CN220894635U - Close-range projection lens and projection equipment - Google Patents

Abstract

The application discloses a close-range projection lens and projection equipment. The short-distance projection lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are arranged in sequence from a projection surface to an image source surface along an optical axis; the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses; the seventh lens is an aspherical lens. Through the mode, the short-distance projection lens adopts the mode of combining six spherical lenses and one aspheric lens, so that the imaging quality can be improved, the whole volume is smaller, the quality is lighter, the cost is lower, in addition, the aberration of a projection image can be effectively corrected by the seventh lens of the aspheric lens when a light beam passes from an image source surface to a projection surface, and the imaging quality is clearer.

Description

Close-range projection lens and projection equipment

Technical Field

The application relates to the technical field of photoelectric projection, in particular to a short-distance projection lens and projection equipment.

Background

The existing projection lens is inconvenient to practical use due to longer whole body and larger volume, and the image formed by the lens is larger in distortion, so that the use experience is also influenced by blurring of image quality; in order to achieve higher imaging quality, the existing projection lens adopts more aspheric lenses to optimize aberration, the processing difficulty of the aspheric lenses is greater than that of the spherical lenses, the manufacturing cost is high, and the cost of the whole lens is sharply increased by adopting more aspheric lenses, so that the projection lens is unfavorable for mass production and application. Secondly, the number of lenses used in the design process is large, the total weight of the lens is directly increased by the large number of lenses, the volume is increased, inconvenience is caused in the actual use process, and the cost is increased.

Disclosure of utility model

In order to solve the above problems, the present application provides a close-range projection lens and a projection apparatus, which aim to solve the above problems.

In order to solve the technical problems, the application adopts a technical scheme that: the short-distance projection lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are arranged in sequence from a projection surface to an image source surface along an optical axis; the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses; the seventh lens is an aspherical lens.

The incident surface of the fifth lens is closely attached to the emergent surface of the sixth lens to form a cemented lens.

The first lens has negative focal power, and the projection surface of the first lens is a convex surface; the image source surface of the first lens is a concave surface; the second lens has negative focal power, the projection surface of the second lens is concave, and the image source surface of the second lens is convex; the third lens has positive focal power, the projection surface of the third lens is a convex surface, and the image source surface of the third lens is a convex surface; the fourth lens has negative focal power, the projection surface of the fourth lens is a convex surface, and the image source surface of the fourth lens is a concave surface; the fifth lens has negative focal power, the projection surface of the fifth lens is a concave surface, and the image source surface of the fifth lens is a concave surface; the sixth lens has positive focal power, the projection surface of the sixth lens is a convex surface, and the image source surface of the sixth lens is a convex surface; the seventh lens has positive focal power, the projection surface of the seventh lens is a convex surface, and the image source surface of the seventh lens is a convex surface.

Wherein the seventh lens is a 16-order even glass aspheric lens.

The short-distance projection lens further comprises a diaphragm, and the diaphragm is positioned between the fourth lens and the fifth lens.

Wherein, the working wavelength of the short-distance projection lens is between 460 and 620 mu m.

The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all made of glass materials.

Wherein, the optical total length of the short-distance projection lens is less than or equal to 58mm.

In order to solve the technical problems, the application adopts another technical scheme that: there is provided a projection apparatus comprising a close-up projection lens of any of the above embodiments.

The projection device further comprises a light combining prism and a protection prism, wherein the protection prism is arranged on the image source surface of the seventh lens, and the light combining prism is arranged on the image source surface of the protection prism.

The beneficial effects of the application are as follows: unlike the prior art, the short-distance projection lens of the present application includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are sequentially arranged from the projection surface to the image source surface along the optical axis; the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses; the seventh lens is an aspherical lens. Through the mode, the short-distance projection lens adopts the mode of combining six spherical lenses and one aspheric lens, so that the imaging quality can be improved, the whole volume is smaller, the quality is lighter, the cost is lower, in addition, the aberration of a projection image can be effectively corrected by the seventh lens of the aspheric lens when a light beam passes from an image source surface to a projection surface, and the imaging quality is clearer.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:

FIG. 1 is a schematic view of a close-up projection lens according to an embodiment of the present application;

FIG. 2 is a graph of optical modulation transfer function of an embodiment of a close-range projection lens of the present application;

FIG. 3 is a field curvature of an embodiment of a close-up projection lens of the present application;

FIG. 4 is a graph showing distortion of a close-range projection lens according to an embodiment of the present application under visible light;

FIG. 5 is a graph of vertical axis color difference for a near field projection lens of the present application in a visible light range;

Fig. 6 is a schematic structural view of an embodiment of the projection apparatus of the present application.

Marking: a short-distance projection lens 100, a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, a seventh lens 70, a diaphragm 80, a projection device 200, a light combining prism 110, and a protection prism 120.

Detailed Description

Embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.

In the description of embodiments of the present application, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In recent years, optical imaging lenses are widely used in the fields of smart phones, projection, vehicle-mounted security, and the like. In the projection technology, with the continuous maturity of the projection technology, the requirements for projection pictures are also continuously improved, and the requirements for the imaging quality of the imaging lens on the projection equipment are correspondingly higher and higher.

The existing projection lens is inconvenient to practical use due to longer whole body and larger volume, and the image formed by the lens is larger in distortion, so that the use experience is also influenced by blurring of image quality; in order to achieve higher imaging quality, the existing projection lens adopts more aspheric lenses to optimize aberration, the processing difficulty of the aspheric lenses is greater than that of the spherical lenses, the manufacturing cost is high, and the cost of the whole lens is sharply increased by adopting more aspheric lenses, so that the projection lens is unfavorable for mass production and application. Secondly, the number of lenses used in the design process is large, the total weight of the lens is directly increased by the large number of lenses, the volume is increased, inconvenience is caused in the actual use process, and the cost is increased.

In order to solve the above-mentioned problems, the present application firstly provides a close-range projection lens, and referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of a close-range projection lens of the present application.

As shown in fig. 1, in the present embodiment, the close-range projection lens 100 includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, and a seventh lens 70.

As shown in fig. 1, the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, the sixth lens 60 and the seventh lens 70 are arranged in order from the projection plane to the image source plane along the optical axis; in the present embodiment, the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50 and the sixth lens 60 are spherical lenses; the seventh lens 70 is an aspherical lens.

The projection surface is used for displaying the projected image, and the image source surface is used for displaying the image to be projected.

Unlike the prior art, the close-range projection lens 100 of the present application includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, and a seventh lens 70, wherein the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, the sixth lens 60, and the seventh lens 70 are sequentially arranged from the projection plane to the image source plane along the optical axis; wherein the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50 and the sixth lens 60 are spherical lenses; the seventh lens 70 is an aspherical lens. In this way, the short-distance projection lens 100 of the present application adopts a combination of six spherical lenses and one aspherical lens, so that the imaging quality can be improved, the overall volume is smaller, the quality is lighter, the cost is lower, and in addition, the aberration of the projection image can be effectively corrected by the seventh lens 70 of the aspherical lens when the light beam passes from the image source surface to the projection surface, so that the imaging quality is clearer.

Alternatively, as shown in fig. 1, based on the above embodiment, in the present embodiment, the incident surface of the fifth lens 50 is closely attached to the exit surface of the sixth lens 60 to form a cemented lens.

That is, the fifth lens 50 and the sixth lens 60 are disposed in a bonding manner, in this embodiment, the fifth lens 50 and the sixth lens 60 may be disposed in a bonding manner, in other embodiments, the fifth lens 50 and the sixth lens 60 may be disposed in a bonding manner, and the present invention is not limited thereto.

Compared with the prior art, the present application forms the cemented lens by attaching the fifth lens element 50 and the sixth lens element 60, which can correct chromatic aberration of glass and improve image quality.

Alternatively, as shown in fig. 1, based on the above-described embodiment, in the present embodiment, the first lens 10 has negative optical power, and the projection surface of the first lens 10 is convex; the image source surface of the first lens 10 is a concave surface; the second lens 20 has negative focal power, the projection surface of the second lens 20 is concave, and the image source surface of the second lens 20 is convex; the third lens element 30 has positive refractive power, wherein a projection surface of the third lens element 30 is convex, and an image source surface of the third lens element 30 is convex; the fourth lens element 40 has negative focal power, wherein a projection surface of the fourth lens element 40 is convex, and an image source surface of the fourth lens element 40 is concave; the fifth lens element 50 has negative focal power, the projection surface of the fifth lens element 50 is concave, and the image source surface of the fifth lens element 50 is concave; the sixth lens element 60 has positive refractive power, wherein a projection plane of the sixth lens element 60 is convex, and an image source plane of the sixth lens element 60 is convex; the seventh lens 70 has positive power, the projection surface of the seventh lens 70 is convex, and the image source surface of the seventh lens 70 is convex.

As shown in fig. 1, the first lens 10 is a meniscus concave lens with a concave surface facing the projection surface, the second lens 20 is a meniscus concave lens with a concave surface facing the image source surface, the third lens 30 is a biconvex lens, the fourth lens 40 is also a meniscus concave lens with a concave surface facing the projection surface, the fifth lens 50 is a biconcave lens, the sixth lens 60 is a biconvex lens, and the seventh lens 70 is also a biconvex lens.

In this embodiment, table 1 shows parameters of each lens assembly of the close-range projection lens 100 provided in this embodiment, including a radius of curvature, a pitch, and a refractive index. The mirror numbers 1-13 are mirror numbers of lenses from left to right in the close-range projection lens 100 provided in fig. 1. The first lens 10 is numbered 1 and 2, the second lens 20 is numbered 3 and 4, the third lens 30 is numbered 5 and 6, the fourth lens 40 is numbered 7 and 8, the fifth lens 50 is numbered 9 and 10, the sixth lens 60 is numbered 10 and 11, and the seventh lens 70 is numbered 12 and 13.

TABLE 1

Alternatively, based on the above-described embodiments, the seventh lens 70 is a 16-order even glass aspherical lens in the present embodiment.

In the embodiment, the seventh lens 70 is a 16-order even aspheric lens, and the object-measuring surface and the image-measuring surface of the aspheric lens are aspheric. The equation for the aspherical lens surface profile is as follows:

Wherein z is the axial sagittal height of the aspheric surface; r is the height of the aspheric surface; c is the curvature of the fitting sphere, and the numerical value is the reciprocal of the curvature radius; k is a fitting cone coefficient; alpha ₁、α₂、α₃、α₄、α₅、α₆、α₇、α₈ is the 1 st, 4 th, 6 th, 8 th, 10 th, 12 th, 14 th and 16 th order term coefficient of the aspherical polynomial, respectively.

The relevant parameters of the seventh lens 70 in this embodiment are shown in table 2:

TABLE 2

In other embodiments, the seventh lens 70 may be any even-order aspheric lens, and may be set based on the actual requirement of the close-range projection lens 100, which is not limited herein.

In this embodiment, the seventh lens adopts an aspheric lens, and other lenses adopt spherical lenses, so that not only a short working distance from the projection lens is realized, but also the short-distance projection lens 100 has higher imaging quality, and the whole volume is smaller and the mass is lighter.

In this embodiment, the light beam passes through the seventh lens 70 from the image source surface to the projection surface, and the seventh lens 70 is configured as an aspheric lens to effectively correct the aberration of the projected image, so that the imaging quality is clearer.

Optionally, as shown in fig. 1, the close-range projection lens 100 further includes a diaphragm 80, and the diaphragm 80 is located between the fourth lens 40 and the fifth lens 50.

In the present embodiment, the fourth lens 40 and the fifth lens 50 are spaced apart from each other; the distance between the fourth lens 40 and the fifth lens 50 is far, so that a diaphragm 80 is disposed between the fourth lens 40 and the fifth lens 50, the diaphragm 80 can limit the propagation range of the light beam between the fourth lens 40 and the fifth lens 50, control the incident angle and the light intensity distribution of the light beam, and eliminate astigmatism, distortion and chromatic aberration of magnification, thereby improving the imaging quality and performance of the short-distance projection lens 100.

Alternatively, the short-range projection lens 100 has an operating wavelength between 460 and 620 μm.

The working wavelength of the close-range projection lens 100 of the embodiment is between 460 μm and 620 μm, that is, the close-range lens of the embodiment can be used in a visible light field, and the application range is wider.

Optionally, the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, the sixth lens 60 and the seventh lens 70 are all made of glass materials.

That is, the lenses in this embodiment may be made of glass, and have good heat resistance, so that the short-distance projection lens 100 can work normally even in a high-temperature state.

Optionally, the optical total length of the close-range projection lens 100 is less than or equal to 58mm.

In this embodiment, the total optical length of the entire close-range projection lens 100 is less than or equal to 58mm, and compared with the prior art, the close-range projection lens 100 of this embodiment has smaller volume and wider applicable scene.

In an application scenario, referring to fig. 2, fig. 2 is a graph showing an optical modulation transfer function of an embodiment of a close-range projection lens according to the present application, and it can be seen that the value of the modulation transfer function of the close-range projection lens 100 is still greater than 0.6 under the condition that the spatial frequency is 66lp/mm, so as to meet the requirement of image definition.

Referring to fig. 3, fig. 3 is a field curvature diagram of an embodiment of a close-range projection lens according to the present application. Wherein the field Qu Youchen "field curvature". When the lens is curved, the intersection point of the whole light beam does not coincide with the ideal image point, and although a clear image point can be obtained at each specific point, the whole image plane is a curved surface. Wherein T represents meridian field curvature and S represents sagittal field curvature. The field curvature curve shows the distance of the current focal plane or image plane to the paraxial focal plane as a function of the field coordinates, and the meridian field curvature data is the distance measured along the Z-axis from the currently determined focal plane to the paraxial focal plane and is measured on the meridian (YZ-plane). The sagittal field curvature data measures the distance measured in a plane perpendicular to the meridian plane, the base line in the diagram being on the optical axis, the top of the curve representing the maximum field of view (angle or height), and no units being placed on the longitudinal axis, since the curve is always normalized by the maximum radial field of view.

As shown in fig. 3, it can be seen that the curvature of field of all fields of view of the close-range projection lens 100 of the present embodiment is substantially small in coincidence chromatic aberration.

Referring to fig. 4, fig. 4 is a distortion chart of a close-range projection lens according to an embodiment of the application under visible light. Generally, lens distortion is actually a generic term for perspective distortion inherent to an optical lens, that is, distortion due to perspective, which is very detrimental to the imaging quality of a photograph, and after all, the purpose of photographing is to reproduce, not exaggerate, but cannot be eliminated and only improved because it is inherent characteristics of the lens (convex lens converging light, concave lens diverging light).

As shown in fig. 4, the close-range projection lens 100 of the present embodiment has a smaller maximum distortion ratio, and thus has better optical performance.

Referring to fig. 5, fig. 5 is a vertical axis color difference chart of a near field projection lens according to an embodiment of the application under visible light.

As shown in fig. 5, in the present embodiment, the chromatic aberration of magnification of the other wavelengths is smaller than 3.5um, and therefore, the chromatic aberration of the projection image formed by the short-distance projection lens 100 of the present embodiment is small, and the color reproducibility of the image is high.

As can be seen from the data analysis of the above graphs, the short-distance projection lens of the embodiment can meet the requirement of image definition, and the curvature of field of all view fields is basically smaller in coincident chromatic aberration, has smaller maximum distortion rate, better optical performance and higher image color reduction degree.

The present application further provides a projection apparatus, please refer to fig. 6, fig. 6 is a schematic structural diagram of an embodiment of the projection apparatus of the present application. As shown in fig. 6, the projection apparatus 200 of the present embodiment includes the short-range projection lens 100 of any of the above-described embodiments.

Optionally, as shown in fig. 6, the projection apparatus 200 of the present embodiment further includes a light combining prism 110 and a protection prism 120, the protection prism 120 is disposed on the image source surface of the seventh lens 70, and the light combining prism 110 is disposed on the image source surface of the protection prism 120.

In this embodiment, the projection device 200 includes, but is not limited to, an engineering projector, a micro laser projector, or a commercial projector. In the projection apparatus 200, after the projection beam is emitted from the image source surface, before the projection beam enters the seventh lens 70, the projection beam needs to pass through the light combining prism 110 and the protection prism 120, that is, the projection beam sequentially passes through the light combining prism 110, the protection prism 120, the seventh lens 70, the sixth lens 60, the fifth lens 50, the fourth lens 40, the third lens 30, the second lens 20, and the first lens 10, and reaches the projection surface to form a projection image.

The foregoing description is only illustrative of the present application and is not intended to limit the scope of the application, and all equivalent structures or equivalent processes or direct or indirect application in other related technical fields are included in the scope of the present application.

Claims (10)

1. The short-distance projection lens is characterized by comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are arranged in sequence from a projection surface to an image source surface along an optical axis;

Wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses; the seventh lens is an aspherical lens.

2. The close-range projection lens of claim 1, wherein the entrance surface of the fifth lens is closely attached to the exit surface of the sixth lens to form a cemented lens.

3. The close-up projection lens of claim 1, wherein the first lens has negative optical power, and a projection surface of the first lens is convex; the image source surface of the first lens is a concave surface; the second lens has negative focal power, the projection surface of the second lens is a concave surface, and the image source surface of the second lens is a convex surface; the third lens has positive focal power, the projection surface of the third lens is a convex surface, and the image source surface of the third lens is a convex surface; the fourth lens has negative focal power, the projection surface of the fourth lens is a convex surface, and the image source surface of the fourth lens is a concave surface; the fifth lens has negative focal power, the projection surface of the fifth lens is a concave surface, and the image source surface of the fifth lens is a concave surface; the sixth lens has positive focal power, the projection surface of the sixth lens is a convex surface, and the image source surface of the sixth lens is a convex surface; the seventh lens has positive focal power, the projection surface of the seventh lens is a convex surface, and the image source surface of the seventh lens is a convex surface.

4. The close-up projection lens of claim 1, wherein the seventh lens is a 16 th order even glass aspheric lens.

5. The close-up projection lens of claim 1, further comprising a stop positioned between the fourth lens and the fifth lens.

6. The close-up projection lens of claim 1, wherein the operating wavelength of the close-up projection lens is between 460 and 620 μm.

7. The close-up projection lens of claim 1, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all glass materials.

8. The close-up projection lens of claim 1, wherein an optical total length of the close-up projection lens is less than or equal to 58mm.

9. A projection apparatus comprising a close-range projection lens according to any one of claims 1 to 8.

10. The projection device of claim 9, further comprising a light combining prism and a protective prism, wherein the protective prism is disposed on the image source surface of the seventh lens, and the light combining prism is disposed on the image source surface of the protective prism.