JPH1020798A - Light control film with electromagnetic wave shield - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of a display device and improve light transmissibility by providing a light control film(LCF) having electromagnetic wave shielding function. SOLUTION: In an LCF 1 formed of a film base body 2 and a saw tooth shape part 3 formed at the film base body 2, a louver part 4 with electromagnetic wave shielding function is formed at the saw tooth shape part 3. Since the louver part 4 has electromagnetic wave shielding function, the electromagnetic wave shielding function is not impaired so as to hardly influence the transmissibility of light transmitted through the LCF 1, thereby improving transmissibility.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light control film (hereinafter, referred to as LCF) mounted on the surface of various display devices for adjusting light from the display device, and more particularly to an LCF having an electromagnetic wave shielding function. .

[0002]

2. Description of the Related Art Recent automobiles are equipped with various display devices such as a display panel for displaying a vehicle speed and the status of various devices, and a navigation panel for detecting a current position and displaying the current position along with a map. In such an in-vehicle display device, various filters are used in view of being used under special conditions such as in an automobile running outdoors.

For example, a filter having an anti-reflection film is used because visibility is reduced when external light is reflected. Also, a filter having an electromagnetic wave shielding film such as ITO (indium-tin oxide) has been used in order to block electromagnetic waves from the display device or to prevent electromagnetic waves from entering from outside. Further, in order to prevent light from the display device from being projected onto a vehicle window at night or the like, an LCF that regulates light from the display device in a certain direction is used.

[0004] As this LCF, for example,
As disclosed in Japanese Patent Application Laid-Open No. 2004-2004, there is known one having louvers arranged at predetermined intervals inside. As the structure, as shown in FIG. 8, louvers are formed by arranging minute projections 102 having a rectangular cross section at predetermined intervals on a base film 101 such as a polyester film. Is provided. Base film 10
1 and the protrusion 102, and between the protrusion 102 and the covering film 103, a fixing layer 104 is provided, respectively.
Each member is mutually integrated. As an example of the thickness of each member, the base film 101 is 0.18 mm, the height of the protrusion 102 is 0.15 mm,
Is about 0.3 mm, and the fixing layer 104 is made of an adhesive or a pressure-sensitive adhesive and has a thickness of about 0.1 mm.

In order to use the LCF 100 for a display of an automobile, for example, the upper side of FIG. 8 becomes a table, and the display contents drawn on the cover film 103 or the display plate (not shown) superimposed on the cover film 103 are drawn. The displayed content is illuminated by a light source 105 provided on the back side. The light emitted from the light source 105 is
The direction of transmission is regulated by the louver portion composed of the protrusion 102, and only light rays within the visible angle θ determined by the height and the interval of the protrusion 102 are transmitted, and scattering to the surroundings is prevented.

FIG. 9 shows an example in which such an LCF 100 is used for a navigation panel. The navigation panel in this example includes a liquid crystal display 200 and a backlight 201 arranged on the back side of the liquid crystal display 200.
And an ITO formed on the front surface of the liquid crystal display 200
A film 202 and an LCF disposed in front of the ITO film 202
100.

According to this navigation panel, light from the backlight 201 transmitted through the liquid crystal display 200 transmits through the ITO film 202 and then passes through the LCF 100.
The light is transmitted through the light source, and is prevented from being projected onto the vehicle window. The presence of the ITO film 202 prevents electromagnetic waves from entering the liquid crystal display 200 from the outside.

As the louvers, those which are parallel to the display surface of the LCF or those which are inclined at a predetermined angle are known.

[0009]

However, in the above-described conventional display device, a glass substrate for forming the ITO film 202 is required, and light from the backlight 201 is supplied to the liquid crystal display 200, a glass substrate (not shown), the ITO film, and the like. The image is displayed after transmitting through the 202 and the LCF 100 in order. Therefore, light is absorbed or scattered in the optical path, and there is a problem that the light transmittance is reduced as a whole, and improvement of the light transmittance is desired.

Further, since the ITO film 202 and the LCF 100 are formed, there is a problem that the structure is complicated and the number of manufacturing steps is increased. The present invention has been made in view of such circumstances, and has an LC having an electromagnetic wave shielding function.
The purpose of F is to simplify the structure of the display device and improve the light transmittance.

[0011]

Means for Solving the Problems The feature of the LCF with an electromagnetic wave shield according to the present invention that solves the above-mentioned problems is that an LCF having a film base and a louver portion formed on the film base is provided.
In CF, the louver portion has an electromagnetic wave shielding function.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION LC with electromagnetic wave shield of the present invention
In F, the louver portion has an electromagnetic wave shielding function. Therefore, the electromagnetic waves can be shielded by the louver portion. On the other hand, the louver portion regulates the direction of light, and does not need to actively transmit light. That is, even if the light transmittance of the louver portion is low, if it is only the louver portion, the transmittance of light transmitted through the LCF is hardly affected. Therefore, the light transmittance as a whole is improved as compared with a case where an ITO film is separately provided as an electromagnetic wave shielding layer as in the related art.

As the film substrate, the same materials as those of the prior art, such as transparent resins such as polyester, acrylic resin, polycarbonate and cellulose, and glass can be used. In order to provide the louver portion with an electromagnetic wave shielding function, a method of forming the louver portion from a conductive material or a method of forming a conductive electromagnetic wave shielding layer on at least the surface of the louver portion can be adopted. Examples of the material having the electromagnetic wave shielding function include a conductive metal, carbon black, and ITO. For example, in order to form the electromagnetic wave shielding layer, PVD such as evaporation and sputtering is used.
It can be formed by a method such as a method, a CVD method, or a coating method. There is no particular limitation on the thickness of the formed electromagnetic wave shielding layer, but it is desirable to make it as thin as possible in order to maintain a higher light transmittance.

If this electromagnetic wave shielding layer is provided on at least a part of the louver portion, a certain electromagnetic wave shielding effect is exhibited, but it is desirable that the electromagnetic wave shielding layer is formed uniformly over the entire louver portion. Further, as described above, the louver portion itself can be formed from a conductive material, and the entire louver portion can have an electromagnetic wave shielding function. Note that the louver portion having the electromagnetic wave shielding function can be used even when a voltage is applied.However, when it is used for a display for an automobile, it is most likely that the power supply voltage displacement is large, and extraneous or self-generated noise is large. It is preferably used as a stable ground potential.

The LCF of the present invention can be provided not only in various display devices such as a CRT, liquid crystal, plasma, LED, and EL, but also in sunglasses, sun visors, and the like.

[0016]

The present invention will be described below in detail with reference to examples. (Embodiment 1) FIGS. 1 and 2 show an LCF according to an embodiment of the present invention.
Is shown. The LCF 1 includes a film base 2 made of an acrylic resin and a saw-toothed portion 3.

The film substrate 2 is in the form of a flat plate having a thickness of about 0.5 mm, and has a horizontal surface 30 and an inclined surface 31 on one surface.
Are formed alternately and continuously in a saw-tooth shape. The sawtooth-shaped portion 3 also functions as an anti-reflection layer because its cross section has a sawtooth shape. On the horizontal surface 30 of the sawtooth-shaped portion 3 parallel to the thickness direction of the film substrate 2, a louver portion 4 having a thickness of 10 μm and made of a metal such as copper or silver and having an electromagnetic wave shielding function is formed.

The inclined surface 3 at one end of the sawtooth-shaped portion 3
1, a conductive layer 40 for conducting all the louver portions 4 is formed, and the conductive layer 40 is used by being grounded. This LC
F1 first forms a film substrate 2 having a sawtooth-shaped portion 3 from an acrylic resin by injection molding. Next, the film substrate 2 is masked, and the louver portions 4 are formed on all the horizontal surfaces 30 of the sawtooth-shaped portion 3 by sputtering using a conductive metal such as copper or silver as a target. Next, a conductive paste mainly containing a conductive metal powder such as copper or silver was applied and dried to form a conductive layer 40.

As shown in FIG. 3, the LCF 1 is disposed on the front surface of the liquid crystal display 200 such that the surface opposite to the surface having the sawtooth-shaped portion 3 faces the liquid crystal display 200, and the conductive layer 40 is grounded. It is used as a potential. A backlight 201 is provided behind the liquid crystal display 200, and light from the backlight 201 passes through the liquid crystal display 200 and the LCF1, and
Display can be performed on the surface of F1.

Further, the presence of the louver portion 4 which is at the ground potential and has an electromagnetic wave shielding function,
Through the liquid crystal display 200 is prevented. Further, since the saw-tooth-shaped portion 3 is located on the outermost surface, external light is irregularly reflected and has an anti-reflection function.

The light radiated from the liquid crystal display 200 passes through the inclined surface 31 of the sawtooth-shaped portion 3 and is radiated.
Radiated from one surface. Since the louver portion 4 is at the set potential and has an electromagnetic wave shielding function, there is no glass substrate or ITO film as in the prior art, and light is directly
Since the radiation is transmitted through F1, a high transmittance is obtained.

In the above embodiment, the louver portion 4 is formed on the horizontal surface 30 parallel to the light transmission direction. However, as shown in FIG. The configuration in which the portion 4 is formed may be adopted. Embodiment 2 FIG. 5 shows an LCF of this embodiment. This LC
F is CAB (cellulose acetate butyrate)
And a louver portion 5 made of conductive carbon black and having an electromagnetic wave shielding function are alternately laminated in a plate-like shape to form a sandwich structure sandwiched between two polycarbonate films 20. The thickness is 3.0 mm. A coating layer 6 made of conductive carbon black is formed on one side surface of the film substrate 2, and the coating layer 6 is electrically connected to each louver portion 5.

This LCF1 was manufactured as follows. As shown in FIG.
A μm transparent CAB film 11 is prepared, and carbon black is applied to one surface thereof to a thickness of 10 μm to form a carbon layer 12. A predetermined number of CAB films 11 each having the carbon layer 12 thus formed are laminated,
It is cut in the stacking direction as shown by the dashed line. Thereafter, a coating liquid containing conductive carbon black was applied to one side surface of the cut body and dried to form a conductive layer 6. Thereafter, two polycarbonate films 20 were bonded to both front and back surfaces by using an adhesive, thereby producing LCF1 of this example.

The LCF 1 is used in the same manner as in the first embodiment, except that the conductive layer 6 is grounded and the louver portions 5 are set to the ground potential. Then, as shown in FIG. 7, the light emitted from the liquid crystal display 200 transmits through the transparent film substrate 2 of the LCF 1 and is hardly obstructed by the thin louver portion 5, so that it shows a high transmittance. However, since the louver portion 5 is opaque, it has a louver function,
The light emitted from the liquid crystal display 200 is conditioned by the LC1F.

The louver portion 5 at the ground potential allows
Electromagnetic waves from outside can be reliably shielded.

[0026]

That is, the L with the electromagnetic wave shield of the present invention.
According to the CF, since it has both the light regulating function and the electromagnetic wave shielding function, when it is provided in a display device, an electromagnetic wave shielding film or the like becomes unnecessary, and the light transmittance is improved. Further, when the filter is provided in the display device, the number of filters to be used can be reduced, and the cost can be reduced due to the reduction in the number of steps and the number of components.

[Brief description of the drawings]

FIG. 1 is a perspective view of an LCF according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of an LCF according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a display panel using an LCF according to one embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a configuration of a display panel using an LCF according to another embodiment of the present invention.

FIG. 5 is a perspective view of an LCF according to a second embodiment of the present invention.

FIG. 6 is an explanatory view showing a method for manufacturing an LCF according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a configuration of a display panel using an LCF according to a second embodiment of the present invention.

FIG. 8 is a sectional view of a main part of a conventional LCF.

FIG. 9 is an explanatory diagram showing a configuration of a display panel using a conventional LCF.

[Explanation of symbols]

1: LCF 2: Film substrate
3: Sawtooth shape part 4: Louver part 5: Louver part
6: conductive layer 30: horizontal surface 31: inclined surface
40: conductive layer

Claims (1)

[Claims] 1. A light control film having an electromagnetic wave shield, wherein the light control film comprises a film substrate and a louver portion formed on the film substrate, wherein the louver portion has an electromagnetic wave shielding function.