JPH06342187A - Lens sheet - Google Patents

Abstract

PURPOSE:To obtain an excellent inconspicuous image in a joining part by joining plural lens sheets by mutually adhering without interposing another adhesive layer. CONSTITUTION:Plural lenticular lens sheets 61, 62 are joined by mutually adhering in the scene. The lens sheets 61, 62 to be joined may be a transparent or translucent resin plate and may also contain a light diffusing agent. The lens sheets are joined by cutting the lens sheets so that the pitch at the valley part is the same as that of another lenticular lens and butting the joining surfaces. In the case of executing adhering by dissolving an adhesive with a solvent, the solvent to be used may be one capable of dissolving a base material, for instance, toluene, xylene, ethyl acetate, methylene chloride or the like can be used alone or in combination. The lens sheets may be mutually adhered by hot melting. By executing adhering in this way, the continuity of the lens shape is not impaired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens sheet such as a joined lenticular lens sheet used in a large-sized projection television.

[0002]

2. Description of the Related Art In a transmissive screen used for a projection television, a horizontal diffusion lenticular lens sheet is generally arranged on the exit side. In recent years, projection televisions are becoming larger in size, and a large lenticular lens sheet used for this is one in which a plurality of lenticular lens sheets with a width of about 1 m are joined (FIG. 1).

The reason why the lenticular lens sheet is bonded and used in this manner is that the manufacturing size of the lenticular lens sheet is limited in terms of manufacturing method and manufacturing apparatus. As a joining method, the actual method is Sho 58-144.
No. 340, No. 63-200832, No. 64-64
As described in Japanese Patent No. 23042 and the like, it is general that an adhesive having an optical performance substantially equal to that of the lenticular lens sheet is provided as an adhesive layer for bonding. For example, FIGS. 2 and 3 show a lenticular lens sheet joined by a conventional method, which is joined at an end portion of the lenticular lens via an adhesive layer.

[0004]

However, the conventional lens sheet joined by the above-mentioned method has the following problems.

That is, since the external light absorption layer is missing in the adhesive layer portion, a step of newly providing the external light absorption layer in that portion is necessary. If the external light absorption layer is not provided in that part, the leakage of the projection light will occur, or the discontinuous part will occur in the external light absorption layer, and it will be recognized as a white line due to the external light reflection. . For example, in the lenticular lens sheet as shown in FIG. 2, even if an external light absorbing layer is newly provided, the external light absorbing layer is widened by the width of the adhesive layer and is recognized as a discontinuous portion. Moreover, in the lenticular lens sheet as shown in FIG.
Since the valley of the lenticular lens is missing by the width of the adhesive layer, the projected light is not sufficiently diffused, and when the image is viewed from an angle, it is recognized as a black line on the image surface corresponding to that part. I will end up.

Further, as a manufacturing problem, since the adhesive adheres to the lenticular lens and the surface of the adhesive layer on the entrance / exit side cannot be finished to be a flat surface, the adhesive part adhered to the lenticular lens is In addition, the incident light is reflected and scattered on the incident surface of the adhesive layer and is recognized as a discontinuous portion. That is, an object of the present invention due to the above problems is to make the width of the external light absorption layer equal to the width of other external light absorption layers at the joint portion, and to eliminate the lack of the valley portion of the lenticular lens, Eliminating the step of providing the light absorbing layer, and not attaching an adhesive to the lenticular lens.

[0007]

The present inventors have completed the present invention as a result of intensive studies to solve these problems. That is, the present invention relates to a lens sheet in which a plurality of lens sheets are bonded by mutual adhesion without interposing another adhesive layer.

The present invention will be described in detail below with reference to a lenticular lens sheet.

FIG. 4 is a sectional view of the lens sheet of the present invention. A plurality of lenticular lens sheets are joined together at their end faces by mutual adhesion.

The lens sheet to be joined is transparent or
It may be a translucent resin plate and may contain a light diffusing agent. As its material, for example, polymethylmethacrylate, polycarbonate, polystyrene, a copolymer of styrene and methylmethacrylate, or the like can be used.

As for the method of joining, first, the joining surface of the lens sheet is cut at a predetermined position using a router processing machine or a circular saw. For example, in a lenticular lens sheet, the lenticular lens valleys are cut to have the same pitch as other lenticular lenses. When the cut surface has irregularities, surface finishing may be performed with sandpaper or the like.

Next, the joint surfaces are butt-bonded to each other, but in order to obtain the flatness of the joint, it is preferable to place them on a surface plate having a good plane accuracy and butt them.

When the lens sheets are adhered to each other by dissolution with a solvent, the solvent used may be any solvent capable of dissolving the substrate, for example, toluene, xylene, ethyl acetate, methylene chloride, dichloroethane, tetrahydrofuran, methyl ethyl ketone, etc. Each may be used alone or in a mixture. These solvents are poured into the abutted joints by, for example, a syringe or the like, and melted and adhered. It is also possible to bond the lens sheets to each other by heat melting, in which case the surfaces to be joined are pressed against the hot plates to melt them, and then the hot plates are bonded to each other, and the surfaces to be bonded are butted together. Ultrasonic bonding, which heats and melts and bonds by sonic vibration, and friction bonding, which heats and melts by bonding the joining surfaces by rubbing on a surface plate and bonding, are used.

In the present invention, the width W of the external light absorption layer at the joint is W.
_When the relation between ₁ and the width W of the external light absorption layer other than the joint portion and the relation between the pitch P ₁ of the lenticular lens at the joint portion and the pitch P thereof other than the joint portion are examined, the following matters are found. . That is, in the present invention, the width W ₁ of the external light absorption layer at the junction is relative to the width W of the light absorption layer other than the junction.
Is preferably 0.5W <W ₁ <1.5W.

Below 0.5 W or above 1.5 W,
This is because the joint is clearly recognized. Further, the pitch P _{1 of the} joint portion with respect to the pitch P of the lenticular lens other than the joint portion is 0.85P <P ₁ <1.1
It is preferably 5P. When P ₁ is 0.85 P or less, or 1.15 P or more, the projection light is not diffused to the left and right, so when viewed at an angle of about 45 ° to the screen, the joint May be clearly recognized.

The gap between the lenticular lens sheets formed at the joint is preferably 100 μm or less. If it exceeds 100 μm, leakage of the projected light will occur and the joint will be clearly recognized.

As the type of lens sheet, in addition to the above-mentioned lenticular lens sheet provided with the external light absorbing layer, a lenticular lens sheet having a sectional shape as shown in FIG. 5 and a linear Fresnel having a sectional shape as shown in FIG. A lens sheet or a prism sheet may be used. The joining position is preferably the position shown in the figure from the viewpoint that the optical performance is not impaired and the seam is less noticeable.

[0018]

As described above, the lens sheets of the present invention are joined by mutual adhesion and there is no adhesive resin layer at the joined portion, so that the continuity of the lens shape is not impaired.

Further, since no adhesive resin is used and the adhesive resin does not adhere to the lens surface, reflection of projection light,
No scattering occurs. Further, in the joining of the lenticular lens sheet provided with the external light absorbing layer, the step of newly providing the external light absorbing layer at the joining portion is unnecessary.

[0020]

The present invention will be described in detail below with reference to the drawings and the like.

FIG. 7 is a diagram for explaining the shape of the lenticular lens sheet used in the embodiment of the lens sheet according to the present invention, and FIG. 4 is a diagram for explaining the embodiment of the lens sheet according to the present invention.

The lenticular lens sheets 61 and 62 are extruded sheets of polymethylmethacrylate having a width of 0.9 m and a length of 1.3 m, the surfaces to be joined are router-cut at the valleys of the lenticular lens. The shape of the lenticular lenses of the lenticular lens sheets 61 and 62 is, as shown in FIG. 7, an incident side lenticular lens pitch P = 0.
9 mm external light absorption layer width W = 0.45 mm, sheet thickness t =
It is 1.2 mm. (Example 1) The surfaces of the lenticular lens sheets 61 and 62, which were router-cut at the valleys of the lenticular lenses, were butted on a surface plate which was made by milling a brass plate to form a flat surface, and were mixed with 50 wt% of methylene chloride and 50 wt% of methyl ethyl ketone. The mixed solvent was poured along the joint surface with a syringe. The joint surface is dissolved by the solvent,
The solvent that was adhered and adhered to the lens surface and the surface of the external light absorption layer immediately vaporized.

After the adhesive surface is completely solidified, the width W ₁ of the external light absorbing layer at the joint and the lenticular lens pitch P ₁₁ ,
P ₁₂ was measured with a microscope. W ₁ = 0.4
6 mm, P ₁₁ = 0.87 mm, P ₁₂ = 0.94 mm, and the clearance between the lenticular lens sheets 61 and 62 was 0.01 mm. Next, the joined lenticular lens sheet was combined with a Fresnel lens sheet, set on a projection television, and white light was projected to observe an image. 45 ° to the front and left and right with respect to the screen
Observed at a nearby angle, the joint could not be recognized. Similar observations were made with the projected light extinguished, but no joint was recognized. (Example 2) The joining surfaces of the lenticular lens sheets 61 and 62, which were router-cut at the valley portions of the lenticular lenses, were brought into close contact with a hot plate heated to 180 ° C for about 15 seconds, and immediately thereafter, the joining surfaces were pressed on a surface plate. Pressed and held. After the bonding surface was solidified, the width W ₁ of the external light absorption layer and the lenticular lens pitches P ₁₁ and P ₁₂ at the bonding portion were measured in the same manner as in Example 1. W ₁ = 0.40 mm, P ₁₁ = 0.88 mm,
P ₁₂ = 0.87 mm, lenticular lens sheet 61
The gap between and 62 was 0.01 mm or less. Next, the image was observed in the same manner as in Example 1, but no joint was recognized.

[0024]

The large-sized lens sheet of the present invention, in which a plurality of lens sheets are joined, is made by bonding the lens sheets to each other without interposing an adhesive resin layer. Video can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a joined lens sheet.

FIG. 2 is a view showing a conventional example of a joined lens sheet.

FIG. 3 is a view showing a conventional example of a joined lens sheet.

FIG. 4 is a diagram for explaining an example of a lens sheet according to the present invention.

FIG. 5 is a diagram for explaining an example of a lens sheet according to the present invention.

FIG. 6 is a diagram for explaining an example of a lens sheet according to the present invention.

FIG. 7 is a diagram for explaining the shape of a lenticular lens sheet used in an example of a lens sheet according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Bonded lenticular lens sheet 2 Bonding part 3 Adhesive resin layer 4 External light absorbing layer 5 External light absorbing layer at bonding part 61,62 Lenticular lens sheet 7 Bonding part of lens sheet of the present invention P Lenticular other than bonding part Lens pitch P ₁₁ , P ₁₂ Lenticular lens pitch at the joint W W Width of outside light absorption layer other than the joint W ₁ Width of outside light absorption layer at the joint

Claims (6)

[Claims] 1. A lens sheet, wherein a plurality of lens sheets are bonded by mutual adhesion without interposing another adhesive resin layer. 2. The lens sheet according to claim 1, wherein mutual adhesion is achieved by dissolution with a solvent. 3. The lens sheet according to claim 1, wherein mutual adhesion is achieved by heat fusion. 4. The lens sheet according to claim 1, wherein the lens sheet is a lenticular lens sheet. 5. The lens sheet according to any one of claims 1 to 4, wherein the lens sheets are joined at a valley portion of a lenticular lens. 6. The width W ₁ of the external light absorbing layer at the joint is 0.5 W <W ₁ <1.5 with respect to the width W of the external light absorbing layer other than the joint.
W, and the pitch P ₁ of the lenticular lens at the joint is 0.85P <P ₁ <1.15P with respect to the pitch P of the lenticular lens other than the joint.
The lens sheet described in.