Radiation imagery chemistry: process – composition – or product th – Holographic process – composition – or product – Composition or product or process of making the same
Reexamination Certificate
1998-12-04
2002-12-10
Angebranndt, Martin (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Holographic process, composition, or product
Composition or product or process of making the same
C430S001000, C359S022000, C359S024000
Reexamination Certificate
active
06492065
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to space light modulating technology for use in a projector, display unit, printing and the like, and more particularly to a hologram color filter, production method of the hologram color filter and space light modulating apparatus using the hologram color filter.
2. Description of the Related Art
A space light modulating apparatus using the hologram color filter such as a color display unit has such an advantage in that its use efficiency of light is higher as compared to the color display unit using an ordinary color filter. For example, Japanese Patent Application Laid-Open No.2-500937 has disclosed a color display unit and method thereof using the hologram lens, in which the hologram lenses for red(R), green(G) and blue(B) are arranged horizontally in line in front of a stripe target such that they are disposed on multiple vertical stages so as to form each focal point on a target plane through each of the lenses thereby ensuring a high reading light efficiency.
Further, the Japanese Patent Application Laid-Open No.9-189809 (Japanese Patent Application No.7-315956) has disclosed a projection type display apparatus provided with a space light modulating unit which divides an incident light by diffraction to plural light beams having different wavelength bands as a color separating means and selectively collects light of each wavelength band at a picture element position of a corresponding color.
In the space light modulating unit employed in this conventional projection type display apparatus, its hologram color filter has such a characteristic that the diffraction efficiency of one polarized wave (hereinafter referred to as first polarized wave) of S polarized wave and P polarized wave with respect to a light impinging at a predetermined incident angle is kept substantially maximum while a difference of the diffraction efficiency between the first polarized wave and other polarized wave (hereinafter referred to as second polarized wave) is more than 30%. Of lights impinging upon this hologram color filter, the first polarized wave is diffracted by the hologram color filter and divided to spectrum, and then selectively converged to a picture element electrode position of a corresponding color on the liquid crystal display. The lights converged selectively to each picture element electrode is subjected to light modulation relating to video signal of a corresponding color, reflected and impinges again upon the hologram color filter. Then, the hologram color filter projects a polarized wave passing therethrough without being diffracted to a screen in an enlarged size.
A conventional space light modulating apparatus using the hologram color filter will be described more in detail with reference to FIG.
1
.
The hologram color filter
1
comprises three layers of a hologram lens
1
B for blue (B), a hologram lens
1
G for green (G) and a hologram lens
1
R for red (R). White light emitted from a xenon lamp or a metal-halide lamp (not shown) impinges upon the hologram lens
1
B of the top layer of the hologram color filter
1
. Here, only the B component is diffracted, and then focused and impinges upon the space light modulating element
3
constituted of a LCD panel by an operation of the lens. The G and R lights not diffracted by the hologram lens
1
B for B advance straight in the hologram lens
1
B for B and impinges upon the hologram lens
1
G for G. Then, only the G component is diffracted and focused and impinges upon the space light modulating element
3
by an operation of the lens. Then, the R light not diffracted by the hologram lens
1
G for G advances straight in the hologram lens
1
G for G and then impinges upon the hologram lens
1
R for R. Here, this light is diffracted and focused and impinges upon the space light modulating element
3
by an operation of the lens.
The space light modulating element
3
is constituted of a transparent electrode layer
4
, picture element electrode layer
5
and liquid crystal
6
which is disposed therebetween and sealed such that it is sandwiched by an orientation film (not shown). A plurality of the picture element electrode layers
5
are provided for each of R, G and B so that they are driven by the R, G, B picture element signals. Then, the B light converged by the hologram lens
1
B for B impinges upon the B picture element electrode
5
B. The G light converged by the hologram lens
1
G for G impinges upon the G picture element electrode
5
G. The R light converged by the hologram lens
1
R for R impinges upon the R picture element electrode
5
R.
A voltage corresponding to a picture element signal is applied between the picture element electrode layer
5
and transparent electrode layer
4
of the incident side. Polarization and modulation corresponding to an extent of this voltage are executed on the incident light by the liquid crystal
6
. For example, if a liquid crystal oriented vertically is used as the liquid crystal
6
, a portion corresponding to a picture element signal of light impinging as S wave component becomes P wave component. Light after modulation is reflected by the picture element electrode layer
5
(or dielectric material mirror) and impinges upon the hologram color filter
1
again. The P wave component of this light passes through the hologram color filter
1
as it is. As a result, it comes that only a component corresponding to the picture element is taken out. By projecting this transmission light onto a screen, a picture is displayed. Meanwhile, most of the S wave component of the light impinging upon the hologram color filter
1
again is diffracted again, advances in an opposite direction to the incident light and returns to a light source. By providing a polarizer allowing the P wave component to pass in the output light path as required, the S wave component passing through the hologram color filter
1
can be cut off.
Next, a production method of the hologram color filter having three layers will be described with reference to
FIGS. 2A-2D
. First, an EB lattice
7
constructed in the form of a concave lens by electron beam (EB) as shown in
FIG. 2A
is used. The EB lattice
7
has a lattice construction having continuously differing pitches corresponding to the lens. A plurality of the lattices
7
are provided continuously on the surface of the glass substrate
8
so that the EB master (exposure master)
9
is formed as shown in
FIG. 2B. A
layer of hologram recording material
11
is formed on the surface of the other glass substrate
10
appropriately such that the hologram recording material
11
is disposed so as to oppose the EB master
9
in a condition that it is in contact with the EB master
9
.
With this condition, exposure light
12
is irradiated from an exposure light source (not shown) at a predetermined angle as indicated by an arrow in FIG.
2
B. Consequently, as shown in
FIG. 2A
,
0
order light L
0
which advances straight and primary order light L
1
diffracted by the lattice are obtained. Although a small amount of higher order light are produced as the diffracted light depending on the case, this matter is omitted in a following description to facilitate understanding. Because the hologram recording material
11
is disposed below the EB master as described above, interference pattern between the
0
order light L
0
and primary order light L
1
is formed. As a result, a refractivity distribution similar to the interference pattern, or a hologram lens is formed on the hologram recording material
11
. As other production method, the reference light is used from an oblique direction as the
0
order light and the object wave is irradiated vertically as the primary order light so as to make both the lights interfere with each other.
To form a hologram color filter having three layers as shown in
FIG. 1
, first of all, the hologram recording material
11
is exposed by the EB master
9
for B so as to form a hologram lens
1
B for B. Next, as shown in
FIG. 2C
, the hologram recor
Imaoka Hirofumi
Nakagaki Shintaro
Shimizu Shigeo
Angebranndt Martin
Berkowitz Marvin C.
Nath Gary M.
Novick Harold L.
Victor Company of Japan , Limited
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