JP2011033738A - Projection optical system and projection type display using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection optical system that has compactness suitable for mounting on a front projection type projector, has good assemblability, and can correct various aberrations, and a projection display device using the same. obtain.
An image on an image display surface is enlarged and projected onto a screen by a first optical system comprising a plurality of lenses and a second optical system comprising a reflecting mirror having a concave aspherical shape. To do. All optical surfaces constituting the first optical system 1 and the second optical system 2 is composed of a rotationally symmetric surface, twelfth lens L ₁₂ and the second reflecting mirror 4 of the optical system 2 of the first optical system, the optical axis The other lenses of the first optical system 1 are arranged coaxially with each other on the optical axis Z.
[Selection] Figure 1

Description

  The present invention relates to a projection optical system and a projection display device, and more particularly to an image displayed on an image display element on a screen using a first optical system composed of a plurality of lenses and a second optical system composed of a concave mirror. The present invention relates to a projection optical system for forming an image and a projection display device using the same.

  In general, a projection optical system used in a projector is required to have a long back focus and an entrance pupil as viewed from the reduction side (light valve side) sufficiently far away, that is, the reduction side must have telecentricity. Is done.

  In addition, with the recent improvement in performance of the light valve, good aberration correction corresponding to the resolution of the light valve is also required. Furthermore, in consideration of use in a relatively bright and narrow indoor space such as for presentations, a brighter and wider-angle projection optical system has been strongly demanded.

  2. Description of the Related Art Conventionally, there has been known a projection optical system in which a refractive first optical system composed of a plurality of lenses and a reflective second optical system composed of a concave mirror are combined (see Patent Documents 1 to 3 below). Since this type of projection optical system is a relay system between the refractive first optical system and the reflective second optical system, the focal length can be shortened and it is suitable for widening the angle. .

JP 2004-258620 A JP 2006-235516 A JP 2007-79524 A

  However, the one described in Patent Document 1 employs a complicated decentered optical system in which a plurality of optical surfaces are shifted or tilted with respect to the optical axis, and is difficult to assemble.

  On the other hand, those described in Patent Documents 2 and 3 are easy to assemble because they employ a coaxial optical system, but are mainly configured to be mounted on a rear projection type projector. For this reason, there is a problem that the size of the entire system is large in order to mount on a front projection type.

  In order to obtain a compact projection optical system suitable for mounting on a front projection type projector, it is necessary to shorten the overall length of the optical system and the size of the concave mirror. In this case, since various aberrations such as distortion are expected to deteriorate, it is important to take countermeasures.

  The present invention has been made in view of such circumstances, and has a compactness suitable for mounting on a front projection type projector, has good assemblability, and can correct various aberrations satisfactorily. It is an object of the present invention to provide a system and a projection display device using the same.

A first projection optical system according to the present invention is a projection optical system for enlarging and projecting an original image on a reduction-side conjugate plane onto an enlargement-side conjugate plane,
In order from the reduction side, a first optical system that forms an intermediate image conjugate with the original image, and a second optical system that forms a final image conjugate with the intermediate image on the enlargement-side conjugate surface, Arranged,
The first optical system comprises a plurality of lenses, and the second optical system comprises a reflecting mirror having a concave aspheric shape,
All the optical surfaces constituting the first optical system and the second optical system are constituted by rotationally symmetric surfaces,
One lens of the plurality of lenses of the first optical system and the reflection mirror of the second optical system are arranged decentered with respect to the optical axis,
Other lenses other than the one lens of the first optical system are arranged coaxially with each other on the optical axis.

  In the first projection optical system, it is preferable that the most magnified lens of the first optical system is an aspheric lens.

  Moreover, it is preferable that the lens located second from the magnification side of the first optical system is a lens arranged eccentrically with respect to the optical axis.

A second projection optical system according to the present invention is a projection optical system for enlarging and projecting an original image on a reduction-side conjugate plane onto an enlargement-side conjugate plane,
In order from the reduction side, a first optical system that forms an intermediate image conjugate with the original image, and a second optical system that forms a final image conjugate with the intermediate image on the enlargement-side conjugate surface, Arranged,
The first optical system comprises a plurality of lenses, and the second optical system comprises a reflecting mirror having a concave aspheric shape,
One of the plurality of lenses of the first optical system is a rotationally asymmetric free-form surface lens,
The other lenses other than the one lens of the first optical system and the reflection mirror of the second optical system are configured such that their optical surfaces are rotationally symmetric surfaces and are coaxially arranged on the optical axis. It is characterized by.

  In the second projection optical system, it is preferable that the most magnified lens of the first optical system is the rotationally asymmetric free-form surface lens.

  The projection display device according to the present invention includes a light source, a light valve, an illumination optical system for guiding a light beam from the light source to the light valve, and the first or second projection optical system according to the present invention. The light beam from the light source is modulated by the light valve and projected onto the screen by the projection optical system.

  The “rotationally symmetric surface” means a surface composed of a rotation surface (including a part lacking) about the rotation symmetry axis.

  The “optical axis” means a rotationally symmetric axis common to the largest number of optical surfaces among all optical surfaces in the entire system.

  The “rotationally asymmetric free-form surface lens” means a lens in which at least one of both surfaces is a rotationally asymmetric free-form surface (not a rotation surface).

  The “enlarged side” means the projected side (screen side), and the “reduced side” means the original image display area side (light valve side).

  Further, the “most magnified side” in the “lens on the most magnified side of the first optical system” means the most magnified side as an arrangement order on the optical axis, and means that it is closest to the screen in terms of distance. Not what you want.

  According to the projection optical system and the projection display apparatus of the present invention, the first optical system and the second optical system are arranged in order from the reduction side, and the first optical system has a plurality of lenses. The second optical system is configured to have a reflecting mirror having a concave aspherical shape, and is configured to form an intermediate image at a position between the first optical system and the second optical system. Therefore, a real image with less distortion can be formed on the enlargement-side conjugate surface even when the incident angle to the enlargement-side conjugate surface to be obliquely projected is large. In addition, since it is possible to use a single reflecting mirror for the second optical system, it is easy to assemble, and further, the overall length of the optical system can be shortened to promote downsizing of the apparatus.

  Further, since the intermediate image is formed at a position between the first optical system and the second optical system, a convex mirror is used for the second optical system, and the first optical system and the second optical system are used. The size of the reflecting mirror of the second optical system can be made smaller compared to a system configured not to form an intermediate image at a position between them.

  Further, all the optical surfaces of the first optical system and the second optical system are constituted by rotationally symmetric surfaces, and one lens of the first optical system and the reflecting mirror of the second optical system are arranged eccentrically, and the first optical system When other lenses in the system are arranged coaxially, various aberrations such as distortion, which are a concern when the overall length of the optical system is shortened or the size of the reflecting mirror is reduced, are satisfactorily corrected. Since the number of optical surfaces to be decentered can be limited to two, assembly is facilitated.

  On the other hand, one lens of the first optical system is constituted by a rotationally asymmetric free-form surface lens, and the other lenses of the first optical system and the reflection mirror of the second optical system are constituted by rotationally symmetric surfaces. In addition, according to the components arranged coaxially with each other, it becomes possible to satisfactorily correct various aberrations such as distortion by one free-form surface lens, and other optical surfaces other than this free-form surface lens are arranged coaxially. This makes it easy to assemble. Further, by configuring the lens surface with a free-form surface, it is possible to suppress adverse effects due to manufacturing errors on the optical performance as compared with the case where the reflection mirror is configured with a free-form surface.

1 is a diagram illustrating a configuration of a main part of a projection display apparatus according to Embodiment 1. FIG. 1 is a diagram illustrating a configuration of a projection optical system according to Example 1. FIG. 2 is a diagram illustrating in detail a configuration of a first optical system according to Example 1. FIG. It is a figure which shows the spot diagram (same figure A) and the distortion grating | lattice (same figure B) with respect to each light beam of d line, F line, and C line on the screen of the projection optical system which concerns on Example 1. FIG. 6 is a diagram illustrating a configuration of a main part of a projection display apparatus according to Embodiment 2. FIG. FIG. 6 is a diagram illustrating a configuration of a projection optical system according to Example 2. 6 is a diagram illustrating in detail a configuration of a first optical system according to Example 2. FIG. It is a figure which shows the spot diagram (the figure A) and the distortion grating (the figure B) with respect to each light beam of d line, F line, and C line on the screen of the projection optical system which concerns on Example 2. FIG. FIG. 10 is a diagram illustrating a configuration of a main part of a projection display apparatus according to a third embodiment. FIG. 6 is a diagram illustrating a configuration of a projection optical system according to Example 3. FIG. 6 is a diagram illustrating in detail a configuration of a first optical system according to Example 3. It is a figure which shows the spot diagram (same figure A) and the distortion grating | lattice (same figure B) with respect to each light beam of d line, F line, and C line on the screen of the projection optical system which concerns on Example 3. FIG. 1 is a diagram illustrating a configuration of an illumination optical system of a projection display apparatus according to Example 1. FIG.

  Hereinafter, embodiments of a projection optical system and a projection display apparatus according to the present invention will be described in detail. In the following description, first, the projection optical system according to Example 1 is used as a representative example (first embodiment) of the first projection optical system according to the present invention, and referring to FIGS. Next, the projection optical system according to Example 3 will be described as a representative example (second embodiment) of the second projection optical system according to the present invention, with reference to FIGS. 9 to 11 described above. To do. Further, the projection display apparatus according to the first embodiment will be described as a representative example of the embodiment of the projection display apparatus according to the present invention with reference to FIGS.

  As shown in FIGS. 1 to 3, the projection optical system 10 according to the first embodiment enlarges and projects an original image on the image display surface 3 which is a reduction-side conjugate surface onto a screen 5 which is an enlargement-side conjugate surface. A first optical system 1 comprising a plurality of (13) lenses, and a second optical system 2 comprising a reflecting mirror 4 having a concave aspherical shape. An intermediate image conjugate with the original image is formed between the first optical system 1 and the second optical system 2 by the first optical system 1, and the intermediate image is formed by the second optical system 2. A final image conjugate with the image is formed on the screen 5. A glass block 6 composed of a cover glass, a color synthesis prism, a light deflection prism, and the like is disposed on the enlargement side of the image display surface 3, and a diaphragm 7 (virtual diaphragm) is provided in the middle portion of the first optical system 1. Is arranged.

In addition, the projection optical system 10 includes a lens (a twelfth lens L ₁₂ ) positioned second from the magnification side among the plurality of lenses of the first optical system 1 and a reflection mirror 4 of the second optical system 2 such that the optical axis The other lenses of the first optical system 1 are arranged coaxially with each other on the optical axis Z (the other lenses are arranged in a tilted manner). Each rotational symmetry axis becomes the optical axis Z).

  As a result, distortion and the like can be corrected satisfactorily, and the number of optical members to be decentered is limited to two, so that the assembling accuracy of the projection optical system 10 can be increased and the assembling work is facilitated. . In particular, by decentering the reflecting mirror 4, it becomes possible to correct distortion aberration and the like, and by decentering the lens located second from the magnification side of the first optical system 1, the reflecting mirror 4 is decentered. Various aberrations caused by the correction can be corrected satisfactorily.

As a more preferred aspect, in the projection optical system 10, the most magnified lens (the thirteenth lens L ₁₃ ) of the first projection optical system 1 is composed of an aspheric lens whose both surfaces are aspheric. This makes it possible to correct distortion aberration and the like better.

  On the other hand, as shown in FIGS. 9 to 11, the projection optical system 10 of the second embodiment converts the original image on the image display surface 3, which is a conjugate surface on the reduction side, to the enlargement side, as in the first embodiment. The first optical system 1 including a plurality of (13) lenses, and a concave aspherical surface, are mounted on a front projection type projection display device 20 that performs enlarged projection on a screen 5 that is a conjugate surface. The first optical system 1 includes an intermediate image conjugate with the original image between the first optical system 1 and the second optical system 2. At the same time, the second optical system 2 forms a final image conjugate with the intermediate image on the screen 5.

The projection optical system 10 includes a free-form surface lens in which the most magnified lens (the thirteenth lens L ₁₃ ) among the plurality of lenses of the first optical system 1 is a rotationally asymmetric free-form lens. The optical surfaces of the lens and the reflecting mirror 4 of the second optical system 2 are rotationally symmetric surfaces and are coaxially arranged on the optical axis Z.

  Thereby, it becomes possible to correct | amend distortion aberration etc. favorably. Further, the number of free-form surface lenses is limited to one, and the other optical surfaces other than the free-form surface lens are arranged coaxially, so that the assembly accuracy of the projection optical system 10 can be increased, and the assembly work is facilitated. .

  1 and 13 is a front projection type device equipped with the above-described projection optical system 10, and as shown in FIG. 13, as a light source 15 and a light valve. Transmissive liquid crystal panels 11a to 11c, an illumination optical system 30 that guides the light beam from the light source 15 to the transmissive liquid crystal panels 11a to 11c, and the projection optical system 10 described above, and transmits the light beam from the light source 15 to the transmissive liquid crystal. The light is modulated by the panels 11 a to 11 c and projected onto the screen 5 shown in FIG. 1 by the projection optical system 10.

  The illumination optical system 30 includes dichroic mirrors 12 and 13 for color separation, a cross dichroic prism 14 for color synthesis, condenser lenses 16a to 16c, and total reflection mirrors 18a to 18c. Although not shown between the light source 15 and the dichroic mirror 12, the white light from the light source 15 is transmitted through the illumination optical system 30 corresponding to three color light beams (G light, B light, and R light), respectively. The light is incident on the liquid crystal panels 11 a to 11 c, modulated, and color-combined by the cross dichroic prism 14, and then incident on the projection optical system 10.

  In addition, the structure of the said illumination optical system 30 is made common to Examples 1-3 shown below, and abbreviate | omits description below. In addition, the projection optical system of the present invention is not limited to a use mode as a projection optical system of a projection display apparatus using a liquid crystal display panel, and the projection optical system of an apparatus using other light modulation means such as DMD. It can also be used as a system.

  Specific examples 1 to 3 of the projection optical system according to the present invention will be described below.

In the projection optical system 10 according to Examples 1 to 3 described below, the first optical system 1 includes three lens groups (first lens group G ₁ to third lens group G ₃ ). In the projection optical systems according to Examples 1 and 2 below, two of the plurality of optical surfaces constituting the first optical system 1 and the concave reflecting mirror 4 constituting the second optical system 2 are provided. It is aspherical. This aspheric shape is represented by the following aspheric formula (A).

  In the projection optical system according to Example 3 below, two of the plurality of optical surfaces constituting the first optical system 1 are rotationally asymmetric free-form surfaces. This free-form surface shape is represented by the following free-form surface formula (B).

<Example 1>
The configuration of the projection optical system 10 according to Example 1 is as shown in FIG. 2, and the detailed configuration of the first optical system 1 forming the projection optical system 10 is as shown in FIG. Further, the configuration of the main part of the projection display device 20 equipped with the projection optical system 10 according to the first embodiment is as shown in FIG.

  As shown in FIGS. 1 and 2, the projection optical system 10 of the present embodiment enlarges and projects an original image on an image display surface 3 which is a reduction-side conjugate surface onto a screen 5 which is an enlargement-side conjugate surface. The first optical system 1 composed of a plurality of lenses and the second optical system 2 composed of the reflecting mirror 4 having a concave aspherical shape. The intermediate image conjugate with the original image by the first optical system 1 Is formed between the first optical system 1 and the second optical system 2, and a final image conjugate with the intermediate image is formed on the screen 5 by the second optical system 2.

In the projection optical system 10, the reduction side of the entire system has telecentricity, and the second lens from the enlargement side (the 12th lens L ₁₂ ) among the plurality of lenses of the first optical system 1 is light. The reflecting mirror 4 of the second optical system 2 is arranged decentered and tilted with respect to the optical axis Z, and the other lenses of the first optical system 1 are placed on the optical axis Z. They are arranged coaxially with each other.

As shown in FIG. 3, the first optical system 1 includes three lens groups (first lens groups G ₁ to G ₁₎ that move in the direction of the optical axis Z while changing the distance from each other for focusing when the projection distance is changed. The third lens group G ₃ ).

The first lens group G ₁ includes, in order from the reduction side, a first lens L ₁ and a second lens L ₂ that are biconvex lenses, a third lens L _{3 that} is a biconcave lens, and a negative lens with a concave surface facing the enlargement side. the fourth lens L ₄ made of a meniscus lens, a fifth lens L ₅ which is a biconvex lens, a sixth lens L _6, which is a biconcave lens, a seventh lens L ₇ and the eighth lens L ₈ is a biconvex lens made by arranging a ninth lens L ₉ consisting of a negative meniscus lens having a concave surface facing the reduction side, the second lens L ₂ and third lens L _3, the fourth lens L ₄ and the fifth lens L _5, and eighth lens L ₈ and the ninth lens L ₉ constitute a cemented lens respectively are joined together. Further, 7 stop in the seventh lens L ₇ (virtual stop) is disposed.

The second lens group G ₂ includes, in order from the reduction side, and the tenth lens L ₁₀ made of a positive meniscus lens having a convex surface on the reduction side, an eleventh lens L ₁₁ is a biconcave lens, a convex surface on the reduction side by arranging the twelfth lens L ₁₂ consisting of a plano-convex lens directed, the third lens group G ₃ includes only a 13 lens L ₁₃ made of a non-spherical lens having both surfaces are both aspheric.

In the upper part of Table 1 below, the curvature radius R (unit: mm) of each member surface of the projection optical system 10 of Example 1, the distance D on the optical axis Z of each member (the air interval between the members and the center of each member) Thickness: Each surface position on a surface that does not exist on the optical axis Z (designed surface vertex position on the reflecting mirror 4 surface, and distance on the screen 5 surface in the optical axis Z direction from the surface vertex position is the minimum) The position obtained by dropping a perpendicular line from the position) onto the optical axis Z. The same applies to Examples 2 and 3 (unit: mm), showing the refractive index N _d and Abbe number ν _d of each member at the d line. . Further, the surface with * on the left side of the surface number represents an aspheric surface (the same applies to Tables 2 and 3).

Also, the middle part of Table 1, the shift to upward in the drawing with respect to the optical axis Z as a positive in the shift amount (Fig. 3 of the optical surface of the second lens L ₁₂ (surface number 23) (hereinafter The unit mm), the shift amount and the tilt amount (including the shift and tilt) of the optical surface (surface number 27) of the reflection mirror 4 and the optical axis Z The counterclockwise direction centering on the intersection is positive (hereinafter the same), in units of minutes.

Further, in the lower part of Table 1 below, intervals D ₁₈ , D ₂₄ , D ₂₆ , D ₂₇ (variables 1 to 4) that change for focusing according to the projection distance are shown. The distance D ₂₇ (variable 4) between the reflection mirror 4 and the screen 5 is shown as a negative value (hereinafter the same).

Further, the following Table 2, in each optical surface of the 13 lens _{L 13} of Example 1 (surface number 25, 26) and the aspheric expression representative of the aspherical shape of the reflection mirror 4 (surface number 27) (A) Each rotationally symmetric aspheric coefficient is shown.

  Further, as apparent from the spot diagram on the screen shown in FIG. 4 (FIG. A) and the distortion grid (Distortion Grid: B), the projection optical system 10 corrects chromatic aberration and distortion well. High performance projection optical system. The numerical values described on the right side of each spot diagram are the coordinate values on the image display surface 3 (the upper coordinate is the X coordinate value and the lower is the Y coordinate value) (FIG. 8 according to Examples 2 and 3). (Same in (A) and 12 (A)). The aspect ratio of the image display surface 3 is 4: 3 (the same applies to FIGS. 8B and 12B according to the second and third embodiments).

<Example 2>
The configuration of the projection optical system 10 according to the second embodiment is as shown in FIG. 6, and the detailed configuration of the first optical system 1 forming the projection optical system 10 is as shown in FIG. Further, the configuration of the main part of the projection display apparatus 20 equipped with the projection optical system 10 according to the second embodiment is as shown in FIG. 5-7, the same code | symbol is attached | subjected to the member which makes the effect similar to the thing of Example 1, and the description is abbreviate | omitted (It is the same in each figure which shows the structure of other Example 3). ).

  The configuration of the projection optical system 10 according to the second embodiment is substantially the same as that of the first embodiment.

In the upper part of Table 3 below, the curvature radius R (unit mm) of each member surface of the projection optical system 10 of Example 2, the interval D (unit mm) on the optical axis Z of each member, and the refraction of each member at the d-line. The rate N _d and the Abbe number ν _d are shown.
Also, the middle part of Table 3, the shift amount of each optical surface of the second lens _{L 12} shift amount (surface number 23) (Unit mm), the optical surface of the reflection mirror 4 (surface number 27) and Indicates the amount of tilt (unit: minutes).
Further, in the lower part of Table 3 below, intervals D ₁₈ , D ₂₄ , D ₂₆ , D ₂₇ (variables 1 to 4) that change for focusing according to the projection distance are shown.

Further, in Table 4, in each optical surface of the 13 lens _{L 13} of Example 2 (surface number 25, 26) and the aspheric expression representative of the aspherical shape of the reflection mirror 4 (surface number 27) (A) Each rotationally symmetric aspheric coefficient is shown.

  Further, as is apparent from the spot diagram on the screen shown in FIG. 8 (FIG. A) and the distortion grating (FIG. B), the projection optical system 10 has high performance capable of satisfactorily correcting chromatic aberration and distortion. Projection optical system.

<Example 3>
The configuration of the projection optical system 10 according to Example 3 is as shown in FIG. 10, and the detailed configuration of the first optical system 1 forming the projection optical system 10 is as shown in FIG. Moreover, the structure of the principal part of the projection display apparatus 20 equipped with the projection optical system 10 according to the third embodiment is as shown in FIG.

Although configuration of the projection optical system 10 according to the third embodiment is substantially the same as that of Example 1, and that the first twelfth lens L ₁₂ of the optical system 1 is a biconvex lens, the first optical system 1 The most magnified lens (the thirteenth lens L ₁₃ ) is a rotationally asymmetric free-form lens, and the other optical surfaces of the other lenses of the first optical system 1 and the reflecting mirror 4 of the second optical system 2 are rotated. It is different in that it is configured by a plane of symmetry and arranged coaxially with each other on the optical axis Z.

In the upper part of Table 5 below, the radius of curvature R (unit mm) of each member surface of the projection optical system 10 of Example 3, the interval D (unit mm) on the optical axis Z of each member, and the refraction of each member at the d-line. The rate N _d and the Abbe number ν _d are shown. Note that the surface with # on the left side of the surface number represents a rotationally asymmetric free-form surface.

In the lower part of Table 5 below, intervals D ₁₈ , D ₂₄ , D ₂₆ , D ₂₇ (variables 1 to 4) that change for focusing according to the projection distance are shown.

Furthermore, the upper part of the following Table 6, and the rotationally symmetric aspherical surface coefficients in the reflecting mirror 4 above aspheric formula representative of the aspherical shape of the (surface number 27) (A) of Example 3, each of the 13 lens L ₁₃ The rotationally symmetric aspherical coefficients in the free-form surface formula (B) representing the free-form surface shape of the optical surface (surface numbers 25 and 26) are shown.

Further, in the lower part of Table 6, each rotational asymmetrical aspherical surface coefficients in the free-form surface formula (B) representing the free curved surface shape of each optical surface (surface number 25) of the thirteenth lens L ₁₃ of Example 3 Show.

  Further, as is apparent from the spot diagram on the screen shown in FIG. 12 (FIG. A) and the distortion grating (FIG. B), this projection optical system 10 is capable of correcting chromatic aberration and distortion well. Projection optical system.

G ₁ ~G ₃ lens group L ₁ ~L ₁₃ lens R ₁ to R ₂₈ of curvature radius D ₁ to D ₂₇ Interval Z optical axis 1 first optical system 2 the second optical system 3 image display of each member faces of each member faces Surface 4 Reflective mirror 5 Screen 6 Glass block 7 Aperture 11a to 11c Transmission type liquid crystal panel 12, 13 Dichroic mirror 14 Cross dichroic prism 15 Light source 16a to 16c Condenser lens 18a to 18c Total reflection mirror 20 Projection display device 30 Illumination optical system

Claims (6)

A projection optical system for enlarging and projecting an original image on a reduction-side conjugate plane onto an enlargement-side conjugate plane,
In order from the reduction side, a first optical system that forms an intermediate image conjugate with the original image, and a second optical system that forms a final image conjugate with the intermediate image on the enlargement-side conjugate surface, Arranged,
The first optical system comprises a plurality of lenses, and the second optical system comprises a reflecting mirror having a concave aspheric shape,
All the optical surfaces constituting the first optical system and the second optical system are constituted by rotationally symmetric surfaces,
One lens of the plurality of lenses of the first optical system and the reflection mirror of the second optical system are arranged decentered with respect to the optical axis,
The other optical lenses other than the one lens of the first optical system are arranged coaxially with each other on the optical axis.   The projection optical system according to claim 1, wherein the most magnified lens of the first optical system is an aspheric lens.   3. The projection optical system according to claim 2, wherein the lens positioned second from the magnifying side of the first optical system is a lens arranged eccentrically with respect to the optical axis. A projection optical system for enlarging and projecting an original image on a reduction-side conjugate plane onto an enlargement-side conjugate plane,
In order from the reduction side, a first optical system that forms an intermediate image conjugate with the original image, and a second optical system that forms a final image conjugate with the intermediate image on the enlargement-side conjugate surface, Arranged,
The first optical system comprises a plurality of lenses, and the second optical system comprises a reflecting mirror having a concave aspheric shape,
One of the plurality of lenses of the first optical system is a rotationally asymmetric free-form surface lens,
The other lenses other than the one lens of the first optical system and the reflection mirror of the second optical system are configured such that their optical surfaces are rotationally symmetric surfaces and are coaxially arranged on the optical axis. A projection optical system characterized by that.   The projection optical system according to claim 4, wherein the most magnified lens of the first optical system is the rotationally asymmetric free-form lens. A light source, a light valve, an illumination optical system that guides a light beam from the light source to the light valve, and a projection optical system according to any one of claims 1 to 5, wherein the light beam from the light source is A projection display device, wherein light is modulated by a light valve and projected onto a screen by the projection optical system.

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