JPH0643832Y2 - Surface lighting device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a surface illuminating device for illuminating a translucent display body from the back side, which is used for an illuminated sign, an induction display lamp and the like. .

[Prior Art] A conventional surface illumination device is shown in FIG. This surface lighting device
This is a so-called edge light system in which a display body (not shown) is indirectly illuminated by using a light guide body 2 formed of a transparent material. In this surface illuminating device, a plurality of straight tube-shaped lamps 1 are arranged along both longitudinal directions of both end faces of the light guide 2, and a diffusion plate 3 for diffusing light emitted from the light guide 2. Is equipped with.

In this surface lighting device, the light guide 2 emits light from the lamps 1 incident from both end surfaces, and the light emitted from the light guide 2 is diffused by the diffusion plate 3 and arranged in front of the diffusion plate 3. The translucent display body (not shown) is illuminated from the back side.

[Problems to be Solved by the Invention] Generally, since the display body is often longer than the length of the lamp 1, the incidence of the light guide 2 having the same size as the display body as shown in FIG. It is necessary to arrange a plurality of lamps 1 along the longitudinal direction of the end face. However, in this case, there is a problem that the joint portion of the lamp 1 of the light guide 2 becomes dark. The darkened portion is shown by a shaded portion a in FIG. 7 (a).

Therefore, in the above-mentioned case, it is possible to use one lamp 1, but there are various shapes of the display body depending on the application etc., and each lamp 1 is manufactured with a dedicated length. Is difficult. Moreover, when the lamp 1 is a discharge lamp such as a fluorescent lamp, if the length is extremely long, the discharge becomes unstable and the luminous efficiency is lowered.

The present invention has been made in view of the above points, and an object of the present invention is to provide a surface lighting device capable of illuminating a display body with uniform brightness using a lamp for general use that is shorter than the length of the display body. To do.

[Means for Solving the Problems] In order to achieve the above object, the present invention arranges a light source in such a manner that the central portion of the light source on the other end surface side is located at the joint portion of the light source on the one end surface side of the light guide. , A plurality of thin plate-shaped light guide plates that diffuse the light incident from one end face to the side opposite to the incident end face and uniformly emit the light are stacked and guided along the longitudinal direction of the light source. An optical body is formed, and at least the incident end faces of a plurality of light guide plates in the joint portion of the light source are made to face the light source on the reflection side.

[Operation] As described above, according to the present invention, by arranging the light source in such a manner that the central portion of the light source on the other end surface side is located at the joint portion of the light source on the one end surface side of the light guide body, The light from the light source on the other end side can be used to emit light from the joint part of the light source on the other side, and the light incident from one end surface is diffused while being guided to the side opposite to the incident end surface. A light guide is formed by stacking a plurality of thin light guide plates that emit light uniformly over the entire length of the light source along the longitudinal direction of the light source. The light guide plate located at the seam of the light source and having the incident end surface facing the light source on the opposite side efficiently guides the light of the light source on the other end surface to the seam of the light source on the one end surface. Allows the commonly used run to be shorter than the length of the display. It is possible to illuminate the display body with a uniform brightness by using a light source such as a lamp.

[Embodiment] In this embodiment, the light guide 2 is formed by laminating a plurality of thin light guide plates 4 as shown in FIG.

As shown in FIG. 2, the light guide plate 4 has a substantially right triangle when viewed from the side, and each surface is formed to be a smooth surface except the lower surface 4B, and the lower surface 4b is, for example, white coated on the outer surface to diffuse. As a reflective surface. A reflector may be attached to the lower surface 4b in close contact. In this light guide plate 4, the wide end surface 4a is used as the incident surface, and the curved upper surface 4c is used as the emitting surface. The light guide plate 4 is formed of a transparent material having a refractive index of 1.4 to 1.6 such as glass or plastic, and the light incident from the end face 4a is totally reflected by the smooth surface. In addition, the upper 4c is the lower surface of the incident light from the end face 4a.
It is formed on a curved surface with a curvature that reflects uniformly on 4b, and end face 4a
It also functions as a reflection surface that guides the incident light from the side toward the end face 4d. Further, although the end surface 4d is provided on the side opposite to the end surface 4a which is the incident surface in the present embodiment, the end surface 4d may have a pointed shape without the end surface 4d.

In the light guide 2, as shown in FIG. 1, the directions of the end faces 4a, which are the incident faces of the light guide plates 4 adjacent to each other, are alternately reversed,
It is formed by stacking a plurality of light guide plates 4, and both end faces where the end faces 4a of the light guide plates 4 are arranged in a row serve as an incident face 2a on which the light of the lamp 1 is incident.

A diffusion plate 3 is arranged above the light guide 2 as shown in FIG. The diffusing plate 3 may be made of, for example, a milky white resin, or may be frosted glass.

In this embodiment, the light of the lamp 1 incident from the end face 4a of the light guide plate 4 is guided to the end face 4d side by total reflection of the upper face 4c and the like, and the lower face 4b which is a diffuse reflection face and the direct light from the lamp 1 Light reflected from the upper surface 4c and the like is diffused, and the entire light guide plate 4 emits light uniformly. Then, of the light diffusely reflected by the lower surface 4b, light having a critical angle of the upper surface 4c or less passes through the upper surface 4c and reaches the diffuser plate 3, and the diffuser plate 3 diffuses the light from the upper surface 4c and makes it uniform. Light is obtained, and the display plate can be uniformly illuminated from the back side. When the light guide 2 is formed by stacking a plurality of light guide plates 4 in this manner, the number of light guide plates 4 to be stacked can be increased even if the display 1 has various shapes with different lengths in the longitudinal direction of the lamp 1. By changing it, it is possible to easily form the light guide 2 according to the length of the display body.

As shown in FIG. 3 (a), the plurality of lamps 1 are arranged in parallel along the longitudinal direction of each incident surface 2a of the light guide 2.
The lamp 1 on the one incident surface 2a side of the light guide 2 and the other incident surface
The position of the lamp 1 on the 2a side is displaced by half the lamp length. By doing so, the light of the light-incident portion of the lamp 1 on the one incident surface 2a, that is, the joint portion of the lamp 1 can be guided to the light of the brightest portion of the lamp 1 on the other incident surface 2a side. . Moreover, since the end faces 4a, which are the incident surfaces of the light guide plates 4 adjacent to each other, are alternately formed so as to face each other, the plurality of light guide plates 4 are laminated to form the other incident surface.
The light of the highest brightness portion of the lamp 1 on the 2a side can be efficiently guided to the joint portion of the lamp 1 on the one incident surface 2a side. That is, in the light guide 2 formed of a single member as in the conventional case, the light from the other incident surface 2a diffuses relatively uniformly over the entire light guide plate 2, so that the lamp 1 on the one incident surface 2a side is It was difficult to efficiently guide the light of the lamp 1 to the joint portion, but if the light guide 2 is composed of a plurality of light guide plates 4 as in the present embodiment, it is incident from the end face 4a. Light is the light guide plate 4
It is possible to uniformly emit light by itself and reduce the light diffused to the adjacent light guide plate 4 side. Therefore, the light of the lamp 1 can be efficiently guided to the joint portion of the lamp 1, and the uneven brightness can be reduced.

By the way, the light guide plates 4 forming the light guide 2 may be arranged as follows. That is, as shown in FIG. 5, the end face 4d of all the light guides 4 in this portion is connected to the joint portion of the lamp 1.
Alternatively, the brightness of the joint portion of the lamp 1 may be increased, and the arrangement of the light guide plates 4 may be appropriately adjusted to other states to uniformly illuminate the display body.

Further, the light guide plate 4 shown in FIGS. 6A to 6C may be used.

The light guide plate 5 in FIG. 6 (a) is the upper surface 4c of the light guide plate 4 in FIG.
The lower surface 4b and the lower surface 4b are inverted, and the upper surface 5c is a smooth surface except the upper surface 5c, and the upper surface 5c is a diffuse transmission surface. Bottom surface 5b
Like the upper surface 4c of the light guide plate 4, the end surface 5a is formed into a curved surface having a curvature that uniformly reflects the incident light from the end surface 5a to the upper surface 5c.
The light incident from is totally reflected. Also,
The upper surface 5c is a diffusion / transmission surface by, for example, frosting. A reflection plate may be closely attached to the lower surface 5b, or aluminum may be vapor-deposited to make the lower surface 5b a complete total reflection surface.

In this light guide plate 5, the light of the lamp 1 incident from the end surface 5a is guided to the end surface 5d side by the reflection of the lower surface 5b and the like, and the direct light from the lamp 1 and the lower surface 5b and the like from the upper surface 5c which is a diffuse transmission surface. The reflected light is diffused and transmitted, and the entire light is emitted uniformly.

The light guide plate 6 shown in FIG. 6 (b) is formed of a transparent material into a rectangular parallelepiped thin plate, and each surface is formed as a smooth surface. In this light guide plate 6, an opacifying agent 7 as a diffusing agent for diffusing the light of the lamp 1 is mixed inside, and the opacifying agent 7 is applied from the end surface 6a on which the light of the lamp 1 is incident to the opposite end surface 6d. The amount of mixing is increased as it goes, and the diffusivity is increased as it goes to the end face 6d side. The light guide plate 6 also uses the upper surface 6c as an emission surface. The lower surface 6b may be subjected to a reflection treatment such as aluminum vapor deposition. This light guide plate 6 also guides the light of the lamp 1 incident from the end surface 6a to the end surface 6d side by reflection on each surface,
The opacifying agent 7 diffuses the light to cause the light guide plate 6 to uniformly emit light, and uniform light can be obtained from the upper surface 6c.

The light guide plate 8 of FIG. 6 (c) has substantially the same shape as the light guide plate 5 of FIG. 6 (a), and the lower surface 8b of the light guide plate 8 is processed into a Fresnel shape. Different from The bottom surface
The 8b is subjected to a reflection treatment such as aluminum vapor deposition to enhance light diffusion.

[Advantage of the Invention] As described above, according to the present invention, the light source is arranged such that the central portion of the light source on the other end surface side is located at the joint portion of the light source on the one end surface side of the light guide body. The light from the light source on the other end surface can be used to emit light from the joint portion of the light source on the one end surface, and the light incident from the one end surface is diffused while being guided to the side opposite to the incident end surface. A plurality of thin light guide plates that emit light uniformly over the entire surface to form a light guide body by stacking them along the longitudinal direction of the light source, and at least the light-incident end faces of several light guide plates at the seam of the light source are opposite to each other. Since the light guide plate is located at the seam of the light source and has the incident end face facing the light source on the opposite side, the light from the light source on the other end face is efficiently connected to the light source on the one end face. Light sources such as commonly used lamps that can guide light to, and are therefore shorter than the length of the display There is an effect that the display body can be illuminated by using the. Moreover, by stacking a plurality of light guide plates along the longitudinal direction of the light source to form the light guide body, the light guide plates are laminated even for display bodies of various shapes having different lengths in the longitudinal direction of the lamp. There is also an effect that the light guide body can be easily formed according to the length of the display body by simply changing the number of sheets.

[Brief description of drawings]

FIG. 1 is a perspective view of a light guide according to an embodiment of the present invention, FIG. 2 is a perspective view of the same light guide plate, and FIG. 3 (a) is a plan view showing the arrangement of the same lamp. Figure (b) shows A- in Figure (a).
A'cross-sectional view, FIG. 4 is an explanatory view of the same light emitting state, FIG. 5 is a plan view showing a light guide body in which the arrangement of light guide plates is changed, and FIGS. 6 (a) to 6 (c) are different shapes. 7A is a plan view of the conventional example, and FIG. 7B is a plan view of FIG. 7A.
FIG. 9 is a sectional view taken along line AA ′ of FIG. 1 is a lamp, 2 is a light guide, 4 to 6 and 8 are light guide plates, and 4a to 6a and 8a
Is the end face.

Claims (1)

[Scope of utility model registration request] 1. A surface illuminating device for arranging a plurality of linear light sources in parallel along both end faces of a light guide, and illuminating a translucent display with the light of the light guide emitted by the light sources. , The light source is arranged so that the central portion of the light source on the other end surface side is located at the joint portion of the light source on the one end surface side of the light guide, and the light incident from the one end surface is guided to the side opposite to the incident end surface. While forming a light guide by laminating a plurality of thin plate-shaped light guide plates that diffuse and uniformly emit light, the light guide plate is formed at least at the joints of the light sources. A surface lighting device in which an end surface faces a light source on the opposite side.