JP2000089227A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device in which distortion and blur are not present in a picture which is to be obtained by projecting a picture on a picture display panel on the screen arranged in an oblique direction and in which the total size of an optical system capable of projecting the picture while having a high optical performance is miniaturized by using an off-axial optical system. SOLUTION: This device is a projection type display device projecting the picture on a picture display panel 3 on a screen 5 by a projection optical system. In this device, a center line connecting the center of the picture display panel 3 and the center of the projected picture is not vertical to at least one side of the surface of the picture display panel 3 or the surface of the screen 5 and the projection optical system has at least one of an off-axial optical block 4 which includes an off-axial surface being an aspherical shape having 0 or one of the symmetric surface of a broad sense and has refractive power capable of forming a real image on the whole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device, and more particularly to a projection type display device suitable for a liquid crystal projector which enlarges and projects an image of a liquid crystal display element (liquid crystal panel) on a screen or a wall by a projection lens.

[0002]

2. Description of the Related Art Conventionally, various liquid crystal projectors have been proposed in which a liquid crystal panel is illuminated by a light beam from a light source and an image based on transmitted light or reflected light from the liquid crystal panel is enlarged and projected on a screen or a wall by a projection lens. Have been.

FIG. 9 is a schematic view of a main part of a conventional projection display device. In the figure, 101 is an illumination system, 102 is an image display panel such as a liquid crystal, 103 is a projection optical system, and 104 is a screen. An image formed on the image display panel 102 is illuminated by the illumination system 101, and is enlarged and projected on a screen 104 provided in an oblique direction via a projection optical system 103, whereby an image is displayed.

On the other hand, recently, various image forming systems using a non-coaxial optical system to reduce the size of the entire optical system have been proposed. In the non-coaxial optical system, it is possible to construct an optical system in which aberration is sufficiently corrected by introducing the concept of the reference axis and making the constituent surface an asymmetrical aspheric surface.
No. 50 discloses a design method thereof, and JP-A-8-292371 and JP-A-8-292372 show design examples thereof.

Such a non-coaxial optical system is an off-axial optical system (when considering a reference axis along a ray passing through the center of the image and the center of the pupil, the surface normal at the intersection with the reference axis of the constituent surface is on the reference axis. The optical system is defined as an optical system including a curved surface (off-axial curved surface), in which case the reference axis has a bent shape. In this off-axial optical system, the constituent surface is generally non-coaxial, and there is no vignetting even on the reflecting surface. Therefore, it is easy to construct an optical system using the reflecting surface. In addition, the optical path can be relatively freely routed, and it is easy to form an integrated optical system by a method of integrally molding the constituent surfaces.

[0006]

As shown in FIG. 9, in a projection type display device in which a light beam of a projection optical system 103 is projected obliquely onto a screen 104, a screen 104 is used.
The relative positional relationship between the projection optical system 103 and the projection optical system 103 may vary depending on the conditions of use. In particular, when the optical axis 105 of the projection optical system 103 and the screen 104 are not in a right angle relationship, a trapezoidal distortion occurs in the projected image due to the tilting effect.

FIG. 10 is a schematic diagram for explaining that trapezoidal distortion is caused by oblique projection. An image (arrow in FIG. 10) formed on the display panel 102 is a projection lens 103.
Is obliquely projected on the screen 104 at an angle θ. It is well known that the relationship between an object and an image in such an arrangement is generated in a tilt photographing or the like. Display panel 1
02 to the object-side principal point of the projection lens 103 is L
1. From the image side principal point of the projection lens 103 to the screen 104
To the origin 104 of the screen 104
a is the optical axis 105 of the projection lens 103 and the screen 104
And the intersection with Imaging magnification in the height H of the screen 104 beta is, β = (L2 + Hsin θ ) / L1 = β 0 + (sinθ / L1) H (1) and made it is obtained by calculation of the paraxial.

Here, β ₀ indicates a projection magnification at the origin of the screen. From equation (1), it can be seen that the projection magnification β on the screen is a linear function with respect to the vertical height H of the screen 104. This relationship is peculiar to tilt, and if θ is set to 0, the magnification β is always β
_It is equal to ₀ . The relationship between the magnification β and the height H when θ ≠ 0 is as shown in FIG. 11, where the magnification is larger than the center when the height H is positive, and vice versa when the height H is negative. Become. As a result, when a square image is input to the display panel, the image formed on the screen has a trapezoidally distorted shape as shown by the solid line in FIG. FIG.
The middle and dashed lines show images without distortion.

Also, reference numeral 106 in FIG. 10 denotes a paraxial Gaussian image plane. However, since the paraxial Gaussian image plane 106 and the screen 104 do not coincide with each other, focusing is not performed where the image height H is large, so that the entire screen is sharp. It is difficult to obtain a proper projected image. Since these aberrations such as trapezoidal distortion and image plane tilt are not rotationally symmetric with respect to the optical axis, these problems have been inevitable in a projection type display apparatus conventionally configured with a rotationally symmetric optical system.

On the other hand, Japanese Patent Application Laid-Open No. Hei 3-113432 discloses a projection type display device in which a projection lens is shifted in a direction perpendicular to an optical axis to prevent distortion of a projected image. In general, when a rotationally symmetric lens is shifted, the projection resolution tends to decrease due to the aberration caused by the shift.

According to the present invention, an off-axial optical system is used to project an image on an image display panel onto a screen surface arranged in an oblique direction without distortion or blur in the projected image while maintaining high optical performance. It is an object of the present invention to provide a projection display device in which the size of the entire optical system can be reduced.

[0012]

According to the present invention, there is provided a projection display apparatus for projecting an image on an image display panel onto a screen by a projection optical system. The center line connecting the center of the panel and the center of the projected image is not perpendicular to at least one of the image display panel surface or the screen surface, and the projection optical system has an aspheric shape having 0 or 1 broadly defined symmetry plane. It is characterized by having at least one off-axial optical block having a refractive power capable of forming a real image as a whole, including an off-axial surface as a constituent element.

In particular, (1-1-1) the off-axial optical block is characterized by including at least one off-axial reflecting surface as a constituent element.

(1-2) A projection display device for projecting an image on an image display panel onto a screen by a projection optical system, wherein a center line connecting the center of the image display panel and the center of the projected image is defined by The projection optical system is not perpendicular to at least one of the image display panel surface or the screen surface, and the projection optical system includes at least one off-axial optical block having a refractive power capable of forming a real image as a whole and including an off-axial reflection surface as a component. It is characterized by:

(1-3) Projection in which a light beam from a light source is condensed by an illumination optical system, an image display panel is illuminated with the light beam, and an image on the image display panel is projected on a screen surface by a projection optical system. In the type display device, a center line connecting the center of the light source and the center of the image display panel is not perpendicular to the image display panel surface, and the illumination optical system has an off-axial reflecting surface including an off-axial reflecting surface as a component. It is characterized by including at least one optical block.

In addition, in the constitutions (1-1) to (1-3), (1-3-1) the image display panel is a reflection type image display which spatially modulates the intensity of an incident light beam and reflects it. Be a panel.

(1-3-2) The off-axial reflecting surface is configured to reflect light rays incident from the air side to the air side.

(1-3-3) The off-axial reflecting surface is configured to reflect light rays incident from the medium side to the medium side.

(1-3-4) The off-axial optical block is made by molding.

(1-3-5) At least two of the plurality of optical surfaces constituting the off-axial optical block are integrally formed by molding.

(1-3-6) The off-axial optical block has an incident surface on which a light beam is refracted and incident on the surface of the transparent body;
It is characterized by comprising an optical element in which a plurality of reflecting surfaces having a curvature for sequentially reflecting the incident light beam and an exit surface for refracting and emitting the light beam reflected by the plurality of reflecting surfaces are integrally formed. And

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing specific embodiments of the present invention, they will be used frequently in this specification.
An off-axial optical system and a reference axis which is a skeleton thereof are defined as follows.

Definition of Reference Axis Generally, the optical path of a light beam having a reference wavelength from the object plane to the image plane as a reference is defined as a reference axis in the optical system.
This alone leaves ambiguity in the method of selecting the reference light beam, so that the reference light beam, that is, the reference axis is usually set by one of the following two principles.

(A-1) In the case where an axis having a symmetry exists even in a part of the optical system and aberration can be collected with good symmetry, a ray passing through the axis having the symmetry is used as a reference. Light rays.

(A-2) In general, when the axis of symmetry does not exist in the optical system, or when the aberration cannot be collected with good symmetry even though the axis of symmetry exists partially, the center of the object plane (the object Of the light rays emitted from the (photographing, center of the observation range), light rays passing through the optical system in the order of the designated surface of the optical system and passing through the center of the aperture defined in the optical system are set as reference light rays.

The reference axis defined in this manner generally has a bent shape.

Definition of Off-Axial Optical System At the point where the reference axis defined as described above intersects the curved surface, a curved surface whose surface normal does not coincide with the reference axis is defined as an off-axial curved surface, and an optical system including an off-axial curved surface is defined. It is defined as an off-axial optical system. (However, even when the reference axis is simply bent by the plane reflecting surface, the surface normal does not coincide with the reference axis. However, since the plane reflecting surface does not impair the symmetry of aberration, it is excluded from the target of the off-axial optical system. Hereinafter, an embodiment of the projection type display device of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a projection display apparatus according to a first embodiment of the present invention.

In the figure, 1 is a light source, 2 is a condenser lens for converting light from the light source 1 into parallel light of uniform intensity, and 3 is an image display using a liquid crystal or the like which spatially modulates the intensity distribution of the parallel light. It is a panel. 14 is an image display panel 3
A projection optical system for projecting the above image onto the screen 5,
The projection optical system 14 includes an off-axial optical block 4 in which a plurality of optical surfaces are integrally formed. The off-axial optical block 4 includes an incident refracting surface R2, reflecting surfaces R3 and R4, and an outgoing refracting surface R5. The image display panel 14 is moved in the reference axis direction to perform focus adjustment.

FIG. 2 is an explanatory diagram of a coordinate system that defines the configuration data of each optical surface of the projection display device of the present invention.

In the embodiment of the present invention, the i-th surface is set along one light ray (shown by a dashed line in FIG. 2 and referred to as a reference axis light ray La) traveling from the element surface of the image display panel 3 to the screen 5. The i-th surface.

In FIG. 2, the first surface R1 is an element surface of the image display panel 3, the second surface R2 is a refracting surface, the third surface R3 and the fourth surface R4 are off-axial reflecting surfaces, and the fifth surface R5 is a refracting surface. is there.

Since the projection optical system 14 according to the present invention utilizes an off-axial optical system, the surfaces constituting the optical system do not have a common optical axis. Therefore, in the embodiment of the present invention, first, an absolute coordinate system having the center of the object plane 3 as the origin is set. In the embodiment of the present invention, the center point of the object plane is set as the origin, and the path of a light ray (reference axis light ray) passing through the origin and the center of the image plane is defined as the reference axis of the optical system. Further, the reference axis in this embodiment has a direction (direction). This direction is the direction in which the reference axis ray La travels during image formation. The reference axis can be handled in the same manner as the optical axis when viewed from outside the optical system.

In the embodiment of the present invention, the reference axis serving as the reference of the optical system is set as described above. However, the method of determining the reference axis of the optical system depends on optical design, integration of aberrations, or optical system. The axis which is convenient in expressing the shape of each surface constituting the above may be adopted.

However, in general, the path of the light beam passing through the center of the image plane or the observation plane and either the stop, the entrance pupil or the exit pupil, or the center of the first surface or the center of the last surface of the optical system is defined by the optical system. Set to the reference axis that is the reference for

That is, in the embodiment of the present invention, the reference axis passes through the center point of the image display panel 3 and the path on which the light reaching the center of the image plane (reference axis light) is reflected by the reflecting surface is set as the reference axis. are doing. The order of each surface is set in the order in which the reference axis rays are reflected.

Accordingly, the reference axis finally reaches the center of the image plane while changing its direction along the set order of each surface according to the law of reflection.

The tilt surfaces constituting the optical system of each embodiment of the present invention are basically all tilted in the same plane. Therefore, each axis of the absolute coordinate system is determined as follows.

Z axis: Reference axis toward the second surface R1 passing through the origin Y axis: Straight line passing through the origin and forming 90 ° counterclockwise with respect to the Z axis in the tilt plane (in the paper of FIG. 2) : A straight line passing through the origin and perpendicular to each of the Z and Y axes (a straight line perpendicular to the paper of FIG. 2). , The reference axis and the i-th
The configuration data of the present invention is displayed because it is easier to understand the shape of the surface by setting the local coordinate system having the origin at the point where the surface intersects and expressing the surface shape of the surface in the local coordinate system. In the embodiment, the surface shape of the i-th surface is represented by a local coordinate system.

The tilt angle of the i-th surface in the YZ plane is an angle θ with the counterclockwise direction being positive with respect to the Z axis of the absolute coordinate system.
i (unit: °). Therefore, in the embodiment of the present invention, the origin of the local coordinates of each surface is on the YZ plane in FIG.

There is no eccentricity of the plane in the XZ and XY planes.
Further, the y, z axes of the local coordinates (x, y, z) of the i-th plane are inclined at an angle θi in the YZ plane with respect to the absolute coordinate system (X, Y, Z).
Specifically, it is set as follows.

Z-axis: an angle θ that passes through the origin of the local coordinate system and is counterclockwise in the YZ plane with respect to the Z direction of the absolute coordinate system.
The straight line that makes i The y-axis: A straight line that passes through the origin of local coordinates and makes 90 ° counterclockwise in the YZ plane with respect to the z direction x-axis: The straight line that passes through the origin of local coordinates and is perpendicular to the YZ plane Di is a scalar representing the distance between the origins of the local coordinates of the i-th surface and the (i + 1) -th surface, and Ndi and νdi are the i-th surface and the (i +
1) The refractive index and Abbe number of the medium between surfaces.

In the embodiments of the present invention, a sectional view of the optical system and numerical data are shown.

The projection optical system 14 in the embodiment of the present invention has a rotationally asymmetric aspheric surface, and the shape is represented by the following equation.

A = (a + b) · (y ² · cos ² t + x ² ) B = 2a · b · cos t · [1 + {(ba) · y · sin t / 2a · b} + [ 1 + {(ba) ・ y
・ Sin t / (a ・ b)}-{y ² / (a ・ b)}-{4a ・ b ・ cos ² t + (a + b) ² sin ² t}
x ² / (4a ² b ² cos ² t)] ^1/2 ] as z = A / B + C ₀₂ y ² + C ₂₀ x ² + C ₀₃ y ³ + C ₂₁ x ² y + C ₀₄ y ⁴ + C ₂₂ x ² y ² + C ₄₀ x
⁴ + C ₀₅ y ⁵ + C ₂₃ x ² y ³ + C ₄₁ x ⁴ y + C ₀₆ y ⁶ + C ₂₄ x ² y ⁴ + C ₄₂ x ⁴ y ² + C ₆₀ x ⁶ The shape of each surface is a plane-based aspheric surface with a = b = ∞ and t = 0 in the above-mentioned curved surface equation, and by using only the even-order terms for x and setting the odd-order terms to 0, yz The plane has a plane-symmetrical shape with a plane of symmetry. Further, when the following condition is satisfied, the shape is symmetric with respect to the xz plane.

[0046] If the _{C 03 = C 21 = t =} 0 Furthermore _{C 02 = C 20 C 04 =} C 40 = C 22/2 is satisfied represents a rotation-symmetrical shape. If the above conditions are not satisfied, the shape is rotationally asymmetric.

Next, numerical data in an actual design example will be shown below. i Yi Zi θi Di N _di ν _di 1 0.0 0.0 0.0 4.0 1 Object surface 2 0.0 4.0 0.0 6.0 1.51633 64.1 Refraction surface 3 0.0 10.0 30.0 10.0 1.51633 64.1 Reflection surface 4 -8.66 5.0 10.0 5.0 1.51633 64.1 Reflection surface 5 -11.87 8.83- 40.0 200.0 1 Refraction surface 6 -111.87 182.03 40.0 0.0 1 Image surface Aspherical surface R2 surface C ₀₂ = -0.0212718806585 C ₀₃ = -0.045813982295 C ₀₄ = -0.00551370664075 C ₂₀ = 0.0877153319851 C ₂₁ = -0.0270000037123 C ₂₂ = -0.00612489531266 C ₄₀ = -0.0028415057482 R3 side C ₀₂ = -0.0207964845575 C ₀₃ = -0.00154795082493 C ₀₄ = 0.428577165554e-5 C ₂₀ = -0.0224664347515 C ₂₁ = -0.00127131383154 C ₂₂ = -0.847357732427e-4 C ₄₀ = -0.000103764314762 R4 side C ₀₂ = -0.00726889318095 C ₀₃ = -0.00019247906704 C ₀₄ = 0.426020737816e-4 C ₂₀ = -0.0189251975194 C ₂₁ = 0.00117691040772 C ₂₂ = 0.000205619140097 C ₄₀ = -0.352657125611e-4 R5 surface C ₀₂ = -0.0480342804996 C ₀₃ = 0.00209591712295 C ₀₄ = 0.000201242812139 _{C 20 = -0.046551482663 C 21 = 0.00634371846347} C 22 = -0.000729682057684 C 40 = -0.000286612648352 then imaging operation in the present embodiment It will be described.

The light beam from the image display panel 3 is incident on the incident surface R2 of the off-axial optical block 4, and is incident on the reflecting surface R2.
3. After being reflected in the order of the reflection surface R4, the light is emitted from the emission surface R5 to form an image on the screen 5. In the present embodiment, the screen 5 is not orthogonal to the reference axis of the light beam emitted from the emission surface R5. When the optical axis is not orthogonal to the screen as described above, and when the optical system is constituted by an optical surface rotationally symmetric with respect to the optical axis as in the related art, an ideal image without distortion and defocusing can be obtained. A plane perpendicular to the optical axis La as shown by a plane 6 in FIG.
In the screen 5, trapezoidal distortion and defocusing will occur.

FIG. 3A is a diagram showing the relationship between the image height H and the projection magnification β in a conventional optical system. The projection magnification on the screen is a central projection magnification β _{0 when the} image height H is positive.
When the image height H is negative, the opposite occurs. As a result, when a square image is input to the image display panel 3, the image formed on the screen 5 is as shown in FIG.
As shown by the solid line in (B), the shape becomes a trapezoidally distorted shape. It is to be noted that a broken line in the figure is an image without distortion. In order to correct this trapezoidal distortion, the present embodiment uses:
An optical design having a distortion D as shown in FIG.

FIGS. 4 and 5 show the object height (x) in this embodiment.
, Y) = (1, −1), (1, 0), (1, 1),
FIG. 4 is a spot diagram of light rays from (0, −1), (0, 0), and (0, 1), FIG. 4 is a spot diagram on the image evaluation surface 6, and FIG. That is, the broken lines in FIGS. 4 and 5 are projected images when a square is displayed on the image display panel 3. As shown in FIG. 4, by performing a design such that distortion occurs on the image evaluation surface 6, a projection image without distortion can be obtained on the screen 5.

FIG. 6 shows an aberration diagram on the image evaluation surface 6, and FIG. 7 shows an aberration diagram on the screen 5. FIG. 6 shows that the object heights (x, y) = (1, −1), (1, 0), (1,
1), (0, −1), (0, 0), and (0, 1) are lateral aberrations on the image evaluation surface 6. FIG. 7 shows that the object heights (x, y) = (1, −1), (1, 0),
These are lateral aberrations on the screen 5 corresponding to (1, 1), (0, -1), (0, 0), and (0, 1). 6 and 7, the right is the x section of the lateral aberration and the left is the y section of the lateral aberration.

As shown in the figure, by providing the image plane with the aberration of the inclination of the image plane on the image evaluation plane 6, a good projected image without defocus on the screen 5 can be obtained.

In the present embodiment, the second surface R2, the third surface R3, the fourth surface R4, and the fifth surface R5 are all off-axial optical surfaces whose surface normals do not coincide with the reference axes, and are each yz. This is a shape in which only a plane is a plane of symmetry in a broad sense. In addition,
In this specification, the term "broadly defined plane of symmetry"
"If the function describing the optical surface is infinitely differentiable inside all regions defined as real values, it is a symmetric surface defined for the entire region."
Is defined.

As an example, in an optical surface obtained by cutting out a part other than the vertex of the paraboloid, even if a symmetric surface cannot be found only for the cut out shape, the function defining the shape has a rotationally symmetric axis. Therefore, such an optical surface is considered to have countless planes including its rotational symmetry axis as a broadly defined symmetry plane.

Further, in this embodiment, all the reference axes including the incidence and emission of light are on the yz plane. The trapezoidal distortion and the image plane tilt are both asymmetrical with respect to the y-axis. Therefore, the off-axial optical surface is used to make the surface shape only the yz plane a broadly symmetric surface, and the surface is asymmetric with respect to the y-axis. 6 can be obtained.

Further, a compact projection optical system is realized by using the third surface R3 and the fourth surface R4 as reflection surfaces and bending the optical axis.

In this embodiment, the surfaces R2, R3,
R4 and R5 are integrally formed by a mold. By molding the off-axial optical surface with a mold in this way, mass productivity can be improved. In addition, since the plurality of optical surfaces are integrally formed, adjustment of the position between the optical surfaces is not required, and thus the assembly of the optical system is facilitated. In addition, by integrating them, a device with stable performance in which optical characteristics are hardly deteriorated due to environmental change or temporal change can be realized.

FIG. 8 is a schematic view of a main part of a projection type display apparatus according to a second embodiment of the present invention. In the present embodiment, the reflection type image information is projected on a screen surface by a projection optical system.

In FIG. 8, 7 is a light source, 8 is an illumination optical system, 9 is a Fresnel mirror, 10 is a translucent sheet (image information) placed on the Fresnel mirror 9, 11 is a projection optical system, and 12 is a screen. is there. The illumination optical system 8 is configured by arranging two off-axial optical blocks 15 and 16 facing each other. In the off-axial optical block 15, off-axial reflecting surfaces R7 and R9 are integrally formed by molding. The off-axial optical block 16
The off-axial reflecting surfaces R8 and R10 are integrally formed by molding.

The projection optical system 8 comprises an off-axial optical block 17, and the off-axial optical block 17 comprises an incident refracting surface R11, an exit refracting surface R16 and off-axial reflecting surfaces R12, R13, R14, R15. At the same time, these optical surfaces R1
1, R12, R13, R14, R15, and R16 are integrally formed. The broken line 13 indicates the reference axis in the present embodiment.

Light rays emitted from the light source 7 are reflected in the order of the off-axial reflecting surfaces R7, R8, R9, R10 and irradiate the translucent sheet 10. The light beam spatially modulated by passing through the translucent sheet 10 is reflected by the Fresnel mirror 9 and then enters the refraction surface R11, where it is reflected in the order of off-axial reflection surfaces R12, R13, R14 and R15. Then, the light exits from the refraction surface R16 and reaches the screen 12. As a result, the image of the translucent sheet 10 is
Projected above.

The optical axis of the light beam illuminating the translucent sheet 10 may not always be perpendicular to the translucent sheet 10 for design reasons. Also in this embodiment, in order to avoid interference between the illumination optical system 8 and the projection optical system 11, the optical axis of the light beam illuminating the translucent sheet 10 is
The layout is not vertical but tilted. Further, the optical axis in this embodiment, that is, FIG.
The reference axis 13 indicated by a broken line is
And neither of the screens 12 is vertical.

In such an arrangement, trapezoidal distortion and peripheral blurring have conventionally occurred in the projected image. In this embodiment, however, an off-axial curved surface is used for the projection optical system 11 to obtain a projected image without distortion and blurring. be able to. Therefore, the optical axis of the irradiation optical system 8 does not need to be perpendicular to the translucent sheet 10, and various layouts can be obtained.

In this embodiment, light rays are reflected off the off-axial reflecting surfaces R7, R8, R9 and R10.
That is, light rays enter the reflecting surface from the air side and exit to the air side. Since the optical system has a hollow structure as described above, it is possible to prevent the temperature of the optical system from being increased due to scattering and absorption of light in the optical path, so that the transmittance is high and the temporal change of the optical performance due to the temperature rise. A small number of optical systems can be obtained.

Further, in this embodiment, the light ray is internally reflected by the off-axial reflecting surfaces R12, R13, R14, R15, that is, the light beam is incident on the reflecting surface from the medium side and is emitted toward the medium side. With such a structure, the off-axial optical block including the refraction surfaces R11 and R16 can be integrated, a compact optical system can be obtained, and the adjustment process at the time of assembly can be simplified.

[0066]

According to the present invention, as described above, by utilizing the off-axial optical system, the projected image on the screen surface on which the image on the image display panel is arranged in an oblique direction is free from distortion and blur. It is possible to achieve a projection display device in which the entire optical system capable of performing projection while having optical performance is reduced in size.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a projection display device of the present invention.

FIG. 2 is an explanatory diagram of a coordinate system that defines configuration data of the projection display device of the present invention.

FIG. 3 is a diagram illustrating distortion correction in the projection display device of the present invention.

FIG. 4 is a spot diagram in the projection display device of the present invention.

FIG. 5 is a spot diagram in the projection display device of the present invention.

FIG. 6 is a lateral aberration diagram in the projection display device of the present invention.

FIG. 7 is a lateral aberration diagram in the projection display device of the present invention.

FIG. 8 is a diagram showing a configuration of a second embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a conventional projection display device.

FIG. 10 is a diagram illustrating trapezoidal distortion generated in a conventional example.

FIG. 11 is an aberration diagram in a conventional example.

FIG. 12 is a diagram illustrating trapezoidal distortion generated in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... Condenser lens 3 ... Image display panel 4 ... Off-axial optical block 5 ... Screen 7 ... Light source 8 ... Illumination optical system 9 ... Fresnel mirror 10 ... Translucent sheet 11 ... Projection optical system 12 ... Screen 13 ... Reference axis

Claims (10)

[Claims] 1. A projection display device for projecting an image on an image display panel onto a screen by a projection optical system,
A center line connecting the center of the image display panel and the center of the projected image is not perpendicular to at least one of the image display panel surface and the screen surface, and the projection optical system has an aspheric surface having 0 to 1 broadly defined symmetry plane. As a whole, at least one off-axial optical block having a refractive power capable of forming a real image including an off-axial surface having a shape as a constituent element is provided.
A projection display device comprising: 2. The projection display device according to claim 1, wherein said off-axial optical block includes at least one off-axial reflecting surface as a constituent element. 3. A projection display device for projecting an image on an image display panel onto a screen by a projection optical system,
A center line connecting the center of the image display panel and the center of the projected image is not perpendicular to at least one of the image display panel surface or the screen surface, and the projection optical system includes an off-axial reflection surface as a component and as a whole A projection type display device comprising at least one off-axial optical block having a refractive power capable of forming a real image. 4. A projection display device for converging a light beam from a light source by an illumination optical system, illuminating an image display panel with the light beam, and projecting an image on the image display panel onto a screen surface by a projection optical system. The center line connecting the center of the light source and the center of the image display panel is not perpendicular to the image display panel surface, and the illumination optical system includes an off-axial optical block having a refractive power including an off-axial reflection surface as a component. A projection display device comprising at least one. 5. The projection type display device according to claim 1, wherein said image display panel is a reflection type image display panel which spatially modulates the intensity of an incident light beam and reflects it. . 6. The projection type display device according to claim 2, wherein said off-axial reflecting surface is configured to reflect light rays incident from the air side to the air side. 7. The projection type display device according to claim 2, wherein said off-axial reflecting surface is configured to reflect a light beam incident from a medium side to the medium side. 8. The optical system according to claim 1, wherein said off-axial optical block is formed by molding.
8. The projection display device according to any one of claims 1 to 7. 9. The projection display device according to claim 8, wherein at least two of the plurality of optical surfaces constituting said off-axial optical block are integrally formed by molding. 10. An off-axial optical block, comprising: an incident surface on which a light beam is refracted and incident on a surface of a transparent body; a plurality of reflecting surfaces having a curvature for sequentially reflecting the incident light beam; The projection display device according to any one of claims 1 to 9, further comprising an optical element integrally formed with an exit surface for refracting and emitting the reflected light beam.