JP2003177351A - Projection optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection optical device which is made small-sized by using an eccentric prism as a projection optical system and devising a way of introducing illumination light into a reflection type display element. <P>SOLUTION: The projection optical device is equipped with the reflection type display element 1, the projection optical system 2 which projects an image displayed thereupon, and an illumination light source which lights up a display surface. The projection optical system 2 has a reflecting and refracting optical element 10 having two rotationally asymmetrical curved reflecting surfaces 12 and 13 with positive power or more; and the illumination light source is so arranged that a light beam exiting from the display surface and reaching a projection display surface and a light beam exiting from the illumination light source and reaching the display surface are both reflected up to the 2nd reflecting surface from the display surface side of the reflecting and refracting display element 10 and the axis 6 of projection light incident on the reflecting and refracting optical element 10 is not contained in a plane passing the optical axis 7 of projection light exiting from the reflecting and refracting optical element 10 and the center of the display surface. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection optical apparatus, and more particularly to a front projector for enlarging and projecting an image of a reflective display element on a wall surface or a screen.

[0002]

2. Description of the Related Art Conventional projectors use a rotationally symmetric lens system. In this case, a reflective display element such as a DMD (digital micromirror device) or a reflective LCD is used to obtain a bright display (for example,
In Japanese Patent Laid-Open No. 2000-98272), it is difficult to arrange an illumination optical path, and it is not easy to configure a small device.

Under these circumstances, there is a method in which the reflection type display element of PDLC or DMD is illuminated through all or part of a rotationally symmetric projection lens system.
And Japanese Patent Laid-Open No. 8-251520.

In a head-mounted image display device using a decentered prism, which is not a projection optical system, a reflective LC
Japanese Patent Application Laid-Open No. 11-337863 proposes a method of illuminating D through a reflecting surface and a transmitting surface of a part of a decentered prism.

Incidentally, Japanese Patent Application Laid-Open No. 2000-111800 discloses an image forming optical system using a prism having two decentered prisms, and a prism having an optical path intersecting with the prism on the image plane side.

[0006]

The reflection type display device can provide a bright display screen with a high aperture ratio, but it has a problem of interference between the illumination light path and the projection light path, and in particular DM.
In the D element, it is necessary to introduce the illumination from an oblique direction, which makes it difficult to downsize the projection optical system.

The present invention has been made in view of such problems of the prior art, and its object is to introduce illumination light into a reflection type display element by using a decentered prism as a projection optical system. An object of the present invention is to provide a projection optical device which is downsized by devising the device.

[0008]

A first projection optical apparatus of the present invention that achieves the above object comprises a reflective display element, a projection optical system for projecting an image displayed on the reflective display element,
In a projection optical device including an illumination light source that illuminates the display surface of the reflective display element, the projection optical system includes at least two reflective surfaces, and at least one of the reflective surfaces has a power for a light beam. A catadioptric optical element having a positive power, which is formed of a rotationally asymmetric curved reflecting surface having a decentering aberration correcting function and is arranged facing the display surface of the reflective display element. Or, having a reflective optical element, the light rays coming out of the display surface to the projection display surface, and the light rays coming out of the illumination light source to the display surface,
The illumination light source is arranged so as to reflect at least the second reflection surface counting from the display surface side of the catadioptric optical element or the display surface side of the reflection optical element together, and A light ray in the illumination light flux that reaches the center of the display surface, the central light ray of the illumination light flux is the illumination light optical axis, and a light ray that exits the display surface center and passes through the pupil center to the projection display surface is the projection light optical axis. In this case, the illumination light optical axis incident on the catadioptric optical element or the catoptric optical element is not included in the plane passing through the projection light optical axis emitted from the catadioptric optical element or the catoptric optical element and the display surface center. like,
The illumination light source is arranged.

A second projection optical device of the present invention which achieves the above object, comprises a reflective display element, a projection optical system for projecting an image displayed on the reflective display element, and display of the reflective display element. In a projection optical device provided with an illumination light source for illuminating a surface, the reflection type display element changes an inclination angle of a minute mirror of a large number of pixels arranged two-dimensionally to change an emission angle of reflected light. The projection optical system includes at least two reflective surfaces, at least one of which is provided.
The two reflecting surfaces are curved surfaces that give power to the luminous flux,
It is composed of a rotationally asymmetric curved reflective surface having an eccentric aberration correction function, and has a catadioptric optical element or a catadioptric optical element having a positive power arranged facing the display surface of the reflective display element, The light rays coming out of the display surface to the projection display surface and the light rays coming out of the illumination light source to the display surface are
The illumination light source is arranged so as to reflect together at least the first reflection surface counting from the display surface side of the catadioptric optical element or the display surface side of the reflection optical element, and the illumination light flux from the illumination light source. When the ray reaching the center of the display surface inside is the central ray of the illumination light flux as the illumination light optical axis, and the ray exiting the center of the display surface and passing through the pupil center to the projection display surface is the projection optical axis , The illumination light optical axis incident on the catadioptric optical element or the catoptric optical element is not included in a plane passing through the projection light optical axis emitted from the catadioptric optical element or the catoptric optical element and the display surface center. The illumination light source is arranged.

Hereinafter, the reason why the above configuration is adopted and the operation thereof will be described.

The projection optical apparatus of the present invention projects an image displayed on a reflective display element, and comprises a projection optical system and an illumination light source for illuminating the display surface of the reflective display element.

As the projection optical system, at least two reflecting surfaces are provided, and at least one of the reflecting surfaces has a curved surface shape that gives power to the light flux, and has a decentering aberration correcting function. It includes a catadioptric optical element or a catadioptric element having a positive power, which is composed of an asymmetric curved reflecting surface, and the optical element is arranged facing the display surface of the reflective display element.

Here, as the catadioptric optical element, JP-A Nos. 11-337863 and 2000-111800 are available.
Refers to a decentered prism having two or more curved reflective surfaces that have power and internally reflect, and a reflective optical element is such a reflective surface composed of a surface mirror. Then, they are arranged in the air in a predetermined positional relationship.

The rotationally asymmetric curved reflecting surface having a curved surface shape for giving power to the light flux and having a function of correcting eccentric aberration generally has a surface shape defined by a free curved surface. The surface shape of such a free-form surface is, for example, US Pat. No. 6,124,989 (JP 2000-66105 A).
It is a free-form surface defined by equation (a).

In the first projection optical device of the present invention, the reflective display element is not particularly limited, but in the second projection optical device of the present invention, a large number of pixels arranged two-dimensionally are used. It is assumed that a reflection type display element is used in which an on / off state is created by changing the inclination angle of the micro mirror and changing the emission angle of the reflected light.

Such a reflective display element is known as a DMD (Digital Micromirror Device) and is described in "Optics" (vol.25, No.6, p.313 to 314, 1996). As described above, each pixel arranged two-dimensionally is composed of minute mirrors, and the tilt of the minute mirrors is controlled by the electrostatic field action of the memory element arranged immediately below each pixel to reflect the reflected light. It is a reflective display element that creates an on / off state by changing an angle. When the pixel is off, the reflected light from the micro mirror of the pixel does not enter the projection optical system, and when the pixel is on, the reflected light from the micro mirror of the pixel enters the projection optical system. It is necessary to arrange the optical system components so as to form an image on the. The tilt angle of the micro mirror of each pixel when it is turned on is determined to be about 10 ° with respect to the incident surface of the DMD light beam.

Then, a ray of light from the display surface of the reflective display element to the projection display surface and a ray of light from the illumination light source to the display surface of the reflective display element are reflected by the catadioptric optical element or the reflective optical element. Count from the display surface side in the order that the projection rays pass,
In the first projection optical apparatus of the present invention, at least 2
In the second projection optical apparatus of the present invention, the illumination light source is arranged so that the reflecting surfaces up to the first reflecting surface are reflected together with at least the first reflecting surface.

That is, at least the second reflecting surface of the catadioptric optical element or the reflecting optical element arranged facing the display surface of the reflective display element, or the illumination light and the projection light through the first reflecting surface. Is reflected, illuminates the display surface, and projects the display image, a part of the optical system is shared by the illumination optical path and the projection optical path.

In any case, the light beam reaching the center of the display surface in the illumination light beam from the illumination light source is the center light beam of the illumination light beam as the illumination optical axis, and exits the center of the display surface and passes through the center of the pupil. When the ray reaching the projection display surface is used as the projection light optical axis, the illumination light optical axis incident on the catadioptric optical element or the catoptric optical element is projected light light emitted from the catadioptric optical element or catoptric optical element according to the present invention. The illumination light source is arranged so as not to be included in a plane passing through the axis and the center of the display surface.

Such an illumination light optical axis means that a catadioptric optical element or a catadioptric optical element configured as a decentered optical system has a decentering direction of each reflecting surface, except in the case of a special decentering configuration. It is in the direction of a plane passing through the optical axis of the projection light emitted from the optical element or the reflective optical element and the center of the display surface. When the illumination light optical axis incident on the catadioptric optical element or the catoptric optical element is present in this surface, the effective surface in the decentering direction of each reflecting surface must be made large for the illumination optical path and the projection optical path.
The catadioptric optical element or the catadioptric element becomes large, or a part of the light beam is vignetted, which makes it difficult to project a bright and uniform image.

On the other hand, the illumination light optical axis incident on the catadioptric optical element or the catoptric optical element is included in the plane passing through the projection light optical axis emitted from the catadioptric optical element or the catoptric optical element and the center of the display surface. If this is not done, the effective surface direction, which must be increased for the illumination light path and the projection light path on each reflecting surface, is generally the direction intersecting the eccentric direction, so that the catadioptric optical element or the catoptric optical element becomes larger. Does not connect to.

In particular, the catadioptric optical element or the catadioptric optical element comprises a first decentered prism having two reflecting surfaces, and the projection reflected from the reflecting surface that emerges from the display surface and first enters the optical axis of the projection light. Projection light reflected by the second reflecting surface when the projection light optical axis reflected by the second reflecting surface is projected on a plane including the light optical axis and the projection light optical axis incident on the reflecting surface If the decentering prism is configured so that the image of the optical axis intersects with the projection optical axis reflected by the first incident reflecting surface in the prism, this decentering prism applies positive power to each reflecting surface. Since it is a type of prism that disperses, the curved surface shape of each reflecting surface becomes weaker when the power of the same decentering prism is used, so the effective diameter is increased in the direction intersecting the decentering direction without increasing the size of the prism. Can be taken and is preferred

This point will be described by taking the projection optical system of Example 1 described later as an example. 1 shows a DMD 1 used as a reflective display element, a projection optical system 2 for projecting an image displayed on the DMD 1, and a decentering prism 10 of the projection optical system 2 for projecting light from the illumination light source 3 shown in FIG. FIG. 3 is a perspective view of an optical system portion including an illumination light introducing prism 30 that is incident on a front surface as viewed from obliquely above, in which the projection optical system 2 includes a decentering prism 10 and a decentering prism 20, and the DMD 1 includes most of the decentering prism 10. Can not be seen because it is hidden, but it can be seen from the perspective view seen from the same direction in FIG. 2 that the DMD 1 is arranged on the back side of the decentering prism 10 in the figure. Figure 3
1 is a front perspective view seen from the front side of FIGS. 1 and 2. FIG.
The projection display surface 5 (FIG. 5) such as a screen for projecting the display image of the DMD 1 by the projection optical system 2 is arranged in the −Z direction of the coordinates shown in FIG.

In this example, in the decentering prism 10,
The surface ABCD is an incident surface 11 on which the display light from the DMD 1 is incident, the surface EFGH is a first reflective surface 12 that reflects the display light incident on the incident surface 11 into the prism, and the surface IJBA is a display reflected on the first reflective surface 12. The second reflecting surface 13 for reflecting light and the surface HGCD are the emitting surfaces 14 for emitting the display light reflected by the second reflecting surface 13 to the outside of the prism. In the decentering prism 20, the surface KLOM is emitted from the decentering prism 10. An incident surface 21 for allowing display light to enter the prism,
The surface PQOM is a reflection surface 22 that reflects the display light that has entered the prism from the entrance surface 21, and the surface KLQP is an exit surface 23 that outputs the display light that is reflected by the reflection surface 22 to the outside of the prism.

A diaphragm 4 which forms a pupil of the projection optical system 2 is arranged between the decentering prism 10 and the decentering prism 20, and the shape of the diaphragm 4 is not always correct for illumination light. Are not shown.

An illumination light introducing prism 30 having a reflecting surface facing the exit surface 14 of the decentering prism 10 is arranged.
The illumination light source 3 is arranged on the incident side (FIG. 3).

In this arrangement, the axial principal ray (optical axis) from the illumination light source 3 intersects the incident surface of the illumination light introducing prism 30 at the point a and enters the illumination light introducing prism 30, and its reflecting surface. The illumination light optical axis which is incident on the point b, is reflected, exits the illumination light introducing prism 30 at the point c, is incident on the exit surface 14 of the eccentric prism 10 at the same point c, and enters the eccentric prism 10 is The light enters the point d on the second reflecting surface 13 and is reflected, then enters and reflects on the point e on the first reflecting surface 12, and enters the point f on the entrance surface 11 of the decentering prism 10 and enters the decentering prism 10. The DMD1 display surface is illuminated when the illumination light optical axis is incident on the screen center g of the DMD1 from the diagonal direction of the DMD1 at an angle of about 20 ° with respect to the normal direction.

The optical axis of the projection light projected from the screen center g of the DMD 1 in the normal direction is incident on the point h of the incident surface 11 of the eccentric prism 10 and enters the eccentric prism 10, and the first reflection surface 1 thereof.
It is incident on and reflected by the second point i, and then the second reflecting surface 13
Is incident on the point j of the decentered prism 10 to be reflected, and then is incident on the point k of the exit surface 14 of the decentered prism 10 to go out of the decentered prism 10 to pass through the center of the diaphragm 4 and this time, the incident surface 2 of the decentered prism 20.
1 enters the eccentric prism 20 and enters the eccentric prism 20, enters the reflecting surface 22 at a point m, is reflected, and then enters an exit surface 23 of the eccentric prism 20 at a point n. Then, it reaches a projection display surface (not shown) and projects a magnified image of the display image of the DMD 1.

Here, according to the present invention, the decentering prism 1
The illumination light optical axis incident on the point c which is the illumination light optical axis incident on 0 is the plane passing through the projection light optical axis emitted from the point k of the eccentric prism 10 and the display surface center g (point g and the point in FIG. 3). through k Fig. 3
By arranging the illumination light source 3 so that the illumination light source 3 is not included in the surface (perpendicular to the plane), the illumination light can be guided to the DMD 1 without making the decentering prism 10 large, and the projection optical device can be miniaturized. be able to.

In the case of FIGS. 1 to 3, in addition to the decentering prism 10, the projection optical system 2 is provided on the side where the projection light beam exits from the decentering prism 10 in order to sufficiently correct aberrations and project an enlarged projection image. Although the decentered prism 20 is arranged as another optical system, the other optical system is not limited to the decentered prism, and a rotationally symmetrical refracting optical system may be arranged.

The decentering prism arranged on the exit side of the decentering prism 10 has at least one reflecting surface, and the reflecting surface has a curved surface shape for giving power to a light beam, and has a rotationally asymmetrical function having a decentering aberration correcting function. It is possible to use the one having a curved reflecting surface.

In each of the first decentering prism 10 and the second decentering prism 20, the projection light optical axis in the prism is included in the plane, and the projection light optical axis in the first decentering prism 10 is The included plane may be parallel to the plane in which the projection optical axis of the second decentering prism 20 is included, or the planes may be rotated by 45 ° with respect to each other. In the latter case, the reflection type display element (FIG.
In the case of FIG. 3, it is necessary to rotate the DMD 1) around the projection optical axis.

Like the first decentering prism 10, the second decentering prism 20 also has two reflecting surfaces, and the projection optical axis is within a plane including the projection optical axis in the second decentering prism 20. May be configured to intersect with each other, or one reflective surface may be provided.

The present invention can also be applied to the case where a reflective liquid crystal display element is used as the reflective display element.

Further, as a reflection type display element, a reflection type display element for making an on / off state by changing the inclination of micro mirrors of a large number of pixels arranged two-dimensionally to change the emission angle of reflected light. That is, when the DMD is used, if the DMD is arranged so that the direction of deflection of the reflected light by the micro mirror is orthogonal to the plane including the projection light optical axis in the first decentering prism, the illumination light incident on the DMD The optical axis is not included in the plane that passes through the optical axis of the projection light emitted from the DMD and the center of the display surface of the DMD.

When the projection optical system is composed of the first decentering prism and the second decentering prism, the optical properties of the transparent medium forming the first decentering prism and the transparent medium forming the second decentering prism are different. Is desirable.

In a projection optical system which is composed of two decentered prisms having a rotationally asymmetric reflection surface and does not form an intermediate image, the diaphragm can be arranged near the center of the optical system to improve symmetry. Although monochromatic aberrations such as coma are improved, the chromatic aberration due to the chromatic dispersion of the refractive index, especially the chromatic aberration of magnification, is the prism surface shape because the entrance surface and the exit surface of each prism are both refracting surfaces. As a result, even a rotationally asymmetric free-form surface cannot be corrected. In particular, when the optical system is downsized, the wavelength becomes relatively large, and it becomes difficult to correct the chromatic aberration of magnification.

Therefore, in the present invention, the chromatic aberration, particularly the lateral chromatic aberration, is corrected by making the optical properties of the transparent medium forming the first decentering prism and the transparent medium forming the second decentering prism different. I am trying to do it. By making the optical properties of the decentered prisms different from each other in this way, it becomes possible to satisfactorily correct chromatic aberration due to dispersion at the refracting surface of the prism, particularly chromatic aberration of magnification.

Here, the optical properties of the transparent medium are specifically the refractive index and the Abbe number, but at least one of them must be different.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION The projection optical apparatus of the present invention will be described below based on embodiments, particularly focusing on the projection optical system.

First, the way of obtaining the coordinates in the following embodiments is as follows. As shown in FIGS. 1 to 3, when the projection optical system 2 is viewed from the projection display surface (screen) side on which the image is projected, the backward ray tracing projection is performed. The optical optical axis 7 is the final surface of the projection optical system 2 (the second surface in FIGS. 1 to 3).
The direction toward the exit surface 23) of the eccentric prism 20 (front direction) is the positive direction of the Z axis, the direction from the right to the left in the horizontal direction (left-right direction) is the positive direction of the X axis, and the vertical direction is from the bottom to the top. The direction (vertical direction) is the plus direction of the Y axis, and the origin of the optical system is the point where the projection optical axis 7 intersects the final surface of the projection optical system 2. The following description will be made in the order of the backward ray tracing. Hereinafter, description will be given with reference to the drawings.

In the first to sixth embodiments, the first backward ray tracing is performed.
The image of the reflective display element 2 is enlarged and projected on the projection display surface 5 at a position of 1200 mm from the surface (the final surface of the projection optical system 2), and the size of the projected image is 730.0 × 547.5.
mm (diagonal length 36 inches), the entrance pupil diameter is set to φ7 mm, and the size of the reflective display element 2 is 13.61 × 1.
0.21 mm is used.

Example 1 In this example, it is assumed that a DMD is used as the reflective display element 1. In FIG. 1, the projection optical system 2 is viewed obliquely from above on the projection display surface 5 (FIG. 5) side. 2 is a perspective view of FIG.
3 is a perspective view seen from the same direction, and FIG. 3 is a front perspective view seen from the front side of FIGS. 1 and 2. Also, FIG.
3 shows a YZ sectional view of the projection optical system 2. Further, FIG. 5 shows a schematic perspective view of the entire apparatus using the projection optical system of this embodiment.

The projection optical system 2 of this embodiment comprises a second decentering prism 20, a diaphragm 4, and a first decentering prism 10 from the projection display surface 5 side.
The reflection type display element 1 is arranged facing the optical axis 1, and the illumination light introducing prism 30 is arranged at a position deviated from the position where the projection light optical axis 7 of the exit surface 14 of the first decentering prism 10 passes. The first decentering prism 10 includes an incident surface 11 facing the reflective display element 1, a first reflecting surface 12 that reflects the display light that enters the prism from the incident surface 11, and a display light that is reflected by the first reflecting surface 12. The first decentered prism 10 has the same Y-axis as the projection light optical axis 7 and is composed of a second reflection surface 13 for reflection and an emission surface 14 for emitting the display light reflected by the second reflection surface 13 to the outside of the prism. The projection light optical axis 7 that is reflected so as to be included in the -Z plane and goes from the incident surface 11 to the first reflection surface 12 and the projection light optical axis 7 that goes from the second reflection surface 13 to the exit surface 14 are inside the prism. Cross at.

The second decentering prism 20 has an incident surface 21 for allowing the display light emitted from the first decentering prism 10 to enter the prism, a reflecting surface 22 for reflecting the display light entering the prism from the incident surface 21, and a reflection. The second decentering prism 20 is formed so that the projection light optical axis 7 is reflected so as to be included in the same YZ plane. It

Therefore, the projection optical axis 7 from the reflection type display element 1 to the projection display surface 5 exists in the same YZ plane.

Further, the illumination light optical axis 6 of the illumination light from the illumination light source 3 enters the exit surface 14 of the first decentering prism 10 through the illumination light introducing prism 30 and enters the first decentering prism 10. The optical axis is sequentially reflected by the second reflecting surface 13 and the first reflecting surface 12, goes out from the incident surface 11, and is at an angle of about 20 ° with respect to the normal direction at the screen center of the reflective display element 1. The display surface of the reflective display element 1 is illuminated so that the light enters from the diagonal direction of the reflective display element 1. Therefore, the reflective display element 1 is arranged so as to be inclined by 45 ° around the projection light optical axis 7 on which the first decentering prism 10 is incident. The optical axis 6 of the illumination light incident on the exit surface 14 of the first decentering prism 10 is projected from the reflective display element 1 to the projection display surface 5.
Is not included in the YZ plane including the projection light optical axis 7 up to and is arranged so as to enter the exit surface 14 from a position deviated in the -X direction. Then, the reflective display element 1 is arranged at an angle of 45 ° around the projection light optical axis 7 that is incident on the projection optical system 2, and the projection image optical axis where the projection image is emitted from the projection optical system 2 on the projection display surface 5. In order to compensate for the 45 ° tilt around 7 the entire optical system is tilted 45 ° in the opposite direction around the projection optical axis 7 exiting the projection optical system 2 (FIG. 5).

The second decentering prism 20 and the first embodiment of this embodiment
Each of the surfaces 21 to 23 and 11 to 14 of the decentering prism 10 is a decentered free-form surface.

The constituent parameters of the projection optical system 2 of this embodiment will be described later.

Example 2 This example assumes that a DMD is used as the reflective display element 1, and FIG. 6 shows a YZ sectional view of the projection optical system 2 of this example. Further, FIG. 7 shows a schematic perspective view of the entire apparatus using the projection optical system 2.

The projection optical system 2 of this embodiment comprises, from the projection display surface 5 side, a positive-power coaxial refraction optical system 20 'composed of two meniscus lenses having convex surfaces facing the projection display surface 5, an aperture stop 4, and a fourth optical element. The first decentering prism 10 includes the first decentering prism 10, the first decentering prism 10 is a decentering prism having the same shape as that of the first embodiment, and the reflection type display element 1 is disposed facing the incident surface 11. Although not shown, the illumination light introducing prism 30 is arranged at a position deviated from the position where the projection light optical axis 7 of the exit surface 14 passes, though it is not shown.
The first decentering prism 10 includes an incident surface 11 facing the reflective display element 1, a first reflecting surface 12 that reflects the display light that enters the prism from the incident surface 11, and a display light that is reflected by the first reflecting surface 12. Second reflecting surface 13 for reflecting, second reflecting surface 13
Exit surface 14 for exiting the display light reflected by the outside of the prism
In the first decentered prism 10, the projection light optical axis 7 is reflected so as to be included in the same YZ plane, and the projection light optical axis going from the incident surface 11 to the first reflection surface 12 is formed. 7 and the projection optical axis 7 from the second reflecting surface 13 toward the exit surface 14 intersect within the prism.

The illumination light optical axis 6 of the illumination light from the illumination light source 3 (not shown) enters the exit surface 14 of the first decentering prism 10 through the illumination light introducing prism 30 and enters the first decentering prism 10. The illumination light optical axis is the second reflection surface 1
3. The reflective display element 1 is sequentially reflected by the first reflective surface 12, goes out from the incident surface 11, and forms an angle of about 20 ° with respect to the normal direction at the screen center of the reflective display element 1. The display surface of the reflective display element 1 is illuminated so as to enter from the diagonal direction. Therefore, the reflective display element 1 is arranged so as to be inclined by 45 ° around the projection light optical axis 7 on which the first decentering prism 10 is incident. In addition, the exit surface 1 of the first decentering prism 10
The illuminating light optical axis 6 that is incident on 4 is not included in the YZ plane that includes the projection light optical axis 7 that extends from the reflective display element 1 to the projection display surface 5, and is emitted from a position deviated in the -X direction. It is arranged so as to be incident on the surface 14. Then, the reflective display element 1 is rotated about 45 degrees around the projection optical axis 7 which is incident on the projection optical system 2.
The entire optical system is inclined from the projection optical system 2 in order to compensate for the inclination of 45 ° around the projection light optical axis 7 emitted from the projection optical system 2 on the projection display surface 5. It is arranged at an angle of 45 ° in the opposite direction around the projected projection optical axis 7 (Fig. 7).

Each surface 1 of the first decentering prism 10 of this embodiment
Each of 1 to 14 is composed of an eccentric free-form surface.

The constituent parameters of the projection optical system 2 of this embodiment will be described later.

Example 3 In this example, it is assumed that a reflective liquid crystal display element is used as the reflective display element 1. FIG. 8 shows a YZ sectional view of the projection optical system 2 of this example. Further, FIG. 9 shows a schematic perspective view of the entire apparatus using the projection optical system 2.

The projection optical system 2 of this embodiment comprises a second decentering prism 20, a diaphragm 4, and a first decentering prism 10 from the projection display surface 5 side, and both the second decentering prism 20 and the first decentering prism 10 are implemented. It is composed of a decentered prism having the same shape as in Example 1, the reflection type display element 1 is arranged facing the entrance surface 11 of the first decentered prism 10, and the projection optical axis of the exit surface 14 of the first decentered prism 10 is arranged. Although not shown, the illumination light introducing prism 30 is arranged at a position deviating from the position where 7 passes, as in the first embodiment.

The first decentering prism 10 is reflected by the incident surface 11 facing the reflective display element 1, the first reflecting surface 12 and the first reflecting surface 12 that reflect the display light incident from the incident surface 11 into the prism. The first decentering prism 1 is composed of four surfaces, that is, a second reflecting surface 13 for reflecting the display light and an exit surface 14 for emitting the display light reflected by the second reflecting surface 13 to the outside of the prism.
At 0, the projection light optical axis 7 is reflected so as to be included in the same YZ plane, and the projection light optical axis 7 goes from the incident surface 11 to the first reflecting surface 12 and the second reflecting surface 13 to the exit surface. The optical axis 7 of the projection light traveling toward 14 intersects in the prism.

The second decentering prism 20 has an incident surface 21 for allowing the display light emitted from the first decentering prism 10 to enter the prism, a reflecting surface 22 for reflecting the display light entering the prism from the incident surface 21, and a reflection. The second decentering prism 20 is formed so that the projection light optical axis 7 is reflected so as to be included in the same YZ plane. It

Therefore, the projection optical axis 7 extending from the reflective display element 1 to the projection display surface 5 exists in the same YZ plane.

The illumination light optical axis 6 of the illumination light from the illumination light source 3 is incident on the exit surface 14 of the first decentering prism 10 via the illumination light introducing prism 30 and enters the first decentering prism 10. The optical optical axis is sequentially reflected by the second reflecting surface 13 and the first reflecting surface 12, goes out from the incident surface 11, and forms a predetermined angle with respect to the normal direction at the screen center of the reflective display element 1. Then, the display surface of the reflective display element 1 is illuminated so as to enter the reflective display element 1 obliquely from the longitudinal and lateral directions. Therefore, in this embodiment, the reflective display element 1 is not arranged so as to be inclined around the projection light optical axis 7 on which the first decentering prism 10 is incident. In addition, the exit surface 1 of the first decentering prism 10
The illuminating light optical axis 6 that is incident on 4 is not included in the YZ plane that includes the projection light optical axis 7 that extends from the reflective display element 1 to the projection display surface 5, and is emitted from a position deviated in the -X direction. It is arranged so as to be incident on the surface 14. In this example,
Projection optical axis 7 for projecting the entire optical system from the projection optical system 2.
It is not necessary to place it at an angle around (Fig. 9).

The second decentering prism 20 and the first decentering prism of this embodiment
Each of the surfaces 21 to 23 and 11 to 14 of the decentering prism 10 is a decentered free-form surface.

The constituent parameters of the projection optical system 2 of this embodiment will be described later.

Example 4 This example assumes that a DMD is used as the reflective display element 1, and the projection optical system 2 of this example is shown in FIG.
The schematic perspective view of the whole apparatus using is shown.

The projection optical system 2 of this embodiment comprises a second decentering prism 20, a diaphragm 4, and a first decentering prism 10 from the side of the projection display surface 5, and both the second decentering prism 20 and the first decentering prism 10 are implemented. It is composed of a decentered prism having the same shape as in Example 1, the reflection type display element 1 is arranged facing the entrance surface 11 of the first decentered prism 10, and the projection optical axis of the exit surface 14 of the first decentered prism 10 is arranged. Although not shown, the illumination light introducing prism 30 is arranged at a position deviating from the position where 7 passes, as in the first embodiment.

The first decentering prism 10 is reflected by the incident surface 11 facing the reflective display element 1, the first reflecting surface 12 and the first reflecting surface 12 that reflect the display light incident on the inside of the prism from the incident surface 11. The first decentering prism 1 is composed of four surfaces, that is, a second reflecting surface 13 for reflecting the display light and an exit surface 14 for emitting the display light reflected by the second reflecting surface 13 to the outside of the prism.
In 0, the projection light optical axis 7 is reflected so as to be included in the same plane, and the projection light optical axis 7 goes from the incident surface 11 to the first reflection surface 12 and goes from the second reflection surface 13 to the exit surface 14. The projection light optical axis 7 intersects in the prism.

The second decentering prism 20 has an incident surface 21 for allowing the display light emitted from the first decentering prism 10 to enter the prism, a reflecting surface 22 for reflecting the display light entering the prism from the incident surface 21, and a reflection. The second decentering prism 20 is formed so that the projection light optical axis 7 is reflected so as to be included in the same YZ plane. It

However, in this embodiment, the plane including the projection light optical axis 7 in the second decentering prism 20 and the first
The second decentering prism 20 is arranged around the projection light optical axis 7 exiting from the first decentering prism 10 so as to form an angle of 45 ° with the plane in which the projection light optical axis 7 is included in the decentering prism 10.
The second decentering prism 20 and the first decentering prism 10 are arranged so as to have a rotated relationship.

The illumination light optical axis 6 of the illumination light from the illumination light source 3 is incident on the exit surface 14 of the first decentering prism 10 through the illumination light introducing prism 30 (not shown), and inside the first decentering prism 10. The optical axis of the illumination light entering the second reflection surface 1
3. The reflective display element 1 is sequentially reflected by the first reflective surface 12, goes out from the incident surface 11, and forms an angle of about 20 ° with respect to the normal direction at the screen center of the reflective display element 1. The display surface of the reflective display element 1 is illuminated so as to enter from the diagonal direction. Therefore, the reflective display element 1 is arranged so as to be inclined by 45 ° around the projection light optical axis 7 on which the first decentering prism 10 is incident. In addition, the exit surface 1 of the first decentering prism 10
The illumination light optical axis 6 that is incident on 4 is not included in the plane that includes the projection light optical axis 7 in the first decentering prism 10, and is arranged so as to enter the exit surface 14 from a position deviated from one side. ing. Then, the reflective display element 1 is arranged at an angle of 45 ° around the projection light optical axis 7 that is incident on the projection optical system 2,
In order to compensate for the tilt of the projected image on the projection display surface 5 by 45 ° around the projection optical axis 7 emitted from the projection optical system 2, the projection optical axis emitted from the first decentering prism 10 as described above. The second decentering prism 20 is arranged in a relationship in which the second decentering prism 20 is rotated by 45 ° around 7 (FIG. 10).

The second decentering prism 20 and the first decentering prism of this embodiment
Each of the surfaces 21 to 23 and 11 to 14 of the decentering prism 10 is a decentered free-form surface.

The constituent parameters of the projection optical system 2 of this embodiment will be described later.

Embodiments 5 and 6 In these embodiments, it is assumed that a DMD is used as the reflection type display element 1, and FIG. 11 is a schematic view of the entire apparatus using the projection optical system 2 of these embodiments. A perspective view is shown.

The projection optical system 2 of these examples comprises, from the projection display surface 5 side, a second decentering prism 20, a diaphragm 4, and a first decentering prism 10. The first decentering prism 10 is the same as that of the first example. The reflection type display element 1 is arranged so as to face the entrance surface 11 of the first decentering prism 10, and the projection optical axis 7 of the exit surface 14 of the first decentering prism 10 passes from the position. Although not shown, the illumination light introducing prism 30 is arranged at the deviated position as in the first embodiment.

The first decentering prism 10 is reflected by the incident surface 11 facing the reflective display element 1, the first reflecting surface 12 that reflects the display light that has entered the prism from the incident surface 11, and the first reflecting surface 12. The first decentering prism 1 is composed of four surfaces, that is, a second reflecting surface 13 for reflecting the display light and an exit surface 14 for emitting the display light reflected by the second reflecting surface 13 to the outside of the prism.
In 0, the projection light optical axis 7 is reflected so as to be included in the same plane, and the projection light optical axis 7 goes from the incident surface 11 to the first reflection surface 12 and goes from the second reflection surface 13 to the exit surface 14. The projection light optical axis 7 intersects in the prism.

The second decentering prism 20 has an incident surface 21 that allows the display light emitted from the first decentering prism 10 to enter the prism, and a first reflecting surface 22 that reflects the display light that enters the prism from the incident surface 21. , A second reflecting surface 23 for reflecting the display light reflected by the first reflecting surface 22, a second reflecting surface 2
Emission surface 2 for emitting the display light reflected by 3 to the outside of the prism
It is a decentering prism having four surfaces 4 and 4 and having the same shape as the first decentering prism 10. In the second decentering prism 20, the projection light optical axis 7 is reflected so as to be included in the same YZ plane.

However, in this embodiment, the plane including the projection optical axis 7 in the second decentering prism 20 and the first
The second decentering prism 20 is arranged around the projection light optical axis 7 exiting from the first decentering prism 10 so as to form an angle of 45 ° with the plane in which the projection light optical axis 7 is included in the decentering prism 10.
The second decentering prism 20 and the first decentering prism 10 are arranged so as to have a rotated relationship.

The illumination light optical axis 6 of the illumination light from the illumination light source 3 is incident on the exit surface 14 of the first decentering prism 10 through the illumination light introducing prism 30 (not shown), and inside the first decentering prism 10. The optical axis of the illumination light entering the second reflection surface 1
3. The reflective display element 1 is sequentially reflected by the first reflective surface 12, goes out from the incident surface 11, and forms an angle of about 20 ° with respect to the normal direction at the screen center of the reflective display element 1. The display surface of the reflective display element 1 is illuminated so as to enter from the diagonal direction. Therefore, the reflective display element 1 is arranged so as to be inclined by 45 ° around the projection light optical axis 7 on which the first decentering prism 10 is incident. In addition, the exit surface 1 of the first decentering prism 10
The illumination light optical axis 6 that is incident on 4 is not included in the plane that includes the projection light optical axis 7 in the first decentering prism 10, and is arranged so as to enter the exit surface 14 from a position deviated from one side. ing. Then, the reflective display element 1 is arranged at an angle of 45 ° around the projection light optical axis 7 that is incident on the projection optical system 2,
In order to compensate for the tilt of the projected image on the projection display surface 5 by 45 ° around the projection optical axis 7 emitted from the projection optical system 2, the projection optical axis emitted from the first decentering prism 10 as described above. The second decentering prism 20 is arranged in a relationship in which the second decentering prism 20 is rotated by 45 ° around 7 (FIG. 11).

These second decentering prisms 20 of this embodiment
And each surface 21 to 23, 11 to 1 of the first decentering prism 10.
Each of 4 is composed of an eccentric free-form surface.

The constituent parameters of the projection optical system 2 of these examples will be described later.

Next, constituent parameters of the projection optical system 2 of Examples 1 to 6 will be shown. In the configuration parameters of each embodiment, as shown in FIGS. 2 and 3, the projection light optical axis 7 is projected from the center of the display surface of the reflective display element 1 by the back ray tracing and the pupil 4 is detected.
It is defined by a ray that passes through the center and reaches the projection display surface 5. Then, in the backward ray tracing, the projection optical optical axis 7 is set with the origin (a vertex of the final surface) where the projection optical optical axis 7 extending from the projection display surface 5 to the projection optical system 2 intersects the final surface of the projection optical system 2. Is the positive direction of the Z axis in the direction toward the final surface of the projection optical system 2 (front direction), the positive direction of the X axis in the direction from right to left in the horizontal direction (horizontal direction), and upward from the vertical direction. The direction (vertical direction) is the plus direction of the Y axis.

For the eccentric surface, the amount of eccentricity from the center of the origin of the optical system to the top of the surface (X axis direction, Y axis direction, Z
Axial directions are X, Y, and Z, respectively, and the central axis of the surface (for the free-form surface, the Z axis of the expression (a) in the cited document below).
The tilt angles (α, β, γ (°)) about the X axis, the Y axis, and the Z axis, respectively, are given. In that case, positive α and β mean counterclockwise rotation with respect to the positive directions of the respective axes, and positive γ means clockwise rotation with respect to the positive direction of the Z-axis. The rotation of α, β, γ of the center axis of the surface is performed by rotating the center axis of the surface and its XYZ orthogonal coordinate system by α counterclockwise around the X axis, and then rotating the same. The center axis of the surface is β counterclockwise around the Y axis of the new coordinate system.
The coordinate system that is rotated by 1 degree is also rotated counterclockwise by β around the Y axis, and then the center axis of the surface that is rotated by 2 degrees is rotated around the Z axis of the new coordinate system of the new coordinate system. It rotates by γ clockwise.

Further, among the optical action surfaces forming the optical system of each embodiment, when a specific surface and the surface following the specific surface form a coaxial optical system, a surface spacing is given, and other surfaces are given. The radius of curvature, the refractive index of the medium, and the Abbe number are given according to the conventional method.

The shape of the surface of the free-form surface used in the present invention is, for example, the free-form surface defined by the equation (a) of US Pat. No. 6,124,989 (JP 2000-66105 A), The Z-axis of the defining equation becomes the axis of the free-form surface.

The term relating to the free-form surface for which no data is written is 0. Regarding the refractive index, those for the d-line (wavelength 587.56 nm) are shown. The unit of length is mm.

In the table of numerical data below, "FF
Reference character S denotes a free-form surface, and reference character RE denotes a reflection surface, where the object surface is the projection image surface 5 and the image surface is the display surface of the reflective display element 1.

Example 1 Surface Number Curvature Radius Surface Spacing Eccentricity Refractive Index Abbe Number Object Surface ∞ Eccentricity (1) 1 FFS 1.4924 57.6 2 FFS (RE) Eccentricity (2) 1.4924 57.6 3 FFS Eccentricity (3) 4 ∞ (Aperture surface) ) Eccentricity (4) 5 FFS Eccentricity (5) 1.4924 57.6 6 FFS (RE) Eccentricity (6) 1.4924 57.6 7 FFS (RE) Eccentricity (7) 1.4924 57.6 8 FFS Eccentricity (8) Image plane ∞ Eccentricity (9) FFS C ₄ 6.809 1 × 10 ^-3 C ₆ 8.9 914 × 10 ^-3 C ₈ -2.4721 × 10 ^-4 C ₁₀ 6.4722 × 10 ^-5 FFS C ₄ -1.059 ₄ × 10 ^-3 C ₆ 2.8085 × 10 ^-3 C ₈ -2.0276 × 10 ^-5 C ₁₀ 2.9571 x 10 ^-5 C ₁₁ -8.7851 x 10 ^-7 C ₁₃ -8.1133 x 10 ^-7 C ₁₅ 7.3249 x 10 ^-7 FFS C ₄ -4.7838 x 10 ^-3 C ₆ 1.5035 x 10 ^-2 C ₈ 1.0081 × 10 ⁻³ C ₁₀ −1.8708 × 10 ⁻⁴ FFS C ₄ 2.5890 × 10 ⁻² C ₆ 1.5953 × 10 ⁻² C ₈ 1.2005 × 10 ⁻³ C ₁₀ −1.4249 × 10 ⁻⁴ FFS C ₄ 6.1496 × 10 ^{− _{3 C 6 7.1308 × 10 -3 C}} 8 5.2260 × 10 -6 C 10 1.8362 × 10 -6 C 11 -1.1447 × 10 -6 C 13 -1.4625 × 10 -7 C 15 5.1726 × 10 - ⁷ FFS C ₄ -5.8591 × 10 ^-3 C ₆ 4.1503 × 10 ^-4 C ₈ -1.2559 × 10 ^-4 C ₁₀ 8.8654 × 10 ^-6 C ₁₁ -1.7472 × 10 ^-6 C ₁₃ -3.6838 × 10 ^-6 C ₁₅ 6.8 127 × 10 ^-7 FFS C ₄ -9.7353 × 10 ^-3 C ₆ 9.5723 × 10 ^-3 C ₈ -5.9950 × 10 ^-4 C ₁₀ -1.8043 × 10 ^-4 Eccentricity (1) X 0.00 Y 0.00 Z-1200.00 α 0.00 β 0.00 γ 45.00 Eccentricity (2) X 0.00 Y 0.00 Z 12.44 α -45.00 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 15.45 Z 12.44 α -90.00 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 25.36 Z 12.44 α- 90.00 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 26.36 Z 12.44 α -90.00 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 48.86 Z 12.44 α -112.50 β 0.00 γ 0.00 Eccentricity (7) X 0.00 Y 35.50 Z -0.92 α -157.50 β 0.00 γ 0.00 Eccentricity (8) X 0.00 Y 35.50 Z 21.85 α -180.00 β 0.00 γ 0.00 Eccentricity (9) X 0.00 Y 35.50 Z 23.57 α -180.00 β 0.00 γ -45.00.

Example 2 Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object plane ∞ Eccentricity (1) 1 ∞ 2 11.56 Eccentricity (2) 1.4875 70.4 3 8.02 Eccentricity (3) 4 8.71 Eccentricity (4) 1.5092 59.3 5 9.03 Eccentric (5) 6 ∞ (Throttle surface) Eccentric (6) 7 FFS Eccentric (7) 1.4924 57.6 8 FFS (RE) Eccentric (8) 1.4924 57.6 9 FFS (RE) Eccentric (9) 1.4924 57.6 10 FFS Eccentric (10) Image plane ∞ Eccentricity (11) FFS C ₄ -1.6269 × 10 ^-2 C ₆ -1.3958 × 10 ^-2 C ₈ 1.2005 × 10 ^-3 C ₁₀ 1.6587 × 10 ^-4 FFS C ₄ -5.5890 × 10 ^-3 C _{6- ^{4.2159 × 10 -3 C 8 7.2404 ×}} 10 -5 C 10 2.6520 × 10 -5 C 11 -4.3471 × 10 -7 C 13 -1.4172 × 10 -6 C 15 -1.2542 × 10 -6 FFS C 4 4.9701 × 10 - ³ C ₆ 4.8 760 x 10 ^-3 C ₈ 2.6570 x 10 ^-5 C ₁₀ -9.7540 x 10 ^-6 C ₁₁ -5.8319 x 10 ^-7 C ₁₃ -8.7007 x 10 ^-7 C ₁₅ -1.2780 x 10 ^-6 FFS C ₄ 1.9707 × 10 ^-2 C ₆ 2.1280 × 10 ^-2 C ₈ 2.8436 × 10 ^-4 C ₁₀ -4.68 98 × 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z-120 0.00 α 0.00 β 0.00 γ 45.00 Eccentricity (2) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 0.00 Z 6.11 α 0.00 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 0.00 Z 7.89 α 0.00 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 0.00 Z 9.80 α 0.00 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 0.00 Z 23.56 α 0.00 β 0.00 γ 0.00 Eccentricity (7) X 0.00 Y 0.00 Z 24.98 α 0.00 β 0.00 γ 0.00 Eccentricity (8) X 0.00 Y 0.00 Z 54.69 α -22.50 β 0.00 γ 0.00 Eccentricity (9) X 0.00 Y 15.82 Z 38.87 α -67.50 β 0.00 γ 0.00 Eccentricity (10) X 0.00 Y -11.56 Z 38.87 α -90.00 β 0.00 γ 0.00 Eccentricity (11) X 0.00 Y -14.04 Z 38.87 α -90.00 β 0.00 γ -45.00.

Example 3 Surface Number Curvature Radius Surface Spacing Eccentricity Refractive Index Abbe Number Object Surface ∞ Eccentricity (1) 1 FFS 1.4924 57.6 2 FFS (RE) Eccentricity (2) 1.4924 57.6 3 FFS Eccentricity (3) 4 ∞ (Aperture surface) ) Eccentricity (4) 5 FFS Eccentricity (5) 1.4924 57.6 6 FFS (RE) Eccentricity (6) 1.4924 57.6 7 FFS (RE) Eccentricity (7) 1.4924 57.6 8 FFS Eccentricity (8) Image plane ∞ Eccentricity (9) FFS C ₄ 9.3298 × 10 ^-3 C ₆ 9.2282 × 10 ^-4 C ₇ -2.6786 × 10 ^-5 C ₈ -4.9982 × 10 ^-5 C ₉ 2.5479 × 10 ^-4 C ₁₀ 2.4669 × 10 ^-4 FFS C ₄ -7.2942 × 10 ^-4 C ₆ 1.7 125 x 10 ^-3 C ₇ 4.4 980 x 10 ^-6 C ₈ 1.2 130 x 10 ^-5 C ₉ 1.9812 x 10 ^-5 C ₁₀ 2.4 264 x 10 ^-5 C ₁₁ -2.0 904 x 10 ^-7 C ₁₂ 2.9589 x 10 ^-7 C ₁₃ 3.5 188 x 10 ^-7 C ₁₄ 7.4 955 x 10 ^-7 C ₁₅ 1.050 1 x 10 ^-6 FFS C ₄ -1.567 1 x 10 ^-2 C ₆ 1.6491 x 10 ^-2 C ₇ 8.9 825 x 10 ^-5 C ₈ 5.7 132 x 10 ^-4 C ₉ -5.4764 x 10 ^-4 C ₁₀ -2.5398 x 10 ^-4 FFS C ₄ 1.060 ₄ x 10 ^-2 C ₆ 1.5130 x 10 ^-2 C ₇ 1.5781 x 10 ^-4 C ₈ 3.1048 x 10 ^-4 C ₉ -8.012 1 × 10 ^-4 C ₁₀ 2.1858 × 10 ^-5 FFS C ₄ 5.9 599 × 10 ^-3 C ₆ 8.9163 × 10 ^-3 C ₇ 1.3098 × 10 ^-5 C ₈ -7.0 396 × 10 ^-5 C ₉ -5.0955 × 10 ^-6 C ₁₀ 8.5524 × 10 ^-6 C ₁₁ 4.9139 × 10 ^-7 C ₁₂ -4.8582 × 10 ^-8 C ₁₃ 3.6872 × 10 ^-7 C ₁₄ -3.4003 × 10 ^-7 C ₁₅ 2.5281 × 10 ^-7 FFS C ₄ -6.7057 × 10 ^-3 C ₆ 4.3417 × 10 ^-3 C ₇ -1.4197 × 10 ^-5 C ₈ -2.7031 × 10 ^-4 C ₉ 1.0850 × 10 ^-4 C ₁₀ 1.4768 × 10 ^-4 C ₁₁ -5.3609 × 10 ^-7 C ₁₂ -2.5406 × 10 ^-6 C ₁₃ -5.9738 × 10 ^-6 C ₁₄ 3.5345 × 10 ^-6 C ₁₅ 2.8943 × 10 ^-6 FFS C ₄ -2.5519 × 10 ^-2 C ₆ 1.3790 × 10 ^-2 C ₇ 9.0713 × 10 ^-4 C ₈ -1.3777 × 10 ^-3 C ₉ 4.4602 × 10 ^-4 C ₁₀ 8.1 380 × 10 ^-4 Eccentricity (1) X 0.00 Y 0.00 Z-120 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 12.25 α -45.00 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 22.81 Z 12.25 α -90.00 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 33.48 Z 12.25 α -90.00 β 0.00 γ 0.00 Eccentricity (5 ) X 0.00 Y 42.96 Z 12.25 α -90.00 β 0.00 γ 0.00 Eccentricity (6) X 0 .00 Y 59.43 Z 12.25 α -112.50 β 0.00 γ 0.00 Eccentricity (7) X 0.00 Y 48.91 Z 1.74 α -157.50 β 0.00 γ 0.00 Eccentricity (8) X 0.00 Y 48.91 Z 20.83 α -180.00 β 0.00 γ 0.00 Eccentricity (9 ) X 0.00 Y 48.91 Z 23.08 α -180.00 β 10.00 γ 0.00.

Example 4 Surface Number Curvature Radius Surface Spacing Eccentricity Refractive Index Abbe Number Object Surface ∞ Eccentricity (1) 1 FFS 1.7552 27.6 2 FFS (RE) Eccentricity (2) 1.7552 27.6 3 FFS Eccentricity (3) 4 ∞ (Aperture surface) ) Eccentricity (4) 5 FFS Eccentricity (5) 1.5088 68.2 6 FFS (RE) Eccentricity (6) 1.5088 68.2 7 FFS (RE) Eccentricity (7) 1.5088 68.2 8 FFS Eccentricity (8) Image plane ∞ Eccentricity (9) FFS C ₄ 4.2989 × 10 ^-3 C ₅ -1.2883 × 10 ^-3 C ₆ 1.0182 × 10 ^-2 C ₇ 2.6155 × 10 ^-5 C ₈ 5.9167 × 10 ^-5 C ₉ 1.0709 × 10 ^-5 C ₁₀ -6.8 105 × 10 ^-5 FFS C ₄ -5.9749 x 10 ^-4 C ₅ -1.1772 x 10 ^-3 C ₆ 1.9769 x 10 ^-3 C ₇ -1.1223 x 10 ^-6 C ₈ -3.8718 x 10 ^-6 C ₉ -2.3494 x 10 ^-5 C ₁₀ 2.9728 x 10 ^-5 C ₁₁ -5.4885 x 10 ^-7 C ₁₂ -5.8200 x 10 ^-7 C ₁₃ 5.2841 x 10 ^-7 C ₁₄ -2.0975 x 10 ^-7 C ₁₅ 2.2 147 x 10 ^-7 FFS C ₄ -2.2464 x 10 ^-3 C ₅ -8.7840 x 10 ^-4 C ₆ -1.2 195 x 10 ^-2 C ₇ -2.7718 x 10 ^-4 C ₈ -5.2352 x 10 ^-4 C ₉ -3.7322 x 10 ^-5 C ₁₀ 4.8929 x 10 ^-4 FFS C _{4 ^{7.7146 × 10 -4 C 5 -3.3221 ×}} 10 -2 C 6 -4.6107 × 10 -3 C 7 -2.3980 × 10 -4 C 8 1.2005 × 10 -3 C 9 -1.9513 × 10 -4 C 10 7.3906 × 10 - ⁵ FFS C ₄ 5.3916 × 10 ^-3 C ₅ -8.5164 × 10 ^-4 C ₆ 4.8949 × 10 ^-3 C ₇ 6.1656 × 10 ^-6 C ₈ 3.8395 × 10 ^-5 C ₉ -3.8998 × 10 ^-5 C ₁₀ 1.3846 × 10 ^-6 C ₁₁ 6.9769 x 10 ^-7 C ₁₂ 8.9 109 x 10 ^-7 C ₁₃ -3.2507 x 10 ^-6 C ₁₄ -3.0 447 x 10 ^-8 C ₁₅ 7.4263 x 10 ^-7 FFS C ₄ -4.8608 x 10 ^-3 C ₅ 5.5089 x 10 ^-4 C ₆ -3.259 ⁴ x 10 ^-3 C ₇ 6.8152 x 10 ^-6 C ₈ -3.1111 x 10 ^-5 C ₉ -3.5032 x 10 ^-5 C ₁₀ -3.4 600 x 10 ^-5 C ₁₁ 3.2 365 x 10 ^-7 C ₁₂ 3.2 128 x 10 ^-6 C ₁₃ -3.4451 x 10 ^-6 C ₁₄ 2.7333 x 10 ^-6 C ₁₅ 5.6830 x 10 ^-7 FFS C ₄ 4.6699 x 10 ^-4 C ₅ 1.5730 x 10 ^-2 C ₆ 3.2156 x 10 ^-3 C ₇ -1.535 4 x 10 ^-5 C ₈ -3.2900 x 10 ^-4 C ₉ -1.3150 x 10 ^-3 C ₁₀ 4.3 665 x 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z -120 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 13.77 α -45.00 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 14.65 Z 13.77 α -90.00 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 17.71 Z 13.77 α -90.00 β 0.00 γ 45.00 Eccentricity (5) X 0.00 Y 18.71 Z 13.77 α -90.00 β 0.00 γ 45.00 Eccentricity (6) X 0.00 Y 41.49 Z 13.77 α -106.33 β -15.70 γ 42.73 Eccentric (7) X 9.21 Y 28.46 Z 4.55 α -149.64 β -40.79 γ 20.94 Eccentric (8) X -6.12 Y 28.46 Z 19.89 α -180.00 β -45.00 γ 0.00 Eccentric (9) X -6.95 Y 28.46 Z 20.71 α -180.00 β -45.00 γ -45.00.

Example 5 Surface Number Curvature Radius Surface Spacing Eccentricity Refractive Index Abbe Number Object Surface ∞ Eccentricity (1) 1 FFS 1.4875 70.4 2 FFS (RE) Eccentricity (2) 1.4875 70.4 3 FFS (RE) Eccentricity (3) 1.4875 70.4 4 FFS eccentricity (4) 5 ∞ (diaphragm surface) eccentricity (5) 6 FFS eccentricity (6) 1.5281 52.6 7 FFS (RE) eccentricity (7) 1.5281 52.6 8 FFS (RE) eccentricity (8) 1.5281 52.6 9 FFS eccentricity (8) 9) Image plane ∞ Eccentricity (10) FFS C ₄ 8.9607 × 10 ^-3 C ₅ -6.8680 × 10 ^-4 C ₆ 3.1200 × 10 ^-2 C ₇ -2.2704 × 10 ^-4 C ₈ 8.7887 × 10 ^-4 C ₉ 3.3485 × 10 ^-4 C ₁₀ -3.0776 × 10 ^-4 FFS C ₄ -7.0920 × 10 ^-3 C ₅ 7.8223 × 10 ^-4 C ₆ -7.2947 × 10 ^-3 C ₇ -2.7624 × 10 ^-5 C ₈ -1.6065 × 10 ^{_{-5 C 9 3.8935 × 10 -5 C}} 10 4.9827 × 10 -5 C 11 2.1185 × 10 -7 C 12 1.0801 × 10 -7 C 13 1.3385 × 10 -5 C 14 1.9531 × 10 -6 C 15 4.8432 × 10 - ⁶ FFS C ₄ 1.2147 × 10 ^-2 C ₅ 5.894 1 × 10 ^-4 C ₆ 1.0 360 × 10 ^-2 C ₇ -9.0553 × 10 ^-5 C ₈ 5.5037 × 10 ^-4 C ₉ 1.9906 × 10 ^-4 C ₁₀ -2.8358 x 10 ^-4 C ₁₁ -8.1 100 x 10 ^-6 C ₁₂ -9.8655 x 10 ^-6 C ₁₃ 3.852 2 x 10 ^-5 C ₁₄ 3.5845 x 10 ^-6 C ₁₅ 5.5724 x 10 ^-6 FFS C _{4 ^{-3.7478 × 10 -2 C 5 4.3638 ×}} 10 -3 C 6 -4.2695 × 10 -2 C 7 5.8617 × 10 -4 C 8 -1.2502 × 10 -3 C 9 -4.4465 × 10 -4 C 10 1.1549 × 10 - ³ FFS C ₄ -3.203 0 x 10 ^-2 C ₅ -2.6689 x 10 ^-2 C ₆ -3.6711 x 10 ^-2 C ₇ 1.6582 x 10 ^-4 C ₈ 1.2005 x 10 ^-3 C ₉ 2.1055 x 10 ^-3 C ₁₀ 6.7384 _{^{× 10 -4 FFS C 4 -5.1949 ×}} 10 -3 C 5 -4.7878 × 10 -4 C 6 -4.9258 × 10 -3 C 7 -1.9416 × 10 -5 C 8 2.1687 × 10 -5 C 9 4.3747 × 10 - ⁵ C ₁₀ 2.9404 x 10 ^-5 C ₁₁ -4.2660 x 10 ^-7 C ₁₂ 8.2 344 x 10 ^-7 C ₁₃ 5.9896 x 10 ^-8 C ₁₄ 1.0826 x 10 ^-6 C ₁₅ -7.6572 x 10 ^-8 FFS C ₄ 5.6793 x 10 ^-3 C ₅ -1.0769 x 10 ^-3 C ₆ 4.0807 x 10 ^-3 C ₇ -1.8251 x 10 ^-5 C ₈ -3.8749 x 10 ^-5 C ₉ 3.5780 x 10 ^-5 C ₁₀ -1.4815 x 10 ^-6 C ₁₁ -5.0377 x 10 ^-7 C ₁₂ 5.1151 x 10 ^-7 C ₁₃ 4.3297 x 10 ^-8 C ₁₄ 1.0385 x 10 ^-6 C ₁₅ -4.1980 x 10 ^-8 FFS C ₄ 2.6 410 x 10 ^-2 C ₅ -8.8970 × 10 ^-3 C ₆ 2.0898 × 10 ^-2 C ₇ -8.6245 × 10 ^-5 C ₈ -4.4155 × 10 ^-4 C ₉ 1.6185 × 10 ^-4 C ₁₀ 8.8770 × 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z-1200.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 19.43 α 22.50 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -13.63 Z 5.80 α 67.50 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 8.21 Z 5.80 α 90.00 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 12.41 Z 5.80 α 90.00 β 0.00 γ 45.00 Eccentricity (6) X 0.00 Y 13.41 Z 5.80 α 90.00 β 0.00 γ 45.00 Eccentricity (7) X 0.00 Y 44.59 Z 5.80 α 73.67 β -15.70 γ 42.73 Eccentricity (8) X -11.70 Y 28.03 Z -5.91 α 30.36 β -40.79 γ 20.94 Eccentricity (9) X 7.03 Y 28.03 Z 12.83 α 0.00 β -45.00 γ 0.00 Eccentricity (10) X 21.76 Y 28.03 Z 27.56 α 0.00 β -45.00 γ -45.00.

Example 6 Surface number Radius of curvature Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ Eccentricity (1) 1 FFS 1.7552 27.6 2 FFS (RE) Eccentricity (2) 1.7552 27.6 3 FFS (RE) Eccentricity (3) 1.7552 27.6 4 FFS Eccentric (4) 5 ∞ (Throttle surface) Eccentric (5) 6 FFS Eccentric (6) 1.4875 70.4 7 FFS (RE) Eccentric (7) 1.4875 70.4 8 FFS (RE) Eccentric (8) 1.4875 70.4 9 FFS Eccentric ( 9) Image plane ∞ Eccentricity (10) FFS C ₄ 5.1638 × 10 ^-3 C ₅ 5.0652 × 10 ^-5 C ₆ 4.3811 × 10 ^-3 C ₇ 1.3741 × 10 ^-6 C ₈ -1.6974 × 10 ^-5 C ₉ 1.3838 × 10 ^-5 C ₁₀ 3.2824 x 10 ^-6 FFS C ₄ 1.6 150 x 10 ^-3 C ₅ -5.4 130 x 10 ^-4 C ₆ 4.0839 x 10 ^-3 C ₇ 9.9564 x 10 ^-7 C ₈ -2.1304 x 10 ^-5 C ₉ 1.4346 x 10 ^-5 C ₁₀ -3.0124 x 10 ^-5 C ₁₁ -7.7491 x 10 ^-8 C ₁₂ 1.0349 x 10 ^-7 C ₁₃ 2.6473 x 10 ^-7 C ₁₄ -2.1943 x 10 ^-7 C ₁₅ 1.9439 x 10 ^-7 FFS C ₄ -3.1976 × 10 ^-3 C ₅ -8.3139 × 10 ^-4 C ₆ 1.7910 × 10 ^-3 C ₇ -8.7376 × 10 ^-6 C ₈ -2.8171 × 10 ^-5 C ₉ 6.0348 × 1 0 ^-6 C ₁₀ -1.0533 x 10 ^-5 C ₁₁ -6.6993 x 10 ^-7 C ₁₂ 3.1109 x 10 ^-7 C ₁₃ -1.5051 x 10 ^-6 C ₁₄ -9.4957 x 10 ^-8 C ₁₅ -2.7479 x 10 ^-7 FFS C ₄ 3.1422 × 10 ^-3 C ₅ 2.8723 × 10 ^-4 C ₆ 1.1404 × 10 ^-3 C ₇ -7.2869 × 10 ^-5 C ₈ -4.2283 × 10 ^-5 C ₉ 1.1974 × 10 ^-4 C ₁₀ -1.9637 × 10 ^-5 FFS C ₄ 4.1903 x 10 ^-3 C ₅ -1.7 103 x 10 ^-2 C ₆ 1.1897 x 10 ^-3 C ₇ -2.2095 x 10 ^-5 C ₉ -2.8941 x 10 ^-4 C ₁₀ -4.0904 x 10 ^-6 FFS C ₄ -3.6419 x 10 ^-3 C ₅ -4.0 108 x 10 ^-5 C ₆ -3.2596 x 10 ^-3 C ₇ -8.5024 x 10 ^-6 C ₈ 9.6344 x 10 ^-7 C ₉ 1.0897 x 10 ^-5 C ₁₀ 7.0846 × 10 ^-6 C ₁₁ 1.9849 × 10 ^-7 C ₁₂ -6.9036 × 10 ^-7 C ₁₃ 1.1972 × 10 ^-6 C ₁₄ 2.7183 × 10 ^-7 C ₁₅ 6.6353 × 10 ^-8 FFS C ₄ 3.0296 × 10 ^-3 C ₅ 6.0 925 x 10 ^-4 C ₆ 2.49 68 x 10 ^-3 C ₇ -7.6 108 x 10 ^-6 C ₈ -1.4515 x 10 ^-5 C ₉ 1.7 190 x 10 ^-5 C ₁₀ -9.6 467 x 10 ^-6 C ₁₁ 1.1763 x 10 ^-7 C ₁₂ 4.8445 × 10 ^-9 C ₁₃ 5.8332 × 10 ^-7 C ₁₄ 5.7569 × 10 ^-7 C ₁₅ 1.5561 × 10 ^-7 FFS C ₄ -2.2921 × 10 ^-3 C ₅ 3.3906 × 10 ^-3 C ₆ -2.1936 x 10 ^-3 C ₇ -2.6289 x 10 ^-5 C ₈ -5.1374 x 10 ^-5 C ₉ 6.80 19 x 10 ^-5 C ₁₀ -4.1738 x 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z -1200.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 19.76 α 22.50 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -13.91 Z 5.85 α 67.50 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 10.64 Z 5.85 α 90.00 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 11.64 Z 5.85 α 90.00 β 0.00 γ 45.00 Eccentricity (6) X 0.00 Y 15.33 Z 5.85 α 90.00 β 0.00 γ 45.00 Eccentricity (7) X 0.00 Y 41.98 Z 5.85 α 73.67 β- 15.70 γ 42.73 eccentric (8) X -10.07 Y 27.74 Z -4.22 α 30.36 β -40.79 γ 20.94 eccentric (9) X 7.68 Y 27.74 Z 13.53 α 0.00 β -45.00 γ 0.00 eccentric (10) X 19.02 Y 27.74 Z 24.87 α 0.00 β -45.00 γ -45.00.

Next, FIG. 12 shows a lateral aberration diagram for Example 1 above. In this lateral aberration diagram, the numbers in parentheses represent (horizontal (X direction) angle of view, vertical (Y direction) angle of view), and the lateral aberration at that angle of view.

In the above embodiments, the powers of the entire optical system in the X and Y directions are PX and PY, respectively, and the powers of the first decentering prism 10 in the X and Y directions are Px1, Py1 and the second decentering prism, respectively. 20 or the power of the coaxial refractive optical system is Px2 and Py2. The power of each decentered prism is calculated in a coordinate system in which the direction in the plane of the decentered prism including the projection optical axis 7 is Y.

In the projection optical system 2 of the present invention, it is desirable that 0 <Px / Py <2 (1) is satisfied, and more preferably 0.5 <Px / Py <1.5.
It is preferable that (1-1) is satisfied, and more preferably 0.9 <Px / Py <1.1.
It is preferable that (1-1) is satisfied.

The lower limit of each conditional expression is 0, 0.5 or 0.
If it exceeds 9, the power in the X direction becomes weak, the image is enlarged in the X direction to a small extent, and distortion is largely generated. On the other hand, when the upper limit of 2, 1.5 or 1.1 is exceeded, the power in the Y direction becomes weak, the image is enlarged in the Y direction, and the distortion is increased.

The values of Px / Py in the above Examples 1 to 6 are as follows:
And the values of Px2 / Px1 and Py2 / Py1 are shown. Example 1 2 3 4 5 6 Px / Py 0.983 0.993 0.933 0.983 0.979 0.990 Px2 / Px1 0.127 0.067 0.011 0.140 0.805 0.810 Py2 / Py1 0.064 0.067 0.160 0.422 0.239 0.248.

In Examples 4 to 6 described above, the transparent material forming the first decentering prism 10 and the transparent material forming the second decentering prism 20 are different types, and the refracting surface of each decentering prism is different. Chromatic aberration due to dispersion at
Especially, the chromatic aberration of magnification is well corrected.

The projection optical apparatus of the present invention described above can be configured as follows, for example.

[1] A projection optical apparatus including a reflective display element, a projection optical system for projecting an image displayed on the reflective display element, and an illumination light source for illuminating the display surface of the reflective display element. In, at least the projection optical system,
The reflective display includes two or more reflective surfaces, at least one of which has a curved surface shape for giving power to a light beam and which is a rotationally asymmetric curved reflective surface having a function of correcting eccentric aberration. A catadioptric element having a positive power or a catoptric element arranged facing the display surface of the element, and a light ray that exits from the display surface and reaches the projection display surface; The light ray reaching the surface is arranged such that the illumination light source is arranged so as to reflect at least the second reflecting surface counted from the display surface side of the catadioptric optical element or the reflecting optical element in the order in which the projection light ray passes, Further, a light ray in the illumination light flux from the illumination light source that reaches the center of the display surface and has a central ray of the illumination light flux as an illumination light optical axis, and exits from the display surface center and passes through the pupil center to reach the projection display surface. Ray of light projected onto the optical axis In this case, the optical axis of illumination light incident on the catadioptric optical element or the catoptric optical element is not included in the plane passing through the optical axis of the projection light emitted from the catadioptric optical element or the catoptric optical element and the center of the display surface. A projection optical device, wherein the illumination light source is arranged as described above.

[2] Projection optical apparatus including a reflective display element, a projection optical system for projecting an image displayed on the reflective display element, and an illumination light source for illuminating the display surface of the reflective display element. In the above, the reflective display element is turned on / off by changing the inclination of micro mirrors of a large number of pixels arranged two-dimensionally to change the emission angle of reflected light.
The projection optical system includes at least two reflective surfaces, at least one of which has a curved surface shape for giving power to a light beam, and eccentric aberration correction. A rotationally asymmetric curved reflective surface having a function, and having a catadioptric optical element or a reflective optical element having a positive power and arranged facing the display surface of the reflective display element, wherein the display surface From the illumination light source to the display surface, at least the first in the order of projection light rays from the display surface side of the catadioptric optical element or reflective optical element. The illumination light source is arranged so as to reflect the reflection surface together, and the light ray reaching the center of the display surface in the illumination light flux from the illumination light source and the central light ray of the illumination light flux as the illumination light optical axis , The above When the ray that exits the center of the plane of view and passes through the center of the pupil and reaches the projection display surface is the projection optical axis, the illumination optical axis that enters the catadioptric optical element or catadioptric optical element is the catadioptric optical element or the catoptric optical element. A projection optical device, wherein the illumination light source is arranged so as not to be included in a plane passing through an optical axis of a projection light emitted from an optical element and the center of the display surface.

[3] The catadioptric optical element or catadioptric element is composed of a first decentered prism having two reflecting surfaces, and is reflected by the reflecting surface that emerges from the display surface and the projection optical axis first enters. When the projection light optical axis reflected by the second reflecting surface is projected onto a plane including the projected projection light optical axis and the projection light optical axis incident on the reflecting surface, the second reflecting surface reflects the light. 3. The first decentering prism is configured so that the image of the projected optical axis of the projected light intersects the optical axis of the projected light reflected by the first incident reflecting surface. Projection optics.

[4] The projection optical device according to the above item 3, wherein the projection optical system includes another optical system on the side where the projection light beam exits from the first decentering prism.

[5] The other optical system is at least
A second decentering prism having one or more reflecting surfaces, the reflecting surface having a curved surface shape for giving power to a light beam, and comprising a rotationally asymmetric curved reflecting surface having a decentering aberration correction function. 5. The projection optical device according to 4 above.

[6] In each of the first decentering prism and the second decentering prism, the projection optical axis in the prism is included in a plane, and the plane in the first decentering prism and the second decentering prism are included. 6. The projection optical device according to the above 5, wherein the plane in the decentering prism is parallel to the plane.

[7] In each of the first decentering prism and the second decentering prism, the projection optical axis in the prism is included in a plane, and the plane in the first decentering prism and the second decentering prism are included. The plane in the decentered prism is mutually 45
6. The projection optical device according to the above 5, wherein the projection optical device is rotated by °.

[8] The second decentering prism is provided with two reflecting surfaces, and the projection optical axes intersect each other in the plane of the second decentering prism. 6. The projection optical device according to 6 or 7 above.

[0106]

[9] The projection optical device according to the above item 6 or 7, wherein the second decentering prism has one reflecting surface.

[10] The reflection type display element is formed of a reflection type liquid crystal display element.
The projection optical device according to claim 1.

[11] The reflection type display element is a reflection type which makes an on / off state by changing the inclination of micromirrors of a large number of pixels arranged two-dimensionally to change the emission angle of reflected light. 6 to 9, wherein the reflection type display element is formed of a display element, and the reflection type display element is arranged so that the deflection direction of the reflected light by the micro mirror is orthogonal to the plane in the first decentering prism. One of
The projection optical device according to the item.

[12] The transparent medium forming the first decentering prism and the transparent medium forming the second decentering prism have different optical properties from each other.
The projection optical device according to claim 1.

[0110]

As described above, according to the present invention, the decentering prism is used as the projection optical system, and the projection optical system is downsized by devising the way of introducing the illumination light into the reflection type display element. A device can be provided. The present invention is
In particular, it is suitable for a projection optical device that uses a DMD as a display element.

[Brief description of drawings]

FIG. 1 is a perspective view of a projection optical system according to a first exemplary embodiment of the present invention as viewed obliquely from above on a projection display surface side.

FIG. 2 is a perspective view of the first embodiment seen from the same direction as FIG.

3 is a front perspective view of the first embodiment viewed from the front side of FIGS. 1 and 2. FIG.

4 is a YZ sectional view of the projection optical system of Example 1. FIG.

5 is a schematic perspective view of an entire apparatus using the projection optical system of Example 1. FIG.

6 is a YZ sectional view of the projection optical system of Example 2. FIG.

FIG. 7 is a schematic perspective view of an entire apparatus using the projection optical system of Example 2.

FIG. 8 is a YZ sectional view of the projection optical system of Example 3;

FIG. 9 is a schematic perspective view of an entire apparatus using the projection optical system of Example 3.

FIG. 10 is a schematic perspective view of the entire apparatus using the projection optical system of Example 4.

FIG. 11 is a schematic perspective view of an entire apparatus using the projection optical system of Examples 5 and 6.

FIG. 12 is a diagram showing transverse aberration of the first example.

[Explanation of symbols]

1-Reflective display device (DMD, reflective liquid crystal display device) 2 ... Projection optical system 3 ... Illumination light source 4 ... Aperture 5 ... Projection display surface 6 ... Illumination optical axis 7 ... Projection optical axis 10 ... First decentered prism 11 ... Incident surface 12 ... 1st reflective surface 13 ... Second reflective surface 14 ... Ejection surface 20 ... Second decentered prism 21 ... Incident surface 22 ... Reflective surface (first reflective surface) 23 ... Ejection surface (second reflection surface) 24 ... Ejection surface 30 ... Illumination light introducing prism

Claims (3)

[Claims] 1. A projection optical apparatus comprising a reflective display element, a projection optical system for projecting an image displayed on the reflective display element, and an illumination light source for illuminating a display surface of the reflective display element. The projection optical system includes at least two reflecting surfaces, at least one of which has a curved surface shape for giving power to a light beam, and a rotationally asymmetric curved reflecting surface having a decentering aberration correcting function. And having a catadioptric optical element or a catadioptric optical element having a positive power arranged facing the display surface of the reflective display element, and a light ray coming out of the display surface to the projection display surface. The light rays emitted from the illumination light source and reaching the display surface are reflected together by at least the second reflection surface counted from the display surface side of the catadioptric optical element or the reflection optical element in the order in which projection light rays pass. In front An illumination light source is arranged, and a light ray reaching the center of the display surface in the illumination light flux from the illumination light source is a central light ray of the illumination light flux as an illumination light optical axis, and exits from the display surface center and the pupil center. When the ray reaching the projection display surface is the projection light optical axis, the illumination light optical axis incident on the catadioptric optical element or the catoptric optical element is the projection light optical axis emitted from the catadioptric optical element or the catoptric optical element. The projection optical device, wherein the illumination light source is arranged so as not to be included in a plane passing through the center of the display surface. 2. A projection optical apparatus comprising a reflective display element, a projection optical system for projecting an image displayed on the reflective display element, and an illumination light source for illuminating a display surface of the reflective display element. The reflective display element is a reflective display element that creates an on / off state by changing the inclination of micromirrors of a large number of pixels arranged two-dimensionally to change the emission angle of reflected light, The projection optical system is provided with at least two reflecting surfaces, and at least one of the reflecting surfaces has a curved surface shape for giving power to a light beam, and is a rotationally asymmetric curved reflecting surface having a decentering aberration correcting function. Configured to have a catadioptric optical element or catadioptric element having a positive power disposed facing the display surface of the reflective display element, and a ray of light from the display surface to the projection display surface, The lighting The light ray emitted from the light source and reaching the display surface is the illumination light source so that at least the first reflection surface is counted together in the order in which the projection light ray passes from the display surface side of the catadioptric optical element or the reflection optical element. And a central ray of the illumination light flux, which is a light ray in the illumination light flux from the illumination light source that reaches the center of the display surface, is projected through the center of the display surface and the pupil center. When the ray reaching the display surface is the projection optical axis, the illumination optical axis incident on the catadioptric optical element or catoptric optical element is the projection optical optical axis emitted from the catadioptric optical element or catoptric optical element and the display. A projection optical device in which the illumination light source is arranged so as not to be included in a plane passing through a plane center. 3. The catadioptric optical element or the catadioptric optical element comprises a first decentered prism having two reflecting surfaces, which is reflected by a reflecting surface that emerges from the display surface and on which a projection optical axis first enters. When the projection light optical axis reflected by the second reflecting surface is projected on the plane including the projection light optical axis and the projection light optical axis incident on the reflecting surface, the light is reflected by the second reflecting surface. The first decentering prism is configured such that the image of the projected light optical axis intersects with the projected light optical axis reflected by the first incident reflecting surface in the prism. Or the projection optical device according to item 2.