Head-mounted display apparatus comprising a rotationally asymmetric surface
First Claim
1. A head-mounted image display apparatus comprising:
- an image display device; and
an ocular optical system for leading an image formed by said image display device to an observer'"'"'s eyeball position without forming an intermediate image so that said image is observed as a virtual image,said ocular optical system including at least one reflecting surface having reflecting action,said at least one reflecting surface having a surface configuration defined by a plane-symmetry free form surface in a three-dimensional space which is a rotationally asymmetric surface, and which has only one plane of symmetry,a Z-axis is taken in a direction of prolongation of a line segment along which an axial principal ray from a center of an image display area of said image display device emanates from said ocular optical system and reaches a center of said observer'"'"'s eyeball position,a Y-axis is taken in a direction perpendicular to said Z-axis in a plane containing a folded line segment along which said axial principal ray is reflected by said reflecting surface, andan X-axis is taken in a direction perpendicular to both said Z- and Y-axes, and the following condition is satisfied;
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Accused Products
Abstract
A head-mounted image display apparatus capable of providing an observation image which is clear and has minimal distortion even at a wide field angle. The apparatus has an image display device (6), and an ocular optical system (7) for leading an image formed by the image display device (6) to an observer'"'"'s eyeball position without forming an intermediate image so that the image can be observed as a virtual image. The ocular optical system (7) has at least one reflecting surface (4) having reflecting action. The at least one reflecting surface (4) has a surface configuration defined by a plane-symmetry three-dimensional surface which has no axis of rotational symmetry in the surface nor out of the surface, and which has only one plane of symmetry.
99 Citations
32 Claims
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1. A head-mounted image display apparatus comprising:
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an image display device; and an ocular optical system for leading an image formed by said image display device to an observer'"'"'s eyeball position without forming an intermediate image so that said image is observed as a virtual image, said ocular optical system including at least one reflecting surface having reflecting action, said at least one reflecting surface having a surface configuration defined by a plane-symmetry free form surface in a three-dimensional space which is a rotationally asymmetric surface, and which has only one plane of symmetry, a Z-axis is taken in a direction of prolongation of a line segment along which an axial principal ray from a center of an image display area of said image display device emanates from said ocular optical system and reaches a center of said observer'"'"'s eyeball position, a Y-axis is taken in a direction perpendicular to said Z-axis in a plane containing a folded line segment along which said axial principal ray is reflected by said reflecting surface, and an X-axis is taken in a direction perpendicular to both said Z- and Y-axes, and the following condition is satisfied; - View Dependent Claims (6, 9, 10, 11, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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2. 14<
- D2 Y10<
5 (19-1)where D2 Y10 denotes a value determined by dividing D2 Y2 at a final reflecting surface of said ocular optical system as viewed in sequence of backward ray tracing in which light rays are traced from a pupil of said observer'"'"'s eyeball to said image display device by D2 Y2 at a first reflecting surface of said ocular optical system in the sequence of said backward ray tracing when an effective area is defined for each of said final and first reflecting surfaces as being an area formed by intersection of each reflecting surface and six principal rays, which are, with the Y-axis direction defined as a vertical direction, an axial principal ray in the Z-axis direction corresponding to a center of an image field, a principal ray in a field angle direction corresponding to a center of an upper edge of the image field, a principal ray in a field angle direction corresponding to an upper-right corner of the image field, a principal ray in a field angle direction corresponding to a center of a right-hand edge of the image field, a principal ray in a field angle direction corresponding to a lower-right corner of the image field, and a principal ray in a field angle direction corresponding to a center of a lower edge of the image field, and an equation which defines a configuration of each reflecting surface is differentiated twice in the effective area with respect to the Y-axis, which corresponds to a decentering direction of said surface, thereby obtaining second-order differential values D2 Y2, D2 Y1, D2 Y4, D2 Y5, D2 Y6, and D2 Y3 at points where said six principal rays strike said surface, respectively.
- D2 Y10<
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3. A head-mounted image display apparatus comprising:
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an image display device; and an ocular optical system for leading an image formed by said image display device to an observer'"'"'s eyeball position without forming an intermediate image so that said image is observed as a virtual image, said ocular optical system including at least one reflecting surface having reflecting action, said at least one reflecting surface having a surface configuration defined by a plane-symmetry free form surface in a three-dimensional space which is a rotationally asymmetric surface, and which has only one plane of symmetry, a Z-axis is taken in a direction of prolongation of a line segment along which an axial principal ray from a center of an image display area of said image display device emanates from said ocular optical system and reaches a center of said observer'"'"'s eyeball position, a Y-axis is taken in a direction perpendicular to said Z-axis in a plane containing a folded line segment along which said axial principal ray is reflected by said reflecting surface, an X-axis is taken in a direction perpendicular to both said Z- and Y-axes, and a final reflecting surface of said ocular optical system as viewed in sequence of backward ray tracing in which light rays are traced from a pupil of said observer'"'"'s eyeball to said image display device satisfies the following condition;
space="preserve" listing-type="equation">0.55<
D.sup.2 XY11<
4.0 (20-1)where D2 XY11 denotes a value of D2 X2/D2 Y2 when an effective area is defined for said final reflecting surface as being an area formed by intersection of said final reflecting surface and six principal rays, which are, with the Y-axis direction defined as a vertical direction, an axial principal ray in the Z-axis direction corresponding to a center of an image field, a principal ray in a field angle direction corresponding to a center of an upper edge of the image field, a principal ray in a field angle direction corresponding to an upper-right corner of the image field, a principal ray in a field angle direction corresponding to a center of a right-hand edge of the image field, a principal ray in a field angle direction corresponding to a lower-right corner of the image field, and a principal ray in a field angle direction corresponding to a center of a lower edge of the image field, and an equation which defines a configuration of said final reflecting surface is differentiated twice in the effective area with respect to the Y-axis, which corresponds to a decentering direction of said surface, thereby obtaining second-order differential values D2 Y2, D2 Y1, D2 Y4, D2 Y5, D2 Y6, and D2 Y3 at points where said six principal rays strike said surface, respectively, and further said equation is differentiated twice with respect to the X-axis, which corresponds to a direction perpendicular to said decentering direction, thereby obtaining second-order differential values D2 X2, D2 X1, D2 X4, D2 X5, D2 X6, and D2 X3 at the points where said six principal rays strike said surface, respectively.
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4. A head-mounted image display apparatus comprising:
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an image display device; and an ocular optical system for leading an image formed by said image display device to an observer'"'"'s eyeball position without forming an intermediate image so that said image is observed as a virtual image, said ocular optical system including at least one reflecting surface having reflecting action, said at least one reflecting surface having a surface configuration defined by a plane-symmetry free form surface in a three-dimensional space which is a rotationally asymmetric surface, and which has only one plane of symmetry, and wherein a final reflecting surface of said ocular optical system as viewed in sequence of backward ray tracing in which light rays are traced from a pupil of said observer'"'"'s eyeball to said image display device satisfies the following condition; - View Dependent Claims (7, 8)
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5. 3<
- CXY11<
4.0 (32-1)where CXY11 denotes a value of CX2/CY2 when an effective area is defined for said final reflecting surface as being an area formed by intersection of said final reflecting surface and six principal rays, which are, with the Y-axis direction defined as a vertical direction, an axial principal ray in the Z-axis direction corresponding to a center of an image field, a principal ray in a field angle direction corresponding to a center of an upper edge of the image field, a principal ray in a field angle direction corresponding to an upper-right corner of the image field, a principal ray in a field angle direction corresponding to a center of a right-hand edge of the image field, a principal ray in a field angle direction corresponding to a lower-right corner of the image field, and a principal ray in a field angle direction corresponding to a center of a lower edge of the image field, and curvatures in the X-axis direction, which corresponds to a direction perpendicular to a decentering direction of said final reflecting surface, are determined at points in said effective area at which said six principal rays strike said final reflecting surface from an equation which defines a configuration of said final reflecting surface as being CX2, CX1, CX4, CX5, CX6 and CX3, respectively, and further, curvatures at said points in the Y-axis direction, which corresponds to said decentering direction, are determined as being CY2, CY1, CY4, CY5, CY6 and CY3, respectively.
- CXY11<
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12. -0. 005<
- D2 Xmax5 <
0.005 (14-5)where D2 Xmax5 denotes values D2 X1-D2 X3 and D2 X4-D2 X6 at all reflecting surfaces of said ocular optical system when an effective area is defined for each of said reflecting surfaces as being an area formed by intersection of each reflecting surface and six principal rays, which are, with the Y-axis direction defined as a vertical direction, an axial principal ray in the Z-axis direction corresponding to a center of an image field, a principal ray in a field angle direction corresponding to a center of an upper edge of the image field, a principal ray in a field angle direction corresponding to an upper-right corner of the image field, a principal ray in a field angle direction corresponding to a center of a right-hand edge of the image field, a principal ray in a field angle direction corresponding to a lower-right comer of the image field, and a principal ray in a field angle direction corresponding to a center of a lower edge of the image field, and an equation which defines a configuration of each reflecting surface is differentiated twice in the effective area with respect to the X-axis, which corresponds to a direction perpendicular to a decentering direction of said surface, thereby obtaining second-order differential values D2 X2, D2 X1, D2 X4, D2 X5, D2 X6, and D2 X3 at points where said six principal rays strikes said surface, respectively. - View Dependent Claims (16)
- D2 Xmax5 <
Specification