CN212460165U - Projection lens assembly - Google Patents

Abstract

The application discloses projection lens group, it includes along the optical axis in proper order by formation of image side to image source side: a first lens having a positive optical power; a second lens having an optical power; a third lens having a refractive power, a near-imaging side surface of which is convex; a fourth lens having a focal power, a near-imaging side of which is convex; and a fifth lens with negative focal power, the near imaging side surface of which is concave; at least one lens of the first lens to the fourth lens is a glass lens; the distance TTL from the image source surface of the projection lens group to the near imaging side surface of the first lens on the optical axis satisfies the following conditions: TTL is less than 4.8 mm; and the effective focal length f1 of the first lens and the effective focal length f3 of the third lens satisfy: 1.5 < | f3/f1| < 6.0.

Description

Projection lens assembly

Technical Field

The present application relates to the field of optical elements, and in particular, to a projection lens assembly.

Background

With the continuous upgrade of image technology, more and more customers are looking for miniaturized and portable micro-projection devices. However, most of the projection apparatuses in the market currently use a large number of projection lens groups, and the optical path design is complicated. And, therefore, the projection apparatus is also expensive, bulky, power-consuming, inconvenient to carry, and the like.

How to obtain a projection lens assembly with characteristics of miniaturization, portability, high quality, high resolution, etc. by reasonably distributing the focal power and surface type characteristics of each lens in the projection lens assembly and designing the key technical parameters of the projection lens assembly is one of the problems to be solved by many lens designs at present.

SUMMERY OF THE UTILITY MODEL

The present application provides in one aspect a projection lens assembly comprising, in order from an imaging side to an image source side along an optical axis: a first lens having a positive optical power; a second lens having an optical power; a third lens having a refractive power, a near-imaging side surface of which is convex; a fourth lens having a focal power, a near-imaging side of which is convex; and a fifth lens having a negative power, a near-image side surface of which is concave. At least one lens of the first lens to the fourth lens is a glass lens; the distance TTL from the image source surface of the projection lens group to the near imaging side surface of the first lens on the optical axis can satisfy the following conditions: TTL is less than 4.8 mm; and the effective focal length f1 of the first lens and the effective focal length f3 of the third lens satisfy: 1.5 < | f3/f1| < 6.0.

In one embodiment, the first lens element has a first lens surface and the second lens element has a second lens surface.

In one embodiment, the angle of incidence MCRA of the largest chief ray on the imaging side may satisfy: 1.2 < 1/tan (MCRA) < 2.1.

In one embodiment, the aperture value Fno of the projection lens group may satisfy: fno < 1.9.

In one embodiment, the relative illumination RI of the projection lens group can satisfy: RI is more than or equal to 36 percent.

In one embodiment, the total effective focal length f of the projection lens group and the effective focal length f5 of the fifth lens element satisfy: -2 < f/f5 < 0.

In one embodiment, a distance SAG32 on the optical axis from the intersection point of the near image source side surface of the third lens and the optical axis to the effective radius vertex of the near image source side surface of the third lens to a distance SAG42 on the optical axis from the intersection point of the near image source side surface of the fourth lens and the optical axis to the effective radius vertex of the near image source side surface of the fourth lens may satisfy: 0 < | SAG32/SAG42| < 1.5.

In one embodiment, the radius of curvature R1 of the near image side of the first lens, the radius of curvature R2 of the near image source side of the first lens, and the effective focal length f1 of the first lens may satisfy: 0.5 < (R1+ R2)/f1 < 1.5.

In one embodiment, the central thickness CT4 of the fourth lens on the optical axis and the separation distance T34 of the third lens and the fourth lens on the optical axis may satisfy: 2 < CT4/T34 < 6.

In one embodiment, the combined focal length f123 of the first lens, the second lens and the third lens and the total effective focal length f of the projection lens group can satisfy: f123/f is more than 0.9 and less than 1.6.

In one embodiment, a sum Σ AT of an axial distance TTL from an image source surface of the projection lens group to a near-image side surface of the first lens element and an axial distance between any two adjacent first to fifth lens elements may satisfy: 2 < TTL/Sigma AT < 4.

In one embodiment, a central thickness CT2 of the second lens on the optical axis, a central thickness CT3 of the third lens on the optical axis, a central thickness CT4 of the fourth lens on the optical axis, a separation distance T23 of the second lens and the third lens on the optical axis, and a separation distance T34 of the third lens and the fourth lens on the optical axis may satisfy: 2.0 < (CT2+ CT3+ CT4)/(T23+ T34) < 5.0.

In one embodiment, the central thickness CT1 of the first lens on the optical axis and the edge thickness ET1 of the first lens can satisfy: 1.5 < CT1/ET1 < 2.5.

In one embodiment, the abbe number V1 of the first lens and the abbe number V2 of the second lens may satisfy: V1-V2 > 40.

In one embodiment, the projection lens assembly further includes a stop disposed between the imaging side and the first lens.

Another aspect of the present application provides a projection lens assembly. The projection lens assembly comprises, in order from an imaging side to an image source side along an optical axis: a first lens having a positive optical power; a second lens having an optical power; a third lens having a refractive power, a near-imaging side surface of which is convex; a fourth lens having a focal power, a near-imaging side of which is convex; and a fifth lens having a negative power, a near-image side surface of which is concave. The combined focal length f123 of the second lens and the third lens and the total effective focal length f of the projection lens group meet the following conditions: f123/f is more than 0.9 and less than 1.6.

The projection lens group has at least one beneficial effect of miniaturization, small astigmatism, high brightness, high imaging quality and the like by reasonably distributing the focal power, the surface shape, the central thickness of each lens, the on-axis distance between each lens and the like of each lens.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

fig. 1 shows a schematic structural view of a projection lens group according to embodiment 1 of the present application;

fig. 2A and 2B show a relative illuminance curve and an astigmatism curve, respectively, of the projection lens group of embodiment 1;

fig. 3 is a schematic view showing the structure of a projection lens group according to embodiment 2 of the present application;

fig. 4A and 4B show the relative illuminance curve and the astigmatism curve, respectively, of the projection lens group of embodiment 2;

fig. 5 is a schematic view showing the structure of a projection lens group according to embodiment 3 of the present application;

fig. 6A and 6B show the relative illuminance curve and the astigmatism curve, respectively, of the projection lens group of embodiment 3;

fig. 7 is a schematic view showing a configuration of a projection lens group according to embodiment 4 of the present application;

fig. 8A and 8B show the relative illuminance curve and the astigmatism curve, respectively, of the projection lens group of embodiment 4;

fig. 9 is a schematic view showing the structure of a projection lens group according to embodiment 5 of the present application;

fig. 10A and 10B show the relative illuminance curve and the astigmatism curve, respectively, of the projection lens group of embodiment 5;

fig. 11 is a schematic view showing a configuration of a projection lens group according to embodiment 6 of the present application;

fig. 12A and 12B show the relative illuminance curve and the astigmatism curve, respectively, of the projection lens group of embodiment 6;

fig. 13 is a schematic view showing the structure of a projection lens group according to embodiment 7 of the present application;

fig. 14A and 14B show the relative illuminance curve and the astigmatism curve, respectively, of the projection lens group of embodiment 7;

fig. 15 is a schematic view showing the structure of a projection lens group according to embodiment 8 of the present application; and

fig. 16A and 16B show the relative illuminance curve and the astigmatism curve, respectively, of the projection lens group of embodiment 8.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

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

In the drawings, the thickness, size, and shape of the lens have been slightly exaggerated for convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and 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; 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 surface of each lens closest to the image side is referred to as the near image side of that lens, and the surface of each lens closest to the image source side is referred to as the near image source side of that lens.

It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including 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. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

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

The features, principles, and other aspects of the present application are described in detail below.

A projection lens group according to an exemplary embodiment of the present application may include five lenses having optical powers, which are a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, respectively. The five lenses are arranged in order from the image side to the image source side along the optical axis. Any adjacent two lenses of the first lens to the fifth lens can have a spacing distance therebetween.

In an exemplary embodiment, the first lens may have a positive optical power; the second lens may have a positive or negative optical power; the third lens can have positive focal power or negative focal power, and the near imaging side surface of the third lens can be a convex surface; the fourth lens can have positive focal power or negative focal power, and the near imaging side surface of the fourth lens can be a convex surface; and the fifth lens may have a negative optical power, and the near-imaging side surface thereof may be concave.

In the exemplary embodiment, through reasonable control and matching of the focal power and the surface type of each lens of the system, various aberrations of the system can be effectively balanced, and the system is ensured to have higher imaging quality.

In an exemplary embodiment, at least one of the first to fourth lenses may be a glass lens. The glass material has wider distribution of refractive index and Abbe number, wider selection range, and lower thermal expansion system of the glass, and is less influenced by the environmental temperature, so the glass material can effectively reduce the temperature drift of the projection lens and improve the thermal stability of the system when being applied to the projection lens. In addition, through reasonable matching of materials among the lenses, chromatic aberration of the system can be effectively reduced.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: TTL is less than 4.8mm, wherein TTL is the distance between the image source surface of the projection lens group and the near imaging side surface of the first lens on the optical axis. More specifically, TTL can further satisfy: TTL is less than 4.6 mm. The TTL is less than 4.8mm, and the system miniaturization can be ensured.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: 1.5 < | f3/f1| < 6.0, where f1 is the effective focal length of the first lens and f3 is the effective focal length of the third lens. Satisfying 1.5 < | f3/f1| < 6.0, being beneficial to correcting the astigmatic error of the system and balancing the image quality on a meridional image plane and a sagittal image plane.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: 1.2 < 1/tan (MCRA) < 2.1, where MCRA is the angle of incidence of the largest chief ray on the imaging side. Satisfies the requirements that 1.2 is less than 1/tan (MCRA) is less than 2.1, is beneficial to balancing the projection angle of the system and the light energy utilization rate of an image source, and is beneficial to ensuring the high resolution and uniformity of a projection imaging picture.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: fno < 1.9, wherein, Fno is the aperture value of the projection lens group. The requirement that Fno is less than 1.9 is met, the receiving capability of the lens to the light source energy is improved, and therefore the projected image with higher brightness and higher resolution is obtained.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: RI is more than or equal to 36 percent, wherein RI is the relative illumination of the projection lens group. The RI is more than or equal to 36 percent, the problems of dazzling, dark corners and the like of an imaging picture can be effectively reduced or avoided, and the higher imaging uniformity of the projection system is ensured.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: -2 < f/f5 < 0, wherein f is the total effective focal length of the projection lens group and f5 is the effective focal length of the fifth lens. More specifically, f and f5 further satisfy: -1.6 < f/f5 < 0.2. Satisfy-2 < f/f5 < 0, can control the contribution of fifth lens to system spherical aberration, make the system have higher imaging quality, still be favorable to reducing the optical dimension of system.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: 0 < | SAG32/SAG42| < 1.5, wherein SAG32 is a distance on the optical axis from an intersection point of a near-image source side surface of the third lens and the optical axis to an effective radius vertex of the near-image source side surface of the third lens, and SAG42 is a distance on the optical axis from an intersection point of a near-image source side surface of the fourth lens and the optical axis to an effective radius vertex of the near-image source side surface of the fourth lens. More specifically, SAG32 and SAG42 further may satisfy: 0.4 < | SAG32/SAG42| < 1.4. Satisfy 0 < | SAG32/SAG42| < 1.5, can effectively control the inclination of third lens and fourth lens, be favorable to correcting the astigmatic aberration of projection system, and guarantee the machinability of lens, improve production yield.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: 0.5 < (R1+ R2)/f1 < 1.5, wherein R1 is the radius of curvature of the near-image side of the first lens, R2 is the radius of curvature of the near-image source side of the first lens, and f1 is the effective focal length of the first lens. More specifically, R1, R2, and f1 may further satisfy: 0.6 < (R1+ R2)/f1 < 1.4. The optical imaging system meets the requirement that (R1+ R2)/f1 is less than 0.5, so that stray light generated by the first lens can be reduced, and the imaging quality of the optical imaging system can be improved; in addition, the total optical length of the lens is reduced, and the miniaturization of the system is realized.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: 2 < CT4/T34 < 6, where CT4 is the central thickness of the fourth lens on the optical axis, and T34 is the separation distance between the third lens and the fourth lens on the optical axis. The requirements of 2 < CT4/T34 < 6 are met, the curvature of field and distortion of the projection lens can be reduced, and the miniaturization of the system can be ensured.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: and f123/f is more than 0.9 and less than 1.6, wherein f123 is the combined focal length of the first lens, the second lens and the third lens, and f is the total effective focal length of the projection lens group. Satisfies the condition that f123/f is more than 0.9 and less than 1.6, can control the distribution of the focal power of the system, embodies the focusing characteristic of the front lens group of the projection lens, and can effectively correct the spherical aberration and astigmatism of the system.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: 2 < TTL/Σ AT < 4, where TTL is the distance on the optical axis from the image source surface of the projection lens group to the near-image side surface of the first lens element, and Σ AT is the sum of the distances on the optical axis between any two adjacent first lens elements and fifth lens elements. More specifically, TTL and Σ AT may further satisfy: 2.5 < TTL/Sigma AT < 4. The requirement that TTL/Sigma AT is more than 2 and less than 4 is met, the aberration of the projection system is favorably corrected, in addition, the assembly of each lens is favorably realized, and the projection system has better machinability.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: 2.0 < (CT2+ CT3+ CT4)/(T23+ T34) < 5.0, wherein CT2 is a central thickness of the second lens on the optical axis, CT3 is a central thickness of the third lens on the optical axis, CT4 is a central thickness of the fourth lens on the optical axis, T23 is a separation distance of the second lens and the third lens on the optical axis, and T34 is a separation distance of the third lens and the fourth lens on the optical axis. The requirement that (CT2+ CT3+ CT4)/(T23+ T34) < 5.0 is met, the off-axis aberration of the projection lens can be corrected, the ghost image intensity can be weakened, and the system has high imaging quality; in addition, the system is favorable for ensuring the assemblage and miniaturization of the system.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: 1.5 < CT1/ET1 < 2.5, where CT1 is the central thickness of the first lens on the optical axis and ET1 is the edge thickness of the first lens. More specifically, CT1 and ET1 further satisfy: 1.6 < CT1/ET1 < 2.5. The requirement that CT1/ET1 is 1.5 < CT1/ET1 < 2.5 is met, the shape of the first lens can be effectively controlled, and the first lens has processing feasibility and low forming stress.

In an exemplary embodiment, a projection lens group according to the present application may satisfy: V1-V2 > 40, where V1 is the Abbe number of the first lens and V2 is the Abbe number of the second lens. The requirement of V1-V2 > 40 can effectively reduce the chromatic aberration of the system and improve the imaging quality of the system.

In an exemplary embodiment, a projection lens group according to the present application further includes a stop disposed between the image forming side and the first lens. The diaphragm is arranged between the imaging side and the first lens, so that the matching test between the assembled projection lens group and the test equipment is facilitated, the size of the front end of the projection lens group can be reduced, and the characteristics of lightness, thinness and miniaturization of the system are met.

The projection lens group according to the above-described embodiment of the present application may employ a plurality of lenses, for example, five lenses as described above. By reasonably distributing the focal power, the surface shape, the central thickness of each lens, the on-axis distance between each lens and the like, the incident light can be effectively converged, the total length of the projection lens group is reduced, the machinability of the projection lens group is improved, the structure of each lens is more compact, the projection lens group is more beneficial to production and processing, and the practicability is higher. With the above configuration, the projection lens group according to the exemplary embodiment of the present application may have characteristics such as miniaturization, large aperture, smaller throw ratio, small astigmatism, high brightness, high resolution, and high imaging quality.

In the embodiment of the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface, that is, at least one of the near-image-side surface of the first lens to the near-image-source-side surface of the fifth lens is an aspherical mirror surface. The aspheric lens is characterized in that: the curvature varies continuously 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 better curvature radius characteristics, and has advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated during imaging can be eliminated as much as possible, thereby improving the imaging quality. Optionally, at least one of the near image side and the near source side of each of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens is an aspheric mirror surface. Optionally, each of the first, second, third, fourth, and fifth lenses has a near-image side and a near-image source side that are aspheric mirror surfaces.

However, it will be appreciated by those skilled in the art that the number of lenses constituting the projection lens group can be varied to achieve the various results and advantages described in this specification without departing from the claimed subject matter. For example, although five lenses are exemplified in the embodiment, the projection lens group is not limited to include five lenses. The projection lens assembly may also include other numbers of lenses, if desired.

Specific examples of the projection lens group applicable to the above-described embodiments are further described below with reference to the drawings.

Example 1

A projection lens group according to embodiment 1 of the present application is described below with reference to fig. 1 to 2B. Fig. 1 shows a schematic structural view of a projection lens group according to embodiment 1 of the present application.

As shown in fig. 1, the projection lens assembly sequentially comprises, from an image side to an image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and an image source surface S11.

The first lens element E1 has positive power, and its near image side S1 is convex and its near image source side S2 is concave. The second lens element E2 has positive power, and has a convex near-image side surface S3 and a concave near-image source side surface S4. The third lens element E3 has negative power, and its near image side S5 is convex and its near image source side S6 is concave. The fourth lens element E4 has positive power, and has a convex near-image side surface S7 and a convex near-image source side surface S8. The fifth lens element E5 has negative power, and its near image side S9 is concave and its near image source side S10 is concave. The light from the image source surface S11 passes through the respective surfaces S10 to S1 in order and is finally projected onto a target object (not shown) in space.

Table 1 shows a basic parameter table of the projection lens group of embodiment 1, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm).

TABLE 1

In this example, the total effective focal length f of the projection lens group is 3.41mm, the total length TTL of the projection lens group (i.e., the distance on the optical axis from the image source surface S11 of the projection lens group to the near imaging side surface S1 of the first lens E1) is 4.00mm, the half ImgH of the diagonal length of the image source surface S11 of the projection lens group is 2.32mm, the maximum half field angle Semi-FOV of the projection lens group is 38.48 °, the aperture value Fno of the projection lens group is 1.70, the relative illuminance RI of the projection lens group is 57.51%, and the incident angle MCRA of the maximum chief ray on the imaging side is 26.29 °.

In embodiment 1, the near-image-side surface and the near-image-source-side surface of any one of the first lens E1 to the fifth lens E5 are both aspheric, and the profile x of each aspheric lens can be defined by, but is not limited to, the following aspheric formula:

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is a conic coefficient; ai is the correction coefficient of the i-th order of the aspherical surface. Table 2 below shows the high-order coefficient A of each of the aspherical mirror surfaces S1 to S10 used in example 1₄、A₆、A₈、A₁₀、A₁₂、A₁₄、A₁₆、A₁₈And A₂₀。

TABLE 2

Fig. 2A shows a relative illuminance curve of the projection lens group of embodiment 1, which represents relative illuminance magnitude values corresponding to different image heights. Fig. 2B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the projection lens group of embodiment 1. As can be seen from fig. 2A and 2B, the projection lens assembly of embodiment 1 can achieve good imaging quality.

Example 2

A projection lens group according to embodiment 2 of the present application is described below with reference to fig. 3 to 4B. In this embodiment and the following embodiments, descriptions of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 3 shows a schematic structural view of a projection lens group according to embodiment 2 of the present application.

As shown in fig. 3, the projection lens assembly sequentially comprises, from the image side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and an image source surface S11.

The first lens element E1 has positive power, and its near image side S1 is convex and its near image source side S2 is concave. The second lens element E2 has positive power, and has a convex near-image side surface S3 and a concave near-image source side surface S4. The third lens element E3 has positive power, and has a convex near-image side surface S5 and a concave near-image source side surface S6. The fourth lens element E4 has positive power, and has a convex near-image side surface S7 and a convex near-image source side surface S8. The fifth lens element E5 has negative power, and its near image side S9 is concave and its near image source side S10 is concave. The light from the image source surface S11 passes through the respective surfaces S10 to S1 in order and is finally projected onto a target object (not shown) in space.

In this example, the total effective focal length f of the projection lens group is 3.22mm, the total length TTL of the projection lens group is 4.06mm, the half ImgH of the diagonal length of the image source surface S11 of the projection lens group is 2.23mm, the maximum half field angle Semi-FOV of the projection lens group is 38.50 °, the aperture value Fno of the projection lens group is 1.61, the relative illuminance RI of the projection lens group is 58.90%, and the incident angle MCRA of the maximum chief ray on the image side is 29.58 °.

Table 3 shows a basic parameter table of the projection lens group of embodiment 2, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm). Table 4 shows high-order term coefficients that can be used for each aspherical mirror surface in example 2, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 3

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

-8.3763E-03

-1.9634E-02

4.9747E-02

-1.1223E-01

1.1614E-01

-6.6159E-02

1.3433E-02

0.0000E+00

0.0000E+00

S2

-6.1945E-02

-8.4678E-03

-6.1635E-02

4.7462E-02

-6.7439E-02

9.3306E-02

-4.0878E-02

0.0000E+00

0.0000E+00

S3

-1.6299E-02

-1.1116E-01

1.4818E-01

-5.1704E-01

9.2012E-01

-5.2680E-01

8.3761E-02

0.0000E+00

0.0000E+00

S4

4.9992E-03

-7.2272E-02

2.0722E-01

-8.4628E-01

1.8033E+00

-1.6388E+00

6.4555E-01

0.0000E+00

0.0000E+00

S5

-1.5414E-01

5.5993E-02

-1.2306E-01

-1.5307E-01

4.2006E-01

-4.9906E-01

2.0901E-01

0.0000E+00

0.0000E+00

S6

-2.4089E-01

7.8285E-02

7.9325E-02

-4.4104E-01

6.0135E-01

-3.9686E-01

1.0625E-01

0.0000E+00

0.0000E+00

S7

-1.4008E-01

-6.0268E-03

3.0165E-02

-7.0187E-02

5.3253E-02

-1.7225E-02

3.3784E-03

-4.6577E-04

0.0000E+00

S8

-3.6831E-02

-5.3236E-02

6.1965E-02

-5.5432E-02

3.9480E-02

-1.6935E-02

3.7968E-03

-3.5128E-04

0.0000E+00

S9

-3.9922E-01

2.3095E-01

-2.9472E-02

-1.6251E-02

7.9834E-03

-1.5558E-03

1.4936E-04

-5.8528E-06

0.0000E+00

S10

-2.2198E-01

1.9486E-01

-1.4095E-01

7.5179E-02

-2.6267E-02

5.4786E-03

-6.1009E-04

2.7774E-05

0.0000E+00

TABLE 4

Fig. 4A shows a relative illuminance curve of the projection lens group of embodiment 2, which represents relative illuminance magnitude values corresponding to different image heights. Fig. 4B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the projection lens group of embodiment 2. As can be seen from fig. 4A and 4B, the projection lens group according to embodiment 2 can achieve good imaging quality.

Example 3

A projection lens group according to embodiment 3 of the present application is described below with reference to fig. 5 to 6B. Fig. 5 shows a schematic structural view of a projection lens group according to embodiment 3 of the present application.

As shown in fig. 5, the projection lens assembly sequentially comprises, from the image side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and an image source surface S11.

The first lens element E1 has positive power, and its near image side S1 is convex and its near image source side S2 is concave. The second lens element E2 has negative power, and has a concave near-image side surface S3 and a convex near-image source side surface S4. The third lens element E3 has positive power, and has a convex near-image side surface S5 and a convex near-image source side surface S6. The fourth lens element E4 has positive power, and has a convex near-image side surface S7 and a concave near-image source side surface S8. The fifth lens element E5 has negative power, and its near image side S9 is concave and its near image source side S10 is concave. The light from the image source surface S11 passes through the respective surfaces S10 to S1 in order and is finally projected onto a target object (not shown) in space.

In this example, the total effective focal length f of the projection lens group is 3.16mm, the total length TTL of the projection lens group is 4.39mm, the half ImgH of the diagonal length of the image source surface S11 of the projection lens group is 2.33mm, the maximum half field angle Semi-FOV of the projection lens group is 38.52 °, the aperture value Fno of the projection lens group is 1.58, the relative illuminance RI of the projection lens group is 47.44%, and the incident angle MCRA of the maximum chief ray on the image side is 29.13 °.

Table 5 shows a basic parameter table of the projection lens group of embodiment 3, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm). Table 6 shows high-order term coefficients that can be used for each aspherical mirror surface in example 3, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 5

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

-1.5325E-03

3.7433E-03

-2.8675E-02

6.9136E-02

-1.1557E-01

9.8026E-02

-3.7733E-02

0.0000E+00

0.0000E+00

S2

-1.4314E-02

-4.2637E-02

5.7035E-02

-1.9346E-01

2.4576E-01

-1.7246E-01

4.9300E-02

0.0000E+00

0.0000E+00

S3

-6.3425E-02

-4.3344E-02

2.5603E-02

-4.4207E-02

1.8648E-01

-1.5986E-01

4.5054E-02

0.0000E+00

0.0000E+00

S4

9.8986E-03

-6.3910E-02

2.6490E-01

-7.8709E-01

1.3681E+00

-1.1057E+00

3.6596E-01

0.0000E+00

0.0000E+00

S5

-1.0278E-01

9.4613E-02

-1.3096E-01

-2.3739E-01

5.6005E-01

-4.8062E-01

1.3831E-01

0.0000E+00

0.0000E+00

S6

-2.4962E-01

2.2335E-01

-1.8774E-01

-4.0133E-03

9.1807E-02

-5.7076E-02

8.8921E-03

0.0000E+00

0.0000E+00

S7

-3.7939E-02

-4.7751E-02

1.0495E-01

-1.1707E-01

7.3887E-02

-2.5678E-02

4.5483E-03

-3.1735E-04

0.0000E+00

S8

-5.0465E-02

4.1232E-03

-2.0929E-02

2.0295E-02

-7.8010E-03

1.6012E-03

-2.0317E-04

1.3600E-05

0.0000E+00

S9

-3.6186E-01

-3.5299E-02

1.9827E-01

-1.0838E-01

2.7985E-02

-3.8777E-03

2.7910E-04

-8.2540E-06

0.0000E+00

S10

1.4692E-01

-3.3413E-01

2.2348E-01

-7.9964E-02

1.7358E-02

-2.3658E-03

1.8983E-04

-6.8263E-06

0.0000E+00

TABLE 6

Fig. 6A shows a relative illuminance curve of the projection lens group of embodiment 3, which represents relative illuminance magnitude values corresponding to different image heights. Fig. 6B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the projection lens group of embodiment 3. As can be seen from fig. 6A and 6B, the projection lens group according to embodiment 3 can achieve good imaging quality.

Example 4

A projection lens group according to embodiment 4 of the present application is described below with reference to fig. 7 to 8B. Fig. 7 shows a schematic structural diagram of a projection lens group according to embodiment 4 of the present application.

As shown in fig. 7, the projection lens assembly sequentially comprises, from the image side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and an image source surface S11.

The first lens element E1 has positive power, and its near image side S1 is convex and its near image source side S2 is concave. The second lens element E2 has negative power, and its near image side S3 is convex and its near image source side S4 is concave. The third lens element E3 has positive power, and has a convex near-image side surface S5 and a convex near-image source side surface S6. The fourth lens element E4 has positive power, and has a convex near-image side surface S7 and a convex near-image source side surface S8. The fifth lens element E5 has negative power, and its near image side S9 is concave and its near image source side S10 is concave. The light from the image source surface S11 passes through the respective surfaces S10 to S1 in order and is finally projected onto a target object (not shown) in space.

In this example, the total effective focal length f of the projection lens group is 3.70mm, the total length TTL of the projection lens group is 4.54mm, the half ImgH of the diagonal length of the image source surface S11 of the projection lens group is 2.67mm, the maximum half field angle Semi-FOV of the projection lens group is 38.50 °, the aperture value Fno of the projection lens group is 1.85, the relative illumination RI of the projection lens group is 51.25%, and the incident angle MCRA of the maximum chief ray on the image side is 36.78 °.

Table 7 shows a basic parameter table of the projection lens group of embodiment 4, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm). Table 8 shows high-order term coefficients that can be used for each aspherical mirror surface in example 4, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 7

TABLE 8

Fig. 8A shows a relative illuminance curve of the projection lens group of embodiment 4, which represents relative illuminance magnitude values corresponding to different image heights. Fig. 8B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the projection lens group of embodiment 4. As can be seen from fig. 8A and 8B, the projection lens group according to embodiment 4 can achieve good imaging quality.

Example 5

A projection lens group according to embodiment 5 of the present application is described below with reference to fig. 9 to 10B. Fig. 9 shows a schematic structural view of a projection lens group according to embodiment 5 of the present application.

As shown in fig. 9, the projection lens assembly sequentially comprises, from the image side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and an image source surface S11.

The first lens element E1 has positive power, and its near image side S1 is convex and its near image source side S2 is concave. The second lens element E2 has negative power, and its near image side S3 is convex and its near image source side S4 is concave. The third lens element E3 has positive power, and has a convex near-image side surface S5 and a convex near-image source side surface S6. The fourth lens element E4 has negative power, and has a convex near-image side surface S7 and a concave near-image source side surface S8. The fifth lens element E5 has negative power, and its near image side S9 is concave and its near image source side S10 is convex. The light from the image source surface S11 passes through the respective surfaces S10 to S1 in order and is finally projected onto a target object (not shown) in space.

In this example, the total effective focal length f of the projection lens group is 3.68mm, the total length TTL of the projection lens group is 4.55mm, the half ImgH of the diagonal length of the image source surface S11 of the projection lens group is 2.75mm, the maximum half field angle Semi-FOV of the projection lens group is 38.50 °, the aperture value Fno of the projection lens group is 1.84, the relative illuminance RI of the projection lens group is 44.39%, and the incident angle MCRA of the maximum chief ray on the image side is 37.57 °.

Table 9 shows a basic parameter table of the projection lens group of embodiment 5, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm). Table 10 shows high-order term coefficients that can be used for each aspherical mirror surface in example 5, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 9

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

-1.6229E-12

4.6454E-14

-2.7287E-13

7.8285E-13

-1.1747E-12

8.8309E-13

-2.6194E-13

0.0000E+00

0.0000E+00

S2

-2.1793E-02

-6.9508E-03

-2.1151E-02

3.5242E-02

-4.4434E-02

3.0618E-02

-1.0311E-02

0.0000E+00

0.0000E+00

S3

-1.2259E-01

6.0623E-02

2.0254E-03

-7.2023E-02

2.3051E-01

-2.2080E-01

6.7006E-02

0.0000E+00

0.0000E+00

S4

-9.5155E-02

1.0090E-01

-3.3513E-02

-8.3054E-03

2.0015E-01

-2.2715E-01

8.7405E-02

0.0000E+00

0.0000E+00

S5

-4.0350E-02

1.4230E-02

-5.5992E-02

8.7226E-02

-8.4557E-02

4.6019E-02

-9.5196E-03

0.0000E+00

0.0000E+00

S6

-1.5925E-01

7.2859E-02

-8.6834E-02

6.7001E-02

-4.1359E-02

1.5711E-02

-3.1390E-03

0.0000E+00

0.0000E+00

S7

-1.4275E-01

5.9928E-03

1.7504E-03

-5.3308E-02

8.2855E-02

-6.3629E-02

2.4645E-02

-3.8090E-03

0.0000E+00

S8

-3.0970E-02

-5.1455E-03

2.0509E-03

-5.4127E-04

6.0357E-05

-3.2559E-06

8.5462E-08

-8.7952E-10

0.0000E+00

S9

-1.4609E-09

-4.4982E-15

5.5856E-15

-3.5138E-15

1.2490E-15

-2.5434E-16

2.7655E-17

-1.2429E-18

0.0000E+00

S10

1.9982E-06

-4.2323E-11

4.8945E-15

-2.2406E-15

6.5007E-16

-1.0758E-16

9.4772E-18

-3.4490E-19

0.0000E+00

Watch 10

Fig. 10A shows a relative illuminance curve of the projection lens group of embodiment 5, which represents relative illuminance magnitude values corresponding to different image heights. Fig. 10B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the projection lens group of embodiment 5. As can be seen from fig. 10A and 10B, the projection lens group according to embodiment 5 can achieve good imaging quality.

Example 6

A projection lens group according to embodiment 6 of the present application is described below with reference to fig. 11 to 12B. Fig. 11 shows a schematic structural view of a projection lens group according to embodiment 6 of the present application.

As shown in fig. 11, the projection lens assembly sequentially comprises, from the image side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and an image source surface S11.

The first lens element E1 has positive power, and its near image side S1 is convex and its near image source side S2 is concave. The second lens element E2 has negative power, and its near image side S3 is convex and its near image source side S4 is concave. The third lens element E3 has positive power, and has a convex near-image side surface S5 and a convex near-image source side surface S6. The fourth lens element E4 has positive power, and has a convex near-image side surface S7 and a convex near-image source side surface S8. The fifth lens element E5 has negative power, and its near image side S9 is concave and its near image source side S10 is concave. The light from the image source surface S11 passes through the respective surfaces S10 to S1 in order and is finally projected onto a target object (not shown) in space.

In this example, the total effective focal length f of the projection lens group is 3.57mm, the total length TTL of the projection lens group is 4.54mm, the half ImgH of the diagonal length of the image source surface S11 of the projection lens group is 2.67mm, the maximum half field angle Semi-FOV of the projection lens group is 38.50 °, the aperture value Fno of the projection lens group is 1.78, the relative illuminance RI of the projection lens group is 43.64%, and the incident angle MCRA of the maximum chief ray on the image side is 38.14 °.

Table 11 shows a basic parameter table of the projection lens group of embodiment 6, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm). Table 12 shows high-order term coefficients that can be used for each aspherical mirror surface in example 6, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 11

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

-4.8042E-08

2.4888E-11

6.1234E-14

-1.9812E-13

3.1206E-13

-2.3954E-13

7.1104E-14

0.0000E+00

0.0000E+00

S2

-1.9214E-02

2.6413E-02

-1.6809E-01

3.3880E-01

-4.0673E-01

2.4094E-01

-5.3856E-02

0.0000E+00

0.0000E+00

S3

-1.1945E-01

7.4478E-02

-1.6389E-01

2.3350E-01

2.2726E-02

-2.2554E-01

1.0501E-01

0.0000E+00

0.0000E+00

S4

-1.0845E-01

2.1039E-01

-5.9500E-01

1.5014E+00

-2.0083E+00

1.5285E+00

-4.9869E-01

0.0000E+00

0.0000E+00

S5

-1.0549E-01

7.3192E-02

-1.2482E-01

8.5087E-02

1.3704E-02

-2.8769E-02

6.7835E-03

0.0000E+00

0.0000E+00

S6

-1.3679E-01

8.0556E-02

-1.5113E-01

1.7343E-01

-1.3296E-01

6.1312E-02

-1.1783E-02

0.0000E+00

0.0000E+00

S7

-1.1172E-01

6.5610E-02

-1.6539E-01

2.3051E-01

-2.1342E-01

1.2053E-01

-3.6715E-02

4.5971E-03

0.0000E+00

S8

3.8740E-02

-1.4929E-02

1.6393E-03

-5.8915E-05

-2.2139E-06

2.5423E-07

-7.7503E-09

8.1535E-11

0.0000E+00

S9

1.8682E-02

2.2218E-05

-2.4697E-07

5.2939E-10

-5.3983E-13

-1.5396E-16

5.1394E-17

-2.4420E-18

0.0000E+00

S10

-2.3700E-02

6.7356E-03

-1.6064E-03

1.8950E-04

-1.2063E-05

4.1938E-07

-7.4587E-09

5.3012E-11

0.0000E+00

TABLE 12

Fig. 12A shows a relative illuminance curve of the projection lens group of embodiment 6, which represents relative illuminance magnitude values corresponding to different image heights. Fig. 12B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the projection lens group of embodiment 6. As can be seen from fig. 12A and 12B, the projection lens group according to embodiment 6 can achieve good imaging quality.

Example 7

A projection lens group according to embodiment 7 of the present application is described below with reference to fig. 13 to 14B. Fig. 13 is a schematic view showing the structure of a projection lens group according to embodiment 7 of the present application.

As shown in fig. 13, the projection lens assembly sequentially comprises, from the image side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and an image source surface S11.

The first lens element E1 has positive power, and its near image side S1 is convex and its near image source side S2 is concave. The second lens element E2 has negative power, and its near image side S3 is convex and its near image source side S4 is concave. The third lens element E3 has positive power, and has a convex near-image side surface S5 and a convex near-image source side surface S6. The fourth lens element E4 has positive power, and has a convex near-image side surface S7 and a convex near-image source side surface S8. The fifth lens element E5 has negative power, and its near image side S9 is concave and its near image source side S10 is concave. The light from the image source surface S11 passes through the respective surfaces S10 to S1 in order and is finally projected onto a target object (not shown) in space.

In this example, the total effective focal length f of the projection lens group is 3.43mm, the total length TTL of the projection lens group is 4.40mm, the half ImgH of the diagonal length of the image source surface S11 of the projection lens group is 2.32mm, the maximum half field angle Semi-FOV of the projection lens group is 36.70 °, the aperture value Fno of the projection lens group is 1.72, the relative illuminance RI of the projection lens group is 46.97%, and the incident angle MCRA of the maximum chief ray on the image side is 34.24 °.

Table 13 shows a basic parameter table of the projection lens group of embodiment 7, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm). Table 14 shows high-order term coefficients that can be used for each aspherical mirror surface in example 7, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

Watch 13

TABLE 14

Fig. 14A shows a relative illuminance curve of the projection lens group of embodiment 7, which represents relative illuminance magnitude values corresponding to different image heights. Fig. 14B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the projection lens group of embodiment 7. As can be seen from fig. 14A and 14B, the projection lens group according to embodiment 7 can achieve good imaging quality.

Example 8

A projection lens group according to embodiment 8 of the present application is described below with reference to fig. 15 to 16B. Fig. 15 shows a schematic structural view of a projection lens group according to embodiment 8 of the present application.

As shown in fig. 15, the projection lens group sequentially includes, from the image side to the image source side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and an image source surface S11.

The first lens element E1 has positive power, and its near image side S1 is convex and its near image source side S2 is concave. The second lens element E2 has negative power, and its near image side S3 is convex and its near image source side S4 is concave. The third lens element E3 has positive power, and has a convex near-image side surface S5 and a convex near-image source side surface S6. The fourth lens element E4 has positive power, and has a convex near-image side surface S7 and a convex near-image source side surface S8. The fifth lens element E5 has negative power, and its near image side S9 is concave and its near image source side S10 is concave. The light from the image source surface S11 passes through the respective surfaces S10 to S1 in order and is finally projected onto a target object (not shown) in space.

In this example, the total effective focal length f of the projection lens group is 3.42mm, the total length TTL of the projection lens group is 4.38mm, the half ImgH of the diagonal length of the image source surface S11 of the projection lens group is 2.32mm, the maximum half field angle Semi-FOV of the projection lens group is 36.99 °, the aperture value Fno of the projection lens group is 1.71, the relative illuminance RI of the projection lens group is 36.41%, and the incident angle MCRA of the maximum chief ray on the image side is 34.81 °.

Table 15 shows a basic parameter table of the projection lens group of embodiment 8, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm). Table 16 shows high-order term coefficients that can be used for each aspherical mirror surface in example 8, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

Watch 15

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

-6.3190E-03

-1.1420E-02

2.3685E-02

-5.9578E-02

6.0341E-02

-3.4353E-02

5.5680E-03

0.0000E+00

0.0000E+00

S2

-5.3835E-02

-9.2616E-03

-4.6750E-02

5.9120E-02

-6.8069E-02

5.0796E-02

-1.6323E-02

0.0000E+00

0.0000E+00

S3

-8.1275E-02

2.1940E-03

-3.3396E-02

2.1541E-01

-2.5223E-01

1.6944E-01

-5.2610E-02

0.0000E+00

0.0000E+00

S4

-6.3034E-02

8.5015E-02

-4.4615E-02

1.1627E-01

2.9274E-02

-1.4511E-01

1.0188E-01

0.0000E+00

0.0000E+00

S5

-9.8979E-02

1.2358E-03

-2.6892E-02

-1.2244E-01

2.3345E-01

-2.0662E-01

5.2199E-02

0.0000E+00

0.0000E+00

S6

-1.5277E-01

5.2251E-02

-8.5133E-02

8.6371E-02

-7.6161E-02

4.0709E-02

-1.1615E-02

0.0000E+00

0.0000E+00

S7

-1.2425E-01

-1.4327E-03

1.4905E-02

-5.9119E-02

8.5636E-02

-6.1357E-02

2.2950E-02

-3.4936E-03

0.0000E+00

S8

2.8487E-02

-4.7228E-02

3.2801E-02

-3.0959E-02

2.1564E-02

-7.9442E-03

1.4101E-03

-9.5680E-05

0.0000E+00

S9

-3.5261E-01

4.4735E-01

-4.0132E-01

2.3020E-01

-7.8071E-02

1.5046E-02

-1.5177E-03

6.2076E-05

0.0000E+00

S10

-1.3034E-01

1.2105E-01

-7.7645E-02

3.0194E-02

-6.9214E-03

9.0092E-04

-6.1215E-05

1.6833E-06

0.0000E+00

TABLE 16

Fig. 16A shows a relative illuminance curve of the projection lens group of embodiment 8, which represents relative illuminance magnitude values corresponding to different image heights. Fig. 16B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the projection lens group of embodiment 8. As can be seen from fig. 16A and 16B, the projection lens group according to embodiment 8 can achieve good imaging quality.

In summary, examples 1 to 8 each satisfy the relationship shown in table 17.

TABLE 17

The present application further provides a projection device, wherein the electronic photosensitive element can be a photosensitive coupled device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS) device. The projection device may be a stand-alone projection device such as a projector, or may be a projection module integrated on a mobile electronic device such as a mobile phone. The projection device is equipped with the projection lens group described above.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims (30)

1. The projection lens assembly, along the optical axis, sequentially from the image side to the image source side, comprises:

a first lens having a positive optical power;

a second lens having an optical power;

a third lens having a refractive power, a near-imaging side surface of which is convex;

a fourth lens having a focal power, a near-imaging side of which is convex; and

the fifth lens has negative focal power, and the near imaging side surface of the fifth lens is a concave surface;

at least one lens of the first lens to the fourth lens is a glass lens;

the distance TTL from the image source surface of the projection lens group to the near imaging side surface of the first lens on the optical axis satisfies the following conditions: TTL is less than 4.8 mm; and

the effective focal length f1 of the first lens and the effective focal length f3 of the third lens satisfy: 1.5 < | f3/f1| < 6.0.

2. The projection lens group of claim 1 wherein the incident angle MCRA of the maximum chief ray on the image side satisfies: 1.2 < 1/tan (MCRA) < 2.1.

3. The projection lens group of claim 1 wherein the aperture value Fno of the projection lens group satisfies: fno < 1.9.

4. The projection lens group of claim 1 wherein the relative illumination RI of the projection lens group satisfies: RI is more than or equal to 36 percent.

5. The projection lens group of claim 1 wherein the total effective focal length f of the projection lens group and the effective focal length f5 of the fifth lens satisfy: -2 < f/f5 < 0.

6. The projection lens group of claim 1 wherein a distance SAG32 on the optical axis from an intersection point of the near-image-source-side surface of the third lens and the optical axis to an effective radius vertex of the near-image-source-side surface of the third lens to a distance SAG42 on the optical axis from an intersection point of the near-image-source-side surface of the fourth lens and the optical axis to an effective radius vertex of the near-image-source-side surface of the fourth lens satisfies: 0 < | SAG32/SAG42| < 1.5.

7. The projection lens group of claim 1 wherein the radius of curvature of the near image side of the first lens, R1, R2, and f1 satisfy: 0.5 < (R1+ R2)/f1 < 1.5.

8. The projection lens group of claim 1 wherein the central thickness CT4 of the fourth lens on the optical axis is separated from the third lens and the fourth lens on the optical axis by a distance T34 that satisfies: 2 < CT4/T34 < 6.

9. The projection lens group of claim 1 wherein the combined focal length f123 of the first, second and third lenses and the total effective focal length f of the projection lens group satisfy: f123/f is more than 0.9 and less than 1.6.

10. The projection lens group of claim 1 wherein the sum of the distance TTL on the optical axis from the image source surface of the projection lens group to the near-image side surface of the first lens element and the distance Σ AT between any two adjacent lens elements of the first lens element to the fifth lens element on the optical axis satisfies: 2 < TTL/Sigma AT < 4.

11. The projection lens group of claim 1 wherein a center thickness CT2 of the second lens on the optical axis, a center thickness CT3 of the third lens on the optical axis, a center thickness CT4 of the fourth lens on the optical axis, a separation distance T23 of the second lens and the third lens on the optical axis, and a separation distance T34 of the third lens and the fourth lens on the optical axis satisfy: 2.0 < (CT2+ CT3+ CT4)/(T23+ T34) < 5.0.

12. The projection lens group of claim 1 wherein the center thickness CT1 of the first lens on the optical axis and the edge thickness ET1 of the first lens satisfy: 1.5 < CT1/ET1 < 2.5.

13. The projection lens group of claim 1 wherein the abbe number V1 of the first lens and the abbe number V2 of the second lens satisfy: V1-V2 > 40.

14. The projection lens assembly of claim 1 further comprising a stop disposed between the imaging side and the first lens.

15. The projection lens assembly, along the optical axis, sequentially from the image side to the image source side, comprises:

a first lens having a positive optical power;

a second lens having an optical power;

a third lens having a refractive power, a near-imaging side surface of which is convex;

a fourth lens having a focal power, a near-imaging side of which is convex; and

the fifth lens has negative focal power, and the near imaging side surface of the fifth lens is a concave surface;

the combined focal length f123 of the first lens, the second lens and the third lens and the total effective focal length f of the projection lens group satisfy: f123/f is more than 0.9 and less than 1.6.

16. The projection lens group of claim 15, wherein at least one of the first lens to the fourth lens is a glass lens.

17. The projection lens group of claim 15 wherein the distance TTL between the image source surface of the projection lens group and the near imaging side surface of the first lens on the optical axis satisfies: TTL is less than 4.8 mm.

18. The projection lens group of claim 15 wherein the effective focal length f1 of the first lens and the effective focal length f3 of the third lens satisfy: 1.5 < | f3/f1| < 6.0.

19. The projection lens group of claim 15 wherein the incident angle MCRA of the maximum chief ray on the image side satisfies: 1.2 < 1/tan (MCRA) < 2.1.

20. The projection lens group of claim 15 wherein the aperture value Fno of the projection lens group satisfies: fno < 1.9.

21. The projection lens group of claim 15 wherein the relative illumination RI of the projection lens group satisfies: RI is more than or equal to 36 percent.

22. The projection lens group of claim 15 wherein the total effective focal length f of the projection lens group and the effective focal length f5 of the fifth lens satisfy: -2 < f/f5 < 0.

23. The projection lens group of claim 15 wherein a distance SAG32 on the optical axis from an intersection point of the near-image-source-side surface of the third lens and the optical axis to an effective radius vertex of the near-image-source-side surface of the third lens to a distance SAG42 on the optical axis from an intersection point of the near-image-source-side surface of the fourth lens and the optical axis to an effective radius vertex of the near-image-source-side surface of the fourth lens satisfies: 0 < | SAG32/SAG42| < 1.5.

24. The projection lens group of claim 15 wherein the radius of curvature R1 of the near image side of the first lens, the radius of curvature R2 of the near image source side of the first lens, and the effective focal length f1 of the first lens satisfy: 0.5 < (R1+ R2)/f1 < 1.5.

25. The projection lens group of claim 15 wherein the central thickness CT4 of the fourth lens on the optical axis is separated from the third and fourth lenses on the optical axis by a distance T34 that satisfies: 2 < CT4/T34 < 6.

26. The projection lens group of claim 15 wherein the sum of the distance TTL on the optical axis from the image source surface of the projection lens group to the near-image side surface of the first lens element and the distance Σ AT between any two adjacent lens elements of the first lens element to the fifth lens element on the optical axis satisfies: 2 < TTL/Sigma AT < 4.

27. The projection lens group of claim 15 wherein a center thickness CT2 of the second lens on the optical axis, a center thickness CT3 of the third lens on the optical axis, a center thickness CT4 of the fourth lens on the optical axis, a separation distance T23 of the second lens and the third lens on the optical axis, and a separation distance T34 of the third lens and the fourth lens on the optical axis satisfy: 2.0 < (CT2+ CT3+ CT4)/(T23+ T34) < 5.0.

28. The projection lens group of claim 15 wherein the center thickness CT1 of the first lens on the optical axis and the edge thickness ET1 of the first lens satisfy: 1.5 < CT1/ET1 < 2.5.

29. The projection lens group of claim 15 wherein the abbe number V1 of the first lens and the abbe number V2 of the second lens satisfy: V1-V2 > 40.

30. The projection lens assembly of claim 15 further comprising a stop disposed between the imaging side and the first lens.

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