Stereoscopic image display apparatus
It is made possible to provide a stereoscopic image display apparatus capable of preventing the stereoscopic display characteristics from being degraded even if the locus of light rays between the lens and the two-dimensional display device becomes long. A stereoscopic image display apparatus includes: a plane display device having a display face formed of a plurality of pixels arranged in a matrix form; an optical plate comprising a plurality of lenses which are arranged in front of the display face of the plane display device and which have a uniaxial double refractive material inserted therein, and controlling light rays from the pixels; and a sheet polarizer provided between the plane display device and the optical plate to align a polarization direction of light ray. In the double refractive material, a maximum primary axis of refractive index is parallel to ridgelines of the lenses and is inclined in a direction opposed to a viewer.
1. A stereoscopic image display apparatus, comprising:
a plane display device having a display face formed of a plurality of pixels arranged in a matrix form;
an optical plate comprising a plurality of lenses which are arranged in front of the display face of the plane display device and which have a uniaxial double refractive material inserted therein, and controlling light rays from the pixels; and
a sheet polarizer provided between the plane display device and the optical plate to align a polarization direction of light ray,
wherein in the double refractive material, a maximum primary axis of refractive index is parallel to ridgelines of the lenses and is inclined in a direction opposed to a viewer; and
wherein in each of a plurality of lenses, lens faces have opposed convex shapes in opposite directions, 2θ denotes a viewing angle, s p denotes a sub-pixel pitch in a horizontal direction, m denotes a number of parallaxes in the horizontal direction, n lens denotes an average value of a refractive index of a medium located from a position corresponding to half of a length between tops of the convexo-convex lenses to the plane display device, r denotes a radius of curvature of both faces of the lenses, d denotes a thickness of lenses between tops of the lenses, N e denotes a refractive index in a maximum primary axis direction of the double refractive material formed inside the lenses, N o [[(<N e )]] which is less than N e denotes a refractive index in a minor axis direction perpendicular to the maximum primary axis direction, n denotes a refractive index of an isotropic substance formed outside the lens faces of the lenses, θ vert denotes a depression angle of a viewer with respect to a direction of the ridgeline of the lenses, θ tilt denotes an angle of inclination of the maximum primary axis direction to a direction opposed to the viewer, and θ real denotes an angle formed by a light ray which passes through the double refractive material and the maximum primary axis direction, and θ real is represented by the following expression
θ real =arccos(cos θ vert /N e )+θ tilt
and if a refractive index obtained when the light ray has passed through the double refractive material is represented by the following expression,
N
(
θ
real
)
=
N
e
N
o
N
e
2
sin
2
θ
real
+
N
o
2
cos
2
θ
real
the angle θ tilt satisfies the following condition
0.95
<
2
nr
2
N
(
θ
real
)
sin
(
arccos
(
cos
θ
vert
/
n
)
tan
θ
(
N
(
θ
real
)
-
n
)
(
2
N
(
θ
real
)
r
-
(
N
(
θ
real
)
-
n
)
d
)
s
p
m
<
1.05
.
2. The apparatus according to claim 1 , wherein an angle θ tilt by which the maximum primary axis direction of a molecule of the double refractive material is inclined to a direction opposed to the viewer is in a range of 7 to 10 degrees.
3. The apparatus according to claim 1 , wherein in the polarizer sheet, the polarization direction of the light ray is caused to coincide with the maximum primary axis of the refractive index of the double refractive material.
4. The apparatus according to claim 1 , further comprising a device which changes the polarization direction so as to display a three-dimensional image when the polarization direction is matched with the maximum primary axis and display a two-dimensional image when the polarization direction is matched with a direction perpendicular to the maximum primary axis.
5. A stereoscopic image display apparatus, comprising:
a plane display device having a display face formed of a plurality of pixels arranged in a matrix form;
an optical plate comprising a plurality of lenses which are arranged in front of the display face of the plane display device and which have a uniaxial double refractive material inserted therein, and controlling light rays from the pixels; and
a sheet polarizer provided between the plane display device and the optical plate to align a polarization direction of light ray,
wherein in the double refractive material, a maximum primary axis of refractive index is parallel to ridgelines of the lenses and is inclined in a direction opposed to a viewer; and
wherein in each of a plurality of lenses, one of lens faces has a convex shape on the viewer's side or has a convex shape on an opposite side of the viewer, 2θ denotes a viewing angle, s p denotes a sub-pixel pitch in a horizontal direction, m denotes a number of parallaxes in the horizontal direction, n lens denotes an average value of a refractive index of a medium located between a plane in contact with both ends of the lenses and the plane display device, r 1 denotes a radius of curvature of the lenses, d denotes a thickness of lenses, N e denotes a refractive index in the maximum primary axis direction of the double refractive material formed inside the lenses in a range from a surface of each of lenses to a plane in contact with both ends of each lens, N o [[(<N e )]] which is less than N e denotes a refractive index in a minor axis direction perpendicular to the maximum primary axis direction, n denotes a refractive index of an isotropic substance in contact with lens side of the lenses, θ vert denotes a depression angle of a viewer with respect to a direction of the ridgeline of the lenses, θ tilt denotes an angle of inclination of the maximum primary axis direction to a direction opposed to the viewer, θ real denotes an angle formed by a light ray which passes through the double refractive material and the maximum primary axis direction, θ real is represented by the following expression
θ real =arccos(cos θ vert /N e )+θ tilt
and if a refractive index obtained when the light ray has passed through the double refractive material is represented by the following expression,
N
(
θ
real
)
=
N
e
N
o
N
e
2
sin
2
θ
real
+
N
o
2
cos
2
θ
real
the angle θ tilt satisfies the following condition
0.95
<
2
nr
2
N
(
θ
real
)
sin
(
arccos
(
cos
θ
vert
/
n
)
tan
θ
(
N
(
θ
real
)
-
n
)
(
2
N
(
θ
real
)
r
-
(
N
(
θ
real
)
-
n
)
d
)
s
p
m
<
1.05
.
6. The apparatus according to claim 5 , wherein an angle θ tilt by which the maximum primary axis direction of a molecule of the double refractive material is inclined to a direction opposed to the viewer is in a range of 7 to 10 degrees.
7. The apparatus according to claim 5 , wherein in the polarizer sheet, the polarization direction is caused to coincide with the maximum primary axis of the refractive index of the double refractive material.
8. The apparatus according to claim 5 , further comprising a device which changes the polarization direction so as to display a three-dimensional image when the polarization direction is matched with the maximum primary axis and display a two-dimensional image when the polarization direction is matched with a direction perpendicular to the maximum primary axis.