Projection external wide-angle lens and projection combined lens

Abstract

The utility model discloses a projection external wide-angle lens and a projection combined lens, the projection external wide-angle lens can be matched with a projection lens, the projection external wide-angle lens is composed of two lenses, and the two lenses are respectively a second lens and a first lens which are sequentially arranged from a light incident side to a light emergent side; the first lens and the second lens are coaxially arranged, the first lens has negative focal power, and the second lens has positive focal power; the light-in surface and the light-out surface of the first lens in the direction of the optical axis are both concave surfaces; the incident surface of the second lens in the optical axis direction is a convex surface, and the emergent surface in the optical axis direction is a concave surface. The projection external wide-angle lens is used for being combined with a projection lens of a projection system, can change projection to realize switching between long-focus projection and medium-long-focus projection or short-focus projection, flexibly adapts to different scenes, is simple and compact in structure, small in size and light in weight, and has the characteristics of certain aberration elimination capability, low cost and high imaging quality.

Description

Technical Field

[0001] The utility model relates to the technical field of LCD projection lenses, and particularly relates to a projection external wide-angle lens and a projection combined lens. Background Art

[0002] Projectors are widely used. The lens is the core component of the projector. Due to cost limitations, the projector lens is basically a fixed-focus lens. With a fixed projection distance, the size of the projected image is also fixed, and it is only suitable for a single scenario, either long-focus projection or short-focus projection, that is, either only suitable for long-distance projection or only suitable for short-distance projection. Therefore, to further enlarge the image, only the projection distance can be increased. When used in some application scenarios, such as in a bedroom, due to the small space, common fixed-focus projectors cannot project a large enough image, and it is difficult to flexibly switch to suit different scenarios, resulting in limited application scenarios. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a projection external wide-angle lens and a projection combined lens to solve the above technical problems.

[0004] To achieve the above purpose, the technical solution of the utility model is as follows:

[0005] A projection external wide-angle lens can be matched with a projection lens and is composed of two lenses. The two lenses are respectively a second lens and a first lens arranged in sequence from the light incident side to the light exit side. The first lens and the second lens are coaxially arranged. The first lens has a negative focal power, and the second lens has a positive focal power;

[0006] Both the light incident surface and the light exit surface of the first lens along the optical axis direction are concave surfaces;

[0007] The light incident surface of the second lens along the optical axis direction is a convex surface, and the light exit surface along the optical axis direction is a concave surface;

[0008] And the projection external wide-angle lens satisfies the following relationships:

[0009] -65 ≤ f1 ≤ -60,

[0010] 90 ≤ f2 ≤ 100,

[0011] -0.7 ≤ f1 / f2 ≤ -0.6;

[0012] Wherein, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.

[0013] Preferably, both the first lens and the second lens are plastic aspherical lenses.

[0014] Preferably, the projection external wide-angle lens satisfies the following relationships:

[0015] 1.48 ≤ Nd1 ≤ 1.60,

[0016] 1.48 ≤ Nd2 ≤ 1.60;

[0017] wherein, Nd1 is the refractive index of the first lens, and Nd2 is the refractive index of the second lens.

[0018] Preferably, the projection external wide-angle lens satisfies the following relationship:

[0019] -3000 ≤ F1 ≤ -2500;

[0020] F1 is the focal length of the projection external wide-angle lens.

[0021] A projection combined lens, which includes a projection lens and the projection external wide-angle lens as described above, and the projection external wide-angle lens is detachably mounted on the light-emitting side of the projection lens.

[0022] Preferably, the projection combined lens satisfies the following relationship:

[0023] 70 ≤ F2 ≤ 100,

[0024] 40 ≤ F3 ≤ 60,

[0025] 0.55 ≤ F3 / F2 ≤ 0.60;

[0026] wherein, F2 is the focal length of the projection lens, and F3 is the total focal length of the projection combined lens.

[0027] Preferably, the projection combined lens satisfies the following relationship:

[0028] 1.15 ≤ TR1 ≤ 1.35,

[0029] 0.55 ≤ TR2 ≤ 0.7;

[0030] wherein, TR1 is the projection ratio of the projection lens, and TR2 is the projection ratio of the projection combined lens.

[0031] Preferably, the center of the projection external wide-angle lens coincides with the center of the projection lens. Compared with the prior art, the beneficial effects of the present utility model are:

[0032] The projection external wide-angle lens of the present utility model is used to be combined with the projection lens of the projection system, and can change the projection to realize the switching between telephoto projection, medium telephoto projection or short-focus projection, flexibly adapt to different scenarios, has a simple and compact structure, is miniaturized and light in weight, has certain aberration correction ability, low cost and high imaging quality. Description of the Drawings

[0033] Figure 1 This is a schematic structural diagram of the projection combined lens of the present utility model;

[0034] In the figure:

[0035] 1. Projection external wide-angle lens; 11. First lens; 12. Second lens; 2. Projection lens. Specific embodiments

[0036] To further elaborate on the technical means and effects adopted by the present utility model to achieve the predetermined utility model purpose, the following, in combination with the accompanying drawings and preferred embodiments, details the specific embodiments, structures, features and their effects of the present utility model as follows.

[0037] Please refer to Figure 1 , the embodiment of the present utility model provides a projection external wide-angle lens 1, which can be combined with a projection lens 2 to form a projection combined lens. The projection external wide-angle lens 1 is composed of two lenses, and the two lenses are respectively the second lens 12 and the first lens 11 arranged in sequence from the incident light side to the outgoing light side.

[0038] The first lens 11 and the second lens 12 are coaxially arranged. The first lens 11 has a negative focal power, and the second lens 12 has a positive focal power. The focal power is used to represent the ability of a short-focus lens to deflect light. Among them, a lens with a positive focal power indicates that it has the ability to converge light, and a lens with a negative focal power indicates that it has the ability to diverge light.

[0039] Among them, the incident light surface 111 and the outgoing light surface 112 of the first lens 11 along the optical axis direction are both concave surfaces; the incident light surface 121 of the second lens 12 along the optical axis direction is a convex surface, and the outgoing light surface 122 along the optical axis direction is a concave surface.

[0040] And the projection external wide-angle lens 1 satisfies the following relationship:

[0041] -65 ≤ f1 ≤ -60,

[0042] 90 ≤ f2 ≤ 100,

[0043] -0.7 ≤ f1 / f2 ≤ -0.6;

[0044] Among them, f1 is the focal length of the first lens 11, and f2 is the focal length of the second lens 12.

[0045] The projection external wide-angle lens 1 described in the embodiments of the present application is detachably mounted outside the projection lens 2 of an existing projector, and can form a projection combined lens. When the projection external wide-angle lens 1 is mounted outside the projection lens 2, the image light beam generated inside the projector needs to pass through the projection lens 2 and the projection external wide-angle lens 1 in sequence before being projected onto the projection screen. The projection external wide-angle lens 1 further processes the image light beam to change the overall projection ratio (the projection ratio refers to the ratio of the projection distance to the width of the projection screen). That is, the projection ratio achieved when the projection external wide-angle lens 1 is installed is different from the projection ratio when the projection system projects only through the projection lens 2, enabling the projector to adapt to different projection scenarios, and can change from long-focus projection to medium-long-focus projection or short-focus projection, or from medium-long-focus projection or short-focus projection to long-focus projection, and can multiply the screen size at the same projection distance.

[0046] Moreover, under the combined action of the above two lenses, the projection external wide-angle lens 1 has a simple, compact structure, is miniaturized and lightweight through reasonable distribution of the lens focal lengths, has certain aberration correction capabilities, low cost, and high imaging quality, which is beneficial to improving the overall performance of the projection combined lens.

[0047] Preferably, both the first lens 11 and the second lens 12 are plastic aspherical lenses. That is, both surfaces of the first lens 11 and the second lens 12 are aspherical surfaces. Aspherical lenses have more degrees of freedom, can better reduce the aberration of the entire projection lens 2, and improve the imaging quality. At the same time, they are lighter, thinner, and flatter, which is beneficial to the miniaturization of the projection lens 2. Using aspherical lenses not only meets the miniaturization of the projection lens 2 but also meets the requirements of high imaging quality.

[0048] Preferably, the projection external wide-angle lens 1 satisfies the following relationships:

[0049] 1.48 ≤ Nd1 ≤ 1.60,

[0050] 1.48 ≤ Nd2 ≤ 1.60;

[0051] Wherein, Nd1 is the refractive index of the first lens 11, and Nd2 is the refractive index of the second lens 12. The reasonable distribution of the lens refractive indices helps to improve the environmental adaptability of the short-focus lens.

[0052] Preferably, the projection external wide-angle lens 1 satisfies the following relationships:

[0053] -3000 ≤ F1 ≤ -2500;

[0054] The F1 is the focal length of the projection external wide-angle lens 1. By setting as above, the focal length of the projection external wide-angle lens 1 can be within this range, and a two-fold picture magnification function can be achieved.

[0055] Preferably, this embodiment also provides a projection combined lens, which includes a projection lens 2 and the projection external wide-angle lens 1 of this embodiment. The projection external wide-angle lens 1 is detachably mounted on the light-emitting side of the projection lens 2.

[0056] Preferably, the projection combined lens satisfies the following relationship:

[0057] 70 ≤ F2 ≤ 100,

[0058] 40 ≤ F3 ≤ 60,

[0059] 0.55 ≤ F3 / F2 ≤ 0.60;

[0060] Wherein, the F2 is the focal length of the projection lens 2, and the F3 is the total focal length of the projection combined lens. Through reasonable focal length settings, it is ensured that the projection external wide-angle lens 1 and the projection lens 2 can be better matched to ensure the light-emitting quality.

[0061] Preferably, the projection combined lens satisfies the following relationship:

[0062] 1.15 ≤ TR1 ≤ 1.35,

[0063] 0.55 ≤ TR2 ≤ 0.7;

[0064] Wherein, the TR1 is the projection ratio of the projection lens 2, and the TR2 is the projection ratio of the projection combined lens. With this setting, the picture can be magnified to about 2 times the original picture size at the same projection distance, and high-quality projection can be ensured.

[0065] Specifically, the center of the projection external wide-angle lens 1 in this embodiment coincides with the center of the projection lens 2, so that the projection external wide-angle lens 1 can better perform transmission processing on the image light beam, improve the light-emitting quality, and improve the resolution of the central area of the projection picture.

[0066] The specific design parameters of the projection external wide-angle lens 1 in this embodiment are shown in Table 1 below:

[0067] Table 1

[0068]

[0069] Among them, the aspheric surface type expressions of the first lens 11 and the second lens 12 in this application are:

[0070]

[0071] In the above formula, z is the sag of the aspheric surface, r is the radius of the aspheric surface, k is the conic coefficient, and c is the curvature. The specific parameters are shown in Table 2.

[0072] Table 2

[0073] Surface number X α1 α2 α3 α4 α5 α6 α7 111 -17.4 0 2.6E-05 -7.5E-08 1.02E-10 3.4E-14 -1.8E-15 0 112 49.81 0 1.1E-04 -1E-06 5.978E-09 -2.02E-12 3.046E-14 0 122 -108.7 0 -4.38-05 3.9E-07 -2.85E-09 7.19E-12 -9.7E-14 0 121 -0.55 0 -7.13E-05 5.90E-08 -4.35E-10 1.712E-12 -2.29E-15 0

[0074] Among them, the parameters to be explained are as follows:

[0075] The focal length f1 of the first lens 11 is -61 mm;

[0076] The focal length f2 of the second lens 12 is 95 mm;

[0077] The focal length F1 of the projection external wide-angle lens 1 is -2815 mm;

[0078] The focal length F2 of the projection lens 2 is 78 mm;

[0079] The focal length F3 of the projection combined lens is 46 mm;

[0080] In this solution, the projection ratio TR1 of the projection lens is 1.2, and the projection ratio TR2 of the projection combined lens is 0.6, which can achieve a 2-fold picture magnification function.

[0081] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the equivalent embodiments of the equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A projection external wide-angle lens, which can be used in cooperation with a projection lens, is characterized in that It consists of two lenses, namely a second lens and a first lens arranged in sequence from the incident light side to the outgoing light side. The first lens and the second lens are coaxially arranged. The first lens has a negative optical power, and the second lens has a positive optical power; Both the incident light surface and the outgoing light surface of the first lens along the optical axis direction are concave surfaces; The incident light surface of the second lens along the optical axis direction is a convex surface, and the outgoing light surface along the optical axis direction is a concave surface; And the projection external wide-angle lens satisfies the following relationship: -65≤f1≤-60， 90≤f2≤100， -0.7 ≤ f1 / f2 ≤ -0.6; Wherein, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.

2. The projection external wide-angle lens according to claim 1, characterized in that: Both the first lens and the second lens are plastic aspherical lenses.

3. The projection external wide-angle lens according to claim 1, wherein Satisfy the following relationship: 1.48 ≤ Nd1 ≤ 1.60, 1.48 ≤ Nd2 ≤ 1.60; Wherein, Nd1 is the refractive index of the first lens, and Nd2 is the refractive index of the second lens.

4. The projection external wide-angle lens according to claim 1, characterized in that, Satisfy the following relationship: -3000≤F1≤-2500； F1 is the focal length of the projection external wide-angle lens.

5. A projection combination lens, characterized in that, It includes a projection lens and the projection external wide-angle lens according to any one of claims 1-4. The projection external wide-angle lens is detachably mounted on the outgoing light side of the projection lens.

6. The projection combination lens according to claim 5, wherein Satisfy the following relationship: 70≤F2≤100， 40≤F3≤60， 0.55 ≤ F3 / F2 ≤ 0.60; Wherein, F2 is the focal length of the projection lens, and F3 is the total focal length of the projection combined lens.

7. The projection combination lens according to claim 5, wherein Satisfy the following relationship: 1.15 ≤ TR1 ≤ 1.35, 0.55 ≤ TR2 ≤ 0.7; Wherein, TR1 is the projection ratio of the projection lens, and TR2 is the projection ratio of the projection combined lens.

8. The projection combined lens according to claim 5, characterized in that: The center of the projection external wide-angle lens coincides with the center of the projection lens.

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