U.S. patent application number 10/208929 was filed with the patent office on 2003-02-13 for fresnel lens sheet and transmission type projection screen.
Invention is credited to Honda, Makoto, Ide, Michihisa, Sekiguchi, Hiroshi.
Application Number | 20030030903 10/208929 |
Document ID | / |
Family ID | 19070772 |
Filed Date | 2003-02-13 |
United States Patent
Application |
20030030903 |
Kind Code |
A1 |
Honda, Makoto ; et
al. |
February 13, 2003 |
Fresnel lens sheet and transmission type projection screen
Abstract
A Fresnel lens sheet comprises a Fresnel lens on one surface
thereof, wherein respective unit surfaces constructing the Fresnel
lens sheet have rough surfaces. Since it has a rough surface, it
enables suppressing the occurrence of moire, when making up a
screen. The other Fresnel lens sheet comprises a Fresnel lens on
one surface thereof, and a fly-eye lens or prisms as a regular
concavities and convexities configuration for suppressing regular
reflection on the surface thereof on a side opposite to the side
having the Fresnel lens formed thereon. Since it has on its rear
surface a fly-eye lens or a prism, it enables suppressing the
occurrence of ghost image.
Inventors: |
Honda, Makoto; (Tokyo,
JP) ; Ide, Michihisa; (Tokyo, JP) ; Sekiguchi,
Hiroshi; (Tokyo, JP) |
Correspondence
Address: |
WILDMAN, HARROLD, ALLEN & DIXON
225 WEST WACKER DRIVE
CHICAGO
IL
60606
US
|
Family ID: |
19070772 |
Appl. No.: |
10/208929 |
Filed: |
July 31, 2002 |
Current U.S.
Class: |
359/457 |
Current CPC
Class: |
G03B 21/625
20130101 |
Class at
Publication: |
359/457 |
International
Class: |
G03B 021/60 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 8, 2001 |
JP |
2001-240112 |
Claims
What is claimed is:
1. A Fresnel lens sheet comprising a Fresnel lens on one surface
thereof, wherein respective unit surfaces constructing the Fresnel
lens sheet have rough surfaces.
2. A Fresnel lens sheet according to claim 1, wherein the
arithmetic average roughness (Ra) of the rough surfaces is 0.2
.mu.m or more.
3. A Fresnel lens sheet according to claim 1, further comprising a
regular concavities and convexities configuration for suppressing
regular reflection on the surface thereof on a side opposite to the
side having the Fresnel lens.
4. A Fresnel lens sheet according to claim 3, wherein the regular
concavities and convexities configuration is made up of a
lenticular lens, a fly-eye lens, or prism.
5. A Fresnel lens sheet comprising a Fresnel lens on one surface,
thereof, and a fly-eye lens or prisms as a regular concavities and
convexities configuration for suppressing regular reflection on the
surface thereof on a side opposite to the side having the Fresnel
lens formed thereon.
6. A transmission type projection screen comprising a Fresnel lens
sheet and a lenticular lens sheet, wherein the Fresnel lens sheet
comprises a Fresnel lens on one surface thereof, respective unit
surfaces of the Fresnel lens sheet having rough surfaces, and the
lenticular lens sheet is disposed on a side having the Fresnel lens
location of the Fresnel lens sheet.
7. A transmission type projection screen according to claim 6,
wherein the lenticular lens sheet has a lenticular lens on a side
thereof having the location of the Fresnel lens sheet and has a
light-shading layer on the surface, corresponding to a
non-condensing part of the lenticular lens, located on a side
thereof opposite to the side having the location of the Fresnel
lens sheet.
8. A transmission type projection screen according to claim 6,
wherein the lenticular lens sheet has lenticular lenses on a side
having the location of the Fresnel lens sheet; and the respective
surfaces of the unit lenticular lenses is provided with a
light-absorbing layer made of a transparent colored layer.
9. A transmission type projection screen comprising a Fresnel lens
sheet and a lenticular lens sheet, wherein the Fresnel lens sheet
comprises a Fresnel lens on one surface thereof, and a fly-eye lens
or prisms as a regular concavities and convexities configuration
for suppressing regular reflection on the surface thereof on a side
opposite to the side having the Fresnel lens formed thereon, and
wherein the lenticular lens sheet is disposed on a side having the
Fresnel lens location of the Fresnel lens sheet.
10. A transmission type projection screen according to claim 9,
wherein the lenticular lens sheet has a lenticular lens on a side
thereof having the location of the Fresnel lens sheet and has a
light-shading layer on the surface, corresponding to a
non-condensing part of the lenticular lens, located on a side
thereof opposite to the side having the location of the Fresnel
lens sheet.
11. A transmission type projection screen according to claim 9,
wherein the lenticular lens sheet has lenticular lenses on a side
having the location of the Fresnel lens sheet; and the respective
surfaces of the unit lenticular lenses is provided with a
light-absorbing layer made of a transparent colored layer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an improved transmission
type screen which is used in the so-called projection type
television having a projector and a screen accommodated in one
cabinet and makes it possible to view a clear image with no ghost
image or moire following the image, and a Fresnel lens sheet used
therein.
[0003] 2. Description of the Related Art
[0004] As a television whose viewing screen size is large, there is
the so-called projection type television wherein an image is
projected from a rear surface thereof and is watched or viewed from
a front surface.
[0005] As illustrated in FIGS. 5A and 5B, a conventional projection
type television 31 is the one wherein a screen 101 is fitted to a
bored window portion at the upper part of its front surface of a
cabinet 10; a projector 2 is disposed at a lower position of the
interior thereof; and a mirror 3 for making small the depth of the
cabinet 10 is disposed at the upper position of its rear surface.
Each of these members is disposed in the way of having a positional
relationship which permits the projection light 4 from the
projector 2 to be reflected by the mirror 3 and projected onto the
screen 101, and is received within the same cabinet and fixed. It
is to be noted that, for clarifying the interior of the cabinet 10,
in each of the illustrations, the side surfaces are removed.
[0006] As a screen 101 in the conventional projection type
television 31 there is used the one in which, as illustrated in
FIG. 6, a Fresnel lens sheet 111 is disposed on the rear surface
side, and a lenticular lens sheet 121 is disposed on the watching,
or viewing, side, in the way in which the both are located close to
each other.
[0007] The lenticular lens sheet 121, as one example, has on the
rear surface side, i.e. the Fresnel lens sheet 111 side a
lenticular lens 122 configured in the way in which a lot of unit
lenticular lenses are arrayed so that the direction of the groove
defined between each two of the unit lenticular lenses may be in
coincidence with the vertical direction of the screen. It has on
the viewing side of the lenticular lens sheet 121 and at the
position corresponding to a non-condensing portion of the
lenticular lens 122 of the rear surface side a light-shading, layer
123 for preventing the reflection of a light having entered from
the viewing side.
[0008] The Fresnel lens sheet 111, as one example, has a Fresnel
lens 112 on the viewing side, i.e. the lenticular lens sheet 121
side and has a flat surface 114 on the rear surface side, i.e. the
projecting side.
[0009] As illustrated in FIG. 7, when a projection light 4 is
projected from the rear surface onto the Fresnel lens sheet 111 in
the above-described screen 101, this projection light 4 transmits
through the Fresnel lens sheet 111 and, in addition, other than
this, a reflected light 4a occurs upon the rear surface of the
Fresnel lens sheet 111. As illustrated in FIG. 5B, the reflected
light 4a reflected by the rear surface of the Fresnel lens sheet
111 is reflected again by the mirror 3 and thereafter enters the
screen 101 again. Since this incident light enters the screen at a
position different from the initial incident position of the
projection light 4, a ghost image occurs at the shifted position in
addition to the original image to become a cause of the so-called
"ghost".
[0010] Especially, the shorter the length of the optical path
between the projector 2 and the screen 101, i.e. the projection
distance is, or/and, the shorter the distance between the screen
101 and the mirror 3 is, the more likely to occur the ghost is.
[0011] Various kinds of attempts for dissolving the occurrence of
ghost have heretofore also been made. According to, among them, the
attempt to form an anti-reflection layer on the rear surface of the
screen by deposition, or the like, it is indeed possible to weaken
the intensity of the ghost but it is impossible to dissolve the
ghost. Also, performing deposition with respect to the rear surface
of the individual screen results in the poor manufacturing
efficiency and so cannot be said to be a technique suitable from
the industrial point of view.
[0012] Further, in Japanese Patent Application Laid-Open No.
5-158153, the technique is disclosed of providing on the rear
surface of the Fresnel lens sheet a configuration of concavities
and convexities such as satin, hair line, or lenticular lens and,
in this case, providing especially a horizontal lenticular lens
configured to get the direction of the grooves oriented in the
horizontal direction. By this technique, also, it discloses that
such ghost problem can be solved. However, when the lenticular lens
sheet is combined with the Fresnel lens sheet, the drawback occurs
that, as a result of the lenticular lens being added to the rear
surface of the Fresnel lens sheet, the occurrence of moire is
furthered.
SUMMARY OF THE INVENTION
[0013] It is an object of the present invention to provide a
transmission type projection screen which, in a projection type
television, enables preventing the occurrence of a ghost image due
to the reflected light resulting from the reflection of a
projection light from the rear surface of the screen and which has
a good productivity of the elements to be added for prevention of
the above mentioned ghost image, or, adding such elements does not
newly further the production of moire, and a Fresnel lens sheet for
use therein.
[0014] As a result of having studied how to more improve an image
on the projection type television, it has become possible to attain
the above-described object by forming a regular concavities and
convexities configuration on the rear surface of the Fresnel lens
sheet, or making the Fresnel lens side of the Fresnel lens sheet a
rough surface in addition to forming such regular concavities and
convexities configuration on the rear surface thereof.
[0015] According to a first aspect of the present invention, there
is provided a Fresnel lens sheet comprising a Fresnel lens on one
surface thereof, wherein respective unit surfaces constructing the
Fresnel lens sheet have rough surfaces.
[0016] A second aspect of the present invention provides a Fresnel
lens sheet according to the first aspect, wherein the arithmetic
average roughness (Ra) of the rough surfaces is 0.2 .mu.m or
more.
[0017] A third aspect of the present invention provides a Fresnel
lens sheet according to the first or second aspect, further
comprising a regular concavities and convexities configuration for
suppressing regular reflection on the surface thereof on a side
opposite to the side having the Fresnel lens.
[0018] A fourth aspect of the present invention provides a Fresnel
lens sheet according to the third aspect, wherein the regular
concavities and convexities configuration is made up of a
lenticular lens, a fly-eye lens, or prism.
[0019] According to a fifth aspect of the present invention, there
is provided a Fresnel lens sheet comprising a Fresnel lens on one
surface thereof, and a fly-eye lens or prisms as a regular
concavities and convexities configuration for suppressing regular
reflection on the surface thereof on a side opposite to the side
having the Fresnel lens formed thereon.
[0020] According to a sixth aspect of the present invention, there
is provided a transmission type projection screen wherein a
lenticular lens sheet is disposed on a side having the Fresnel lens
location of the Fresnel lens sheet according to any one of the
above described first to fifth aspects.
[0021] A seventh aspect of the present invention provides a
transmission type projection screen according to the sixth aspect,
wherein the lenticular lens sheet has a lenticular lens on a side
thereof having the location of the Fresnel lens sheet and has a
light-shading layer on the surface, corresponding to a
non-condensing part of the lenticular lens, located on a side
thereof opposite to the side having the location of the Fresnel
lens sheet.
[0022] An eighth aspect of the present invention provides a
transmission type projection screen according to the sixth aspect,
wherein the lenticular lens sheet has lenticular lenses on a side
having the location of the Fresnel lens sheet; and the respective
surfaces of the unit lenticular lenses is provided with a
light-absorbing layer made of a transparent colored layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIGS. 1A and 1B are views each illustrating a screen
according to the present invention;
[0024] FIGS. 2A and 2B are views each illustrating a Fresnel lens
sheet according to the present invention;
[0025] FIGS. 3A and 3A', 3B and 3B', and 3C and 3C' are views each
pair of that illustrates the configuration of concavities and
convexities on a rear surface of the Fresnel lens sheet;
[0026] FIGS. 4A and 4B are views each illustrating the reflection
made by the rear surface of the Fresnel lens sheet;
[0027] FIGS. 5A and 5B are views each illustrating a projection
type television;
[0028] FIG. 6 is a view illustrating a conventional screen; and
[0029] FIG. 7 is a view illustrating the reflection made by the
rear surface of a conventional Fresnel lens.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] As illustrated in FIG. 1, a transmission type projection
screen 1 according to the present invention is the one in which a
Fresnel lens 11 located on the rear surface side and a lenticular
lens 21 on the viewing side are disposed in the way they are close
to each other. As far as this is concerned, the projection screen 1
according to the present invention is the same as that in the prior
art. Therefore, the projection screen according to the present
invention can be used as a replacement of the conventional screen
101 in the projection type television 31 explained in conjunction
with FIG. 5.
[0031] As illustrated in FIG. 1A, a lenticular lens sheet 21 in the
transmission type projection screen 1 according to the present
invention may have the same structure, explained previously, as
that in the conventional case. Namely, it has a lenticular lens 22
on the rear surface side of the lenticular lens sheet 21. And, on
the viewing side of the lenticular lens sheet 21, it has, at a
position corresponding to a non-condensing portion of the rear
surface side lenticular lens 22, a light-shading layer 23 for
preventing the reflection of light that has entered from the
viewing side.
[0032] Alternatively, as illustrated in FIG. 1B, a lenticular lens
sheet 21' may have a lenticular lens 22 on the rear surface side
and, on the surface of this lenticular lens, it may have a light
absorbing layer 22a made of a transparent colored layer. In
general, when the projector is a liquid crystal panel, it is likely
that moire may occur between the liquid crystal panel and the
lenticular lens. Therefore, it is necessary to make the pitch of
the lenticular lens small to thereby avoid the occurrence of such
moire. However, in this case, the manufacture of such a lenticular
lens becomes difficult to perform. For this reason, when forming
the lenticular lens sheet 21', the method can be adopted of
performing two-layer extrusion of colorless transparent resin
(which can contain therein a light diffusion agent) and transparent
colored resin, or inserting a colored film into a forming die and
thereby laminating it on the lenticular lens along the
configuration thereof, or performing otherwise. Namely, the light
absorbing layer 22a may be the one which has been formed in those
ways. The light transmitting through the light absorbing layer 22a
from the rear surface side simply transmits, for the most part,
through the light absorbing layer 22a. Regarding the external light
that has gotten incident upon the screen from the viewing side, the
distance over which it passes through the interior of the light
absorbing layer 22a becomes long by total reflection and therefore
the proportion in which the light is absorbed increases. Therefore,
the contrast of the image increases.
[0033] The lenticular lens 22 may be the one which is integral with
the lenticular lens sheet 21 or 21', or the one which is obtained
by laminating the lenticular lens 22 onto a base member sheet as a
separate resin layer. Regarding the configuration thereof, also, it
may be the one whose cross section is circular, elliptic, or
other.
[0034] Regarding the Fresnel lens sheet 11, although it is the same
as the conventional one in that it has a Fresnel lens 12 on the
viewing side, it is different from the latter one in that the
respective unit surfaces constructing the Fresnel lens are in the
form of rough surfaces 12a. Also, in an example illustrated in
FIGS. 1A/1B and 2A/2B, especially a sectional view in FIG. 2B, in
the respect, as well, that the rear surface of the Fresnel lens
sheet 11 has a regular concavities and convexities configuration
13, the Fresnel lens sheet 11 is different from the conventional
one.
[0035] As the regular concavities and convexities configuration 13
on the rear surface of the Fresnel lens sheet 11, a lenticular
lens, especially a horizontal lenticular lens wherein unit
lenticular lenses are arrayed so that the direction in which the
grooves are formed may be the horizontal direction is preferable.
FIG. 3A is a rear surface view of the Fresnel lens sheet 11 in
which the regular concavities and convexities configuration is the
horizontal lenticular lens 13a and FIG. 3A' is a longitudinal
sectional view of it.
[0036] When using the horizontal lenticular lens array 13a as the
regular concavities and convexities configuration on the rear
surface of the Fresnel lens sheet 11, the projection light which
has entered is reflected to become a reflected light with less
directionality over a vertical-directional wide range. Therefore,
the proportion of re-reflection by the mirror is decreased, with
the result that the re-entry of the incident light that causes the
ghost image is decreased very much. Also, since the incident light
is vertically diffused due to the action of the horizontal
lenticular lenses 13a, if the screen has the lenticular lens sheet
diffusing the projection light only in the horizontal direction,
the screen is generally endowed with the merit that enables
widening the range within which the image can be visually
recognized in the vertical direction.
[0037] Incidentally, it the lenticular lens serving as the regular
concavities and convexities configuration is used solely for the
purpose of preventing the occurrence of the ghost image, respective
unit lenses of this lenticular lens may be disposed not
horizontally but vertically or slantwise.
[0038] As the regular concavities and convexities configuration 13
on the rear surface of the Fresnel lens sheet 11, it may be the
so-called fly-eye lens wherein isotropic or anisotropic unit lenses
are arrayed in the form of a matrix wherein, for example, they are
arrayed vertically and laterally. FIG. 3B is a rear surface view of
the Fresnel lens sheet 11 whose regular concavities and convexities
configuration is a fly-eye lens 13b while FIG. 3B' is a perspective
view of the rear surface of that sheet 11.
[0039] When using the fly-eye lens 13b, the incident light is
reflected over a wide range including the horizontal direction and
vertical direction and, in addition, the horizontal and vertical
visually recognizable range of the screen can be controlled.
[0040] As the regular concavities and convexities configuration 13
on the rear surface of the Fresnel lens sheet 11, it may be the one
wherein prism members are arrayed, especially wherein they have
grooves in the horizontal direction and can reflect the incident
light in the up-and-down direction. FIG. 3C is a rear surface view
of the Fresnel lens sheet wherein the regular concavities and
convexities configuration is constructed of prism members 13c while
FIG. 3C' is a longitudinal sectional view of the prism members. The
prism members in these figures are the ones wherein, as in the case
of the horizontal lenticular lens illustrated in FIG. 3A, the prism
members whose individual cross sections are triangular respectively
are disposed so that the groove formed when the prism members have
been arrayed each other may extend in the horizontal direction.
[0041] In a case where such prism members 13c are disposed on the
rear surface of the Fresnel lens sheet, the projection light that
has entered a prescribed one of the arrayed prism members is
reflected in a prescribed direction. Therefore, it is preferable to
adjust the angle of each surface of the prism member in advance so
that, after the reflected light has again been reflected by the
mirror, this reflected light does not enter the screen.
[0042] By the Fresnel lens sheet 11 being equipped with the regular
concavities and convexities configuration 13a, 13b, or 13c such as
that illustrated in FIG. 3A, 3B, or 3C, in contrast to the
conventional technique wherein the rear surface of the Fresnel lens
sheet 11 is a flat surface and therefore the projection light 4 is
regularly reflected in the directions indicated in broken lines in
FIG. 4, the invention enables the projection light 4 to be
reflected according to the surface configuration of the regular
concavities and convexities configuration 13 and as a result this
light becomes reflected light rays oriented in various directions.
Therefore, since the regular reflection that occurs when the rear
surface is a flat surface is suppressed, the occurrence of the
phenomenon that the projection light thereafter is again reflected
by the mirror and re-enters the rear surface of the Fresnel lens
sheet 11 is suppressed and this can prevent the appearance of the
ghost image.
[0043] In the present invention, in a case where making the
respective unit surfaces constructing the Fresnel lens 12 of the
Fresnel lens sheet 11 rough surfaces, when having constructed the
screen by combining it with the lenticular lens sheet, that
concavo-convex configuration of the Fresnel lens 12 becomes
difficult to see when watching the screen via the lenticular lens
sheet 21. Therefore, it becomes difficult for interference to occur
between the Fresnel lens 12 and the lenticular lens 22. As a
result, it is possible to suppress the occurrence of moire.
[0044] Also, in a case, as well, where having the regular
concavities and convexities configuration 13 on the rear surface of
the Fresnel lens sheet 12, that concavities and convexities
configuration 13 becomes difficult to see from the Fresnel lens 12
side, or the viewing side of the lenticular lens sheet 21.
Therefore, it becomes unlikely that interference occurs between or
among the regular concavities and convexities configuration 13,
Fresnel lens 12, and lenticular lens 22. This also can lead to
suppressing the occurrence of moire.
[0045] As the surface roughness of the rough surfaces 12a of this
Fresnel lens, preferably, it is 0.2 .mu.m or more in terms of the
arithmetic average roughness (Ra). when the arithmetic average
roughness (Ra) is smaller than 0.2 .mu.m, the above-described
effect that the Fresnel lens 12 or regular concavities and
convexities configuration 13 becomes difficult to see weakens with
the result that moire becomes outstanding. On the other hand, when
the arithmetic average roughness (Ra) becomes excessively large, it
has an undesirable effect upon the refraction property of the
Fresnel lens and therefore it is preferable that the roughness (Ra)
be 100 .mu.m or less.
[0046] The rough surface 12a of the Fresnel lens can also be
obtained by roughening each of the respective unit surfaces
constructing the Fresnel lens 12 which are made into smooth
surfaces beforehand. However, ordinarily, the rough surface 12a is
obtained by having previously roughened the die surface of a die
for forming the Fresnel lens by sand blast, beads blast, chemical
etching, etc. and forming the Fresnel lens sheet 11 with the use of
such die.
[0047] According to the present invention as described in the first
aspect, since the Fresnel lens has a rough surface, it is possible
to provide a Fresnel lens sheet which, when making up a screen by
using the Fresnel lens, enables suppressing the occurrence of moire
attributable to the configuration of the Fresnel lens sheet.
[0048] According to the present invention as described in the
second aspect, in addition to the effect of the invention as
described in the first aspect, since the arithmetic average
roughness of the rough surfaces has been defined, it is possible to
provide a Fresnel lens sheet which enables more reliably
suppressing the occurrence of moire attributable to the
configuration of the Fresnel lens sheet.
[0049] According to the present invention as described in the third
aspect, in addition to the effect of the invention as described in
the first or second aspect, since the Fresnel lens sheet has been
formed in the way of having the regular concavities and convexities
configuration on its rear surface, it is possible to provide a
Fresnel lens sheet which enables suppressing the occurrence of
ghost image due to the reflection of the projection light by that
rear surface.
[0050] According to the present invention as described in the
fourth aspect, in addition to the effect of the invention as
described in the third aspect, since the regular concavities and
convexities configuration has been specifically defined, it is
possible to provide a Fresnel lens sheet which enables reliably
performing the formation of the regular concavities and convexities
configuration.
[0051] According to the present invention as described in the fifth
asepct, since the Fresnel lens sheet has on its rear surface a
fly-eye lens or a prism, it is possible to provide a Fresnel lens
sheet which enables suppressing the occurrence of ghost image due
to the reflection of the projection light by that rear surface.
[0052] According to the present invention as described in the sixth
asepct, it is possible to provide a transmission type projection
screen capable of exhibiting the effect of the Fresnel lens sheet
according to the invention as described in any one of the first to
fifth aspects, by combining it with the lenticular lens sheet.
[0053] According to the present invention as described in the
seventh aspect, in addition to the effect of the invention as
described in the sixth aspect, since the lenticular lens sheet has
been made the one having a light-shading layer, it is possible to
provide a transmission type projection screen capable of
suppressing the reflection of external light from the viewing
side.
[0054] According to the present invention as described in the
eighth aspect, in addition to the effect of the invention as
described in the sixth aspect, since the lenticular lens sheet has
been formed in the way of having a light-absorbing layer on its
light-incident side, it is possible to provide a transmission type
projection screen in which the occurrence of moire is less; and
especially even when performing projection using a liquid crystal
projector, the occurrence of moire is less.
EXAMPLE
[0055] Taking up concrete manufactured examples, that the
occurrence of ghost image and moire has been prevented is shown
below. It is to be noted that the reference symbols in the
explanation made below are used from within FIG. 1 or 5.
Manufactured Example 1
[0056] Various relevant values of the projection type television 31
were set as follows. The viewing screen size of the screen 1: 1270
mm (50 inch type), the projection distance: 870 mm, the distance
from the center of the screen 1 to the center of the mirror 3: 390
mm, and the angle of inclination of the mirror 3 (the angle
indicated by .theta. in FIG. 5B: 35.degree. from the vertical
line.
[0057] As the Fresnel lens sheet 11, there was manufactured the one
which had on one side a Fresnel (convex) lens 12 with the pitch:
0126 mm, the focal distance: 800 mm and the arithmetic average
roughness (Ra) of respective unit surfaces of the obverse surface:
0.26 .mu.m, and which had on the opposite side surface a horizontal
lenticular lens 13a with the lens pitch: 0.09 mm and the cross
section: part of a circle having a diameter of 0.2 mm, the
horizontal lenticular lenses 13a being densely arrayed and thereby
made into the regular concavities and convexities configuration,
and which had the thickness of 2 mm.
[0058] As the lenticular lens sheet 21' there was manufactured the
one which contained therein a diffusion agent in its interior and
which had on one side a (vertical) lenticular lens 22 with the lens
pitch: 0.161 mm, the cross section: part of a circle having a
diameter of 0.87 mm, the lenticular lens 22 having provided thereon
a light absorbing layer with the thickness 20 .mu.m, the light
absorbance: 40% and the thickness: 1 mm by an extrusion molding
method using an acrylic resin.
Manufactured Example 2
[0059] Various relevant values of the projection type television 31
were made the same as in the manufactured example 1.
[0060] As the Fresnel lens sheet 11, there was manufactured the one
which had on one side a Fresnel (convex) lens 12 with the pitch:
0.16 mm, the focal distance: 800 mm and the arithmetic average
roughness (Ra) of respective unit surfaces of the obverse surface:
0.35 .mu.m, and which had on the opposite side surface a horizontal
lenticular lens array 13a with the lens pitch: 0.114 mm, the cross
section: part of a circle having a diameter of 0.3 m, the
horizontal lenticular lenses 13a being densely arrayed and thereby
made into the regular concavities and convexities configuration,
and which had the thickness of 2 mm.
[0061] As the lenticular lens sheet 21, there was manufactured, the
one which contained therein a diffusion agent in its interior and
which had on one side a (vertical) lenticular lens 22 with the lens
pitch: 0.24 mm, the cross section: part of a circle having a
diameter of 0.13 mm, the lenticular lens 22 having provided on the
surface corresponding to its non-condensing portion a black stripe
with the width: 0.15 mm, and the thickness: 0.34 mm by an extrusion
molding method using an acrylic resin.
[0062] The Fresnel lens sheet 11 and lenticular lens sheet 21'
manufactured in the manufactured example 1, and the Fresnel lens
sheet 11 and lenticular lens sheet 21 manufactured in the
manufactured example 2, were, each, arranged to overlap each other
so that the Fresnel lens 12 and the lenticular lens 22 may face
each other, to thereby make up a screen 1. Then, using a liquid
crystal projector 2 having 500 ANSI lumens (the ANSI lumen is a
unit representing the lightness of the liquid crystal projector),
projection was performed to the screen 1 from the horizontal
lenticular lens array 13a side of the Fresnel lens sheet 11.
[0063] In the screen of either the manufactured example 1 or the
manufactured example 2, when projection was performed, no ghost
image attributable to the reflection by the rear surface of the
screen occurred and a clear image could be viewed. In addition,
moire attributable to the existence of the horizontal lenticular
lens on the rear surface of the Fresnel lens sheet 11 did not
occur, either. However, when using the screen in which the
arithmetic average roughness (Ra) of the respective unit surfaces
on the Fresnel lens 12 surface was 0.17 .mu.m and the other
relevant values of which were the same as in the manufactured
example 1, although no ghost image occurred, radial moire was
viewed.
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