JPH04109236A - Transmission screen, mold roll and stamper used for manufacturing the same, manufacturing method, and rear projection image display device using the screen - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transmission screen, a mold roll used for manufacturing the same, a stamper, a manufacturing method, and a rear projection type image display device using the screen. .

[Conventional technology]

Rear-projection television receivers, which use a projection lens to magnify the image displayed on a projection cathode ray tube as a small image source and project it onto a transmissive screen, have seen significant improvement in image quality in recent years, and the large screen is impressive. Because it allows users to enjoy a sense of realism, it is becoming more popular for both home and business use.

When using a projection cathode ray tube as an image source in a rear projection television receiver, in order to make the screen brightness sufficiently bright, conventionally, a cathode ray tube is used for each of the three primary colors of red, green, and blue. Generally, a configuration is used in which an image of three primary colors is synthesized on a screen by combining an image display and a projection lens.

In a rear projection television receiver with this configuration,
Conventionally, as described in Japanese Patent Application Laid-open No. 58-192022, for example, a transmissive screen has been generally constructed by combining a Fresnel lens sheet and a lenticular lens sheet in which light-scattering fine particles are dispersed. It is used.

FIG. 15 is a perspective view showing the main parts of the transmission type screen according to the above-mentioned prior art.

In the figure, 1 is a transmission screen, 2 is a Fresnel lens sheet placed on the image generation source (cathode ray tube screen) side, and 3 is a lenticular lens sheet placed on the viewing side. 20.30 are each Fresnel lens sheet 2
．． This is the base material of the lenticular lens sheet, and both are made of transparent thermoplastic resin. Among these, fine particles of a light diffusing material that scatters light are dispersed in the base material 30 of the lenticular lens sheet 3. 21 and 22 are the incident surfaces of the Fresnel lens sheet 2 for image light, respectively.

The exit surface 21 is a flat surface, and the exit surface 22 is a Fresnel convex lens surface.

Reference numeral 31 denotes an incident surface of the lenticular lens sheet 3, which has a shape in which lenticular lenses whose longitudinal direction is perpendicular to the screen are arranged in the horizontal direction of the screen. 32 is lenticular lens sheet 3
The lenticular lenses of the same shape are arranged substantially opposite to the lenticular lenses of the entrance surface 31, and a convex protrusion 33 is provided between adjacent lenticular lenses. A light absorbing layer (blank drive) 6 is laminated on this convex projection 33 .

In the conventional transmission screen described above, the light flux emitted from each point of the displayed image on the projection cathode ray tube surface passes through a projection lens (not shown) and enters the entrance surface 21 of the Fresnel lens sheet 2. At this time, Fresnel lens sheet 2
The above-mentioned incident light flux is converted into a substantially parallel light flux by the Fresnel lens constituting the exit surface 22 , and enters the lenticular lens sheet 3 .

The light beams incident on the lenticular lens sheet 3 are directed by the lenticular lenses constituting the incident surface 31 to a focal point near each lenticular lens surface on the exit surface 32, and are diffused in the horizontal direction of the screen from the focal point. The light is emitted toward the viewer in a form that is diffused in the vertical direction of the screen by the fine particles as a light diffusing material dispersed within the screen.

FIG. 16 is a cross-sectional view of the lenticular lens sheet 3 in the conventional transmission screen 1 described above.
Figure (a) is a vertical cross-sectional view at the center in the width direction of one lenticular lens constituting the exit surface 32, and Figure 16 (b).
) is a horizontal sectional view.

As shown in FIGS. 16(a) and 16(b), fine particles as a light diffusing material are dispersed in the base material 30 of the lenticular lens sheet 3, thereby preventing the incident light from entering the lens. After the light ray 14 enters from the incident surface 31, it moves in the horizontal direction,
The light propagates while being diffused in the vertical direction, and is emitted from the emission surface 32 toward the viewer in a mainly dispersed manner in the vertical direction. If the amount of the light diffusing material described above is increased, the light will be diffused over a wider angular range, broadening the directivity, and increasing the so-called viewing angle.

Here, the light rays passing through the lenticular lens sheet 3 are diffused in the horizontal direction depending on the lens shape of the incident surface of the lens sheet 3, and the light rays are diffused in the vertical direction by the action of the light diffusing material mentioned above. I would like to add something.

(RB to be Solved by the Invention) In the above conventional transmission screen, the light rays 14 incident on the entrance surface 31 of the lenticular lens sheet 30 are as shown in FIGS. 16(a) and 16(b). Since some of the light rays are scattered by the light diffusing material before reaching the focal point on the exit surface 32, some of the light rays may be reflected back to the incident surface or become stray light within the lenticular lens sheet 3.
Or it may be absorbed by the light absorption layer 6 (which is originally intended to absorb extraneous light to prevent contrast deterioration that would occur if the extraneous light is not absorbed), and the light emitted from the light absorption layer 6 may be absorbed. The focal point on surface 32 is not reached.

As a result, if the amount of light diffusing material included in the base material 30 of the lenticular lens sheet 3 is increased in order to widen the directivity in the vertical direction of the screen, the light loss will increase, the image will become extremely dark, and the contrast of the image will also decrease. There was a problem with the decline.

An object of the present invention is to solve the problems of the prior art described above, and to provide a transmissive type that can increase the amount of light diffusion in the vertical direction of the screen and broaden the directivity in the vertical direction of the screen without reducing the contrast of the image. It is an object of the present invention to provide a screen, and further to provide a mold roll, a stamper, a manufacturing method, and a rear projection type image display device using the screen.

[Means for Solving the Problems] In order to achieve the above object, in the transmission screen according to the present invention, the lenticular lens sheet is made of a transparent material as a base material, which is different from the conventional one. No light diffusing material is used, and instead, a large number of diffusion surfaces with valley-shaped cross-sections whose longitudinal direction is horizontal to the screen are provided on the exit surface of the lenticular lens sheet to diffuse light in the vertical direction of the screen. It was configured to do this.

In particular, in order to improve the contrast of the screen, in addition to the above configuration, on the exit surface of the lenticular lens sheet, the boundary between adjacent lenticular lenses on the entrance surface side is A convex protrusion with a finite width is formed at the boundary between adjacent lenticular lenses formed on the opposing areas or the exit surface, and a light absorption layer is provided on the convex protrusion to block external light. The structure uses the conventional contrast improvement measure of preventing contrast deterioration due to external light by absorbing it.

[Function] In a rear projection image display device using a transmission screen configured as described above, light emitted from an image generation source such as a projection cathode ray tube enters the screen through the projection lens, and is projected onto the front half of the screen. It passes through the Fresnel lens sheet that makes up the screen as parallel light without being diffused, and enters the lenticular lens sheet that makes up the rear half of the screen. At the same time, the light is diffused in the direction perpendicular to the screen screen and exits the lenticular lens sheet by a diffusion surface consisting of a notch with a valley-shaped cross section formed on the exit surface of the lenticular lens sheet. Therefore, the image light is not scattered while passing through the screen, and the screen image has good brightness and contrast characteristics.

In addition, when the conventional technology of providing a light absorption layer (black stripe) on the exit surface of the lenticular lens sheet is also used, when external light such as illumination light is incident on the exit surface of the pass-through screen, some of the incident light is Some of it will be absorbed in the light absorption layer and will not be reflected, so
The contrast of the image becomes even better when viewing the image in a bright place.

[Embodiment] FIG. 1 is a perspective view showing a transmission screen as an embodiment of the present invention.

In the figure, ■ is a transmission screen, 2 is a Fresnel lens sheet, and 3 is a lenticular lens sheet.

The Fresnel lens sheet 2 and the lenticular lens sheet 3 are fixed to each other at their respective ends (not shown). 20.30 are Fresnel lens sheets 2. This is the base material of the lenticular lens sheet 3, and all of them are made of a substantially transparent material.

Reference numeral 21 denotes the image light incident surface of the Fresnel lens sheet 2, which is a flat surface in this embodiment. Reference numeral 22 denotes the image light output surface of the Fresnel lens sheet 2, which is a Fresnel convex lens. Reference numeral 31 denotes an incident surface of the lenticular lens sheet 3, which has a shape in which lenticular lenses whose longitudinal direction is perpendicular to the screen are arranged in the horizontal direction of the screen. 32 is the output surface of the lenticular lens sheet 3, and lenticular lenses having similar shapes are arranged almost opposite to the lenticular lenses constituting the entrance surface 31, and furthermore, the surface of the lenticular lenses has a horizontal direction of the screen screen. The diffusion surface 4 of the cane has a valley-shaped cross-section in the longitudinal direction (for details, refer to i'
! -) are arranged in large numbers in the vertical direction of the screen at an arrangement pitch narrower than the arrangement pitch of the lenticular lenses in the horizontal direction of the screen. Further, on the exit surface 32, a convex protrusion 33 is formed between adjacent lenticular lenses, and a light absorption layer 6 is provided on the convex protrusion 33.

The difference between the embodiment of the present invention shown in FIG. 1 and the conventional transmission screen shown in FIG. The second point is that a notch-like diffusion surface 4 with a valley-shaped cross section is formed on the surface of the lenticular lens constituting the exit surface of the lenticular lens sheet 3.

Next, the functions of the Fresnel lens sheet 2 and the lenticular lens sheet 3 that constitute the transmission screen 1 shown in FIG. 1 will be explained.

FIG. 2 is a sectional view showing the main parts of a rear projection type image display device using the transmission screen 1 shown in FIG. 1, and FIG. FIG. 3 is a schematic development diagram when the optical system is developed on a horizontal plane.

In Figures 2 and 3, ■ is a transmission screen, 7
R, 70, and 7B are red, green, and blue projection cathode ray tubes, respectively; 8R, 8C; and 8B are projection cathode ray tubes 7R,
Projection lens for IG, 7B, 10R, IOC, 1, OB
are the red, green, and blue projected light fluxes, respectively. 11 is a projection light beam 10R, IOG.

This is a reflecting mirror for folding back the mirror 10B, and FIG. 3 is a developed view with this reflecting mirror 11 omitted.

Further, 12 is a housing, and 13R, 13G, and 13B are optical axes of projection lenses 8R, 80, and 8B, respectively, which intersect at a point SO near the center of the transmissive screen 1 at an optical axis concentration angle θ.

In Figures 2 and 3, the projection light flux 10R11, OG
, IOB enters the transmission screen 1 while expanding. Accordingly, when focusing on, for example, red light rays on the screen 1, the principal rays of each pixel are not parallel to each other, but enter the screen 1 in directions that are moving away from each other. At this time,
For each pixel on the screen 1, the direction of the principal ray of each pixel is the direction of the strongest light intensity, so for a viewer at a certain position, only a part of the image is bright, and the surrounding area is extremely bright. It will look dark.

In order to prevent this, in the transmission screen 1 shown in FIG. 1, the Fresnel lens sheet 2 makes the luminous flux of the image light incident on the entire incident surface 21 almost parallel luminous flux for each color of red, green, and blue. As such, it has a function of converting the light by the Fresnel convex lens of the output surface 22 and making it enter the lenticular lens sheet 3, thereby improving the brightness distribution of the screen.

On the other hand, the lenticular lens sheet 3 has a function of diffusing the luminous flux of the image light emitted from the Fresnel lens sheet 2 in the horizontal and vertical directions for each pixel and emitting it toward the viewer. At this time, the lenticular lens array on the entrance surface 31 of the lenticular lens sheet 3 is
The image light is diffused in the horizontal direction of the screen screen (this point is the same in the conventional technology), and the diffusion surface 4 of the lenticular lens surface of the exit surface 32 has a valley-shaped cross-sectional shape.
performs vertical diffusion of the screen (this point is
This is different from the conventional technology, which uses light diffusing materials dispersed within the base material 30).

FIG. 4 is a cross-sectional view of the lenticular lens sheet 3 of the transmission screen 1 in FIG. 1, and FIG.
4(b) is a vertical sectional view at the center of one lenticular lens of the exit surface 32 (located in the vertical direction of the screen), FIG. 4(b) is a horizontal sectional view at the AA section of FIG. (C) is a horizontal sectional view taken along the BB section of FIG. 4(a).

In FIG. 4(a) and FIG. 4(c), 4 is the exit surface 3
This is a notch-like diffusion surface with a valley-shaped cross section provided on the surface of the lenticular lens 2, and the incident light 14 from the projection cathode ray tube, which is the image generation source, hits each part of the diffusion surface at an incident angle of 60 or more. The light is incident and totally reflected, and then the totally reflected light is incident on another diffusing surface, refracted, and emitted, so that it is completely diffused in the vertical direction of the screen, and the desired directivity in the vertical direction of the screen is achieved. Designed to provide directional characteristics. Figure 4(a) shows that the diffusion surface 4 has a valley-shaped notch in cross section.
will be looked after by.

Here, when the refractive index of the base material 30 of the lenticular lens sheet 3 is, for example, 1.49, the above critical angle θC is. At this time, if the incident light ray 14 is once totally reflected by the diffusing surface 4 and then incident on another diffusing surface 4, if the incident angle is smaller than the above-mentioned critical angle, it will not be totally reflected but will be refracted and directed toward the viewer. Emits light.

On the other hand, in FIG. 4(b), the incident surface 31 of the lenticular lens sheet 3 is approximately an elliptical cylindrical surface (that is, a lenticular lens), and the incident light ray 14 is directed to the exit surface 3.
The light once converges at a focal point F on the screen 2, and is emitted from that focal point so as to be diffused in the horizontal direction of the screen. At this time, the elliptical cylindrical surface of the entrance surface 31 is designed so as to obtain desired directional characteristics in the horizontal direction of the screen.

Incidentally, the alignment pinch of the notch-like diffusion surface 4 having a valley-shaped cross section of the lenticular lens sheet 3 shown in FIG. It is necessary to determine this by taking into consideration moiré with the annular pitch of the Fresnel convex lens of the Fresnel lens sheet.

Of these, moiré due to the pitch of the scanning lines and the pitch of the notched diffusion surface 4 requires attention, but the pitch of the notched diffusion surface 4 should be made sufficiently smaller than the pinch in the horizontal direction of the screen of the lenticular lens. If it is designed so that the scanning line pinch and the pitch of the notch-like diffusion surfaces 4 do not have a simple integer ratio, the moiré intensity will be at a level that does not pose a practical problem.

For example, the screen size is 800m horizontally.
m, 600 mm in the vertical direction, and the pinch in the horizontal direction of the transmissive screen is 0.78 mm, the screen has 450 mm.
Assuming that horizontal scanning lines of a book are displayed, the pitch of the scanning lines is 1.33 mm, the annular pitch of the Fresnel convex lens is 0.105 m, and the notch-shaped diffusing surface 4
If the pinch is selected to be about 0.29 mm, moiré will be much less noticeable.

Now, the lenticular lens sheet 3 of this embodiment shown in FIGS. 1 and 4(a) to 4(C) has a 15th
Unlike the case of the lenticular lens sheet 3 of the conventional transmission type screen 1 shown in FIG.

Therefore, a part of the light rays is not reflected back to the incident surface by the light diffusing material, becomes stray light within the lenticular lens sheet 3, or is absorbed by the light absorption layer 6, and the incident light rays 14 are not lost. It reaches a focal point on the exit surface 32. When expanding the directivity in the vertical direction of the screen, it is sufficient to simply change the shape of the diffusion surface 4, which has a valley-shaped cross-section and no light loss due to the light diffusion material.
The effect is that even if the directional characteristics are expanded, the brightness and contrast of the screen will not deteriorate much.

Next, a method for manufacturing the lenticular lens sheet 3 of the transmission screen 1 as an embodiment of the present invention shown in FIG. 1 will be described.

FIG. 5 is a schematic diagram of a manufacturing apparatus for the lenticular lens sheet 3, in which 41 is an extruder, 42 is a sheet molding goug, and 43 is a transparent thermoplastic resin sheet serving as the base material of the lenticular lens sheet 30. Reference numerals 44 and 45 designate first and second mold rolls, each having a matrix having the shape of the entrance surface of the lenticular lens sheet 3 and a matrix having the shape of the exit surface. 46 is a take-up roll, and 47 is a cutter.

6 is an enlarged perspective view of a mold roll used in the manufacturing apparatus shown in FIG. 5, FIG. 6(a) is a perspective view showing the first mold roll 44, and FIG. ) is a perspective view showing the second mold roll 45.

In manufacturing the lenticular lens sheet 3 of this example, first, a pellet of transparent thermoplastic resin material is prepared. This resin material includes acrylic resin, vinyl chloride resin, polyvinyl chloride resin, polyester resin,
Cellulose acetate resin, styrene resin, acrylonitrile-butadiene-styrene copolymer resin, polycarbonate resin, etc. can be used, but the resin is not limited to these.

Next, this pellet of resin material is supplied to an extruder 41, and the extruder 41 discharges a transparent resin sheet 43 through a sheet-forming die 42. When this resin sheet 43 is in a semi-molten state before being cooled and solidified, or when the resin sheet 43 is once cooled and then reheated, the resin sheet 4
3 is passed between the first mold roll 44 and the second mold roll 450, and the shape of the entrance surface and the shape of the exit surface of the lenticular lens sheet 3 are simultaneously formed.

Further, the resin sheet is taken up by a take-up roll 46 and cut into a predetermined size by a cutter 47.

Convex projection 3 on the exit surface of the lenticular lens sheet 3
The light absorption layer 6 on the layer 3 may be laminated by a known method such as screen printing before or after cutting with the cutter 47 described above.

According to the above manufacturing method, a lenticular lens sheet that does not contain a light diffusing material and therefore has no scattering of image light due to the light diffusing material (it has the effect of manufacturing a lenticular lens sheet with good image brightness and contrast with high productivity).

In the above manufacturing method, the shape of the entrance surface and the shape of the exit surface of the lenticular lens sheet are formed using the mold rolls 44° and 45. It is also possible to manufacture using a stamper. In this case, the sheet of transparent thermoplastic resin may be heated and pressed using a mold stamper using a general press device. At this time, the shape of the mold stamper is such that the matrix of the entrance surface shape and the exit surface shape of the lenticular lens sheet in the mold roll shown in FIGS. 6(a) and 6(b) is flattened. It has a stretched-out shape.

The manufacturing method using the above-mentioned mold stamper also has the effect of manufacturing lenticular lens sheets with high productivity that do not contain a light diffusing material and therefore have good image brightness and contrast without scattering of image light by the light diffusing material. .

Next, another embodiment of the present invention will be described.

7 to 12 are sectional views of the lenticular lens sheet 3 in other embodiments of the transmission screen according to the present invention, and are similar to FIG. 4.

In FIGS. 7 to 12, the same parts as in FIG. 4 are designated by the same reference numerals, and their explanations will be omitted.

The difference between the lenticular lens sheet 3 shown in FIG. 7 and the lenticular lens sheet 3 shown in FIG. 4 is that in FIG. While the surface is a concave, almost ellipsoidal cylindrical surface, in FIG. . This is shown in Figure 7 (C).
This is expressed by the curve S1 shown in FIG.

The transmissive screen according to this embodiment has a feature that not only the directional characteristics in the vertical direction of the screen but also the directional characteristics in the horizontal direction of the screen can be changed by the shape of the diffusion surface 4 having a cross-sectional shape of a perfume cut. Regarding the brightness and contrast of the image, effects similar to those of the embodiment shown in FIG. 4 are obtained.

In the lenticular lens sheet 3 as another embodiment of the present invention shown in FIG. 8, similarly to the lenticular lens sheet 3 shown in FIG. Almost ellipsoidal surface concave on the air side (
(see curve S2 in FIG. 8(C)). In the transmission type screen according to this embodiment, as in the case of the previous embodiment, not only the directional characteristics in the vertical direction of the screen screen but also the directional characteristics in the horizontal direction of the screen are determined by the cross-sectional shape of the diffuser surface 4, which has the shape of a slit for perfume. There are characteristics that can be changed depending on the The same effects as in the embodiment shown in FIG. 4 can be obtained regarding the brightness and contrast of the image.

In a lenticular lens sheet 3 as still another embodiment of the present invention shown in FIG. 9, the diffusion surface 4 having a slit-like cross-sectional shape is a substantially elliptical cylindrical surface convex toward the air side from which light is emitted. There is.

The transmissive screen according to this embodiment has a characteristic that the directivity characteristic in the vertical direction of the screen exhibits a characteristic that the base is considerably widened. Regarding the brightness and contrast of the image, the same effects as in the embodiment shown in FIG. 4 are obtained.

In a lenticular lens sheet 3 as yet another embodiment of the present invention shown in FIG. Part (W) of (a) is
It does not have a clear ridgeline, but is rounded.

In the lenticular lens sheet 3 in this embodiment,
Lenticular lens surface and notched diffusion surface 4 during manufacturing
This has the effect of making it difficult for chipping to occur at the boundary between the two parts. Furthermore, the same effects as in the embodiment shown in FIG. 4 can be obtained regarding the brightness and contrast of the image.

In a lenticular lens sheet 3 as still another embodiment of the present invention shown in FIG. 11, the shape of the diffusion surface 4 having a slit-like cross-section of aromatic wood is a substantially elliptical cylindrical surface convex toward the air side from which light is emitted. , has a shape in which a concave, almost elliptical cylindrical surface is connected to the air side from which light is emitted.

The transmission screen according to this embodiment also has the same effect as the embodiment shown in FIG. 4.

In the lenticular lens sheet 3 as a further embodiment of the present invention shown in FIG. The sides are concave, making it vertically asymmetrical.

The transmission screen according to this embodiment has the advantage that the directivity characteristics in the vertical direction of the screen can be made vertically asymmetrical. Furthermore, the same effects as in the embodiment shown in FIG. 4 can be obtained regarding the brightness and contrast of the image.

In each of the embodiments described above, the diffusion surface 4 in the cross-sectional shape of aromatic wood in the exit surface 32 of the lenticular lens sheet 3 is provided on the lenticular lens surface between the convex protrusions 33. However, the space between the convex projections 33 does not necessarily have to be a lenticular lens surface, and may be a flat surface.

In this case, the red,
Although the color balance of the three primary colors of green and blue changes slightly depending on the position of the viewer, the directivity in the vertical direction of the screen by providing the cut-shaped diffusion surface is similar to the above example. Similar properties are obtained. Furthermore, the same effects as in the above embodiments can be obtained regarding the brightness and contrast of images.

Further, in each of the above embodiments, the light absorption layer 6 is provided on the convex protrusion 33, but this light absorption layer 6 has the effect of suppressing a decrease in image contrast due to reflection of external light such as illumination light. As I mentioned earlier, there are certain words. Therefore, if the convex protrusion 33 and the light absorption layer 6 are not provided, the contrast of the image will decrease slightly when external light is reflected, but the directivity in the vertical direction of the screen due to the provision of the cut-like diffusion surface As a result, characteristics similar to those of the above embodiment can be obtained.

Furthermore, in each of the above embodiments, the structure is such that no light diffusing material is included inside the lenticular lens 30 base material 30, but a small amount of light diffusing material is mixed in to finely adjust the directivity in the vertical direction of the screen. You may.

In this case, as long as the diffusion of light in the vertical direction of the screen is dominated by the diffusion by the cut-like diffusion surface, the same effects as in each of the above embodiments can be obtained.

FIG. 13 is a perspective view showing still another embodiment of the transmission screen according to the present invention. Also, Fig. 14 shows the 13th
14(a) is a vertical sectional view at the center of one lenticular lens on the exit surface 32 (A in FIG. 13).

14(b) is a horizontal sectional view (A direction sectional view).
B, a sectional view in the B direction of the figure).

In FIGS. 13 and 14, the same parts as in FIGS. 1, 7, and 4 are designated by the same reference numerals, and their explanations will be omitted.

The difference between the transmissive screen 1 of the embodiment shown in FIG. 13 and the transmissive screen 1 of FIG.
The longitudinal direction of the lenticular lens on the entrance surface 31 of the lenticular lens sheet 30 is perpendicular to the screen screen,
The longitudinal direction of the cut-shaped diffusion surface of the exit surface 32 is the horizontal direction of the screen, whereas in FIG. 13, the longitudinal direction of the lenticular lens on the entrance surface 31 of the lenticular sheet 3 is the horizontal direction of the screen. The point is that the longitudinal direction of the notch-like diffusion surface on the output surface 32 is perpendicular to the screen. Therefore, in the embodiment shown in FIG. 13, the lenticular lens on the entrance surface 31 of the lenticular sheet 3 diffuses the light in the vertical direction of the screen, and the cut-shaped diffusion surface 4 of the exit surface 32 diffuses the light in the horizontal direction of the screen. be done.

In this embodiment as well, a small amount of light diffusing material may be mixed into the lenticular lens sheet, but as long as the diffusion of light in the horizontal direction of the screen is dominated by the diffusion by the cut-like diffusion surface, There are effects similar to those of each of the above embodiments.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, light emitted from an image generation source such as a projection type cathode ray tube is incident on the screen via the projection lens, and the Fresnel lens sheet and lenticular lens that constitute the screen are used. Among the sheets, the Fresnel lens sheet does not diffuse the light (but it is diffused in the horizontal direction of the screen by the lenticular lens array that forms the entrance surface of the lenticular lens sheet, and the light that is provided on the lenticular lens that forms the exit surface) The light is diffused in the vertical direction of the screen by the slit-like diffusion surface of the aromatic wood cross-section.

Therefore, even if the directivity in the vertical direction of the screen is wide, the image light is not scattered, and the brightness and contrast characteristics of the image are improved.

Furthermore, by combining the conventional technology of providing a convex projection between adjacent lenticular lenses on the exit surface of the lenticular lens sheet and providing a light absorption layer thereon, the exit surface of the transmissive screen is illuminated. When external light such as light enters, some of the incident light is absorbed by the light absorption layer and is not reflected, so the contrast of the image is even better when viewing the image in a bright place. It has the effect of becoming something.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a transmission screen according to the present invention, FIG. 2 is a sectional view showing the configuration of a rear projection type image display device using a transmission screen, and FIG. 3 is a rear projection type image display device. FIG. 4 is a cross-sectional view of the lenticular lens sheet of the transmission screen shown in FIG. 1, and FIG. FIG. 6 is a schematic perspective view of a mold roll used in the manufacturing device shown in FIG. Cross-sectional view of lens sheet,
Fig. 13 is a perspective view showing another embodiment of the transmissive screen of the present invention, Fig. 14 is a sectional view of the lenticular lens sheet of the transmissive screen shown in Fig. 13, and Fig. 15 is a conventional transmissive screen. FIG. 16 is a perspective view showing the first
FIG. 6 is a cross-sectional view of the lenticular lens sheet of the conventional transmission screen shown in FIG. 5; Explanation of symbols 1... Transmissive screen, 2... Fresnel lens sheet, 3... Lenticular lens sheet, 20°3
0...Base material, 21.31...Incidence surface, 22.32.
... Output surface, 33... Convex protrusion, 4... Notch-like diffusion surface, 6... Light absorption layer, 7R, 7G, 7B...
Projection type cathode ray tube, 8R, 8G, 8f3... Projection lens, 9G... Coupler, 11... Reflector, 12... Housing, 41... Extruder, 42... Sheet molding die for,
44...First mold roll, 45...Second mold roll, 46...Take-up roll, 47...Cutter representative Patent attorney Akio Namiki No. 22 Fig. 4 (α) Figure 7 (α) Fill 8 Figure fa) Ward 9 (α) Figure 11 (OJ) (b) (C) 1!10 Figure (a) Figure 12 (cL)

Claims (1)

[Claims] 1. In a transmission screen configured with a Fresnel lens sheet placed on the image generation source side and a lenticular lens sheet placed on the image viewing side, from the lenticular lens sheet to the viewing side. When the diffusion of transmitted image light is divided into diffusion in the vertical direction of the screen and diffusion in the horizontal direction of the screen, either of the two types of diffusion has diffusion characteristics that depend on the shape of the light exit surface of the lenticular lens sheet. A transparent screen characterized by: 2. In the transmission screen according to claim 1, the light entrance surface of the lenticular lens sheet has a lens shape in which lenticular lenses are continuously arranged, and the light exit surface of the lenticular lens sheet constitutes the entrance surface. A transmission screen characterized by adopting a shape in which a large number of notch-like diffusion surfaces with a valley-shaped cross section are arranged, the longitudinal direction of which is a direction that intersects with the longitudinal direction of a lenticular lens shape. 3. In the transmissive screen according to claim 1, the lenticular lens sheet is made of a substantially transparent material as a base material, and the light incident surface of the lenticular lens sheet is a lenticular lens whose longitudinal direction is perpendicular to the screen. The lenses are arranged continuously in the horizontal direction of the screen, and the light exit surface of the lenticular lens sheet has a number of slit-shaped diffusing surfaces with a valley-shaped cross section whose longitudinal direction is the horizontal direction of the screen. shape, and on the light exit surface of the lenticular lens sheet,
A convex protrusion having a constant width is disposed in a region facing the boundary between lenticular lenses that are continuously arranged in the horizontal direction of the screen screen on the light incident surface, and A transmission type screen characterized by forming a light absorption layer on. 4. In the transmissive screen according to claim 1, the lenticular lens sheet is made of a substantially transparent material as a base material, and the light incident surface of the lenticular lens sheet is a lenticular lens whose longitudinal direction is perpendicular to the screen. The lens is arranged continuously in the horizontal direction of the screen, and the light exit surface of the lenticular lens sheet has lenticular lenses arranged continuously in the horizontal direction of the screen, with the longitudinal direction being perpendicular to the screen. The surface of the lenticular lens constituting the light exit surface of the lenticular lens sheet has a shape in which a large number of slit-like diffusion surfaces with a valley-shaped cross section are arranged with the horizontal direction of the screen as the longitudinal direction. A transparent screen featuring 5. In the transmissive screen according to claim 1, the lenticular lens sheet is constructed using a substantially transparent material as a base material, and the light incident surface of the lenticular lens sheet is a lenticular lens whose longitudinal direction is perpendicular to the screen surface. The lens is arranged continuously in the horizontal direction of the screen, and the light exit surface of the lenticular lens sheet has lenticular lenses arranged continuously in the horizontal direction of the screen, with the longitudinal direction being perpendicular to the screen. forming a convex protrusion of a certain width at the boundary between the lenticular lenses which are arranged in a continuous manner and forming a light absorption layer thereon; and a light absorption layer is formed thereon; A transmission type screen characterized in that the surface of the lenticular lens constituting the surface has a shape in which a large number of notch-like diffusion surfaces having a valley-shaped cross section are arranged with the horizontal direction of the screen screen being the longitudinal direction. 6. In a transmission type screen constituted by a Fresnel lens sheet placed on the image generation side and a lenticular lens sheet placed on the image viewing side, the light incident surface of the lenticular lens sheet continuously passes through the lenticular lens. When it is assumed that the transmitted image light diffused from the lenticular lens sheet to the viewing side is diffused in the vertical direction of the screen screen and the horizontal direction of the screen screen, the transmitted image light is diffused in the horizontal direction of the screen screen. The light incident surface of the lenticular lens sheet mainly contributes to the lenticular lens sheet, and the light exit surface of the lenticular lens sheet has a cross section whose longitudinal direction is a direction intersecting the longitudinal direction of the lenticular lens shape constituting the incident surface. A transmission screen characterized in that it is formed in a shape with a large number of valley-shaped diffusion surfaces disposed, and the light exit surface of the lenticular lens sheet contributes to diffusing the transmitted image light in the vertical direction. . 7. In the transmission screen according to any one of claims 2 to 6, the arrangement pitch of the lenticular lenses on the light incidence surface of the lenticular lens sheet is greater than the arrangement pitch of the lenticular lenses on the light exit surface of the lenticular lens sheet. A transmission screen characterized by a small arrangement pitch of valley-shaped cuts in cross section. 8. The transmission screen according to any one of claims 2 to 7, wherein two slopes forming the valley shape in the cut of the valley shape in cross section on the light exit surface of the lenticular lens sheet. A transmission screen characterized in that at least one of the screens has a concave shape toward the air side from which light is emitted. 9. In the transmission screen according to any one of claims 2 to 7, two slopes forming the valley shape in the cut of the valley shape in cross section on the light exit surface of the lenticular lens sheet. A transmission type screen characterized in that at least one of the screens has a convex shape toward the air side from which light is emitted. 10. A mold roll having a matrix having the shape of the light exit surface of the lenticular lens sheet in the transmission screen according to any one of claims 2 to 9. 11. A mold stamper comprising a matrix having the shape of the light exit surface of the lenticular lens sheet in the transmission screen according to any one of claims 2 to 9. 12. The method for manufacturing the lenticular lens sheet in a transmission screen according to any one of claims 2 to 9, comprising: a mold roll having a matrix having a shape of a light incident surface of the lenticular lens sheet; By passing a thermoplastic resin sheet as a material of the lenticular lens sheet to be manufactured between the mold roll according to item 10, the shape of the entrance surface and the shape of the exit surface are simultaneously imparted to the thermoplastic resin sheet. A method for manufacturing a lenticular lens sheet, comprising a step of shaping. 13. The method for manufacturing the lenticular lens sheet in a transmission screen according to any one of claims 2 to 9, comprising: a mold stamper having a matrix having a shape of a light incident surface of the lenticular lens sheet; By sandwiching a thermoplastic resin sheet as a material of the lenticular lens sheet to be manufactured between the mold stamper described in item 11, the shape of the entrance surface and the shape of the exit surface are simultaneously imparted to the thermoplastic resin sheet. A method for manufacturing a lenticular lens sheet, comprising a step of shaping. 14. A rear projection type image display device using the transmission screen according to any one of claims 1 to 9.