lens satisfies: 1.60≤Nd3≤1.67, and the Abbe number Vd3 satisfies: 45≤Vd3≤55.

[0025] In a possible implementation, a curvature radius R811 of an end surface of the first lens on a side away from the second lens satisfies: 40 mm ≤ R811 ≤ 50 mm, and a curvature radius R812 of an end surface of the first lens on a side close to the second lens satisfies: -200 mm ≤ R812 ≤ -100 mm;

[0026] The curvature radius R821 of the end surface of the second lens close to the first lens satisfies: -100mm≤R821≤-50mm, and the curvature radius R822 of the end surface of the second lens away from the first lens satisfies: 40mm≤R822≤55mm;

[0027] A curvature radius R831 of an end surface of the third lens close to the second lens satisfies: -1000mm≤R831≤-500mm, and a curvature radius R832 of an end surface of the third lens away from the second lens satisfies: -100mm≤R832≤-50mm.

[0028] A single-chip LCD projector based on an embodiment of the present application includes an illumination system and a projection imaging system. The illumination system includes an LED light board, a reflective cup, a first Fresnel lens, and heat-insulating glass. The illumination system reflects the light emitted by the LED light board multiple times through the reflective cup, thereby reducing the divergence range of the light. The first Fresnel lens is then used to collimate the light to form small-angle light with good brightness uniformity. By reasonably arranging the sizes of the LED light board, the reflective cup, the first Fresnel lens, and the heat-insulating glass, as well as the distances therebetween, the light emitted by the illumination system passes through the projection imaging system as much as possible to become effective light, thereby improving the light efficiency of the optical system and meeting the requirements of miniaturization and large screen of the single-chip LCD projector. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0030] Figure 1 A schematic diagram of a single-chip LCD projector according to an embodiment of the present application;

[0031] Figure 2A schematic diagram of a projection lens according to an embodiment of the present application;

[0032] Figure 3 This is a diagram of the light direction of a single-chip LCD projector;

[0033] Figure 4 It is a distortion curve corresponding to the projection imaging system according to an embodiment of the utility model.

[0034] Description of Figure Numbers:

[0035] 10. LED light board; 20. Reflector cup; 30. First Fresnel lens; 40. Heat-insulating glass; 50. LCD liquid crystal light valve; 60. Second Fresnel lens; 70. Reflector; 80. Projection lens; 81. First lens; 82. Second lens; 83. Third lens.

[0036] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present application clearer, the following part will further describe the embodiments of the present application in detail in conjunction with the accompanying drawings.

[0038] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0039] In the description of the present application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0041] In the related art, a single-chip LCD projector uses a high-power light source to emit light to an LCD panel, and then projects the light passing through the LCD panel onto a screen through a projection lens to form an image.

[0042] With more and more applications in daily life, the miniaturization of single-chip LCD projectors has also become a development trend. However, in the process of miniaturization, single-chip LCD projectors are prone to many problems such as poor light utilization and uneven brightness due to the unreasonable matching of various optical components.

[0043] To improve the uniformity and efficiency of light transmission, please refer to Figures 1 to 3 , an embodiment of the present application proposes a single-chip LCD projector, including an illumination system and a projection imaging system.

[0044] The lighting system includes an LED light board 10 , a reflective cup 20 , a first Fresnel lens 30 and a heat-insulating glass 40 .

[0045] The LED light board 10 is used to provide lighting light, wherein the length of the effective light-emitting surface of the LED light board 10 is not less than 9 mm and not more than 11.5 mm, the width is not less than 6 mm and not more than 9 mm, the length of the first Fresnel lens 30 is not less than 85 mm and not more than 90 mm, the width is not less than 49 mm and not more than 53 mm, the thickness is not less than 1.6 mm and not more than 2.2 mm, and the focal length is not less than 55 mm and not more than 65 mm. In some specific embodiments, the size of the effective light-emitting surface of the LED light board 10 is 10.5 mm*8.0 mm. The size of the substrate of the LED light board 10 is 40 mm*30 mm, and the driving power consumption is 40 W. Of course, in some other embodiments, the size of the substrate and the driving power consumption of the LED light board 10 can be set to other parameters. It can be understood that the size of the substrate of the LED light board 10 can be determined by heat dissipation design based on the driving power consumption of the LED.

[0046] Along the propagation direction of the light emitted by the LED lamp board 10, the reflective cup 20, the first Fresnel lens 30 and the heat-insulating glass 40 are coaxially arranged in sequence.

[0047] The reflective cup 20 is used to reflect and focus light, and has an incident port and an outlet relative to each other. The size of the incident port is smaller than the outlet, so that the focusing cavity inside the reflective cup 20 has a trapezoidal structure. In addition, the inner wall surface of the reflective cup 20 can be provided with a reflective layer for reflecting light, so as to reflect and focus the incident light, so that the light can be roughly uniformly emitted in parallel.

[0048] The length of the incident port of the reflective cup 20 is not less than 10 mm and not more than 12.5 mm, the width is not less than 7 mm and not more than 10 mm, the length of the outlet is not less than 82 mm and not more than 84 mm, the width is not less than 45 mm and not more than 48 mm, and the vertical height is not less than 44 mm and not more than 46 mm. In some structural forms, the size of the incident port of the reflective cup 20 is 12 mm*9.5 mm, the size of the outlet is 83.5 mm*47.5 mm, and the vertical height is 45 mm.

[0049] It should be noted that the above-mentioned reflective layer can be a reflective coating evenly coated on the inner wall surface of the reflective cup 20 to form a reflective coating; it can also be a reflective film attached to the inner wall surface of the reflective cup 20; reflective materials (such as aluminum, silver, silicon dioxide or material) can also be deposited on the inner wall surface of the reflective cup 20 through evaporation or magnetron sputtering or physical vapor deposition or chemical vapor deposition and other coating technologies to form a reflective layer on the cavity wall of the focusing cavity.

[0050] One side of the first Fresnel lens 30 is substantially flat, and the other side is a Fresnel surface having a plurality of concentric circular convex structures, so that the output light beam can form a focusing effect. It is understandable that in the production process and manufacturing process, it is impossible to produce a 100% flat surface on the surface of the second Fresnel lens 60. In this application, substantially flat means forming a surface close to a flat surface within the range allowed by the process error.

[0051] In the embodiment of the present application, the first Fresnel lens 30 can be made of polymethyl methacrylate (PMMA). Of course, in some other embodiments, the first Fresnel lens 30 can also be made of polycarbonate (PC), etc. Here, the present application does not limit the specific material of the first Fresnel lens 30. Among them, the size of the first Fresnel lens 30 in the embodiment of the present application is 89mm*52mm, the thickness is 2mm, and the focal length is 60mm.

[0052] The first Fresnel lens 30 is attached to the exit of the reflective cup 20. In this way, the light reflected by the reflective cup 20 can be collimated by the first Fresnel lens 30, thereby improving the utilization rate of the light source, making the light more concentrated and focused, thereby improving the lighting or projection effect.

[0053] The heat-insulating glass 40 includes a glass substrate and optical film layers arranged on two opposite surfaces of the glass substrate, wherein the optical film layer on the side of the glass substrate close to the first Fresnel lens 30 is a reflective polarizing film (DBEF), and the optical film layer on the side away from the first Fresnel lens 30 is an absorptive polarizing film (POL).

[0054] It should be noted that the light emitted by the LED light board 10 is natural light, that is, non-polarized light. The LCD liquid crystal light valve 50 usually requires light of a specific polarization state to pass through to realize the projection of the image. Assume that the LCD liquid crystal light valve 50 requires horizontal linear polarized light. The light emitted by the LED light board 10 will have 50% of the light energy, that is, vertical linear polarized light, and this part of the light is useless for the LCD liquid crystal light valve 50. In order to avoid this part of the light energy being absorbed by the LCD liquid crystal light valve 50, causing its temperature to rise and its life to be reduced, and even high-temperature damage may occur. The reflective polarizing film (DBEF) used in this application can reflect this part of the light energy, and the horizontally polarized light required by the LCD liquid crystal light valve 50 will pass through the diaphragm to illuminate it.

[0055] It is further explained that the reflectivity of the reflective polarizing film (DBEF) to vertical linear polarized light cannot reach 100%, so a small amount of vertical polarized light will still pass through the reflective polarizing film (DBEF). In the present application, the transmission axis of the absorbing polarizing film (POL) and the transmission axis of the reflecting polarizing film are set in the same direction, so that the absorbing polarizing film (POL) will absorb this part of the vertical linear polarized light that passes through, thereby improving the polarization degree of the illumination light beam, and further improving the display contrast of the LCD liquid crystal light valve 50.

[0056] The insulating glass 40 has a length of not less than 85 mm and not more than 90 mm, a width of not less than 49 mm and not more than 53 mm, and a thickness of not less than 0.8 mm and not more than 1.2 mm. In some specific embodiments, the size of the insulating glass 40 is 89 mm*52 mm, and the thickness of the insulating glass 40 is 1 mm, that is, the total thickness of the glass substrate and the optical film layer is 1 mm.

[0057] It is understandable that, considering the strength of the glass substrate, the thickness of the glass substrate cannot be too small, so the thickness specification of the glass substrate is generally selected to be 0.7 mm, and the thickness specification of the two layers of optical film layers is generally 0.1 mm to 0.15 mm, so the total thickness of the insulating glass 40 is not less than 0.8 mm, and in some embodiments, the glass substrate can also be of other thickness specifications. Of course, it is understandable that if the thickness of the glass substrate is too large, it will also increase the cost and occupy space. The thickness specification of the glass substrate in the embodiment of the present application is not greater than 1.1 mm, so the total thickness of the insulating glass 40 is not greater than 1.2 mm.

[0058] Based on the single-chip LCD projector of the embodiment of the present application, the lighting system includes an LED light board 10, a reflective cup 20, a first Fresnel lens 30 and an insulating glass 40. The lighting system reflects the light emitted by the LED light board 10 multiple times through the reflective cup 20, thereby reducing the divergence range of the light. Then, the first Fresnel lens 30 is used to collimate the light to form a small-angle light with good brightness uniformity. By reasonably arranging the sizes of the LED light board 10, the reflective cup 20, the first Fresnel lens 30 and the insulating glass 40, as well as the distances therebetween, the light emitted by the lighting system passes through the projection imaging system as much as possible to become effective light, thereby improving the light efficiency of the optical system and meeting the requirements of miniaturization and large screen of the single-chip LCD projector.

[0059] In the embodiment of the present application, the projection imaging system includes an LCD liquid crystal light valve 50 and a projection lens 80 .

[0060] The LCD light valve 50 can be a transmissive full-color LCD screen. When the light emitted by the LED light panel 10 passes through the LCD light valve 50, the liquid crystal unit controls the degree of light penetration by adjusting the transmittance, thereby forming an image. By adjusting the arrangement of liquid crystal molecules, precise control of light can be achieved, so that the LCD screen can present high-quality color images.

[0061] It should be noted that the single-chip LCD projector here refers to the number of liquid crystal panels used inside the projector. The single-chip LCD projector of the present application uses a liquid crystal panel (i.e., LCD liquid crystal light valve 50) to process all color information, and synthesizes a color image by alternately adjusting the transmittance of the three basic colors of red, green, and blue. Compared with the form of using multiple liquid crystal panels inside the projector in the related art, such as the 3LCD projection technology uses three liquid crystal panels, the single-chip liquid crystal projector of the embodiment of the present application only needs one liquid crystal panel, so it will be more economical in manufacturing cost, relatively light and thin in size and weight, easy to carry and install, and more energy-saving in power consumption.

[0062] The LCD liquid crystal light valve 50 is arranged on the side of the heat-insulating glass 40 facing away from the first Fresnel lens 30. In this way, the heat-insulating glass 40 can effectively isolate most of the heat and prevent the heat from being transmitted from the lighting system to the projection imaging system, thereby reducing the operating temperature of the entire projector. This helps to protect the internal components of the projector from being damaged by overheating and prolong the service life of the equipment. In addition, the LCD liquid crystal light valve 50 is arranged on the side of the heat-insulating glass 40 facing away from the first Fresnel lens 30, which can reduce the risk of deformation or failure of the LCD liquid crystal light valve 50 due to heat. The heat-insulating glass 40 effectively isolates the heat, maintains the stable operating temperature of the LCD liquid crystal light valve 50, and ensures the clarity and stability of the projected image. Then, the light transmitted by the lighting system will emit image light after passing through the LCD liquid crystal light valve 50, and the image light will be directed to the projection lens 80. The projection lens 80 is used to amplify the image light and project it out (such as projecting it onto a screen to form an image).

[0063] In order to reduce the heat generated by the single-chip LCD projector during operation and to increase the service life of the single-chip LCD projector, an internal circulation heat dissipation air duct is provided inside the single-chip LCD projector. The space between the first Fresnel lens 30 and the heat-insulating glass 40 and the space between the heat-insulating glass 40 and the LCD liquid crystal light valve 50 are usually designed as two air ducts for internal circulation heat dissipation. The spacing between these two air ducts needs to meet the needs of internal circulation heat dissipation and ensure the light efficiency of the optical system at the same time, and it should not be too small or too large. Therefore, the center distance between the first Fresnel lens 30 and the heat-insulating glass 40 is not less than 2 mm and not more than 4 mm. The center distance between the heat-insulating glass 40 and the LCD liquid crystal light valve 50 is not less than 5 mm and not more than 10 mm. In some embodiments, the center distance between the first Fresnel lens 30 and the heat-insulating glass 40 is 3 mm. The center distance between the heat-insulating glass 40 and the LCD liquid crystal light valve 50 is 7 mm.

[0064] It should be noted that the internal circulation heat dissipation is mainly for dissipating heat for the LCD liquid crystal light valve 50. The two air ducts together form a closed circulation space in which heat can be evenly distributed. The radiator arranged in the air duct can conduct heat to the outside for dissipation, thereby keeping the temperature of the system within an acceptable range.

[0065] See also Figure 2The projection lens 80 includes a first lens 81, a second lens 82, and a third lens 83 which are coaxially arranged in sequence along the direction of the outgoing light of the lens. The first lens 81 and the third lens 83 both have positive focal lengths, and the second lens 82 has negative focal lengths. Among them, the refractive index Nd1 of the first lens 81 satisfies: 1.65≤Nd1≤1.7, and the Abbe number Vd1 satisfies: 50≤Vd1≤60. The refractive index Nd2 of the second lens 82 satisfies: 1.65≤Nd2≤1.7, and the Abbe number Vd2 satisfies: 25≤Vd2≤35. The refractive index Nd3 of the third lens 83 satisfies: 1.60≤Nd3≤1.67, and the Abbe number Vd3 satisfies: 45≤Vd3≤55. By selecting the positive and negative focal lengths and refractive indices of the first lens 81, the second lens 82 and the third lens 83, the present application allows the light to converge and diverge to varying degrees through the positive and negative lenses in turn, thereby achieving a projection ratio of 1.25 and realizing a 1080P high-definition imaging rate.

[0066] It should be noted that the Abbe number is related to the dispersion ability of the lens. The Abbe number range values ​​of the first lens 81, the second lens 82 and the third lens 83 provided in the present application can help control the chromatic aberration of the lens. Chromatic aberration refers to the color shift or blurring of the image edge caused by the light of different wavelengths converging at different positions after passing through the lens. The embodiments of the present application can reduce the dispersion effect and improve the image quality. In addition, the selection of the Abbe number can also help reduce spherical aberration, that is, the change in the focal position of the lens under different incident angles. Spherical aberration can cause blurring and distortion of the image. The Abbe number range values ​​of the first lens 81, the second lens 82 and the third lens 83 provided in the present application can optimize the spherical aberration performance of the lens and improve the clarity and accuracy of the image.

[0067] The center distance between the first lens 81 and the second lens 82 may be 7 mm to 8 mm. In some embodiments, the center distance between the first lens 81 and the second lens 82 is 7.5 mm. The center distance between the second lens 82 and the third lens 83 is 9 mm to 10 mm. In some embodiments, the center distance between the second lens 82 and the third lens 83 may be 9.4 mm. By limiting the center distance between the first lens 81 and the second lens 82 and the center distance between the second lens 82 and the third lens 83, the clarity of the projection lens 80 is improved.

[0068] It should be noted that the center distance between the first lens 81 and the second lens 82 refers to the distance between the axis of the first lens 81 and the axis of the second lens 82 along the direction of the optical path, and the center distance between the second lens 82 and the third lens 83 refers to the distance between the axis of the second lens 82 and the axis of the third lens 83 along the direction of the optical path. In the field of lens technology, those skilled in the art can determine the axis position of the lens, and thus can clearly choose to set the distance between the two lenses.

[0069] The curvature radius R811 of the end surface of the first lens 81 on the side away from the second lens 82 is 45.3 mm, and the curvature radius R812 of the end surface of the first lens 81 on the side close to the second lens 82 is -143.1 mm.

[0070] The curvature radius R821 of the end surface of the second lens 82 close to the first lens 81 is -78.3 mm, and the curvature radius R822 of the end surface of the second lens 82 away from the first lens 81 is 48.1 mm.

[0071] The curvature radius R831 of the end surface of the third lens 83 close to the second lens 82 is -714.5 mm, and the curvature radius R832 of the end surface of the third lens 83 away from the second lens 82 is -55.7 mm.

[0072] In some embodiments, the projection imaging system further includes a second Fresnel lens 60. The center thickness of the second Fresnel lens 60 is 2.0 mm. The side of the second Fresnel lens 60 close to the LCD liquid crystal light valve 50 is substantially flat, and the surface of the side away from the LCD liquid crystal light valve 50 is a Fresnel surface. It is understandable that in the process of production and manufacturing, the surface of the second Fresnel lens 60 cannot be produced to be 100% flat. In this application, the term "substantially flat" means that a surface close to a flat surface is formed within the range allowed by the process error. The Fresnel surface has a plurality of concentric circular convex structures, wherein the surface shape of the Fresnel surface is an even-order aspheric surface, the radius of curvature is 46 mm, and the conic coefficient conic is -1.03. The second Fresnel lens 60 can collimate the light emitted by the LCD liquid crystal light valve 50, so that the light can be incident on the reflective surface of the reflector 70 in parallel, so that the reflector 70 can reflect the light to the projection lens 80.

[0073] The second Fresnel lens 60 can be made of polymethyl methacrylate (PMMA). Of course, in some other embodiments, the second Fresnel lens 60 can also be made of polycarbonate (PC), etc. Here, the present application does not limit the specific material of the second Fresnel lens 60. The size of the second Fresnel lens 60 in the embodiment of the present application is 89mm*52mm.

[0074] In order to reduce the length of the projection lens 80, a reflector 70 is added between the second Fresnel lens 60 and the first lens 81. Figure 3 The reflector 70 is tilted at 45° to reflect the light emitted from the LCD light valve 50 by 90° and then make it incident on the projection lens 80.

[0075] In some specific embodiments of the present application, the refractive index of the first lens 81 is 1.69, the refractive index of the second lens 82 is 1.67, and the refractive index of the third lens 83 is 1.66.

[0076] The center thickness T1 of the first lens 81 is 9.0 mm, the curvature radius R811 of the end surface away from the second lens 82 is 45.3 mm, the curvature radius R812 of the end surface close to the second lens 82 is -143.1 mm, and the Abbe number is 55.5.

[0077] The center thickness T2 of the second lens 82 is 4.0 mm, the curvature radius R821 of the end surface of the second lens 82 close to the first lens 81 is -78.3 mm, the curvature radius R822 of the end surface of the second lens 82 away from the first lens 81 is 48.1 mm, and the Abbe number is 32.2.

[0078] The center thickness T3 of the third lens 83 is 8.5 mm, the curvature radius R831 of the end surface of the third lens 83 close to the second lens 82 is -714.5 mm, the curvature radius R832 of the end surface of the third lens 83 away from the second lens 82 is -55.7 mm, and the Abbe number is 50.8.

[0079] The center thickness T5 of the second Fresnel lens 60 is 2.0 mm, wherein the surface close to the LCD liquid crystal light valve 50 is substantially a plane, and the surface away from the LCD liquid crystal light valve 50 is a Fresnel surface. The Fresnel surface is an even-order aspheric surface, with a curvature radius of 46 mm and a conic coefficient of -1.03.

[0080] The center distance between the first lens 81 and the second lens 82 is 7.5 mm, the center distance between the second lens 82 and the third lens 83 is 9.4 mm, the center distance between the reflector 70 and the first lens 81 is 45 mm, the center distance between the reflector 70 and the second Fresnel lens 60 is 32.8 mm, and the center distance between the second Fresnel lens 60 and the LCD liquid crystal light valve 50 is 9.8 mm.

[0081] The first lens 81 can be made of a material with a glass grade of H-ZBAF50, the second lens 82 can be made of a material with a glass grade of H-ZF2, and the third lens 83 can be made of a material with a glass grade of H-LAK51A. In addition, the diameter of the first lens 81 is 44 mm, the diameter of the second lens 82 is 40 mm, and the diameter of the third lens 83 is 48 mm. In this way, the requirement of a small lens volume can be met and the occupied space can be reduced.

[0082] Based on the projection lens 80 of the embodiment of the present application, the present application arranges the first lens 81, the second lens 82 and the third lens 83 in intervals along the direction of the outgoing light of the lens, and by selecting the positive and negative focal lengths and refractive indices of the first lens 81, the second lens 82 and the third lens 83, the light rays are converged and diverged to different degrees after passing through the positive and negative lenses in sequence. By optimizing the center thickness of the first lens 81, the second lens 82, the third lens 83 and the second Fresnel lens 60, and the center distance between each optical element, the resolution can fully match the 1080P display resolution of the LCD liquid crystal light valve 50, and the projection ratio is small and the aperture is large, so that the light efficiency of the overall optical system of the single-chip LCD projector of the present application can be increased to 5.0lm / W and above.

[0083] Figure 4 The above specific embodiment is the modulation transfer function curve corresponding to the projection lens 80 and the second Fresnel lens 60. The modulation transfer function (MTF) is a performance indicator of an optical system, which represents the system's ability to transmit signals of different spatial frequencies. The resolution of the 3.5-inch LCD liquid crystal light valve 50 is 1920*1080, the pixel size is 40.5 microns, and the corresponding spatial resolution is 12.3lp / mm. The full-field MTF of the projection lens 80 at 12.3lp / mm is greater than 0.2. Figure 4 In the figure, the full-field MTF of the projection molding system at 12.3lp / mm is greater than 0.2, indicating that the lens has a good transmission capability for the signal of this spatial frequency and can maintain a high image detail.

[0084] In summary, the projection lens 80 of the embodiment of the present application has a higher modulation transfer function at 12.3lp / mm, and can maintain higher image details; at the same time, its distortion error is also relatively small, and can provide better image quality and accuracy.

[0085] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of this application, it should be understood that if the terms "up", "down", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this application. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0086] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A single-chip LCD projector, characterized in that: Including lighting system and projection imaging system; The lighting system comprises an LED light board for providing lighting light, a reflective cup, a first Fresnel lens and a heat-insulating glass which are coaxially arranged in sequence along the propagation direction of the light emitted by the LED light board; Among them, the length of the effective light-emitting surface of the LED lamp board is not less than 9mm and not more than 11.5mm, and the width is not less than 6mm and not more than 9mm. The length of the incident port of the reflector cup is not less than 10mm and not more than 12.5mm, and the width is not less than 7mm and not more than 10mm. The length of the outlet is not less than 82mm and not more than 84mm, the width is not less than 45mm and not more than 48mm, and the vertical height is not less than 44mm and not more than 46mm. The length of the first Fresnel lens is not less than 85mm and not more than 90mm, the width is not less than 49mm and not more than 53mm, the thickness is not less than 1.6mm and not more than 2.2mm, and the focal length is not less than 55mm and not more than 65mm. The projection imaging system comprises an LCD liquid crystal light valve and a projection lens. The LCD liquid crystal light valve is arranged on a side of the heat-insulating glass facing away from the first Fresnel lens, and the light emitted from the LCD liquid crystal light valve is directed toward the projection lens.

2. The single-chip LCD projector according to claim 1, characterized in that: The first Fresnel lens is bonded to the exit of the reflective cup.

3. The single-chip LCD projector according to claim 1, characterized in that: The heat-insulating glass comprises a glass substrate and optical film layers arranged on two opposite surfaces of the glass substrate; The optical film layer on the side of the glass substrate close to the first Fresnel lens is a reflective polarizing film, and the optical film layer on the side away from the first Fresnel lens is an absorbing polarizing film.

4. The single-chip LCD projector according to claim 1, characterized in that: The length of the insulating glass is not less than 85 mm and not more than 90 mm, the width is not less than 49 mm and not more than 53 mm, and the thickness is not less than 0.8 mm and not more than 1.2 mm.

5. The single-chip LCD projector according to claim 1, characterized in that: The center distance between the first Fresnel lens and the heat-insulating glass is not less than 2 mm and not more than 4 mm; and / or The center distance between the heat-insulating glass and the LCD liquid crystal light valve is not less than 5 mm and not more than 10 mm.

6. The single-chip LCD projector according to any one of claims 1 to 5, characterized in that: The projection imaging system also includes a second Fresnel lens and a reflector; The reflector is tilted at 45° to reflect the light emitted from the LCD light valve by 90° and then enter the projection lens.

7. The single-chip LCD projector according to claim 6, characterized in that: The central thickness of the second Fresnel lens is not less than 1.6 mm and not more than 2.2 mm, the surface of the second Fresnel lens close to the LCD liquid crystal light valve is substantially a plane, and the surface of the second Fresnel lens away from the LCD liquid crystal light valve is a Fresnel surface; The Fresnel surface is an even-order aspheric surface, with a curvature radius of 46 mm and a conic coefficient of -1.

03.

8. The single-chip LCD projector according to claim 6, characterized in that: The length of the second Fresnel lens is not less than 85 mm and not more than 90 mm, and the width is not less than 49 mm and not more than 53 mm.

9. The single-chip LCD projector according to claim 6, characterized in that: The projection lens comprises a first lens, a second lens and a third lens which are coaxially arranged in sequence along the direction of the outgoing light of the lens; The first lens and the third lens both have positive refractive power, and the second lens has negative refractive power; The refractive index Nd1 of the first lens satisfies: 1.65≤Nd1≤1.7, and the Abbe number Vd1 satisfies: 50≤Vd1≤60; The refractive index Nd2 of the second lens satisfies: 1.65≤Nd2≤1.7, and the Abbe number Vd2 satisfies: 25≤Vd2≤35; The refractive index Nd3 of the third lens satisfies: 1.60≤Nd3≤1.67, and the Abbe number Vd3 satisfies: 45≤Vd3≤55.

10. The single-chip LCD projector according to claim 9, characterized in that: The curvature radius R811 of the end surface of the first lens on the side away from the second lens satisfies: 40mm≤R811≤50mm, and the curvature radius R812 of the end surface of the first lens on the side close to the second lens satisfies: -200mm≤R812≤-100mm; The curvature radius R821 of the end surface of the second lens close to the first lens satisfies: -100mm≤R821≤-50mm, and the curvature radius R822 of the end surface of the second lens away from the first lens satisfies: 40mm≤R822≤55mm; The curvature radius R831 of the end surface of the third lens close to the second lens satisfies: -1000mm≤R831≤-500mm, and the curvature radius R832 of the end surface of the third lens away from the second lens satisfies: -100mm≤R832≤-50mm.

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