JP2019015958A - Projector and projection lens unit - Google Patents

Abstract

To provide a projector and a projection lens unit according to the present invention.SOLUTION: A projection lens unit includes a first lens group, a second lens group, and a third lens group which are arrayed in order from a screen end to an optical valve end. The first lens group has a negative refractive index, and includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens whose refractive indexes are negative, negative, negative, positive, and negative, respectively. The second lens group has a positive refractive index, and includes a sixth lens and a seventh lens whose refractive indexes are positive and positive, respectively. The third lens group has a positive refractive index, and includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens whose refractive indexes are negative, positive, negative, negative, positive, and positive, respectively. A projector instrument has superior image formation quality, and the projection lens unit has superior optical quality.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a projection lens unit, and more particularly to a projection lens unit used in a projector.

  In today's environment where space utilization is not sufficient, for example, when it is necessary to display a large screen in a narrow office room, a projector capable of short-distance projection is very useful.

  However, there are still many problems to be improved in the projection lens unit used in the current short focus projector. There are problems such as an increase in the difficulty of assembling due to a design defect of the projection lens unit, an increase in material and manufacturing cost, and a high resolution cannot be realized in a large size projection image. Therefore, it is very interesting for those skilled in the art how to improve the above problem.

  This “background art” part is intended to assist in understanding the contents of the present invention, and the contents disclosed in the “background art” part may include those that do not constitute prior art known to those skilled in the art. There is sex. The contents disclosed in the “Background” section do not indicate the contents or problems to be solved by one or more embodiments of the present invention, and the present invention has already been grasped by those skilled in the art before filing. Or does not mean that it was recognized.

  One of the objects of the present invention is to provide a projector capable of projecting an image having an excellent image analysis degree.

  Another object of the present invention is to provide a projection lens unit that has a simple structure and can effectively reduce manufacturing 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 some or all of the above objects or other objects, the present invention provides a projector including an illumination system, a light valve and a projection lens unit. The illumination system is used to provide an illumination beam. The light valve is disposed on the transmission path of the illumination light beam and is used to convert the illumination light beam into an image light beam. The projection lens unit is disposed on the transmission path of the image light flux and is positioned between the screen end and the light valve end. The projection lens unit 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 index, and is arranged in order from the screen end to the light valve end, the second lens, and the third lens , Including a fourth lens and a fifth lens. The refractive indexes of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are negative, negative, negative, positive, and negative, respectively. The second lens group is disposed between the first lens group and the light valve end, has a positive refractive index, and has a sixth lens and a seventh lens arranged in order from the screen end to the light valve end. . The refractive indexes 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 index, and is arranged in order from the screen end to the light valve end, the eighth lens, the ninth lens, A tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens. The refractive indexes of the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, and the thirteenth lens are negative, positive, negative, negative, positive, and positive, respectively.

  To achieve one or some or all of the above objects, or other objects, the present invention further provides a projection lens unit, the projection lens unit being disposed between the screen end and the light valve end, and A first lens group, a second lens group, and a third lens group are included. The first lens group is disposed between the screen end and the light valve end, has a negative refractive index, and is arranged in order from the screen end to the light valve end, a second lens, a third lens, Includes a fourth lens and a fifth lens. The refractive indexes of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are negative, negative, negative, positive, and negative, respectively. The second lens group is disposed between the first lens group and the light valve end, has a positive refractive index, and includes a sixth lens and a seventh lens arranged in order from the screen end to the light valve end. . The refractive indexes 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 bulb end, has a positive refractive index, and is arranged in order from the screen end to the light bulb end, the eighth lens, the ninth lens, and the tenth lens. A lens, an eleventh lens, a twelfth lens, and a thirteenth lens. The refractive indexes of the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, and the thirteenth lens are negative, positive, negative, negative, positive, and positive, respectively.

  In the projector according to the embodiment of the present invention, the projection lens unit employs a three-group structure, that is, is arranged in order from the screen end to the light valve end, and has a refractive index of negative, positive and positive, respectively. It includes a lens group, a second lens group, and a third lens group. The projector of the embodiment of the present invention is based on such a structural design, and when the focus is adjusted by the distance change between the projection lens unit and the screen end, the first lens group and the third lens group are fixed, Since the objective of focusing by moving only the second lens group can be achieved, the structure is simple, the manufacturing cost is relatively low, and the projection ratio can meet the needs of short focus design. The image projected by the projection lens unit according to the embodiment of the present invention has an excellent image analysis degree.

  In order to illustrate the above and other objects, features and advantages of the present invention more clearly and clearly, the following examples will be described in detail with reference to the drawings.

It is the schematic of the functional block of the projector of one Example of this invention. It is a structure schematic diagram of the projection lens unit of one Example of this invention. It is a figure which shows the field curvature of the projection lens unit of one Example of this invention. It is a figure which shows the distortion (distortion) of the projection lens unit of one Example of this invention. It is a figure which shows the lateral chromatic aberration (lateral color) of the projection lens unit of one Example of this invention. It is a figure which shows the longitudinal spherical aberration (longitudinal spherical aberration) of the projection lens unit of one Example of this invention. It is a figure which shows the modulation transfer function (Modulation Transfer Function, MTF) of the projection lens unit of one Example of this invention. It is a figure which shows the ray fan of the projection lens unit of one Example of this invention.

  The foregoing and other technical contents, features, and advantages of the present invention are clearly shown in the detailed description of the preferred embodiments with reference to the following drawings. Directional terms referred to in the following examples, such as up, down, left, right, front or back, are only directions referring to the drawings. Accordingly, these directional terms are for illustrative purposes and do not limit the invention.

  FIG. 1 is a schematic diagram of functional blocks 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 unit 14. In this embodiment, the illumination system 10 provides an illumination light beam IL1. The light valve 12 is disposed on the transmission path of the illumination light beam IL1, and the light valve 12 converts the illumination light beam IL1 into an image light beam IL2. In this embodiment, the light valve 12 may be a digital micromirror device (Digital Micromirror Device, DMD), a liquid crystal silicon substrate (Liquid Crystal on Silicon, LCoS), or a liquid crystal display (Liquid Crystal Display, LCD) panel. The present invention is not limited to these. The projection lens unit 14 is disposed on the transmission path of the image light beam IL2, and the projection lens unit 14 is located between the screen end 14a and the light valve end 14b. In this embodiment, the screen end 14 a is one end away from the light valve 12, and the light valve end 14 b is one end close to the light valve 12. In this embodiment, the illumination light beam IL1 provided by the illumination system 10 forms an image on the light valve 12 close to the light valve end 14b, and is then converted into the image light beam IL2 by the light valve 12, and the image light beam IL2 is converted into a projection lens. After passing through the unit 14, it becomes the projection light beam IL3, and the projection light beam IL3 is further transmitted to the screen end 14a to project an image. In the present embodiment, the projection lens unit 14 is a fixed focus lens unit, for example, but the present invention is not limited to this.

  Hereinafter, the detailed structure of the projection lens unit 14 of the present embodiment will be described in detail.

  FIG. 2 is a schematic structural diagram of a projection lens unit according to an embodiment of the present invention. As shown in FIG. 2, the projection lens unit 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 arranged along the optical axis H from the screen end 14a to the light valve end 14b in order. 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 index. In the present 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 index. In the present embodiment, the third lens group 143 is disposed between the second lens group 142 and the light valve end 14b, and the second lens group 142 is positioned between the first lens group 141 and the third lens group 143. In addition, the third lens group 143 has a positive refractive index. 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 arranged in order from the screen end 14a to the light valve end 14b. The refractive indexes of the one lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are negative, negative, negative, positive, and negative, respectively. The second lens group 142 includes a sixth lens L6 and a seventh lens L7 arranged in order from the screen end 14a to the light valve end 14b, and the refractive indexes of the sixth lens L6 and the seventh lens L7 are positive, Is 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 arranged in order from the screen end 14a to the light valve end 14b. And the refractive indexes 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 negative, positive, negative and negative, respectively. , Positive, positive.

  As shown in FIG. 2, in the present embodiment, the first lens L1 is, for example, a convex / concave lens having a convex surface facing the screen end 14a, and the second lens L2 is, for example, a convex / concave lens having a convex surface facing the screen end 14a. The third lens L3 is, for example, a biconcave lens, the fourth lens L4 is, for example, a concave / convex lens having a concave surface facing the screen end 14a, and the fifth lens L5 is, for example, a convex / concave lens having a concave surface facing the screen end 14a. The sixth lens L6 is, for example, a biconvex lens, the seventh lens L7 is, for example, a concave / convex lens with a convex surface facing the screen end 14a, and the eighth lens L8, for example, has a convex / concave surface with the convex surface facing the screen end 14a. The ninth lens L9, which is a lens, is a biconvex lens, for example, and the tenth lens L10 has a concave surface facing the screen end 14a, for example. The eleventh lens L11 is, for example, a convex-concave lens having 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 the present embodiment, the projection lens unit 14 further includes an aperture stop 144. In the present embodiment, the aperture stop 144 is disposed between the twelfth lens L12 and the thirteenth lens L13 of the third lens group 143. In this embodiment, the aperture stop 144 can control the density of the image light flux.

  As shown in FIG. 2, in the present embodiment, a first distance value D1 is provided between the first lens group 141 and the light valve end 14b. In the present embodiment, the first distance value D1 is, for example, the distance value between the lens closest to the light valve end 14b in the first lens group 141 and the light valve end 14b, that is, the fifth lens L5 and the light. It is a distance value between the valve end 14b. In the present embodiment, a second distance value D2 is provided between the third lens group 143 and the light valve end 14b. In the present embodiment, the second distance value D2 is, for example, a distance value between the lens closest to the light valve end 14b in the third lens group 143 and the light valve end 14b, that is, the thirteenth lens L13. It is a distance value between the light valve ends 14b. In the present embodiment, the first distance value D1 and the second distance value D2 are fixed values, in other words, the first lens group 141 is fixed so as not to move with respect to the light valve end 14b, and The third lens group 143 is fixed so as not to move with respect to the light valve end 14b. In addition, in this embodiment, a third distance value D3 is provided between the first lens group 141 and the second lens group 142. In the present 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 distance value between the fifth lens L5 and the sixth lens L6. In the present embodiment, a fourth distance value D4 is provided between the second lens group 142 and the third lens group 143. In the present embodiment, the fourth distance value D4 is, for example, the distance value 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 distance value between the seventh lens L7 and the eighth lens L8. In the present embodiment, the third distance value D3 and the fourth distance value D4 are each an adjustable value, that is, a variable. In other words, in the present embodiment, when adjusting the focus of the projection lens unit 14 or adjusting the clarity of the screen, the first lens group 141 and the third lens group 143 are fixed and cannot be moved, but the second lens group 142 is not movable. Is movable between the first lens group 141 and the third lens group 143, thereby adjusting the third distance value D3 and the fourth distance value D4 to achieve the purpose of projecting a clear projection screen.

  As shown in FIG. 2, in the present embodiment, the fourth lens L4 and the fifth lens L5 of the first lens group 141 constitute, for example, a doublet lens, and the eighth lens L8 of the third lens group 143, The ninth lens L9 and the tenth lens L10 constitute, for example, a triplet lens, and the eleventh lens L11 and the twelfth lens L12 of the third lens group 143 constitute a doublet lens, for example. It is not limited to this.

  In the following, an example of each parameter of the projection lens unit 14 is shown. However, the data materials shown in the tables of the following examples do not limit the present invention, and those skilled in the art can refer to the present invention and then change these parameters or settings as appropriate. Belongs to a range.

表１において、表面Ｓ１、Ｓ２は第一レンズＬ１の両表面であり、表面Ｓ３、Ｓ４は第二レンズＬ２の両表面であり、表面Ｓ５、Ｓ６は第三レンズＬ３の両表面であり、第四レンズＬ４と第五レンズＬ５は例えばダブレットレンズを構成し、表面Ｓ８は第四レンズＬ４と第五レンズＬ５の貼り合わせ表面であり、表面Ｓ７は第四レンズＬ４の別の表面であり、表面Ｓ９は第五レンズの別の表面であり、表面Ｓ１０とＳ１１は第六レンズＬ６の両表面であり、表面Ｓ１２とＳ１３は第七レンズＬ７の両表面であり、第八レンズＬ８、第九レンズＬ９および第十レンズＬ１０は例えばトリプレットレンズを構成し、表面Ｓ１５は第八レンズＬ８と第九レンズＬ９の貼り合わせ表面であり、表面Ｓ１６は第九レンズＬ９と第十レンズＬ１０の貼り合わせ表面であり、表面Ｓ１４は第八レンズＬ８の別の表面であり、表面Ｓ１７は第十レンズＬ１０の別の表面であり、第十一レンズＬ１１と第十二レンズＬ１２は例えばダブレットレンズを構成し、表面Ｓ１９は第十一レンズＬ１１と第十二レンズＬ１２の貼り合わせ表面であり、表面Ｓ１８は第十一レンズＬ１１の別の表面であり、表面Ｓ２０は第十二レンズＬ１２の別の表面であり、表面ＳＴＯは開口絞り１４４が存在する平面であり、表面Ｓ２１とＳ２２は第十三レンズの両表面である。本実施例において，光バルブ１２の像形成面（図示せず）は例えば光バルブ端１４ｂに位置する。その他、本実施例において，光バルブ１２と第三レンズ群１４３の第十三レンズＬ１３との間にさらに保護ガラス（ｃｏｖｅｒ ｇｌａｓｓ、図示せず）を設置し、光バルブ１２の像形成面を被覆し、光バルブ１２およびその像形成面を一層保護することができるが、本発明はこれに限定されない。表１において、表面Ｓ２３、Ｓ２４は保護ガラスの両表面であり、なお、表面Ｓ２３は保護ガラスのスクリーン端１４ａに向いている表面であり、表面Ｓ２４は保護ガラスの光バルブ端１４ｂ／光バルブ１２に向いている表面である。表１において、表面Ｓ２５は例えば光バルブ端１４ｂに位置し、つまり、表面Ｓ２５は光バルブ１２の像形成面が存在する平面である。その他、表１の中の間隔は隣接する二つの表面の光軸Ｈ上の直線距離である。例を挙げると、表面Ｓ１の間隔は第一レンズＬ１の表面Ｓ１と表面Ｓ２の光軸Ｈ上における直線距離であり、表面Ｓ２の間隔は第一レンズＬ１の表面Ｓ２と第二レンズＬ２の表面Ｓ３の光軸Ｈ上における直線距離であり、その他の距離も同じ。本実施例において，第五レンズＬ３の屈折率は例えば１．８より大きく（表１が示す第五レンズＬ５の屈折率は１．８８３）、第十三レンズＬ１３の屈折率は例えば１．５２より小さい（表１が示す第十三レンズＬ１３の屈折率は１．４９７）。本実施例において、第五レンズＬ３の屈折率は１．８より大きく、および第十三レンズＬ１３の屈折率が１．５２より小さい場合、映像画面が優れた映像解析度を有し、かつ、映像画面に色収差が発生しない。

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, The fourth lens L4 and the fifth lens L5 constitute, for example, a doublet lens, the surface S8 is a bonded surface of the fourth lens L4 and the fifth lens L5, and the surface S7 is another surface of the fourth lens L4. S9 is another surface of the fifth lens, surfaces S10 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 and the ninth lens. L9 and the tenth lens L10 constitute, for example, a triplet lens, the surface S15 is a bonding surface of the eighth lens L8 and the ninth lens L9, and the surface S16 is a bonding of the ninth lens L9 and the tenth lens L10. The surface S14 is another surface of the eighth lens L8, the surface S17 is another surface of the tenth lens L10, and the eleventh lens L11 and the twelfth lens L12 constitute a doublet lens, for example. The surface S19 is a bonded surface of the eleventh lens L11 and the twelfth lens L12, the surface S18 is another surface of the eleventh lens L11, and the surface S20 is another surface of the twelfth lens L12. The surface STO is a plane on which the aperture stop 144 exists, and the surfaces S21 and S22 are both surfaces of the thirteenth lens. In this embodiment, the image forming surface (not shown) of the light valve 12 is located at the light valve end 14b, for example. In addition, in this embodiment, a protective glass (cover glass, not shown) is further provided between the light valve 12 and the thirteenth lens L13 of the third lens group 143 to cover the image forming surface of the light valve 12. However, the light valve 12 and its image forming surface can be further protected, but the present invention is not limited to this. In Table 1, the surfaces S23 and S24 are both surfaces of the protective glass, the surface S23 is the surface facing the screen end 14a of the protective glass, and the surface S24 is the light valve end 14b of the protective glass / light valve 12 It is the surface which is suitable for. In Table 1, the surface S25 is located at the light valve end 14b, for example, that is, the surface S25 is a plane on which the image forming surface of the light valve 12 exists. In addition, the space | interval in Table 1 is a linear distance on the optical axis H of two adjacent surfaces. For example, the distance between the surface S1 is a linear distance on the optical axis H between the surface S1 and the surface S2 of the first lens L1, and the distance between the surface S2 is the surface between the surface S2 of the first lens L1 and the surface of the second lens L2. This is a linear distance on the optical axis H of S3, and other distances are the same. In this embodiment, the refractive index of the fifth lens L3 is larger than 1.8 (for example, the refractive index of the fifth lens L5 shown in Table 1 is 1.883), and the refractive index of the thirteenth lens L13 is 1.52 for example. It is smaller (the refractive index of the thirteenth lens L13 shown in Table 1 is 1.497). In this example, when the refractive index of the fifth lens L3 is greater than 1.8 and the refractive index of the thirteenth lens L13 is smaller than 1.52, the video screen has an excellent image analysis degree, and No chromatic aberration occurs on the video screen.

  In the present embodiment, the projection lens unit 14 may include two aspheric lenses. For example, in the present embodiment, the first lens L1 and the second lens L2 of the first lens group 141 are, for example, aspheric lenses, and the third lens L3, the fourth lens L4, and the fourth lens L4 of the first lens group 141. The fifth lens L5 is, for example, a spherical lens, the sixth lens L6 and the seventh lens L7 in the second lens group 142 are, for example, spherical lenses, and the eighth lens L8, the ninth lens L9, and the tenth lens in the third lens group 143. The lens L10, the eleventh 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 example satisfy the following aspheric equation (Equation 1).

上記方程式において、Ｚは光軸Ｈ方向のシフト量（ｓａｇ）であり、ｒは光軸Ｈに接近した箇所の曲率半径であり（表１において、表面Ｓ１、Ｓ２、Ｓ３及Ｓ４の曲率半径）、ｋはコーニック定数（ｃｏｎｉｃ ｃｏｎｓｔａｎｔ）であり、ｃは非球面レンズの中心曲率であり、Ａ、Ｂ、Ｃ、Ｄ、Ｅは非球面係数（ａｓｐｈｅｒｉｃ ｃｏｅｆｆｉｃｉｅｎｔ）である。また、本実施例の第一レンズＬ１と第二レンズＬ２の非球面係数は表２が示す通りである。

In the above equation, Z is the shift amount (sag) in the direction of the optical axis H, and r is the radius of curvature at the location close to the optical axis H (in Table 1, the radius of curvature of the surfaces S1, S2, S3 and S4). , K are conic constants, c is the central curvature of the aspherical lens, and A, B, C, D, and E are aspherical coefficients. In addition, Table 2 shows the aspheric coefficients of the first lens L1 and the second lens L2 of this example.

しかし、上記第一レンズ群１４１の第一レンズＬ１と第二レンズＬ２が非球面レンズであることは本発明の一実施例に過ぎず、本発明はこれに限定されない。一実施例において、投影レンズユニット１４は例えば三つの非球面レンズを有し、例を挙げると、第一レンズ群１４１の第一レンズＬ１と第二レンズＬ２および第三レンズ群１４３の第十三レンズＬ１３は非球面レンズである。一実施例において、投影レンズユニット１４は例えば一つの非球面レンズのみを有し、例を挙げると、第一レンズ群１４１の第一レンズＬ１、第二レンズＬ２および第三レンズ群１４３の第十三レンズＬ１３の中の一つが非球面レンズである。

However, the fact that the first lens L1 and the second lens L2 of the first lens group 141 are aspherical lenses is only one example of the present invention, and the present invention is not limited to this. In one embodiment, the projection lens unit 14 includes, 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 of the third lens group 143 are given. The lens L13 is an aspheric lens. In one embodiment, the projection lens unit 14 has, for example, only one aspheric lens, and, for example, the first lens L1, the second lens L2, and the tenth lens group 143 of the first lens group 141. One of the three lenses L13 is an aspheric lens.

  In the above embodiment, the material of the first lens L1 that is an aspheric lens and the second lens L2 that is an aspheric lens is, for example, plastic, and the material of the thirteenth lens L13, which is an aspheric lens, is, for example, glass. In addition, in the present embodiment, the projection ratio (Throw Ray, TR) of the projection lens unit 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 unit 14 reaches 0.79, and the first lens L1 and the second lens L2 In the embodiment in which the thirteenth lens L13 is an aspheric lens, the projection ratio of the projection lens unit 14 reaches 0.5.

  In this embodiment, when the effective focal length of the projection lens unit 14 is f and the effective focal length of the first lens group 141 is f1, the projection lens unit 14 of the present embodiment has 0.8 <| f1 / The relational expression f | <1.9 is satisfied. In this embodiment, when the ratio of the effective focal length f1 of the first lens group 141 and the effective focal length f of the projection lens unit 14 is (ie, | f1 / f |) between 0.8 and 1.9, The image projected by the projection lens unit 14 has an excellent image analysis degree. In this embodiment, when the effective focal length of the projection lens unit 14 is f and the effective focal length of the second lens group 142 is f2, the projection lens unit 14 of the present embodiment has 1.3 <| f2 / f. | <4 is satisfied. 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 unit 14 (ie, | f2 / f |) is between 1.3 and 4, the projection lens The image projected by the unit 14 has an excellent image analysis degree. In this embodiment, when the effective focal length of the projection lens unit 14 is f and the effective focal length of the third lens group 143 is f3, the projection lens unit 14 of this embodiment has 2.7 <| f3 / f. | <6.3, the ratio of the effective focal length f3 of the third lens group 143 to the effective focal length f of the projection lens unit 14 (ie, | f3 / f |) is 2.7 to 6.3. If the interval is between, the image projected by the projection lens unit 14 has an excellent image analysis degree. In the present embodiment, the above relational expression ensures that the position of the light valve 12 is located on the focal point of the third lens group 143, and can improve the problem that the image screen is blurred by the conventional design. In the present embodiment, the effective focal length f of the projection lens unit 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 second lens The effective focal length f2 of the group 142 is, for example, 30.43, and the effective focal length f3 of the third lens group 143 is, for example, 45.75. However, the present invention is not limited to this.

FIG. 3A is a diagram showing a field curvature of a projection lens unit according to an embodiment of the present invention, where T is a tangential image and S is a sagittal image. FIG. 3B is a diagram showing distortion of the projection lens unit according to the embodiment of the present invention. FIG. 3C is a diagram showing lateral color of the lateral method of the projection lens unit according to the embodiment of the present invention. FIG. 3D is a diagram showing longitudinal spherical aberration of the projection lens unit of one embodiment of the present invention, and the ordinate is the pupil radius (radius of the aperture stop). FIG. 3E is a diagram showing a modulation transfer function (MTF) of a projection lens unit according to an embodiment of the present invention. The abscissa is a focus shift, and the ordinate is an optical transfer function (optical). transfer function (OTF). In this embodiment, FIG. 3E shows, for example, spatial frequency 67 line pairs / millimeter (line).
(Pair / mm, lp / mm) may be a diagram obtained by analyzing what is drawn, but the present invention is not limited to this. FIG. 3F is an embodiment of the present invention.
fan), where IMA is the image height. Referring to FIGS. 3A to 3F, in the present embodiment, the drawings shown in FIGS. 3A to 3F are all within the reference range, and therefore the projector 1 of the projection lens unit 14 has excellent image forming quality. Have

  In summary, in the projector of the embodiment of the present invention, the projection lens unit adopts a three-group structure, that is, is arranged in order from the screen end to the light valve end, and the refractive index is negative, positive and positive, respectively. A first lens group, a second lens group, and a third lens group are included. In the projector according to the embodiment of the present invention, the first lens group and the third lens group are fixed without moving when the distance between the projection lens unit and the screen end is changed and the focus is adjusted by the above structural design. Since the objective of focusing can be achieved simply by moving the second lens group, the structure is simple, the manufacturing cost is relatively low, and the need for a short focus design with a projection ratio can be met. In addition, the image projected by the projection lens unit according to the embodiment of the present invention has an excellent image analysis degree.

  What has been described above is a preferred embodiment of the present invention, and the scope of the present invention should not be limited thereto. That is, simple equivalent changes and modifications made based on the claims of the present invention and the detailed description of the invention also belong to the claims of the present invention. In addition, any of the embodiments or claims of the present invention does not necessarily satisfy all of the disclosed objects, advantages, or features of the present invention. In addition, the abstract and the title of the invention are used for searching patent documents, and do not limit the scope of rights of the present invention. Further, terms such as “first”, “second” and the like mentioned in the specification or claims are for distinguishing names or different embodiments or ranges for elements. It does not limit the upper or lower limit of the quantity.

DESCRIPTION OF SYMBOLS 1 Projector 10 Illumination system 12 Optical valve 14 Projection lens unit 14a Screen edge 14b Optical valve end 141 1st lens group 142 2nd lens group 143 3rd lens group 144 Aperture stop H Optical axis D1 1st distance value D2 2nd distance Value D3 Third distance value D4 Fourth distance value IL1 Illumination light beam IL2 Video light beam IL3 Projection light beam L1 First lens L2 Second lens L3 Third lens L4 Fourth lens L5 Fifth lens L6 Sixth lens L7 Seventh lens L8 First Eight lenses L9 Ninth lens L10 Tenth lens L11 Eleventh lens L12 Twelveth lens L13 Thirteenth lens S1-S22 Surface

Claims (26)

A projector,
An illumination system for providing illumination luminous flux;
A light valve disposed on the transmission path of the illumination light beam and for converting the illumination light beam into an image light beam;
A projection lens unit disposed on the transmission path of the image light flux and positioned between the screen end and the light valve end,
The projection lens unit 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 index, and is arranged in order from the screen end to the light valve end, Two lenses, a third lens, a fourth lens, and a fifth lens, and the first lens, the second lens, the third lens, the fourth lens, and the fifth lens have negative and negative refractive indexes, Negative, positive, negative,
The second lens group is disposed between the first lens group and the light valve end, has a positive refractive index, and is arranged in order from the screen end to the light valve end. And a seventh lens, and the refractive indices 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 index, and is arranged in order from the screen end to the light valve end. , The ninth lens, the tenth lens, the eleventh lens, the twelfth lens and the thirteenth lens, and the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the tenth lens. A projector characterized in that the refractive indexes of the second lens and the thirteenth lens are negative, positive, negative, negative, positive and positive, respectively.   The projector according to claim 1, wherein the fourth lens and the fifth lens constitute a doublet lens.   The projector according to claim 1, wherein the eighth lens, the ninth lens, and the tenth lens constitute a triplet lens.   The projector according to claim 1, wherein the eleventh lens and the twelfth lens constitute a doublet lens.   The projector according to claim 1, wherein at least one of the first lens, the second lens, and the thirteenth lens is an aspheric lens. The projection lens unit further includes an aperture stop,
The projector according to claim 1, wherein the aperture stop is disposed between the twelfth lens and the thirteenth lens.   The projector according to claim 1, wherein a refractive index of the fifth lens is greater than 1.8.   The projector according to claim 1, wherein a refractive index of the thirteenth lens is smaller than 1.52.   When the effective focal length of the projection lens unit is f and the effective focal length of the first lens group is f1, 0.8 <| f1 / f | <1.9 is satisfied. Item 2. The projector according to Item 1.   2. When the effective focal length of the projection lens unit is f and the effective focal length of the second lens group is f2, 1.3 <| f2 / f | <4 is satisfied. Projector.   When the effective focal length of the projection lens unit is f and the effective focal length of the third lens group is f3, 2.7 <| f3 / f | <6.3 is satisfied. Item 2. The projector according to Item 1. The second lens group moves between the first lens group and the third lens group;
Having a first distance value between the first lens group and the end of the light valve;
Having a second distance value between the third lens group and the end of the light valve;
The projector according to claim 1, wherein each of the first distance value and the second distance value is a fixed value.   The first lens is a concave / convex 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 double-sided concave lens, The fourth lens is a concave-convex lens with a concave surface facing the screen end, the fifth lens is a convex-concave lens with a concave surface facing the screen end, the sixth lens is a double-sided convex lens, and the seventh lens Is a concave-convex lens with a convex surface facing the screen end, the eighth lens is a convex-concave lens with a convex surface facing the screen end, the ninth lens is a double-sided convex lens, and the tenth lens is a concave surface Is a convex / concave lens facing the screen end, the eleventh lens is a convex / concave lens having a convex surface facing the screen end, and the twelfth lens 'S are two-sided convex lens, and said thirteenth lens is a double-sided lens, projector according to claim 1. A projection lens unit,
The projection lens unit is disposed between the screen end and the light valve end, and 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 index, and is arranged in order from the screen end to the light valve end, Two lenses, a third lens, a fourth lens, and a fifth lens, and the first lens, the second lens, the third lens, the fourth lens, and the fifth lens have negative and negative refractive indexes, Negative, positive, negative,
The second lens group is disposed between the first lens group and the light valve end, has a positive refractive index, and is arranged in order from the screen end to the light valve end. And a seventh lens, and the refractive indices 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 index, and is arranged in order from the screen end to the light valve end. , The ninth lens, the tenth lens, the eleventh lens, the twelfth lens and the thirteenth lens, and the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the tenth lens. A projection lens unit, wherein the second lens and the thirteenth lens have negative, positive, negative, negative, positive, and positive refractive indexes, respectively.   The projection lens unit according to claim 14, wherein the fourth lens and the fifth lens constitute a doublet lens.   The projection lens unit according to claim 14, wherein the eighth lens, the ninth lens, and the tenth lens form a triplet lens.   The projection lens unit according to claim 14, wherein the eleventh lens and the twelfth lens constitute a doublet lens.   The projection lens unit according to claim 14, wherein at least one of the first lens, the second lens, and the thirteenth lens is an aspheric lens.   The projection lens unit according to claim 14, further comprising an aperture stop disposed between the twelfth lens and the thirteenth lens.   The projection lens unit according to claim 14, wherein a refractive index of the fifth lens is larger than 1.8.   The projection lens unit according to claim 14, wherein a refractive index of the thirteenth lens is smaller than 1.52.   When the effective focal length of the projection lens unit is f and the effective focal length of the first lens group is f1, 0.8 <| f1 / f | <1.9 is satisfied. Item 15. The projection lens unit according to Item 14.   15. The relationship of 1.3 <| f2 / f | <4 is satisfied when the effective focal length of the projection lens unit is f and the effective focal length of the second lens group is f2. The projection lens unit described in 1.   The relation 2.7 <| f3 / f | <6.3 is satisfied when the effective focal length of the projection lens unit is f and the effective focal length f3 of the third lens group. 14. A projection lens unit according to 14.   The second lens group moves between the first lens group and the third lens group, and has a first distance value between the first lens group and the light valve end, and the third lens 15. Projection according to claim 14, characterized in that it has a second distance value between a group and the end of the light valve, and the first distance value and the second distance value are each fixed values. Lens unit.   The first lens is a concave / convex 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 double-sided concave lens, The fourth lens is a concave-convex lens with a concave surface facing the screen end, the fifth lens is a convex-concave lens with a concave surface facing the screen end, the sixth lens is a double-sided convex lens, and the seventh lens Is a concave-convex lens with a convex surface facing the screen end, the eighth lens is a convex-concave lens with a convex surface facing the screen end, the ninth lens is a double-sided convex lens, and the tenth lens is a concave surface Is a convex / concave lens facing the screen end, the eleventh lens is a convex / concave lens having a convex surface facing the screen end, and the twelfth lens 'S are two-sided convex lens, the thirteenth lens is characterized by a double-sided convex projection lens unit according to claim 14.

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