JP2001235681A - Back projection display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a back projection display device which is made thin and compact while holding an excellent optical performance. SOLUTION: This device is provided with a projection optical system by which the picture of a panel display surface is obliquely projected on a screen surface 12 and which is axially asymmetric and plane mirror system M1 and M2 to bend an optical path from the projection optical system to the screen surface 12, and the projection optical system has at least one free bent surface reflection surface. A luminous flux from the projection optical system is reflected by the plane reflection surface of the second mirror M2, and reaches the screen surface 12 by crossing the optical path from the projection optical system to the plane reflection surface of the second mirror M2 after being reflected by the plane reflection surface of the first mirror M1 opposed to the screen surface 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear projection display device, and more particularly, to a projection optical system for projecting an image on a panel display surface onto a screen surface, and an optical path from the projection optical system to the screen surface. And a flat mirror system for bending the rear projection display device.

[0002]

2. Description of the Related Art In a general rear projection display device, the thickness of the light is reduced by folding an optical path of light emitted from a projection optical system by a single reflecting mirror behind the screen. However, since the projection optical system used is a coaxial system,
Light rays incident on the center of the screen surface must be substantially perpendicular to the screen surface. This makes it difficult to make the rear projection display device thinner than a certain thickness. In order to solve this problem, a rear projection display device for obliquely projecting an image on a screen surface is disclosed in Japanese Patent Laid-Open No. 2-96.
737, JP-A-5-165095, JP-A-5-40311, JP-A-5-27326,
JP-A-5-158151, JP-A-5-16509
No. 6, WO97 / 01787 and the like.

[0003]

However, in the optical configuration of the conventional rear projection display device as described above, it is difficult to achieve a sufficient thickness reduction, and new optical characteristics such as deterioration of optical performance accompanying the reduction in thickness are required. Or problems.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a rear projection display device which achieves thinness and compactness while maintaining good optical performance.

[0005]

According to a first aspect of the present invention, there is provided a rear projection display apparatus comprising: a non-axially symmetric projection optical system for obliquely projecting an image on a panel display surface onto a screen surface; A flat mirror system that bends an optical path from the projection optical system to the screen surface, wherein the projection optical system has at least one free-form surface reflecting surface, and the flat mirror system has A first plane reflection surface facing the screen surface and a second plane reflection surface, and a light beam emitted from the projection optical system is reflected by the second plane reflection surface. The projection optical system and the plane mirror system so that the light is reflected and further reflected by the first plane reflection surface, and then reaches the screen surface across an optical path from the projection optical system to the second plane reflection surface. Is placed And said that you are.

A rear projection display apparatus according to a second aspect of the present invention is the rear projection display apparatus according to the first aspect, wherein a light ray reaching the screen center of the screen surface from the center of the screen of the panel display surface through the center of the stop is used as a center ray of the screen. When a light ray from the outermost periphery of the screen on the panel display surface and reaching the outermost periphery of the screen on the screen surface through the center of the stop is defined as a peripheral light of the screen, the following conditional expression is satisfied. S1> D / cosαu + D · (tanαl−tanαu) + HD> 2 · E · tan {(αl−αu) / 2} where αu = tan ⁻¹ {(S1 · sinα−H / 2) / (S1 · cosα )} αl = tan ⁻¹ {(S1 · sinα + H / 2) / (S1 · cosα)} E = 0.8 · (S1−1.5 · D / cosα) S1: Exit pupil position of projection optical system or final of projection optical system The optical distance of the central ray of the screen from the surface to the screen surface, D: the component of the optical distance of the central ray of the screen from the first plane reflecting surface to the screen surface, perpendicular to the screen surface, H: the normal to the screen surface The size of the screen surface in the direction parallel to the plane defined by the screen and the center ray of the screen, α: the angle of incidence of the center ray of the screen with respect to the screen surface, αu: the screen peripheral ray of light reaching the center of the upper side of the screen with respect to the screen surface Incident angle, αl: The screen marginal rays that reach the center of the lower side of the screen on the screen The angle of incidence with respect to the

According to a third aspect of the present invention, there is provided a rear projection display apparatus, wherein a non-axially symmetric projection optical system for obliquely projecting an image on a panel display surface onto a screen surface, and a plane for bending an optical path from the projection optical system to the screen surface. A mirror system, wherein the projection optical system has at least one free-form surface reflection surface, and the plane mirror system has a first plane reflection surface facing the screen surface; A second plane reflecting surface positioned substantially parallel to the screen surface and near the screen surface; and a luminous flux emitted from the projection optical system is reflected by the second plane reflecting surface. The projection optical system and the plane mirror system are arranged so that the light is reflected and further reflected on the first plane reflection surface, and then reaches the screen surface. When the light beam reaches the screen center of the street the screen surface mind as the screen central ray, and satisfies the following conditional expression. α> 45 ° D <H / 2, where α is the angle of incidence of the center ray of the screen with respect to the screen plane, and D is the direction perpendicular to the screen plane at the optical distance of the center ray of the screen from the first plane reflecting surface to the screen plane. H: the size of the screen surface in a direction parallel to the plane formed by the normal line of the screen surface and the center ray of the screen.

A rear projection display apparatus according to a fourth aspect of the present invention is the rear projection display apparatus according to the third aspect of the present invention, wherein light rays reaching the outermost periphery of the screen on the screen surface from the outermost periphery of the panel display surface through the center of the aperture are displayed on the screen. When the marginal ray is used, the following conditional expression is further satisfied. S1> 2 · D / cosα 2 · D · tanαl> H where α1 = tan ^-1 {(S1 · sinα + H / 2) / (S1 · cosα)} α1: A peripheral light ray reaching the center of the lower side of the screen on the screen surface S1: the exit pupil position of the projection optical system or the optical distance of the center ray of the screen from the final surface of the projection optical system to the screen surface.

According to a fifth aspect of the present invention, there is provided a rear projection display apparatus comprising: a non-axisymmetric projection optical system for obliquely projecting an image on a panel display surface onto a screen surface; and a plane for bending an optical path from the projection optical system to the screen surface. A mirror system, wherein the projection optical system has at least one free-form surface reflection surface, and the plane mirror system has a first plane reflection surface facing the screen surface; A second plane reflecting surface, and at least two plane reflecting surfaces, wherein a light beam emitted from the projection optical system is reflected by the first plane reflecting surface, and further reflected by the second plane reflecting surface. Thereafter, the projection optical system and the plane mirror system are arranged so as to reach the screen surface.

A rear projection display apparatus according to a sixth aspect of the present invention is the rear projection display apparatus according to the fifth aspect, wherein a ray reaching the center of the screen on the screen surface from the center of the screen of the panel display surface through the center of the stop is a center ray of the screen. When a light ray from the outermost periphery of the screen on the panel display surface and reaching the outermost periphery of the screen on the screen surface through the center of the stop is defined as a peripheral light of the screen, the following conditional expression is satisfied. S1> D / cosα D · tanαl> H where α1 = tan ⁻¹ {(S1 · sinα + H / 2) / (S1 · cosα)} S1: From the exit pupil position of the projection optical system or the final surface of the projection optical system, the screen D: the optical distance of the center ray of the screen from the first plane reflecting surface to the screen surface, the component perpendicular to the screen plane in the optical distance of the center ray of the screen from the first plane reflecting surface to the surface; The size of the screen surface in the direction parallel to the plane formed by the light rays, α: the incident angle of the screen center ray to the screen surface, αl: the incident angle of the screen peripheral rays reaching the center of the lower side of the screen surface to the screen surface, It is.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rear projection display device embodying the present invention will be described below with reference to the drawings. The rear projection display device according to each of the embodiments includes types 1 to 3 and modified types 1 ′ to 3 ′ based on the characteristic arrangement of the plane mirror system (MS).
It can be broadly divided into FIGS. 1 to 8 show an optical configuration and a projection optical path of type 1, and FIGS. 9 and 10 show an optical configuration and a projection optical path of type 1 ′ which is a modification of type 1.
FIGS. 11 to 16 show an optical configuration and a projection optical path of type 2, and FIGS. 17 and 18 show an optical configuration and a projection optical path of type 2 ′ which is a modification of type 2. FIGS. 19 to 23 show an optical configuration and a projection optical path of type 3, and FIG. 24 shows an optical configuration and a projection optical path of type 3 ′ which is a modification of type 3.

The optical cross-sections shown in the optical path diagrams of FIGS. 1 to 24 have a YZ cross-sectional configuration in a rectangular coordinate system (X, Y, Z), which will be described later. It is not limited to the one shown in the optical path diagram, but may be upside down. That is, there is no problem even if the upper side in each optical path diagram is set to the lower side in accordance with the actual arrangement. Note that the Y direction is a direction parallel to the screen surface (I2) (upward in the drawing is positive), and the Z direction is a normal direction to the screen surface (I2) (the right direction in the drawing is positive). And.). Also, the center point O (FIGS. 1, 9, 11, 17, and 19) of the screen surface is the Y axis, Z
It is the origin of the axis, and the inclination angle of the surface counterclockwise toward the paper surface is positive.

In any type of rear projection display device, the image display surface of the display panel is a panel display surface (I1; see each embodiment described later) on the reduction side, and the panel display surface (I1).
And a non-axisymmetric projection optical system (PS) for obliquely enlarging and projecting the two-dimensional image on the screen surface (I2). This projection optical system (PS) may be a reflection type optical system consisting of only a reflection surface,
A catadioptric optical system composed of a combination of a reflecting surface and a refracting surface may be used, but it is preferable that the reflecting surface has at least one free-form reflecting surface. The free-form surface reflection surface is introduced into the projection optical system (PS), for example, as a reflection surface of a free-form surface reflection mirror.

The free-form surface constituting the reflection surface is a surface that includes a large eccentric aspheric surface and does not have a rotationally symmetric axis near the center of the effective area. Degree of freedom). If the curvature of the reflecting surface is controlled three-dimensionally using the aspherical undulation of the free-form surface, non-axially symmetric aberrations (distortion etc.) due to oblique projection can be obtained by the inclination of the surface set for each location of the reflecting surface. ) Can be easily corrected. The free-form surface does not have an axis of rotational symmetry, but desirably has one plane of symmetry. In each embodiment, the YZ plane (a plane parallel to the paper of each optical path diagram) is a symmetric surface of each free-form surface, and each curved surface reflection mirror has a free-form surface that is plane-symmetric with respect to the symmetric surface as a reflection surface. ing. Such a plane-symmetric free-form surface has
There is an advantage that the difficulty in manufacturing and evaluation is lower than in the case of not being plane-symmetric.

Each type of rear projection display device includes a plane mirror system (MS) that bends the optical path from the projection optical system (PS) to the screen surface (I2). First to third mirrors (M1, M2, M3) constituting this plane mirror system (MS)
Have a plane reflecting surface, of which the plane reflecting surface of the first mirror (M1) faces the screen surface (I2). In the rear projection display device according to the present invention, the plane mirror system
Regardless of which type is used for (MS), the first and second
At least two plane reflecting surfaces including the plane reflecting surfaces of the mirrors (M1, M2) are used.

The display panel includes a reflection type liquid crystal panel, a transmission type liquid crystal panel, and a DMD (Digital Micromirror).
Device) is used, and the panel display surface (I
1) is illuminated with illumination light emitted from a light source (not shown) such as a lamp and then passing through an illumination optical system (not shown).
The projection light emitted from the panel display surface (I1) by the illumination is guided to the screen surface (I2) by the projection optical system (PS), the plane mirror system (MS), and the like.

<< Type 1 >> FIG. 1 shows a basic optical configuration of a type 1 plane mirror system (MS). 2 to 8
The projection optical paths from the projection optical system (PS) to the screen surface (I2) in the first to seventh embodiments of the type 1 are shown below. Type 1 projection optical system (PS) and plane mirror system (M
In the arrangement of (S), the light beam emitted from the projection optical system (PS) is reflected by the plane reflecting surface of the second mirror (M2), and is further reflected by the first mirror.
After being reflected by the plane reflection surface of (M1), the light reaches the screen surface (I2) across the optical path from the projection optical system (PS) to the plane reflection surface of the second mirror (M2). At this time, since the projection optical system (PS) that performs oblique projection is configured to be non-axially symmetric, it is possible to reduce the thickness of the rear projection display device. In addition, projection optical system (PS)
Uses a free-form reflecting surface, so that image performance can be improved. In the arrangement of the type 1 plane mirror system (MS), the light beam reflected by the plane reflecting surface of the first mirror (M1) is the same as the light beam from the projection optical system (PS) to the second mirror (M2). The configuration is not limited to the case where the optical paths intersect on a plane.

In order to ensure the optical performance of the projection optical system (PS), it is preferable to reduce the projection angle of view, and for that purpose, it is necessary to increase the projection distance. By using at least two plane reflecting mirrors (M1, M2) to efficiently bend the optical path from the projection optical system (PS) to the screen surface (I2), a long projection distance can be ensured, and the display device Can be made thin and compact. In order to achieve efficient bending of the optical path, it is desirable to satisfy the following conditional expressions (i) and (ii). However, a ray that reaches the center of the screen on the screen surface (I2) from the center of the screen on the panel display surface (I1) through the center of the aperture stop (ST; see each embodiment described later) is referred to as “screen center ray”. Aperture (ST) from the outermost edge of the screen (I1)
A ray that reaches the outermost edge of the screen on the screen surface (I2) through the center of the screen is referred to as a “screen peripheral ray”. In addition to using a projection optical system (PS) including a free-form reflecting surface, the following conditional expressions (i) and (i)
By adopting an optical arrangement that satisfies i), it is possible to achieve a thin and compact rear projection display device.

S1> D / cosαu + D · (tanαl−tanαu) + H (i) D> 2 · E · tan {(αl−αu) / 2} (ii) where αu = tan ⁻¹ {(S1 · sinα−H / 2) / (S1 · cosα)} αl = tan ⁻¹ {(S1 · sinα + H / 2) / (S1 · cosα)} E = 0.8 · (S1−1.5 · D / cosα) S1: Projection optics Exit pupil position of system (PS) or projection optical system (PS)
The optical distance of the central ray of the screen from the last surface of the first mirror to the screen surface (I2), D: from the plane reflecting surface of the first mirror (M1) to the screen surface (I2)
Screen plane at the optical distance of the screen center ray to
H: A component in the vertical direction (that is, horizontal direction) with respect to (I2). H: With respect to a plane (corresponding to the YZ plane in each optical path diagram) formed by the normal to the screen surface (I2) and the screen center ray. The size of the screen surface (I2) in the parallel direction (corresponding to the length of the short side in each embodiment), α: the incident angle of the screen center ray with respect to the screen surface (I2), αu: the screen surface (I2) Αl is an incident angle of a screen peripheral ray reaching the center of the lower side of the screen surface (I2) with respect to the screen surface (I2) of the screen peripheral ray reaching the center of the upper side of the screen.

The above conditional expressions (i) and (ii) will be described in more detail. Type 1 is a compact rear projection display
In order to obtain an optimal optical configuration layout (especially for thinning), a first mirror (M1) substantially parallel to the screen surface (I2) and an inclination of 90 ° or less with respect to the first mirror (M1) are required. The optical path is bent by two mirrors (M1 and M2) having another second mirror (M2). The reason why the two plane reflecting mirrors (M1, M2) are used is to increase the distance S1 to reduce the projection angle of view on the screen surface (I2) and to easily secure image performance.
If the distance S1 is too short, the layout becomes impossible because the projection optical system (PS) interferes with the optical path. Therefore, the condition of the distance S1 (= the length of OC ') required to bend the optical path is determined.

For the sake of simplicity, it is assumed that the first mirror (M1) is arranged parallel to the screen surface (I2) (actually, it need not be parallel, and that case will be described later as a modification. ), And the relationship of D <H holds because of the thinness. This distance D corresponds to the thickness of the rear projection optical system including the projection optical system (PS) and the plane mirror system (MS), and the size H is the screen vertical direction on the screen surface (I2).
(Y direction). Also, here, the distance S1 is the optical distance of the screen center ray from the exit pupil position of the projection optical system (PS) to the screen surface (I2). Since the distances are substantially equal, the distance S1 may be read as the optical distance of the center ray of the screen from the final surface of the projection optical system (PS) to the screen surface (I2). For the distance S1, the length required in principle will be considered.

When H, D, α, and S1 are determined to be certain values, the sizes of the incident angles αu and αl are determined. When the point Au is determined, the minimum height of the point Bu in the Y direction (= Y direction of the point Au) Height) is determined. Here, point A is the intersection of the screen center ray and the first mirror (M1), and point Au is the intersection of the screen peripheral ray reaching the center of the upper side of the screen on the screen surface (I2) and the first mirror (M1). The point Al is the intersection of the screen peripheral ray reaching the center of the lower side of the screen on the screen surface (I2) and the first mirror (M1). Point B is the intersection of the screen center ray and the second mirror (M2), and point Bu is the intersection of the screen peripheral ray reaching the center of the upper surface of the screen surface (I2) and the second mirror (M2). Yes, point B
l is the intersection of the screen peripheral ray reaching the center of the lower side of the screen on the screen surface (I2) and the second mirror (M2).

Assuming that the Y components of the points Au and Bu are represented by AuY and BuY, respectively, in order to prevent the first mirror (M1) and the second mirror (M2) from interfering with each other, the following conditional expression (1) Should be satisfied. In order to prevent the second mirror (M2) from protruding toward the observer from the screen surface (I2), the following conditional expression is used.
It is sufficient to satisfy (2). Furthermore, the screen surface (I2) and the second
In order to prevent interference with the mirror (M2), the following conditional expression (3) may be satisfied. Considering that the center ray of the screen is incident on the position of the point B, as the thickness D is reduced,
The position of the point B in the Z direction is approximately half the thickness. Therefore, the following equation (4) holds. BuY> AuY (1) BlZ> 0.0 (2) BlY> H / 2 (3) BZ ≒ D / 2 (4)

When the thickness of the rear projection display device is reduced, the incident angle α increases and the inclination angle b of the second mirror (M2) decreases. In order to maximize the space efficiency, any one of the light rays from the point between Bu to B to Bl on the reflecting surface of the second mirror (M2) to the point C is applied to the method of the screen surface (I2). Preferably, it is perpendicular to the line (ie parallel to the screen plane (I2)). Furthermore, in order to minimize the distance S1, the light beam BuC is applied to the screen surface (I2).
Ideally, it should be perpendicular to the normal of In such a configuration, the inclination angle b is expressed by the following equation (5). b = (90 ° -αu) / 2 (5)

From the condition that the screen surface (I2) is parallel to the first mirror (M1) and the condition (3), the following condition (6) is satisfied. Also, from the relationship 0 ° <α (or αu) <90 ° and the condition (5), the relationship 0 ° <b <45 ° holds, so that interference between the light beam and the second mirror (M2) is eliminated. Needs to satisfy the following conditional expression (7). AlZ> 0.0… (6) αu> 0 °… (7)

Further, from conditional expressions (6) and (7), OA> OuAu
Holds, and similarly, AB + BC> AuBu + Bu
Since the relationship of C holds, the condition that the distance S1 needs to satisfy at least is expressed by the formula: S1> OuAu + AuBu + BuC. Here, AuBu is 0.0 at the shortest, and BuC is AuAl at the shortest. Therefore, the conditional expression (i) is obtained from the following expressions (8a) and (8b). AuAu = D / cosαu (8a) AuAl = D · (tanαu-tanαl) + H (8b) S1> D / cosαu + D · (tanαl-tanαu) + H (i) where αu = tan ⁻¹ {(S1 · sinα−H / 2) / (S1 · cosα)} α1 = tan ⁻¹ {(S1 · sinα + H / 2) / (S1 · cosα)}

If the distance S1 does not satisfy the conditional expression (i), it becomes impossible in principle to form a type 1 optical configuration.
If the distance S1 is too long, the optical path may protrude downward. A slightly longer length can be dealt with by bending the optical path in a direction perpendicular to the paper surface. For example, if a third mirror (M3) for bending the optical path in the horizontal direction (perpendicular to the paper) is newly provided between the final surface of the projection optical system (PS) and the second mirror (M2), the rear projection display Upper or lower part of the device {that is, the part where the display panel and the projection optical system (PS) are arranged}
Bulge can be reduced. At this time, since the folding is performed by the plane reflection mirror, the optical symmetry is not broken.

However, if the distance S1 is longer than necessary, the compactness of the display device is impaired. Also, H,
If the distance S1 is too long with respect to the various values of D and α, the light beam width on the second mirror (M2) becomes large and exceeds the width of D, and the optical configuration is established in principle. Will not be. This is solved by conditional expression (ii). If the distance from the second mirror (M2) to the point C is E, the equation: E = S
1- (OA + AB) holds. Since the luminous flux width (the width from the center of the upper side of the screen to the center of the lower side of the screen) needs to be smaller than D when traveling from the point C by the distance E, it is desirable to satisfy the conditional expression (ii). Here, it is more desirable to set E = 0.8 · (S1−1.5 · D / cos α) in consideration of a margin of about 20%. D> 2 · E · tan {(αl-αu) / 2} (ii)

Data shown in the upper part of the apparatus in FIGS. 2 to 8 are various values (H * D, α−) of the first to seventh embodiments.
S1) (the same applies to other embodiments described later). Table 1 below shows corresponding values of the conditional expressions (i) and (ii) obtained from these data and related data.

[0030]

[Table 1]

<< Type 1 '>> In the case of Type 1, the first mirror (M1) is arranged parallel to the screen surface (I2), but may not actually be parallel as described above. .
FIG. 9 shows a basic optical configuration in that case. In this type 1 ′, the first mirror (M1) is tilted counterclockwise at a slight angle a (a> 90 °), but the first mirror (M1) is substantially parallel to the screen surface (I2). To the extent that it is considered to be located, it is possible to apply the above-described conditional expressions (i) and (ii) of type 1 and the description related thereto to type 1 ′ as well. As an example of this type 1 ', an eighth embodiment is shown in FIG. In the eighth embodiment, the first mirror (M
The plane reflecting surface of 1) is located at a position rotated counterclockwise by 5 ° from the arrangement parallel to the screen surface (I2). Table 2 below shows corresponding values of conditional expressions (i) and (ii) and related data of the eighth embodiment.

[0032]

[Table 2]

<< Type 2 >> FIG. 11 shows a basic optical configuration of a type 2 plane mirror system (MS). 12 to 16 show the projection optical paths from the projection optical system (PS) to the screen surface (I2) in the ninth to thirteenth embodiments of type 2, respectively. In the arrangement of the projection optical system (PS) and the plane mirror system (MS) of type 2, the plane reflection surface of the second mirror (M2) is
It is located near the screen surface (I2) substantially parallel to the screen surface (I2). Then, the light beam emitted from the projection optical system (PS) is reflected on the plane reflecting surface of the second mirror (M2), and further reflected on the plane reflecting surface of the first mirror (M1), and then is reflected on the screen surface (I2). To reach. At this time, a projection optical system that performs oblique projection
Since the (PS) is configured to be non-axially symmetric, the thickness of the rear projection display device can be reduced. Further, since a free-form reflecting surface is used in the projection optical system (PS), the image performance can be improved.

As can be said for all types described in this specification, it is desirable to satisfy the following conditional expression (iv) in order to meet the demand for a thin rear projection display device. If this conditional expression (iv) is satisfied, the incident angle α must be large, so that it is desirable to satisfy the following conditional expression (iii) in order to achieve a thin and compact rear projection display device. . Therefore, the following conditional expression (iii),
It is even more desirable that both of the conditions (iv) be satisfied. Especially type 2
In the optical configuration of (2), since the plane reflecting surface of the second mirror (M2) is arranged near the screen surface (I2) and substantially parallel to the screen surface (I2), the conditional expressions (iii) and (iv) are satisfied. There is an advantage that a configuration that satisfies both can be easily obtained. α> 45 °… (iii) D <H / 2… (iv)

The condition required for the distance S1 in the type 2 is represented by the formula: S1> OA + AB = 2 · OA, so that the following conditional expression (v) is obtained. In addition, the second mirror (M
The light rays at the center of the lower side of the screen in 2) are the screen surface (I2)
In order not to interfere with the condition, the following conditional expression (vi) may be satisfied. Therefore, in the type 2 optical configuration, it is desirable to satisfy the following conditional expressions (v) and (vi).
By using a projection optical system (PS) that includes a free-form reflecting surface and by using an optical arrangement that satisfies the following conditional expressions (v) and (vi), it is possible to achieve a thin and compact rear projection display device. Can be. S1> 2 · D / cosα (v) 2D · tanαl> H (vi)

Table 3 below shows corresponding values of conditional expressions (v) and (vi) of the ninth to thirteenth embodiments of the type 2 (FIGS. 12 to 16) and related data. In the thirteenth embodiment (FIG. 16), the plane mirror system (MS) is composed of three plane reflection mirrors (M1, M2, M3).

[0037]

[Table 3]

<< Type 2 '>> In the case of Type 2, the first
Although the second mirrors (M1, M2) are both arranged parallel to the screen surface (I2), one or both of them may not actually be parallel. FIG. 1 shows the basic optical configuration in that case.
FIG. In this type 2 ', the first and second mirrors (M1, M
2) Both are tilted clockwise at a slight angle a, b
(a, b <90 °), as long as the mirrors (M1, M2) are considered to be positioned substantially parallel to the screen surface (I2), the conditional expressions (iii) to (vi) of the type 2 described above. ) And its related description can be applied to type 2 'as well. When the plane reflecting mirrors (M1, M2) are tilted in this way, there is an advantage that the degree of freedom in layout is increased. As an example of this type 2 ', the fourteenth embodiment is shown in FIG.
Shown in In the fourteenth embodiment, the plane reflecting surface of the first mirror (M1) is shifted from the arrangement parallel to the screen surface (I2) by 5%.
It is in the position rotated clockwise by °. Table 4 below shows corresponding values of conditional expressions (v) and (vi) of the fourteenth embodiment and related data.

[0039]

[Table 4]

<< Type 3 >> FIG. 19 shows a basic optical configuration of a type 3 plane mirror system (MS). 20 to 23 show projection optical paths from the projection optical system (PS) to the screen surface (I2) in the fifteenth to eighteenth embodiments of type 3, respectively. In the arrangement of the type 3 projection optical system (PS) and the plane mirror system (MS), the light beam emitted from the projection optical system (PS) is reflected by the plane reflection surface of the first mirror (M1), and further, the second mirror After being reflected by the plane reflecting surface of (M2), it reaches the screen surface (I2). At this time, a projection optical system that performs oblique projection
Since the (PS) is configured to be non-axially symmetric, the thickness of the rear projection display device can be reduced. Further, since a free-form reflecting surface is used in the projection optical system (PS), the image performance can be improved.

Assuming that the screen surface (I2) and the second mirror (M2) are perpendicular and the screen (I2) and the first mirror (M1) are parallel, the type 3 requires the distance S1. The condition is represented by the formula: S1> OA + AB. Therefore, the following conditional expression (vii) is obtained. In order to prevent the screen peripheral rays at the center of the lower side of the screen from interfering between the first and second mirrors (M1, M2), the following conditional expression (viii) may be satisfied. Therefore, in the type 3 optical configuration, it is desirable to satisfy the following conditional expressions (vii ′) and (viii ′).
By using a projection optical system (PS) that includes a free-form reflecting surface and by using an optical arrangement that satisfies the following conditional expressions (vii ') and (viii'), a thin and compact rear projection display device is achieved. can do. S1−D / cosα> 0 (vii) D · tanαl−H> 0 (viii) S1> D / cosα (vii ′) D · tanαl> H (viii ′)

Fifteenth to eighteenth embodiments of type 3
Table 5 below shows corresponding values of conditional expressions (vii) and (viii) in (FIGS. 20 to 23) and related data.

[0043]

[Table 5]

<< Type 3 '>> In the case of Type 3, the second mirror (M2) is arranged perpendicular to the screen surface (I2), but it is not necessarily perpendicular. As a type 3 ′ which is a modification of the type 3, the nineteenth embodiment is shown in FIG.
It is shown in FIG. In the nineteenth embodiment, the plane reflecting surface of the second mirror (M2) is shifted from the position perpendicular to the screen surface (I2).
It is in a position rotated counterclockwise by 2.5 °. The above-mentioned conditional expressions (vii) and (viii) of type 3 and the description related thereto are similarly applied to this type 3 'as long as it is considered to be positioned substantially perpendicular to the screen surface (I2). It is possible to do. Conditional expression of the nineteenth embodiment
The corresponding values and related data of (vii) and (viii) are shown in Table 6 below.

[0045]

[Table 6]

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The optical configuration of a rear projection display device embodying the present invention will be described more specifically with reference to construction data, a spot diagram and the like. FIG. 25-
FIG. 31 shows an optical configuration and a projection optical path of Examples 1 to 7 described below. The first to fourth embodiments include, in order from the screen surface (I2) side, a plane mirror system (MS) including first and second mirrors (M1, M2) and third to fifth mirrors (m3 to m5). A projection optical system (PS), and Examples 5 to 7 include, in order from the screen surface (I2) side, a plane mirror system (MS) including first and second mirrors (M1, M2), A projection optical system (PS) including third to sixth mirrors (m3 to m6). In the fourth embodiment, a prism (PR) corresponding to a cross dichroic prism, a light beam splitting prism, and the like is arranged near the panel display surface (I1). The stop position (ST) corresponds to a virtual stop surface.

In the construction data of each embodiment, Tables 7 to 13 show a plane mirror system (MS) and a projection optical system.
The data of each surface of the rear projection optical system composed of (PS) are shown in order from the reduction side. Each plane data is shown based on the right-handed rectangular coordinate system (X, Y, Z), and the vertex coordinates of the plane (m, with the center position of the screen plane (I2) as the origin (0, 0, 0))
m) represents the surface position (X coordinate, Y coordinate, Z coordinate), and the inclination (X) of the surface with the rotation angle (°) around the axis in each of X, Y, and Z directions with the surface vertex as the center. Rotation, Y rotation, Z rotation). In the optical path diagram, the X-axis direction is a direction perpendicular to the paper surface (the back surface direction of the paper surface is defined as positive, and the counterclockwise rotation toward the paper surface is defined as X rotation positive), and the Y-axis direction is the screen surface (I2 ) And the paper surface (the upper direction of the optical path diagram is defined as positive), and the Z-axis direction is the normal direction of the screen surface (I2) (the right direction of the optical path diagram is defined as positive). .

The reflecting surface of the curved reflecting mirror is a free-form surface, and its surface shape is an orthogonal coordinate system (x, y,
It is defined by the following formula (FS) using z). Free-form surface data representing each curved surface shape, panel display surface (I1) size (mm), screen surface (I2) size (mm), screen long side direction (X direction) and screen short side direction (Y direction) ) Shows the F number (FNO) together with other data. Table 14 shows conditional expression corresponding values and related data of each embodiment.

[0049]

(Equation 1)

Here, z: displacement amount from the reference plane in the optical axis direction at the position of height h, h: height in the direction perpendicular to the optical axis (h ² = x ² + y ² ), c : Paraxial curvature (= 1 / radius of curvature), K: conic constant, C (m, n): free-form surface coefficient.

The optical performance of each of the embodiments is represented by a spot diagram (FIGS. 32, 34, 36, 38, 40, and 4).
2, FIG. 44) and distortion diagrams (FIGS. 33, 35, 37, 3)
9, FIG. 41, FIG. 43, and FIG. 45). The spot diagram shows the imaging characteristics (mm) on the screen surface (I2) at a wavelength of 550 (nm), and the distortion diagram shows the image on the screen surface (I2) corresponding to the rectangular mesh on the panel display surface (I1). Are shown (mm). In the distortion diagram, D1 (solid line) is the distortion lattice of the embodiment, and D0 (dotted line) is the lattice of ideal image points in consideration of the anamorphic ratio (no distortion). The x-axis is taken in the same direction as the x-axis, perpendicular to the x-axis, and on the panel display surface.
When the y-axis is taken in a direction parallel to (I1), the object height (mm) corresponding to each field position is the panel display surface (I1).
Is represented by coordinates (x, y) with the center of the screen at the origin. Also, X
Take the x 'axis in the same direction as the axis, perpendicular to the x' axis, and
When the y 'axis is taken in a direction parallel to the screen surface (I2), each image height (mm) is represented by coordinates (x', y ') with the screen center of the screen surface (I2) as the origin. You. Therefore, each distortion diagram is
Screen surface (I2) viewed from the direction perpendicular to the x'-y 'plane
This shows the distorted state of the actual image above (however, only the negative side of x ').

Example 1 Size (mm) of panel display surface (I1): 13.283 × 7.472 Size (mm) of screen surface (I2): 1106 × 622 FNO in screen long side direction = 3.0 screen short side FNO in direction = 3.0

[0053]

[Table 7]

[Curved Surface Shape of Fifth Mirror (m5)] Curvature Radius (mm) =-188.771 K = 1.242 × 10 ⁻¹ C (0,1) = 1.255 × 10 ⁻² , C (2,0) = − 4.349 × 10 ^-5 , C (0,2) =-1.999 × 10 ^-4 C (2,1) = 7.474 × 10 ^-8 , C (0,3) =-1.388 × 10 ^-7 , C (4, 0) = 5.376 × 10 ^-11 C (2,2) =-2.723 × 10 ^-9 , C (0,4) =-3.013 × 10 ^-9

[Curved Surface Shape of Fourth Mirror (m4)] Radius of Curvature (mm) = − 557.611 K = 1.089 × 10 ² C (0,1) = − 1.316 × 10 ⁻¹ , C (2,0) = − 1.040 × 10 ^-3 , C (0,2) =-2.954 × 10 ^-3 C (2,1) =-7.377 × 10 ^-6 , C (0,3) =-1.799 × 10 ^-5 , C (4 , 0) =-1.053 × 10 ^-7 C (2,2) =-3.890 × 10 ^-7 , C (0,4) =-3.419 × 10 ^-7

[Curved Surface Shape of Third Mirror (m3)] Curvature Radius (mm) = ∞ K = -5.324 × 10 ²² C (0,1) = 1.982, C (2,0) = 5.482 × 10 ^-3 , C (0,2) = 7.318 × 10 ^-3 C (2,1) = 3.730 × 10 ^-5 , C (0,3) = 2.690 × 10 ^-5 , C (4,0) = 1.506 × 10 ^-9 C (2,2) = 7.813 × 10 ^-8 , C (0,4) = 2.514 × 10 ^-8

Example 2 Size (mm) of panel display surface (I1): 13.283 × 7.472 Size (mm) of screen surface (I2): 1106 × 622 FNO in screen long side direction = 3.2 Screen short side FNO in direction = 3.2

[0058]

[Table 8]

[Curved Surface Shape of Fifth Mirror (m5)] Radius of Curvature (mm) =-191.092 K = 2.446 × 10 ⁻¹ C (0,1) = 6.143 × 10 ^-4 , C (2,0) = 7.436 × 10 ^-5 , C (0,2) =-3.168 × 10 ^-4 C (2,1) = 2.786 × 10 ^-7 , C (0,3) =-2.656 × 10 ^-7 , C (4,0 ) = 4.246 × 10 ^-9 C (2,2) = 1.675 × 10 ^-9 , C (0,4) =-3.293 × 10 ^-9

[Curved Surface Shape of Fourth Mirror (m4)] Curvature Radius (mm) = − 675.268 K = 1.805 × 10 ² C (0,1) = − 5.281 × 10 ⁻¹ , C (2,0) = − 5.155 × 10 ^-4 , C (0,2) =-9.120 × 10 ^-3 C (2,1) =-1.747 × 10 ^-5 , C (0,3) =-9.877 × 10 ^-5 , C (4 , 0) =-1.891 × 10 ^-8 C (2,2) =-7.092 × 10 ^-7 , C (0,4) =-1.365 × 10 ^-6

[Curved Surface Shape of Third Mirror (m3)] Curvature radius (mm) = ∞K = -5.324 × 10 ²² C (0,1) = 1.265, C (2,0) = 4.135 × 10 ^-3 , C (0,2) = - 1.730 × 10 -3 C (2,1) = 1.778 × 10 -5, C (0,3) = 3.035 × 10 -6, C (4,0) = 2.398 × 10 - ⁸ C (2,2) = 9.929 × 10 ^-9 , C (0,4) =-8.065 × 10 ^-8

Example 3 Size (mm) of panel display surface (I1): 13.283 × 7.472 Size (mm) of screen surface (I2): 1106 × 622 FNO in screen long side direction = 5.0 screen short side FNO in direction = 7.5

[0063]

[Table 9]

[Curved Surface Shape of Fifth Mirror (m5)] Curvature Radius (mm) =-189.831 K = 4.723 × 10 ⁻¹ C (0,1) =-9.384 × 10 ^-3 , C (2,0) = 1.183 × 10 ^-4 , C (0,2) =-4.932 × 10 ^-4 C (2,1) = 4.793 × 10 ^-7 , C (0,3) =-2.881 × 10 ^-7 , C (4, 0) = 8.343 × 10 ^-9 C (2,2) = 3.160 × 10 ^-9 , C (0,4) =-4.590 × 10 ^-9

[Curved Surface Shape of Fourth Mirror (m4)] Radius of Curvature (mm) = − 835.040 K = 4.475 × 10 ² C (0,1) = − 5.541 × 10 ⁻¹ , C (2,0) = − 1.898 × 10 ^-4 , C (0,2) =-1.104 × 10 ^-2 C (2,1) =-1.772 × 10 ^-5 , C (0,3) =-7.289 × 10 ^-5 , C (4 , 0) = 3.698 × 10 ^-8 C (2,2) =-1.540 × 10 ^-6 , C (0,4) =-2.023 × 10 ^-6

[Curved Surface Shape of Third Mirror (m3)] Curvature radius (mm) = ∞ K = −5.324 × 10 ²² C (0,1) = 1.355, C (2,0) = 5.156 × 10 ^-3 , C (0,2) = - 4.287 × 10 -3 C (2,1) = 2.619 × 10 -5, C (0,3) = 2.293 × 10 -5, C (4,0) = 1.444 × 10 - ⁷ C (2,2) =-3.921 × 10 ^-8 , C (0,4) =-9.628 × 10 ^-8

Example 4 Size (mm) of Panel Display Surface (I1): 13.283 × 7.472 Size (mm) of Screen Surface (I2): 1106 × 622 FNO in Longer Side of Screen = 3.1 Shorter Side of Screen FNO in direction = 3.1

[0068]

[Table 10]

[Curved Surface Shape of Fifth Mirror (m5)] Curvature Radius (mm) =-184.764 K = 1.891 × 10 ⁻¹ C (0,1) = 2.118 × 10 ⁻² , C (2,0) = − 1.269 × 10 ^-4 , C (0,2) =-1.774 × 10 ^-4 C (2,1) =-2.635 × 10 ^-7 , C (0,3) =-3.482 × 10 ^-7 , C (4 , 0) =-1.759 × 10 ^-9 C (2,2) =-3.883 × 10 ^-9 , C (0,4) =-2.273 × 10 ^-9

[Curved Surface Shape of Fourth Mirror (m4)] Radius of Curvature (mm) = − 399.486 K = 8.801 × 10 C (0,1) =-4.455 × 10 ⁻¹ , C (2,0) = − 1.526 × 10 ^-3 , C (0,2) =-2.606 × 10 ^-3 C (2,1) = 8.347 × 10 ^-6 , C (0,3) = 2.683 × 10 ^-7 , C (4,0) = -8.627 × 10 ^-8 C (2,2) =-4.166 × 10 ^-7 , C (0,4) =-3.986 × 10 ^-7

[Curved Surface Shape of Third Mirror (m3)] Curvature Radius (mm) = 0.152 K = -5.324 × 10 ²² C (0,1) = 1.308, C (2,0) = 4.029 × 10 ^-3 , C (0,2) = 5.679 × 10 -3 C (2,1) = 2.241 × 10 -5, C (0,3) = 1.711 × 10 -5, C (4,0) = - 3.608 × 10 - ⁹ C (2,2) = 3.436 × 10 ^-8 , C (0,4) = 1.656 × 10 ^-8

Example 5 Size (mm) of panel display surface (I1): 13.283 × 7.472 Size (mm) of screen surface (I2): 1106 × 622 FNO in screen long side direction = 3.1 Screen short side FNO in direction = 3.1

[0073]

[Table 11]

[Curved Surface Shape of Sixth Mirror (m6)] Curvature Radius (mm) = 106377.218 K = -9.439 × 10 ⁴ C (0,1) = 1.684 × 10 ⁻¹ , C (2,0) = − 2.258 × 10 ^-3 , C (0,2) =-2.369 × 10 ^-3 C (2,1) =-9.083 × 10 ^-6 , C (0,3) = 1.096 × 10 ^-5 , C (4,0 ) = 8.012 × 10 ^-9 C (2,2) =-4.285 × 10 ^-8 , C (0,4) = 2.231 × 10 ^-8

[Curved Surface Shape of Fifth Mirror (m5)] Curvature Radius (mm) = 267.910 K = -4.304 × 10 ⁻¹ C (0,1) = 4.674 × 10 ⁻² , C (2,0) = − 1.645 × 10 ^-4 , C (0,2) =-1.742 × 10 ^-4 C (2,1) = 6.569 × 10 ^-8 , C (0,3) = 1.008 × 10 ^-6 , C (4,0 ) = 7.508 × 10 ^-10 C (2,2) =-2.565 × 10 ^-10 , C (0,4) =-2.336 × 10 ^-9

[Curved Surface Shape of Fourth Mirror (m4)] Radius of Curvature (mm) = 570.148 K = -3.109 × 10 ² C (0,1) = 7.535 × 10 ⁻² , C (2,0) = 5.066 × 10 ^-4 , C (0,2) = 1.925 × 10 ^-3 C (2,1) =-1.293 × 10 ^-5 , C (0,3) =-6.269 × 10 ^-6 , C (4,0) = 2.246 × 10 ^-7 C (2,2) = 4.088 × 10 ^-7 , C (0,4) = 5.380 × 10 ^-8

[Curved Surface Shape of Third Mirror (m3)] Curvature Radius (mm) =-993.286 K = 2.645 × 10 C (0,1) = − 1.238, C (2,0) = − 1.032 × 10 ^-3 , C (0,2) = 1.167 × 10 -3 C (2,1) = 1.086 × 10 -5, C (0,3) = 6.456 × 10 -6, C (4,0) = 1.133 × 10 - ⁹ C (2,2) =-1.795 × 10 ^-7 , C (0,4) =-4.084 × 10 ^-8

Embodiment 6 Size (mm) of panel display surface (I1): 26.624 × 19.968 Size (mm) of screen surface (I2): 1024 × 768 FNO in screen long side direction = 3.0 screen short side FNO in direction = 4.5

[0079]

[Table 12]

[Curved Surface Shape of Sixth Mirror (m6)] Radius of curvature (mm) = 47670.865 K = -6.434 × 10 ⁴ C (0,1) = 2.113 × 10 ⁻¹ , C (2,0) =-9.706 × 10 ^-4 , C (0,2) =-1.863 × 10 ^-3 C (2,1) = 7.277 × 10 ^-6 , C (0,3) = 5.779 × 10 ^-6 , C (4,0) = 1.856 × 10 ^-8 C (2,2) = 1.133 × 10 ^-7 , C (0,4) = 9.931 × 10 ^-8

[Curved Surface Shape of Fifth Mirror (m5)] Curvature Radius (mm) = 266.862 K = -9.462 × 10 ⁻¹ C (0,1) = − 1.537 × 10 ⁻² , C (2,0) = -1.508 × 10 ^-4 , C (0,2) =-1.841 × 10 ^-4 C (2,1) = 7.947 × 10 ^-8 , C (0,3) = 2.548 × 10 ^-7 , C (4, 0) = 5.091 × 10 ^-9 C (2,2) = 9.101 × 10 ^-9 , C (0,4) = 3.779 × 10 ^-9

[Curved Surface Shape of Fourth Mirror (m4)] Curvature Radius (mm) = 511.833 K = −1.186 × 10 ² C (0,1) = 1.197 × 10 ⁻¹ , C (2,0) = 6.380 × 10 ^-4 , C (0,2) = 1.251 × 10 ^-3 C (2,1) =-4.052 × 10 ^-6 , C (0,3) =-3.980 × 10 ^-6 , C (4,0) = 1.494 × 10 ^-7 C (2,2) = 2.385 × 10 ^-7 , C (0,4) = 6.638 × 10 ^-8

[Curved Surface Shape of Third Mirror (m3)] Curvature Radius (mm) = 0.000 K = −1.879 × 10 ² C (0,1) = − 2.058, C (2,0) = − 8.631 × 10 ^{− 4} , C (0,2) = 1.908 × 10 ^-3 C (2,1) = 5.097 × 10 ^-6 , C (0,3) = 6.368 × 10 ^-6 , C (4,0) = 2.201 × 10 ^-9 C (2,2) =-5.440 × 10 ^-8 , C (0,4) =-2.417 × 10 ^-8

<< Embodiment 7 >> Size (mm) of panel display surface (I1): 13.283 × 7.472 Size (mm) of screen surface (I2): 1106 × 622 FNO in screen long side direction = 3.1 Screen short side FNO in direction = 3.1

[0085]

[Table 13]

[Curved Surface Shape of Sixth Mirror (m6)] Curvature Radius (mm) = 55105.558 K = −9.416 × 10 ⁴ C (0,1) = 2.665 × 10 ⁻¹ , C (2,0) = − 1.488 × 10 ^-3 , C (0,2) =-2.314 × 10 ^-3 C (2,1) = 7.735 × 10 ^-6 , C (0,3) = 1.046 × 10 ^-5 , C (4,0) = 8.701 × 10 ^-9 C (2,2) = 1.657 × 10 ^-7 , C (0,4) = 8.682 × 10 ^-8

[Curved Surface Shape of Fifth Mirror (m5)] Curvature Radius (mm) = 266.893 K = 5.482 × 10 ⁻¹ C (0,1) = 3.794 × 10 ^-4 , C (2,0) = − 1.355 × 10 ^-4 , C (0,2) =-1.900 × 10 ^-4 C (2,1) = 3.553 × 10 ^-7 , C (0,3) = 6.314 × 10 ^-7 , C (4,0) = -5.225 × 10 ^-9 C (2,2) =-1.127 × 10 ^-8 , C (0,4) =-6.737 × 10 ^-9

[Curved Surface Shape of Fourth Mirror (m4)] Curvature Radius (mm) = 669.724 K = −3.507 × 10 ² C (0,1) = 9.594 × 10 ⁻² , C (2,0) = 9.897 × 10 ^-4 , C (0,2) = 1.845 × 10 ^-3 C (2,1) =-3.058 × 10 ^-6 , C (0,3) =-6.449 × 10 ^-6 , C (4,0) = 2.237 × 10 ^-7 C (2,2) = 4.923 × 10 ^-7 , C (0,4) = 1.248 × 10 ^-7

[Curved Surface Shape of Third Mirror (m3)] Curvature Radius (mm) =-1508.718 K = 6.332 × 10 C (0,1) = − 1.224, C (2,0) = − 4.739 × 10 ⁻⁴ , C (0,2) = 1.439 × 10 ^-3 C (2,1) =-3.909 × 10 ^-7 , C (0,3) = 4.994 × 10 ^-6 , C (4,0) =-2.171 × 10 ^-8 C (2,2) =-1.135 × 10 ^-7 , C (0,4) =-2.627 × 10 ^-8

[0090]

[Table 14]

Next, a projection optical system comprising a catadioptric optical system
The structure of (PS) will be described more specifically with reference to construction data, a spot diagram, and the like. The eighth embodiment described here as an example is a projection optical system (PS) used in the seventh embodiment of the type 1 (FIG. 8) and the thirteenth embodiment of the type 2 (FIG. 16). It is. The size described in FIG. 8 and FIG.
The projection optical system (PS) is applied to a rear projection display device. FIG. 46 shows the entire projection optical path from the panel display surface (I1) to the screen surface (I2) of the eighth embodiment, and FIG. 47 shows the optical configuration and a main part of the projection optical path of the eighth embodiment.

In the construction data of the eighth embodiment, si (i = 1, 2, 3,...) Is the panel display surface (I1) on the reduction side.
In the system including the screen surface (I2) on the enlargement side and the screen surface (I2), the i-th surface counted from the reduction side, and ri (i = 1, 2, 3, ...) is the surface
This is the radius of curvature (mm) of si. Di (i = 1,2,3, ...)
The i-th shaft upper surface interval counted from the reduction side (mm, the eccentric surface interval is described as eccentricity data) is shown, and Ni (i = 1, 2,
3, ...) and νi (i = 1,2,3, ...) indicate the refractive index (Nd) and Abbe number (νd) for the d-line of the i-th optical element counted from the reduction side, respectively. ing. The surface si marked with * is an axisymmetric aspheric surface, and its surface shape is a rectangular coordinate system whose origin is the surface vertex.
It is defined by the following equation (AS) using (x, y, z). The surface si with a $ mark is a free-form surface, and its surface shape is defined by the above-described formula (FS) using an orthogonal coordinate system (x, y, z) with the surface vertex as the origin. Aspherical surface data and free-form surface data are shown together with other data.

Z = (c · h ² ) / [1 + √ {1-c ² · h ² }] + (A · h ⁴ + B · h ⁶ + C · h ⁸ + D · h ¹⁰ )… ( AS) where z: displacement from the reference plane in the optical axis direction at the position of height h, h: height in the direction perpendicular to the optical axis (h ² = x ² + y ² ), c: Paraxial curvature (= 1 / radius of curvature), A, B, C, D: aspheric coefficients.

For the plane eccentric to the plane located immediately before the reduction side, the eccentricity data is shown based on the rectangular coordinate system (X, Y, Z). In the rectangular coordinate system (X, Y, Z), the vertex coordinates of the plane (XDE, X), with the center position of the panel display surface (s1) as the origin (0, 0, 0)
YDE, ZDE) = {parallel eccentric position in the X-axis direction (mm), parallel eccentric position in the Y-axis direction (mm), parallel eccentric position in the Z-axis direction (mm)} The rotation angle ADE (°) about the X axis about the surface vertex of the surface indicates the rotational eccentric position (in the optical path diagram, the counterclockwise direction toward the paper surface is positive). In the optical path diagram, the X axis direction is perpendicular to the paper surface.
(The back side of the paper surface is assumed to be positive.) The Y-axis direction is a straight line direction where the panel display surface (s1) intersects the paper surface (the upper side of the optical path diagram is assumed to be positive), and the Z-axis direction is panel display. {The screen surface (I2) side, which is the normal direction of the surface (s1), is assumed to be positive. }.

The optical performance of Example 8 is shown by a spot diagram (FIG. 48) and a distortion diagram (FIG. 49). The spot diagram shows the imaging characteristics (mm) on the screen surface (I2) as d.
The three wavelengths of the line, the g-line and the c-line are shown, and the distortion diagram shows the ray position (mm) on the screen surface (I2) corresponding to the rectangular mesh on the panel display surface (I1). In the distortion diagram,
D1 (solid line) is a distorted lattice of the embodiment, and D0 (dotted line) is a lattice of ideal image points (without distortion) in consideration of the anamorphic ratio. In addition,
Take the x-axis in the same direction as the x-axis, perpendicular to the x-axis, and
When the y-axis is taken in a direction parallel to the panel display surface (I1), the object height is represented by coordinates (x, y) with the origin at the center of the screen of the panel display surface (I1). Also, take the x 'axis in the same direction as the X axis,
If the y 'axis is taken in a direction perpendicular to the x' axis and parallel to the screen plane (I2), the image height will be
It is expressed by coordinates (x ', y') with the screen center of 2) as the origin. Therefore, each distortion diagram shows the distortion state of the actual image on the screen surface (I2) viewed from the direction perpendicular to the x'-y 'plane (however, only the negative side of x'). .

<< Eighth Embodiment >> [Surface] [Radius of Curvature, etc.] [Space of Upper Surface of Shaft] [Refractive Index] [Abbe Number] Panel Display Surface (I1) s1 r1 = 1 Prism Block (Pr) s2 r2 = XDE = 0.000000, YDE = 0.000000, ZDE = 2.000000, ADE = 8.231146 d2 = 25.000000 N1 = 1.516800 ν1 = 64.17 s3 r3 = ∞ First refractive lens group (G1)… s4 * r4 = 46.70870 A = -0.143476 × 10 ^-4 , B = 0.336127 × 10 ^-7 , C = -0.100793 × 10 ^-9 D = 0.169578 × 10 ^-12 XDE = 0.000000, YDE = -0.209423, ZDE = 27.884859, ADE = 2.863299 d4 = 5.054112 N2 = 1.516800 ν2 = 64.17 s5 r5 = -23.80876 Second refractive lens group (G2) ... s6 r6 = 17.16844 XDE = 0.000000, YDE = -3.800929, ZDE = 37.839776, ADE = -5.724528 d6 = 8.214673 N3 = 1.754500 ν3 = 51.5700 s7 r7 = -183.84669 d7 = 0.437109 s8 r8 = -36.61565 d8 = 0.550000 N4 = 1.634801 ν4 = 31.1517 s9 r9 = 11.51501 d9 = 2.998133 s10 r10 = -14.20564 d10 = 3.078071 N5 = 1.646976 ν5 = 30.1061 s11 r11 = -36.35912 d12 = 12.1112.1297. = 1.254406 N6 = 1.754500 ν6 = 51.5700 s13 r13 = -19.09051 d13 = 0.100000 Aperture (ST) ... s14 r14 = ∞ (Aperture radius = 5.528787) Curved reflecting mirror (R1) ... s15 $ r15 = -515.18948 XDE = 0.000000, YDE = -3.880643, ZDE = 162.698182, ADE = 40.395892 K = 0.000000 C (0,1) = 4.5091 × 10 -1, C (2,0 ) =-3.9754 × 10 ^-4 , C (0,2) =-4.3444 × 10 ^-4 C (2,1) =-9.2883 × 10 ^-6 , C (0,3) =-8.9339 × 10 ^-6 , C (4,0) =-3.3775 × 10 ^-8 C (2,2) =-6.0399 × 10 ^-8 , C (0,4) = 3.4705 × 10 ^-8 , C (4,1) = 2.9641 × 10 ^-9 C (2,3) = 3.7180 × 10 ^-9 , C (0,5) = 2.9922 × 10 ^-9 , C (6,0) = 3.7758 × 10 ^-11 C (4,2) = 8.4198 × 10 ^-11 , C (2,4) = 1.0632 × 10 ^-10 , C (0,6) = 2.4061 × 10 ^-11 C (6,1) =-9.7584 × 10 ^-13 , C (4,3) = 1.2522 × 10 ^-12 , C (2,5) = 1.7911 × 10 ^-12 C (0,7) =-6.4844 × 10 ^-13 , C (8,0) =-1.6691 × 10 ^-14 , C (6,2 ) =-1.7447 × 10 ^-15 C (4,4) = 1.8389 × 10 ^-14 , C (2,6) = 1.7057 × 10 ^-14 , C (0,8) =-1.2407 × 10 ^-14 Free-form surface reflection Mirror (R2) ... s16 $ r16 = 11790.68206 XDE = 0.000000, YDE = -221.232416, ZDE = -1.216178, ADE = 63.818350 K = 0.000000 C (0,1) = 1.9367, C (2,0) =-2.5631 × 10 ^-3 , C (0,2) =-7.1973 × 10 ^-3 C (2,1) = 9.2605 × 10 ^-6 , C (0,3) = 2.1326 × 10 ^-4 , C (4,0) = 8.9157 × 10 ^-8 C (2,2) =-2.1518 × 10 ^-6 , C (0,4) =-6.9456 × 10 ^-7 , C (4,1) =-4.4593 × 10 ^-9 C (2,3 ) = 5.9549 × 10 ^-8 , C (0,5) =-1.5015 × 10 ^-7 , C (6,0) =-4.7449 × 10 ^-11 C (4,2) = 2.8377 × 10 ^-10 , C ( ^{2,4) = - 9.6994 × 10 -10} , C (0,6) = 4.0579 × 10 -9 C (6,1) = - 4.8820 × 10 -14, C (4,3) = - 6.0060 × 10 - ¹² , C (2,5) = 8.4012 × 10 ^-12 C (0,7) =-4.5581 × 10 ^-11 , C (8,0) = 1.1592 × 10 ^-14 , C (6,2) = 3.5666 × 10 ^-15 C (4,4) = 4.7297 × 10 ^-14 , C (2,6) =-3.0020 × 10 ^-14 , C (0,8) = 1.9608 × 10 ^-13 Screen surface (I2)… s17 r17 = ∞ XDE = 0.000000, YDE = -791.632950, ZDE = 1233.624811, ADE = 17.190021

[0097]

As described above, according to the present invention, it is possible to realize a rear projection display device which achieves thinness and compactness while maintaining good optical performance.

[Brief description of the drawings]

FIG. 1 is an optical configuration diagram showing a basic configuration of a type 1 plane mirror system.

FIG. 2 is an optical configuration diagram showing the first embodiment.

FIG. 3 is an optical configuration diagram showing a second embodiment.

FIG. 4 is an optical configuration diagram showing a third embodiment.

FIG. 5 is an optical configuration diagram showing a fourth embodiment.

FIG. 6 is an optical configuration diagram showing a fifth embodiment.

FIG. 7 is an optical configuration diagram showing a sixth embodiment.

FIG. 8 is an optical configuration diagram showing a seventh embodiment.

FIG. 9 is an optical configuration diagram showing a basic configuration of a type 1 ′ plane mirror system.

FIG. 10 is an optical configuration diagram showing an eighth embodiment.

FIG. 11 is an optical configuration diagram showing a basic configuration of a type 2 plane mirror system.

FIG. 12 is an optical configuration diagram showing a ninth embodiment.

FIG. 13 is an optical configuration diagram showing a tenth embodiment.

FIG. 14 is an optical configuration diagram showing an eleventh embodiment.

FIG. 15 is an optical configuration diagram showing a twelfth embodiment.

FIG. 16 is an optical configuration diagram showing a thirteenth embodiment.

FIG. 17 is an optical configuration diagram showing a basic configuration of a type 2 ′ plane mirror system.

FIG. 18 is an optical configuration diagram showing a fourteenth embodiment.

FIG. 19 is an optical configuration diagram showing a basic configuration of a type 3 plane mirror system.

FIG. 20 is an optical configuration diagram showing a fifteenth embodiment.

FIG. 21 is an optical configuration diagram showing a sixteenth embodiment.

FIG. 22 is an optical configuration diagram showing a seventeenth embodiment.

FIG. 23 is an optical configuration diagram showing an eighteenth embodiment.

FIG. 24 is an optical configuration diagram showing a nineteenth embodiment (type 3 ′).

FIG. 25 is an optical configuration diagram showing the first embodiment.

FIG. 26 is an optical configuration diagram showing a second embodiment.

FIG. 27 is an optical configuration diagram showing a third embodiment.

FIG. 28 is an optical configuration diagram showing a fourth embodiment.

FIG. 29 is an optical configuration diagram showing a fifth embodiment.

FIG. 30 is an optical configuration diagram showing a sixth embodiment.

FIG. 31 is an optical configuration diagram showing a seventh embodiment.

FIG. 32 is a spot diagram of Example 1.

FIG. 33 is a distortion diagram of the first embodiment.

FIG. 34 is a spot diagram of Example 2.

FIG. 35 is a distortion diagram of the second embodiment.

FIG. 36 is a spot diagram of Example 3.

FIG. 37 is a distortion diagram of the third embodiment.

FIG. 38 is a spot diagram of Example 4.

FIG. 39 is a distortion diagram of the fourth embodiment.

FIG. 40 is a spot diagram of Example 5.

FIG. 41 is a distortion diagram of the fifth embodiment.

FIG. 42 is a spot diagram of Example 6.

FIG. 43 is a distortion diagram of the sixth embodiment.

FIG. 44 is a spot diagram of Example 7.

FIG. 45 is a distortion diagram of the seventh embodiment.

FIG. 46 is an optical path diagram of a projection optical system according to an eighth embodiment.

FIG. 47 is a diagram illustrating an optical configuration of a projection optical system and a main part of a projection optical path according to an eighth embodiment.

FIG. 48 is a spot diagram of Example 8.

FIG. 49 is a distortion diagram of the eighth embodiment.

[Explanation of symbols]

 I1 ... panel display surface I2 ... screen surface ST ... stop position (stop) PS ... projection optical system MS ... plane mirror system M1 ... first mirror (first plane reflection surface) M2 ... second mirror (second plane reflection surface) M3: Third mirror (third flat reflecting surface) m3: Third mirror (free curved reflecting surface) m4: Fourth mirror (free curved reflecting surface) m5: Fifth mirror (free curved reflecting surface) m6: sixth mirror (Free-form surface reflection surface) R1… Free-form surface reflection mirror (Free-form surface reflection surface) R2… Free-form surface reflection mirror (Free-form surface reflection surface)

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kenji Kanno 2-3-113 Azuchicho, Chuo-ku, Osaka City International Building Minolta Co., Ltd. F-term (reference) 2H087 KA06 KA07 LA01 RA06 RA12 RA13 RA45 TA01 TA02 TA06 5C058 EA01 EA13 EA32 EA42 9A001 BB06 HH34 JJ71 KK16 KK63

Claims (6)

[Claims] 1. A rear projection system comprising: a non-axially symmetric projection optical system for obliquely projecting an image on a panel display surface onto a screen surface; and a plane mirror system for bending an optical path from the projection optical system to the screen surface. A display device, wherein the projection optical system has at least one free-form surface reflection surface, and the plane mirror system has a first surface facing the screen surface.
A plane reflecting surface having at least two plane reflecting surfaces; a light beam emitted from the projection optical system is reflected by the second plane reflecting surface; The projection optical system and the plane mirror system are arranged such that, after being reflected by a surface, the projection optical system crosses an optical path from the projection optical system to the second plane reflection surface and reaches the screen surface. Rear projection display device. 2. A screen center ray is defined as a light ray that reaches the center of the screen of the screen surface from the center of the screen of the panel display surface and reaches the center of the screen of the screen surface. 2. The rear projection display device according to claim 1, wherein the following conditional expression is satisfied when a light ray reaching the outermost periphery of the screen of the surface is defined as a peripheral light ray of the screen: S1> D / cosαu + D · (tanαl-tanαu). + HD> 2 · E · tan {(αl−αu) / 2} where αu = tan ⁻¹ {(S1 · sinα−H / 2) / (S1 · cosα)} αl = tan ⁻¹ {(S1 · sinα + H / 2) / (S1 · cosα)} E = 0.8 · (S1−1.5 · D / cosα) S1: The exit pupil position of the projection optical system or the optics of the center ray of the screen from the final surface of the projection optical system to the screen surface. Distance, D: at the screen surface at the optical distance of the center ray of the screen from the first plane reflecting surface to the screen surface H: the size of the screen surface in the direction parallel to the plane defined by the screen surface normal and the screen center ray, α: the incident angle of the screen center ray with respect to the screen surface, αu: the screen surface Is the incident angle of the screen marginal ray reaching the center of the upper side of the screen with respect to the screen surface, and αl is the incident angle of the screen marginal ray reaching the center of the lower side of the screen with respect to the screen plane. 3. A rear projection system comprising: a non-axisymmetric projection optical system for obliquely projecting an image on a panel display surface onto a screen surface; and a plane mirror system for bending an optical path from the projection optical system to the screen surface. A display device, wherein the projection optical system has at least one free-form surface reflection surface, and the plane mirror system has a first surface facing the screen surface.
At least two of a planar reflective surface and a second planar reflective surface positioned near the screen surface substantially parallel to the screen surface.
Having a plane reflecting surface, so that a light beam emitted from the projection optical system is reflected by the second plane reflecting surface, further reflected by the first plane reflecting surface, and then reaches the screen surface. Wherein the projection optical system and the plane mirror system are arranged, and a ray reaching the center of the screen of the screen surface from the center of the screen of the panel display surface through the center of the aperture is defined as a center ray of the screen. Α> 45 ° D <H / 2, where α is the incident angle of the screen center ray with respect to the screen surface, and D is the screen center from the first plane reflecting surface to the screen surface. H: the size of the screen surface in the direction parallel to the plane formed by the normal line of the screen surface and the central ray of the screen, in the component perpendicular to the screen surface in the optical distance of the light beam. 4. A light beam that passes from the outermost periphery of the screen of the panel display surface to the outermost periphery of the screen of the screen surface through the center of the aperture is defined as a peripheral light of the screen, and further satisfies the following conditional expression. 4. The rear projection display device according to claim 3, wherein S1> 2 · D / cos α 2 · D · tanαl> H, where α1 = tan ^-1 {(S1 · sinα + H / 2) / (S1 · cosα)} α1: screen S1 is the angle of incidence of the peripheral light of the screen reaching the center of the lower side of the screen with respect to the screen, S1: the exit pupil position of the projection optical system or the optical distance of the center light of the screen from the final plane of the projection optical system to the screen. 5. A rear projection system comprising: a non-axisymmetric projection optical system for obliquely projecting an image on a panel display surface onto a screen surface; and a plane mirror system for bending an optical path from the projection optical system to the screen surface. A display device, wherein the projection optical system has at least one free-form surface reflection surface, and the plane mirror system has a first surface facing the screen surface.
The light source has at least two planar reflecting surfaces, a planar reflecting surface and a second planar reflecting surface, and a light beam emitted from the projection optical system is reflected by the first planar reflecting surface; The rear projection display device, wherein the projection optical system and the plane mirror system are arranged so as to reach the screen surface after being reflected by a surface. 6. A screen center ray is defined as a light ray that reaches the center of the screen of the screen surface from the center of the screen on the panel display surface and reaches the center of the screen of the screen. The rear projection display device according to claim 5, wherein the following conditional expression is satisfied when a light ray reaching the outermost periphery of the screen is defined as a screen peripheral light ray: S1> D / cosα D · tanαl> H Α1 = tan ⁻¹ {(S1 · sinα + H / 2) / (S1 · cosα)} S1: The exit pupil position of the projection optical system or the optical distance of the center ray of the screen from the final surface of the projection optical system to the screen surface, D : A component in the direction perpendicular to the screen surface in the optical distance of the screen center ray from the first plane reflecting surface to the screen surface, H: in the direction parallel to the plane formed by the screen surface normal and the screen center ray Screen surface The size, α: the incident angle of the screen center ray to the screen surface, αl: the incident angle of the screen peripheral ray reaching the center of the lower side of the screen surface to the screen surface.