A projection lens for LCD projection

Abstract

The present application relates to the technical field of projection lens, specifically is a kind of projection lens for LCD projection, the present application includes convex-concave negative lens, convex-concave positive lens, double-concave negative lens, double-convex aspherical positive lens, convex-concave aspherical negative lens, fresnel lens, the convex-concave positive lens is located between convex-concave negative lens and double-concave negative lens, double-concave negative lens is located between convex-concave positive lens and double-convex aspherical positive lens, double-convex aspherical positive lens is located between double-concave negative lens and convex-concave aspherical negative lens;By adopting the optical structure of 5 groups of lens combination, projection lens projection ratio 0.69:1, can project picture as 20 when projection distance 0.31m, when using, the requirement of space size is lower, wherein two groups of lenses adopt the aspherical lens of optical plastic injection molding, the adoption of the lens corrects the off-axis aberration and optical relative distortion generated due to field of view increases, processing technology is good, cost is low can satisfy the requirement of mass production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of projection lens, in particular to a projection lens for LCD projection. BACKGROUND

[0002] The single-chip LCD projector has simple structure and low cost, and has a large product sales volume. In recent years, due to the development of the manufacturing technology of the LCD chip, the resolution has been greatly improved. At present, the pixel points of the 2.1-inch chip of the LCD can reach 1280x720P. The improvement of the resolution expands the use range of the projector, expands the game machine market to the entertainment market and the product exhibition advertising market, and even enters the family to replace the television set. The projection lens is one of the important components of the LCD projection.

[0003] The existing single-chip LCD projection lens is formed by combining multiple groups of projection lenses. The projection ratio is generally 1.3-1.6. Taking the projection ratio of 1.4 as an example, if a large screen of 100 inches is projected, the surface distance of the front edge lens of the machine from the screen needs to be about 3.1 m to realize the projection.

[0004] However, the prior art has defects. The projection ratio is large, and the use requires a large projection space. The existing projection lens has a large field of view, which produces axial aberration and optical relative distortion, and affects the projection effect of the LCD projector. Therefore, a projection lens for LCD projection is proposed. SUMMARY

[0005] The present application relates to the field of projection lens, in particular to a projection lens for LCD projection.

[0006] The present application relates to the field of projection lens, in particular to a projection lens for LCD projection.

[0007] A projection lens for LCD projection, comprising a convex-concave negative lens, a convex-concave positive lens, a double-concave negative lens, a double-convex aspherical positive lens, a convex-concave aspherical negative lens, and a Fresnel lens. The convex-concave positive lens is located between the convex-concave negative lens and the double-concave negative lens. The double-concave negative lens is located between the convex-concave positive lens and the double-convex aspherical positive lens. The double-convex aspherical positive lens is located between the double-concave negative lens and the convex-concave aspherical negative lens. The convex-concave aspherical negative lens is located between the double-convex aspherical positive lens and the Fresnel lens. An aperture stop is arranged between the convex-concave positive lens and the double-concave negative lens. The double-convex aspherical positive lens and the convex-concave aspherical negative lens are both made of optical plastic by injection molding.

[0008] Preferably, the radius of R1 of the convex-concave negative lens ranges from 79 to 81 mm, the radius of R2 ranges from 25.8 to 26.3 mm, the thickness t is 1.9 to 2.1 mm, the refractive index n is 1.62 to 1.65, and the air gap d is 27.5 to 28.2 mm.

[0009] Preferably, the radius of R3 of the convex-concave positive lens ranges from 21.5 to 22.9 mm, the radius of R4 ranges from 605.5 to 615.5 mm, the thickness t is 8.1 to 8.4 mm, the refractive index n is 1.69 to 1.73, and the air gap d is 4.5 to 4.9 mm.

[0010] Preferably, the diameter of the aperture diaphragm ranges from 15.9 to 16.1 mm, and the air gap d is 3.55 to 3.95 mm.

[0011] Preferably, the radius of R6 of the double-concave negative lens ranges from -27.3 to -28.1 mm, the radius of R7 ranges from 138.8 to 140.5 mm, the thickness t is 1.38 to 1.53 mm, the refractive index n is 1.79 to 1.81, and the air gap d is 0.15 to 0.25 mm.

[0012] Preferably, the radius of R8 of the double-convex aspheric positive lens ranges from 70.15 to 70.78 mm, the thickness t is 6.8 to 7.3 mm, the refractive index n is 1.51 to 1.55, the air gap d is 0.15 to 0.21 mm, and the radius of R9 ranges from -15.15 to -15.56 mm.

[0013] Preferably, the radius of R10 of the convex-concave aspheric negative lens ranges from 19.25 to 19.91 mm, the thickness t is 2.35 to 2.63 mm, the refractive index n is 1.51 to 1.55, the radius of R11 ranges from 13.15 to 13.35 mm, and the air gap d is 31.77 to 32.05 mm.

[0014] Preferably, the radius of R12 of the Fresnel lens is a plane, the thickness t is 1.6 to 2.1 mm, the refractive index n is 1.47 to 1.51, the radius of R13 ranges from 22.15 to 22.85 mm, the tooth spacing ranges from 0.15 to 0.25 mm, and the air gap d is 6.15 to 6.65 mm.

[0015] Advantages of the present application:

[0016] The present application adopts the optical structure of 5 groups of lens combination, the projection lens projects the ratio of 0.69:1, and can project the picture of 20" when the projection distance is 0.31m, the space size requirement is low in use, the aspheric lens of optical plastic injection molding is adopted in two groups of lenses, the adoption of the lens corrects the off-axis aberration and optical relative distortion caused by the increase of the field of view, the processing technology is good, the cost is low, and the requirement of mass production can be met. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0018] Figure 1 is the optical glass arrangement diagram with light rays of the present application;

[0019] Figure 2 is the radius arrangement diagram without light rays of the present application;

[0020] Figure 3 is the spot diagram SPT data of the present application;

[0021] Figure 4 is the optical transfer function curve of the present application;

[0022] Figure 5 is the magnification chromatic aberration curve diagram of the present application;

[0023] Figure 6 is the optical relative distortion curve diagram of the present application;

[0024] The reference signs in the drawings are as follows:

[0025] 1, convex-concave negative lens; 2, convex-concave positive lens; 3, aperture stop; 4, double-concave negative lens; 5, double-convex aspheric positive lens; 6, convex-concave aspheric negative lens; 7, Fresnel lens. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the scope of protection of the present application.

[0027] A projection lens for LCD projection, such as Figures 1-6As shown, including convex-concave negative lens 1, convex-concave positive lens 2, double-concave negative lens 4, double-convex aspherical positive lens 5, convex-concave aspherical negative lens 6, Fresnel lens 7, the convex-concave positive lens 2 is located between the convex-concave negative lens 1 and the double-concave negative lens 4, the double-concave negative lens 4 is located between the convex-concave positive lens 2 and the double-convex aspherical positive lens 5, the double-convex aspherical positive lens 5 is located between the double-concave negative lens 4 and the convex-concave aspherical negative lens 6, the convex-concave aspherical negative lens 6 is located between the double-convex aspherical positive lens 5 and the Fresnel lens 7, the convex-concave positive lens 2 and the double-concave negative lens 4 are provided with an aperture stop 3, and the double-convex aspherical positive lens 5 and the convex-concave aspherical negative lens 6 are both formed by optical plastics injection molding.

[0028] 5 groups of lenses and the Fresnel lens 7 are sequentially installed in the LCD projector, the aperture stop 3 is installed between the convex-concave positive lens 2 and the double-concave negative lens 4, the light source is located on the side of the convex-concave negative lens 1 away from the convex-concave positive lens 2, and light rays pass through the convex-concave negative lens 1, the convex-concave positive lens 2, the double-concave negative lens 4, the double-convex aspherical positive lens 5, the convex-concave aspherical negative lens 6 and the Fresnel lens 7 with high-order terms in sequence to generate the refraction condition as shown in the figure. Figure 2

[0029] By adopting the optical structure of the 5 groups of lens combination, the projection ratio of the projection lens is 0.69:1, the projection screen can be 20" when the projection distance is 0.31m, the space size requirement is low in use, the projection lens can be installed on a desktop as a learning machine, so that the small tablet computer can be replaced, two groups of lenses adopt the aspherical lens formed by optical plastics injection molding, the lens corrects the off-axis aberration and optical relative distortion caused by the increased field of view, the processing technology is good, the cost is low, and the large-batch production requirement can be met.

[0030] The present application is suitable for a single-chip LCD projection light machine, the LCD chip size is 2.1 inches, the pixel point is 1280x720P, the projection ratio is 0.69:1, the offset is 100%, the optical transfer function MTF@14Lp is greater than or equal to 0.3, the TV distortion is less than or equal to 0.3%, the rate of color difference is less than or equal to 20λm, and the machine can continuously work at a temperature of less than or equal to 80°.

[0031] The focal length of the convex-concave negative lens 1 is fa; the focal length of the convex-concave positive lens 2 is fb; the focal length of the double-concave negative lens 4 is fc; the focal length of the double-convex aspherical positive lens 5 is fd; the focal length of the convex-concave aspherical negative lens 6 is fe; and the focal length of the Fresnel lens 7 is ff.

[0032] The main performance indicators of the short projection ratio back projection lens of the present application are: effective focal length f'=35.19mm, relative aperture F=2.64, rear working distance LF'=40.27mm, total length of optical system 98.6mm, and resolution is 1280x720P pixels.

[0033] As​ Figures 1-6 As shown in the figure, the radius of R1 of the convex-concave negative lens 1 ranges from 79 to 81 mm, the radius of R2 ranges from 25.8 to 26.3 mm, the thickness t is 1.9-2.1 mm, the refractive index n is 1.62-1.65, the air gap d is 27.5-28.2 mm, and the lens should be strictly controlled according to the above data during lens processing.

[0034] As shown in the figure, the radius of R1 of the convex-concave negative lens 1 ranges from 79 to 81 mm, the radius of R2 ranges from 25.8 to 26.3 mm, the thickness t is 1.9-2.1 mm, the refractive index n is 1.62-1.65, the air gap d is 27.5-28.2 mm, and the lens should be strictly controlled according to the above data during lens processing. Figures 1-6 As shown in the figure, the radius of R3 of the convex-concave positive lens 2 ranges from 21.5 to 22.9 mm, the radius of R4 ranges from 605.5 to 615.5 mm, the thickness t is 8.1-8.4 mm, the refractive index n is 1.69-1.73, the air gap d is 4.5-4.9 mm, and the convex-concave positive lens 2 and other lenses should be avoided during lens installation. Lens installation is reversed, and positive and negative inversion is avoided.

[0035] As shown in the figure, the radius of R3 of the convex-concave negative lens 1 ranges from 79 to 81 mm, the radius of R2 ranges from 25.8 to 26.3 mm, the thickness t is 1.9-2.1 mm, the refractive index n is 1.62-1.65, the air gap d is 27.5-28.2 mm, and the lens should be strictly controlled according to the above data during lens processing. Figures 1-6 As shown in the figure, the diameter of the aperture stop 3 ranges from 15.9 to 16.1 mm, the air gap d is 3.55-3.95 mm, and the aperture stop 3 is installed between the convex-concave positive lens 2 and the double-concave negative lens 4.

[0036] As shown in the figure, the radius of R3 of the convex-concave negative lens 1 ranges from 79 to 81 mm, the radius of R2 ranges from 25.8 to 26.3 mm, the thickness t is 1.9-2.1 mm, the refractive index n is 1.62-1.65, the air gap d is 27.5-28.2 mm, and the lens should be strictly controlled according to the above data during lens processing. Figures 1-6 As shown in the figure, the radius of R6 of the double-concave negative lens 4 ranges from -27.3 to 28.1 mm, the radius of R7 ranges from 138.8 to 140.5 mm, the thickness t is 1.38-1.53 mm, the refractive index n is 1.79-1.81, the air gap d is 0.15-0.25 mm, and the double-concave negative lens 4 is close to the double-convex aspherical positive lens 5.

[0037] As shown in the figure, the radius of R3 of the convex-concave negative lens 1 ranges from 79 to 81 mm, the radius of R2 ranges from 25.8 to 26.3 mm, the thickness t is 1.9-2.1 mm, the refractive index n is 1.62-1.65, the air gap d is 27.5-28.2 mm, and the lens should be strictly controlled according to the above data during lens processing. Figures 1-6 As shown in the figure, the radius of R8 of the double-convex aspherical positive lens 5 ranges from 70.15 to 70.78 mm, the thickness t is 6.8-7.3 mm, the refractive index n is 1.51-1.55, the air gap d is 0.15-0.21 mm, and the radius of R9 ranges from -15.15 to 15.56 mm.

[0038] The standard equation of the aspherical surface is as follows:

[0039]

[0040] In the above formula, C=1 / R.

[0041] The radius of R8 ranges from 70.15 to 70.78 mm, K=-1;

[0042] A1=0;

[0043] A2=1.7384327E-005;

[0044] A3=-4.3251934E-007;

[0045] A4 = 8.6127748E-009;

[0046] A5 = -4.2544656E-011;

[0047] A6 = 7.4143915E-014;

[0048] A7 = 0;

[0049] The thickness t is 6.8-7.3 mm, the refractive index n is 1.51-1.55, and the air interval d is 0.15-0.21 mm.

[0050] The radius of R9 is -15.15-15.56 mm, and K = -2.04065;

[0051] A1 = 0;

[0052] A2 = 6.6521894E-005;

[0053] A3 = -3.0647421E-007;

[0054] A4 = -2.0890194E-009;

[0055] A5 = 6.8123854E-011;

[0056] A6 = -2.2683112E-013;

[0057] A7 = 0;

[0058] As shown in Figures 1-6 , the radius of R10 of the convex-concave aspherical negative lens 6 is 19.25-19.91 mm, the thickness t is 2.35-2.63 mm, the refractive index n is 1.51-1.55, the radius of R11 is 13.15-13.35 mm, and the air interval d is 31.77-32.05 mm.

[0059] The radius of R10 is 19.25-19.91 mm, and K = -18.55335;

[0060] A1 = 0;

[0061] A2 = 7.282503E-006;

[0062] A3 = -2.3438812E-007;

[0063] A4 = 1.7758118E-009;

[0064] A5 = -4.0538795E-012;

[0065] A6 = 2.2476735E-015;

[0066] A7 = 0;

[0067] The thickness t is 2.35-2.63 mm; the refractive index n ranges from 1.51 to 1.55.

[0068] The radius of R11 ranges from 13.15 to 13.35 mm, and K = -8.532375;

[0069] A1 = 0;

[0070] A2 = -2.5890717E-005;

[0071] A3 = 1.5330088E-007;

[0072] A4 = -7.6885275E-010;

[0073] A5 = 3.1022559E-012;

[0074] A6 = -4.7757313E-015;

[0075] A7 = 0;

[0076] The air gap d ranges from 31.77 to 32.05 mm.

[0077] As shown in Figures 1-6 , the Fresnel lens 7 has a radius R12 of 22.15-22.85 mm, a thickness t of 1.6-2.1 mm, a refractive index n of 1.47-1.51, a radius R13 of 22.15-22.85 mm, a tooth spacing of 0.15-0.25 mm, and an air gap d of 6.15-6.65 mm.

[0078] The radius of R13 ranges from 22.15 to 22.85 mm; K = -1; the tooth spacing ranges from 0.15 to 0.25 mm;

[0079] A1 = 0;

[0080] A2 = 4.1816E-006;

[0081] A3 = -5.8183E-009;

[0082] A4 = 1.6399E-012;

[0083] A5 = 0;

[0084] A6 = 0;

[0085] A7 = 0;

[0086] The air gap d ranges from 6.15 to 6.65 mm.

[0087] The working principle of the projection lens for LCD projection provided by the application is as follows:

[0088] By adopting the optical structure of 5 groups of lens combinations, the projection lens projects a projection ratio of 0.69:1, and can project a 20" picture at a projection distance of 0.31 m, and the space size requirement is low during use. Two groups of lenses adopt optical plastic injection molding aspherical lenses, the adoption of the lenses corrects the off-axis aberration and optical relative distortion caused by the increase of the field of view, has good processing technology, low cost and can meet the requirements of mass production.

[0089] The above shows and describes the basic principles, main features and advantages of the application. Those skilled in the art should understand that the application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the application. Without departing from the spirit and scope of the application, various changes and improvements can be made to the application, and these changes and improvements all fall within the scope of the claimed application.

Claims

1. A projection lens for LCD projection, comprising a convex-concave negative lens (1), a convex-concave positive lens (2), a biconcave negative lens (4), a biconvex aspheric positive lens (5), a convex-concave aspheric negative lens (6), and a Fresnel lens (7), characterized in that: The convex-concave positive lens (2) is located between the convex-concave negative lens (1) and the biconcave negative lens (4), the biconcave negative lens (4) is located between the convex-concave positive lens (2) and the biconvex aspheric positive lens (5), the biconvex aspheric positive lens (5) is located between the biconcave negative lens (4) and the convex-concave aspheric negative lens (6), the convex-concave aspheric negative lens (6) is located between the biconvex aspheric positive lens (5) and the Fresnel lens (7), an aperture light bar (3) is provided between the convex-concave positive lens (2) and the biconcave negative lens (4), both the biconvex aspheric positive lens (5) and the convex-concave aspheric negative lens (6) are made of optical plastic injection molding, the projection lens has a throw ratio of 0.69:1, and can project a 20" image at a projection distance of 0.31 m.

2. The projection lens for LCD projection according to claim 1, wherein: The radius of R1 of the convex-concave negative lens (1) is in the range of 79-81 mm, the radius of R2 is in the range of 25.8-26.3 mm, the thickness t is in the range of 1.9-2.1 mm, the refractive index n is in the range of 1.62-1.65, and the air space d is in the range of 27.5-28.2 mm.

3. The projection lens for LCD projection according to claim 1, characterized in that: The radius range of R3 of the convex-concave positive lens (2) is 21.5-22.9 mm, the radius range of R4 is 605.5-615.5 mm, the thickness t is 8.1-8.4 mm, the refractive index n is 1.69-1.73, and the air interval d is 4.5-4.9 mm.

4. The projection lens for LCD projection according to claim 1, wherein: The diameter of the aperture light barrier (3) ranges from 15.9 to 16.1 mm, and the air gap d ranges from 3.55 to 3.95 mm.

5. The projection lens for LCD projection according to claim 1, wherein: The radius range of R6 of the biconcave negative lens (4) is -27.3-28.1 mm, the radius range of R7 is 138.8-140.5 mm, the thickness t is 1.38-1.53 ​​mm, the refractive index n is 1.79-1.81, and the air gap d is 0.15-0.25 mm.

6. The projection lens for LCD projection according to claim 1, wherein: The radius range of R8 of the biconvex aspheric positive lens (5) is 70.15-70.78 mm, the thickness t is 6.8-7.3 mm, the refractive index n is 1.51-1.55, the air gap d is 0.15-0.21 mm, and the radius range of R9 is -15.15-15.56 mm.

7. The projection lens for LCD projection according to claim 1, wherein: The radius range of R10 of the convex-concave aspheric negative lens (6) is 19.25-19.91 mm, the thickness t is 2.35-2.63 mm, the refractive index n is 1.51-1.55, the radius range of R11 is 13.15-13.35 mm, and the air gap d is 31.77-32.05 mm.

8. The projection lens for LCD projection according to claim 1, wherein: The radius of R12 of the Fresnel lens (7) is flat, the thickness t is 1.6-2.1 mm, the refractive index n is 1.47-1.51, the radius range of R13 is 22.15-22.85 mm, the tooth spacing range is 0.15-0.25 mm, and the air spacing d is 6.15-6.65 mm.

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