CN211554449U - Optical lens for projection - Google Patents

Abstract

The utility model provides an optical lens for projection, optical lens for projection includes: a concave reflector arranged in order from the object side to the image side, a first lens group with negative focal power, and a positive and a negative shift along the optical axis of the optical lens for projectionA movable second lens group, a third lens group with positive focal power and a galvanometer, wherein the relative aperture FNo of the projection optical lens satisfies FNo ∈ [1.8, 2.2%](ii) a Focal length f of the moving lens group₂And the focal length f of the optical lens for projection satisfies:

the utility model has the advantages of undistorted, big light ring, image space heart far away, 4K formation of image under the wide-angle.

Description

Optical lens for projection

Technical Field

The utility model relates to an optical lens, in particular to optical lens for ultra-short focus projection.

Background

At present, projectors are widely used, for example, in the educational industry, an optical lens for projection is a core module of a projector, but generally, the optical lens for projection has the disadvantages of large spherical aberration, poor quality of peripheral images, large length, large angle, large distortion, large astigmatism, large axial chromatic aberration, and the like, for example:

CN2018104678873 discloses an ultra-large projection range projection optical system, specifically comprising: be provided with the first lens battery static relative to the DMD chip between DMD chip and the speculum, the focal power of first lens battery is negative, be provided with the second lens battery that can move between the first lens battery of DMD chip between DMD chip and the first lens battery, the focal power of second lens battery is positive, be provided with the third lens battery that can move between DMD chip and second lens battery between DMD chip and the second lens battery, the focal power of third lens battery is negative, be provided with the fourth lens battery static relative to the DMD chip between DMD chip and the third lens battery, the focal power of fourth lens battery is positive.

CN2017203198140 discloses an ultra-short-focus projection optical device, specifically comprising: the first lens group can move back and forth relative to the DMD chip, and the focal power of the first lens group is positive; the second lens group can move back and forth relative to the DMD chip, and the focal power of the second lens group is positive; the third lens group can move back and forth relative to the DMD chip, and the focal power of the third lens group is negative; and the focal power of the fourth lens group is positive relative to the fourth lens group which is static relative to the DMD chip.

SUMMERY OF THE UTILITY MODEL

For solving not enough among the above-mentioned prior art scheme, the utility model provides an optical lens for projection of good reliability, big light ring, wide-angle and distortionless, image space heart far away, 4K formation of image.

The utility model aims at realizing through the following technical scheme:

an optical lens for projection, comprising:

the projection optical lens comprises a concave reflecting mirror, a first lens group, a second lens group, a third lens group and a galvanometer, wherein the concave reflecting mirror, the first lens group, the second lens group, the third lens group and the galvanometer are arranged in sequence from an object side to an image side; the third lens group comprises at least two lenses, and a diaphragm is arranged between the lenses of the third lens group;

the relative aperture FNo of the optical lens for projection satisfies: FNo is belonged to [1.8,2.2 ];

focal length f of the second lens group₂And the focal length f of the optical lens for projection satisfies:

compared with the prior art, the utility model discloses the beneficial effect who has does:

1. the reliability is good;

the number of the second lens groups is less, namely, the number of the moving lenses is less, so that the structural complexity and the cost are reduced, and the running reliability is improved;

2. the large angle has no distortion;

the lens of the first lens group is in a funnel-shaped design, and the optical distortion is ensured to be less than 1% together by matching with the optimization of the aspheric surface type of the reflecting surface of the reflector, such as the selection of curvature and K value;

3. a large aperture;

the second lens group can adjust the aberration caused by the size change of the picture and can also adjust the spherical aberration and the coma introduced by the large aperture in the moving process;

4. high peripheral brightness ratio;

the lens adjacent to the galvanometer (i.e. the lens closest to the galvanometer) in the third lens group is a second aspheric lens, and the focal length and the distance (from the lens to the galvanometer) of the lens meet special conditions, so that the image quality is ensured, and meanwhile, the high peripheral brightness ratio is realized, thereby improving the overall efficiency of the lens;

5. 4K imaging is realized;

the second lens group comprises at least one third aspheric lens, particularly a lens adjacent to (i.e. closest to) the diaphragm, and the curvature and the K value are specially designed, so that the astigmatism and the axial chromatic aberration of the lens can be reduced to the maximum extent in the moving focusing process, and the requirement of 4K imaging is met;

the first lens of the second lens group meets the range of high refractive index and low Abbe number so as to ensure that the optical coma aberration meets the requirement of 4K imaging;

6. image space telecentricity;

the third lens group adopts the continuous use of the tri-cemented and the bi-cemented lenses, so that the divergence angles of the upper light and the lower light are closer, and the telecentricity of the lens is ensured to be less than 0.1 degree.

Drawings

The disclosure of the present invention will become more readily understood with reference to the accompanying drawings. As is readily understood by those skilled in the art: these drawings are only intended to illustrate the technical solution of the present invention and are not intended to limit the scope of the present invention. In the figure:

fig. 1 is a schematic structural view of an optical lens for projection according to embodiment 1 of the present invention;

fig. 2 is a schematic structural view of an optical lens for projection according to embodiment 2 of the present invention;

fig. 3 is a schematic diagram of a projection optical lens according to embodiment 3 of the present invention.

Detailed Description

Fig. 1-3 and the following description depict alternative embodiments of the invention to teach those skilled in the art how to make and reproduce the invention. For the purpose of teaching the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations or substitutions from these embodiments that will be within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. Accordingly, the present invention is not limited to the following alternative embodiments, but is only limited by the claims and their equivalents. In the following embodiments, when the unit of the focal length is not indicated, the unit of the focal length is mm.

Example 1:

fig. 1 schematically shows a schematic structural diagram of an optical lens for projection according to embodiment 1 of the present invention, and as shown in fig. 1, the optical lens for projection includes:

the projection optical lens comprises a concave reflector 1, a first lens group, a second lens group, a third lens group and a galvanometer, wherein the concave reflector 1 is arranged from the object side to the image side in sequence, the first lens group is fixedly arranged and has negative focal power, the second lens group has positive focal power and moves in the positive direction and the reverse direction along the optical axis of the projection optical lens, and the third lens group has positive focal power. The third lens group can be fixedly arranged, and preferably, the third lens group can also be movably arranged, so that the distance between the third lens group and the sensor can be adjusted, namely, the distance between the third lens group and the image surface is adjusted adaptively, and the adjustment range is small. The third lens group comprises at least two lenses, and the diaphragm is arranged between the lenses of the third lens group.

The relative aperture FNo of the optical lens for projection satisfies FNo ∈ [1.8, 2.2%]. Focal length f of the first lens group₁Focal length f of the second lens group₂Focal length f of the third lens group₃And the focal length f of the optical lens for projection satisfies:

preferably, f₁∈[-40mm,-25mm]，f₂∈[60mm,140mm]；f₃∈[15mm,35mm]；f∈[1.6mm,2.2mm]。

In order to achieve distortion-free under large angles, the first lens group further comprises at least one first aspheric lens, and a cross-sectional contour line of at least one side surface of the first aspheric lens on one reference surface where the optical axis is located comprises a first section located in the middle and two second sections located on two sides of the first section respectively; the center of curvature of each point of the first segment is located on one side of the cross-sectional contour line, and the center of curvature of each point of the second segment is located on the other side of the cross-sectional contour line. The arrangement may be such that the first section is concave into the first aspheric lens and each of the second sections is convex outward of the first aspheric lens. Alternatively, if desired, the first section may be designed to be arched outward of the first aspheric lens, and each of the second sections may be recessed inward of the first aspheric lens. The projection surface of the first aspheric lens can be designed with the above surface structure.

In some cases, the above surface structure of the first aspheric lens may be referred to as a bi-sigmoid structure, and, optionally,

optionally, the reflective surface of the concave mirror is an aspheric surface, and the reflective surface and the transmissive surface of the first lens group adjacent to the concave mirror satisfy:

R_{inverse direction}Is the radius of curvature, K, of the reflecting surface_{Inverse direction}Is the K value, R, of the reflecting surface_1-1Is the radius of curvature of the transmission surface, K_1-1Is the K value of the transmission surface.

In order to ensure that the lens telecentricity is less than 0.1 degree, further, the third lens group comprises:

the three-cemented lens group comprises three lenses with negative, positive and negative focal powers which are sequentially arranged; focal length f of triple cemented lens group_3-0-3Satisfies the following conditions:

specifically, f is less than or equal to 15mm_3-0-3|≤25mm；

Two cemented lens groups including two lenses with positive and negative focal powers arranged in sequence, and focal length f of the two cemented lens groups_3-0-2And focal length f of triple cemented lens group_3-0-3Satisfies the following conditions:

and light sequentially passes through the diaphragm, the three cemented lens group and the two cemented lens group. In the current arrangement state, the lens arrangement mode is better, two continuous lenses with negative focal power are not available, and the chromatic aberration is good.

In order to improve the peripheral light ratio, the lens of the third lens group adjacent to the galvanometer is a second aspheric lens, and the following conditions are satisfied:

f_3-0-1d is the distance from the second aspheric lens to the galvanometer.

In order to reduce astigmatism and axial chromatic aberration and satisfy the requirement of 4K imaging, further, a lens of the second lens group adjacent to the stop is a third aspheric lens, and two aspheric transmission surfaces satisfy:

R_2-0-1is the radius of curvature, R, of the first transmission surface of the third aspheric lens_2-0-2Is the radius of curvature, K, of the second transmission surface of the third aspheric lens_2-0-1Is the value of K, of the first transmission surface_2-0-2Is the K value of the second transmission surface.

In order to reduce coma aberration so as to meet the requirement of 4K imaging, further, a lens of the second lens group adjacent to the first lens group is a first lens. The first lens satisfies:

1.9≤N_d2≤2，15≤V_d2≤25；N_d2is the refractive index, V, of the first lens_d2Is the abbe number of the first lens.

Example 2:

according to the utility model discloses embodiment 1's optical lens's for projection application example.

As shown in fig. 1, in the present application example;

the reflecting surface of the concave reflecting mirror 1 is an aspheric surface; the first lens group includes a first aspherical lens G1, f₁∈[-35mm,-25mm]。

The second lens group includes:

lenses G2-G4 having negative, positive, and negative powers, respectively, disposed in order from the object side to the image side in the optical axis direction, wherein the lens G4 adjacent to the stop is a third aspherical lens;

the third lens group includes:

lenses G5-G11 having, in order from the object side to the image side in the optical axis direction, powers of positive, negative, positive, and positive, respectively, wherein: the lens G11 adjacent to the galvanometer is a second aspheric lens; lenses G6-G8 are triple cemented lens groups, and lenses G9-G10 are double cemented lens groups;

table 1: and (5) lens structure parameters.

Table 2: parameters of each aspherical lens

Coefficient of aspheric surface

G1-R1

G1-R2

G4-R1

G4-R2

G11-R1

G11-R2

Mirror

Radius of Y

46.67

-30.22

-369.43

-222.51

-36.04

24.29

-44.71

Conic constant (K)

0.80

-4.89

0.00

71.62

0.00

-0.27

-0.71

Coefficient of 4 th order (A)

-1.55E-05

2.78E-05

-5.58E-05

-1.03E-04

1.15E-05

-3.05E-05

4.95E-07

Coefficient of order 6 (B)

2.09E-08

-2.39E-08

1.32E-07

6.09E-08

-4.49E-08

-1.66E-08

-8.37E-11

Coefficient of order 8 (C)

-2.09E-11

2.29E-11

6.93E-10

1.46E-09

1.50E-10

9.21E-11

5.06E-15

Coefficient of order 10 (D)

9.20E-15

-2.63E-14

-5.04E-12

-1.87E-11

-7.77E-13

-9.52E-13

-2.47E-18

Coefficient of order 12 (E)

1.19E-17

2.19E-17

-1.12E-23

6.19E-25

1.16E-24

-2.01E-24

1.12E-21

Table 3: thickness variable meter

	80 inch (u-shaped)	100 inch (U)	120 cun (120 cun)
				D1	389	488	585
D2	-13.117	-12.817	-12.5968
				D3	-10	-10.28	-10.48
D4	-6.83	-6.85	6.87

Example 3:

according to the utility model discloses embodiment 1's optical lens's for projection application example.

As shown in fig. 2, in the present application example;

the reflecting surface of the concave reflecting mirror 1 is an aspheric surface;

the first lens group includes a first aspherical lens G1, f₁∈[-35mm,-25mm]。

The second lens group includes:

lenses G2-G5 having negative, positive, and negative powers respectively disposed in order from the object side to the image side in the optical axis direction, wherein the lens G5 adjacent to the stop is a third aspherical lens;

the third lens group includes:

lenses G6-G13 having, in order from the object side to the image side in the optical axis direction, powers of negative, positive, negative, and positive, respectively, wherein: a lens G13 adjacent to the galvanometer is a second aspheric lens, lenses G6-G7 are cemented lens groups, lenses G8-G10 are triple cemented lens groups, and lenses G11-G12 are double cemented lens groups;

table 4: and (5) lens structure parameters.

Table 5: parameters of each aspherical lens

Table 6: thickness variable meter

Example 4:

according to the utility model discloses embodiment 1's optical lens's for projection application example.

As shown in fig. 3, in the present application example;

the reflecting surface of the concave reflecting mirror 1 is an aspheric surface;

the first lens group includes a first aspherical lens G1, f₁∈[-35mm,-25mm]。

The second lens group includes:

lenses G2-G5 having negative, positive, and negative powers respectively disposed in order from the object side to the image side in the optical axis direction, wherein the lens G5 adjacent to the stop is a third aspherical lens;

the third lens group includes:

lenses G6-G12 having, in order from the object side to the image side in the optical axis direction, powers of positive, negative, positive, and positive, respectively, wherein: the lens G12 adjacent to the galvanometer is a second aspheric lens, the lenses G7-G9 are triple cemented lens groups, and the lenses G9-G10 are double cemented lens groups;

table 7: and (5) lens structure parameters.

Table 8: each aspheric lens parameter.

Table 9: thickness variation table.

	80 inch (u-shaped)	100 inch (U)	120 cun (120 cun)
				D1	389	488	585
D2	-13.6645	-13.3951	-13.2145
				D3	-17.71	-17.9494	-18.13
D4	-6.8	-6.83	-6.85

Claims (9)

1. An optical lens for projection, characterized in that: the optical lens for projection includes:

the projection optical lens comprises a concave reflecting mirror, a first lens group, a second lens group, a third lens group and a galvanometer, wherein the concave reflecting mirror, the first lens group, the second lens group, the third lens group and the galvanometer are arranged in sequence from an object side to an image side; the third lens group comprises at least two lenses, and a diaphragm is arranged between the lenses of the third lens group;

the relative aperture FNo of the optical lens for projection satisfies: FNo is belonged to [1.8,2.2 ];

focal length f of the second lens group₂And the focal length f of the optical lens for projection satisfies:

2. an optical lens for projection as set forth in claim 1, wherein: the first lens group comprises at least one first aspheric lens, and a cross-sectional contour line of at least one side surface of the first aspheric lens on one reference surface where the optical axis is located comprises a first section located in the middle and two second sections located on two sides of the first section respectively; the center of curvature of each point of the first segment is located on one side of the cross-sectional contour line, and the center of curvature of each point of the second segment is located on the other side of the cross-sectional contour line.

3. An optical lens for projection as set forth in claim 1, wherein: the third lens group includes:

the three-cemented lens group comprises three lenses with negative, positive and negative focal powers which are sequentially arranged; focal length f of triple cemented lens group_3-0-3Satisfies the following conditions:

two cemented lens groups including two lenses with positive and negative focal powers arranged in sequence, and focal length f of the two cemented lens groups_3-0-2And focal length f of triple cemented lens group_3-0-3Satisfies the following conditions:

4. an optical lens for projection as set forth in claim 3, wherein: and light sequentially passes through the diaphragm, the three cemented lens group and the two cemented lens group.

5. An optical lens for projection as set forth in claim 1, wherein: the second lens group includes at least two lenses.

6. An optical lens for projection as set forth in claim 1, wherein: the lens of the third lens group adjacent to the galvanometer is a second aspheric lens and meets the following conditions:

f_3-0-1d is the distance from the second aspheric lens to the galvanometer.

7. An optical lens for projection as set forth in claim 1, wherein: the lens of the second lens group adjacent to the diaphragm is a third aspheric lens, and the two aspheric transmission surfaces meet the following conditions:

R_2-0-1is the radius of curvature, R, of the first transmission surface of the third aspheric lens_2-0-2Is the radius of curvature, K, of the second transmission surface of the third aspheric lens_2-0-1Is the value of K, of the first transmission surface_2-0-2Is the K value of the second transmission surface.

8. An optical lens for projection as set forth in claim 1, wherein: the lens adjacent to the first lens group in the second lens group is a first lens, and the first lens satisfies the following conditions:

1.9≤N_d2≤2，15≤V_d2≤25；N_d2is the refractive index, V, of the first lens_d2Is the abbe number of the first lens.

9. An optical lens for projection as set forth in claim 1, wherein: focal length of the first lens groupf₁Focal length f of the third lens group₃Satisfies the following conditions:

Images