JP2731221B2 - Surface lighting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface illuminating device that is used for an electric sign, a guidance display lamp, and the like, and illuminates a translucent display body from the back side. .

[Prior Art] FIG. 6 shows a conventional guidance indicator. The guide indicator light reflects the light of the lamp 1 housed in the main body 5 by using the reflection plate 7 and irradiates the light to the display body 6, so that the light transmitting property attached to both open side surfaces of the main body 5 is improved. This is for illuminating the display body 6.

However, in such a conventional guide indicator lamp, it is necessary to keep a certain distance between the lamp 1 and the display unit 6 in order to make the luminance of the display surface of the display unit 6 uniform. Therefore, there was a problem that the thickness of the device was increased.

In order to solve the above problem, an edge light type surface illumination device shown in FIG. 7A has been proposed. This surface lighting device indirectly illuminates the display 6 using the light guide 2 formed of a transparent material, and as shown in FIG. And the lamp 1 is disposed along the lower end surface of the light guide 2,
The light from the lamp 1 incident from the lower end surface of the light guide 2 is guided to the upper end surface side of the light guide 2 and the incident light is diffused on the back surface of the light guide 2 subjected to the diffusion processing. , Light guide 2
Are substantially uniformly emitted, and the display 6 is uniformly illuminated with light emitted from the front surface of the light guide 2.

[Problem to be Solved by the Invention] However, even if such an edge light type surface illumination device is used, there is a certain limit in reducing the thickness of the fixture. That is, in the edge light type surface illuminating device, there is a limit in reducing the thickness of the light guide 2 according to the area of the display body 6 that uniformly illuminates, and therefore, as shown in FIG. If there are 6 on each side, each display 6
In order to illuminate the light source, the light guide plate 2 is required, and there is a problem that the thickness of the device is almost double as compared with the case where the display body 6 is provided only on one side.

The present invention has been made in view of the above points, and an object of the present invention is to provide a surface illumination device that can reduce the thickness of an appliance even when used in an appliance having a display body on both sides. It is in.

[Means for Solving the Problems] In order to achieve the above object, the present invention diffuses light incident from one end face which is an incident face while guiding the light to the opposite side to the incident end face to uniformly diffuse the light. A plurality of thin light guide plates that emit light and emit light from an emission surface that is one end surface adjacent to the incidence surface are made to have the same orientation of the incidence surfaces and alternately the orientations of the emission surfaces of the light guide plates adjacent to each other. A light guide formed by stacking the light guides opposite to each other, and a linear light source arranged in parallel with the surface on which the light-incident surface of the light guide plate is aligned in the longitudinal direction in the stacking direction of the light guides. ing.

[Operation] As described above, according to the present invention, the light incident from one end surface, which is the incident surface, is diffused while being guided to the side opposite to the incident end surface, and the light is uniformly emitted as a whole. A light guide is formed by stacking a plurality of thin light guide plates that emit light from an exit surface, which is an end surface, with the directions of the incident surfaces coincided and the directions of the exit surfaces of the adjacent light guide plates are alternately reversed. By forming the body, the thickness of the light guide plate is increased so that a uniform light can be emitted from the emission surface of each light guide plate even with a thickness substantially equal to the diameter of the lamp. The thickness is almost the same as the diameter of the lamp.

Example In the present example, the light guide 2 is formed by laminating a plurality of thin light guide plates 4 as shown in FIG.

As shown in FIGS. 2 and 4, the light guide plate 4 is a substantially right triangle when viewed from the side, and each surface is formed as a smooth surface except for the front surface 4c, and the front surface 4c is subjected to, for example, frost processing. Formed on the diffuse transmission surface. In this light guide plate 4, the lower surface 4a
Is used as an entrance surface, and the front surface 4c is used as an exit surface. The light guide plate 4 is made of a transparent material having a refractive index of 1.4 to 1.6, such as glass or plastic.
Light incident from the lower surface 4a is totally reflected by a smooth surface. Here, the back surface 4b of the light guide plate 4 is formed into a curved surface having a curvature that uniformly reflects incident light from the lower surface 4a to the front surface 4c. It should be noted that a reflection plate may be closely attached to the back surface 4b, or aluminum may be vapor-deposited on the back surface 4b.
May be a perfect total reflection surface. Although the light guide plate 4 of the present embodiment has the upper end surface 4d, the light guide plate 4 may have a sharp shape without the upper end surface 4d.

As shown in FIG. 3, the light guide 2 is formed by stacking a plurality of light guide plates 4 with the directions of the lower surfaces 4a coincided with each other and the directions of the front surfaces 4c of the adjacent light guide plates 4 are alternately reversed. It is formed. The light guide plate 4 may be laminated by bonding, or may be simply mechanically bonded and laminated.

As shown in FIG. 1, the light guide plate 2 is housed in a main body 5 in which a display body 6 is attached to openings on both sides, and the longitudinal direction of the light guide plate 2 is aligned with the lamination direction of the light guide plate 2. The straight tubular lamp 1 is housed in the main body 5 in such a manner that the lower surfaces 4a are arranged side by side on the side where the rows are arranged. Here, the display body 6 has been subjected to a diffusion process to diffuse light from the light guide plate 2. Note that a diffusion plate may be provided between the display 6 and the light guide plate 2. As described above, in this embodiment, the light guide 2 is constituted by the plurality of light guide plates 4, and the plurality of light guide plates 4 are stacked with the front surfaces 4 c of the light guide plates 4 adjacent to each other being alternately reversed. Therefore, with respect to each light guide plate 4, even if the thickness D 'is almost the same as the diameter of the lamp 1, uniform light can be emitted from each front face 4c. The thickness D (= D ') of the light guide 2 can be made substantially the same as the diameter of the lamp 1, and the thickness of the device can be reduced. Moreover, if the direction of the front surface 4c of the light guide plate 4 is made to coincide with one direction, it is possible to provide a surface illumination device for an appliance having a display body only on one side. Furthermore, since the light guide 2 is formed by laminating a plurality of light guide plates 4, the number of light guide plates 4 to be stacked can be varied even in the case of variously shaped displays having different lengths in the longitudinal direction of the lamp 1. , The light guide 2 corresponding to the display can be easily formed.

Further, as the light guide plate 4, the one shown in FIGS. 5 (a) to 5 (c) may be used.

The light guide plate 8 in FIG. 5A is a front surface 4c of the light guide plate 4 in FIG.
The rear surface 8b has a shape in which the rear surface 4b is inverted and has a smooth surface except for the rear surface 8b. The rear surface 8b is, for example, a white paint applied to the outer surface to be a diffuse reflection surface. In the light guide plate 8, the lower surface 8a is used as an incident surface, and the curved front surface 8c is used as an output surface. Here, similarly to the rear surface 4b of the light guide plate 4, the front surface 8c is formed into a curved surface having a curvature that uniformly reflects the incident light from the lower surface 8a to the rear surface 8b, and the light incident from the lower surface 8a is formed on the rear surface 8b side. It also functions as a reflection surface that leads to light. When the light guide plate 8 is used, the diffusion plate 9 is arranged in front of the front surface 8c.

In the light guide plate 8, the light of the lamp 1 incident from the lower surface 8a is guided to the upper surface 8d by total reflection of the front surface 8c and the like, and the direct light from the lamp 1 and the front surface 8c and the like are reflected on the rear surface 8b which is a diffuse reflection surface. The light reflected from the light guide plate 8 is diffused, and the light guide plate 8 emits light uniformly. Then, of the light diffusely reflected by the back surface 8b, light having a critical angle equal to or less than the critical angle of the front surface 8c is transmitted through the front surface 8c and diffused.
The light from the front surface 8c is diffused by the diffusion plate 9 to obtain uniform light.

The light guide plate 10 in FIG. 5 (b) is made of a transparent material and formed in a rectangular parallelepiped thin plate, and each surface is formed as a smooth surface.
In the light guide plate 10, an opacifying agent 11 as a diffusing agent for diffusing the light of the lamp 1 is mixed therein, and the opacifying agent 11 is transferred from the lower surface 10a where the light of the lamp 1 is incident to the upper surface 10d on the opposite side. The mixing amount increases as the distance increases, and the diffusivity increases as the distance increases toward the upper surface 10d. The light guide plate 10 also uses the front surface 10c as an emission surface. The back surface 10b may be subjected to a reflection treatment such as aluminum evaporation. This light guide plate 10 also allows the light of the lamp 1 incident from the lower surface 10a to be reflected by the respective surfaces so that the upper surface 10d.
The light guide plate is guided to the side, and the light is diffused by the opacifier 11.
10 is made to emit light uniformly, and uniform light is obtained from the front surface 10c.

The light guide plate 12 shown in FIG. 5C has substantially the same shape as the light guide plate 4 shown in FIG. 2. The light guide plate 12 differs from the light guide plate 4 in that the rear surface 12b is processed into a Fresnel shape. The back 12
b is subjected to a reflection treatment by aluminum evaporation or the like to increase the light diffusivity.

[Effects of the Invention] As described above, according to the present invention, light incident from one end surface which is an incident surface is diffused while being guided to the opposite side to the incident end surface to emit light uniformly as a whole, and is adjacent to the incident surface. A plurality of thin plate-shaped light guide plates that emit light from the emission surface that is one end surface are made to accumulate while aligning the directions of the incidence surfaces and alternately stacking the directions of the emission surfaces of the light guide plates adjacent to each other. Since the light guides are formed, the thickness of the light guide plate is such that the light emission surface can be uniformly illuminated even with a thickness substantially equal to the diameter of the light source such as a lamp. The thickness can be made substantially the same as the diameter, which has the effect of reducing the thickness of the device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, FIG. 2 is a perspective view of the above light guide plate, FIG. 3 is a perspective view of the above light guide, and FIG. FIGS. 5 (a) to 5 (c) are explanatory views of light guide plates having different shapes, FIG. 6 is a cross-sectional view of a conventional example, and FIGS. 7 (a) and 7 (b) show a display body on one side or both sides. It is sectional drawing of another conventional example provided with. 1 is a lamp, 2 is a light guide, 4, 8, 10, 12 are light guide plates, 4a, 8a, 1
0a and 12a are lower surfaces, and 4c, 8c, 10c and 12c are front surfaces.

Claims (1)

(57) [Claims] 1. A light incident from one end surface, which is an incident surface, is diffused while being guided to a side opposite to the incident end surface to uniformly emit light as a whole, and from an exit surface, which is one end surface adjacent to the incident surface. A light guide formed by laminating a plurality of thin light guide plates that emit light, matching the directions of the incident surfaces and alternately stacking the directions of the emission surfaces of the adjacent light guide plates, A surface illumination device comprising: a linear light source in which the longitudinal direction is aligned with the laminating direction of the light guides and the light incident surface of the light guide plate is arranged side by side.