Wide-angle projection lens

Abstract

The invention discloses a wide-angle projection lens. The wide-angle projection lens comprises a first lens group, a second lens group and a third lens group, wherein the first lens group comprises at least one meniscus aspherical lens, and the meniscus aspherical lens is used for eliminating distortion aberration; the second lens group comprises at least one movable lens and is used for obtaining clear pictures under different projection distances by moving the at least one movable lens; and the third lens group comprises at least one group of glued lenses and is used for eliminating chromatic aberration. The wide-angle projection lens provided by the invention is simple and reasonable in structure, can obtain clear pictures in a large range through the cooperation of the lens groups, is high in imaging quality, is small in picture distortion, and can be matched with a high-lumen projection machine. The field angle of the projection lens is increased, high projection quality of the projection lens is ensured, and the projection lens is worthy of large-area popularization and application.

Description

Technical Field

[0001] The present invention relates to the technical field of projection equipment, and in particular to a wide-angle projection lens capable of focusing in a large range. Background Art

[0002] A projector, also known as a projector, is a device that can project images or videos onto a screen. It can be connected to computers, VCDs, DVDs, BDs, game consoles, DVs, etc. through different interfaces to play corresponding video signals. Projectors are widely used in homes, offices, schools, and entertainment venues.

[0003] With the development of semiconductor technology, image display products are becoming more and more diversified, which has led to an increasing demand for projectors. At the same time, the competition in the engineering projection market is becoming increasingly fierce, and the booming development of outdoor landscape, exhibition display, cultural tourism and other fields has put forward higher requirements for engineering projection products.

[0004] Traditional high-lumen engineering projectors mainly use medium- and long-focus projection lenses, which can hardly meet the projection needs of different venues, such as projecting images in narrow spaces, or projecting extra-large images at concerts and large conferences.

[0005] Therefore, how to further increase the field of view of the projection lens to ensure high projection quality is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the invention

[0006] The present invention provides a wide-angle projection lens. Through the cooperation between lens groups, a clear picture can be obtained in a wide range, and at the same time, the imaging quality is high, the picture distortion is small, and it can match a high-lumen projection machine.

[0007] The present invention provides the following scheme:

[0008] A wide-angle projection lens, comprising:

[0009] a first lens group, a second lens group, and a third lens group;

[0010] Wherein, the first lens group includes at least one meniscus aspherical lens for eliminating distortion aberration;

[0011] The second lens group includes at least one movable lens, and is used to obtain a clear picture at different projection distances by moving at least one movable lens;

[0012] The third lens group includes at least one group of cemented lenses for eliminating chromatic aberration.

[0013] Preferably, the focal length f of the entire optical system of the wide-angle projection lens and the equivalent air back focus BFL of the entire optical system satisfy the following relationship: 0.1 <f / BFL<0.3。

[0014] Preferably, the focal length f1 of the first lens group and the focal length f of the entire optical system satisfy the following relationship: -0.6 <f / f1<-0.3。

[0015] Preferably, the focal length f2 of the second lens group and the focal length f of the entire optical system satisfy the following relationship: 0.1 <f / f2<0.3。

[0016] Preferably, the focal length f2 of the second lens group and the focal length f3 of the third lens group satisfy the following relationship: 0.4 <f3 / f2<0.8。

[0017] Preferably, the Abbe number of at least one of the meniscus aspherical lenses is between 40 and 60.

[0018] Preferably: the first lens group includes a first lens, a second lens and a third lens; the first lens is a meniscus type negative power lens, the second lens is a meniscus type negative power lens, and the third lens is a meniscus type negative power aspherical lens.

[0019] Preferably: the second lens group includes a fourth lens, a fifth lens, a sixth lens and a seventh lens; the fourth lens with a biconvex positive focal power and the fifth lens with a meniscus negative focal power form a first cemented lens, and by moving the first cemented lens, a clear picture can be obtained at different projection distances; the sixth lens is a biconcave negative focal power lens, and the seventh lens is a biconvex positive focal power lens.

[0020] Preferably: the third lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens; the eighth lens of biconcave negative power and the ninth lens of biconvex positive power form a second cemented lens, the tenth lens of biconvex positive power and the eleventh lens of meniscus negative power form a third cemented lens, the twelfth lens is a meniscus positive power lens, and the thirteenth lens is a biconvex positive power lens.

[0021] Preferably, the optical distortion Distortion of the entire optical system of the wide-angle projection lens satisfies the following relationship: 0%<|Distortion|<5%; the maximum field of view FOV of the entire optical system of the wide-angle projection lens satisfies the following relationship: 80° <FOV<100°。

[0022] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0023] Through the present invention, a wide-angle projection lens can be realized. In one implementation, the lens may include a first lens group, a second lens group and a third lens group; wherein the first lens group includes at least one meniscus aspherical lens for eliminating distortion aberration; the second lens group includes at least one movable lens for obtaining a clear picture at different projection distances by moving at least one movable lens; the third lens group includes at least one group of cemented lenses for eliminating chromatic aberration. The wide-angle projection lens provided by the present application has a simple and reasonable structure. Through the coordination between the lens groups, a clear picture can be obtained in a large range. At the same time, the imaging quality is high, the picture distortion is small, and it can match a high-lumen projection machine. The field of view of the projection lens is increased, which ensures that it has high projection quality and is worthy of large-scale promotion and use.

[0024] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 is a schematic structural diagram of a wide-angle projection lens provided by an embodiment of the present invention;

[0027] Figure 2 1 is a schematic diagram of MTF of a wide-angle projection lens capable of focusing in a wide range provided by an embodiment of the present invention, with a focal length of 10 mm, a maximum field of view of 90°, and a projection distance of 4.5 m.

[0028] Figure 3 1 is a schematic diagram of MTF of a wide-angle projection lens capable of focusing in a wide range provided by an embodiment of the present invention, with a focal length of 10 mm, a maximum field of view of 90°, and a projection distance of 2 m.

[0029] Figure 4 1 is a schematic diagram of MTF of a wide-angle projection lens capable of focusing in a wide range provided by an embodiment of the present invention, with a focal length of 10 mm, a maximum field of view of 90°, and a projection distance of 10 m. DETAILED DESCRIPTION

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0031] Embodiment

[0032] Refer to Figure 1 , a wide-angle projection lens provided by an embodiment of the present invention, as Figure 1 shown, the lens sequentially includes, from the object side to the image side along its optical axis direction:

[0033] The first lens (L1) group (G1), the second lens (L2) group (G2), and the third lens (L3) group (G3);

[0034] Among them, the first lens (L1) group (G1) includes at least one meniscus aspheric lens for eliminating distortion aberration; specifically, the focal length f1 of the first lens (L1) group (G1) and the focal length f of the entire optical system satisfy the following relationship: -0.6 < f / f1 < -0.3. The Abbe number of at least one of the meniscus aspheric lenses is between 40 and 60.

[0035] Specifically, the first lens (L1) group (G1) includes a first lens (L1), a second lens (L2), and a third lens (L3); the first lens (L1) is a meniscus negative power lens, the second lens (L2) is a meniscus negative power lens, and the third lens (L3) is a meniscus negative power aspheric lens.

[0036] The second lens (L2) group (G2) includes at least one movable lens for obtaining a clear image at different projection distances by moving at least one of the movable lenses; specifically, the focal length f2 of the second lens (L2) group (G2) and the focal length f of the entire optical system satisfy the following relationship: 0.1 < f / f2 < 0.3.

[0037] Specifically, the second lens (L2) group (G2) includes a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), and a seventh lens (L7); the fourth lens (L4) with a biconvex positive power and the fifth lens (L5) with a meniscus negative power form a first cemented lens, and a clear image can be obtained at different projection distances by moving the first cemented lens; the sixth lens (L6) is a biconcave negative power lens, and the seventh lens (L7) is a biconvex positive power lens.

[0038] The third lens group (L3) (G3) includes at least one group of cemented lenses for eliminating chromatic aberration. Specifically, the focal length f2 of the second lens group (L2) (G2) and the focal length f3 of the third lens group (L3) (G3) satisfy the following relationship: 0.4 <f3 / f2<0.8。

[0039] In a specific implementation, the third lens (L3) group (G3) includes an eighth lens (L8), a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11), a twelfth lens (L12) and a thirteenth lens (L13); the eighth lens (L8) of biconcave negative power and the ninth lens (L9) of biconvex positive power form a second cemented lens, the tenth lens (L10) of biconvex positive power and the eleventh lens (L11) of meniscus negative power form a third cemented lens, the twelfth lens (L12) is a meniscus positive power lens, and the thirteenth lens (L13) is a biconvex positive power lens.

[0040] Furthermore, the focal length f of the entire optical system of the wide-angle projection lens and the equivalent air back focus BFL of the entire optical system satisfy the following relationship: 0.1 <f / BFL<0.3。

[0041] The optical distortion Distortion of the entire optical system of the wide-angle projection lens satisfies the following relationship: 0%<|Distortion|<5%; the maximum field of view FOV of the entire optical system of the wide-angle projection lens satisfies the following relationship: 80° <FOV<100°。

[0042] The wide-angle projection lens provided in the embodiment of the present application comprises a first lens group (G1), a second lens group (G2) and a third lens group (G3), wherein the first lens group (G1) comprises at least one meniscus aspherical lens, which functions to eliminate distortion aberration; the second lens group (G2) comprises at least one movable lens, and by moving at least one lens, a clear image can be obtained at different projection distances; the third lens group (G3) comprises at least one group of cemented lenses, which functions to eliminate chromatic aberration.

[0043] The first lens group (G1) includes a first lens (L1), a second lens (L2) and a third lens (L3), wherein the first lens (L1) is a meniscus type negative power lens, the second lens (L2) is a meniscus type negative power lens, and the third lens (L3) is a meniscus type negative power aspherical lens, and the Abbe number thereof is between 40 and 60.

[0044] The second lens group (G2) includes a fourth lens (L4), a fifth lens (L5), a sixth lens (L6) and a seventh lens (L7), wherein the fourth lens (L4) with a biconvex positive power and the fifth lens (L5) with a meniscus negative power form a cemented lens. By moving the cemented lens, a clear image can be obtained at different projection distances. The sixth lens (L6) is a biconcave negative power lens, and the seventh lens (L7) is a biconvex positive power lens.

[0045] The third lens group (G3) includes an eighth lens (L8), a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11), a twelfth lens (L12) and a thirteenth lens (L13), wherein the eighth lens (L8) of biconcave negative power and the ninth lens (L9) of biconvex positive power form a cemented lens, the tenth lens (L10) of biconvex positive power and the eleventh lens (L11) of meniscus negative power form a cemented lens, the twelfth lens (L12) is a meniscus positive power lens, and the thirteenth lens (L13) is a biconvex positive power lens.

[0046] The performance of the wide-angle projection lens provided by the embodiment of the present application is verified below by taking an optical system with a focal length of 10 mm and a maximum field of view of 90° as an example. The entire wide-angle projection lens includes 13 lenses in total, and the optical data statistics of each lens are shown in Table 1.

[0047] Table 1

[0048]

[0049]

[0050] Among them, R represents the radius of curvature of the lens, d represents the lens thickness or air space, nd represents the refractive index of the glass, and vd represents the Abbe number of the glass.

[0051] All aspheric surfaces are even aspheric surfaces, and their expressions are as follows:

[0052]

[0053] Among them, z is the aspheric surface vertex height when the aspheric surface is at a height of r along the optical axis, c represents the vertex curvature of the surface, k is the conic coefficient of the aspheric surface, and α2, α3, α4, α5, α6, α7, and α8 are high-order aspheric surface coefficients. The details are shown in Table 2.

[0054] Table 2

[0055]

[0056] The verified results show that the whole system has a high resolution, see Figure 2At the same time, the entire system can obtain clear images from 2m to 10m, see Figure 3 and Figure 4 .

[0057] In summary, the wide-angle projection lens provided by the present application has a simple and reasonable structure. Through the cooperation between the lens groups, a clear picture can be obtained in a large range. At the same time, the imaging quality is high, the picture distortion is small, and it can match a high-lumen projection machine. The field of view of the projection lens is increased, and its high projection quality is guaranteed, which is worthy of large-scale promotion and use.

[0058] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A wide-angle projection lens, characterized in that: Along the optical axis from the object side to the image side, it includes: a first lens group, a second lens group, and a third lens group; Wherein, the first lens group includes at least one meniscus aspherical lens for eliminating distortion aberration; The second lens group includes at least one movable lens, and is used to obtain a clear picture at different projection distances by moving at least one movable lens; The third lens group includes at least one group of cemented lenses for eliminating chromatic aberration.

2. The wide-angle projection lens according to claim 1, characterized in that: The focal length f of the entire optical system of the wide-angle projection lens and the equivalent air back focus BFL of the entire optical system satisfy the following relationship: <f / BFL<0.3。 3. The wide-angle projection lens according to claim 1, characterized in that: The focal length f1 of the first lens group and the focal length f of the entire optical system satisfy the following relationship: -0.6 <f / f1<-0.3。 4. The wide-angle projection lens according to claim 1, characterized in that: The focal length f2 of the second lens group and the focal length f of the entire optical system satisfy the following relationship: 0.1 <f / f2<0.3。 5. The wide-angle projection lens according to claim 1, characterized in that: The focal length f2 of the second lens group and the focal length f3 of the third lens group satisfy the following relationship: 0.4 <f3 / f2<0.8。 6. The wide-angle projection lens according to claim 1, characterized in that: The Abbe number of at least one of the meniscus aspherical lenses is between 40 and 60.

7. The wide-angle projection lens according to claim 6, characterized in that: The first lens group includes a first lens, a second lens and a third lens; the first lens is a meniscus type negative power lens, the second lens is a meniscus type negative power lens, and the third lens is a meniscus type negative power aspherical lens.

8. The wide-angle projection lens according to claim 1, wherein: The second lens group includes a fourth lens, a fifth lens, a sixth lens and a seventh lens; the fourth lens with a biconvex positive focal power and the fifth lens with a meniscus negative focal power form a first cemented lens, and by moving the first cemented lens, a clear image can be obtained at different projection distances; the sixth lens is a biconcave negative focal power lens, and the seventh lens is a biconvex positive focal power lens.

9. The wide-angle projection lens according to claim 1, characterized in that: The third lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens; the eighth lens with biconcave negative power and the ninth lens with biconvex positive power form a second cemented lens, the tenth lens with biconvex positive power and the eleventh lens with meniscus negative power form a third cemented lens, the twelfth lens is a meniscus positive power lens, and the thirteenth lens is a biconvex positive power lens.

10. The wide-angle projection lens according to claim 1, characterized in that: The optical distortion Distortion of the entire optical system of the wide-angle projection lens satisfies the following relationship: 0%<|Distortion|<5%; the maximum field of view FOV of the entire optical system of the wide-angle projection lens satisfies the following relationship: 80° <FOV<100°。

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