High-resolution LCD projection lens
By employing a four-lens structure and a specially designed plastic aspherical lens, the problems of large size, high cost, and unstable imaging at high and low temperatures in LCD projection lenses have been solved, achieving a compact, low-cost, and high-resolution projection effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2026-03-24
AI Technical Summary
Existing LCD projection lenses suffer from problems such as large lens size, high cost, poor resolution, and unstable imaging at high and low temperatures.
It adopts a four-lens structure, including a first positive lens, a second negative lens, a third positive lens, and a Fresnel lens, all of which are plastic aspherical lenses. With a specific focal length and aperture design, the distance between the Fresnel lens and the LCD screen is limited, the lens projection ratio is within a reasonable range, and aberrations are corrected to achieve compactness and high resolution.
It achieves a compact lens structure, low cost, 1080P high resolution and high and low temperature imaging stability, effectively corrects aberrations, and is suitable for LCD projection devices.
Smart Images
Figure CN224035693U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to projection lens technical field, especially a high resolution LCD projection lens. BACKGROUND
[0002] At present, the LCD projection lens on the market usually adopts more glass lenses to ensure resolution and brightness requirements, and the lens cost is difficult to effectively control. Especially for 1080P high resolution lens, the lens size is large, miniaturization effect is limited, and the lens cost is high, and high and low temperature imaging is unstable. SUMMARY
[0003] The utility model provides a high resolution LCD projection lens has 1080P high resolution, compact structure, high and low temperature imaging stable advantage can effectively correct aberration in optical system.
[0004] The technical scheme of the utility model is as follows: a high resolution LCD projection lens, including first positive lens, second negative lens, diaphragm, third positive lens and fresnel lens arranged in sequence from object side to image side;The object side surface and the image side surface of the first positive lens are convex and concave in proper order, the object side surface and the image side surface of the second negative lens are concave and convex in proper order, the object side surface and the image side surface of the third positive lens are convex and concave in proper order;
[0005] The distance between the rear vertex of the image side of the third positive lens and the fresnel lens is L1, L1>65mm, 1<|f1 / f|<1.2, 0.93<|f2 / f3|<1.05, f1 is the focal length of the first positive lens, f2 is the focal length of the second negative lens, f3 is the focal length of the third positive lens, and f is the focal length of the lens optical system.
[0006] Further, the first positive lens, the second negative lens and the third positive lens are plastic aspheric lenses.
[0007] Further, the aperture of the projection lens satisfies Fno.≤2.8.
[0008] Further, the image side surface of the fresnel lens is provided with an LCD screen, and the distance between the fresnel lens and the LCD screen is L, 8mm<L<12mm.
[0009] Further, 1.2<|TR|<1.35, and TR is the lens projection ratio.
[0010] Further, the fresnel lens is a spherical lens or an aspheric lens.
[0011] Further, the fresnel lens is a plastic aspheric lens.
[0012] The utility model has the advantages that:
[0013] The LCD projection lens has the advantages of compact lens structure, low cost, and high resolution and high-temperature imaging stability.
[0014] The LCD projection lens has the advantages of compact lens structure, low cost, and high resolution and high-temperature imaging stability. BRIEF DESCRIPTION OF DRAWINGS
[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0016] Figure 1 It is a structure schematic diagram of the LCD projection lens;
[0017] Figure 2 It is a spherical aberration schematic diagram of the LCD projection at normal temperature;
[0018] Figure 3 It is a coma schematic diagram of the LCD projection;
[0019] Figure 4 It is a distortion schematic diagram of the LCD projection;
[0020] Figure 5 It is a Rayfan schematic diagram of the LCD projection at normal temperature.
[0021] The first positive lens 1, the second negative lens 2, the diaphragm 3, the third positive lens 4, the Fresnel lens 5, and the LCD screen 6. DETAILED DESCRIPTION
[0022] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.
[0023] As Figure 1As shown, a high-resolution LCD projection lens includes a first positive lens 1, a second negative lens 2, a diaphragm 3, a third positive lens 4 and a Fresnel lens 5 arranged in order from the object side to the image side; the object side and the image side of the first positive lens 1 are convex and concave in order, the object side and the image side of the second negative lens 2 are concave and convex in order, and the object side and the image side of the third positive lens 4 are convex and concave in order; the distance between the rear vertex of the image side of the third positive lens 4 and the Fresnel lens 5 is L1, and L1>65mm, which determines the back focal position of the optical machine, and a too small back focal length will cause the problem of optical path interference by the mechanism.
[0024] 1.2<|TR|<1.35, TR is the projection ratio of the lens, the smaller the projection ratio, the larger the projected picture at the same distance, and the higher the design difficulty, in the embodiment, |TR|=1.25.
[0025] The first positive lens 1, the second negative lens 2 and the third positive lens 4 are all plastic aspherical lenses.
[0026] The aperture of the projection lens satisfies Fno.≤2.8, which meets the brightness requirement of the lens.
[0027] The image side of the Fresnel lens 5 is provided with an LCD screen 6, and the Fresnel lens 5 is located between the third positive lens 4 and the LCD, which is used to reduce the size of the lens.
[0028] The distance between the Fresnel lens 5 and the LCD screen 6 is L, and 8mm<L<12mm. This distance needs to be determined by the optical machine, and too large or too small will be unfavorable to the resolution.
[0029] 1<|f1 / f|<1.2, 0.93<|f2 / f3|<1.05, f1 is the focal length of the first positive lens 1, f2 is the focal length of the second negative lens 2, f3 is the focal length of the third positive lens 4, and f is the focal length of the optical system of the lens. The focal length of the lens reflects the overall situation of the combination of the front and rear two surfaces of the lens, which is a structural parameter of the lens. The lens meeting the above limitation conditions can effectively correct the change amount of high and low temperature resolution. In the embodiment, |f1 / f|=1.09, |f2 / f3|=0.96.
[0030] The Fresnel lens 5 is a plastic aspherical lens. The aspherical surface of the Fresnel lens 5 can improve the overall resolution of the lens.
[0031] Table 1: Basic lens data of the embodiment
[0032]
[0033] In the above table, the side of the lens close to the object side is the object side, the side close to the image side is the image side, the radius of curvature R represents the radius of curvature value of the corresponding surface, the unit is mm, the surface interval D represents the lens thickness or the interval value between lenses, the unit is mm, the above table also gives the refractive index Nd and Abbe number Vd of the lens relative to d light (wavelength is 587.6nm).
[0034] In the embodiment, the first positive lens 1, the second negative lens 2 and the third positive lens 4 are all aspherical lenses, the coefficients of the aspherical lenses are taken as the origin of the lens surface center, the optical axis is the x axis, and the aspherical surface type expression of the lens surface satisfies the following formula:
[0035]
[0036] Wherein, X is the depth of the aspherical lens, the unit is mm, Y is the distance from the optical axis to the lens surface, the unit is mm, C is the radius of curvature of the aspherical lens, C=1 / R, k is the conic constant, b, c, d, e, f, g and h are the coefficients of the aspherical lens.
[0037] Table 2: specific parameters of aspherical lens coefficients
[0038]
[0039] Table 3: optical system parameters
[0040] f FNO. TR TTL LCD size 86 2.8 1.25 107 3 inches
[0041] In the above table, the unit of the paraxial focal length f is mm, and the FNO. is the lens aperture value. The unit of the total optical length TTL is mm.
[0042] The LCD projection lens of the embodiment is tested at room temperature, Figures 2-5 The ball aberration diagram, the astigmatism diagram, the distortion diagram and the Rayfan diagram at room temperature are shown in the following table.
[0043] It can be seen from Table 3 and Figures 2-5 It can be seen that the various aberrations of the LCD projection lens of the embodiment are well corrected, and the LCD projection lens can be applied to the LCD projection equipment.
[0044] The above only describes the preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A high-resolution LCD projection lens, characterized in that: The lens has 1080P resolution and includes a first positive lens, a second negative lens, an aperture, a third positive lens, and a Fresnel lens arranged in sequence from the object side to the image side; the object side and image side of the first positive lens are convex and concave respectively, the object side and image side of the second negative lens are concave and convex respectively, and the object side and image side of the third positive lens are convex and concave respectively. The distance between the rear vertex of the image side of the third positive lens and the Fresnel lens is L1, where L1 > 65 mm; 1 < |f1 / f| < 1.2, 0.93 < |f2 / f3| < 1.05, where f1 is the focal length of the first positive lens, f2 is the focal length of the second negative lens, f3 is the focal length of the third positive lens, and f is the focal length of the lens optical system. The first positive lens, the second negative lens, and the third positive lens are all plastic aspherical lenses; Fresnel lenses are spherical lenses; An LCD screen is mounted on the image side of the Fresnel lens. The distance between the Fresnel lens and the LCD screen is L, where 8mm < L < 12mm. The LCD screen is 3 inches.
2. The high-resolution LCD projection lens according to claim 1, characterized in that: The aperture of the projection lens is ≤2.
8.
3. A high-resolution LCD projection lens according to claim 1, characterized in that: 1.2 < |TR| < 1.35, where TR is the lens projection ratio.