JPH0113163B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a light-transmitting cover disposed over a light projection opening of a lighting fixture to control light from a light source.

[Technical background of the invention]

2. Description of the Related Art A downlight fixture that is used by being embedded in a ceiling surface or the like generally has a cylindrical body, and a light-transmitting cover is provided over the light projection opening.

If the fixture body is square cylindrical and the transparent cover is square plate-shaped, the irradiation pattern emitted from the transparent cover is almost rotationally symmetrical, and multiple lighting fixtures When providing general illumination by arranging a light distribution pattern, there is a risk that dark areas will occur between adjacent light distribution patterns and the degree of uniformity will deteriorate. In addition, to improve symmetry, the spacing between instruments must be narrowed, so the number of instruments must be increased.
This would be uneconomical and go against energy conservation.

For this reason, a light-transmitting cover has been proposed in which a prism is provided to obtain a rectangular light distribution pattern.

For example, as seen in US Pat. No. 3,502,865, there is known a light-transmitting cover in the form of a rectangular plate with a plurality of rectangular prisms arranged concentrically.

This device provides a substantially rectangular light distribution pattern, but since a plurality of rectangular prism sections are provided concentrically, it is possible to obtain light from within the illumination pattern 40 on the floor surface 30 shown in FIG. When looking at the transparent cover, when looking at cover 1 from Figure 8, the first
In the figure, A and B in the same figure appear to be shining.
When the cover is viewed from a further position, the prism parts 2 on both sides of the corner will shine at the same time, causing a sudden change in illuminance, creating bright spots on the floor, and causing uneven illuminance distribution. It turns out that there is something.

[Purpose of the invention]

The present invention has been made in consideration of the above-mentioned circumstances, and it is an object of the present invention to provide a lighting fixture that does not produce bright spots on the floor surface and provides a rectangular illumination pattern with good uniformity.

[Summary of the invention]

In the present invention, a light-transmitting cover disposed over a light emitting opening of a device main body is formed into a rectangular plate shape, and a first prism surface is provided at the center of the plate surface, and a second prism surface is adjacent to the first prism surface. A second prism surface is formed between the outer periphery of the side part and divided into four sections by a plurality of prism parts parallel to the side part, and a second prism surface is formed at the corner part of the plate surface in a direction intersecting the diagonal line of the plate surface. It is characterized in that a third prism surface divided into four sections is formed by a plurality of prism sections.

[Embodiments of the invention]

The details of the present invention will be explained below with reference to the embodiments shown in FIGS. 2 to 6. Reference numeral 11 denotes a device main body, and this device main body 11 has a light projection opening 12 on the lower surface, and can be embedded in a rectangular cylindrical shape, for example, in a ceiling surface. Reference numeral 13 denotes a light source, and this light source 13 is, for example, a high-intensity discharge lamp, which is attached to a socket 14 provided in the appliance body 11 and is connected to the appliance body 11.
It is located in Reference numeral 15 denotes a light-transmitting cover, and this light-transmitting cover 15 is disposed in the light projection opening 12.

As shown in FIG. 3, the light-transmitting cover 15 has a rectangular shape, for example, a square plate shape, and may be made of a transparent plate material such as synthetic resin. The light-transmitting cover 15 is located at the center of the plate surface 16, and includes, for example, a plurality of concentric prism portions 1.
The first prism surface 1 is partitioned into a rectangular shape by 7.
8. Adjacent to each side of the first prism surface 18, a plurality of prism sections 21 parallel to the side 19 are provided between the first prism surface 18 and the center 20 of the side 19 of the plate surface 16. A second prism surface 22 is divided into four sections, and a plate surface 16 is formed at the corner of the plate surface between this second prism surface 22 and the first prism surface 18.
The third prism surface 2 is divided into four sections by a plurality of prism sections 23 extending in a direction intersecting the diagonal line of the third prism surface 2.
4 is formed. Then the first and second
The prism parts 17 and 21 of the prism surfaces 18 and 22 are formed as shown in FIG. 4, and the prism angle is set so that the maximum beam angle α of the light emitted from the light source 13 is about 35°. . Also, the third
The prism portion 23 of the prism surface 24 is formed as shown in FIG. 5, and the prism angle is set so that the maximum beam angle β of the light emitted from the light source 13 is approximately 45°.

Setting the prism sections 17 and 21 of the first and second prism surfaces 18 and 22 to a maximum beam angle of approximately 35 degrees is important.If the maximum beam angle is set to less than 35 degrees, the light directly below the fixture will increase and the uniformity of illuminance will deteriorate. It will drop.
Furthermore, if the maximum beam angle of the prism section 23 of the third prism surface 24 is set to approximately 45 degrees, if the beam angle is set to 45 degrees or more, the light may be emitted at an angle of 60 degrees or more due to problems such as the size of the light source 13. This is because there is an inconvenience that glare may occur.

Next, the operation of this embodiment will be explained.
The light emitted from the light source 13 disposed in the instrument body 11 is controlled by the first, second and third prism surfaces 18, 22, 24 of the transparent cover 15,
The light that has passed through the first and second prism surfaces 18 and 22 has a light distribution shown by the light distribution characteristic curve X in FIG. The light distribution shown by curve Y in FIG. 6 was obtained, the illuminance distribution was also almost uniform, and it was confirmed that no bright spots were generated.

Furthermore, when the transparent cover 15 is viewed from inside the irradiation pattern shown on the floor surface 40 in FIG. 8, and as shown in FIG. At section A', section B' appears to be shining, and the prism section at the corner is formed along the direction that intersects the diagonal line of the board surface, so at point A' and section B', It becomes the C' part of brightness, and sudden changes in illumination do not occur, and bright spots, so-called glare, can be effectively prevented.

Although the present invention has been described with respect to the above embodiments, the present invention is not limited thereto. For example, the first prism surface may be formed of concentric rectangular prism parts. Further, the light-transmitting cover may be formed into a rectangular shape. In this case, the light distribution pattern is rectangular. Even in this case,
The prism surfaces at the corners of the plate surface are required to form prism portions extending in a direction perpendicular to the diagonal line of the plate surface.

Furthermore, even if the device main body is cylindrical, the present invention can be applied as long as the transparent cover is square.
Furthermore, it can be applied not only to recessed type lighting fixtures but also to various types of lighting fixtures such as those that are directly attached to the ceiling.

〔Effect of the invention〕

As described in detail above, according to the present invention, sudden changes in illuminance do not occur at the corners of a rectangular transparent cover, and it is possible to effectively prevent bright spots, so-called glare, and to reduce unevenness in brightness. It can be illuminated with uniform illuminance without any brightness.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the shine in a conventional translucent cover, Fig. 2 is a partially cutaway front view of a lighting fixture showing an embodiment of the present invention, and Fig. 3 is a plan view of the translucent cover as well. , Figure 4 is the same as Figure 3 -
FIG. 5 is an enlarged cross-sectional view along the line V-V in FIG. 3 with a portion omitted, and FIG. 6 is a light distribution curve diagram of the lighting equipment. , FIG. 7 is an explanatory diagram showing the shine in the transparent cover, and FIG. 8 is an explanatory diagram showing the irradiation pattern. 11... Instrument body, 12... Light projection opening, 13...
...Light source, 15... Translucent cover, 18... First prism surface, 22... Second prism surface, 24...
...Third prism surface.

Claims (1)

[Scope of Claims] 1. A device comprising: a device body having a light projection opening on the lower surface; a light source disposed in the device body; and a translucent cover disposed in the light projection opening; The optical cover has a rectangular plate shape, and the first part is located in the center of the plate surface and is formed by multiple prism parts.
a prism surface, and a plurality of prism sections adjacent to each side of the first prism surface and parallel to the side between the first prism surface and the outer periphery of the side, and partitioned into four sections. It is formed of a second prism surface, which has a second prism surface, and a plurality of prism parts extending in a direction intersecting the diagonal of the plate surface at the corner portion of the plate surface between the second prism surface and the first prism surface, and is divided into four sections. A lighting fixture comprising: a divided third prism surface; 2. The lighting device according to claim 1, wherein the first prism surface of the translucent cover is formed of a concentric prism section. 3. Claim 1 or 2, wherein the light-transmitting cover is formed in a regular square shape.
Lighting equipment as described.