|
(11) | EP 1 111 293 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||
| (54) | Ceiling luminaire |
| (57) A ceiling luminaire (1) includes a shade (2) and a light source (12). A recess (11)
having a reflective inner surface is formed at the top of the shade (2) and the light
source (12) is at least partly received in the recess. |
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] This invention relates to a luminaire, and more particularly to a ceiling luminaire with a shade which is suspended from a ceiling by a chain suspender, a direct mounting type suspender or the like.
Description of the Related Art
[0002] There has been in wide use a ceiling luminaire which is provided with a shade, which is of transparent acrylic resin or aluminum and is like a bowl open downward, and is suspended from a ceiling by a chain suspender, a direct mounting type suspender or the like.
[0003] As shown in Figure 3, a typical conventional ceiling luminaire 21 comprises a lamp holder 23 having a built-in socket for a lamp 22 and a shade 24, and is suspended from a ceiling 26 by a chain suspender 25 which is connected to the top of the lamp holder 23. The shade 24 is generally formed of transparent acrylic resin (or aluminum) and is like a bowl open downward. The shade 24 is fixed to the lamp holder 23 at its upper end and is relatively large in diameter (e.g., about 415mm in outer diameter of the lower periphery).
[0005] Such a conventional ceiling luminaire is disadvantageous in that it is relatively low in horizontal illuminance just below it for the size and power of the lamp 22. For example, when a 250W metal halide lamp is employed as the lamp 22, the horizontal illuminance two meters just below the ceiling luminaire is about 500Lx and power consumption becomes tremendous when a large number of such ceiling luminaries are used.
SUMMARY OF THE INVENTION
[0006] In view of the foregoing observations and description, the primary object of the present invention is to provide a ceiling luminaire which can provides high horizontal illuminance just below it even if a relatively low power lamp is employed.
[0007] In accordance with the present invention, there is provided a ceiling luminaire comprising a shade and a light source, wherein the improvement comprises that a recess having a reflective inner surface is formed at the top of the shade and the light source is at least partly received in the recess.
[0008] In this specification, the term " light source" means a light emitting portion itself when a light source comprises a light emitting portion and a bulb enclosing the light emitting portion.
[0009] It is preferred that the light source be wholly received in the recess. Further, when the light source is a lamp comprising a light emitting portion and a bulb, it is preferred that the lamp be wholly received in the recess and the lower end of the recess, at which the recess opens downward, be covered with a transparent protective plate.
[0010] Further it is preferred that the shade be fixed to a lower end portion of a lamp holder provided with a socket for a lamp, and the recess be defined by a reflector fixed in the lamp holder.
[0011] Further it is preferred that the reflective inner surface of the recess be substantially a curved surface such as a spherical surface, a paraboloid, or the like.
[0012] In the ceiling luminaire of this embodiment, the horizontal illuminance just below the ceiling luminaire can be greatly increased by virtue of the recess which has a reflective inner surface and in which the light source is at least partly received. Accordingly, even if a relatively small and relatively low-power lamp is employed as the light source, the ceiling luminaire of this embodiment can provide horizontal illuminance just below it higher than that provided by the conventional ceiling luminaire, thereby reducing power consumption.
[0013] When a lamp of such a small size that it is wholly received in the recess is employed and the lower end of the recess, at which the recess opens downward, is closed by a transparent protective plate such as of reinforced glass, danger of breakage of the lamp can be avoided.
[0014] Further when the reflective inner surface of the recess is substantially a curved surface, light from the light source can be better reflected downward.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015]
Figure 1 is a side view showing a ceiling luminaire in accordance with an embodiment of the present invention,
Figure 2 is an enlarged side view partly in cross-section of the lamp holder, and
Figure 3 is a side view showing a conventional ceiling luminaire.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0016] In Figure 1, a ceiling luminaire 1 in accordance with an embodiment of the present invention is provided with a shade 2 which is flared downward, opens downward and is of prism-finished transparent acrylic resin. A lamp holder 3 which has a lamp 12 and a reflector 10 built therein is fixed to the top of the shade 2. The ceiling luminaire 1 is suspended from a ceiling 5 by a chain suspender 4 which is fixed to the ceiling 5 at its upper end and to the top of the lamp holder 3 at its lower end.
[0017] As shown in Figure 2, the lamp holder 3 comprises a metal casing 6, a bracket 7 which is provided in an upper part of the metal casing 6, and a socket 8 fixed to the bracket 7 directed downward. A ring 9 to which the lower end of the chain suspender 4 is connected is fixed to the top of the casing 6. A reflector 10 of metal whose lower side forms a concave semi-spherical reflective surface is mounted on a lower portion of the casing 6 so that a recess 11 whose inner surface is defined by the reflective surface of the reflector 10 is formed at the top of the shade 2.
[0018] The reflector 10 is provided with an opening 10a at the top thereof, and a lamp 12 in the form of an elongated tube (e.g., 75mm in length) is mounted on the socket 7 through the opening 10a. The lamp 12 may be a known small size ceramic-metal halide lamp or a small size fluorescent lamp, and comprises a transparent glass bulb 12a and a light emitting portion 12b housed in a lower portion of the glass bulb 12a. The lower half of the lamp 12 projects downward into the recess 11 through the opening 10a of the reflector 10 with its lower end held above the lower edge 10b of the reflector 10 and the light emitting portion 12b held in the recess 11.
[0019] A transparent protective plate 13 which may be, for instance, of reinforced glass is removably mounted on the lower edge of the casing 6 to cover the open end of the recess 11 (e.g., about 100mm in diameter). The shade 2 is removably mounted on the lamp holder 3 by fittings 14 and 15 and a decorative screws 16.
[0020] In the ceiling luminaire 1 of this embodiment with an arrangement described above, the light source becomes like a point source and a high reflective efficiency is obtained since the light emitting portion 12b of the lamp 12 is disposed in the recess 11 having a reflective inner surface, whereby the ceiling luminaire 1 of this embodiment can provide greatly increased horizontal illuminance just below it.
[0021] For example, when a 70W small size ceramic-metal halide lamp was employed as the lamp 12, the horizontal illuminance two meters just below the ceiling luminaire 1 of this embodiment was 1800Lx which was drastically higher than that obtained by the conventional ceiling luminaire and power consumption was reduced to about a quarter of that for the conventional ceiling luminaire.
[0022] Further, since the lamp 12 may be of such a size that the lamp 12 can be holly received in the recess 11, the recess 11 may be closed by the protective plate 13, which improves safety.
[0023] Though, in the embodiment described above, the light emitting portion 12a of the lamp 12 is completely received in the recess 11, which is preferable from the viewpoint of reflective efficiency, the light emitting portion 12a may project downward from the recess 11. In such a case, the protective plate 13 may be eliminated or may be arranged to project downward. Further, though, in the embodiment described above, the reflector 10 has a semi-spherical reflective surface, the reflective surface of the reflector 10 may be of other various shapes such as a paraboloid or may be a substantially curved surface formed by a number of facets.
[0024] Further, though, in the embodiment described above, the shade 2 is formed of prism-finished transparent acrylic resin, the shade 2 may be formed of aluminum.
1. A ceiling luminaire comprising a shade and a light source, wherein the improvement
comprises that a recess having a reflective inner surface is formed at the top of
the shade and the light source is at least partly received in the recess.
2. A ceiling luminaire as defined in Claim 1 in which the light source is wholly received
in the recess.
3. A ceiling luminaire as defined in Claim 2 in which the light source is a lamp and
the lamp is wholly received in the recess and the lower end of the recess is covered
with a transparent protective plate.
4. A ceiling luminaire as defined in any one of Claims 1 to 3 in which the shade is fixed
to a lower end portion of a lamp holder provided with a socket for a lamp as the light
source, and the recess is defined by a reflector fixed in the lamp holder.
5. A ceiling luminaire as defined in any one of Claims 1 to 3 in which the reflective
inner surface of the recess is substantially a curved surface.
6. A ceiling luminaire as defined in Claim 4 in which the reflective inner surface of
the recess is substantially a curved surface.