JP3093427B2 - Low reflection sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-reflection sheet which is disposed as a filter on the front of a display such as a CRT or a plasma display panel or a display section such as a meter display device, or is used as a frame. It is intended to make it easier to see through the display of characters, images, and the like arranged at the rear, and to reduce the reflection of the worker himself and its background, thereby improving the visibility of the display.

[0002]

2. Description of the Related Art A conventional low-reflection sheet is formed by forming fine irregularities on the surface of a light-transmitting base sheet to form a mat or mat, thereby scattering reflected light and causing the worker himself or his background to be scattered. Some have blurred images.

Alternatively, a transparent thin film layer made of a compound having a refractive index lower than the refractive index of the light-transmitting substrate sheet is formed on the surface of the light-transmitting substrate sheet, and the reflected light is reduced by utilizing light interference. There is.

[0004]

However, the former light-transmissive base sheet having fine irregularities formed on the surface thereof scatters all the light incident on the surface of the transparent base sheet. The reflected light is greatly reduced, and the reflection of the worker himself and the background can be reduced. However, since the transmitted light from behind the translucent base sheet is also scattered, the display of characters and images arranged behind the sheet becomes dark or blurred, making it difficult to see through.

On the other hand, the latter, in which a transparent thin film layer is formed on the surface of a light-transmitting substrate sheet, allows the characters, images, and the like arranged behind the substrate sheet to be sufficiently seen through, and furthermore, is perpendicular to the transparent substrate sheet surface. It is possible to reduce the reflected light of the incident light so that the worker's own image does not enter the worker's eyes. However, a background image far from the worker enters the eyes of the worker. This is because the effect of reducing the reflected light of the incident light that enters the light-transmitting substrate sheet surface at an angle other than perpendicular is small.

[0006]

According to the present invention, in order to solve the above problems, fine irregularities are formed on at least one surface of a translucent base sheet, and the translucent base sheet is formed on the irregularities. The structure was such that a transparent thin film layer made of a fluorine compound having a refractive index lower than the refractive index and having a thickness in the range of 500 to 5000 ° was formed.

[0007]

[0008]

FIG. 1 is a sectional view showing one embodiment of the low reflection sheet of the present invention. 2 and 3 are sectional views showing another embodiment of the low reflection sheet of the present invention.

The translucent base sheet 1 includes a sheet made of a transparent organic material such as AS resin, acrylic resin, polycarbonate and polyvinyl chloride, and a sheet made of a transparent inorganic material such as glass.

The fine irregularities 2 are formed on at least one surface of the translucent base sheet 1. As a method of forming the fine irregularities 2 on the translucent base sheet 1, there are a stamping method, a casting method, and the like. Alternatively, a method of forming the irregularities 2 directly on the surface of the translucent base sheet 1 by a hairline process, a sandblast process, a press process, or the like may be used. Alternatively, the irregularities 2 may be formed chemically on the surface of the translucent base sheet 1 using an etching agent. Alternatively, an uneven layer 4 having fine unevenness 2 by a printing method or a laminating method.
May be formed on the surface of the smooth translucent base sheet 1 (see FIG. 3).

A transparent thin film layer 3 is formed on a translucent base sheet 1 on which fine irregularities 2 are formed. The transparent thin film layer 3 is formed on the surface of the translucent base sheet 1 and is made of a compound having a refractive index lower than that of the translucent base sheet 1 and having excellent transparency. The transparent thin film layer 3 may be formed on only one surface of the translucent base sheet 1, or may be formed on both surfaces (see FIG. 2). Examples of the forming method include a dipping method, a spin coating method, a transfer method, and a vacuum method.

The transparent thin film layer 3 may be formed on the transparent base sheet 1 so that the surface of the transparent thin film layer 3 becomes uneven along the fine irregularities 2 (see FIG. 1). Alternatively, fine irregularities 2 may be embedded in the translucent base sheet 1 to smooth the surface (see FIG. 2).

The fluorine-based compound having a refractive index lower than that of the translucent base sheet 1 and having excellent transparency is as follows.
There are organic or inorganic fluorine compounds. Examples of the organic fluorinated compound include an amorphous perfluoropolymer. Examples of the inorganic fluorine compound include magnesium fluoride.

The thickness of the transparent thin film layer 3 needs to be changed according to the refractive index of the compound constituting the transparent thin film layer 3, and the thickness may be set according to the following equation. n × d = λ / 4 or n × d = 3λ / 4 (where n is the refractive index of the compound, d is the film thickness of the compound, and λ is the low reflection center wavelength, respectively)

Example 1 A translucent base sheet made of polycarbonate (length 200 ×
One side (width 200 mm × thickness 2 mm) is made uneven by a stamping method, and both sides of this translucent base sheet have a refractive index of 1.
A transparent thin film layer made of 34 fluorine compounds (Cytop manufactured by Asahi Glass Co., Ltd.) is dip-coated so as to have a dry film thickness of 1026 mm. With this low reflection sheet, the worker himself and the image behind it were prevented from directly entering the eyes, and the reflected light was reduced and the amount of transmitted light was increased, so that the characters and images placed behind became bright and easy to see.

Example 2 A translucent base sheet made of methacrylic resin (length 200 ×
Both sides (200 mm wide x 2 mm thick) are made uneven by the casting method.
A transparent thin film layer made of a fluorine compound of 1.31 (TEFLON AF manufactured by DuPont) is dip-coated to a dry film thickness of 1049 mm. This low-reflection sheet has a reflectance of 0.6% for light with a wavelength of 550 nm compared to a sheet without a transparent thin film layer.
Decreased to.

[0017]

The low-reflection sheet of the present invention has a thickness of 500 to 5000 ° made of a fluorine-based compound having a lower refractive index than that of the light-transmitting substrate sheet on the fine irregularities of the light-transmitting substrate sheet.
Since the transparent thin film layer in the range described above is formed, it is possible to reduce reflected light with respect to incident light perpendicular to the surface of the transparent base sheet and incident light incident at an angle other than perpendicular. Therefore, the reflection of the image of the worker himself or the background thereof is reduced, and the visibility of the display is improved.

In addition, a fluorine compound is formed on the unevenness.
Since the transparent thin film layer has a thickness in the range of 500 to 5000 °, scattering of transmitted light from the back of the translucent base sheet is reduced, and the total amount of transmitted light of the translucent base sheet is increased. Therefore, the display of characters, images, and the like arranged behind the seat can be seen brightly.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a low reflection sheet of the present invention.

FIG. 2 is a sectional view showing another embodiment of the low reflection sheet of the present invention.

FIG. 3 is a sectional view showing another embodiment of the low reflection sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent base sheet 2 Irregularity 3 Transparent thin film layer 4 Irregularity layer

Claims (1)

(57) [Claims] 1. A light-transmitting substrate sheet having fine irregularities formed on at least one surface thereof, and a film made of a fluorine-based compound having a refractive index lower than the refractive index of the light-transmitting substrate sheet on the irregularities. A low-reflection sheet comprising a transparent thin film layer having a thickness in the range of 5000 ° .