JP2000039859A - Front light type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front light type display device permitting to recognize an ordinary printed matter as it is even from a position far from the device without making a specially printed display panel for a light transmitting film. SOLUTION: A transparent plate 2 is arranged on a base body 1, and a light source 3 having directivity is parallel to the transparent plate 2 is arranged on a sidewall 1b of the case body 1. The structure is such as an object to be displayed 4 like a poster, etc., can be installed on an internal bottom of this case body 1. In such a manner, it is possible to provide a display device capable of displaying in color as bright as a illumination signboard, a very large type display device used for a conventional illumination signboard, without making a special display panel but by using an object for display printed on a sheet of normal paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front light type display device capable of displaying a poster or the like brightly and clearly by illuminating the front side with a light. More specifically, the present invention relates to a front light type display device that can be used for noticeable objects such as illuminated signboards and advertising towers, and for use in noticeboards that can be clearly recognized even at night.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, for example, an illuminated signboard for an advertisement at a station has a light source such as a fluorescent lamp 21 arranged in a reflection case 22 and via a diffusion plate 23 or directly. By illuminating the display panel or the like, light is emitted from the back side of the display panel, and display is performed by the transmitted light. In such a method of directly irradiating with a fluorescent lamp or the like, if the display panel is too close to a light source such as a fluorescent lamp, the entire surface of the display panel will not have uniform brightness. It is necessary to provide at least 15 cm or more between the lamp and the display panel.

In order to prevent such a depth from increasing, for example, as shown in FIG. 5, light from a linear light source 25 is introduced from a side surface of a light guide plate 24, and light is uniformly emitted from the surface of the light guide plate 24. It is also considered that a display panel is provided on the surface of the light guide plate 24 via the diffusion plate 23 by using a planar light source. 26 indicates a reflection plate. This method is also a method in which light is transmitted from the back side of the display panel and the content displayed on the display panel is recognized by the transmitted light.

On the other hand, as shown in FIG. 6, a fluorescent lamp 28 or the like is provided on an upper part of a bulletin board 27 so as to be able to recognize a display body posted on a normal bulletin board even when it becomes dark at night. There are also notices that can be recognized by the brightness of the reflected light. Reference numeral 29 denotes a reflection cover that covers the light source.

[0005]

In a conventional signboard, a display object to be recognized by transmitted light can be clearly recognized, but the content to be displayed by color printing or the like is printed on a film or the like which transmits light. Thus, a display panel must be formed. This display panel needs to be specially prepared only for the display device, and has a problem that the cost is greatly increased.

[0006] Further, in a conventional bulletin board which is made to be visible at night by arranging a fluorescent lamp or the like on an upper part of the bulletin board, the light from the fluorescent lamp is uniformly irradiated in four directions.
The light is scattered even to the one without the notice. As a result, although the area near the fluorescent light is bright, the lower part of the notice board, which is a little farther away, is darker or darker as a whole, and cannot be recognized unless viewed from a nearby place. There is a problem that it is not suitable for a sign that draws a mark.

The present invention solves such a problem, and makes it possible to recognize a normal printed matter as it is brightly from a distant place without creating a display panel specially printed on a film transmitting light. It is an object of the present invention to provide a front light type display device in which a light source is arranged on a surface side of a display object.

[0008]

According to the present invention, there is provided a front light type display device, comprising: a box having a transparent plate provided on an upper surface thereof;
The light source is provided on at least one side wall of the box, and has a directivity in a direction parallel to the transparent plate, so that a display object can be provided on an inner bottom surface of the box.

As the light source having the directivity, for example, a light source in which a prism sheet is provided on the front surface of a fluorescent tube can be used.

With this configuration, since the light from the light source is radiated in the direction parallel to the transparent plate provided on the front surface side of the box, the light radiated directly to the outside is small, and the light is reflected on the display object. Since the person goes outside, the display object can be clearly recognized by the reflected light. The light directly from the light source toward the transparent plate is also substantially parallel to the transparent plate, that is, toward the transparent plate at a large incident angle, so that the light is totally reflected on the back surface of the transparent plate and directed toward the bottom surface of the box. As a result, it is possible to efficiently irradiate the display object provided on the bottom surface of the box body and display brightly.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a description will be given of a front light type display device for a notice according to the present invention.

FIG. 1 is a cross-sectional view and a plan view of one embodiment of a front light type display device according to the present invention. As shown in FIG. A light source 3 having directivity in a direction parallel to the transparent plate 2 is provided on at least one side wall (two opposing side walls in the example shown in FIG. 1). The box 1 has a structure in which a display 4 such as a poster can be provided on the inner bottom surface.

The box 1 prevents light from leaking to the outside as much as possible, and irradiates the display object 4 provided on the bottom surface with light or reflects internally to reflect the light on the back surface of the transparent plate 2 on the front surface side. Preferably, the inner surface is formed so as to be easily reflected so as to irradiate the display object 4 on the bottom surface. The material may be a metal plate that easily reflects such as aluminum, or a material such as plastic whose inner surface is coated with an easily reflecting paint. In particular, it is preferable to apply a white paint or the like to the inner side surface of the box 1 because the reflection inside the box 1 is further improved and the loss of light is reduced. In the example shown in FIG.
The side wall 1b has an arc shape, but the cross section is triangular,
Other shapes such as a square shape may be used, and the side wall 1b side of the light emitting unit 31 may be covered with an arc-shaped reflector.

As the transparent plate 2, a plate material made of a material that easily transmits light, such as glass, polyester film, and acrylic resin, is used. The light from the light source 3 provided on the side wall is reflected to the bottom side of the box body 1 instead of the purpose of diffusing the light like a diffusion plate, and a smooth planar transparent body is used.

The light source 3 is composed of a light emitting unit 31 such as a fluorescent lamp or a cold cathode tube and a prism sheet 32 provided on the front surface thereof, that is, a prism sheet 32 provided on the side opposite to the side wall 1b of the light emitting unit 31. Has become. The prism sheet 32 has a prism angle θ of, for example, 90 ° and a prism pitch P of, for example, about 50 μm on the surface of a polyester film 32 a having a thickness of, for example, about 127 μm, as shown in FIG. Is formed of an acrylic resin layer 32b having a large number of prism surfaces extending in one direction, and has a total thickness of about 155 μm. By arranging the prism sheet 32 in front of an omnidirectional light emitting portion 32a such as a fluorescent lamp, for example, the luminance according to the observation angle when the prism sheet is provided in FIG. As shown in FIG. 3B, the directivity is obtained as shown in the relationship of the rise rate of the above, and by further stacking two prism sheets 32 so that the directions of the prisms are orthogonal to each other, as shown in FIG. improves. Therefore, by arranging the surface on which the two prism sheets are overlapped so as to be in a direction perpendicular to the transparent plate 2 provided on the upper part of the box body 1, ± 20
Light travels parallel to the transparent plate 2 within a range of about ゜.

In the above-described example, the light source 3 having directivity obtained by the light emitting section 31 and the prism sheet 32 is used. However, the directivity light source 3 can be replaced by, for example, a lamp-type LED without using a prism sheet. Provide a dome-shaped (not a complete dome, a dome extending linearly along the shape of the light-emitting portion) coating layer around the light source, or set a lens having a lens effect to narrow the beam on the front surface. Can also be obtained by

Since the display object 4 does not need to transmit light, it is possible to use a normal poster or the like printed on paper as it is, and attached to the bottom inside the box 1. This attachment may be of a fitting type, a structure of being fixed with a thumbtack, or may be suitably fixed. The display object 4 can be easily replaced by opening or removing the transparent plate 2.

According to the front light type display device of the present invention, the light source is provided on the side surface of the box in front of the display object, and the light from the light source is emitted in a direction parallel to the transparent plate with directivity. Therefore, the amount of light that goes directly to the outside is reduced, and the light traveling toward the transparent plate also has an extremely large incident angle, so that the light is totally reflected by the transparent plate and reflected to the bottom side of the box. Therefore, the display object provided on the bottom surface of the box is efficiently illuminated by the reflected light of the light source, and is displayed brightly. Since this display device performs display by providing a light source on the front side of the display object, there is no need to transmit the conventional backlight on the back side, and a special display panel using a transparent film or the like as the display object is formed. No need. As a result, a display device printed on ordinary paper can be displayed as it is, and a very bright display device like an illuminated signboard can be obtained. The display device can also be used as a very inexpensive display device for an advertising tower or the like.

[0019]

As described above, according to the present invention, a very large display device conventionally used as an electric signboard can be provided.
A display device that can display brightly in color in the same way as an illuminated signboard can be obtained at low cost without using a special display panel and using a display material printed on ordinary paper. As a result, it can be used as a large advertising tower instead of an illuminated signboard.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment of a front light type display device of the present invention.

FIG. 2 is an explanatory diagram of an example of a prism sheet for obtaining directivity of the light source of FIG.

FIG. 3 is a diagram showing directivity characteristics when the prism sheet of FIG. 2 is used.

FIG. 4 is an explanatory diagram of an illuminated signboard as an example of a conventional display device.

FIG. 5 is an explanatory diagram of another configuration example of a backlight such as a conventional illuminated signboard.

FIG. 6 is an example of a display device such as a conventional bulletin board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Box 2 Transparent plate 3 Light source 4 Display object 31 Light emitting part 32 Prism sheet

Claims (2)

[Claims] 1. A box having a transparent plate provided on an upper surface thereof, and a light source provided on at least one side wall of the box and having directivity in a direction parallel to the transparent plate. A front light type display device on which a display object can be provided. 2. The front light type display device according to claim 1, wherein the light source having directivity is a light source having a prism sheet provided in front of a fluorescent tube.