CN215219402U - Short-focus projection lens and projection equipment thereof - Google Patents

Abstract

The application discloses a short-focus projection lens and projection equipment thereof, wherein the short-focus projection lens comprises an optical lens group and a diaphragm, and the optical lens group is used for imaging a micro image into a projection image; the optical lens group comprises a first lens group and a second lens group, and the first lens group is used for imaging the micro-image into an intermediate image; the second lens group is used for imaging the intermediate image into a projection image; the diaphragm is arranged between the first lens group and the second lens group, and the diaphragm, the first lens group and the second lens group have the same main optical axis; wherein the offset of the projection image relative to the main optical axis is 180% -200%. The method comprises the steps that a micro image is imaged into an intermediate image with small distortion through a first lens group; and then the intermediate image is imaged into a projection image by the second lens group, aberration can be effectively improved through two imaging processes, and the offset of the projection image relative to the main optical axis is 180% -200%, so that the short-focus projection lens can project a larger projection picture at a shorter projection distance.

Description

Short-focus projection lens and projection equipment thereof

Technical Field

The application relates to the technical field of optical systems, in particular to a short-focus projection lens and projection equipment thereof.

Background

The projector is very popular because it can project large-size pictures, in recent years, users want to build a larger display screen through the projector, so that the size of the display screen can reach 200 inches, 300 inches or even more than 500 inches, and better visual impact can be obtained, but the size of the projection picture is limited by the size of an occasion space and the projection distance, and the projection characteristic is that the farther the installation distance is, the larger the projection picture is, and conversely, the closer the installation distance is, the smaller the projection picture is. At present, an oversized picture is realized in a limited space and can only be formed by splicing and fusing a plurality of projectors, but the cost of the solution is increased sharply and violently, and a user can feel. Therefore, how to realize an ultra-large picture in a limited distance space becomes an urgent key.

SUMMERY OF THE UTILITY MODEL

The technical problem that this application mainly solved provides a short burnt projection lens and projection equipment thereof, solves the problem of how to realize the super large picture in limited distance space among the prior art.

In order to solve the above technical problem, the first technical solution adopted by the present application is: there is provided a short focus projection lens comprising: an optical lens group for imaging the microimages into a projected image; the optical lens group comprises a first lens group and a second lens group, and the first lens group is used for imaging the micro-image into an intermediate image; the second lens group is used for imaging the intermediate image into a projection image; the diaphragm is arranged between the first lens group and the second lens group, and the diaphragm, the first lens group and the second lens group have the same main optical axis; wherein the offset of the projection image relative to the main optical axis is 180% -200%.

The first lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens; the first lens, the third lens and the fourth lens are biconvex lenses, the fifth lens is a biconcave lens, the sixth lens is a positive crescent lens, and the second lens is a negative crescent lens.

Wherein, the fifth lens and the sixth lens are glued into a whole.

Wherein the second lens group includes a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, and a fourteenth lens; the ninth lens and the fourteenth lens are aspheric lenses, the tenth lens is a double convex lens, the seventh lens and the eighth lens are positive crescent lenses, and the eleventh lens, the twelfth lens and the thirteenth lens are negative crescent lenses; wherein, the aspheric lens is an even aspheric lens.

Wherein, the tenth lens and the eleventh lens are glued into a whole.

Wherein, the projection ratio of the short-focus projection lens is 0.6-0.8.

The short-focus projection lens has an effective focal length of 5.1mm, a relative aperture of 1.7, a maximum aperture of less than 70mm, an optical total length of 113mm and a telecentricity of less than 1 degree.

The optical lens group comprises fourteen lenses, the front thirteen lenses close to the micro-image are made of glass, and the lens far away from the micro-image is made of plastic.

In order to solve the above technical problem, the second technical solution adopted by the present application is: there is provided a projection device comprising: the display chip is used for displaying the micro-image and serves as an object plane of the short-focus projection lens; the short-focus projection lens is the short-focus projection lens.

Wherein, the display chip is a digital micromirror device; the digital micromirror device is 0.33 inches and the resolution of the digital micromirror device is 1368 x 768.

The beneficial effect of this application is: in contrast to the prior art, the present application provides a short focus projection lens that images a micro-image as a projected image through an optical lens group; specifically, the micro image is imaged into an intermediate image with small distortion amount through the first lens group; the intermediate image is imaged into a projection image through the second lens group, aberration can be effectively improved through two imaging, and the resolution of imaging and the imaging quality can be improved through arranging the diaphragm between the first lens group and the second lens group; the offset of the projection image relative to the main optical axis is 180% -200%, so that the short-focus projection lens can project a large projection picture in a short projection distance.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of a projection apparatus according to the present application;

FIG. 2(a) is an image circle of a short-focus projection lens in the prior art;

fig. 2(b) is an image circle of the short-focus projection lens in the present application.

Detailed Description

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, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first", "second" and "third" in this application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any indication of the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise. All directional indications (such as up, down, left, right, front, and rear … …) in the embodiments of the present application are only used to explain the relative positional relationship between the components, the movement, and the like in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indication is changed accordingly. The terms "comprising" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or may alternatively include other steps or elements inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase 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. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a projection apparatus according to the present application. The projection apparatus 1 of the present application includes a short-focus projection lens 2 and a display chip 170. The display chip 170 is used to display the micro image and serves as an object plane of the projection lens. In a preferred embodiment, the display chip 170 is a Digital Micro-mirror Device DMD (Digital Micro-mirror Device) for modulating the light beam from the illumination system in the projection Device 1 to display a Micro-image, serving as the object plane of the projection Device 1. The digital micromirror device in this application is 0.33 inches and the resolution of the digital micromirror device is 1368 x 768. The relative aperture (D/f') of the projection device is 1.7; the rear working distance of the projection device is 30.5 mm.

The short focus projection lens 2 includes an optical lens group 3 and a diaphragm 150. Wherein, the projection ratio of the short-focus projection lens 2 is 0.6-0.8. In an alternative embodiment, the throw ratio of the short focus projection lens 2 is 0.7. The effective focal length of the short-focus projection lens 2 is 5.1mm, the relative aperture is 1.7, the maximum aperture is less than 70mm, the optical total length is 113mm, and the telecentricity is less than 1 degree. In a specific embodiment, the projection ratio of the short-focus projection lens 2 in the projection apparatus 1 is 0.7, the distance from the projection apparatus 1 to the imaging plane is 2 meters, and the short-focus projection lens 2 in the projection apparatus 1 can project a 130-inch screen on the imaging plane.

In this embodiment, the optical lens group 3 is used to image the microimages into a projected image. The optical lens group 3 includes fourteen lenses. In a specific embodiment, the optical lens group 3 includes a first lens group 31 and a second lens group 32.

The first lens group 31 is used to image the microimages as intermediate images. In one embodiment, the first lens group 31 includes a first lens 140, a second lens 130, a third lens 120, a fourth lens 110, a fifth lens 100, and a sixth lens 90; the first lens 140, the third lens 120, and the fourth lens 110 are biconvex lenses, the fifth lens 100 is a biconcave lens, the sixth lens 90 is a positive crescent lens, and the second lens 130 is a negative crescent lens. Wherein the fifth lens 100 and the sixth lens 90 are cemented into a single body. The first lens 140, the second lens 130, the third lens 120, the fourth lens 110, the fifth lens 100, and the sixth lens 90 are made of glass. In a specific embodiment, the materials of the first lens 140, the second lens 130, the third lens 120, the fourth lens 110, the fifth lens 100 and the sixth lens 90 are H-LAF6LA, H-BAF5, P-SK58A, H-ZK50GT, H-ZF52TT and N-SK2 in sequence.

The light with different wavelengths and different colors has different refractive indexes when passing through the lens, so that one point of an object space can form a color spot on an image space or the image is provided with a halo, and the image is blurred. Therefore, spherical aberration and chromatic aberration need to be eliminated to improve the imaging quality. In the present embodiment, the fifth lens 100 and the sixth lens 90 are cemented into one body in order to eliminate spherical aberration and chromatic aberration. The single convex lens has negative spherical aberration and the single concave lens has positive spherical aberration, so that the spherical aberration can be effectively eliminated by gluing the single convex lens and the single concave lens. In general, a convex lens produces negative chromatic aberration, and a concave lens produces positive chromatic aberration. Since the fifth lens 100 is a biconcave lens, the sixth lens 90 is an orthodontic lens. Therefore, the sixth lens 90 of the convex lens and the fifth lens 100 of the concave lens are cemented as a whole so that their chromatic aberrations compensate each other. That is, the whole of the fifth lens 100 and the sixth lens 90 cemented together is cemented by two different kinds of lenses, correcting the dispersion of the glass. While eliminating chromatic aberration, the positive and negative spherical aberration can be reduced as much as possible, and the residual spherical aberration is generated to balance the spherical aberration of other lenses.

The second lens group 32 is used to image the intermediate image as a projected image. In a specific embodiment, the second lens group 32 includes a seventh lens 80, an eighth lens 70, a ninth lens 60, a tenth lens 50, an eleventh lens 40, a twelfth lens 30, a thirteenth lens 20, and a fourteenth lens 10; the ninth lens 60 and the fourteenth lens 10 are aspherical lenses, the tenth lens 50 and the eighth lens 70 are double convex lenses, the seventh lens 80 is a positive meniscus lens, and the eleventh lens 40, the twelfth lens 30 and the thirteenth lens 20 are negative meniscus lenses; wherein, the aspheric lens is an even aspheric lens.

The seventh lens element 80, the eighth lens element 70, the ninth lens element 60, the tenth lens element 50, the eleventh lens element 40, the twelfth lens element 30 and the thirteenth lens element 20 are made of glass, and the fourteenth lens element 10 is made of plastic. In a specific embodiment, the seventh lens element 80, the eighth lens element 70, the ninth lens element 60, the tenth lens element 50, the eleventh lens element 40, the twelfth lens element 30, the thirteenth lens element 20 and the fourteenth lens element 10 are made of H-K5, H-ZF3, D-K5, H-ZF71, H-LAK4L, H-LAK10, H-ZLAF55C and E48R in sequence. Among them, the ninth lens 60 and the fourteenth lens 10 are aspherical lenses. In one embodiment, the ninth lens 60 and the fourteenth lens 10 are even aspheric lenses. In particular, the ninth lens 60 and the fourteenth lens 10 can eliminate phase difference and improve the imaging quality of the projection apparatus 1. Specifically, when the equivalent focal length of the short-focus projection lens 2 of the projection apparatus is 1, the parameters of the short-focus projection lens 2 are shown in table 1.

TABLE 1 parameters of individual lenses of a short-focus projection lens

Wherein the tenth lens 50 and the eleventh lens 40 are cemented as a single body. Wherein the tenth lens 50 of the convex lens and the eleventh lens 40 of the concave lens are cemented as a whole so that their chromatic aberrations compensate each other. That is, the tenth lens 50 and the eleventh lens 40 are cemented together with two different lenses to correct chromatic dispersion of glass. While eliminating chromatic aberration, the positive and negative spherical aberration can be reduced as much as possible, and the residual spherical aberration is generated to balance the spherical aberration of other lenses.

The stop 150 is disposed between the first lens group 31 and the second lens group 32 for controlling the light throughput. In the present embodiment, the stop 150 is disposed between the first lens group 31 and the second lens group 32, so as to improve the image definition, control the depth of field, improve the imaging quality, and further control the range of the imaged object space and control the brightness of the image plane. The diaphragm 150 is disposed at the position of the intermediate image, so that the imaging quality of the off-axis point can be improved, the reflected light spot component can be eliminated, and the effect of improving the image contrast can be obtained. In addition, the light path is increased by arranging the reflecting mirror on the light propagation path, so that short-focus projection is realized. The structure of this application makes this projection optical system have lower transmittance, consequently, the ultrashort burnt projecting lens 2 of this application has realized the big image of short distance projection, and the image quality is high.

In an embodiment, the stop 150 has the same main optical axis as the first lens group 31 and the second lens group 32. Wherein the offset of the projection image relative to the main optical axis is 180% -200%. In an alternative embodiment, the projected image is offset by 192% with respect to the primary optical axis. Referring to fig. 2(a) and 2(b), fig. 2(a) is an image circle of a short-focus projection lens in the prior art; fig. 2(b) is an image circle of the short-focus projection lens in the present application. Compared with the imaging circle when the offset of the projection image projected by the short-focus projection lens 2 relative to the main optical axis is 100% in the prior art, the imaging circle when the offset of the projection image relative to the main optical axis is 192% in the embodiment is obviously enlarged, and further the imaging range is enlarged.

The prism 160 is disposed between the display chip 170 and the first lens assembly 31, and the prism 160 is used for totally reflecting the light emitted from the illumination system to the display chip 170.

In the projection apparatus 1 provided in this embodiment, the incident light emitted from the projection light source illuminates the micro image on the display chip 170 through the prism 160, and then is reflected by the prism 170 to enter the second lens group 32, and the light is refracted to the diaphragm 150 through the second lens group 32, and then enters the first lens group 31 to be refracted to the imaging surface of the external screen, so as to enlarge and project the micro image of the prism 170 onto the imaging surface.

In conclusion, the present application improves aberration by forming an intermediate image; by the arrangement of the diaphragm 150, light spots are reduced, and the image contrast is improved; and the projection equipment 1 has lower transmittance, realizes the short-distance projection of large images and has high imaging quality.

The above embodiments are merely examples and are not intended to limit the scope of the present disclosure, and all modifications, equivalents, and flow charts using the contents of the specification and drawings are included in the scope of the present disclosure.

Claims (10)

1. A short focus projection lens, comprising:

an optical lens group for imaging the microimages into a projected image; the optical lens group comprises a first lens group and a second lens group, and the first lens group is used for imaging the microimage into an intermediate image; the second lens group is used for imaging the intermediate image into the projection image;

the diaphragm is arranged between the first lens group and the second lens group, and the diaphragm, the first lens group and the second lens group have the same main optical axis;

wherein the offset of the projected image relative to the main optical axis is 180% -200%.

2. The short focus projection lens of claim 1 wherein the first lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; the first lens, the third lens and the fourth lens are biconvex lenses, the fifth lens is a biconcave lens, the sixth lens is a positive crescent lens, and the second lens is a negative crescent lens.

3. The short-focus projection lens of claim 2, wherein the fifth lens and the sixth lens are cemented into a whole.

4. The short focus projection lens of any of claims 1-3 wherein the second lens group comprises a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, and a fourteenth lens; the ninth lens and the fourteenth lens are aspheric lenses, the tenth lens is a double convex lens, the seventh lens and the eighth lens are positive meniscus lenses, and the eleventh lens, the twelfth lens and the thirteenth lens are negative meniscus lenses; the aspheric lens is an even-order aspheric lens.

5. The short focus projection lens of claim 4 wherein the tenth lens and the eleventh lens are cemented together as a single unit.

6. The short-focus projection lens of claim 1, wherein the throw ratio of the short-focus projection lens is 0.6-0.8.

7. The short-focus projection lens of claim 1, wherein the short-focus projection lens has an effective focal length of 5.1mm, a relative aperture of 1.7, a maximum aperture of less than 70mm, an optical total length of 113mm, and a telecentricity of less than 1 °.

8. The short-focus projection lens of claim 4, wherein the fourteenth lens element is made of plastic.

9. A projection device, comprising: the display chip is used for displaying micro images and serves as an object plane of the short-focus projection lens; wherein the short focus projection lens is according to any one of claims 1-8.

10. The projection device of claim 9, wherein the display chip is a digital micromirror device; the digital micromirror device is 0.33 inches, and the resolution of the digital micromirror device is 1368 x 768.

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