JPH0239281Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a surface illumination device using rod-shaped fluorescent lamps.

[Conventional technology]

2. Description of the Related Art A lighting device is known that includes a linear light source, a light receiving plate that covers the front of the linear light source, and a reflecting mirror that is arranged behind the linear light source and receives light from the linear light source and reflects it toward the light receiving plate. The linear light source of such a lighting device is a rod-shaped fluorescent lamp, and the light receiving plate is constituted by a diffuser plate (fogged glass or the like) that diffuses the light in order to obtain the effect of surface illumination.

In such a surface illumination device, in order to uniformly illuminate the surface of the light receiving plate, a reflecting mirror can be provided on the light receiving plate to provide a uniform distribution of reflected light flux.
The three-dimensional shape of such a reflecting mirror can be designed using a computer.

[Problem that the invention attempts to solve]

In order to increase the area of the surface illumination device described above, it is necessary to arrange a plurality of illumination units having a linear light source, a light receiving plate, and a reflecting mirror in a plane.

In this case, in the direction perpendicular to the longitudinal direction of the linear light source, the distribution of the luminous flux reaching the light receiving plate can be made uniform by controlling the luminous flux using a reflecting mirror. Since it is dark near the electrodes, simply arranging the illumination units longitudinally adjacent to each other does not provide the illumination device with a uniform luminous intensity distribution over its entire length.

The present invention aims to solve such problems in surface illumination devices and to obtain a surface illumination device having a uniform luminous intensity distribution over the entire surface.

[Means for solving problems]

In the present invention, a plane partition mirror is provided in which the dark discharge electrode portion of the linear light source is placed outside the reflection area of the reflection mirror at the longitudinal end of each of the illumination units arranged adjacent to each other in the longitudinal direction. It supports both ends of the linear light source.

[Effect]

This eliminates darkness at the longitudinal end of each adjacent illumination unit, and provides a surface illumination device having a uniform luminous intensity distribution in the longitudinal direction of the linear light source.

〔Example〕

FIG. 1 shows an example of a lighting unit used in the present invention. This lighting unit 1 has a mounting board 2, and a reflecting mirror 4 having a rectangular planar shape is fixed between side plates 3, 3 fixed on the board 2. The reflecting mirror 4 has a substantially groove-shaped concave shape, and a linear light source L made of a fluorescent lamp is provided in front of the central portion of the reflecting mirror 4.

Plane partition mirrors 5, 5 are provided at both ends in the longitudinal direction of the reflection mirror 4, and these partition mirrors are fixed to the side plates 3, 3 to form a rectangular frame. The plane partition mirrors 5, 5 serve as means for supporting both ends of the linear light source L, and place the dark discharge electrode L' at the end of the linear light source L outside the reflection area of the reflecting mirror 4.

The side plates 3, 3 can have approximately the same height as the highest parts of both end edges of the reflective mirror 4, and also have the same height as the plane partition mirrors 5, 5. And side plates 3, 3 and partition mirror 5,
A light diffusing plate 6 is attached to the edge portion of 5 . Thereby, the light diffusing plate 6 covers the front side of the linear light source L. The light diffusing plate 6 is made of frosted glass, for example. As a result, the light from the light source L is reflected by the reflecting mirror 4 and reaches the light diffusing plate 6,
The light diffusing plate 6 is made to emit light.

The three-dimensional shape of the reflecting mirror 4 is designed so that the reflected light reaches the light diffusing plate 6 with a uniform luminous flux distribution.
In the example of FIG. 2, the light from the light source L is transmitted to the reflection mirror 4 within an arbitrary virtual plane perpendicular to the longitudinal direction of the light source L.
The light is sequentially reflected toward the outside in the left-right direction, and the light is reflected toward the outermost side at the central raised portion 4a of the mirror 4. In the example shown in FIG. 2, the central raised portion 4a sends the luminous flux toward the outside where it is most likely to become dark, so that a uniform luminous flux distribution can be obtained.

In the example shown in FIG. 3, the reflecting mirror 4 is designed so that the reflected light is directed inward toward the outside, and the reflected light beams intersect in the middle.

In this way, the reflected light flux distribution within the plane orthogonal to the linear light source L can be made uniform by designing the shape of the reflection mirror 4 using a computer.

A plurality of lighting units 1 having the above configuration are arranged side by side in order to increase the illumination area of the lighting device, but in this case, the luminous flux distribution in the direction perpendicular to the longitudinal direction of the linear light source is Since the light intensity is uniform, if the side plate 3 is formed extremely thin, the illumination device will have uniform luminous intensity as a whole.

On the other hand, between illumination units adjacent to each other in the longitudinal direction of the linear light source L, the dark discharge electrodes at the ends of the linear light source are outside the reflection area, so the lighting device similarly has a uniform luminous intensity distribution in the longitudinal direction of the linear light source. It becomes like this. Incidentally, the lighting units adjacent to each other in the longitudinal direction are installed with their positions shifted so as to prevent interference of the protruding discharge electrode portions L'.

If the light source L and the light diffusing plate 6 are very close to each other, the amount of light directly reaching the light diffusing plate 6 from the light source L will be large and it will appear brighter in that area. As shown in FIG. 7, a light flux adjusting device A can be provided between the light source L and the light diffusing plate 6. In the example of FIG. 4, the light flux adjustment device A is a semi-cylindrical transparent Fresnel plate, and in the example of FIG. 5, it is a flat transparent Fresnel plate. Note that Fresnel surfaces may be formed on both sides. The Fresnel surface adjusts the luminous flux distribution of the light from the light source before it reaches the light diffusing plate 6. In the example of Figures 6 and 7,
The light flux adjusting device A is a partial light shielding film, in the case of Fig. 6 a light shielding film printed on the circumferential surface of a fluorescent lamp is used, and in the case of Fig. 7 a planar light shielding film is used. .

[Effect of idea]

In the present invention, the illumination unit is constructed by providing flat partition mirrors at both ends of the linear light source that cross the longitudinal direction of the linear light source consisting of a fluorescent lamp inside the discharge electrode section to eliminate the influence of the dark discharge electrodes at both ends. A plurality of illumination devices arranged adjacent to each other can have uniform luminous intensity in the longitudinal direction of the linear light source.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an example of a lighting unit used in the present invention, Fig. 2 is a sectional view thereof, Fig. 3 is a view similar to Fig. 2 showing another example, and Figs. 4 to 7 are luminous flux. FIG. 3 is a cross-sectional view showing different examples of adjustment devices. L: rod-shaped fluorescent lamp, L': discharge electrode portion of fluorescent lamp, 3: side plate, 4: reflective mirror, 5: plane partition mirror, 6: light diffuser, A: luminous flux adjustment device.

Claims (1)

[Scope of utility model registration request] A plurality of light sources including a linear light source made of a rod-shaped fluorescent lamp, a light diffusing plate that covers the front of the linear light source, and a reflecting mirror placed behind the linear light source that receives light from the linear light source and reflects it toward the light diffusing plate. This is a surface illumination device constructed by consecutively arranging rectangular illumination units at least in the longitudinal direction of the linear light source, and the reflecting mirror of each illumination unit reflects the light received from the linear light source in the longitudinal direction of the linear light source. The illumination unit has a groove-shaped concave shape with a geometric shape that reflects the light so that a uniform luminous flux distribution can be obtained on the surface of the light diffusing plate with respect to any orthogonal virtual plane, and the illumination unit has a linear light source that extends in the longitudinal direction of the light source. Each of the adjacent illumination units is provided with a plane partition mirror in a direction perpendicular to the longitudinal direction, which places the dark discharge electrode portion at the longitudinal end of the linear light source outside the reflection area of the reflection mirror. A surface lighting device characterized in that both ends of a linear light source are supported.