CN119105157A - Projection optics and waveguide display systems - Google Patents

Abstract

The invention provides a projection lens group and a waveguide display system. The projection lens group sequentially comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens from an object side to an image side, wherein the first lens is provided with positive focal power, the second lens is provided with positive focal power, the third lens is provided with negative focal power, the fourth lens is provided with negative focal power, the fifth lens is provided with positive focal power, and the focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens meet the condition that 0<1/f1+1/f2+1/f3+1/f4+1/f5 is smaller than 0.1. The invention solves the problems of high resolution, small size and high light efficiency of the projection lens group in the prior art, which are difficult to be simultaneously considered.

Description

Projection lens group and waveguide display system

Technical Field

The invention relates to the technical field of optical imaging equipment, in particular to a projection lens group and a waveguide display system.

Background

With the continued development of the field of optical imaging, various types of display devices are gradually appearing on the market. Particularly in the field of augmented reality, attention has been paid to the unique display effect thereof. The type of the augmented reality equipment is various, taking AR glasses as an example, some problems of the existing various AR glasses, such as overlarge whole volume of a projection lens group, overlarge brightness and the like, and meanwhile, the Micro LED display chip is taken as a high-brightness active light emitting chip, so that the defects of the AR glasses in volume and brightness at present are hopefully overcome, and a great deal of attention is paid.

At present, AR glasses with single green Micro LEDs as display chips are known, the product form of the AR glasses is close to that of glasses worn by daily people, the AR glasses can be worn for a long time without fatigue, and the AR glasses have high application value in the aspect of information prompt. The batch preparation technology of Micro LED chips of single red light and Shan Languang is also mature, so that the development of the projection lens group of the single red and single blue AR glasses is possible. If three RGB single-color projection lens sets are used in combination, the combination of the waveguides becomes a feasible full-color display scheme.

The waveguide color combination is usually that an image projected by an RGB three-color projection lens set is coupled into an optical waveguide lens through three coupling-in areas, and then transmitted to the same coupling-out area through total reflection pupil expansion to couple image light, and finally the full-color image is received by human eyes of a user. The projection lens group needs to ensure that the beam energy of the received image is efficiently transmitted, and needs to bear high-temperature radiation from the Micro LED display chip to maintain higher image resolution, thereby playing a role of importance. Meanwhile, if a single projection lens group can be compatible with three monochromatic display chips of RGB, the cost of the AR optical machine can be effectively reduced. In addition, how to reduce the volume of the AR ray machine while satisfying the RGB single-color projection function is also a key to obtain wider application.

That is, the projection lens assembly in the prior art has the problems of high resolution, small size and high light efficiency, which are difficult to be simultaneously combined.

Disclosure of Invention

The invention mainly aims to provide a projection lens group and a waveguide display system, which are used for solving the problems that the projection lens group in the prior art has high resolution, small size and high light efficiency and is difficult to consider.

In order to achieve the object, according to one aspect of the invention, a projection lens assembly is provided, which sequentially comprises a first lens with positive focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with negative focal power and a fifth lens with positive focal power from an object side to an image side, wherein the focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens meet the condition that 0<1/f1+1/f2+1/f3+1/f4+1/f5<0.1.

Further, the object side surface of the first lens is a convex surface, and the image side surface is a concave surface.

Further, the object side surface of the second lens is a convex surface, and the image side surface is a concave surface.

Further, the object side surface of the third lens is a convex surface, and the image side surface is a concave surface.

Further, the object side surface at the paraxial region of the fourth lens element is convex, and the image side surface is concave.

Further, the object side surface at the paraxial region of the fifth lens element is convex, and the image side surface is concave.

Further, the projection lens group further comprises a diaphragm, and the diaphragm is arranged at the object side of the first lens.

Further, the projection lens group further comprises a display chip, and the display chip is located at the image side of the fifth lens.

Further, 1.6< f/f1+f2 <2 > is satisfied among the focal length f of the projection lens set, the focal length f1 of the first lens and the focal length f2 of the second lens.

Further, the focal length f of the projection lens group and the focal length f3 of the third lens satisfy 0.5< |f3/f| <0.7.

Further, a radius of curvature R11 of the object side surface of the first lens and a radius of curvature R12 of the image side surface of the first lens satisfy 3< R12/R11<5.

Further, the curvature radius R21 of the object side surface of the second lens and the curvature radius R22 of the image side surface of the second lens satisfy 2< R22/R21<4.

Further, the radius of curvature R31 of the object side surface of the third lens and the radius of curvature R32 of the image side surface of the third lens satisfy 2.5< R31/R32<3.

Further, the curvature radius R11 of the object side surface of the first lens and the curvature radius R21 of the object side surface of the second lens satisfy 0.9< R11/R21<1.5.

Further, the radius of curvature R11 of the object side surface of the first lens and the radius of curvature R31 of the object side surface of the third lens satisfy 0.9< R11/R31<1.6.

Further, the radius of curvature R51 of the object side surface of the fifth lens and the radius of curvature R11 of the object side surface of the first lens satisfy 0.7< R51/R11<1.3.

Further, the distance T between the object side surface of the first lens and the display chip on the optical axis is 5.5mm < T <7mm.

Further, an air space AT3 between the image side surface of the third lens element and the object side surface of the fourth lens element and a distance T between the object side surface of the first lens element and the display chip on the optical axis satisfy 0.21< AT3/T <0.3.

Further, half of the HFOV's of the maximum field angle of the projection lens set satisfy 0 < HFOV < 20.

Further, the aperture value FNo of the projection lens group is 1.3< FNo <2.5.

Further, the entrance pupil diameter EPD of the projection lens group satisfies 1mm < EPD <5mm.

Further, at least one of the first lens to the fifth lens is a glass lens.

Further, V1+V2>100 is satisfied between the Abbe number V1 of the first lens and the Abbe number V2 of the second lens.

Further, the minimum value Vmin of Abbe numbers in the first to fifth lenses satisfies that Vmin <25.

Further, the maximum value Vmax of Abbe numbers in the first to fifth lenses satisfies that Vmax >40.

Further, the maximum value Nmax of refractive indexes among the first lens to the fifth lens satisfies that Nmax >1.6.

According to another aspect of the present invention, there is provided a waveguide display system, including an optical engine, the optical engine including the projection lens set described above, the optical engine being configured to emit RGB three-color light, and an optical waveguide lens having a coupling-in working area, the RGB three-color light emitted by the optical engine entering the optical waveguide lens through the coupling-in working area, and entering a human eye for imaging after being diffracted or reflected.

By applying the technical scheme, the projection lens group sequentially comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens from an object side to an image side, wherein the first lens has positive focal power, the second lens has positive focal power, the third lens has negative focal power, the fourth lens has negative focal power, and the fifth lens has positive focal power, and the focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens meet 0<1/f1+1/f2+1/f3+1/f4+1/f5<0.1.

By setting the focal power of the first lens and the second lens to be positive, the negative focal power of the third lens can be balanced, and the sensitivity of the system is reduced. The third lens has a negative power, and this arrangement can effectively correct aberrations to improve the optical performance of the system, such as spherical aberration, coma, etc. The projection lens group of the application has the advantages of high resolution, small size, high light efficiency, mass production and the like by reasonably matching the focal power of each lens and simultaneously restricting the relation between the focal lengths of each lens. Meanwhile, by restraining the relation among the focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens, the total refractive power intensity of all the lenses can be controlled, the focal power distribution can be effectively balanced, and the influence of temperature change on the system is relieved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

FIG. 1 is a schematic view of a projection lens assembly according to a first embodiment of the present invention;

Fig. 2 to 4 show an astigmatism curve, a distortion curve, and a relative illuminance curve, respectively, of the projection lens set in fig. 1;

FIG. 5 is a schematic view of a projection lens assembly according to a second embodiment of the present invention;

Fig. 6 to 8 show an astigmatism curve, a distortion curve, and a relative illuminance curve, respectively, of the projection lens set in fig. 5;

FIG. 9 shows an optical path diagram of a projection lens assembly according to a third embodiment of the present invention;

Fig. 10 to 12 show an astigmatism curve, a distortion curve, and a relative illuminance curve, respectively, of the projection lens set in fig. 9;

FIG. 13 shows an optical path diagram of a projection lens assembly according to a fourth embodiment of the present invention;

Fig. 14 to 16 show an astigmatism curve, a distortion curve, and a relative illuminance curve, respectively, of the projection lens set in fig. 13;

FIG. 17 is a schematic diagram of a fifth embodiment of the present invention;

Fig. 18 to 20 show an astigmatism curve, a distortion curve, and a relative illuminance curve, respectively, of the projection lens set in fig. 17;

Fig. 21 is a light path diagram of a projection lens group according to a sixth embodiment of the present invention;

Fig. 22 to 24 show an astigmatism curve, a distortion curve, and a relative illuminance curve, respectively, of the projection lens set in fig. 21;

FIG. 25 is a schematic diagram showing the structure of an AR device according to an alternative embodiment of the present invention;

FIG. 26 shows a schematic diagram of a waveguide color-combining display system in accordance with an alternative embodiment of the present invention;

Fig. 27 shows a schematic layout of three spatially separated coupling-in regions of an alternative embodiment of the invention.

Wherein the above figures include the following reference numerals:

STO, diaphragm, E1, first lens, S2, object side of the first lens, S3, image side of the first lens, E2, second lens, S4, object side of the second lens, S5, image side of the second lens, E3, third lens, S6, object side of the third lens, S7, image side of the third lens, E4, fourth lens, S8, object side of the fourth lens, S9, image side of the fourth lens, E5, fifth lens, S10, object side of the fifth lens, S11, image side of the fifth lens, S12, imaging surface, 1, left eye display system, 2, right eye display system, 3, space sensor, 4, calculation unit, 5, position sensor, 6, mirror holder, 7, red light, 8, green light machine, 9, blue light machine, 10, coupling-in area, 11, green light coupling-in area, 12, blue light coupling-in area, 13, light-out area, 14, optical waveguide, 15, human eye display system.

Detailed Description

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.

It is noted that 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 unless otherwise indicated.

In the present invention, unless otherwise indicated, the use of orientation terms such as "upper, lower, top, bottom" are generally with respect to the orientation shown in the drawings or with respect to the component itself in the vertical, vertical or gravitational direction, and likewise, for ease of understanding and description, "inner, outer" refer to inner, outer relative to the profile of the component itself, but such orientation terms are not intended to limit the invention.

It should be noted that in the present specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the feature. Accordingly, a first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. Specifically, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The figures are merely examples and are not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region, and if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The determination of the surface shape in the paraxial region can be performed by a determination method by a person skilled in the art by positive or negative determination of the concave-convex with R value (R means the radius of curvature of the paraxial region, and generally means the radius of curvature value on a lens database (lens data) in optical software). The object side surface is determined to be convex when the R value is positive, and the image side surface is determined to be concave when the R value is negative, and the image side surface is determined to be concave when the R value is positive, and the image side surface is determined to be convex when the R value is negative.

In order to solve the problems that the projection lens group in the prior art has high resolution, small size and high light efficiency and is difficult to consider simultaneously, the invention provides the projection lens group and a waveguide display system.

As shown in fig. 1 to 24, the projection lens assembly sequentially comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens from an object side to an image side, wherein the first lens has positive focal power, the second lens has positive focal power, the third lens has negative focal power, the fourth lens has negative focal power, and the fifth lens has positive focal power, and the focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy 0<1/f1+1/f2+1/f3+1/f4+1/f5<0.1.

By setting the focal power of the first lens and the second lens to be positive, the negative focal power of the third lens can be balanced, and the sensitivity of the system is reduced. The third lens has a negative power, and this arrangement can effectively correct aberrations to improve the optical performance of the system, such as spherical aberration, coma, etc. The projection lens group of the application has the advantages of high resolution, small size, high light efficiency, mass production and the like by reasonably matching the focal power of each lens and simultaneously restricting the relation between the focal lengths of each lens. Meanwhile, by restraining the relation among the focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens, the total refractive power intensity of all the lenses can be controlled, the focal power distribution can be effectively balanced, and the influence of temperature change on the system is relieved.

In this embodiment, the projection lens group further includes a diaphragm, and the diaphragm is disposed at an object side of the first lens. The application is beneficial to effectively converging the light rays entering the optical system by arranging the diaphragm in front of the first lens. The projection lens group also comprises a display chip, and the display chip is positioned at the image side of the fifth lens.

It should be noted that, the display chip is a Micro LED display chip, and the projection lens set of the present application is actually a projection lens set matched with an RGB three-monochrome Micro LED display chip. The object side is the side facing the optical waveguide lens, and the image side is the side facing the display chip.

In this embodiment, the object-side surface of the first lens element is convex, and the image-side surface of the first lens element is concave. The object side surface of the first lens is convex, so that a proper projection angle can be maintained. The object side surface of the second lens is a convex surface, and the image side surface is a concave surface. The third lens element has a convex object-side surface and a concave image-side surface. The object side surface of the paraxial region of the fourth lens element is convex, and the image side surface of the paraxial region of the fourth lens element is concave. The object side surface of the fifth lens element at the paraxial region is convex, and the image side surface thereof is concave. And the surfaces of the two sides of the first lens to the fifth lens are aspheric, and the aspheric surfaces are beneficial to correcting field curvature, compressing distortion and realizing high resolution. The aspherical lens is characterized in that the curvature is continuously changed from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better radius of curvature characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. At least one inflection point is arranged on the two side surfaces of the fourth lens and the image side surface of the fifth lens at the off-axis position, and the inflection point is arranged, so that the aberration is balanced, and the resolution is improved. Meanwhile, the fourth lens has negative focal power, and the fifth lens has the characteristic of positive focal power matching with negative curvature, so that the angle of the principal ray of the system on the image surface can be reduced, and the ray on the chip surface on the inner side of the lens system is telecentric, so that the overall illuminance of the system is improved, and the aberration such as curvature of field, distortion and the like is reduced.

Here, since the fourth lens element and the fifth lens element are both curved, the shapes of the surfaces of the fourth lens element and the fifth lens element will be described in the following text, respectively, referring to the shapes of the surfaces near the optical axis, for example, the object-side surface of the fourth lens element is convex, the image-side surface of the fourth lens element is concave, the object-side surface of the fourth lens element near the optical axis is convex, the image-side surface of the fifth lens element near the optical axis is concave, the object-side surface of the fifth lens element is convex, the image-side surface of the fifth lens element near the optical axis is concave, and the image-side surface of the paraxial element near the optical axis is concave.

In the embodiment, 1.6< f/f1+f2 <2 > is satisfied among the focal length f of the projection lens set, the focal length f1 of the first lens and the focal length f2 of the second lens. The focal length f of the projection lens group and the focal length f3 of the third lens meet 0.5< |f3/f| <0.7. By controlling the two relational expressions, the reasonable distribution of the focal length of the first lens and the focal length of the third lens in the system is facilitated, the total sum of the refractive power intensity of each lens is facilitated, the focal power distribution can be effectively balanced, and the influence of temperature change on the system is relieved.

In the present embodiment, the radius of curvature R11 of the object side surface of the first lens and the radius of curvature R12 of the image side surface of the first lens satisfy 3< R12/R11<5. The radius of curvature R21 of the object-side surface of the second lens and the radius of curvature R22 of the image-side surface of the second lens satisfy 2< R22/R21<4. The radius of curvature R31 of the object side surface of the third lens and the radius of curvature R32 of the image side surface of the third lens satisfy 2.5< R31/R32<3. The radius of curvature R11 of the object-side surface of the first lens and the radius of curvature R21 of the object-side surface of the second lens satisfy 0.9< R11/R21<1.5. The radius of curvature R11 of the object-side surface of the first lens and the radius of curvature R31 of the object-side surface of the third lens satisfy 0.9< R11/R31<1.6. The radius of curvature R51 of the object-side surface of the fifth lens and the radius of curvature R11 of the object-side surface of the first lens satisfy 0.7< R51/R11<1.3. By controlling the above relation, the sensitivity of temperature and tolerance in the system can be effectively reduced. The method can better balance other aberrations such as spherical aberration, coma aberration and the like except chromatic aberration, can better reduce the CRA angle of large-view-field light on an image plane, improves the light energy utilization rate of the projection lens group to the display chip, and improves the assembly qualification rate of the projection lens group.

In the embodiment, the distance T between the object side surface of the first lens and the display chip on the optical axis is 5.5mm < T <7mm. The air interval AT3 from the image side surface of the third lens to the object side surface of the fourth lens and the distance T from the object side surface of the first lens to the display chip on the optical axis satisfy 0.21< AT3/T <0.3. By restricting the conditional expression, the small size of the projection lens group is facilitated, and the total length and the radial optical effective size of the lens system can be controlled on the premise of meeting the feasibility of processing and assembling the projection lens group, so that the miniaturization is maintained, and the volume of the projection lens group is reduced.

In this embodiment, half of the HFOV's of the maximum field angle of the projection lens set satisfy 0 < HFOV < 20. The aperture value FNo of the projection lens group is 1.3< FNo <2.5. The entrance pupil diameter EPD of the projection lens group satisfies 1mm < EPD <5mm.

In the present embodiment, at least one of the first lens to the fifth lens is a glass lens. Preferably, the first lens element can be a glass lens element, and the second lens element, the third lens element, the fourth lens element and the fifth lens element are all made of plastic material. Optionally, the second lens may be a glass lens, and the first lens, the third lens, the fourth lens and the fifth lens are all made of plastic materials. Or the first lens and the second lens are all glass lenses, and the third lens, the fourth lens and the fifth lens are all made of plastic materials.

In the present embodiment, v1+v2>100 is satisfied between the abbe number V1 of the first lens and the abbe number V2 of the second lens. The minimum value Vmin of abbe numbers in the first to fifth lenses satisfies Vmin <25. The maximum value Vmax of abbe numbers in the first to fifth lenses satisfies Vmax >40. The maximum value Nmax of refractive indexes among the first lens to the fifth lens satisfies Nmax >1.6. The abbe number and the maximum value of the refractive index of each lens are reasonably restrained, so that the distribution of different lens materials in the system can be adjusted, the stability of the image quality of the lens system can be maintained under different temperature changes, the aberration such as chromatic aberration can be corrected, the projection lens group can be matched with three RGB monochromatic display chips, and the good image quality can be maintained.

Optionally, the projection lens set may further include or not include a protective glass for protecting the display chip. Preferably, the projection lens group does not contain a protective glass. Therefore, the total length of the projection lens group is further reduced, and the miniaturization is facilitated.

In some embodiments, the display wavelength of the display chip may be red light in a 600nm to 650nm wavelength band, green light in a 500nm to 1500 nm wavelength band, or blue light in a 420nm to 480nm wavelength band. The arrangement of the application enables the projection lens group to have better resolution and higher light transmission efficiency aiming at the display chips with different colors. In most cases, due to the chromatic aberration of the projection lens assembly, there is a slight difference in the optimal optical back focus of the three types of display chips, and there is a slight difference in various optical properties (such as focal length, distortion curve, astigmatism curve, etc.).

In some embodiments, the RGB three-color Micro LED display chips are equal in size, all 1.26 inches.

As shown in fig. 25 to 27, the present application further provides a waveguide display system, which includes an optical engine and an optical waveguide lens, wherein the optical engine includes the projection lens set, the optical engine is used for emitting RGB three-color light, the optical waveguide lens has a coupling working area, and the RGB three-color light emitted by the optical engine enters the optical waveguide lens through the coupling working area, and enters human eyes for imaging after being diffracted or reflected and transmitted.

As shown in fig. 25 to 27, the present application also provides an AR device, specifically, AR glasses, but is not limited thereto.

Referring to fig. 25, the ar apparatus includes the above-described waveguide display system, i.e., the left eye display system 1 and the right eye display system 2, respectively, and further includes a camera, a space sensor 3, a computing unit 4, a position sensor 5, and a frame 6. The Micro LED display chip in the optical machine of the waveguide display system displays images, the images are input into the coupling-in working area of the optical waveguide lens after passing through each lens of the projection lens group, and the images are transmitted into human eyes through series of light. The optical waveguide lens has a high transmittance to allow the user to clearly view the real world. The computing unit 4 configured in the figure may not only provide image signals to the display chip, but also communicate with cameras, the space sensor 3, the position sensor 5 in the system. The camera and the space sensor 3 can be a combination of an RGB camera, a monochrome camera, an eyeball tracking sensor and a depth camera, the RGB or monochrome camera can acquire an environment picture in a real scene, the eyeball tracking sensor can realize an eyeball tracking function, the depth camera can acquire depth information of the scene, and the functions of face recognition, gesture recognition and the like are realized. The position sensor 5 may be a combination of an accelerometer, a gyroscope, a magnetometer and a global positioning system receiver. After processing the signals from the position sensor, the computing unit 4 can more accurately superimpose the virtual picture in the real environment.

As shown in fig. 26, the present application further provides a waveguide color-combining display system, which includes a red light ray machine 7, a green light ray machine 8, a blue light ray machine 9, and an optical waveguide lens 14, wherein the optical waveguide lens 14 includes three spatially separated coupling-in areas, namely a red light coupling-in area 10, a green light coupling-in area 11, and a blue light coupling-in area 12, which are respectively matched with the light machines of RGB three colors. The display image of the RGB three single-color display chips is projected by the projection lens group in each optical machine, respectively input into the three coupling-in areas and are coupled into the optical waveguide lens 14, then the three color lights are transmitted to the same coupling-out area 13 through the total reflection pupil expansion to be coupled out of the image light, and finally the full-color image is received by the human eyes 15 of the user.

The optical waveguide lens 14 may be a single layer, or may be formed by stacking a plurality of optical waveguide lenses 14. The three spatially separated coupling-in regions may be arranged simultaneously on a single layer of the optical waveguide lens 14 or may be arranged separately on different layers of the optical waveguide lens 14. The three coupling-in regions may be spatially arranged (perpendicular to the direction of view of the surface of the optical waveguide lens 14) in a triangular arrangement a, b, or in a linear arrangement c, d, as shown in fig. 27, or in other arrangements.

Examples of specific surface types and parameters applicable to the projection lens set of the above embodiment are further described below with reference to the drawings. In the following embodiments, green light Micro LED display chips with wavelength bands of 500nm to 570nm are used as the matched light sources of the projection lens group for performance presentation.

Any one of the following embodiments one to six is applicable to all embodiments of the present application.

Example 1

As shown in fig. 1 to 4, a projection lens set according to a first embodiment of the present application is described. Fig. 1 shows an optical path diagram of a projection lens group of the first embodiment.

As shown in fig. 1, the projection lens assembly includes, in order from an object side to an image side, a stop STO, a first lens element E1, a second lens element E2, a third lens element E3, a fourth lens element E4, a fifth lens element E5 and an image plane S12.

The first lens element E1 has positive refractive power, wherein an object-side surface S2 of the first lens element is convex, and an image-side surface S3 of the first lens element is concave. The second lens element E2 has positive refractive power, wherein an object-side surface S4 of the second lens element is convex, and an image-side surface S5 of the second lens element is concave. The third lens element E3 has negative refractive power, wherein an object-side surface S6 of the third lens element is convex, and an image-side surface S7 of the third lens element is concave. The fourth lens element E4 has negative refractive power, wherein an object-side surface S8 of the fourth lens element is convex, and an image-side surface S9 of the fourth lens element is concave. The fifth lens element E5 has positive refractive power, wherein an object-side surface S10 of the fifth lens element is convex, and an image-side surface S11 of the fifth lens element is concave.

In this embodiment, the focal length f of the projection lens set is 5.91mm, the entrance pupil diameter EPD of the projection lens set is 3.9mm, the aperture value Fno of the projection lens set is 1.51, and the half of the maximum field angle HFOV of the projection lens set is 15 °.

In the present embodiment, specific numerical values of the above conditional expression are as follows ：1/f1+1/f2+1/f3+1/f4+1/f5＝0.043;f/f1+f/f2＝1.817;|f3/f|＝0.599;R12/R11＝4.834;R22/R21＝3.103;R31/R32＝2.337;R11/R21＝1.085;R11/R31＝1.079;R51/R11＝1.079;T＝6.1mm;AT3/T＝0.259;V1+V2＝109;Vmin＝20.4;Vmax＝56;Nmax＝1.69.

Table 1 shows a basic structural parameter table of a projection lens group of the first embodiment, in which the unit of radius of curvature, thickness, and focal length is millimeter (mm).

TABLE 1

In the first embodiment, the object side surface and the image side surface of any one of the first lens element E1 to the fifth lens element E5 are aspheric, and the surface shape of each aspheric lens element can be defined by, but not limited to, the following aspheric formula:

Wherein X is the relative distance between the point on the aspheric surface and the optical axis and the relative distance between the point on the aspheric surface and the intersection point on the aspheric optical axis and the tangent to the point on the aspheric optical axis, Y is the vertical distance between the point on the aspheric curve and the optical axis, R is the curvature radius, k is the cone coefficient, ai is the i-th order aspheric coefficient;

the higher order coefficients A4, A6, A8, A10, A12, A14, A16, A18 that can be used for each of the aspherical mirrors S1-S14 in example one are given in Table 2 below.

Coefficient/surface	2	3	4	5	6
						K	6.88230E-02	3.58483E+01	3.20862E-01	5.84893E+00	-8.18504E+00
A4	-4.62979E-03	1.28672E-02	2.38525E-02	-1.01599E-01	-1.63365E-01
						A6	3.83056E-03	1.81973E-03	-3.25361E-03	1.85132E-01	2.68198E-01
A8	-2.95735E-03	-7.06903E-03	-6.69764E-04	-1.88164E-01	-2.65541E-01
						A10	1.48173E-03	4.26071E-03	-6.62602E-04	1.18591E-01	1.75623E-01
A12	-4.70841E-04	-1.32368E-03	7.17939E-04	-4.64052E-02	-7.59981E-02
						A14	8.21846E-05	2.20726E-04	-2.05678E-04	1.02342E-02	1.91859E-02
A16	-5.96922E-06	-1.56599E-05	1.98412E-05	-9.62316E-04	-2.10092E-03
						A18	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00
Coefficient/surface	7	8	9	10	11
						K	-2.07928E+00	1.32635E+01	-7.83391E+00	-4.34206E+00	5.00000E+01
A4	-4.25354E-02	-9.64661E-02	-2.03989E-02	-4.78053E-02	-6.02684E-02
						A6	1.72735E-01	4.06204E-03	-2.53356E-02	2.05518E-03	-3.32518E-02
A8	-1.96019E-01	-3.54285E-02	2.77351E-02	3.89560E-02	6.35936E-02
						A10	2.08333E-01	6.25118E-02	-3.15857E-02	-5.65389E-02	-6.11851E-02
A12	-1.60192E-01	-8.07502E-02	1.68447E-02	3.40116E-02	3.27977E-02
						A14	7.12336E-02	4.88531E-02	-4.29325E-03	-9.43848E-03	-8.62431E-03
A16	-1.26348E-02	-1.22557E-02	4.22526E-04	9.92583E-04	8.66189E-04
						A18	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00

TABLE 2

Fig. 2 shows an astigmatism curve of the projection lens group of the first embodiment, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 3 shows distortion curves of the projection lens set according to the first embodiment, which represent distortion magnitude values corresponding to different angles of view. Fig. 4 shows a relative illuminance curve of the projection lens set according to the first embodiment, which represents a ratio of peripheral brightness to central brightness.

As can be seen from fig. 2 to fig. 4, the projection lens set according to the first embodiment can achieve good imaging quality.

Example two

As shown in fig. 5 to 8, a projection lens set according to a second embodiment of the present application is described. In this embodiment and the following embodiments, a description of portions similar to those of the first embodiment will be omitted for brevity. Fig. 5 shows an optical path diagram of the projection lens group of the second embodiment.

As shown in fig. 5, the projection lens assembly includes, in order from an object side to an image side, a stop STO, a first lens element E1, a second lens element E2, a third lens element E3, a fourth lens element E4, a fifth lens element E5 and an image plane S12.

The first lens element E1 has positive refractive power, wherein an object-side surface S2 of the first lens element is convex, and an image-side surface S3 of the first lens element is concave. The second lens element E2 has positive refractive power, wherein an object-side surface S4 of the second lens element is convex, and an image-side surface S5 of the second lens element is concave. The third lens element E3 has negative refractive power, wherein an object-side surface S6 of the third lens element is convex, and an image-side surface S7 of the third lens element is concave. The fourth lens element E4 has negative refractive power, wherein an object-side surface S8 of the fourth lens element is convex, and an image-side surface S9 of the fourth lens element is concave. The fifth lens element E5 has positive refractive power, wherein an object-side surface S10 of the fifth lens element is convex, and an image-side surface S11 of the fifth lens element is concave.

In this embodiment, the focal length f of the projection lens assembly is 5.92mm, the entrance pupil diameter EPD of the projection lens assembly is 3.6mm, the aperture value Fno of the projection lens assembly is 1.64, and the half of the maximum field angle HFOV of the projection lens assembly is 15 °.

In the present embodiment, specific numerical values of the above conditional expression are as follows ：1/f1+1/f2+1/f3+1/f4+1/f5＝0.046;f/f1+f/f2＝1.866;|f3/f|＝0.630;R12/R11＝4.442;R22/R21＝3.360;R31/R32＝2.252;R11/R21＝1.110;R11/R31＝1.098;R51/R11＝0.889;T＝6.1mm;AT3/T＝0.281;V1+V2＝109;Vmin＝20.4;Vmax＝56;Nmax＝1.69.

Table 3 shows a basic structural parameter table of the projection lens group of the second embodiment, in which the unit of radius of curvature, thickness, and focal length is millimeter (mm).

TABLE 3 Table 3

Table 4 shows the higher order coefficients that can be used for each aspherical mirror in embodiment two, where each aspherical surface profile can be defined by equation (1) given in embodiment one above.

Coefficient/surface	2	3	4	5	6
						K	1.79017E-01	3.77140E+01	2.84711E-01	7.87273E+00	-7.93958E+00
A4	-3.48549E-03	2.44419E-02	3.72832E-02	-9.87637E-02	-1.71130E-01
						A6	4.16147E-03	-1.54613E-02	-2.87095E-02	1.75991E-01	2.97019E-01
A8	-3.84294E-03	6.41665E-03	2.13043E-02	-1.68519E-01	-2.99362E-01
						A10	2.12210E-03	-1.94200E-03	-1.18177E-02	9.65134E-02	1.91399E-01
A12	-6.98979E-04	3.94178E-04	4.08748E-03	-3.31216E-02	-7.59006E-02
						A14	1.26159E-04	-4.01980E-05	-7.51637E-04	6.23433E-03	1.68701E-02
A16	-9.55536E-06	6.61775E-07	5.45502E-05	-4.93688E-04	-1.59725E-03
						A18	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00
Coefficient/surface	7	8	9	10	11
						K	-2.16705E+00	1.34590E+01	-7.70527E+00	-6.13255E+00	7.47304E+00
A4	-5.67655E-02	-9.78271E-02	-6.36953E-02	-1.34202E-01	-1.49599E-01
						A6	2.24264E-01	1.37473E-02	1.32019E-01	1.95252E-01	1.18066E-01
A8	-2.93912E-01	-3.00520E-02	-1.78318E-01	-1.58693E-01	-5.93112E-02
						A10	2.91001E-01	4.08926E-03	1.21850E-01	6.38347E-02	-5.26968E-03
A12	-1.90826E-01	9.53906E-03	-5.07200E-02	-1.09527E-02	1.84191E-02
						A14	7.28592E-02	-8.04591E-03	1.16298E-02	-1.15699E-04	-6.72677E-03
A16	-1.19739E-02	1.06076E-03	-1.09808E-03	1.85781E-04	7.71597E-04
						A18	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00

TABLE 4 Table 4

Fig. 6 shows an astigmatism curve of the projection lens group of the second embodiment, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 7 shows distortion curves of the projection lens set of the second embodiment, which represent distortion magnitude values corresponding to different angles of view. Fig. 8 shows a relative illuminance curve of the projection lens set of the second embodiment, which represents a ratio of peripheral brightness to central brightness.

As can be seen from fig. 6 to 8, the projection lens set according to the second embodiment can achieve good imaging quality.

Example III

As shown in fig. 9 to 12, a projection lens group of a third embodiment of the present application is described. Fig. 9 shows an optical path diagram of a projection lens group of the third embodiment.

As shown in fig. 9, the projection lens assembly includes, in order from an object side to an image side, a stop STO, a first lens element E1, a second lens element E2, a third lens element E3, a fourth lens element E4, a fifth lens element E5 and an image plane S12.

The first lens element E1 has positive refractive power, wherein an object-side surface S2 of the first lens element is convex, and an image-side surface S3 of the first lens element is concave. The second lens element E2 has positive refractive power, wherein an object-side surface S4 of the second lens element is convex, and an image-side surface S5 of the second lens element is concave. The third lens element E3 has negative refractive power, wherein an object-side surface S6 of the third lens element is convex, and an image-side surface S7 of the third lens element is concave. The fourth lens element E4 has negative refractive power, wherein an object-side surface S8 of the fourth lens element is convex, and an image-side surface S9 of the fourth lens element is concave. The fifth lens element E5 has positive refractive power, wherein an object-side surface S10 of the fifth lens element is convex, and an image-side surface S11 of the fifth lens element is concave.

In this embodiment, the focal length f of the projection lens set is 5.59mm, the entrance pupil diameter EPD of the projection lens set is 3.6mm, the aperture value Fno of the projection lens set is 1.55, and the half of the maximum field angle HFOV of the projection lens set is 16 °.

In the present embodiment, specific numerical values of the above conditional expression are as follows ：1/f1+1/f2+1/f3+1/f4+1/f5＝0.084;f/f1+f/f2＝1.735;|f3/f|＝0.622;R12/R11＝4.342;R22/R21＝3.444;R31/R32＝2.350;R11/R21＝1.156;R11/R31＝1.150;R51/R11＝0.824;T＝6.1mm;AT3/T＝0.232;V1+V2＝109;Vmin＝20.4;Vmax＝56;Nmax＝1.69.

Table 5 shows a basic structural parameter table of the projection lens group of the third embodiment, in which the unit of radius of curvature, thickness, and focal length is millimeter (mm).

TABLE 5

Table 6 shows the higher order coefficients that can be used for each aspherical mirror in the third embodiment, wherein each aspherical surface profile can be defined by the formula (1) given in the above-described embodiment one.

TABLE 6

Fig. 10 shows an astigmatism curve of the projection lens group of the third embodiment, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 11 shows distortion curves of the projection lens group of the third embodiment, which represent distortion magnitude values corresponding to different angles of view. Fig. 12 shows a relative illuminance curve of the projection lens set of the third embodiment, which represents a ratio of peripheral luminance to central luminance.

As can be seen from fig. 10 to 12, the projection lens set according to the third embodiment can achieve good imaging quality.

Example IV

As shown in fig. 13 to 16, a projection lens group of a fourth embodiment of the present application is described. Fig. 13 shows an optical path diagram of a projection lens group of the fourth embodiment.

As shown in fig. 13, the projection lens assembly includes, in order from an object side to an image side, a stop STO, a first lens element E1, a second lens element E2, a third lens element E3, a fourth lens element E4, a fifth lens element E5 and an image plane S12.

The first lens element E1 has positive refractive power, wherein an object-side surface S2 of the first lens element is convex, and an image-side surface S3 of the first lens element is concave. The second lens element E2 has positive refractive power, wherein an object-side surface S4 of the second lens element is convex, and an image-side surface S5 of the second lens element is concave. The third lens element E3 has negative refractive power, wherein an object-side surface S6 of the third lens element is convex, and an image-side surface S7 of the third lens element is concave. The fourth lens element E4 has negative refractive power, wherein an object-side surface S8 of the fourth lens element is convex, and an image-side surface S9 of the fourth lens element is concave. The fifth lens element E5 has positive refractive power, wherein an object-side surface S10 of the fifth lens element is convex, and an image-side surface S11 of the fifth lens element is concave.

In this embodiment, the focal length f of the projection lens set is 5.93mm, the entrance pupil diameter EPD of the projection lens set is 4.2mm, the aperture value Fno of the projection lens set is 1.41, and the half of the maximum field angle HFOV of the projection lens set is 15 °.

In the present embodiment, specific numerical values of the above conditional expression are as follows ：1/f1+1/f2+1/f3+1/f4+1/f5＝0.058;f/f1+f/f2＝1.816;|f3/f|＝0.623;R12/R11＝4.449;R22/R21＝3.086;R31/R32＝2.270;R11/R21＝1.135;R11/R31＝1.126;R51/R11＝1.024;T＝6.2mm;AT3/T＝0.260;V1+V2＝109;Vmin＝20.4;Vmax＝56;Nmax＝1.69.

Table 7 shows a basic structural parameter table of a projection lens group of the fourth embodiment, in which the unit of radius of curvature, thickness, and focal length is millimeter (mm).

TABLE 7

Table 8 shows the higher order coefficients that can be used for each aspherical mirror in embodiment four, where each aspherical surface profile can be defined by equation (1) given in embodiment one above.

Coefficient/surface	2	3	4	5	6
						K	5.20204E-02	3.76188E+01	6.82526E-01	7.40378E+00	-9.23882E+00
A4	-4.40448E-03	1.96403E-02	3.33236E-02	-4.82661E-02	-1.15209E-01
						A6	4.27412E-03	-1.47964E-02	-2.75415E-02	5.73322E-02	1.35287E-01
A8	-3.34237E-03	7.08374E-03	1.71576E-02	-3.95402E-02	-8.84259E-02
						A10	1.59310E-03	-2.06357E-03	-7.25101E-03	1.98369E-02	4.10274E-02
A12	-4.40364E-04	3.15710E-04	1.96914E-03	-7.01851E-03	-1.46387E-02
						A14	6.46654E-05	-1.74953E-05	-3.08781E-04	1.43890E-03	3.40092E-03
A16	-3.88172E-06	-4.26960E-07	2.09394E-05	-1.22627E-04	-3.49288E-04
						A18	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00
Coefficient/surface	7	8	9	10	11
						K	-1.84942E+00	-9.90000E+01	-7.37855E+00	-1.40820E+01	5.00000E+01
A4	-6.36579E-02	1.57249E-02	-3.48255E-02	-2.85571E-02	-6.08353E-02
						A6	1.46739E-01	-1.78355E-01	-4.60497E-03	7.94220E-03	-2.36258E-02
A8	-1.17549E-01	2.92282E-01	2.51469E-03	-1.57103E-03	2.50951E-02
						A10	9.12744E-02	-3.56343E-01	-5.83384E-03	1.63880E-04	-1.49168E-02
A12	-5.66872E-02	2.53309E-01	1.12540E-03	-2.17548E-06	8.75853E-03
						A14	2.05510E-02	-9.78396E-02	3.78937E-04	8.43148E-07	-2.77699E-03
A16	-2.74506E-03	1.47912E-02	-9.46506E-05	-1.93798E-07	3.18252E-04
						A18	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00

TABLE 8

Fig. 14 shows an astigmatism curve of the projection lens group of the fourth embodiment, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 15 shows distortion curves of the projection lens group of the fourth embodiment, which represent distortion magnitude values corresponding to different angles of view. Fig. 16 shows a relative illuminance curve of the projection lens set of the fourth embodiment, which represents a ratio of peripheral luminance to central luminance.

As can be seen from fig. 14 to 16, the projection lens set according to the fourth embodiment can achieve good imaging quality.

Example five

As shown in fig. 17 to 20, a projection lens group of a fifth embodiment of the present application is described. Fig. 17 shows an optical path diagram of a projection lens group of the fifth embodiment.

As shown in fig. 17, the projection lens assembly includes, in order from an object side to an image side, a stop STO, a first lens element E1, a second lens element E2, a third lens element E3, a fourth lens element E4, a fifth lens element E5 and an image plane S12.

The first lens element E1 has positive refractive power, wherein an object-side surface S2 of the first lens element is convex, and an image-side surface S3 of the first lens element is concave. The second lens element E2 has positive refractive power, wherein an object-side surface S4 of the second lens element is convex, and an image-side surface S5 of the second lens element is concave. The third lens element E3 has negative refractive power, wherein an object-side surface S6 of the third lens element is convex, and an image-side surface S7 of the third lens element is concave. The fourth lens element E4 has negative refractive power, wherein an object-side surface S8 of the fourth lens element is convex, and an image-side surface S9 of the fourth lens element is concave. The fifth lens element E5 has positive refractive power, wherein an object-side surface S10 of the fifth lens element is convex, and an image-side surface S11 of the fifth lens element is concave.

In this embodiment, the focal length f of the projection lens set is 5.90mm, the entrance pupil diameter EPD of the projection lens set is 3.9mm, the aperture value Fno of the projection lens set is 1.51, and the half of the maximum field angle HFOV of the projection lens set is 15 °.

In the present embodiment, specific numerical values of the above conditional expression are as follows ：1/f1+1/f2+1/f3+1/f4+1/f5＝0.038;f/f1+f/f2＝1.866;|f3/f|＝0.605;R12/R11＝3.440;R22/R21＝3.213;R31/R32＝2.382;R11/R21＝1.220;R11/R31＝1.028;R51/R11＝1.135;T＝6.1mm;AT3/T＝0.258;V1+V2＝109;Vmin＝20.4;Vmax＝56;Nmax＝1.69.

Table 9 shows a basic structural parameter table of the projection lens group of the fifth embodiment, in which the unit of radius of curvature, thickness, and focal length is millimeter (mm).

TABLE 9

Table 10 shows the higher order coefficients that can be used for each aspherical mirror in embodiment five, where each aspherical surface profile can be defined by equation (1) given in embodiment one above.

Table 10

Fig. 18 shows an astigmatism curve of the projection lens group of the fifth embodiment, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 19 shows a distortion curve of the projection lens group of the fifth embodiment, which represents distortion magnitude values corresponding to different angles of view. Fig. 20 shows a relative illuminance curve of the projection lens set of the fifth embodiment, which represents a ratio of peripheral luminance to central luminance.

As can be seen from fig. 18 to 20, the projection lens set provided in the fifth embodiment can achieve good imaging quality.

Example six

As shown in fig. 21 to 24, a projection lens group of a sixth embodiment of the present application is described. Fig. 21 shows an optical path diagram of a projection lens group of the sixth embodiment.

As shown in fig. 21, the projection lens assembly includes, in order from an object side to an image side, a stop STO, a first lens element E1, a second lens element E2, a third lens element E3, a fourth lens element E4, a fifth lens element E5 and an image plane S12.

The first lens element E1 has positive refractive power, wherein an object-side surface S2 of the first lens element is convex, and an image-side surface S3 of the first lens element is concave. The second lens element E2 has positive refractive power, wherein an object-side surface S4 of the second lens element is convex, and an image-side surface S5 of the second lens element is concave. The third lens element E3 has negative refractive power, wherein an object-side surface S6 of the third lens element is convex, and an image-side surface S7 of the third lens element is concave. The fourth lens element E4 has negative refractive power, wherein an object-side surface S8 of the fourth lens element is convex, and an image-side surface S9 of the fourth lens element is concave. The fifth lens element E5 has positive refractive power, wherein an object-side surface S10 of the fifth lens element is convex, and an image-side surface S11 of the fifth lens element is concave.

In this embodiment, the focal length f of the projection lens set is 5.90mm, the entrance pupil diameter EPD of the projection lens set is 3.9mm, the aperture value Fno of the projection lens set is 1.51, and the half of the maximum field angle HFOV of the projection lens set is 15 °.

In the present embodiment, specific numerical values of the above conditional expression are as follows ：1/f1+1/f2+1/f3+1/f4+1/f5＝0.062;f/f1+f/f2＝1.771;|f3/f|＝0.609;R12/R11＝3.784;R22/R21＝2.762;R31/R32＝2.010;R11/R21＝1.282;R11/R31＝1.443;R51/R11＝0.987;T＝6.1mm;AT3/T＝0.260;V1+V2＝115;Vmin＝20.4;Vmax＝59.11;Nmax＝1.661.

Table 11 shows a basic structural parameter table of the projection lens group of the sixth embodiment, in which the unit of radius of curvature, thickness, and focal length is millimeter (mm).

TABLE 11

Table 12 shows the higher order coefficients that can be used for each aspherical mirror in embodiment six, where each aspherical surface profile can be defined by equation (1) given in embodiment one above.

Coefficient/surface	2	3	4	5	6
						K	2.47679E-01	3.13665E+01	1.81334E-01	1.29788E+01	-8.03268E+00
A4	-1.16085E-03	2.34151E-02	2.20758E-02	-9.39371E-02	-1.89326E-01
						A6	4.14262E-03	1.16437E-03	-7.48388E-04	1.92628E-01	3.69897E-01
A8	-2.94920E-03	-1.71003E-02	-8.69049E-03	-2.13274E-01	-4.38053E-01
						A10	8.99936E-04	1.13069E-02	3.98310E-03	1.40084E-01	3.35514E-01
A12	-1.43063E-04	-3.46664E-03	-3.61806E-04	-5.45122E-02	-1.60303E-01
						A14	1.33705E-05	5.36972E-04	-9.91029E-05	1.14647E-02	4.28192E-02
A16	-7.03797E-07	-3.44738E-05	1.50263E-05	-1.00385E-03	-4.82935E-03
						A18	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00
Coefficient/surface	7	8	9	10	11
						K	-2.12803E+00	5.70491E+00	-8.35631E+00	-1.62255E+00	-6.09985E+01
A4	-1.00685E-01	-1.37996E-01	-2.94380E-02	-9.73150E-02	-9.18128E-02
						A6	3.63365E-01	4.57116E-02	-1.09470E-03	7.84923E-02	2.24304E-02
A8	-5.19244E-01	-1.05849E-01	-1.64145E-02	-5.15954E-02	1.45674E-03
						A10	5.45949E-01	1.26530E-01	8.96763E-03	2.25605E-02	-1.30099E-02
A12	-3.68932E-01	-1.20972E-01	-4.53292E-03	-5.59351E-03	1.15377E-02
						A14	1.38938E-01	6.38820E-02	1.45650E-03	7.10944E-04	-3.72354E-03
A16	-2.03316E-02	-1.53892E-02	-1.97925E-04	-3.88209E-05	4.06135E-04
						A18	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00	0.00000E+00

Table 12

Fig. 22 shows an astigmatism curve of the projection lens group of the sixth embodiment, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 23 shows a distortion curve of the projection lens group of the sixth embodiment, which represents distortion magnitude values corresponding to different angles of view. Fig. 24 shows a relative illuminance curve of the projection lens set of the sixth embodiment, which represents a ratio of peripheral luminance to central luminance.

As can be seen from fig. 22 to 24, the projection lens set according to the sixth embodiment can achieve good imaging quality.

It will be apparent that the embodiments described above are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the application described herein may be implemented in sequences other than those illustrated or otherwise described herein.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The projection lens assembly is characterized by comprising, in order from an object side to an image side:

A first lens having positive optical power;

a second lens having positive optical power;

a third lens having negative optical power;

a fourth lens having negative optical power;

a fifth lens having positive optical power;

The focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy 0<1/f1+1/f2+1/f3+1/f4+1/f5<0.1.

2. The projection lens assembly of claim 1, wherein the first lens element has a convex object-side surface and a concave image-side surface.

3. The projection lens assembly of claim 1, wherein the second lens element has a convex object-side surface and a concave image-side surface.

4. The projection lens assembly of claim 1, wherein the third lens element has a convex object-side surface and a concave image-side surface.

5. The projection lens assembly of claim 1, wherein the object-side surface of the fourth lens element at the paraxial region is convex and the image-side surface is concave.

6. The projection lens assembly of claim 1, wherein the object-side surface of the fifth lens element at the paraxial region is convex and the image-side surface is concave.

7. The projection lens assembly of claim 1 further comprising a stop disposed to the object side of the first lens.

8. The projection lens assembly of claim 1 further comprising a display chip located on an image side of the fifth lens.

9. The projection lens group according to any one of claims 1 to 8, wherein a focal length f of the projection lens group, a focal length f1 of the first lens and a focal length f2 of the second lens satisfy 1.6< f/f1+f/f2<2.

10. A waveguide display system, comprising:

a light engine comprising the projection lens set of any one of claims 1 to 9 for emitting RGB three-color light;

The optical waveguide lens is provided with a coupling-in working area, the RGB three-color light emitted by the optical machine enters the optical waveguide lens through the coupling-in working area, and enters human eyes for imaging after diffraction or reflection transmission.