TWI629529B - Projector and projection lens - Google Patents

Abstract

A projector and a projection lens. The projection lens includes a first lens group, a second lens group, and a third lens group which are sequentially arranged from the screen end to the light valve end. The first lens group has a negative refractive power, and includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, which have negative, negative, negative, positive, and negative diopters, respectively. The second lens group has a positive refractive power, and includes a sixth lens and a seventh lens with positive and positive refractive powers, respectively. The third lens group has a positive refractive power, and includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens that have negative, positive, negative, positive, negative, positive, and positive diopters, respectively. lens. The projector has good imaging quality, and the projection lens has good optical quality.

Description

Projector and projection lens

The present invention relates to a projection lens, and more particularly to a projection lens for a projector.

In today's tight space utilization environment, such as in a small office, when a large-sized display screen is required, a projector capable of short-distance projection becomes quite practical.

However, the projection lenses currently used in short-focus projectors still have many problems to be overcome. Poor design of the projection lens causes problems such as increased assembly difficulty, increased material and production costs, and the inability of large-sized projection images to have clear resolution. Therefore, how to improve the above problems is the focus of attention of those in the field.

This "prior art" paragraph is only used to help understand the content of the present invention, so the content disclosed in the "prior art" may include some conventional technologies that do not constitute the ordinary knowledge of those skilled in the art. In addition, the content disclosed in the "prior art" does not represent the content or the problem to be solved by one or more embodiments of the present invention, nor does it mean that prior to the application of the present invention, it has been used by those with ordinary knowledge in the technical field to which it belongs. Know or know.

It is an object of the present invention to provide a projector having a good image resolution.

Another object of the present invention is to provide a projection lens, which has a simple structure and effectively reduces production costs.

Other objects and advantages of the present invention can be further understood from the technical features disclosed by the present invention.

In order to achieve one or a part or all of the foregoing objectives or other objectives, the present invention provides a projector including an illumination system, a light valve, and a projection lens. The lighting system is adapted to provide a lighting beam. The light valve is arranged on the transmission path of the illumination beam, and is suitable for converting the illumination beam into an image beam. The projection lens is disposed on the transmission path of the image beam and is located between the screen end and the light valve end. The projection lens includes a first lens group, a second lens group, and a third lens group. The first lens group is disposed between the screen end and the light valve end, has a negative refractive power, and includes a first lens, a second lens, a third lens, a fourth lens, and a first lens which are sequentially arranged from the screen end to the light valve end. Five lenses. The diopters of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are respectively negative, negative, negative, positive, and negative. The second lens group is disposed between the first lens group and the light valve end, has a positive refractive power, and includes a sixth lens and a seventh lens which are sequentially arranged from the screen end to the light valve end. The refractive powers of the sixth lens and the seventh lens are positive and positive, respectively. The third lens group is disposed between the second lens group and the light valve end, has a positive refractive power, and includes an eighth lens, a ninth lens, a tenth lens, and an eleventh lens, which are sequentially arranged from the screen end to the light valve end. Lens, twelfth lens, and thirteenth lens. The diopters of the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens and the thirteenth lens are respectively negative, positive, negative, negative, positive, and positive.

In order to achieve one or some or all of the above or other purposes, the present invention further provides a projection lens suitable for being disposed between the screen end and the light valve end. The projection lens includes a first lens group, a second lens group, and a third lens group. Lens group. The first lens group is disposed between the screen end and the light valve end, has a negative refractive power, and includes a first lens, a second lens, a third lens, a fourth lens, and a first lens which are sequentially arranged from the screen end to the light valve end. Five lenses. The diopters of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are respectively negative, negative, negative, positive, and negative. The second lens group is disposed between the first lens group and the light valve end, has a positive refractive power, and includes a sixth lens and a seventh lens which are sequentially arranged from the screen end to the light valve end. The refractive powers of the sixth lens and the seventh lens are positive and positive, respectively. The third lens group is disposed between the second lens group and the light valve end, has a positive refractive power, and includes an eighth lens, a ninth lens, a tenth lens, and an eleventh lens, which are sequentially arranged from the screen end to the light valve end. Lens, twelfth lens, and thirteenth lens. The diopters of the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens and the thirteenth lens are respectively negative, positive, negative, negative, positive, and positive.

In an embodiment of the projector and the projection lens of the present invention, the fourth lens and the fifth lens constitute a double cemented lens.

In an embodiment of the projector and the projection lens of the present invention, the eighth lens, the ninth lens, and the tenth lens constitute a triple cemented lens.

In an embodiment of the projector and the projection lens of the present invention, the eleventh lens and the twelfth lens constitute a double cemented lens.

In an embodiment of the projector and the projection lens of the present invention, at least one of the first lens, the second lens, and the thirteenth lens is an aspheric lens.

In an embodiment of the projector and the projection lens of the present invention, the projection lens further includes an aperture light bar, and the aperture light bar is disposed between the twelfth lens and the thirteenth lens.

In an embodiment of the projector and the projection lens of the present invention, the refractive index of the fifth lens is greater than 1.8.

In an embodiment of the projector and the projection lens of the present invention, the refractive index of the thirteenth lens is less than 1.52.

In an embodiment of the projector and the projection lens of the present invention, the effective focal length of the aforementioned projection lens is f, the effective focal length of the first lens group is f1, and 0.8 <∣f1 / f∣ <1.9.

In an embodiment of the projector and the projection lens of the present invention, the effective focal length of the above-mentioned projection lens is f, the effective focal length of the second lens group is f2, and 1.3 <∣f2 / f∣ <4.

In an embodiment of the projector and the projection lens of the present invention, the effective focal length of the above-mentioned projection lens is f, the effective focal length of the third lens group is f3, and 2.7 <∣f3 / f∣ <6.3.

In an embodiment of the projector and the projection lens of the present invention, the above-mentioned second lens group is adapted to move between the first lens group and the third lens group, and the first lens group and the light valve end have a first A distance value, a second distance value between the third lens group and the light valve end, and the first distance value and the second distance value are respectively fixed values.

In an embodiment of the projector and the projection lens of the present invention, the first lens is a convex-concave lens having a convex surface facing the screen end, the second lens is a convex-concave lens having a convex surface facing the screen end, the third lens is a biconcave lens, and the fourth lens is A meniscus lens with a concave surface facing the screen end, a fifth lens is a meniscus lens with a concave surface facing the screen end, a sixth lens is a biconvex lens, a seventh lens is a meniscus lens having a convex surface facing the screen end, an eighth lens is a meniscus lens having a convex surface facing the screen end, and a ninth lens Is a lenticular lens, the tenth lens is a convex-concave lens with a concave surface facing the screen end, the eleventh lens is a convex-concave lens with a convex surface facing the screen end, the twelfth lens is a lenticular lens, and the thirteenth lens is a lenticular lens.

In the projector according to the embodiment of the present invention, the projection lens adopts a three-group structure, that is, the first lens group, the second lens group, and the first lens group which are sequentially arranged from the screen end to the light valve end and have diopters of negative, positive, and positive, respectively. Three lens group. Under such a structural design of the projector according to the embodiment of the present invention, when the distance between the projection lens and the screen is changed to perform focusing, the first lens group and the third lens group can be kept fixed, and only the first lens group is moved. The two lens groups can achieve the purpose of focusing, so as to achieve the simple structure, low production cost, and the projection ratio can meet the requirements of short-focus design. In addition, the image projected by the projection lens according to the embodiment of the present invention has a good image resolution.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, preferred embodiments are described below in detail with reference to the accompanying drawings, as follows.

The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front, or rear, are only directions referring to the attached drawings. Therefore, the directional terms used are used to illustrate and not to limit the present invention.

FIG. 1 is a functional block diagram of a projector according to an embodiment of the present invention. As shown in FIG. 1, the projector 1 of this embodiment includes an illumination system 10, a light valve 12, and a projection lens 14. In the present embodiment, the illumination system 10 is adapted to provide an illumination beam IL1. The light valve 12 is disposed on a transmission path of the illumination light beam IL1, and the light valve 12 is adapted to convert the illumination light beam IL1 into an image light beam IL2. In this embodiment, the light valve 12 may be a Digital Micromirror Device (DMD), Liquid Crystal on Silicon (LCoS), or Liquid Crystal Display (LCD) panel, but the present invention It is not limited to this. The projection lens 14 is disposed on the transmission path of the image beam IL2, and the projection lens 14 is located between the screen end 14a and the light valve end 14b. In this embodiment, the screen end 14 a is an end remote from the light valve 12, and the light valve end 14 b is an end close to the light valve 12. In this embodiment, the illumination beam IL1 provided by the illumination system 10 can be imaged on the light valve 12 near the light valve end 14 b, and then converted into the image beam IL2 through the light valve 12, and the image beam IL2 can pass through the projection lens 14 to become (become) The projection light beam IL3 is transmitted to the screen end 14a to project an image. In this embodiment, the projection lens 14 is, for example, a fixed focus lens, but the invention is not limited thereto.

The detailed structure of the projection lens 14 of this embodiment is further described below.

FIG. 2 is a schematic structural diagram of a projection lens according to an embodiment of the present invention. As shown in FIG. 2, the projection lens 14 of this embodiment includes a first lens group 141, a second lens group 142, and a third lens group 143. In this embodiment, the first lens group 141, the second lens group 142, and the third lens group 143 are sequentially arranged along the optical axis H from the screen end 14a to the light valve end 14b. In this embodiment, the first lens group 141 is disposed between the screen end 14a and the light valve end 14b, and the first lens group 141 has a negative refractive power. In this embodiment, the second lens group 142 is disposed between the first lens group 141 and the light valve end 14b, and the second lens group 142 has a positive refractive power. In this embodiment, the third lens group 143 is disposed between the second lens group 142 and the light valve end 14b, the second lens group 142 is located between the first lens group 141 and the third lens group 143, and the third lens Group 143 has positive refractive power. The first lens group 141 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, which are sequentially arranged from the screen end 14a to the light valve end 14b. The first lens L1, The diopters of the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are respectively negative, negative, negative, positive, and negative. The second lens group 142 includes a sixth lens L6 and a seventh lens L7 which are sequentially arranged from the screen end 14a to the light valve end 14b. The refractive powers of the sixth lens L6 and the seventh lens L7 are respectively positive and positive. The third lens group 143 includes an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, and a thirteenth lens, which are sequentially arranged from the screen end 14a to the light valve end 14b. L13, in which the diopters of the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11, the twelfth lens L12, and the thirteenth lens L13 are respectively negative, positive, negative, negative, positive, and positive .

As shown in FIG. 2, in this embodiment, the first lens L1 is, for example, a convex-concave lens having a convex surface facing the screen end 14a, the second lens L2 is, for example, a convex-concave lens having a convex surface facing the screen end 14a, and the third lens L3 is, for example, a biconcave lens. The fourth lens L4 is, for example, a meniscus lens having a concave surface toward the screen end 14a, the fifth lens L5 is, for example, a convex-concave lens having a concave surface toward the screen end 14a, the sixth lens L6 is, for example, a biconvex lens, and the seventh lens L7 is, for example, a convex surface toward the screen end The convex lens 14a, the eighth lens L8 is, for example, a convex-concave lens having a convex surface facing the screen end 14a, the ninth lens L9 is, for example, a biconvex lens, the tenth lens L10 is, for example, a convex-concave lens having a concave surface facing the screen end 14a, and the eleventh lens L11 is, for example, It is a convex-concave lens with a convex surface facing the screen end 14a. The twelfth lens L12 is, for example, a biconvex lens, and the thirteenth lens L13 is, for example, a biconvex lens.

As shown in FIG. 2, in this embodiment, the projection lens 14 further includes an aperture stop 144. In this embodiment, the aperture light barrier 144 is disposed between the twelfth lens L12 and the thirteenth lens L13 of the third lens group 143. In this embodiment, the aperture light bar 144 can control the luminous flux of the image.

As shown in FIG. 2, in the present embodiment, the first lens group 141 and the light valve end 14 b have a first distance value D1. In this embodiment, the first distance value D1 is, for example, the distance value between the lens closest to the light valve end 14b and the light valve end 14b in the first lens group 141, that is, the distance between the fifth lens L5 and the light valve end 14b. The distance value between. In this embodiment, the third lens group 143 and the light valve end 14b have a second distance value D2. In this embodiment, the second distance value D2 is, for example, the distance value between the lens closest to the light valve end 14b and the light valve end 14b in the third lens group 143, that is, the thirteenth lens L13 and the light valve end 14b. The distance value. In this embodiment, the first distance value D1 and the second distance value D2 are respectively fixed values. In other words, the first lens group 141 is fixed relative to the light valve end 14b, and the third lens group 143 is fixed. It is fixed to the light valve end 14b. In addition, in the present embodiment, the first lens group 141 and the second lens group 142 have a third distance value D3. In this embodiment, the third distance value D3 is, for example, the distance value between the lens closest to the light valve end 14b in the first lens group 141 and the lens closest to the screen end 14a in the second lens group 142, that is, the first distance The distance between the five lenses L5 and the sixth lens L6. In this embodiment, a fourth distance value D4 is provided between the second lens group 142 and the third lens group 143. In this embodiment, the fourth distance value D4 is, for example, the distance between the lens closest to the light valve end 14b in the second lens group 142 and the lens closest to the screen end 14a in the third lens group 143, that is, the first distance The distance value between the seventh lens L7 and the eighth lens L8. In this embodiment, the third distance value D3 and the fourth distance value D4 are respectively adjustable values, that is, variables. That is, in this embodiment, when the projection lens 14 adjusts focus or adjusts the picture sharpness, the first lens group 141 and the third lens group 143 remain fixed, and the second lens group 142 can be moved to the first lens. Between the group 141 and the third lens group 143, the third distance value D3 and the fourth distance value D4 can be adjusted to achieve the purpose of projecting a clear projection picture.

As shown in FIG. 2, in this embodiment, the fourth lens L4 and the fifth lens L5 of the first lens group 141 constitute, for example, a double cemented lens, the eighth lens L8, the ninth lens L9 of the third lens group 143, and The tenth lens L10 is, for example, a triple cemented lens, and the eleventh lens L11 and the twelfth lens L12 of the third lens group 143 are, for example, a double cemented lens, but the present invention is not limited thereto.

The following will give an example of the parameters of the projection lens 14. However, the data listed in the tables of the following embodiments are not intended to limit the present invention. Any person with ordinary knowledge in the technical field can refer to the present invention and make appropriate changes to its parameters or settings. It still belongs to the scope of the present invention.

Table I         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> element </ td> <td> surface </ td> <td> radius of curvature (mm) </ td> <td> Pitch (mm) </ td> <td> Refractive index </ td> <td> Abbe number </ td> </ tr> <tr> <td> First Lens L1 </ td> <td> S1 </ td> <td> 462.651 </ td> <td> 6.9 </ td> <td> 1.5253 </ td> <td> 56 </ td> </ tr> <tr> <td> S2 </ td> <td> 19.585 </ td> <td> 9.04 </ td> <td> </ td> <td> </ td> </ tr> <tr> <td > Second lens L2 </ td> <td> S3 </ td> <td> 38.834 </ td> <td> 4.01 </ td> <td> 1.5253 </ td> <td> 56 </ td> < / tr> <tr> <td> S4 </ td> <td> 33.838 </ td> <td> 9.14 </ td> <td> </ td> <td> </ td> </ tr> <tr > <td> Third lens L3 </ td> <td> S5 </ td> <td> -515.731 </ td> <td> 1.83 </ td> <td> 1.8052 </ td> <td> 25.4 < / td> </ tr> <tr> <td> S6 </ td> <td> 24.198 </ td> <td> 8.39 </ td> <td> </ td> <td> </ td> </ td> tr> <tr> <td> Fourth lens L4 </ td> <td> S7 </ td> <td> -57.587 </ td> <td> 7.96 </ td> <td> 1.7408 </ td> < td> 27.8 </ td> </ tr> <tr> <td> Fifth lens L5 </ td> <td> S8 </ td> <td> -21.694 </ td> <td> 1.77 </ td> <td> 1.883 </ td> <td> 40.8 </ t d> </ tr> <tr> <td> S9 </ td> <td> -42.932 </ td> <td> 9.01 </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> Sixth lens L6 </ td> <td> S10 </ td> <td> 58.982 </ td> <td> 8.47 </ td> <td> 1.72 </ td> <td > 50.2 </ td> </ tr> <tr> <td> S11 </ td> <td> -83.65 </ td> <td> 0.47 </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> Seventh lens L7 </ td> <td> S12 </ td> <td> 47.595 </ td> <td> 5.96 </ td> <td> 1.7552 </ td> <td> 27.5 </ td> </ tr> <tr> <td> S13 </ td> <td> 258.502 </ td> <td> 13.46 </ td> <td> </ td> <td > </ td> </ tr> <tr> <td> Eighth lens L8 </ td> <td> S14 </ td> <td> 135.147 </ td> <td> 1.7 </ td> <td> 1.801 </ td> <td> 35 </ td> </ tr> <tr> <td> Ninth lens L9 </ td> <td> S15 </ td> <td> 14.418 </ td> <td> 7.2 </ td> <td> 1.4875 </ td> <td> 70.2 </ td> </ tr> <tr> <td> Tenth lens L10 </ td> <td> S16 </ td> <td> -14.418 </ td> <td> 1.3 </ td> <td> 1.7234 </ td> <td> 38 </ td> </ tr> <tr> <td> S17 </ td> <td> -79.902 </ td> <td> 0.3 </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> Eleventh lens L11 </ td> <td> S18 < / td> <td> 103.988 </ td> <td> 1.75 </ td> <td> 1.801 </ td> <td> 35 </ td> </ tr> <t r> <td> Twelfth lens L12 </ td> <td> S19 </ td> <td> 22.192 </ td> <td> 3.99 </ td> <td> 1.5163 </ td> <td> 64.1 </ td> </ tr> <tr> <td> S20 </ td> <td> -31.374 </ td> <td> 0.3 </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> Aperture light bar 144 </ td> <td> STO </ td> <td> Infinitely large </ td> <td> 1.45 </ td> <td> </ td> <td> </ td> </ tr> <tr> <td> Thirteenth lens L13 </ td> <td> S21 </ td> <td> 82.646 </ td> <td> 8 </ td> <td> 1.497 </ td> <td> 81.6 </ td> </ tr> <tr> <td> S22 </ td> <td> -25.082 </ td> <td> 27.07 </ td> <td > </ td> <td> </ td> </ tr> <tr> <td> Protective glass </ td> <td> S23 </ td> <td> Infinitely large </ td> <td> 1.05 < / td> <td> 1.51 </ td> <td> 61 </ td> </ tr> <tr> <td> S24 </ td> <td> Infinite </ td> <td> 0.7 </ td > <td> </ td> <td> </ td> </ tr> <tr> <td> Light valve end 14b </ td> <td> S25 </ td> <td> Infinitely large </ td> <td> </ td> <td> </ td> <td> </ td> </ tr> </ TBODY> </ TABLE>

In Table 1, surfaces S1 and S2 are both surfaces of the first lens L1, surfaces S3 and S4 are both surfaces of the second lens L2, surfaces S5 and S6 are both surfaces of the third lens L3, and the fourth lens L4 and the first lens L1 The five lens L5 constitutes a double cemented lens, for example, a surface S8 is a surface where the fourth lens L4 is glued to the fifth lens L5, a surface S7 is another surface of the fourth lens L4, a surface S9 is another surface of the fifth lens, and a surface S10 S11 and S11 are both surfaces of the sixth lens L6, surfaces S12 and S13 are both surfaces of the seventh lens L7, the eighth lens L8, the ninth lens L9, and the tenth lens L10 constitute a triple cemented lens, for example, and the surface S15 is an eighth lens The surface where L8 is glued to the ninth lens L9, the surface S16 is the face where the ninth lens L9 is glued to the tenth lens L10, the surface S14 is the other face of the eighth lens L8, and the surface S17 is the other face of the tenth lens L10. The eleventh lens L11 and the twelfth lens L12 constitute, for example, a double cemented lens. The surface S19 is a cemented surface of the eleventh lens L11 and the twelfth lens L12. The surface S18 is the other surface of the eleventh lens L11. The surface S20 is Is the other surface of the twelfth lens L12, and the surface STO is the aperture light Where the plane 144, the surface S21, S22 are two surfaces of the thirteenth lens. In this embodiment, the imaging surface (not shown) of the light valve 12 is located at the light valve end 14b, for example. In addition, in this embodiment, a cover glass (not shown) may be additionally provided between the light valve 12 and the thirteenth lens L13 of the third lens group 143 to cover the imaging surface of the light valve 12, The light valve 12 and its imaging surface are further protected, but the invention is not limited thereto. In Table 1, the surfaces S23 and S24 are the two surfaces of the protective glass, wherein the surface S23 is the surface of the protective glass facing the screen end 14a, and the surface S24 is the surface of the protective glass facing the light valve end 14b / light valve 12. In Table 1, the surface S25 is located at, for example, the light valve end 14b. It can also be said that the surface S25 is the plane on which the imaging surface of the light valve 12 is located. In addition, the distance in Table 1 is the linear distance between two adjacent surfaces on the optical axis H. For example, the distance between the surface S1 is the linear distance between the surface S1 of the first lens L1 and the surface S2 on the optical axis H, and the distance between the surface S2 is the surface S2 of the first lens L1 and the surface S3 of the second lens L2. The straight line distance on the axis H, and so on. In this embodiment, the refractive index of the fifth lens L3 is, for example, greater than 1.8 (as shown in Table 1, the refractive index of the fifth lens L5 is 1.883), and the refractive index of the thirteenth lens L13 is, for example, less than 1.52 (as shown in Table 1). (The refractive index of the thirteenth lens L13 shown is 1.497). In this embodiment, when the refractive index of the fifth lens L3 is greater than 1.8 and the refractive index of the thirteenth lens L13 is less than 1.52, the image frame may have good image resolution, and the image frame may not have chromatic aberration.

In this embodiment, the projection lens 14 may have two aspheric lenses. For example, in this embodiment, the first lens L1 and the second lens L2 of the first lens group 141 are, for example, aspherical lenses, and the third lens L3, the fourth lens L4, and the fifth lens of the first lens group 141 L5 is, for example, a spherical lens, and the sixth lens L6 and the seventh lens L7 of the second lens group 142 are, for example, spherical lenses, and the eighth lens L8, the ninth lens L9, the tenth lens L10, and the eleventh lens of the third lens group 143 The lens L11, the twelfth lens L12, and the thirteenth lens L13 are, for example, spherical lenses. The shapes of the surfaces S1 and S2 of the first lens L1 and the surfaces S3 and S4 of the second lens L2 in this embodiment conform to the following aspheric equations:

In the above equation, Z is the offset (sag) in the direction of the optical axis H, r is the radius of curvature near the optical axis H (such as the radius of curvature of the surfaces S1, S2, S3, and S4 in Table 1), and k is two The conic constant, c is the central curvature of the aspheric lens, and A , B , C , D , and E are aspheric coefficients. In addition, the aspherical coefficients of the first lens L1 and the second lens L2 in this embodiment are shown in Table 2.

Table II         <TABLE border = "1" borderColor = "# 000000" width = "85%"> <TBODY> <tr> <td> </ td> <td> S1 </ td> <td> S2 </ td> < td> S3 </ td> <td> S4 </ td> </ tr> <tr> <td> <i> k </ i> </ td> <td> 0 </ td> <td> -0.40928 </ td> <td> -0.10768 </ td> <td> -0.5 </ td> </ tr> <tr> <td> <i> A </ i> </ td> <td> 1.22452E- 05 </ td> <td> -2.56959E-06 </ td> <td> -7.1501E-06 </ td> <td> 1.44577E-05 </ td> </ tr> <tr> <td> <i> B </ i> </ td> <td> -2.01562E-08 </ td> <td> -4.75804E-08 </ td> <td> -2.37329E-08 </ td> <td > 1.30036E-07 </ td> </ tr> <tr> <td> <i> C </ i> </ td> <td> 2.42473E-11 </ td> <td> -1.02842E-11 </ td> <td> 3.93623E-11 </ td> <td> -7.85075E-10 </ td> </ tr> <tr> <td> <i> D </ i> </ td> < td> -1.57698E-14 </ td> <td> 5.441E-14 </ td> <td> 3.48926E-15 </ td> <td> 3.16488E-12 </ td> </ tr> <tr > <td> <i> E </ i> </ td> <td> 4.51548E-18 </ td> <td> -3.55818E-17 </ td> <td> -1.16579E-17 </ td > <td> -4.09281E-15 </ td> </ tr> </ TBODY> </ TABLE>

However, the first lens L1 and the second lens L2 of the first lens group 141 are aspheric lenses, which is only one embodiment of the present invention, and the present invention is not limited thereto. In an embodiment, the projection lens 14 is, for example, three aspheric lenses. For example, the first lens L1 and the second lens L2 of the first lens group 141 and the thirteenth lens L13 of the third lens group 143 are: Aspheric lens. In yet another embodiment, the projection lens 14 is, for example, only one aspheric lens. For example, the first lens L1 of the first lens group 141, the second lens L2, and the thirteenth lens L13 of the third lens group 143 One of them is an aspheric lens.

In the above embodiment, the material of the first lens L1 of the aspheric lens and the second lens L2 of the aspheric lens is, for example, plastic, and the material of the thirteenth lens L13 of the non-spherical lens is glass, for example. In addition, in this embodiment, the throw ratio (Throw Raito, TR) of the projection lens 14 is, for example, between 0.5 and 1.5. For example, in the embodiment in which the first lens L1 and the second lens L2 are aspherical lenses, the projection ratio of the projection lens 14 can reach 0.79; in the first lens L1, the second lens L2, and the thirteenth lens In the embodiment where L13 is an aspheric lens, the projection ratio of the projection lens 14 can reach 0.5.

In this embodiment, if the effective focal length of the projection lens 14 is f and the effective focal length of the first lens group 141 is f1, then the projection lens 14 of this embodiment conforms to the relationship: 0.8 <∣f1 / f∣ <1.9. In this embodiment, when the ratio of the effective focal length f1 of the first lens group 141 to the effective focal length f of the projection lens 14 (that is, ∣f1 / f∣) is between 0.8 and 1.9, the image projected by the projection lens 14 is With good image resolution. In this embodiment, if the effective focal length of the projection lens 14 is f and the effective focal length of the second lens group 142 is f2, then the projection lens 14 of this embodiment conforms to the relationship: 1.3 <∣f2 / f∣ <4. In this embodiment, when the ratio of the effective focal length f2 of the second lens group 142 to the effective focal length f of the projection lens 14 (ie, ∣f2 / f∣) is between 1.3 and 4, the image projected by the projection lens 14 is With good image resolution. In this embodiment, the effective focal length of the projection lens 14 is f and the effective focal length of the third lens group 143 is f3, then the projection lens 14 of this embodiment conforms to the relationship: 2.7 <∣f3 / f∣ <6.3. When the ratio of the effective focal length f3 of the three lens groups 143 to the effective focal length f of the projection lens 14 (that is, ∣f3 / f∣) is between 2.7 and 6.3, the image projected by the projection lens 14 has good image resolution. In this embodiment, the position of the light valve 12 can be ensured to be at the focal point of the third lens group 143 through the above-mentioned relational expression, so as to improve the problem of blurred image caused by the traditional design. In this embodiment, the effective focal length f of the projection lens 14 is, for example, between 11.5 and 11.8, the effective focal length f1 of the first lens group 141 is, for example, -14.25, and the effective focal length f2 of the second lens group 142 is, for example, 30.43. The effective focal length f3 of the third lens group 143 is, for example, 45.75, but the invention is not limited thereto.

3A is a field curvature diagram of a projection lens according to an embodiment of the present invention, where T is a tangential image and S is a sagittal image. FIG. 3B is a distortion diagram of a projection lens according to an embodiment of the present invention. 3C is a lateral color diagram of a projection lens according to an embodiment of the present invention. FIG. 3D is a longitudinal spherical aberration diagram of a projection lens according to an embodiment of the present invention, wherein the vertical coordinate is a pupil radius. 3E is a modulation transfer function (MTF) diagram of a projection lens according to an embodiment of the present invention, where the horizontal coordinate is a focus shift and the vertical coordinate is an optical transfer function (OTF) Modulo (modulus). In this embodiment, FIG. 3E is a diagram drawn under the condition that the spatial frequency is resolvable to 67 line pair / mm (lp / mm), but the present invention does not use This is limited. FIG. 3F is a ray fan diagram of a projection lens according to an embodiment of the present invention, in which IMA is an image height. Please refer to FIGS. 3A to 3F. In this embodiment, since the patterns shown in FIGS. 3A to 3F are all within the standard range, the projector 1 having the projection lens 14 can have good imaging quality.

To sum up, in the projector according to the embodiment of the present invention, the projection lens adopts a three-group structure, that is, the first lens group, the first lens group, the Two lens groups and a third lens group. Under such a structural design of the projector according to the embodiment of the present invention, when the distance between the projection lens and the screen is changed to perform focusing, the first lens group and the third lens group can be kept fixed, and only the first lens group is moved. The two lens groups can achieve the purpose of focusing, so as to achieve the simple structure, low production cost, and the projection ratio can meet the requirements of short-focus design. In addition, the image projected by the projection lens according to the embodiment of the present invention has a good image resolution.

However, the above are only the preferred embodiments of the present invention. When the scope of implementation of the present invention cannot be limited by this, that is, the simple equivalent changes and modifications made according to the scope of the patent application and the description of the invention, All are still within the scope of the invention patent. In addition, any embodiment of the present invention or the scope of patent application does not need to achieve all the purposes or advantages or features disclosed by the invention. In addition, the abstract and the title are only used to assist the search of patent documents, and are not intended to limit the scope of rights of the present invention. In addition, the terms "first" and "second" mentioned in this specification or the scope of the patent application are only used to name the element or to distinguish between different embodiments or ranges, not to limit the number of elements. Upper or lower limit.

1‧‧‧ projector
10‧‧‧lighting system
12‧‧‧light valve
14‧‧‧ projection lens
14a‧‧‧Screen
14b‧‧‧light valve end
141‧‧‧The first lens group
142‧‧‧Second lens group
143‧‧‧third lens group
144‧‧‧Aperture Light Bar
H‧‧‧ Optical axis
D1‧‧‧First distance value
D2‧‧‧Second distance value
D3‧‧‧ Third distance value
D4‧‧‧ Fourth distance value
IL1‧‧‧illuminating beam
IL2‧‧‧Image Beam
IL3‧‧‧ Projected Beam
L1‧‧‧First lens
L2‧‧‧Second lens
L3‧‧‧ Third lens
L4‧‧‧Fourth lens
L5‧‧‧Fifth lens
L6‧‧‧ sixth lens
L7‧‧‧ seventh lens
L8‧‧‧ Eighth lens
L9‧‧‧ Ninth lens
L10‧‧‧Tenth lens
L11‧‧‧ Eleventh lens
L12‧‧‧Twelfth lens
L13‧‧‧Thirteenth lens
S1 ~ S22‧‧‧ Surface

FIG. 1 is a functional block diagram of a projector according to an embodiment of the present invention. FIG. 2 is a schematic structural diagram of a projection lens according to an embodiment of the present invention. FIG. 3A is a field curvature diagram of a projection lens according to an embodiment of the present invention. FIG. 3B is a distortion diagram of a projection lens according to an embodiment of the present invention. 3C is a lateral color diagram of a projection lens according to an embodiment of the present invention. 3D is a longitudinal spherical aberration diagram of a projection lens according to an embodiment of the present invention. FIG. 3E is a Modulation Transfer Function (MTF) diagram of a projection lens according to an embodiment of the invention. 3F is a ray fan diagram of a projection lens according to an embodiment of the present invention.

Claims (26)

A projector includes: an illumination system adapted to provide an illumination beam; a light valve disposed on a transmission path of the illumination beam and adapted to convert the illumination beam into an image beam; and a projection lens disposed on The image beam is on a transmission path and is located between a screen end and a light valve end. The projection lens includes: a first lens group disposed between the screen end and the light valve end, and having a negative refractive power, And includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, which are sequentially arranged from the screen end to the light valve end, the first lens, the second lens, The diopters of the third lens, the fourth lens, and the fifth lens are respectively negative, negative, negative, positive, and negative; a second lens group is disposed between the first lens group and the light valve end, and Has a positive refractive power, and includes a sixth lens and a seventh lens which are sequentially arranged from the screen end to the light valve end, and the sixth lens and the seventh lens have positive diopters and positive diopters respectively; and a third Lens group, configuration The second lens group and the light valve end have a positive refractive power, and include an eighth lens, a ninth lens, a tenth lens, and a first lens which are sequentially arranged from the screen end to the light valve end. Eleven lenses, a twelfth lens, and a thirteenth lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, and the thirteenth lens They are negative, positive, negative, negative, positive, and positive. The projector according to item 1 of the patent application scope, wherein the fourth lens and the fifth lens constitute a double cemented lens. The projector according to item 1 of the scope of patent application, wherein the eighth lens, the ninth lens and the tenth lens constitute a triple cemented lens. The projector according to item 1 of the scope of patent application, wherein the eleventh lens and the twelfth lens constitute a double cemented lens. The projector according to item 1 of the scope of patent application, wherein at least one of the first lens, the second lens, and the thirteenth lens is an aspheric lens. The projector according to item 1 of the scope of patent application, wherein the projection lens further includes an aperture light bar, and the aperture light bar is disposed between the twelfth lens and the thirteenth lens. The projector according to item 1 of the scope of patent application, wherein the refractive index of the fifth lens is greater than 1.8. The projector according to item 1 of the scope of patent application, wherein the refractive index of the thirteenth lens is less than 1.52. The projector according to item 1 of the scope of patent application, wherein the effective focal length of the projection lens is f, the effective focal length of the first lens group is f1, and 0.8 <∣f1 / f∣ <1.9. The projector according to item 1 of the scope of patent application, wherein the effective focal length of the projection lens is f, the effective focal length of the second lens group is f2, and 1.3 <∣f2 / f∣ <4. The projector according to item 1 of the scope of patent application, wherein the effective focal length of the projection lens is f, the effective focal length of the third lens group is f3, and 2.7 <∣f3 / f∣ <6.3. The projector according to item 1 of the scope of patent application, wherein the second lens group is adapted to move between the first lens group and the third lens group, and the first lens group and the light valve end have A first distance value, a second distance value between the third lens group and the light valve end, and the first distance value and the second distance value are respectively a fixed value. The projector according to item 1 of the scope of patent application, wherein the first lens is a convex-concave lens having a convex surface facing the screen end, the second lens is a convex-concave lens having a convex surface facing the screen end, and the third lens is a biconcave lens. The fourth lens is a meniscus lens having a concave surface facing the screen end, the fifth lens is a meniscus lens having a concave surface facing the screen end, the sixth lens is a biconvex lens, the seventh lens is a meniscus lens having a convex surface facing the screen end, and the eighth lens is A convex-concave lens with a convex surface facing the screen end, the ninth lens is a biconvex lens, the tenth lens is a convex-concave lens with a concave surface facing the screen end, the eleventh lens is a convex-concave lens with a convex surface facing the screen end, and the twelfth lens is double A convex lens, the thirteenth lens is a lenticular lens. A projection lens is suitable for being disposed between a screen end and a light valve end. The projection lens includes: a first lens group, disposed between the screen end and the light valve end, and having a negative refractive power, including: A first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially arranged from the screen end to the light valve end, the first lens, the second lens, the first lens The diopters of the three lenses, the fourth lens, and the fifth lens are negative, negative, negative, positive, and negative respectively; a second lens group is disposed between the first lens group and the light valve end, and has a positive Diopter, and includes a sixth lens and a seventh lens arranged in order from the screen end to the light valve end, the diopters of the sixth lens and the seventh lens are positive and positive, respectively; and a third lens group Is disposed between the second lens group and the light valve end, has a positive refractive power, and includes an eighth lens, a ninth lens, and a tenth lens arranged in order from the screen end to the light valve end. , An eleventh lens, a twelfth lens, and a tenth Lens, the eighth lens, the lens of the ninth, the tenth lens, the lens eleventh, the twelfth and thirteenth lens diopter lens are negative, positive, negative, negative, positive, positive. The projection lens according to item 14 of the application, wherein the fourth lens and the fifth lens constitute a double cemented lens. The projection lens according to item 14 of the scope of patent application, wherein the eighth lens, the ninth lens, and the tenth lens constitute a triple cemented lens. The projection lens according to item 14 of the scope of patent application, wherein the eleventh lens and the twelfth lens constitute a double cemented lens. The projection lens according to item 14 of the scope of patent application, wherein at least one of the first lens, the second lens, and the thirteenth lens is an aspheric lens. The projection lens according to item 14 of the scope of patent application, further comprising an aperture light bar, which is arranged between the twelfth lens and the thirteenth lens. The projection lens according to item 14 of the scope of patent application, wherein the refractive index of the fifth lens is greater than 1.8. The projection lens according to item 14 of the scope of patent application, wherein the refractive index of the thirteenth lens is less than 1.52. The projection lens according to item 14 of the scope of patent application, wherein the effective focal length of the projection lens is f, the effective focal length of the first lens group is f1, and 0.8 <∣f1 / f∣ <1.9. The projection lens according to item 14 of the scope of the patent application, wherein the effective focal length of the projection lens is f, the effective focal length of the second lens group is f2, and 1.3 <∣f2 / f∣ <4. The projection lens according to item 14 of the scope of patent application, wherein the effective focal length of the projection lens is f, the effective focal length of the third lens group is f3, and 2.7 <∣f3 / f∣ <6.3. The projection lens according to item 14 of the scope of patent application, wherein the second lens group is adapted to be moved between the first lens group and the third lens group, and the first lens group and the light valve end have A first distance value, a second distance value between the third lens group and the light valve end, and the first distance value and the second distance value are respectively a fixed value. The projection lens according to item 14 of the scope of patent application, wherein the first lens is a convex-concave lens having a convex surface facing the screen end, the second lens is a convex-concave lens having a convex surface facing the screen end, and the third lens is a biconcave lens. The fourth lens is a meniscus lens having a concave surface facing the screen end, the fifth lens is a meniscus lens having a concave surface facing the screen end, the sixth lens is a biconvex lens, the seventh lens is a meniscus lens having a convex surface facing the screen end, and the eighth lens is A convex-concave lens with a convex surface facing the screen end, the ninth lens is a biconvex lens, the tenth lens is a convex-concave lens with a concave surface facing the screen end, the eleventh lens is a convex-concave lens with a convex surface facing the screen end, and the twelfth lens is double A convex lens, the thirteenth lens is a lenticular lens.