Wide-angle projection lens

Abstract

The application discloses a wide-angle projection lens, which can comprise 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 for eliminating distortion aberration; the second lens group comprises at least one movable lens for obtaining clear pictures at different projection distances by moving the at least one movable lens; and the third lens group comprises at least one set of cemented lenses for eliminating chromatic aberration. The wide-angle projection lens provided by the application has a simple and reasonable structure, can obtain clear pictures in a wide range through cooperation between the lens groups, has high imaging quality, small picture distortion and can match high-lumen projectors. The field of view of the projection lens is increased, the high projection quality is ensured, and the wide-angle projection lens is worthy of large-area popularization and use.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of projection equipment, in particular to a wide-angle projection lens capable of wide-range focusing. BACKGROUND

[0002] A projector, also known as a projection machine, is a device that can project images or videos onto a screen. It can be connected to a computer, VCD, DVD, BD, game console, DV, 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, making the demand for projectors larger and larger. At the same time, the competition in the engineering projection market is becoming increasingly fierce, and the vigorous development of outdoor landscapes, exhibition displays, cultural tourism, etc. puts forward higher requirements for engineering projection products.

[0004] Traditional high-lumen engineering projectors mainly use medium and long focal length projection lenses, which cannot meet the projection needs of different places, such as projecting pictures in narrow spaces or projecting super-large pictures at concerts and large conferences.

[0005] Therefore, how to further increase the field of view of the projection lens and ensure high projection quality is an urgent technical problem for technicians in the field to solve. SUMMARY

[0006] The present application provides a wide-angle projection lens. Through the cooperation between each lens group, clear pictures can be obtained in a wide range, and the imaging quality is high, the picture distortion is small, and it can match high-lumen projection machines.

[0007] The present application provides the following solutions:

[0008] A wide-angle projection lens comprises:

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

[0010] The first lens group comprises at least one meniscus aspherical lens for eliminating distortion aberration;

[0011] The second lens group comprises at least one movable lens for obtaining clear pictures at different projection distances by moving at least one movable lens;

[0012] The third lens group comprises at least one set 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 focal length 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 comprises a first lens, a second lens, and a third lens; the first lens is a meniscus negative power lens, the second lens is a meniscus negative power lens, and the third lens is a meniscus negative power aspherical lens.

[0019] Preferably, the second lens group comprises a fourth lens, a fifth lens, a sixth lens, and a seventh lens; the fourth lens, which is a biconvex positive power lens, and the fifth lens, which is a meniscus negative power lens, 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 power lens, and the seventh lens is a biconvex positive power lens.

[0020] Preferably, the third lens group comprises an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens; the eighth lens, which is a biconcave negative power lens, and the ninth lens, which is a biconvex positive power lens, form a second cemented lens, the tenth lens, which is a biconvex positive power lens, and the eleventh lens, which is a meniscus negative power lens, 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%, and 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 of the present application, the following technical effects are achieved:

[0023] By the present application, a wide-angle projection lens can be realized, in one implementation, the lens can 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 clear picture at different projection distances by moving at least one movable lens; the third lens group includes at least one set of cemented lenses for eliminating chromatic aberration. The wide-angle projection lens provided in the present application has simple and reasonable structure, and through the cooperation between the lens groups, 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 high-lumen projection machines. The field of view of the projection lens is increased, the high projection quality is ensured, and it is worth popularizing and using in a large area.

[0024] Of course, it is not necessary for any product implementing the present application to achieve all the advantages mentioned above at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0025] 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 will be briefly introduced below. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

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

[0027] Figure 2 is an MTF schematic diagram of a wide-angle projection lens provided by an embodiment of the present application, which can be focused in a wide range, the focal length is 10mm, the maximum field of view is 90°, and the projection distance is 4.5m.

[0028] Figure 3 is an MTF schematic diagram of a wide-angle projection lens provided by an embodiment of the present application, which can be focused in a wide range, the focal length is 10mm, the maximum field of view is 90°, and the projection distance is 2m.

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

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0031] Embodiment

[0032] Reference Figure 1 A wide-angle projection lens provided by the embodiment of the present application, as shown in the drawing, sequentially comprises, along the optical axis direction thereof from the object side to the image side: Figure 1

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

[0034] The first lens (L1) group (G1) comprises at least one meniscus aspherical 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 meniscus aspherical lens is between 40 and 60.

[0035] In specific implementation, the first lens (L1) group (G1) comprises 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 aspherical lens.

[0036] The second lens (L2) group (G2) comprises at least one movable lens for obtaining a clear picture at different projection distances by moving at least one movable lens; 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] In specific implementation, the second lens (L2) group (G2) comprises a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), and a seventh lens (L7); the fourth lens (L4) with double-convex positive power and the fifth lens (L5) with meniscus negative power form a first cemented lens, and a clear picture can be obtained at different projection distances by moving the first cemented lens; the sixth lens (L6) is a double-concave negative-power lens, and the seventh lens (L7) is a double-convex positive-power lens.

[0038] ​The third lens (L3) group (G3) includes at least one set of cemented lenses for eliminating chromatic aberration. Specifically, the focal length f2 of the second lens (L2) group (G2) and the focal length f3 of the third lens (L3) group (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) with a double-concave negative focal length and the ninth lens (L9) with a double-convex positive focal length form a second cemented lens, the tenth lens (L10) with a double-convex positive focal length and the eleventh lens (L11) with a meniscus negative focal length form a third cemented lens, the twelfth lens (L12) is a meniscus positive focal length lens, and the thirteenth lens (L13) is a double-convex positive focal length lens.

[0040] Further, the focal length f of the entire optical system of the wide-angle projection lens and the equivalent air back focal length 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%; and 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 embodiments of the present application includes a first lens group (G1), a second lens group (G2), and a third lens group (G3), wherein the first lens group (G1) includes at least one meniscus aspherical lens, which functions to eliminate distortion aberration; the second lens group (G2) includes at least one movable lens, and clear images can be obtained at different projection distances by moving the at least one lens; and the third lens group (G3) includes at least one set 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 negative focal length lens, the second lens (L2) is a meniscus negative focal length lens, and the third lens (L3) is a meniscus negative focal length aspherical lens with an Abbe number between 40 and 60.

[0044] The second lens group (G2) comprises 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 focal length and the fifth lens (L5) with a meniscus negative focal length form a cemented lens, by moving the cemented lens, a clear picture can be obtained at different projection distances, the sixth lens (L6) is a biconcave negative focal length lens, and the seventh lens (L7) is a biconvex positive focal length lens.

[0045] The third lens group (G3) comprises 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) with a biconcave negative focal length and the ninth lens (L9) with a biconvex positive focal length form a cemented lens, the tenth lens (L10) with a biconvex positive focal length and the eleventh lens (L11) with a meniscus negative focal length form a cemented lens, the twelfth lens (L12) is a meniscus positive focal length lens, and the thirteenth lens (L13) is a biconvex positive focal length lens.

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

[0047] Table 1

[0048]

[0049]

[0050] Wherein, R represents the radius of curvature of the lens, d represents the thickness of the lens or the air gap, 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 the expression thereof is as follows:

[0052]

[0053] Wherein, z is the sag of the aspheric surface along the optical axis direction at a height of r, c represents the vertex curvature of the surface, k is the conic coefficient of the aspheric surface, and a2, a3, a4, a5, a6, a7 and a8 are high-order aspheric coefficients. The specific values are shown in Table 2.

[0054] Table 2

[0055]

[0056] The verification result shows that the entire system has a high resolution, and the resolution curve is shown in FIG. 2. Figure 2Meanwhile, the whole system can get clear picture in 2m to 10m, see Figure 3 and Figure 4 .

[0057] In summary, the wide-angle projection lens provided by the application has simple and reasonable structure, can get clear picture in a large range through cooperation between the lens groups, has high imaging quality and small picture distortion, and can match high-lumen projection machines. The field of view of the projection lens is increased, high projection quality is ensured, and the wide-angle projection lens is worth popularization and use.

[0058] It should be noted that, in this text, relational terms such as first and second are used merely to distinguish one entity or action from another, without necessarily requiring or implying any actual such relationship or order between or among the entities or actions. Also, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by an "including a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0059] The above description is merely preferred embodiments of the present application, but not for limiting the protection scope of 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 wide-angle projection lens, characterized in that, The wide-angle projection lens has 13 lenses with optical power. Along its optical axis from the object side to the image side, it includes, in sequence: The first lens group, the second lens group, and the third lens group; The first lens group includes at least one meniscus aspherical lens for eliminating distortion aberrations; the first lens group includes a first lens, a second lens, and a third lens; the first lens is a meniscus negative power lens, the second lens is a meniscus negative power lens, and the third lens is a meniscus negative power aspherical lens. The second lens group includes at least one movable lens for obtaining a clear image at different projection distances by moving at least one of the movable lenses; the second lens group includes a fourth lens, a fifth lens, a sixth lens, and a seventh lens; the fourth lens with biconvex positive power and the fifth lens with 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 is a biconcave negative power lens, and the seventh lens is a biconvex positive power lens; The third lens group includes at least one set of cemented lenses for eliminating chromatic aberration. 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, which has a biconcave negative power, and the ninth lens, which has a biconvex positive power, form a second cemented lens. The tenth lens, which has a biconvex positive power, and the eleventh lens, which has a 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.

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 focal length BFL of the entire optical system satisfy the following relationship: 0.1 <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, At least one of the said meniscus aspherical lenses has an Abbe number between 40 and 60.

7. 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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