CN219370112U - Off-axis imaging lens assembly and projector - Google Patents

Abstract

The utility model discloses an off-axis imaging lens component, wherein the value range of a focal length f 'is 50mm < f' < 200mm; the method comprises the steps of sequentially arranging an LCD screen, a Fresnel lens and an imaging lens; the size centers of the LCD screen and the Fresnel lens are on the same axis, and the optical thread center of the Fresnel lens and the size center of the LCD screen are offset; the optical thread center of the Fresnel lens and the imaging lens are on the same axis; the imaging lens comprises a lens shell, and a first positive lens, a negative lens and a second positive lens which are sequentially arranged in the lens shell. The utility model effectively solves the problem that the lower half part of the projection picture of the projector is easy to be covered by the desktop in the prior art.

Description

Off-axis imaging lens assembly and projector

Technical Field

The utility model relates to the technical field of projection equipment, in particular to an off-axis imaging lens assembly and a projector.

Background

Currently, single LCD projectors are commercially available, and basically, a mode of 0% offset (0 offset) is adopted, that is, the LCD liquid crystal display center, the fresnel lens center, and the imaging lens center are on the same axis, and the projected imaging is central symmetrical with respect to the screen. The single LCD projector lens design of 0 offset (0 off axis) is relatively simple, but the lower half of the projected picture is easily blocked by the desktop during the actual projection process, which severely affects the consumer experience; in order to eliminate the problem that the lower half of the projection picture is blocked by the desktop, a plurality of manufacturers adopt a mode of increasing the height of the projector, including adding a support frame under the projector or making the projector vertical, and the two modes can only solve a part of problems; meanwhile, the imaging lens in the prior art generally adopts a full glass design, so that the imaging lens has heavy weight, difficult distortion correction and insufficient definition of the corners of a projection picture; therefore, an off-axis imaging lens assembly and a projector are provided, which are used for solving the problem that the lower half part of a projection picture of the projector is easy to be covered by a desktop in the prior art.

Disclosure of Invention

One of the objectives of the present utility model is to provide an off-axis imaging lens assembly and a projector, so as to solve the problem that the lower half of the projection screen of the projector is easily covered by a desktop in the prior art.

The off-axis imaging lens assembly and the projector can be realized by the following technical scheme:

the off-axis imaging lens component has the value range of the focal length f 'of 50mm < f' < 200mm; the method comprises the steps of sequentially arranging an LCD screen, a Fresnel lens and an imaging lens; the size centers of the LCD screen and the Fresnel lens are on the same axis, and the optical thread center of the Fresnel lens and the size center of the LCD screen are offset; the optical thread center of the Fresnel lens and the size center of the imaging lens are on the same axis; the imaging lens comprises a lens shell, and a first positive lens, a negative lens and a second positive lens which are sequentially arranged in the lens shell.

In one embodiment, the focal length of the first positive lens is f1', and the value range is 0.2 < f1 '/f ' < 2.0.

In one embodiment, the focal length of the negative lens is f2', and the value range of the negative lens is-2 < f2 '/f ' < -0.2.

In one embodiment, the focal length of the second positive lens is f3', and the value range is 0.2 < f3 '/f ' < 2.0.

In one embodiment, the fresnel lens is rectangular in shape; the focal length of the Fresnel lens is ff ', and the value range is 0.2 < ff '/f ' < 2.0.

In one embodiment, the first positive lens and the second positive lens are spherical surfaces, and the negative lens is an aspherical surface.

In one embodiment, the negative lens is a rotationally symmetric even aspherical surface.

In one embodiment, the first positive lens and the second positive lens are both made of glass, and the negative lens is made of plastic.

In one embodiment, an off-axis imaging lens assembly of the present utility model further comprises a mirror; the LCD screen is arranged behind the Fresnel lens; the imaging lens is arranged on the side edge of the Fresnel lens and forms an angle of 90 degrees with the Fresnel lens; the reflector is arranged between the Fresnel lens and the imaging lens and forms an angle of 45 degrees with the Fresnel lens.

A projector comprising an imaging lens assembly as claimed in any one of the preceding claims.

Compared with the prior art, the off-axis imaging lens assembly and the projector have the beneficial effects that:

according to the off-axis imaging lens assembly and the projector, the LCD screen, the Fresnel lens and the imaging lens are sequentially arranged, and the dimension centers between the LCD screen and the Fresnel lens are on the same axis; the Fresnel lens adopts eccentric design, and the optical center of the Fresnel lens and the size center of the imaging lens are positioned on the same axis, so that the projection picture is effectively displayed on the upper half part of the projection area; meanwhile, the projector can realize the function of not shielding a projection picture by a desktop without increasing a bracket or increasing the height of a lens;

the negative lens in the imaging lens is designed into a plastic material, and through the lens combination design, the weight of the imaging lens is reduced, the distortion of a picture is corrected to a smaller value through the plastic aspheric surface, meanwhile, the definition of the corners of a projection picture is ensured, and the single price ratio glass spherical surface of the plastic aspheric lens is much lower.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present utility model and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an off-axis imaging lens assembly of a first embodiment of the present utility model, including an imaging lens and a Fresnel lens;

FIG. 2 is a schematic cross-sectional view of an imaging lens in a first embodiment of an off-axis imaging lens assembly of the present utility model shown in FIG. 1;

FIG. 3 is a schematic view showing an internal structure of the imaging lens shown in FIG. 2;

FIG. 4 is a schematic view of a Fresnel lens of the first embodiment of the off-axis imaging lens assembly of the present utility model shown in FIG. 1

Fig. 5 is a schematic structural view of a second embodiment of an off-axis imaging lens assembly according to the present utility model.

The figures indicate: 11, LCD screen; a fresnel lens; 121, optical thread center; 13, an imaging lens; 131, a lens housing; 132, a first positive lens; 133, a negative lens; 134, a second positive lens; 14, a mirror.

Description of the embodiments

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments. The components of the embodiments of the present utility model generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the utility model, as presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Examples

Referring to fig. 1 and 4, in the present embodiment, a focal length f 'of an off-axis imaging lens assembly of the present utility model has a value range of 50mm < f' < 200mm; which may include an LCD screen 11, a fresnel lens 12, and an imaging lens 13; the LCD screen 11, the Fresnel lens 12 and the imaging lens 13 are sequentially arranged, the size centers of the LCD screen 11 and the Fresnel lens 12 are on the same axis, and the optical thread center 121 of the Fresnel lens 12 and the size center of the LCD screen 11 are offset; the optical thread center 121 of the fresnel lens 12 and the size center of the imaging lens 13 are on the same axis, and the image projected by the imaging lens 13 is located at the upper half of the projection area by using an optical method.

Referring to fig. 4, in this embodiment, the fresnel lens 12 is rectangular in shape, and the size center thereof does not coincide with the optical thread center 121; the focal length of the Fresnel lens 12 is ff ' and the value range is 0.2 < ff '/f ' < 2.0.

Referring to fig. 2 and 3, in the present embodiment, the imaging lens 13 includes a lens housing 131, a first positive lens 132, a negative lens 133, and a second positive lens 134; the first positive lens 132, the negative lens 133, and the second positive lens 134 are fixedly disposed in the lens housing 131 in this order; the focal length of the first positive lens 132 is f1', and the range of the focal length is 0.2 < f1 '/f ' < 2.0; the focal length of the negative lens 133 is f2', and the value range is-2 < f2 '/f ' < -0.2; the focal length of the second positive lens 134 is f3', and the value range is 0.2 < f3 '/f ' < 2.0. In the present embodiment, the first positive lens 132 and the second positive lens 134 are spherical surfaces, the negative lens 133 is an aspherical surface, and specifically, the negative lens 133 is a rotationally symmetrical even aspherical surface. The first positive lens 132 and the second positive lens 134 are made of glass, the negative lens 133 is made of plastic or glass, in this embodiment, the negative lens 133 is made of plastic, and through such a lens combination design, the weight of the imaging lens 13 is reduced, the distortion of the image is corrected to a smaller value through the plastic aspheric surface, the definition of the corners of the projection image is ensured, and the single cost glass spherical surface of the plastic aspheric lens is much lower.

Examples

Referring to fig. 5, in the present embodiment, the focal length f 'of an off-axis imaging lens assembly of the present utility model has a value range of 50mm < f' < 200mm; which may include an LCD screen 11, a fresnel lens 12, an imaging lens 13, and a mirror 14; the LCD screen 11 is arranged behind the Fresnel lens 12, the dimension centers of the LCD screen 11 and the Fresnel lens 12 are on the same axis, and the optical thread center 121 of the Fresnel lens 12 and the dimension center of the LCD screen 11 are offset; the imaging lens 13 is arranged on the side edge of the Fresnel lens 12 and forms an angle of 90 degrees with the Fresnel lens 12, so that the size of the whole projector is reduced; the reflecting mirror 14 is disposed between the fresnel lens 12 and the imaging lens 13 and forms an angle of 45 degrees with the fresnel lens 12, the imaging lens 13 and the dimensional center of the reflecting mirror 14 are on the same axis, and an image projected by the imaging lens 13 is located at the upper half of the projection area by using an optical method.

The utility model provides a projector, comprising the imaging lens assembly.

It should be noted that, in the off-axis imaging lens assembly and projector according to the present utility model, the eccentric fresnel lens 12 is adopted, and at the same time, the optical center of the fresnel lens 12 and the dimensional center of the imaging lens 13 are on the same axis, the axis is offset from the dimensional center of the LCD screen 11 (i.e. off-axis projection), and the projection image is displayed above the desktop by using an optical method, so that the problem that the desktop shields the lower half of the projection image is avoided.

The above examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.

Claims (10)

1. An off-axis imaging lens assembly is characterized in that the value range of the focal length f 'is 50mm < f' < 200mm; the method comprises the steps of sequentially arranging an LCD screen, a Fresnel lens and an imaging lens; the size centers of the LCD screen and the Fresnel lens are on the same axis, and the optical thread center of the Fresnel lens and the size center of the LCD screen are offset; the optical thread center of the Fresnel lens and the size center of the imaging lens are on the same axis; the imaging lens comprises a lens shell, and a first positive lens, a negative lens and a second positive lens which are sequentially arranged in the lens shell.

2. The off-axis imaging lens assembly as defined in claim 1, wherein the first positive lens has a focal length f1' in a range of 0.2 < f1 '/f ' < 2.0.

3. An off-axis imaging lens assembly as defined in claim 2, wherein the negative lens has a focal length f2' in a range of-2 < f2 '/f ' < -0.2.

4. An off-axis imaging lens assembly as defined in claim 3, wherein the second positive lens has a focal length f3' in the range of 0.2 < f3 '/f ' < 2.0.

5. An off-axis imaging lens assembly as defined in claim 4, wherein said fresnel lens is rectangular in shape; the focal length of the Fresnel lens is ff ', and the value range is 0.2 < ff '/f ' < 2.0.

6. The off-axis imaging lens assembly as defined in claim 1, wherein said first positive lens and said second positive lens are spherical and said negative lens is aspherical.

7. The off-axis imaging lens assembly as recited in claim 6, wherein the negative lens is a rotationally symmetric even aspherical surface.

8. The off-axis imaging lens assembly as defined in claim 1, wherein said first positive lens and said second positive lens are both made of glass and said negative lens is made of plastic.

9. The off-axis imaging lens assembly as recited in claim 1, further comprising a mirror; the LCD screen is arranged behind the Fresnel lens; the imaging lens is arranged on the side edge of the Fresnel lens and forms an angle of 90 degrees with the Fresnel lens; the reflector is arranged between the Fresnel lens and the imaging lens and forms an angle of 45 degrees with the Fresnel lens.

10. A projector comprising an imaging lens assembly according to any one of claims 1 to 9.