JPS5834469Y2 - display device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a new display device, in particular, which introduces light into the thickness of a transparent light guide plate, and displays characters, symbols, etc. formed on the back surface of the light guide plate by the light. In a display device that illuminates the light guide plate, the purpose is to prevent the phenomenon of double display of the display body at the edge of the light guide plate and to provide an extremely easy-to-read display. It is equipped with a transparent light guide plate on which a display body such as the above is formed, and a light source that supplies light into the light guide plate, and a part of the display body formed near the edge of the light guide plate near the edge of the light guide plate. is a distance away from the edge, and the distance is such that when the thickness of the light guide plate is a and the critical angle of the material of the light guide plate is θ, 1 "" is I. shall be.

The details of the present invention will be explained below with reference to the accompanying drawings.

Reference numeral 1 denotes a case with an open front, and a light guide plate 2 made of a transparent material such as acrylic resin is disposed inside the case 1.

The light guide plate 2 has a notch in its front surface at one end in the longitudinal direction, and a thin wall portion 3 is formed therein, and the outer end surface of the thin wall portion 3 is an inclined surface 4 facing forward. The corresponding back surface is the light-receiving surface 5.

6 is case 1. This is a small light bulb attached to the light receiving surface 5.
is placed so as to face it.

Reference numeral 7 designates characters, symbols, etc., which are also formed on the back surface of the light guide plate 2 by printing, foil printing, or the like.

At the end of the light guide plate 2, the display body 7 has a thickness a of the light guide plate 2, where the critical angle of the material of the light guide plate 2 is θ.
It is formed at a position spaced apart from the edge 8 of the back surface by a distance such that #gs#≧1.

For example, if the material of the light guide plate 2 is acrylic resin,
Since the critical angle θ is 42.5°, t@5uzs'';g-1a de/Ω4, so b must be approximately 1.092 times or more than a.

In such a display device, the light from the light bulb 6 enters the light guide plate 2 from the light receiving surface 5, is reflected by the inclined surface 4, changes direction, and changes the wall thickness of the light guide plate 2 by internal reflection. It's transmitted inside.

When the light collides with the display body 7, it is reflected and emitted forward, and as a result, the display body 7 is illuminated and visually recognized when viewed from the front of the light guide plate 2.

In addition, in the display device of the present invention, since the display body 7 is formed at a location separated by the above-mentioned distance, the light l reflected by the display body 7 and directed toward the end surface 9 is entirely at an angle θ1 that is less than the critical angle θ.
Therefore, the beam exits from the end face 9,
Therefore, there is no inconvenience that the display body 7 near the end is displayed twice, and visibility is extremely good.

That is, the case where the display body formed near the end of the light guide plate is displayed twice is the following case.

FIG. 3 is a diagram for explaining such a case, and shows a portion near the edge of the display body 7' and an edge 8 on the back surface of the light guide plate 2'.
The distance b' from the light guide plate 2' is such that α' t as # (by) where θ is the critical angle of the material of the light guide plate 2' and a' is the thickness of the light guide plate 2'.

When such a relationship exists, all the light l' reflected from the portion of the display body 7' near the edge 8' and directed toward the end surface 9' of the light guide plate enters the end surface 9' at an incident angle θ2 of a critical angle of 8 or more. Therefore, since the light is reflected by this surface 9' and emitted to the front of the light guide plate 2', the display body 7' appears to be doubled.

On the other hand, in the display device of the present invention, since the display body 7 is formed at the position described above, the display body 7' arranged near the edge of the light guide plate 2 may be seen twice. Therefore, extremely good visibility can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of the implementation of the display device of the present invention;
FIG. 2 is an enlarged sectional view of the main part, and FIG. 3 is a longitudinal sectional view of the main part showing a comparative example. Explanation of symbols 1...Light guide plate, 6...Light source, 7...Display body, 8...Edge.

Claims (1)

[Claims for Utility Model Registration] A transparent light guide plate on which display elements such as characters and symbols are formed on the back side and a light source that supplies light into the light guide plate, The part of the formed display near the edge of the light guide plate is a distance away from the edge, and when the thickness of the light guide plate is a and the critical angle of the material of the light guide plate is θ, the number tgs From a. A display device characterized in that the distance is such that .