JPH09318801A - Plane type lens and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the generation of moire interference fringes, improve diffusion so as to expand a visual angle and to obtain a plane lens having a high contrast and image quality by constituting this lend of many spherular transparent beads fixed to a colored hot melt adhesive layer on the light incident side surface of a transparent base material. SOLUTION: This plane type lend is composed of the transparent base material 11, the colored hot melt adhesive layer 12 formed on the light incident side surface of the transparent base material 11 and the many spherular transparent beads 13 consisting of one layer fixed to this colored hot melt adhesive layer 12. Such plane type lend 10 is obtd, by coating the surface of the transparent base material 11 with the colored hot melt adhesive layer 12, lowering the temp. to put this layer into a solidified or semisoldified state and dispersing and arranging the spheruler transparent beads 13 thereon. The spherular transparent beads 13 are pressed and embedded by the prescribed depth under a prescribed pressure while the colored hot melt layer 12 is melted or softened by using a press device having a hot pressurizing plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmissive screen of a rear projection display device, a viewing angle widening plate for a liquid crystal display device, a plasma display device, an electroluminescence display device, a liquid crystal backlight, and various illumination light sources. The present invention relates to a planar lens used for a light diffusion plate or the like that diffuses light such as.

[0002]

2. Description of the Related Art In recent years, a projection type display device has been developed which uses a light valve such as a liquid crystal panel for emitting a light beam having a polarization characteristic. In a projection display device using this liquid crystal, image light spatially modulated by a liquid crystal panel is enlarged and projected on a screen by a projection lens. This projection type display device includes a front projection type and a rear projection type.

FIG. 15 is a schematic diagram showing the configuration of a rear projection type display device for observing an image projected from the rear side of the screen from the front side of the screen. As shown in FIG. 15, this rear projection display device includes a projection optical system 1 for emitting light, a transmissive screen 2, and a projection optical system 1.
And a mirror 3 that reflects the light L emitted from the and guides the transmissive screen 2. This transmissive screen 2 is
Usually, as shown in the schematic sectional view of the main part of FIG. 16, it is composed of a Fresnel lens 4 and a lenticular lens 5.

In the rear projection type display device having the above-mentioned structure, the light L projected from the projection optical system 1 becomes almost parallel light by the Fresnel lens 4 and is further diffused right and left by the lenticular lens 5. in this way,
In this conventional normal rear projection display device, the projection optical system 1
The image light emitted from the projector is enlarged and projected on the transmissive screen 2. That is, the observer observes the projected image as the transmitted light of the transmissive screen 2 from the opposite side of the projection optical system 1.

Generally, a rear projection type display device is
It is often used in a bright room, in which case ambient light such as indoor lighting is reflected by the surface of the lenticular lens 5, and this is emitted along with image light from a transmissive screen to lower the image contrast. It was
Conventionally, as a countermeasure, a separate smoke plate (not shown) is provided on the front surface of the lenticular lens 5 to absorb a part of disturbance light, thereby adopting a method of suppressing a decrease in contrast. I have.

[0006]

By the way, when the smoke plate is provided as described above, when the smoke plate is passed through, a part of the image light is also absorbed and the brightness of the image is lowered. There is a problem that sufficient brightness cannot be obtained unless a light source with high power is used. Also,
When the power consumption is increased in this way, a stricter measure against heat is required, which causes a new problem of increasing cost.

Further, since the lenticular lens diffuses the image light mainly in the left-right (horizontal) direction as described above, the image can be observed even when viewed obliquely. Since there is almost no diffusion in the) direction, there is a drawback that the range in which a clear image can be observed is extremely narrow when the viewpoint is moved up and down.

Further, in the lenticular lens, since linear lenses extend in the vertical direction and are regularly arranged, there is a problem that moire interference fringes are generated in an image and the image quality is remarkably deteriorated.

Further, the lenticular lens is formed with a precise lens shape over the entire surface, and even if a slight defect occurs in a part, the whole becomes unusable. You need to be very careful. Furthermore, with the recent increase in the projected area of images, the handling of the screen becomes more problematic, and the cost is inevitable.

In the present invention, it is possible to solve the above-mentioned problems, improve the generation of moire interference fringes, and perform diffusion in both horizontal and vertical directions favorably to expand both horizontal and vertical viewing angles. A flat lens having high contrast and high image quality, and a method for manufacturing the same are provided.

[0011]

A flat lens according to the present invention comprises a transparent base material, a colored hot melt adhesive layer formed on the light-incident side of the transparent base material, and the colored hot melt adhesive. It is composed of a large number of microspherical transparent beads consisting of one layer fixed to a layer.

The transparent base material may be composed of a substrate which itself has rigidity, but the transparent base material is a film-like base material, and a transparent adhesive is applied to the surface on the light emitting side of the transparent base material. A rigid transparent substrate can be bonded via the.

In this specification, the term "transparent" means that the desired light, that is, the light that should be transmitted through the lens, can be transmitted therethrough, including so-called semi-transparency. Is.

The colored hot melt adhesive layer may be composed of a colored layer as a whole, or may be composed of a transparent layer and a colored layer formed on the light incident side thereof.

The microsphere-shaped transparent beads have a diameter of 30
% Or more of the colored hot melt adhesive layer is exposed to the light incident side. This is because if the degree of exposure is in this range, the exposed area of the beads will increase,
This is because the brightness of the image light increases as the amount of incident light increases. Therefore, transparent beads have a diameter of 40
It is more preferable to expose at least 50%, and even 50%
It is more preferable to expose the above.

The colored hot-melt adhesive layer, or the colored layer constituting the colored hot-melt adhesive layer,
It is preferably colored with a black or gray pigment or dye. However, red, green, blue, or a mixed color thereof may be used.

Furthermore, the microsphere-shaped transparent beads can be constituted by, for example, glass beads, plastic beads, or the like. The transparent beads preferably have a refractive index of 1.4 or more and a diameter of 100 μm or less. The refractive index is preferably 1.4 or more. When the refractive index is in this range, the incident light is sufficiently condensed and is hardly absorbed by the colored adhesive layer, and the brightness of the image light can be further increased. This is because. Furthermore, the refractive index of the transparent beads is 1.55
It is more preferably 1.95, and 1.60 to 1.90.
More preferably,

The diameter of the transparent microsphere beads is 10
It is preferable that the thickness be 0 μm or less. This is because when the microsphere-shaped transparent beads are densely arranged on the transparent substrate,
This is because the space area between the transparent beads is reduced, the light utilization efficiency is improved, and the resolution is increased. Further, the diameter of the transparent beads is more preferably 90 μm or less, and further preferably 70 μm or less. The lower limit of the diameter of the transparent beads is regulated by the thickness of the hot-melt adhesive layer used for fixing the transparent beads and the transparent substrate, and further, the diameter of the transparent beads is the wavelength range of light. As the scattering factor of the transmitted image light flux becomes large as the distance approaches, the front luminance tends to be lowered, and therefore, it is naturally regulated.

Furthermore, it is preferable that an antireflection layer or an antiglare layer for suppressing or controlling light reflection is formed on the surface of the transparent substrate on the light emission side.

Further, in the method for producing a flat lens according to the present invention, a step of forming a colored hot melt adhesive layer on a transparent substrate, and microsphere-shaped transparent beads on the colored hot melt adhesive layer. The step of dispersing and arranging, the dispersion layer of the microsphere-shaped transparent beads is pressed toward the substrate to soften the colored hot-melt adhesive layer by heating, and the microsphere-shaped transparent beads are dispersed in the colored hot-melt adhesive layer. To
Through the step of embedding each part and the step of solidifying the colored hot melt adhesive layer by lowering the temperature of the colored hot melt adhesive layer and fixing the microsphere-shaped transparent beads, the desired planar lens is obtained. Create.

According to the above-mentioned flat lens having the structure of the present invention, it is possible to form a flat lens having a high contrast. That is, in this configuration, a large number of microspherical transparent beads are fixed to the colored hot-melt adhesive layer, and these microspherical transparent beads are colored hot on the light incident side. Since it is configured to be exposed from the melt adhesive layer, the incident light is efficiently incident on a large number of arranged microsphere transparent beads, that is, the luminous flux incident on the microsphere transparent beads is The microsphere-like transparent beads are once converged and diffused by the lens action.

On the other hand, of the light incident on the plane type lens, the light not incident on the microspherical transparent beads,
That is, the light that is not subjected to the lens action by these transparent beads is almost absorbed by the colored hot melt adhesive layer and is prevented from being transmitted to the front of the flat lens.

Further, most of the external light incident from the front side of the flat lens according to the present invention, that is, the original light emitting side is absorbed by the colored hot-melt adhesive layer, so that it becomes stray light and is observed from the front side. What is done is effectively avoided.

Therefore, according to the planar lens of the present invention, the desired light can be effectively derived,
The contrast can be improved.

Further, according to the above-mentioned production method of the present invention, the microsphere-shaped transparent beads are fixed by dispersing the microsphere-shaped transparent beads in which the microsphere-shaped transparent beads are dispersed and arranged on the colored hot-melt adhesive layer. A layer is formed, and then a dispersion layer of the microsphere-shaped transparent beads is formed by heating and softening the colored hot-melt adhesive layer to embed a part of the microspherical transparent beads in the colored hot-melt adhesive layer. Since the method of solidifying and fixing the colored hot melt adhesive layer is used,
Since the microsphere-shaped transparent beads can be embedded in a predetermined depth while being surely dispersed in a predetermined density, it is possible to fabricate a flat lens that is optically uniform and mass-produced. it can.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are
1 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

First, in the flat lens 10 shown in FIG. 1, a transparent base material 11, a colored hot melt adhesive layer 12 formed on the light incident side surface of the transparent base material 11, and this colored hot melt adhesive. It is constituted by a large number of microsphere-shaped transparent beads 13 which are fixed to the agent layer 12.

The manufacturing method for obtaining the planar lens 10 is as follows.
The colored hot-melt adhesive layer 12 is formed or coated on the transparent substrate 11, and is once cooled by natural cooling or forced cooling to be solidified or semi-solidified, and the microspherical transparent beads 13 are formed on the transparent hot-melt adhesive layer 12. 1
Layers, i.e. single particle layer arrangements are distributed. This is placed on one of the heating / pressurizing plates 22 using a pressing device having a pair of heating / pressurizing plates 21 and 22 whose schematic sectional view is shown in FIG. The microsphere-shaped transparent beads 13 are pressed toward the colored hot-melt adhesive layer 12 with a predetermined pressure while melting or softening the colored hot-melt adhesive layer 12 to form the microsphere-shaped transparent beads 13 in a part of the diameter thereof. That is, the colored hot melt adhesive layer 12 is colored to a predetermined depth.
Embedded inside. Then, heating and pressurization by the heating and pressing plates 21 and 22 are eliminated, and the colored hot melt adhesive layer 1
2 is naturally cooled or forcedly cooled to room temperature to solidify the colored hot melt adhesive layer 12.

According to this method, the colored hot melt adhesive layer 1 which is coated on the base material 11 and is in a solidified state.
Since the microsphere-shaped transparent beads 13 are arranged on the surface 2, the arrangement can be easily arranged densely, that is, with a maximum packing density in a single layer. In this state, the colored hot-melt adhesive layer is again colored. 12 is softened, and transparent beads 13 are added in the colored hot melt adhesive layer 12.
By embedding by pressure, the transparent beads can be embedded with a uniform arrangement density and a portion corresponding to a uniform depth, that is, a constant diameter.

Another embodiment of the planar lens is shown in FIG.
Shown in This structure is similar to the structure shown in FIG.
The colored hot melt adhesive layer 12 is composed of a transparent layer 14 formed on the light incident side surface of the transparent substrate 11 and a colored layer 15 formed on the transparent layer 14.

Further, as another embodiment, there is a flat lens shown in FIG. This structure is the same as the structure shown in FIG. 1 or FIG. 2, but the antireflection film 16 is formed on the exposed surface of the microspherical transparent beads 13 exposed from the colored hot melt adhesive layer 12. . This antireflection film 16 is formed by vacuum vapor deposition, for example, SiO ₂ , TiO ₂ .
A thin film of ₂ , MgF ₂ or the like is formed in a single layer or a multi-layer. The antireflection film 16 is formed by a known technique such as coating other than vacuum deposition. With the configuration of the antireflection film 16, reflection of incident light from the transparent beads 13 is suppressed, and the transmittance is improved.

Further, as another embodiment, there is a flat lens shown in FIG. This structure is similar to the structure shown in FIG. 1 or 2, but is characterized in that the surface of the transparent substrate 11 on the light emitting side is an antireflection surface or an antiglare surface 17. This anti-reflection or anti-glare surface 1
By forming 7, the regular reflection on the surface of the transparent base material 11 of the disturbance light incident from the outside on the surface on the light emission side of the transparent base material 11 can be suppressed, and as a result, the deterioration of the image contrast can be avoided.

Further, as another embodiment, there is a flat lens shown in FIG. This structure is similar to the structure shown in FIG. 1 or 2, but a polarizing member, that is, a polarizing layer 18 is formed on the surface of the transparent substrate 11 on the light emitting side.
By forming the polarizing layer 18, the amount of ambient light 20 transmitted through the planar lens can be reduced to about 1/2, and as a result, the contrast of the image can be increased.

2 to 5, parts corresponding to those in FIG. 1 are designated by the same reference numerals and duplicate description will be omitted.

Further, as another embodiment, FIGS.
There is a planar lens shown in FIG. 6 to 10
1 to 5, the transparent lens 11 is formed of a film-shaped substrate, and a transparent adhesive layer is formed on the light-exiting surface of the film-shaped transparent substrate 11. A rigid transparent substrate 41 is joined via 42.

6 to 10, parts corresponding to those in FIGS. 1 to 5 are designated by the same reference numerals, and duplicate description will be omitted.

In each of the above-mentioned structures, the microsphere-shaped transparent beads 13 have a refractive index of 1.4 or more and a diameter of 100 μm or less, and 30% of the diameter of the transparent beads 13 is contained in the colored hot melt adhesive layer 12. The above is exposed and buried.

The transparent substrates 11 and 41 applied in each of the embodiments are transparent resins such as acrylic resin, polycarbonate resin, vinyl chloride resin, polyolefin resin, polyester resin, polystyrene resin and the like. Is used.

Further, the antireflection surface or the antiglare surface provided on the light emitting surface of the transparent substrate 11 is not particularly limited. There is a method of forming a known antireflection film 16 of silica, alumina or the like on the top by coating or vacuum deposition to a predetermined thickness. Further, on the anti-glare surface, there are a method of coating silica by mixing silica, plastic beads and the like with a resin, and a method of forming irregularities by a sand blast treatment or an embossing treatment.

Further, the colored hot melt adhesive layer 12 or the colored layer 15 thereof applied to each embodiment has sufficient adhesive force to the transparent beads 13 and the transparent substrate 11. Its material is hot resin made of acrylic resin, polycarbonate resin, polyolefin resin, polystyrene resin, polyester resin, polyurethane resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride / vinyl acetate copolymer, polyamide resin, etc. A melt adhesive is used. The colored hot-melt adhesive layer 12 or its colored layer 15 is formed by using these adhesives as a base resin and dispersing a pigment therein or dyeing with a dye.

The coating of the colored hot melt adhesive layer 12 can be performed, for example, by a knife coater whose schematic structure is shown in FIG. This knife coater is comprised of an applicator roll 33 which is housed in a bath 31 and is rotated by being immersed in a colored hot melt adhesive 32 in a heated and melted state, a backup roll 34 which sandwiches the transparent base material 11 and rolls, and an application roll. A squeegee 3 that regulates the amount of the adhesive 32 attached to the troll 33
5 and a doctor roll 36 for smoothing the colored hot melt adhesive layer applied on the substrate 11 by the applicator roll 33.

The colored hot-melt adhesive layer 12 may be coated by, for example, roll coating, gravure coating, kiss coating, spray coating, in addition to the above-mentioned knife coating.
Blade coating, rod coating, etc. can be used.
Also, the colored hot melt adhesive is dissolved in the solvent,
It is also possible to form the colored hot melt adhesive layer 12 by using a diluted solution, coating this, and then drying.

Then, the colored hot melt adhesive layer 12
However, in the case of the two-layer structure of the transparent layer 14 and the colored layer 15, the transparent hot melt adhesive is applied by each coating method described above, and subsequently, the colored hot melt adhesive is coated by the same method.

Further, as a polarizing member for forming the polarizing layer 18 on the transparent substrate 11, for example, a polarized film obtained by adsorbing iodine or a photodichroic dye on a film of uniaxially stretched polyvinyl alcohol, polyethylene terephthalate or the like. Those obtained by adhering the child to a transparent base material, or those obtained by adhering the polarizer with the transparent base material sandwiched therebetween are preferably used. As the transparent substrate used here,
For example, one kind or two kinds are selectively used in combination from acrylic resin, polycarbonate resin, vinyl chloride resin, polyolefin resin, polyester resin, cellulose resin and the like.

Further, the transparent substrate 11 shown in FIGS.
When a configuration is adopted in which the light emitting surface side of the transparent adhesive layer 42 is bonded to the rigid substrate 41 by the transparent adhesive layer 42, the transparent adhesive layer 42 is a solution type, an emulsion type, a hot melt type, It can be made of a transparent adhesive such as a pressure-sensitive (adhesive) type adhesive, and includes, for example, acrylic resin, polycarbonate resin, polyolefin resin,
Adhesives such as polystyrene resins, polyester resins, polyurethane resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate copolymers and polyamide resins can be used.

Next, the optical function of the flat lens according to the present invention will be described with reference to FIGS. FIG.
In FIG. 14 and FIG. 14, the Fresnel lens 7 for making the image light 6 incident on the plane type lens 10 as substantially parallel light is arranged opposite to the light incidence side of the plane type lens 10 according to the present invention shown in FIGS. 2 and 7, respectively. It has been configured. 13 and 14, parts corresponding to those in FIGS. 2 and 7 are designated by the same reference numerals, and redundant description will be omitted.
According to the flat-type lens 10 of the present invention, the microsphere-shaped transparent beads 13 are densely arranged in one layer, that is, a single particle layer arrangement on the light incident surface side, and a part thereof is colored with the hot melt adhesive layer 12. Since it is fixed by the colored hot melt adhesive layer 12 while being exposed to the light incident side, most of the incident light projected on the transparent beads 13 is
After refraction based on the refractive index of the transparent beads 13, the transparent base material 11 on which the colored hot melt adhesive layer 12 is formed, or the transparent base material 11 and the substrate 41 is transmitted so that almost all luminous flux is isotropic. Light is diffused and emitted. On the other hand, the light 8 that has not entered the transparent beads 13 is absorbed by the colored hot melt adhesive layer 12.

When an antireflection film is formed on the exposed surface of the transparent beads 11 exposed from the colored hot melt adhesive layer 12 on the light incident side, reflection of incident light can be suppressed. Further, the transmittance can be increased.

The ambient light 9 incident from the transparent base material 11 or the substrate 14 is colored hot-melt adhesive layer 12.
However, since most of the light is absorbed here, it is less likely that the light is transmitted through the transparent beads 13 to the inside of, for example, the projection type display device to become stray light, and the contrast of the image can be enhanced.

When the colored hot melt adhesive layer 12 is colored with a black or gray pigment or dye, an image with higher contrast can be obtained.

From the above, the viewer can see a bright and high-contrast image from any angle.

EXAMPLES The present invention will be described in more detail with reference to examples. (Example 1) In Example 1, the planar lens 10 of FIG. 1 was produced as follows. First, on one surface of a flat transparent substrate 11 (thickness: 0.25 mm) made of polyethylene terephthalate resin, a polyester hot melt adhesive (manufactured by Toyobo Co., Ltd., trade name Byron 3) is used.
00) The colored hot-melt adhesive layer 12 containing 3 parts by weight of black carbon was mixed with 100 parts by weight,
It was applied and formed by the knife coater explained in FIG. 12 so as to have a thickness of m. Next, on the colored hot melt adhesive layer 12, fine spherical transparent beads 13 (using glass beads) having a refractive index of 1.80 and an average diameter of 55 μm are densely arranged, and the press explained in FIG. The beads were embedded by holding them at a temperature of 130 ° C. and a pressure of 4 kg / cm ² for 10 minutes by hot pressing with an apparatus and then cooling to room temperature. The thickness of the colored hot melt adhesive layer 12 after the transparent beads 13 were embedded was 20 μm. Also, 64% of the diameter of the transparent beads 13 was exposed in the embedding depth direction.

A projection image is obtained by mounting the flat lens 10 according to the first embodiment in place of the lenticular lens 5 shown in FIG. 16 which constitutes the transmissive screen 2 used in the rear projection display device shown in FIG. Was observed, and a viewing angle of 1.5 times in the horizontal direction and 10 times in the vertical direction was obtained as compared with the screen using the conventional lenticular lens 5. In addition, a high-quality image with high contrast and good resolution was observed.

Example 2 In this Example 2, the planar lens 10 shown in FIG. 2 was manufactured as follows.
First, a transparent layer 14 made of a polyester hot melt adhesive (manufactured by Toyobo Co., Ltd., trade name Byron 560) is formed on one surface of a flat transparent substrate 11 (thickness: 0.25 mm) made of polyethylene terephthalate resin. Then, it was applied by the knife coater explained in FIG. 12 so as to have a thickness of 14 μm after drying, and further a polyester hot melt adhesive (manufactured by Toyobo Co., Ltd., trade name Byron 300) 1
To 100 parts by weight, the coloring layer 15 containing 3 parts by weight of black carbon was applied by a similar knife coater so that the thickness after drying was 10 μm.
A colored hot melt adhesive layer 12 of No. 5 was formed. Next, on the colored hot melt adhesive layer 12,
The fine spherical transparent beads 13 (using glass beads) having a refractive index of 1.80 and an average diameter of 55 μm are densely arranged, and
Temperature of 130 ℃, pressure of 4kg / cm ²
After holding for 10 minutes at room temperature, by cooling to room temperature,
The beads 13 were embedded. The thickness of the colored hot melt adhesive layer 12 after embedding the beads was 20 μm. In addition, 64% of the diameter of the beads 13 was exposed in the embedding depth direction.

The flat screen type lens 10 according to the second embodiment is mounted in place of the lenticular lens 5 shown in FIG. 16 which constitutes the transmissive screen 2 used in the rear projection display apparatus shown in FIG. As a result of observation, a viewing angle of 1.5 times in the horizontal direction and 10 times in the vertical direction was obtained as compared with the screen using the conventional lenticular lens 5.
In addition, a high-quality image with high contrast and good resolution was observed.

Example 3 In this Example 3, the planar lens 10 shown in FIG. 3 was manufactured as follows.
First, the planar lens 10 obtained in the same manner as in Example 2
An antireflection film 16 made of SiO ₂ is formed on the exposed surface of the microspherical transparent beads 13 of 100 nm in thickness by vacuum deposition.
To a thickness of Due to the structure of this antireflection film 16, 64% of the diameter of the beads 13 was exposed in the embedding depth direction.

A projection type image is mounted by replacing the lenticular lens 5 shown in FIG. 16 which constitutes the transmissive screen 2 used in the rear projection display apparatus shown in FIG. 15 with the flat type lens 10 according to the third embodiment. As a result of observation, as in Example 2, a viewing angle of 1.5 times in the horizontal direction and 10 times in the vertical direction was obtained as compared with the screen using the conventional lenticular lens 5. Further, the brightness of the image was improved as compared with Example 2, and an image of high quality with good contrast and resolution was observed.

Example 4 In this Example 4, the planar lens 10 shown in FIG. 4 was manufactured as follows.
First, an antireflection film 17 made of SiO _{2 was formed} to a thickness of 100 nm on the surface of the transparent substrate 11 of the planar lens obtained in the same manner as in Example 2 on the image light emission side by vacuum evaporation. A film was formed. Due to the configuration of the antireflection film 17, 64% of the diameter of the bead was exposed in the embedding depth direction.

A projection image is obtained by mounting the flat lens 10 according to the fourth embodiment instead of the lenticular lens 5 shown in FIG. 16 which constitutes the transmissive screen 2 used in the rear projection display device shown in FIG. As a result of observation, as in Example 2, a viewing angle of 1.5 times in the horizontal direction and 10 times in the vertical direction was obtained as compared with the screen using the conventional lenticular lens 5. Further, the contrast was further improved as compared with Example 2, and there was no adverse effect due to ambient light, and a high-quality image with good resolution could be observed.

Example 5 In this Example 5, the planar lens 10 shown in FIG. 5 was manufactured as follows.
First, a polarizing film (manufactured by Nitto Denko Corporation, trade name NPF-G1225Du) was applied on the surface of the transparent substrate 11 of the flat lens obtained in the same manner as in Example 2 on the image light emission side with an acrylic adhesive. Was used to form a polarizing layer 18.

In place of the lenticular lens 5 shown in FIG. 16 which constitutes the transmissive screen 2 used in the rear projection display device shown in FIG. 15, the flat type lens 10 according to the fifth embodiment is used. When the projected image was observed by mounting the polarizing film and the polarizing film with their transmission axes substantially aligned, and observing the projected image, as in the second embodiment, the conventional lenticular lens 34 is used.
The viewing angle was 1.5 times in the horizontal direction and 10 times in the vertical direction as compared with the screen using. Further, the contrast was further improved as compared with Example 2, and the adverse effect due to ambient light was small, and a high-quality image with good resolution could be observed.

(Example 6) Colored hot melt adhesive layer 1
A planar lens was produced in the same manner as in Example 1 except that the thickness of 2 was 30 μm after drying. The thickness of the colored hot melt adhesive layer 12 after completion was 40 μm. In addition, 27% of the diameter of the microsphere-shaped transparent beads 13 was exposed from the colored adhesive layer 12.

An image is displayed by replacing the lenticular lens 5 shown in FIG. 16 which constitutes the transmissive screen 2 used in the rear projection display device shown in FIG. 15 with the flat lens 10 according to the sixth embodiment. As a result of observation, as compared with the screen using the conventional lenticular lens 5,
A viewing angle of 1.5 times in the horizontal direction and 10 times in the vertical direction was obtained. An image of high quality with good contrast and resolution was observed. The brightness was also higher than that of the screen using the conventional lenticular lens 5 (however, it was slightly lower than that of Example 1).

(Embodiment 7) As the fine spherical transparent beads 13, glass beads were used in place of a refractive index of 1.49 and a diameter of 50.
Except for using μm polymethylmethacrylate beads,
The planar lens 10 was manufactured in the same manner as in Example 1.

The thickness of the colored hot melt adhesive layer 12 after completion was 20 μm. Further, 60% of the diameter of the beads 13 was exposed from the colored hot melt adhesive layer 12.

An image is observed by replacing the lenticular lens 5 shown in FIG. 16 which constitutes the transmissive screen 2 used in the rear projection display device shown in FIG. 15 with the flat lens 10 according to this embodiment. As a result, the viewing angle was 1.2 times in the horizontal direction and 8 times in the vertical direction as compared with the screen using the conventional lenticular lens 5. An image of high quality with good contrast and resolution was observed.

(Embodiment 8) By the same method and structure as in Embodiment 1, a film-shaped transparent substrate 11 in which microsphere-shaped transparent beads 13 are densely arranged and fixed by a colored hot melt adhesive layer 12 is shown in FIG. As shown, a rigid substrate 41 made of an acrylic resin having a thickness of 2 mm and having an acrylic adhesive layer 42 applied to a thickness of 50 μm was bonded on the side opposite to the side having the microspherical transparent beads 13. Thus, a transmissive screen having a practical strength was produced.

The screen thus formed has the same optical characteristics as described in Example 1, that is, horizontal,
And vertical viewing angle and contrast were obtained. (Example 9) By the same method and configuration as in Example 2, a film-shaped transparent substrate in which microsphere-shaped transparent beads 13 are densely arranged and fixed by a colored hot-melt adhesive layer 12 composed of a transparent layer 14 and a colored layer 15. 7, the side opposite to the side having the microsphere-shaped transparent beads 13 on the rigid substrate 41 made of acrylic resin having a thickness of 2 mm coated with the acrylic adhesive layer 42 having a thickness of 50 μm, as shown in FIG. Joined at. Thus, a transmissive screen having a practical strength was produced.

The screen thus formed has the same optical characteristics as described in Example 2, that is, horizontal,
And vertical viewing angle and contrast were obtained. (Example 10) By the same method and configuration as in Example 3, the microsphere-shaped transparent beads 13 were densely arranged and fixed by the colored hot-melt adhesive layer 12 composed of the transparent layer 14 and the colored layer 15 to form the transparent beads 13. , A film-like transparent substrate 11 having an antireflection film 16 formed on the exposed portion on the light incident side
As shown in FIG. 8, on the side opposite to the side having the microsphere-shaped transparent beads 13 on the rigid substrate 41 made of acrylic resin having a thickness of 2 mm coated with the acrylic adhesive layer 42 to a thickness of 50 μm. Joined. Thus, a transmissive screen having a practical strength was produced.

The screen thus formed has the same optical characteristics as described in Example 3, that is, horizontal,
And vertical viewing angle and contrast were obtained.

(Embodiment 11) As shown in FIG. 9, an antireflection film 17 similar to that in Embodiment 4 is formed on one surface, and an acrylic transparent adhesive layer 42 having a thickness of 50 μm is formed on the other surface. A rigid transparent substrate 41 made of a coated acrylic resin having a thickness of 2 mm was prepared. Then, on the side of the transparent substrate 41 having the transparent adhesive layer 42, the colored hot melt adhesive layer 12 composed of the transparent layer 14 and the colored layer 15 is formed into a microspherical transparent material by the same method and configuration as in Example 4. The film-shaped transparent base material 11 on which the beads 13 were densely arranged and fixed was joined on the side opposite to the side having the microsphere-shaped transparent beads 13 to prepare a transmission screen having practical strength.

The screen thus formed has the same optical characteristics as described in Example 4, that is, horizontal,
And vertical viewing angle and contrast were obtained.

Example 12 As shown in FIG. 10, the same polarizing layer 18 as in Example 5 is formed on one surface, and the acrylic transparent adhesive layer 42 is applied to the other surface to a thickness of 50 μm. A rigid transparent substrate 41 made of an acrylic resin having a thickness of 2 mm was prepared. Then, on the side of the transparent substrate 41 having the transparent adhesive layer 42, the colored hot-melt adhesive layer 12 including the transparent layer 14 and the colored layer 15 is formed into a microsphere-shaped transparent material by the same method and configuration as in Example 5. The film-shaped transparent base material 11 on which the beads 13 were densely arranged and fixed was joined on the side opposite to the side having the microsphere-shaped transparent beads 13 to prepare a transmission screen having practical strength.

The screen thus formed has the same optical characteristics as described in Example 5, that is, horizontal,
And vertical viewing angle and contrast were obtained.

As described above, the flat lens according to the present invention can enhance the viewing angle not only in the horizontal direction but also in the vertical direction, and is applied to, for example, a transmissive screen used in a rear projection display device. As a result, a high-quality image with good contrast and resolution can be observed.

Further, in the flat lens according to the present invention, the colored hot melt adhesive layer 12 is used to fix the fine spherical transparent beads 13.
Since it is possible to uniformly disperse the transparent beads 13 and set the embedding amount, it is possible to easily and stably manufacture a planar lens having uniform characteristics.

In the above-mentioned example, the case where the flat lens according to the present invention is applied to the transmissive screen is mainly described. However, a viewing angle widening plate of a liquid crystal display device, a plasma display device, an electroluminescence display device, or a liquid crystal display. It can be used for a back light, a light diffusion plate for diffusing light from various illumination light sources, and the like.

[0076]

As described above, according to the flat lens of the present invention, it is possible to improve the generation of moire interference fringes and to construct a high contrast flat lens. That is, in this configuration, a large number of microspherical transparent beads are fixed to the colored hot-melt adhesive layer, and these microspherical transparent beads are colored hot on the light incident side. Since it is configured to be exposed from the melt adhesive layer, the incident light is efficiently incident on a large number of arranged microsphere transparent beads, that is, the luminous flux incident on the microsphere transparent beads is Since the microsphere-shaped transparent beads are converged by the lens action and diffused in the horizontal and vertical directions, that is, three-dimensionally diffused, the generation of moire interference fringes can be improved, and the viewing angle in both the horizontal and vertical directions can be expanded. it can.

On the other hand, of the light incident on the flat type lens, the light that is not incident on the microspherical transparent beads 13 and is not subjected to the lens action by the transparent beads 13 is
Mostly absorbed by the colored hot melt adhesive layer 12 and prevented from penetrating in front of the planar lens.

Further, most of the outside light incident from the front side of the flat lens 10 according to the present invention, that is, the original light emitting side, is absorbed by the colored hot melt adhesive layer 12, so that it becomes stray light and is forward. What is observed from is effectively avoided.

Therefore, the flat lens according to the present invention has a wide viewing angle when viewed from any direction and can improve the contrast without lowering the brightness of the image.

Further, according to the above-mentioned production method of the present invention, the microsphere-shaped transparent beads 13 are fixed on the colored hot-melt adhesive layer 12 by arranging the microsphere-shaped transparent beads in a dispersed arrangement. The dispersed layer of microsphere-shaped transparent beads is then formed by softening the colored hot-melt adhesive layer by heating and softening to partially embed the microspherical transparent beads in the colored hot-melt adhesive layer. Since the method of solidifying and fixing the colored hot melt adhesive layer is adopted, it is possible to embed the microspherical transparent beads in a state in which they are surely dispersed in a predetermined density and at a predetermined depth. It is possible to fabricate a flat type lens that is optically uniform and mass-produced.

Further, when the antireflection film is formed on the exposed surface of the transparent beads, the reflection of the incident light can be suppressed, so that the transmittance can be further increased.

When the surface of the transparent base material on the light emission side is subjected to antireflection treatment or antiglare treatment, the specular reflection of ambient light is suppressed, and the image incident on the planar lens 10 is It can be observed from the light emitting side without lowering the contrast.

When the polarizing layer 18 is provided on the light emitting side surface of the transparent substrate 11 or the transparent substrate 41 bonded to the light emitting side surface, about 1/2 of the ambient light is absorbed. Therefore, the contrast of the image is not lowered.

Therefore, according to the present invention, a high quality image can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 2 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 3 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 4 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 5 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 6 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 7 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 8 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 9 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 10 is a schematic cross-sectional view showing an embodiment of a flat lens of the present invention.

FIG. 11 is a schematic cross-sectional view of an example of a pressing device used in the method for manufacturing a planar lens according to the present invention.

FIG. 12 is a schematic cross-sectional view of an example of a coating device for a colored hot melt adhesive layer used in the method for manufacturing a flat lens according to the present invention.

FIG. 13 is a schematic cross-sectional view showing an optical action of one embodiment of the flat lens of the present invention.

FIG. 14 is a schematic cross-sectional view showing an optical action of one embodiment of the planar lens of the present invention.

FIG. 15 is a schematic configuration diagram of a general rear projection display device to which a flat lens is applied.

FIG. 16 is a schematic cross-sectional view showing the structure of a conventional flat lens.

[Explanation of symbols]

1 projection optical system, 2 transmissive screen, 3 mirror,
4,7 Fresnel lens, 5 Lenticular lens, 6
Image light, 9 ambient light, 10 planar lens, 11 transparent base material, 12 colored hot melt adhesive layer, 13 microspherical transparent beads, 14 transparent layer, 15 colored layer, 1
6,17 Antireflection film, 18 Polarizing layer, 41 Substrate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location // B29K 67:00 509: 10 (72) Inventor Ken Matsui 6-7 Kita-Shinagawa, Shinagawa-ku, Tokyo No. 35 Sony Corporation (72) Inventor Koji Suzuki 6-7 Kita-Shinagawa, Shinagawa-ku, Tokyo No. 35 Sony Corporation (72) Inventor Kazunori Kawamura 1-1 1-1 Shimohozumi, Ibaraki-shi, Osaka No. 2 Nitto Denko Co., Ltd. (72) Inventor Toshiaki Iwamoto 1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation (72) Inventor, Reiji Hirata 1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture No. Nitto Denko Corporation

Claims (11)

[Claims] 1. A large number of microspheres each comprising a transparent base material, a colored hot-melt adhesive layer formed on the light-incident side of the transparent base material, and a single layer fixed to the colored hot-melt adhesive layer. A planar lens comprising a transparent transparent bead. 2. The transparent base material is formed of a film-shaped base material, and a rigid transparent substrate is bonded to a surface of the transparent base material on a light emitting side via a transparent adhesive. 1. The flat lens according to item 1. 3. The flat lens according to claim 1, wherein the colored hot-melt adhesive layer comprises a transparent layer and a colored layer formed on the transparent layer on the light incident side. 4. The microsphere-shaped transparent beads are arranged such that 30% or more of the diameter thereof is exposed from the colored hot melt adhesive layer to the light incident side. The flat lens according to claim 1, 2 or 3. 5. The colored hot melt adhesive layer is colored black or gray.
The flat lens according to 2, 3, or 4. 6. The flat type according to claim 1, wherein the microspherical transparent beads have a refractive index of 1.4 or more and a diameter of 100 μm or less. lens. 7. The microsphere-shaped transparent beads are made of glass beads.
5. The flat lens according to 5 or 6. 8. The light emitting surface of the transparent base material or the rigid transparent substrate is an antireflection surface or an antiglare surface.
The planar lens according to 6 or 7. 9. An antireflection film for suppressing reflection of the incident light is formed on the exposed surface of the microsphere-shaped transparent beads exposed from the colored hot melt adhesive layer to the light incident side. Claims 1, 2, 3, 4, 5,
The flat lens according to 6, 7, or 8. 10. A polarizing member is provided on a surface of the transparent base material or the rigid transparent substrate on a light emitting side, and the polarizing member is provided on the surface of the transparent base material or the rigid transparent substrate. The flat lens according to item 8 or 9. 11. A step of forming a colored hot melt adhesive layer on a transparent substrate, a step of dispersing and arranging microspherical transparent beads on the colored hot melt adhesive layer, and the above microspherical transparent beads. A step of pressing the dispersion layer toward the base material to soften the colored hot melt adhesive layer by heating to soften the microsphere-shaped transparent beads into the colored hot melt adhesive layer, and a part thereof. A method of manufacturing a flat lens, comprising a step of solidifying the colored hot melt adhesive layer by lowering the temperature of the colored hot melt adhesive layer and fixing the microspherical transparent beads.