1. A laminated thin film, comprising:
a substrate; and
at least two types of materials laminated on the substrate,
the laminated thin film has a transmittance of 95% or higher in a working wavelength band with respect to both P-polarized light and S-polarized light, and
the following expression (1) is satisfied with respect to a light ray of a specific wavelength \u03bb0 contained in the working wavelength band, and the following expressions (2) and (3) are always satisfied in a range of 0<\u03b8\u226615 degrees,
0.25
<
(
n
H
\xb7
d
H
+
n
L
\xb7
d
L
)
\u03bb
0
<
0.5
(
1
)
0.95
\u2264
\u0394
\u2061
(
\u03b8
)
A
\u2062
\u2062
sin
2
\u2062
\u03b8
\u2264
1.05
(
2
)
where
,
A
=
\u0394
\u2061
(
10
\u2062
\xb0
)
sin
2
\u2061
(
10
\u2062
\xb0
)
,
\uf603
\u0394
\u2061
(
10
\u2062
\xb0
)
\uf604
\u2265
2.0
\u2062
(
degrees
)
(
3
)
where an average film thickness of a material having relatively high refractive index nH is represented by dH, an average film thickness of a material having relatively low refractive index nL is represented by dL of the materials forming the laminated thin film, and a phase difference received by a light ray entering at an angle \u03b8 with respect to a normal of a surface of the laminated thin film is represented by \u0394(\u03b8).
2. A laminated thin film according to claim 1, wherein a film thickness ratio m expressed by the following equation is 0.43 or larger,
m=dH(dH+dL).
3. A laminated thin film according to claim 1, wherein the laminated thin film is formed on a flat surface.
4. A laminated thin film according to claim 1, wherein the laminated thin film is made of inorganic materials.
5. A phase plate comprising:
a substrate;
a one-dimensional periodical structure with a period that is a minimum wavelength or smaller in a working wavelength band in an in-plane direction of the substrate; and
a laminated thin film including at least two or more types of materials laminated on one another,
the following expression (1) is satisfied with respect to a light ray of a specific wavelength \u03bb0 contained in the working wavelength band, and the following expressions (5) and (6) are always satisfied in a range of 0<\u03b8\u226615 degrees;
0.25
<
(
n
H
\xb7
d
H
+
n
L
\xb7
d
L
)
\u03bb
0
<
0.5
(
1
)
0.95
\u2264
B
–
\u0394
\u2061
(
\u03b8
)
A
\u2062
\u2062
sin
2
\u2062
\u03b8
\u2264
1.05
\u2062
\u2062
where
(
5
)
A
=
B
–
\u0394
\u2061
(
10
\u2062
\xb0
)
sin
2
\u2061
(
10
\u2062
\xb0
)
,
\uf603
B
–
\u0394
\u2061
(
10
\u2062
\xb0
)
\uf604
\u2265
2.0
\u2062
(
degrees
)
,
B
=
\u0394
\u2061
(
0
\u2062
\xb0
)
(
6
)
where an average film thickness of a material having relatively high refractive index nH is represented by dH, an average film thickness of a material having relatively low refractive index nL, is represented by dL, of the materials forming the laminated thin film, and a phase difference received by a light ray entering at an angle \u03b8 with respect to a normal of a surface of the laminated thin film is represented by \u0394(\u03b8).
6. A phase plate according to claim 5, wherein the phase plate acts as a \xbc wavelength plate.
7. A phase plate according to claim 5, wherein a film thickness ratio m expressed by the following equation is 0.43 or larger,
m=dH(dH+dL).
8. A phase plate according to claim 5, wherein the phase plate is formed on a flat surface.
9. A phase plate according to claim 5, wherein the phase plate is made of inorganic materials.
10. A reflective liquid crystal display apparatus, comprising:
a light source;
a polarization beam splitter which transmits P-polarized light and reflects S-polarized light in illumination light emitted from the light source;
a reflection type liquid crystal display device which converts the illumination light into image light and reflects the image light;
a \xbc wavelength plate disposed between the polarization beam splitter and the reflection type liquid crystal display device;
the laminated thin film according to claim 1 disposed between the \xbc wavelength plate and the reflection type liquid crystal display device; and
a projection optical system which projects the image light, wherein:
the reflection type liquid crystal display device has positive refractive index anisotropy;
when a three-dimensional space is expressed by a c-axis representing a normal direction of a surface of the reflection type liquid crystal display device, a b-axis in a direction that is perpendicular to both a normal direction of a polarization separation surface of the polarization beam splitter and the c-axis, and an a-axis in a direction that is perpendicular to both the c-axis and the b-axis,
an optical axis direction of the reflection type liquid crystal display device in a black display state has a pretilt angle with respect to the c-axis;
both of normal directions of surfaces of the \xbc wavelength plate and the laminated thin film are parallel to the c-axis; and
an optical axis of the \xbc wavelength plate forms an angle of one of 0.5 to 5 degrees and \u22125 to \u22120.5 degrees with one of the a-axis and the b-axis.
11. A reflective liquid crystal display apparatus according to claim 10, wherein the polarization separation surface of the polarization beam splitter includes a form biregringence layer formed of a one-dimensional periodical structure with a period that is a minimum wavelength or smaller in a working wavelength band in a direction parallel to the polarization separation surface.
12. A reflective liquid crystal display apparatus, comprising:
a light source;
a polarization beam splitter which transmits P-polarized light and reflects S-polarized light in illumination light emitted from the light source;
a reflection type liquid crystal display device which converts the illumination light into image light and reflects the image light;
the phase plate according to claim 5 disposed between the polarization beam splitter and the reflection type liquid crystal display device; and
a projection optical system which projects the image light, wherein:
the reflection type liquid crystal display device has positive refractive index anisotropy;
when a three-dimensional space is expressed by a c-axis representing a normal direction of a surface of the reflection type liquid crystal display device, a b-axis in a direction that is perpendicular to both a normal direction of a polarization separation surface of the polarization beam splitter and the c-axis, and an a-axis in a direction that is perpendicular to both the c-axis and the b-axis;
an optical axis direction of the reflection type liquid crystal display device in a black display state has a pretilt angle with respect to the c-axis;
a normal direction of a surface of the phase plate is parallel to the c-axis; and
a periodic direction of the one-dimensional periodical structure of the phase plate forms an angle of one of 0.5 to 5 degrees and \u22125 to \u22120.5 degrees with one of the a-axis and the b-axis.
13. A reflective liquid crystal display apparatus according to claim 12, wherein the polarization separation surface of the polarization beam splitter includes a form biregringence layer formed of a one-dimensional periodical structure with a period that is a minimum wavelength or smaller in a working wavelength band in a direction parallel to the polarization separation surface.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A lens assembly comprising:
a first lens comprising a first optically active part, a first optically inactive part surrounding the first optically active part, and a first annular protrusion formed on the first optically inactive part, the first annular protrusion defining an accommodating room;
a second lens comprising a second optically active part, a second optically inactive part surrounding the second optically active part, a second annular protrusion formed on the second optically inactive part, and an annular light blocking layer formed on a surface of the second annular protrusion facing the first lens, the second annular protrusion being engaged in the first annular protrusion in such a manner that the second annular protrusion and the light blocking layer is received in the accommodating room to fix the first lens to the second lens.
2. The lens assembly of claim 1, wherein the second lens further comprises another annular light blocking layer formed on a surface of the second optically inactive part facing the first lens.
3. The lens assembly of claim 1, wherein a material of the light blocking layer is black ink.
4. The lens assembly of claim 1, wherein the black ink contains carbon black.
5. The lens assembly of claim 1, wherein a thickness of the light blocking layer is in approximate range from 1 micron to 100 microns.
6. The lens assembly of claim 1, wherein the first annular protrusion is formed on a surface of the first optically inactive part facing the second lens.
7. The lens assembly of claim 1, wherein the second annular protrusion is formed on a surface of the second optically inactive part facing the first lens.
8. The lens assembly of claim 1, wherein an inner surface of the first annular protrusion is in contact with an outer surface of the second annular protrusion.
9. The lens assembly of claim 1, wherein a surface of the first annular protrusion facing the second lens is in contact with a surface of the second optically inactive part facing the first lens.
10. The lens assembly of claim 1, wherein a surface of the light blocking layer facing the first lens is in contact with a surface of the first optically inactive part facing the second lens.
11. The lens assembly of claim 1, wherein the accommodating room is substantially cylindrical.
12. The lens assembly of claim 1, wherein the light blocking layer blocks light from the second optically inactive part and the second annular protrusion.
13. The lens assembly of claim 1, wherein the light blocking layer is formed by inkjet printing.
14. The lens assembly of claim 8, wherein the inner surface of the first annular protrusion is directly contact the outer surface of the second annular protrusion.
15. The lens assembly of claim 9, wherein the surface of the first annular protrusion facing the second lens is directly contact the surface of the second optically inactive part facing the first lens.
16. The lens assembly of claim 10, wherein the surface of the light blocking layer facing the first lens is directly contact with the surface of the first optically inactive part facing the second lens.