JP2006220809A - Projection lens and projector using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection lens that has a large angle between a screen and a panel and exhibits satisfactory optical performance even when zooming takes place from the wide end to the telephoto end. <P>SOLUTION: The projection leans has a variable power function of projecting onto a screen an image of an image element being to be projected. The image element is disposed at an angle to the screen. The optical axes of lens groups moved to vary a power are disposed on the same straight line. Lens groups that are not moved when a power is varied are composed of lenses deviating from the optical axis. The projection lens includes at least one free curved face lens at least one face of which is an aspheric face that does have an axis of rotational symmetry. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projection lens and an image projection apparatus using the same, and in particular, in a reflection type liquid crystal projector that illuminates a panel from an oblique direction, an image of a projected image element tilted with respect to the screen is displayed without distortion. It is suitable when projecting onto the screen.

  In recent years, the price of enlarging projection apparatuses such as liquid crystal projectors has been reduced, and it has become possible to easily enjoy bright images on a large screen even at home.

  Many of these projectors use a transmissive liquid crystal panel as an image display means. However, the transmissive liquid crystal panel has a defect that the image is rough and the image quality is slightly poor because the pixel opening is small. In contrast to the current situation, by using a reflective liquid crystal panel with a large pixel aperture, it is possible to obtain a brighter image with higher definition than a transmissive liquid crystal panel. Currently, many optical systems using a polarizing beam splitter have been proposed as an optical system using a reflective liquid crystal panel. However, the polarizing beam splitter has a contrast variation due to variations in characteristics depending on the angle of light incident on the polarizing beam splitter. This causes a decrease and the cost also increases.

  On the other hand, there is a configuration as shown in FIG. 14 as an example of an optical system that does not use a polarizing beam splitter. In this example, light emitted from the light source 59 is guided to the panel 62 side by reflection at the mirrors 60 and 61, the panel 62 is illuminated from an oblique direction, and the light illuminating the panel 62 is incident on the projection lens 63 as image light. Then, the image is enlarged and projected on the screen 64. In this example, since the panel 62 is illuminated from an oblique direction and enlarged and projected, the panel 62 and the screen 64 are inclined, and a coaxial projection lens in which the optical axes of all the lenses of the projection lens are located on the same straight line is used. If it is used, the distortion of the projected image on the screen will increase, and even if an aspherical lens is used, its correction is quite difficult. Therefore, in order to project an image formed by a panel inclined with respect to the screen onto the screen without distortion, it is necessary to decenter a part of the projection lens.

  In such a situation, there is a configuration as shown in FIG. 15 as an example in which a part of the projection lens is decentered (Patent Document 1). This projection lens has a moving lens group 66 that moves in a direction different from the optical axis direction between the diaphragm 70 of the projection lens and the panel 71 and continuously corrects trapezoidal distortion caused by oblique projection, Two free-form surface lenses 68 and 69 are provided in a lens group 65 located on the opposite side of the panel 71 when viewed from the moving lens group 66. When zooming is performed in this example, the moving lens group 66 and the lens group 65 are shifted. However, the lens group 65 includes a free-form surface lens and the lens group 66 is in a direction different from the optical axis direction. It is configured to shift.

Japanese Patent Laid-Open No. 2001-141994

  However, in the configuration of the above-mentioned Patent Document 1, it is considerably difficult in design to maintain the optical performance at a level that does not cause a practical problem at all zoom positions from the wide end to the tele end.

  An object of the present invention is to realize a projection lens having a large angle formed by a screen and a panel and having good optical performance even when zooming from the wide end to the tele end.

  In order to achieve the above object, the invention according to claim 1 is a projection lens having a zooming function for projecting an image of a projection image element onto a screen, and the projection image element is inclined with respect to the screen. The optical axis of the lens group that moves during zooming is on the same straight line, and the lens group that does not move during zooming consists of a lens that is decentered from the optical axis, and at least one surface has an aspherical shape that does not have a rotationally symmetric axis. It has at least one free-form surface lens.

  In addition, the present invention provides a projection lens having a magnification function for projecting an image of a projection image element onto a screen, and the projection image element is arranged to be inclined with respect to the screen, and the light of the lens group that moves at the magnification. A lens group whose axes are collinear and does not move in zooming is composed of lenses decentered from the optical axis, and at least one surface is a free-form surface lens formed in an aspherical shape having no rotational symmetry axis, and at least Each surface has at least one aspherical lens formed in an aspherical shape having a rotationally symmetric axis.

A magnifying projection device that magnifies and projects an image formed by a reflective liquid crystal panel as a projection image element onto a screen, and is arranged so as to be shifted with respect to the optical axis of the projection lens and further tilted with respect to the screen. In the magnifying projection apparatus including an image element, the projection lens includes a first convex lens having a positive refractive power, a second concave lens having a negative refractive power, and a third concave lens having a negative refractive power from the screen side. A fourth concave lens having a negative refractive power, a fifth convex lens having a positive refractive power, a sixth convex lens having a positive refractive power, a seventh concave lens having a negative refractive power, and a positive refractive power. An eighth convex lens, a ninth concave lens having a negative refractive power, a tenth convex lens having a positive refractive power, an eleventh concave lens having a negative refractive power, a twelfth convex lens having a positive refractive power, A thirteenth concave lens having a refractive power, a fourteenth convex lens having a positive refractive power, a fifteenth convex lens having a positive refractive power, and a sixteenth convex lens having a positive refractive power. One group is composed of the first to third lenses, the second group is composed of the fourth to sixth lenses, the third group is composed of the seventh and eighth lenses, and the fourth group Are composed of the ninth to sixteenth lenses, and the seventh and eighth lenses included in the third group are a surface on the projected image element side of the seventh lens and a screen side of the eighth lens. The eleventh lens and the twelfth lens included in the fourth group are bonded on the projection image element side surface of the eleventh lens and the screen side surface of the twelfth lens. The thirteenth and fourteenth lenses are projected images of the thirteenth lens. The element side surface and the screen side surface of the fourteenth lens are bonded together, the optical axes of the first, second and third groups are on the same straight line, and the fourth group is a lens constituting the fourth group The tenth to sixteenth lenses are decentered from the common optical axis of the first, second, and third groups, and both surfaces of the tenth lens included in the fourth group do not have rotational symmetry axes. An aspherical shape is used, and both surfaces of the sixteenth lens are aspherical without an axis of rotational symmetry, and a common optical axis of the first to third groups and a normal line of the projected image element. When the angle formed is θ,
−12 ° <θ <12 ° (1)
By satisfying the above, it is possible to reduce the occurrence of decentration coma aberration, decentration distortion, and lateral chromatic aberration, so that a high-resolution projection lens can be realized, and because the number of lenses can be reduced, the projection lens can be miniaturized.

As another configuration, the projection lens includes a first convex lens having a positive refractive power, a second concave lens having a negative refractive power, and a third concave lens having a negative refractive power from the screen side. A fourth concave lens having a negative refractive power, a fifth convex lens having a positive refractive power, a sixth convex lens having a positive refractive power, a seventh concave lens having a negative refractive power, and a positive refractive power. An eighth convex lens having a positive refractive power; a tenth concave lens having a negative refractive power; an eleventh convex lens having a positive refractive power; a twelfth concave lens having a negative refractive power; A thirteenth convex lens having a positive refractive power, a fourteenth concave lens having a negative refractive power, a fifteenth convex lens having a positive refractive power, a sixteenth convex lens having a positive refractive power, and a positive refractive power Composed of a 17th convex lens, The first lens group is composed of the first to third lenses, the second lens group is composed of the fourth to sixth lenses, and the third lens group is composed of the seventh and eighth lenses. The fourth group is composed of the ninth to seventeenth lenses, and the seventh and eighth lenses included in the third group include the surface of the seventh lens on the projected image element side and the eighth lens. The twelfth and thirteenth lenses included in the fourth group are bonded to each other on the screen side surface of the twelfth lens and the screen side surface of the thirteenth lens. The fourteenth and fifteenth lenses are bonded to each other at the projected image element side surface of the fourteenth lens and the screen side surface of the fifteenth lens. The optical axes are on the same straight line, and the fourth group includes the lenses constituting the fourth group. Lenses 10 to 17 are decentered from the common optical axes of the first to third groups, and the surface of the eleventh lens included in the fourth group on the projected image element side has a rotational symmetry axis. The surface of the sixteenth lens on the screen side has an aspherical shape having no rotational symmetry axis, and the surface of the seventeenth lens on the projection image element side has a rotational symmetry axis. When it is an aspherical shape and the angle between the common optical axis of the first to third groups and the normal line of the projected image element is θ,
−12 ° <θ <12 ° (1)
By satisfying the above, it is possible to reduce the occurrence of decentration coma aberration, decentration distortion, and lateral chromatic aberration, so that a high-resolution projection lens can be realized, and because the number of lenses can be reduced, the projection lens can be miniaturized.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
FIG. 1 is a diagram for explaining the configuration of the first embodiment of the present invention.

  In FIG. 1, 1 is a convex lens having a positive refractive power, 2 is a concave lens having a negative refractive power, 3 is a concave lens having a negative refractive power, 4 is a concave lens having a negative refractive power, and 5 is a positive lens. A convex lens having a refractive power, 6 is a convex lens having a positive refractive power, 7 is a concave lens having a negative refractive power, 8 is a convex lens having a positive refractive power, and 9 is a concave lens having a negative refractive power.

  Further, 10 is a convex lens having a positive refractive power, 11 is a concave lens having a negative refractive power, 12 is a convex lens having a positive refractive power, 13 is a concave lens having a negative refractive power, and 14 has a positive refractive power. A convex lens, 15 is a convex lens having a positive refractive power, and 16 is a convex lens having a positive refractive power. Reference numeral 17 denotes a prism as a back focus, 18 denotes a screen, and 19 denotes a reflective liquid crystal panel (projected image element) inclined with respect to the screen 18.

  Further, 20 is a surface on the screen 18 side of the concave lens 9 provided with a diaphragm, 21 is an aspherical surface having no rotational symmetry axis on the screen 18 side of the convex lens 10, and 22 is a rotational symmetry axis on the panel 19 side of the convex lens 10. , 23 is an aspheric surface having no rotational symmetry axis on the screen 18 side of the convex lens 16, and 24 is an aspheric surface having no rotational symmetry axis on the panel 19 side of the convex lens 16. Reference numeral 25 denotes a first group of projection lenses, which includes three lenses: a convex lens 1, a concave lens 2, and a concave lens 3. Reference numeral 26 denotes a second group of projection lenses, which includes three lenses, a concave lens 4, a convex lens 5, and a convex lens 6. Reference numeral 27 denotes a third group of projection lenses, in which a concave lens 7 and a convex lens 8 are bonded to each other on the surface of the panel 7 and the surface of the screen 8.

  Reference numeral 28 denotes a fourth group of projection lenses, which includes a concave lens 9, a convex lens 10, a concave lens 11, a convex lens 12, a concave lens 13, a convex lens 14, a convex lens 15, and a convex lens 16, and the concave lens 11 and the convex lens 12 are arranged on the panel side of 11. The concave lens 13 and the convex lens 14 are bonded to each other at the 13 panel side surface and the 14 screen side surface.

  In the lens groups from the first group 25 to the third group 27, the optical axes are on the same straight line 29, and in the fourth group 28, each lens constituting 28 is a common light of the first, second and third groups. When the angle between the common optical axis 29 from the first group 25 to the third group 27 and the normal line of the projection image element 19 is θ, the expression (1) is obtained. The projected image element 19 is positioned so as to satisfy.

  Here, when the projected image element 19 is largely inclined with respect to the screen 18 and θ exceeds the range of the expression (1), the decentering amount of the fourth group lens for correcting the decentration distortion and the decentration coma aberration is large. The decentration aberrations tend to get worse and become too large, and a sufficient resolving power cannot be obtained. For this reason, it is desirable that the angle θ formed by the common optical axis 29 from the first group 25 to the third group 27 and the normal line of the projection image element 19 satisfies the condition of the expression (1).

  FIG. 2 is an optical path diagram in the present embodiment.

  As shown in FIG. 2, the image light formed by the panel 19 that is shifted from the common optical axis of the first to third groups of the projection lens in the vertical direction and tilted with respect to the screen has a positive refractive power. Refracted by the fourth group 28 having a refractive index, incident on the third group 27 and refracted by the third group 27 having a negative refractive power, and incident on the second group 26 and refracted by the second group 26 having a positive refractive power. Then, after entering the first group 25, the light is refracted by the first group 25 having negative refractive power, exits from the first group 25, and then reaches the screen.

  FIG. 3 is an eccentric distortion diagram in which the original image of the panel is enlarged and projected and the distortion of the projection image is calculated on the screen when the projection lens is at the wide end. The distortion is symmetrical in the horizontal direction and asymmetric in the vertical direction. It has become.

  FIG. 4 is an eccentric distortion diagram in which the original image of the panel is enlarged and projected on the screen when the projection lens is at the telephoto end, and the distortion of the projection image is calculated on the screen. The distortion is symmetric in the horizontal direction and asymmetric in the vertical direction. It has become.

  FIG. 5 is a spot diagram of C-line, d-line and F-line on the panel when reverse tracing is performed from the screen side when the projection lens is at the wide end.

  FIG. 6 is a spot diagram of C-line, d-line and F-line on the panel when reverse tracing is performed from the screen side when the projection lens is at the telephoto end.

<Embodiment 2>
FIG. 7 is a diagram for explaining the configuration of the second embodiment of the present invention.

  As shown in FIG. 2, 30 is a convex lens having a positive refractive power, 31 is a concave lens having a negative refractive power, 32 is a concave lens having a negative refractive power, 33 is a concave lens having a negative refractive power, and 34 is a positive lens. Is a convex lens having a positive refractive power, 35 is a concave lens having a negative refractive power, 37 is a convex lens having a positive refractive power, 38 is a convex lens having a positive refractive power, and 39 is a negative lens. 40 is a convex lens having a positive refractive power, 41 is a concave lens having a negative refractive power, 42 is a convex lens having a positive refractive power, 43 is a concave lens having a negative refractive power, and 44 is a positive lens. A convex lens 45 having a refractive power of 45, a convex lens 45 having a positive refractive power, and a convex lens 46 having a positive refractive power.

  47 is a prism as a back focus, 48 is a screen, and 49 is a reflective liquid crystal panel (projected image element) inclined with respect to the screen 48.

  50 is a surface of the convex lens 38 on the panel 49 side where a diaphragm is provided, 51 is an aspherical surface having a rotational symmetry axis on the panel 49 side of the convex lens 40, 52 is not having a rotational symmetry axis on the screen 48 side of the convex lens 45 An aspheric surface 53 is an aspheric surface having a rotational symmetry axis on the panel 49 side of the convex lens 46.

  Reference numeral 54 denotes a first group of projection lenses, which includes three lenses, a convex lens 30, a concave lens 31, and a concave lens 32.

  Reference numeral 55 denotes a second group of projection lenses, which includes three lenses, a concave lens 33, a convex lens 34, and a convex lens 35.

  Reference numeral 56 denotes a third lens group in which a concave lens 36 and a convex lens 37 are bonded to each other on the panel side surface 36 and the screen side surface 37.

  Reference numeral 57 denotes a fourth group of projection lenses, which includes a convex lens 38, a concave lens 39, a convex lens 40, a concave lens 41, a convex lens 42, a concave lens 43, a convex lens 44, a convex lens 45, and a convex lens 46. The concave lens 41 and the convex lens 42 are 41 panels. The concave lens 43 and the convex lens 44 are bonded to each other at the panel-side surface 43 and the screen-side surface 44.

  The lens groups from the first group 54 to the third group 56 have optical axes on the same straight line 58, and the fourth group 57 has the lenses constituting the lens 57 deviated from the common optical axis 58 of the first to third groups. When the angle between the common optical axis 58 from the first group 54 to the third group 56 and the normal line of the projection image element 49 is θ, the expression (1) is satisfied. The projected image element 49 is located.

  Here, when the projected image element 49 is largely inclined with respect to the screen 48 and θ exceeds the range of the expression (1), the decentering amount of the fourth lens group for correcting the decentration distortion and the decentration coma aberration is large. The decentration aberrations tend to get worse and become too large, and a sufficient resolving power cannot be obtained. For this reason, it is desirable that the angle θ formed by the common optical axis 58 from the first group 54 to the third group 56 and the normal line of the projection image element 49 satisfies the condition of the expression (1).

  FIG. 8 is an optical path diagram in the present embodiment.

  As shown in FIG. 8, the image light formed by the panel 49 that is shifted from the common optical axis of the first, second, and third groups of the projection lens in the vertical direction and tilted with respect to the screen is positive. Refracted by the fourth group having a refractive power of ## EQU2 ## refracted by the third group having a negative refractive power incident on the third group, refracted by the second group having a positive refractive power incident on the second group, After entering the first group, the light is refracted by the first group having a negative refractive power, exits from the first group, and then reaches the screen.

  FIG. 9 is an eccentric distortion diagram obtained by enlarging and projecting the original image of the panel when the projection lens is at the wide end and calculating the distortion of the projection image on the screen. The distortion is symmetric in the horizontal direction and asymmetric in the vertical direction. It has become.

  FIG. 10 is an eccentric distortion diagram obtained by enlarging and projecting the original image of the panel when the projection lens is at the telephoto end and calculating the distortion of the projection image on the screen. The distortion is symmetric in the horizontal direction and asymmetric in the vertical direction. It has become.

  FIG. 11 is a spot diagram of C-line, d-line and F-line on the panel when reverse tracing is performed from the screen side when the projection lens is at the wide end.

  FIG. 12 is a spot diagram of C-line, d-line and F-line on the panel when reverse tracing is performed from the screen side when the projection lens is at the telephoto end.

  Next, numerical examples will be shown.

  Tables 1 and 2 are first and second numerical examples of the present invention, respectively.

  The aspherical shape having no rotational symmetry axis shown in Tables 1 and 2 has a shape having an aspherical surface by a Zernike polynomial in a shape function representing a quadratic curved surface, and is represented by a function shown in the following equation.

ここに、ｒは各面の基本曲率半径であり、ｃはｃ＝１／ｒである。又、ｃｉは各面におけるｉ番目のゼルニケ多項式の非球面係数である。

Here, r is the basic radius of curvature of each surface, and c is c = 1 / r. Further, ci is an aspheric coefficient of the i-th Zernike polynomial on each surface.

  The aspherical shape having a rotationally symmetric axis shown in Table 2 has an incident height of an incident ray from the surface vertex of the surface on which the aspherical surface is set to a direction perpendicular to the optical axis of the surface, r, and the surface vertex curvature radius. The reciprocal is c, the conic constant is K, the fourth-order aspheric coefficient is A, the sixth-order aspheric coefficient is B, the eighth-order aspheric coefficient is C, the tenth-order aspheric coefficient is D, and the twelfth-order aspheric surface. When the coefficient is E, the 14th aspheric coefficient is F, the 16th aspheric coefficient is G, the 18th aspheric coefficient is H, and the 20th aspheric coefficient is J,

で表される非球面形状である。

It is an aspherical shape represented by

<Table 1>
Screen center position X0 = 0, Y0 =
0, Z0 = 0
Screen side area size Xmin = 0,
Xmax = 710
Ymin = −532, Ymax = 532
1 r: 184.683 d: 4.378 n: 1.806 v: 40.9
2 r: -138.249 d: 0.500 n: v:
3 r: 96.383 d: 1.423 n: 1.516 v: 64.1
4 r: 32.809 d: 7.987 n: v:
5 r: -45.647 d: 1.339 n: 1.516 v: 64.1
6 r: -132.454 d: 14.054 n: v:
7 r: -338.735 d: 3.360 n: 1.699 v: 30.1
8 r: 33.443 d: 1.299 n: v:
9 r: 36.452 d: 7.000 n: 1.835 v: 42.7
10 r: -136.512 d: 1.060 n: v:
11 r: 108.880 d: 2.948 n: 1.786 v: 44.2
12 r: -1330.552 d: 7.061 n: v:
13 r: -45.752 d: 0.950 n: 1.603 v: 60.6
14 r: 17.175 d: 5.707 n: 1.805 v: 25.4
15 r: 127.941 d: 3.727 n: v:
16 r: -67.830 d: 0.950 n: 1.699 v: 30.1
17 r: 138.284 d: 1.652 n: v:
18 dY: -0.183 tilt: 3.408
r: -70.326 d: 4.001 n: 1.525 v: 56.2
c4: 1.185e-04 c5: -3.000e-06 c9: 9.734e-06 C10: 2.929e-06
c11: 3.864e-07 c12: -6.548e-08 c13:
-9.127e-07 c19: 4.485e-09
c20: -3.708e-09 c21: 7.634e-09 c22:
-1.127e-10 c23: 3.695e-10
c24: 8.731e-11 c25: 5.230e-10
19 dY: 1.988 tilt: 3.408
r: -18.065 d: 0.500 n: v:
c4: 8.223e-05 c5: -6.197e-05 c9: 4.714e-06 C10: -4.728e-06
c11: 4.960e-07 c12: -3.302e-07 c13:
-1.106e-07 c19: 2.279e-08
c20: -5.594e-09 c21: 1.261e-08 c22:
-6.416e-11 c23: 3.507e-10
c24: -7.001e-11 c25: 1.058e-09
20 dY: 1.913 tilt: 2.468
r: -19.150 d: 0.950 n: 1.648 v: 33.8
21 dY: 1.954 tilt: 2.468
r: 131.627 d: 4.039 n: 1.804 v: 46.6
22 dY: 2.128 tilt: 2.468
r: -32.918 d: 1.815 n: v:
23 dY: 1.885 tilt: 3.610
r: -19.120 d: 0.950 n: 1.689 v: 31.1
24 dY: 1.945 tilt: 3.610
r: 52.205 d: 7.425 n: 1.487 v: 70.2
25 dY: 2.413 tilt: 3.610
r: -27.964 d: 0.500 n: v:
26 dY: 4.031 tilt: 6.788
r: 419.451 d: 7.384 n: 1.720 v: 50.2
27 dY: 4.904 tilt: 6.788
r: -35.881 d: 0.752 n: v:
28 dY: -6.747 tilt: 9.117
r: 37.334 d: 7.252 n: 1.525 v: 56.2
c4: 2.009e-04 c5: -3.989e-05 c9: -1.069e-06 C10: -3.091e-06
c11: -2.905e-08 c12: 2.742e-08 c13:
-1.656e-08 c19: -1.569e-11
c20: 3.783e-10 c21: 1.647e-09 c22: -3.266e-11 c23: -2.009e-11
c24: -3.636e-12 c25: -1.055e-11
29 dY: 1.007 tilt: 9.117
r: d: 2.245 n: v:
c4: 1.358e-04 c5: 4.870e-05 c9: -1.276e-05 C10: -2.710e-06
c11: -1.965e-08 c12: 3.962e-08 c13: 2.251e-07 c19: 4.596e-10
c20: 1.505e-09 c21: 2.414e-09 c22: -9.425e-12 c23: -1.035e-11
c24: -5.417e-11 c25: -1.869e-11
30 dY: -5.738 tilt: 11.000
30 r: d: 26.000 n: 1.516 v: 64.1
31 dY: 0.000 tilt: 0.000
31 r: d: 23.300 n: 1.805 v: 25.4
32 dY: 0.000 tilt: 0.000
r: d: 7.043 n: v:
33 dY: 0.000 tilt: 0.000
r: d: 0.002 n: v:
Zoom variable interval
WT
d 6 14.054 0.500
d12 7.061 15.756
d15 3.727 2.729
Here, 1 to 33 indicate lens surface numbers, 1 to 6 are the first group, 7 to 12 are the second group, 13 to 15 are the third group, 16 to 29 are the fourth group, and 30 to 30. 32 is a prism as a back focus, and 33 is an image plane. Further, dY and tilt respectively indicate the amount of eccentricity in the lens of the fourth group, and as shown in FIG. 13, dY is the amount of parallel eccentricity perpendicular to the common optical axis from the first group to the third group, tilt is an inclination angle (°) with the surface vertex of each coaxial lens group as the rotation center.

Numerical value of formula (1) θ = 11 ° (> −12 °, <12 °)
<Table 2>
Screen center position X0 = 0, Y0 =
0, Z0 = 0
Screen side area size Xmin = 0,
Xmax = 710
Ymin = −532, Ymax = 532
1 r: 94.785 d: 4.614 n: 1.806 v: 40.9
2 r: -1055.437 d: 2.293 n: v:
3 r: 46.258 d: 0.950 n: 1.516 v: 64.1
4 r: 29.770 d: 5.813 n: v:
5 r: 73.648 d: 0.950 n: 1.516 v: 64.1
6 r: 33.355 d: 12.443 n: v:
7 r: -59.028 d: 0.950 n: 1.699 v: 30.1
8 r: 52.714 d: 0.732 n: v:
9 r: 52.660 d: 5.227 n: 1.835 v: 42.7
10 r: -94.129 d: 0.500 n: v:
11 r: 56.421 d: 3.407 n: 1.786 v: 44.2
12 r: 1063.856 d: 2.050 n: v:
13 r: -46.274 d: 0.950 n: 1.603 v: 60.6
14 r: 18.417 d: 9.517 n: 1.805 v: 25.4
15 r: 35.963 d: 12.326 n: v:
16 r: -132.759 d: 1.820 n: 1.516 v: 64.1
17 r: -109.160 d: 0.500 n: v:
18 r: d: 0.741 n: v:
19 r: d: -0.741 n: v:
20 dY: 1.490 tilt: -1.865
r: -590.190 d: 0.950 n: 1.699 v: 30.1
21 dY: 1.459 tilt: -1.865
r: 70.027 d: 0.838 n: v:
22 dY: 3.622 tilt: 3.298
r: 59.072 d: 4.335 n: 1.697 v: 55.5
23 dY: 3.871 tilt: 3.298
r: -58.659 d: 0.500 n: v:
K: -1.00062 A: 5.319e-07 B: 2.022e-09 C: -3.510e-12
D: -6.445e-15 E: 0.000e + 00 F: 0.000e + 00 G: 0.000e + 00
H: 0.000e + 00 J: 0.000e + 00
24 dY: -0.316 tilt: 9.696
r: 31.651 d: 0.950 n: 1.648 v: 33.8
25 dY: -0.156 tilt: 9.696
r: 16.397 d: 2.845 n: 1.804 v: 46.6
26 dY: 0.323 tilt: 9.696
r: 23.537 d: 4.933 n: v:
27 dY: 1.251 tilt: 11.757
r: -16.846 d: 1.721 n: 1.699 v: 30.1
28 dY: 1.602 tilt: 11.757
r: 106.033 d: 7.034 n: 1.487 v: 70.2
29 dY: 3.035 tilt: 11.757
r: -18.955 d: 0.500 n: v:
30 dY: 0.537 tilt: 8.602
r: 117.653 d: 5.215 n: 1.571 v: 33.8
c4: 5.325e-05 c5: -8.638e-06 c9: -2.311e-07 C10: 2.843e-08
c11: 2.410e-09 c12: 1.116e-08 c13: -6.954e-10 c19: 0.000e + 00
c20: 0.000e + 00 c21: 0.000e + 00 c22: 0.000e + 00 c23: 0.000e + 00
c24: 0.000e + 00 c25: 0.000e + 00
31 dY: 0.676 tilt: 8.602
r: -47.648 d: 0.500 n: v:
32 dY: -0.924 tilt: 5.131
r: 48.036 d: 5.860 n: 1.603 v: 60.6
33 dY: -0.400 tilt: 5.131
r: -144.095 d: 0.778 n: v:
K: -1.08916 A: 3.657e-08 B: -1.137e-10 C: -5.009e-13
D: 8.907e-16 E: 0.000e + 00 F: 0.000e + 00 G: 0.000e + 00
H: 0.000e + 00 J: 0.000e + 00
34 dY: -2.486 tilt: 8.000
34 r: d: 26.000 n: 1.516 v: 64.1
35 dY: 0.000 tilt: 0.000
35 r: d: 23.300 n: 1.805 v: 25.4
36 dY: 0.000 tilt: 0.000
r: d: 7.286 n: v:
37 dY: 0.000 tilt: 0.000
r: d: -0.286 n: v:
Zoom variable interval
WT
d6 12.443 9.395
d12 2.050 7.167
d15 12.326 8.990
Here, 1 to 37 indicate lens surface numbers, 1 to 6 are the first group, 7 to 12 are the second group, 13 to 15 are the third group, 16 to 33 are the fourth group, and 34 to 34. 36 is a prism as a back focus, and 37 is an image plane. Further, dY and tilt respectively indicate the amount of eccentricity in the wide converter lens. As shown in FIG. 13, dY is the amount of parallel eccentricity perpendicular to the common optical axis from the first group to the third group, and tilt is The tilt angle (°) with the surface vertex of each coaxial lens group as the center of rotation.

Numerical value of formula (1) θ = 8 ° (> −12 °, <12 °)

It is a block diagram of Embodiment 1 of this invention. FIG. 3 is an optical path diagram of the projection optical system in Embodiment 1 of the present invention. It is a distortion figure of the projection image in the wide end of Embodiment 1 of this invention. It is a distortion figure of the projection image in the tele end of Embodiment 1 of this invention. It is a spot diagram in the wide end of Embodiment 1 of this invention. It is a spot diagram in the tele end of Embodiment 1 of this invention. It is a block diagram of Embodiment 2 of this invention. It is an optical path figure of the projection optical system in Embodiment 2 of this invention. It is a distortion figure of the projection image in the wide end of Embodiment 2 of this invention. It is a distortion figure of the projection image in the tele end of Embodiment 2 of this invention. It is a spot diagram in the wide end of Embodiment 2 of this invention. It is a spot diagram in the tele end of Embodiment 2 of this invention. It is a figure explaining the structure of this invention. It is explanatory drawing of a prior art example. It is explanatory drawing of a prior art example.

Explanation of symbols

18 Screen 19 Liquid crystal panel (Projected image element)
25 1st group 26 2nd group 27 3rd group 28 4th group

Claims (6)

A projection lens having a zooming function for projecting an image of a projection image element onto a screen,
The image element to be projected is arranged to be inclined with respect to the screen, and the optical axis of the lens group that moves in zooming is collinear, and the lens group that does not move in zooming consists of a lens decentered from the optical axis, and at least A projection lens comprising at least one free-form surface lens having one surface formed in an aspherical shape having no rotational symmetry axis.   2. The projection lens according to claim 1, wherein one of the free-form surface lenses is located closest to the projection image element among the lenses of the lens group that does not move during zooming. A projection lens having a zooming function for projecting an image of a projection image element onto a screen,
The image element to be projected is arranged to be inclined with respect to the screen, and the optical axis of the lens group that moves in zooming is collinear, and the lens group that does not move in zooming consists of a lens decentered from the optical axis, and at least It has at least one free-form surface lens formed with an aspherical shape with one surface having no rotational symmetry axis and at least one aspherical lens formed with an aspherical shape with at least one surface having a rotational symmetry axis. Projection lens.   4. The projection lens according to claim 3, wherein one of the free-form surface lens and the aspherical lens is positioned closest to the projection image element among the lenses of the lens group that does not move during zooming. When the angle formed by the optical axis of the lens group that moves in zooming of the projection lens and the normal line of the projection image element is θ,
-12 ° <θ <12 °
The projection lens according to any one of claims 1 to 4, wherein:   A projection apparatus comprising: the projection lens according to claim 1; and an image projection element.

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