CN116661114A

CN116661114A - Zoom projection lens

Info

Publication number: CN116661114A
Application number: CN202210714026.7A
Authority: CN
Inventors: 赵哲; 陈怡学
Original assignee: Yibin Jimi Photoelectric Co Ltd
Current assignee: Yibin Jimi Photoelectric Co Ltd
Priority date: 2022-06-22
Filing date: 2022-06-22
Publication date: 2023-08-29

Abstract

The invention discloses a zoom projection lens, which comprises a focusing lens group, a first zooming group, a second zooming group, a third zooming group and a fixed lens group, wherein the focusing lens group, the first zooming group, the second zooming group, the third zooming group and the fixed lens group are sequentially arranged from an enlarging side to a reducing side, the focal power of the fixed lens group is positive and comprises one lens, the first zooming group comprises one lens, the third zooming group comprises a diaphragm and five lenses positioned on the reducing side of the diaphragm, the first zooming group, the second zooming group and the third zooming group are combined to form a zooming lens group with positive focal power, the first zooming group, the second zooming group and the third zooming group move along an optical axis in the same direction and are respectively independent to zoom, and the focal power of the focusing lens group is negative and comprises a first lens, a second lens and a third lens which are sequentially arranged from the enlarging side to the reducing side. The invention reduces the relative aperture diaphragm number, realizes the large aperture diaphragm, improves the brightness of the picture, improves the chromatic aberration, inhibits the system distortion and improves the projection image quality.

Description

Zoom projection lens

Technical Field

The present disclosure relates to optical lenses, and particularly to a zoom projection lens.

Background

With the development of projection markets, the requirements of users on the use of products are higher and higher, and the main stream requirements are high in brightness, portability and excellent in performance. Projectors that obtain pictures of different projection sizes by means of continuous zooming at a fixed projection distance are particularly popular with the market and the vast consumer. The FNO of the existing zoom projection lens is large, the aperture of the diaphragm is small, so that the brightness of a picture is low, the distortion is large, the quality of the projected picture is influenced, and the viewing experience is influenced.

Disclosure of Invention

The invention aims to solve the technical problems and the technical task of improving the prior art, provides a zoom projection lens, and solves the problems of small aperture, low projection brightness, large distortion and poor projection picture quality of the zoom projection lens in the prior art.

In order to solve the technical problems, the technical scheme of the invention is as follows:

the zoom projection lens comprises a focusing lens group, a first zooming group, a second zooming group, a third zooming group and a fixed lens group which are sequentially arranged from an enlarging side to a reducing side, wherein the focal power of the fixed lens group is positive and the fixed lens group comprises one lens, the first zooming group comprises one lens, the second zooming group comprises one lens, the third zooming group comprises a diaphragm and five lenses positioned at the reducing side of the diaphragm, the first zooming group, the second zooming group and the third zooming group are combined to form a zooming lens group with positive focal power, the first zooming group, the second zooming group and the third zooming group move along an optical axis in the same direction and are independent respectively so as to zoom, and the focusing lens group has negative focal power and comprises a first lens with negative refractive power, a second lens with negative refractive power and a third lens with positive refractive power which are sequentially arranged from the enlarging side to the reducing side; the relative aperture F-number FNOw at the wide-angle end is less than or equal to 1.7, and the relative aperture F-number FNOt at the telescopic end is less than or equal to 1.85.

The zoom projection lens has the advantages of simple and compact structure, small quantity of lenses, small occupied volume, reduction of the relative aperture diaphragm number, realization of large-caliber diaphragm, improvement of picture brightness, effective improvement of chromatic aberration, suppression of system distortion, improvement of projection image quality and improvement of viewing experience.

Further, the first lens is a meniscus aspheric negative lens protruding to the magnifying side, the second lens is a biconcave negative lens, and the third lens is a biconvex positive lens. The curvature radius and thickness of each lens of the focusing lens group are adjusted while the number of lenses is reduced, the first lens is an aspheric lens, off-axis aberration and distortion can be effectively corrected, field curvature can be effectively corrected, the incidence angle of large-angle light rays is gentle, more light rays enter the system after being converged, the third lens is similar to a plano-convex lens, negative distortion is generated, and positive distortion can be corrected.

Further, the third zoom group comprises a tenth lens closest to the reduction side, the tenth lens is an aspheric lens with positive diopter, the curvature radius of the reduction side surface of the first lens is 5-30 mm, the curvature radius of the reduction side surface of the tenth lens is-200-5 mm, and the zoom ratio of the zoom projection lens is 1.25 EFLt/EFLw less than or equal to 1.5. The relative aperture f-number of the zoom projection lens is reduced compared with that of the zoom projection lens with the traditional architecture, the design difficulty is increased, and the zoom ratio meets the design requirement through the collocation of the curvature radius of the first lens shrinkage side surface and the curvature radius of the tenth lens shrinkage side surface.

Further, the third zoom group comprises a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens which are sequentially arranged from the enlarging side to the reducing side, diopters of the sixth lens, the seventh lens and the eighth lens are sequentially positive, negative and positive, the diopters of the sixth lens, the seventh lens and the eighth lens are sequentially glued and connected into a three-gluing lens with positive diopter, the ninth lens is a biconcave negative lens, and the tenth lens is a lens with positive diopter. The three-cemented lens can effectively eliminate chromatic aberration and correct system spherical aberration.

Further, the refractive index of the sixth lens and the eighth lens is lower than that of the seventh lens, and the abbe numbers of the sixth lens and the eighth lens are higher than that of the seventh lens, so that system chromatic aberration and spherical aberration can be effectively corrected.

Further, the first zoom group includes a fourth lens which is a positive meniscus lens convex to the magnification side, the second zoom group includes a fifth lens which is a biconvex positive lens; the fixed lens group includes an eleventh lens that is a biconvex positive lens. The fifth lens is positioned on the amplifying side of the diaphragm, and the aperture of the diaphragm is reduced and the outer diameter volume of the zoom projection lens is reduced by utilizing the effective converging light of the fifth lens.

Further, the total long focal length ratio TTLw/EFLw of the lens is less than or equal to 10.76, and BFL/EFLw is more than 1.78; the telecentric angle TAw at the wide angle end is less than or equal to 1.4 degrees, and the telecentric angle TAt at the telescopic end is less than or equal to 0.2 degrees, so that the large aperture and high brightness performance are realized.

Further, the positions of the focusing lens group and the fixed lens group are unchanged in the zooming process, and the positions of the imaging surface are unchanged. The imaging plane position is always kept unchanged in the zooming process, the size of the projection picture is adjusted under the condition that the imaging plane position is unchanged, the projection picture is ensured to be always clear, and focusing action is not needed.

Compared with the prior art, the invention has the advantages that:

the zoom projection lens effectively improves chromatic aberration and suppresses system distortion, has the characteristics of large aperture, high brightness, low distortion, high performance, continuous zooming and the like, has good imaging quality, simple and compact structure, small number of lenses, small occupied volume, high mass productivity and convenient mass production.

Drawings

FIG. 1 is a schematic view of a zoom projection lens of the present invention at the wide-angle end;

fig. 2 is a schematic view of the zoom projection lens at the telephoto end according to the present invention.

In the figure:

a focusing lens group C1, a first zoom group C2, a second zoom group C3, a third zoom group C4, a fixed lens group C5, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a diaphragm 10, a galvanometer 11, and a DMD chip 12.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The zoom projection lens disclosed by the embodiment of the invention effectively inhibits distortion, improves the chromatic aberration of a projection system, and has the advantages of compact structure, small occupied space, light weight, low cost, large aperture and good imaging quality.

As shown in fig. 1, a zoom projection lens mainly includes a focus lens group C1, a first zoom group C2, a second zoom group C3, a third zoom group C4, and a fixed lens group C5, which are sequentially arranged from an enlargement side to a reduction side;

the focal lens group C1 has negative focal power and comprises a first lens L1, a second lens L2 and a third lens L3 which are sequentially arranged from an amplifying side to a reducing side, wherein the first lens L1 is a meniscus aspheric negative lens protruding to the amplifying side, the even aspheric surface of the first lens L1 bears the light receiving function of large-field light, increases light passing, corrects distortion and astigmatism and corrects field curvature, the second lens L2 is a biconcave negative lens, and the third lens L3 is a biconvex positive lens;

the first zoom group C2 includes a fourth lens L4, the fourth lens L4 being a positive meniscus lens convex to the magnification side;

the second zoom group C3 includes a fifth lens L5, the fifth lens L5 being a biconvex positive lens;

the third zoom group C4 comprises a diaphragm 10 and five lenses positioned on the reduction side of the diaphragm 10, wherein the five lenses are specifically a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9 and a tenth lens L10 which are sequentially arranged from the enlargement side to the reduction side, diopters of the sixth lens L6, the seventh lens L7 and the eighth lens L8 are sequentially positive, negative and positive, and three lenses are connected into a three-cemented lens with positive diopter in a cemented mode, the ninth lens L9 is a biconcave negative lens, the tenth lens L10 is an aspheric lens with positive diopter, and the enlargement side surface and the reduction side surface of the tenth lens L10 are respectively an even aspheric surface;

the refractive index of the sixth lens L6 and the eighth lens L8 is lower than that of the seventh lens L7, the abbe numbers of the sixth lens L6 and the eighth lens L8 are higher than that of the seventh lens L7, and the sixth lens L6 and the eighth lens L8 are respectively made of different low-dispersion materials, specifically a material with the abbe number greater than 65, and the refractive index, the abbe number collocation and the lens shape optimization are carried out according to application wave bands, so that chromatic aberration and spherical aberration are well corrected;

the first zoom group C2, the second zoom group C3 and the third zoom group C4 are combined to form a zoom lens group with positive focal power, the first zoom group C2, the second zoom group C3 and the third zoom group C4 move along the optical axis in the same direction and are independent to each other so as to perform zooming, specifically, when zooming is performed from the wide-angle end to the telescopic end, the first zoom group C2, the second zoom group C3 and the third zoom group C4 move towards the amplifying side, the positions of the focusing lens group C1 and the fixed lens group C5 are unchanged in the zooming process, the position of the imaging surface is unchanged, and the projection picture can be maintained to be always clear without adjusting the focusing lens group C1;

the focal power of the fixed lens group C5 is positive, the fixed lens group C5 is specifically provided with only an eleventh lens L11, and the eleventh lens L11 is a biconvex positive lens;

the projection system using the zoom projection lens further includes a galvanometer 11, an equivalent prism, and a DMD chip 12 sequentially provided on the reduction side of the eleventh lens L11, and by providing the galvanometer 11, the projection lens can simultaneously obtain the resolution inherent to the size of the DMD chip 12 when the galvanometer 11 is stationary and the 4K high resolution when the galvanometer 11 is operating to shake.

Specifically, an adjustable air gap is formed between the shrinking side of the third lens L3 and the enlarging side of the fourth lens L4 during zooming; an adjustable air gap is formed between the shrinking side of the fourth lens L4 and the enlarging side of the fifth lens L5 during zooming; an adjustable air gap is formed between the reducing side of the fifth lens L5 and the amplifying side of the diaphragm 10 during zooming, the third lens L3 is approximately a plano-convex lens and the fifth lens L5 generate negative distortion, the positive distortion of the front group can be corrected, the fifth lens L5 is arranged on the amplifying side of the diaphragm 10, light rays are effectively converged, the aperture of the opening of the diaphragm 10 is reduced, and a projection lens with small outer diameter and volume is obtained; an air gap adjustable in zooming is provided between the reduction side of the tenth lens L10 and the enlargement side of the eleventh lens L11.

The relative aperture f-number of the zoom projection lens is reduced, the relative aperture f-number FNOw at the wide-angle end is less than or equal to 1.7, the relative aperture f-number FNOt at the telephoto end is less than or equal to 1.85, the design difficulty is increased, the zoom ratio is lower than that of the traditional architecture, the zoom ratio meets the design requirement through the collocation of the curvature radius of the reduced side surface of the first lens L1 and the curvature radius of the reduced side surface of the tenth lens L10, specifically, the curvature radius of the reduced side surface of the first lens L1 is 5-30 mm, preferably 8-16 mm, the curvature radius of the reduced side surface of the tenth lens L10 is-200 to-5 mm, preferably-40 to-20 mm, and the zoom ratio of the zoom projection lens is 1.25 EFLt/EFLw is less than or equal to 1.5;

the total long focal length ratio TTLw/EFLw of the lens is less than or equal to 10.76, and BFL/EFLw is more than 1.78; the telecentric angle TAw at the wide angle end is less than or equal to 1.4 degrees, the telecentric angle TAt at the telephoto end is less than or equal to 0.2 degrees, wherein EFLt is an effective focal length at the telephoto end, EFLw is an effective focal length at the wide angle end, TTLw is a total lens length at the wide angle end, the total lens length can be defined as a distance from the top point of the amplifying side surface of the first lens L1 to the image plane of the DMD chip 12, BFL is an optical back focal length, and the distance from the last surface of the lens in the projection lens to the image plane.

The design parameters of the projection system are shown in Table 1, where R in Table 1 represents the radius of curvature and Dn represents the thickness of the lenses or the air spacing between the lenses;

TABLE 1

The first lens L1 and the tenth lens L10 are aspheric lenses, and the rest lenses are spherical lenses, and the aspheric polynomial formula is as follows:

in the formula, z represents the distance vector height from the aspheric surface fixed point when the aspheric surface is at the position of the height r along the optical axis direction, the parameter c is the curvature corresponding to the radius, r is the radial height of the lens, k is the Conic Constant, and α1 to α8 are aspheric coefficients corresponding to the twenty-sixteen steps, respectively, as shown in table 2.

TABLE 2

K

α2

α3

α4

α5

α6

α7

α8

S1

0

-1.5E-04

7.6E-07

-3.2E-09

1.0E-11

-2.3E-14

3.5E-17

-2.8E-20

S2

-0.7403

-2.3E-04

1.2E-06

-8.3E-09

5.7E-11

-3.5E-13

1.2E-15

-1.9E-18

S20

0

-1.9E-05

7.5E-08

-1.9E-11

-3.1E-11

4.5E-13

-2.1E-15

0.0E+00

S21

0

-4.6E-06

-7.0E-08

2.9E-09

-5.9E-11

5.2E-13

-1.8E-15

0.0E+00

Table 3 shows the intervals d1 to d4 in table 1 corresponding to the zoom projection lens of the present embodiment at the wide-angle end and the telephoto end, respectively:

TABLE 3 Table 3

Interval (mm)	d1	d2	d3	d4
					Wide angle end	12.1	9.4	16.7	5.9
Telescope end	5.6	4.3	21.4	12.7

That is, at the wide-angle end as shown in fig. 1, the interval between the third lens L3 of the focus lens group C1 and the fourth lens L4 of the first zoom group C2 is 12.1mm, the interval between the fourth lens L4 of the first zoom group C2 and the fifth lens L5 of the second zoom group C3 is 9.4mm, the interval between the fifth lens L5 of the second zoom group C3 and the diaphragm 10 of the third zoom group C4 is 16.7mm, and the interval between the tenth lens L10 of the third zoom group C4 and the eleventh lens L11 of the fixed lens group C5 is 5.9mm;

at the telephoto end as shown in fig. 2, the distance between the third lens L3 of the focusing lens group C1 and the fourth lens L4 of the first zooming group C2 is 5.6mm, the distance between the fourth lens L4 of the first zooming group C2 and the fifth lens L5 of the second zooming group C3 is 4.3mm, the distance between the fifth lens L5 of the second zooming group C3 and the diaphragm 10 of the third zooming group C4 is 21.4mm, and the distance between the tenth lens L10 of the third zooming group C4 and the eleventh lens L11 of the fixed lens group C5 is 12.7mm.

The zoom projection lens is matched with a DMD of 0.47 inch, the physical resolution of the DMD chip 12 is 93lp/mm, and a picture of 76.2cm (30 inches) to 228.6cm (200 inches) can be projected at a working distance of 2390 mm.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that the above-mentioned preferred embodiment should not be construed as limiting the invention, and the scope of the invention should be defined by the appended claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and such modifications and adaptations are intended to be comprehended within the scope of the invention.

Claims

1. The zoom projection lens is characterized by comprising a focusing lens group, a first zooming group, a second zooming group, a third zooming group and a fixed lens group which are sequentially arranged from an amplifying side to a reducing side, wherein the focal power of the fixed lens group is positive and the fixed lens group comprises one lens, the first zooming group comprises one lens, the second zooming group comprises one lens, the third zooming group comprises a diaphragm and five lenses positioned on the reducing side of the diaphragm, the first zooming group, the second zooming group and the third zooming group are combined to form a zooming lens group with positive focal power, the first zooming group, the second zooming group and the third zooming group move along an optical axis in the same direction and are respectively independent to perform zooming, and the focal power of the focusing lens group is negative and comprises a first lens with negative diopter, a second lens with negative diopter and a third lens with positive diopter which are sequentially arranged from the amplifying side to the reducing side;

the relative aperture F-number FNOw at the wide-angle end is less than or equal to 1.7, and the relative aperture F-number FNOt at the telescopic end is less than or equal to 1.85.

2. The zoom projection lens of claim 1 wherein the first lens is a meniscus aspheric negative lens convex to the magnification side, the second lens is a biconcave negative lens, and the third lens is a biconvex positive lens.

3. The zoom projection lens according to claim 1, wherein the third zoom group includes a tenth lens closest to the reduction side, the tenth lens being an aspherical lens having positive refractive power, a radius of curvature of a reduction side surface of the first lens being 5 to 30mm, a radius of curvature of a reduction side surface of the tenth lens being-200 to-5 mm, and a zoom ratio of the zoom projection lens being 1.25.ltoreq.EFLt/EFLw.ltoreq.1.5.

4. The zoom projection lens according to claim 1, wherein the third zoom group further comprises a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens which are sequentially arranged from the enlargement side to the reduction side, diopters of the sixth lens, the seventh lens and the eighth lens are sequentially positive, negative, positive and three are bonded to form a three-cemented lens with positive diopter, the ninth lens is a biconcave negative lens, and the tenth lens is a lens with positive diopter.

5. The zoom projection lens of claim 4 wherein the refractive index of the sixth and eighth lenses is lower than the refractive index of the seventh lens, the abbe number of the sixth and eighth lenses being higher than the abbe number of the seventh lens.

6. The zoom projection lens of claim 1 wherein the first zoom group comprises a fourth lens which is a positive meniscus lens convex to the magnification side, the second zoom group comprises a fifth lens which is a biconvex positive lens; the fixed lens group includes an eleventh lens that is a biconvex positive lens.

7. The zoom projection lens of any one of claims 1 to 6 wherein the total lens length to focal length ratio TTLw/EFLw is less than or equal to 10.76, bfl/EFLw >1.78; the telecentric angle TAw at the wide angle end is less than or equal to 1.4 degrees, and the telecentric angle TAt at the telescope end is less than or equal to 0.2 degrees.

8. The zoom projection lens of any one of claims 1 to 6 wherein the focus lens group and fixed lens group positions are unchanged during zooming and the position of the imaging plane is unchanged.