A luminaire includes a light-emitting unit, a main body frame, a support frame, and a lighting unit. The light-emitting unit mounts light-emitting elements. The main body frame supports the light-emitting unit, and is formed rectangular having a hook-shaped engaging piece on one side. The support frame is formed rectangular surrounding the outer periphery of the main body frame, and has a groove-shaped receiving place to engage with the engaging piece of the main body frame, on one internal side. The lighting unit turns on the light-emitting elements.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Applications No. 2008-311217, filed Dec. 5, 2008; No. 2008-311418, filed Dec. 5, 2008; No. 2008-332886, filed Dec. 26, 2008; No. 2008-334065, filed Dec. 26, 2008; and No. 2008-334444, filed Dec. 26, 2008, the entire contents of all of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a luminaire using a light-emitting element such as a light-emitting diode as a light source.

2. Description of the Related Art

A light-emitting diode has been increased in the light-emitting efficiency, and used as a light source. A lighting apparatus using a light-emitting diode as a light source has been commercialized as a relatively large lighting apparatus for home and office use. Jap. Pat. Applin. KOKAI Publication No. JP2008-257903 discloses a lighting apparatus comprising square panels having light-emitting diodes arranged in a checkered pattern on a ceiling. Jap. Pat. Applin. KOKAI Publication No. JP2002-117705 discloses a lighting apparatus, in which a main unit is recessed in a ceiling. This lighting apparatus comprises a main unit recessed and fixed to a ceiling, and a panel-like light source unit fixed to the side frame of the main unit with a hinge having a rod. The light source unit comprises a large number of white light-emitting diodes. Jap. Pat. Applin. KOKAI Publication No. JP2001-005409 discloses a displaying apparatus, in which a large number of displaying units using light-emitting diodes as a light source is recessed in the ceiling of arcade.

The above lighting apparatuses are reduced in weight by making a main body a thin panel by using a light-emitting diode as a light source. Since the installation operation of the lighting apparatus on a′ ceiling is required to perform in high places, the operation is difficult. Therefore, it is important to simplify the installation operation. Further, in the lighting apparatus disclosed in Jap. Pat. Applin. KOKAI Publication No. JP2008-257903, as described in paragraph [0011], the panels are installed on the ceiling by using a fixing means such as a screw, which must be removed on maintenance. Thus, the installation operation includes troublesome steps, and the lighting apparatus may not be securely installed.

As for the lighting apparatus shown in Jap. Pat. Applin. KOKAI Publication No. JP2002-117705, according to the description of paragraph [0007] and [0008], the main unit is fixed to a edge of opening on a ceiling by a common method using the elasticity of spring material. Thus, if the main unit assembled with a lighting unit is very heavy, the lighting apparatus may not be securely installed. Particularly, if the lighting apparatus is very large, the equipment may not be supported by sufficient strength. When the equipment is installed on a ceiling, the equipment is fixed to the edge of opening on the ceiling in the state in which the panel-shaped light source unit is previously fixed to the main unit. The installation operation is difficult, because the operation must be performed while supporting a relatively heavy part such as the light-emitting unit. Though a light-emitting diode is adopted as a light source, workability is not improved. Therefore, improvement of the installation operation is required.

Generally, a large-size lighting apparatus uses a large number of light-emitting diodes. A large number of lead wires connecting the light-emitting diodes to a power supply unit are liable to complexly extend. Therefore, it is important that how to connect the lead wires, how to prevent interference between a light-emitting diode and a light source unit, and how to prevent breaking of wire. In the lighting apparatus disclosed in Jap. Pat. Applin. KOKAI Publication No. JP2001-005409, according to the description of paragraph [0007], a large number of lead wires are connected in vertical and horizontal directions. The electrical wires and lead wires of the light-emitting diodes are exposed to the rear side of the light-emitting unit And disturb the installation of the lighting apparatus. Something may contact and damage or break the electrical wires. Owing to the structure, this lighting apparatus is difficult in reducing the size, and the workability in installation is not improved.

Further, in the lighting apparatus described in Jap. Pat. Applin. KOKAI Publication No. JP2001-005409, according to paragraphs [0021] and [0022], two or more panel-shaped lighting units are arranged and fixed to supporting wires. The lighting units are not connected to one another. Thus, clearance is likely to occur between the lighting units. In the lighting apparatus comprising two or more light-emitting units, if a clearance is present between adjacent light-emitting units, light may leak from the clearance. Therefore, the lighting apparatus comprising two or more light-emitting units is required to have a structure causing no clearance between adjacent light-emitting units.

BRIEF SUMMARY OF THE INVENTION

A luminaire according to an embodiment of the invention is securely installed in a part, such as a ceiling, and is simplify the installation operations. The luminaire comprises a light-emitting unit, a main body frame, a support frame, and a lighting unit, for example. The light-emitting unit comprises light-emitting elements. The main body frame supports the light-emitting unit, and is formed rectangular having a hook-shaped engaging piece on one side. The support frame is formed square surrounding the outer periphery of the main body frame, and has a groove-shaped receiving place to engage with the engaging piece of the main body frame, on one internal side. The lighting unit turns on the light-emitting elements.

The light-emitting unit comprises a base substrate, a reflector, and a terminal unit. The base substrate is a plate, on which two or more light-emitting elements are mounted. The reflector is attached on the side of the base substrate, on which the light-emitting elements are mounted, and has a reflection surface formed by slopes surrounding each light-emitting element. The terminal unit is mounted on the base substrate, and connected to the light-emitting elements.

The lighting unit comprises a case, and a lighting circuit. The case is fixed to the support frame, and is suspended from a ceiling with a suspension bolt. The lighting circuit is housed in the case. In this case, the case comprises a top plate, a side plate which continued from the top plate, and a support port which is opened across the top plate and side plate. The support port comprises a hitching part, and a entering part. The hitching part is provided in the top plate, and is formed to permit insertion of the suspension bolt and not to permit insertion of a nut to be attached to the suspension bolt. The entering part is provided in the side plate continuing to the hitching part, and is formed to permit insertion of the nut attached to the suspension bolt.

The lighting circuit has a power cable extending from a side in which the case and the support frame are jointed. The light-emitting unit has a lead wire extending from the terminal unit arranged on the side having the engaging piece. The power cable is connected to the lead wire. The support frame has two or more spots to assemble the case along the corresponding side.

The luminaire further comprises an engagement unit to hold the main body frame inside the support frame. The engagement unit consists of a stopper piece, and a lock mechanism. The stopper piece is provided in one of an outer peripheral edge of the main body frame opposite to a side having the engaging piece, and an inner peripheral edge of the support frame adjacent to the outer peripheral edge. The stopper piece moves relatively to the main body frame and support frame, and engages them. The lock mechanism holds the stopper piece at a position to engage the main body with the support frame.

The engagement unit may further comprise a shaft having a stopper piece, and a bearing capable to rotationally move the stopper piece about the shaft. In this case, the lock mechanism is provided between the shaft and bearing, and holds the stopper piece to a rotational position where the main body frame engages with the support frame.

When the light-emitting unit has a plurality of the base substrates, each terminal unit of the base substrates is arranged in a cavity surrounded by the reflector and base substrate. The terminal units provided on adjacent base substrates are connected through connecting lead wires arranged in the cavity.

When the light-emitting unit has a plurality of the reflectors, each reflector has a jointing piece extending perpendicularly from the outer periphery to the base substrate. The reflectors are arranged so that the jointing pieces are opposed to each other and the adjacent outer peripheries are fit. The jointing pieces of the adjacent reflectors are united with each other by a fastening means which determines the relative positions and fastens the jointing pieces. The luminaire configured as above is easy to install in an installation place on a ceiling.

In the invention, the luminaire is preferably applied to relatively large luminaire installed on a ceiling, such as luminaire for home, office and other facilities. The luminaire of the invention may be applied to small luminaire. The luminaire of the invention may also be applied to luminaire, which is recessed in an appropriate installation site on a ceiling, or directly assembled to a ceiling.

In the invention, the light-emitting element may use a semiconductor such as a light-emitting diode, an organic electroluminescence (EL), and semiconductor laser, as a light-emitting source. An incandescent lamp such as a small halogen lamp or a small cold cathode fluorescent lamp may be used as a light-emitting source, as long as it can form a flat light-emitting unit. The light-emitting element is not limited to a white light-emitting element. According to the purposes of the luminaire, red, blue or green light-emitting element may be used, or these colors may be combined.

Necessary number of light-emitting elements of the light-emitting unit are selected and arranged on a substrate. The whole figure of the unit is square or rectangular, and forms a flat surface light source. The light-emitting unit comprises sixteen light-emitting element groups, for example. The light-emitting unit may comprise one or more, four for example, light-emitting element groups. The shape of the light-emitting unit may be selected from rectangle shape which include a linear long bar, round shape which is circle or ellipse, or polygonal shape which is hexagon or octagon.

The light-emitting unit may have a reflector to reflect light from a light-emitting element, for example. The light-emitting unit may be provided with a transmissive plate made of opaque or translucent synthetic resin or reinforced glass, on the front side of the light-emitting unit to cover the light-emitting element. A lattice-shaped light control unit may be provided on the front side of the light-emitting unit.

The main body frame supports the light-emitting unit on the inner peripheral side, and forms a square equipment body together with the light-emitting unit. The main body frame is preferably made of heat-resistant weather-resistant insulating synthetic resin, such as polybutylene terephthalate (PBT). The main body frame may be made of a steel plate or metal such as stainless steel or lightweight material, such as aluminum, with high heat conductivity, considering heat radiation performance.

The equipment main body comprises a main body frame and a support frame. The equipment main body may be a housing comprising a single piece. The structure connecting the main body frame to the support frame is configured to be easily removed by engaging a engaging piece of the main body frame with a groove of the support frame. The structure connecting the main body frame to the support frame may be an ordinary hinge or a permanently-set hinge mechanism.

The base substrate is a part to mount light-emitting elements. Therefore, as the light-emitting unit is formed linear, round or polygonal, the base substrate is formed to meet the shapes of the light-emitting units. The base substrate shall be formed to meet the equipment main body, and may not correspond to the shape of the light-emitting unit.

The engaging piece is made in the form of a hook projecting on one side of the rectangular main body frame, and is preferably formed in one piece with the main body frame made of synthetic resin, for example. A separate hook-shaped metallic engaging piece may be provided to one side of the main body frame.

The lighting unit consists of a lighting circuit, which converts ac 100V into dc 24V, and supplies the converted dc voltage to a light-emitting diode, for example. The lighting unit includes a case member to install the lighting circuit. The lighting unit is allowed to be supported by the equipment main body.

Once the lighting unit is assembled to the support frame, the lighting unit is installed together with the support frame when the support frame is installed on a ceiling. This facilitates installation of the luminaire. The length of the lead wire used for wiring and connecting the lighting unit and light-emitting unit can be reduced, when the terminal unit of the lighting unit is provided close to the engaging piece of the main body frame. Since the lead wire does not disturb the installation and maintenance operations for the luminaire, the operations become easily.

The engagement unit moves the stopper by the rotational operation, and engages the main body frame with the support frame. This facilitates the operation of assembling the main body frame and support frame. The engagement unit is configured to engage the frames by two or three times of simple rotational operation or sliding operation. The lock mechanism to control the movement of the stopper may be configured to fit a projection into a recess, or to fit a projection into a hole or groove, so as to release the locking. The lock mechanism is configured not only to control movement, but also to release the locking. However, when the installation operation is given priority, the lock mechanism needs not to be releasable. The lock mechanism may not have a release function.

The base substrate comprises a substrate and a circuit board. The substrate is made of synthetic resin, or metal with high heat conductivity, such as steel, aluminum and copper. The circuit board is a part to mount light-emitting elements. The circuit board may be made of metal such as copper and aluminum, or nonmetal such as glass epoxy material, paper phenol material, and glass composite. The circuit board may also be made of ceramics when the cost is reasonable. Further, the base substrate may comprise a circuit board only. A light-emitting diode chip as a light source is mounted on a wiring pattern formed on the circuit board. A specific means is not used for forming and mounting the circuit board.

The support frame supports the main body frame on the inner periphery, and forms the square luminaire together with the light-emitting unit and main body frame. Heat-resistant weather-resistant insulating synthetic resin, such as polybutylene terephthalate (PBT), is suitable for material of the support frame, like the main body frame. The main body frame may be made of a steel plate or metal such as stainless steel or lightweight aluminum with high heat conductivity, considering radiation performance.

The receiving place is formed as a groove on each side, or four inner sides, of the square support frame. The receiving place may be formed only on one side, not on all of the four sides of the support frame. The receiving place may also be formed in one piece with the synthetic resin support frame, or a separate groove-shaped metallic member may be attached to each side of the support frame.

The reflector is optically designed to be able to obtain desired light distribution. The reflector is configured to have a reflection surface covering the area around the light-emitting element to obtain light distribution rotationally symmetric with respect to the center axis of the light-emitting element. The reflection surface is a side of so-called square pyramid, or a concave side of a conical having a rectangular opening shape. On the rear side of the reflection surface, a cavity having a triangular vertical cross-section is formed. The reflection surface may be formed as a concave of a conical having a circular shape of opening. In this case, on the rear side of a curved and inclined bowl-shaped reflection surface, a corresponding cavity is formed. The reflection surface is not limited to a specific shape.

As a material of reflector, heat-resistant weather-resistant insulating synthetic resin, such as polybutylene terephthalate (PBT), acrylic, or acrylonitrile-Butadiene-Styrene (ABS) is used considering radiation performance. A reflector is formed in one piece. The surface of the reflector may be painted white, or mirror finished, or semi-mirror finished by evaporating or plating metal such as aluminum and silver. Further, the reflector may be made of metal such as aluminum and copper, and may be painted white, evaporated, or plated.

The reflector may be provided in the number corresponding to the number of light-emitting elements, or the number of light-emitting element groups. Reflectors formed separately may be combined to obtain the same light distribution. Reflectors with different light distribution may be combined. One common reflector may be provided for one or more light-emitting elements or light-emitting element groups. The reflector is arranged so that it is layered on the base substrate. The reflector is combined with a light-emitting element and base substrate, forming a light-emitting unit as a module.

For example, when four reflectors constitute a reflection unit, the jointing pieces of adjacent reflectors are diagonally placed at the corners of each reflector. Each jointing piece is formed as a ¼-divided part of a cylinder so that four jointing pieces form one cylinder when they are combined. The shape of a jointing piece may be rectangular or polygonal, and the shape of combined jointing pieces may be a square or polygonal column. The shape of a jointing piece may not be a perfect circle in cross section when it is combined with other jointing pieces. Clearance is allowed between jointing pieces. Namely, a jointing piece may have any form as long as no clearance exists between adjacent reflectors when combined with other jointing pieces. A jointing piece may be formed in one piece with the reflector, or may be separately formed and attached to the corners of a reflector.

The terminal unit connected to the light-emitting element is configured to electrically connect the lead wires, which supply electrical power to the light-emitting elements, provided on the base substrate. The light-emitting element and terminal are connected by using a connector on a wiring pattern formed on the base substrate. The lead wires may be directly soldered or screwed to the wiring pattern. Wires may be directly connected to the light-emitting elements without using a wiring pattern.

The lead wires are used to connect the terminal unit to the light-emitting unit As a power supply, or to connect adjacent light-emitting units. The lead wires and terminal unit are connected through the above-mentioned connector. The lead wires may be directly connected to the wiring pattern on the base substrate by soldering and or screwing. The lead wires connected to the terminal unit are housed in the cavity formed between the reflector and base substrate. The lead wires may be completely or partially housed in the cavity, as long as the lead wires do not disturb the installation operation.

When the light-emitting unit having a plurality of the base substrates is used in one luminaire, the terminal unit is located in the cavity formed between the reflector and base substrate. The terminal units are connected with lead wires arranged in the cavity. Therefore, the lead wires are not exposed to the rear side of the luminaire.

A fastening means unites adjacent reflectors by bundling the jointing pieces, and determines the relative positions of the reflectors. A fastening means may use a circular jointing ring made of metal or synthetic resin. The jointing ring gathers the jointing pieces by bundling them. The jointing ring may be a C-shaped incomplete ring spring member. A fastening means may use a wire or string for bundling and uniting the jointing pieces. These fastening means may be attached assuming later removal. When the jointing pieces are bonded by adhesive means, the adhesive means is included in the fastening means. The above-mentioned fastening means may be combined. Clearance between the reflectors is allowed as long as it comes within an allowable range of light leakage, or it does not spoil the appearance of the equipment.

When the light-emitting unit having a plurality of the reflectors is used in one luminaire, the reflectors can be easily assembled without clearance by bundling the jointing pieces by the jointing ring. Therefore, the reflectors do not leak light.

As cavities formed in the reflectors are combined, a cavity formed between the reflector and base substrate at the junction of adjacent reflectors may be larger than a single cavity. A cavity may be formed only in one reflector. Adjacent reflectors are preferably joined without clearance from the viewpoint of the equipment appearance. Clearance between adjacent reflectors is allowed as long as it does not spoil the appearance of the equipment.

When the case of the lighting unit has a support port which includes a entering part and a hitching part, the luminaire can be securely installed in an installation site on a ceiling, and the installation workability is improved. The position to attach the case of the lighting unit to the support frame can be selected from two or more positions. This provides excellent workability in the luminaire.

The luminaire comprising the stopper piece and lock mechanism as the engagement unit can securely engage the equipment main body with the support frame. The equipment main body can be engaged with the support frame by a simple operation, when the stopper piece is configured to be rotationally movable. The stopper piece is not carelessly moved, and the engagement unit is not released, when the lock mechanism is provided.

In the luminaire, in which the terminal unit and lead wires are arranged in the cavity between the reflector and base substrate, the lead wires can be easily handled, and the lead wires do not disturb the installation operation. Further, by arranging the reflectors flatly along the base substrate, a larger light-emitting unit can be formed. The terminal units provided in the reflector and the lead wires connecting the terminal units are housed in the cavity formed at the junction of adjacent reflectors. As the lead wires are not exposed, the lead wires are easy to handle, and improves the workability of installing the luminaire.

DETAILED DESCRIPTION OF THE INVENTION

A luminaire10according to a first embodiment of the invention will be explained with reference toFIG. 1toFIG. 20.

A luminaire10is a recessed ceiling type made in the form of a flat square panel. As shown inFIG. 1, the luminaire10comprises an equipment main body B, a support frame16, an engagement unit14e, and a lighting unit17. The equipment main body B comprises a light-emitting unit A, and a main body frame14. The light-emitting unit A comprises light-emitting elements11forming a light-emitting unit. The main body frame14holds the light-emitting unit A on the inner periphery. The support frame16holds the main body frame14on the inner periphery, and pivotally supports one end portion of the main body frame14. The engagement unit14cengages the other end portion of the main body frame14with the support frame16. The lighting unit17lights up the light-emitting elements11.

The light-emitting element11comprises a light-emitting diode (LED), and a fluorescent substance. In this embodiment, the light-emitting element comprises a blue LED chip, and a yellow fluorescent substance excited by the LED chip, and emits white high power light. The light-emitting unit A comprises a base substrate11a, a reflector11c, and a terminal unit40, as shown inFIG. 5.

The base substrate11ais made of heat-resistance weather-resistant insulating synthetic resin, white polybutylene terephthalate (PBT) in this embodiment, and is molded as a square flat plate. The base substrate11amay comprise a glass epoxy or aluminum substrate. The light-emitting elements11are mounted on the front surface of the base substrate11a. The light-emitting elements11are arranged in square, four each in vertical and horizontal directions, total 16 pieces. Four base substrates of the same shape are combined. As shown inFIG. 4, the light-emitting unit A has sixty-four light-emitting elements11. The light-emitting elements11are connected in series by the wiring formed on the rear side of the base substrate11a.

The reflector11cis provided on the front surface of the base substrate11a, on which the light-emitting elements11are mounted. The reflector11cis made of heat-resistant insulating synthetic resin, white polybutylene terephthalate (PBT) in this embodiment. As shown inFIG. 4, the reflector11chas a square pyramid concave portion11dcorresponding to the number of light-emitting elements11. As shown inFIG. 5andFIG. 6, the concave portion11dis shaped like a conical or funnel, whose cross section parallel to the base substrate11ais rectangular.

As shown inFIG. 4, the light-emitting element11is located at the center of the opening11eat the bottom of the concave portion11d. In other words, the light-emitting element11is provided in each concave portion11dof the reflector11c. The reflector11chas an exit port11fto emit light from the light-emitting element11to the outside. The exit port11fis formed rectangular as shown inFIG. 4.

The reflector11cis molded in one piece with sixteen concave portions11dcorresponding to each light-emitting element11. As shown inFIG. 6, the reflector11cis molded so that any part of the wall forming the concave portion11dhas the same thickness. In other words, a tunnel-shaped cavity11gis inevitably formed between the rear side of the reflector11cand the base substrate11a. The cavity11gformed between the rear side of the reflector11cand the base substrate11ahas a triangular vertical cross section. The cavity11gis extended in parallel crosses between the light-emitting elements11, and in parallel to the sides of the base substrate11aand reflector11c.

The reflector11cis configured to have a reflection surface11hon the inside surface of the square conical-shaped concave portion11d, to obtain light distribution rotationally symmetric with respect to the center axis of the light-emitting element11. The reflection surface11hcovers the part surrounding the light-emitting element11, and extends to the square exit port11f. The reflection surface11hmay be mirror finished by evaporating or plating aluminum or silver.

Four square base substrates11aand reflectors11cconfigured as described above form a square light-emitting unit A, that is a light-emitting unit, as shown inFIG. 4. In other words, the square base substrate11ahaving sixteen light-emitting elements11, and the square reflector11chaving sixteen concave portions11dare arranged in vertical and horizontal directions, two in each direction, total four. The light-emitting unit A has a radiator plate11jon the rear side of the base substrate11aopposing the side provided with the reflector11d. The radiator plate11jis made of a steel plate or metal such as aluminum with high heat conductivity, a square steel plate in this embodiment, and is formed in one piece with a brim11krising from each side of the outer periphery.

The base substrate11ais positioned on the radiator plate11jby the brim11k. The reflector11cis applied to the front side of the base substrate11a. The reflector11cis fastened to the base substrate11afrom the rear side of the radiator plate11jwith a screw, so that the bottom of the reflector closely contacts the surface of the base substrate11a. The reflector11cmay be attached to the front surface of the substrate11awith heat-resistant insulating adhesive made of silicon resin or epoxy resin. The square flat light-emitting unit A, which has the light-emitting elements11as a light source, is configured as described above.

The main body frame14is made of metal with high heat conductivity, white painted aluminum in this embodiment, and is formed in one piece with a square frame body14a. The frame body14ais sized to contain the light-emitting unit A. The equipment main body B of the square luminaire is constructed by inserting the light-emitting unit A into the main body frame14. The main body frame14is formed in one piece with an outer flange14bthat is an ornamental frame projecting outward, on four outer sides the frame body14a. The outer flange14bhas a hook-shaped projecting engaging piece14don one side, as shown inFIG. 8. The engaging piece14dis extended along one side of the frame body14a, having a predetermined cross section shape, and is formed in one piece with the outer flange14bof the frame body14a. The engaging piece14dengages with a receiving place16dof the support frame16described later, and connects one end of the equipment body B pivotally turnable to the support frame16.

The main body frame14has an engagement unit14eat substantially the middle of the side opposing the side on which the engaging piece14dis formed, as shown inFIG. 1toFIG. 3. The engagement unit14ehas a function to hold the main body frame14inside the support frame16. The engagement unit14ecomprises a stopper14e1, a bearing14e2, a screw head14e3, a projection14e4, a stopper piece14e5, and a recess14e6, as shown inFIGS. 2 and 3.

As shown inFIG. 2, the stopper14e1is a round shaft made of metal or synthetic resin, a round metallic shaft in this embodiment, and formed in one piece with the screw head14e3and stopper piece14e5. The bearing14e2is made of synthetic resin, formed in one piece with the side plate14kof the main body frame14, and movably supports the stopper14e1. The bearing14e2is shaped cylindrical extending to the outer periphery of the side plate14k, as shown inFIG. 3. The screw head14e3is provided in the end portion of the stopper14e1, penetrating the outer flange14bof the frame body14a. The stopper piece14e5is projected longwise in the direction orthogonal to the center of the axis in one piece with the stopper, as shown inFIGS. 1 and 2.

The screw head14e3has a groove to rotate the stopper14e1. As long as the stopper14e1can be rotated, the shape of the groove may be linear or cross, or may be a hexagonal hole or a particular shape corresponding to a specific jig. By making the screw head in the form not applicable to a common tool, operation by a third person can be prevented.

The projection14e4and recess14e6form a lock mechanism141as shown inFIG. 3. The lock mechanism141is provided between the stopper14e1and bearing14e2. The projection14e4is provided at the middle of the stopper14e1apart from the stopper piece14e5in the direction to the center of axis, and is projected in the direction orthogonal to the center of axis. The recess14e6is provided at the middle of the bearing14e2, and engages with the projection14e4when the stopper piece14e5comes to the position where the main body frame14engages with the support frame16. As shown inFIG. 3, the recess14e6of this embodiment is formed by a small hole penetrating the cylindrical wall of the bearing14e2.

The metallic shaft of the stopper14e1is inserted into the bearing14e2through a penetrated hole14mformed in the outer flange14bof the main body frame14. When the screw head14e3is turned, the stopper piece14e5is separated from the side plate14kof the main body frame14, and engages with the inner flange16bof the support frame16. At the same time, the projection14e4of the lock mechanism141is rotated. At this time, the resin-made bearing14e2is bent by its own elasticity. In the state in which the stopper piece14e5engages with the inner flange16b, the projection14e4fits in the recess14e6of the bearing14e2. As a result, the rotation of the stopper14e1is controlled, and the stopper is locked.

The inner flange14nis formed in one piece with the main body frame14in the inner periphery of the frame body14aas shown inFIGS. 1 and 2. The inner flange14nis an ornamental frame projecting to the inside of the frame body14a. The inner flange14nlocks the light-emitting unit A, so that the light-emitting unit A does not come out the main body frame14when it is inserted into the main body frame14. The light-emitting unit A is held in the main body frame14so that when the unit A is inserted into the main body frame14, four locations of the unit A are pressed to the inner flange14nof the main body frame14by a pressing member such as a leaf spring.

The luminaire10of this embodiment comprises a transmissive plate18and a light control unit19as shown inFIG. 1. The transmissive plate18is arranged on the front side that is a projecting side of the light-emitting unit A. The transmissive plate18is formed square, and made of translucent opaque synthetic resin, so as to cover the light-emitting element11and reflector11c. The light control unit19is arranged between the transmissive plate18and inner flange14n. The light control unit19is made in the form of a square lattice to be housed in the frame body14a, and has sufficient length in the direction of the light emitted from the light-emitting element11. The transmissive plate18and light control unit19are inserted into the frame body14aof the main body frame14, together with the light-emitting unit A. In the inner flange14nof the main body frame14, the light control unit19, transmissive plate18and light-emitting unit A are layered in this order, and held by a holding member.

The support frame16is provided in an installation site on a ceiling as shown inFIG. 13. The support frame16is made of metal with high heat conductivity, such as aluminum alloy painted white like the main body frame14, in this embodiment, and is formed in one piece with the square frame body16a. The frame body16ais sized to contain the main body frame14, as shown inFIG. 1andFIG. 7. The support frame16supports the square equipment main body B comprising the light-emitting unit A and main body frame14as shown inFIG. 1.

The support frame16has an inner flange16bin the frame body16a, which is formed in one piece of the support frame and extended inward. The distal end portion of the inner flange16bis formed in one piece with a step16c, as shown inFIG. 8. In the step16c, a shallow groove-shaped receiving place16dopening upward is formed in the inner flange16bas shown inFIG. 8. The receiving place16dis formed long in one piece with the frame body16aalong at least one side of the frame body. The luminaire10of this embodiment has the receiving place16don every side, or four sides, of the square support frame16. In the luminaire10, the outer flange16eextending outward is formed in one piece with the frame body16a. The outer flange16efunctions as an ornamental frame when the equipment is installed on a ceiling.

The groove-shaped receiving place16dengages with the engaging piece14dof the main body frame14as shown inFIG. 8. As the engaging piece14dengages with the receiving place16d, the main body frame14is swiveled with respect to one side of the support frame16, just like a hatch is opened and closed. The engaging piece14dand receiving place16dfunction as a hinge C as shown inFIG. 8, and prevents coming-off of the main body frame14from the support frame16when the main body frame14is released, as shown inFIG. 9.

The support frame16and main body frame14are shaped square. The receiving place16dis formed on four sides of the support frame16. Therefore, the engaging piece14dof the main body frame14can engage with any receiving place16on any side. The support frame16has a steel-plate mount piece16gon a pair of opposing side plates16fas shown inFIG. 11. The mount piece16ghas a screw hole16hat the center as shown inFIG. 12.

The lighting unit17comprises a lighting circuit171and a case17a. The lighting circuit17aconverts ac 100V into dc 24V, and supplies it to a light-emitting diode chip. The ac voltage and converted dc voltage supplied to the lighting circuit are not limited to the above valves. The voltage values are different in countries and localities where the luminaire10is installed, or the conditions of using the luminaire10.

As shown inFIG. 11, the case17ais made of a steel plate, and is made in the form of a long rectangular parallelepiped reaching the opposing side plates16fof the support frame16. The lighting circuit171is housed in the case17a. The side plates17cformed at both ends of the case17aare continued through a top plate17d. The case17ahas a support port172cut across the side plate17cand top plate17d. The support port172comprises a entering part17eand a hitching part17f. The entering part17eis opened on the side plate17c. The hitching part17fis opened on the top plate17d, and is continued to the entering part17e.

The case17aformed as above is supported by suspension bolts20and nuts21as shown inFIG. 11andFIG. 13. The suspension bolts20are extended downward from a support member30on a ceiling. The nuts21are assembled to the suspension bolts20. The entering part17eis sized to pass the nut21attached to the suspension bolt20. The suspension bolts20can pass the hitching part17finward from outside the side plate17c, while the nuts21cannot pass the hitching part17fformed in the side plate17cor the top plate17d.

The side plate17chas a connecting hole17gin the lower part of the entering part17e. The case17aholding the lighting circuit171is located across the side plates16fprovided on the opposite sides of the support frame16, as shown inFIG. 11. The connecting hole17gis aligned with a screw hole16hof a mount piece16gattached to the side plate16fof the support frame16, and is fastened with a screw. The screw hole17hand connecting hole17gmay be provided at reverse positions. In other words, a penetrating hole may be provided in the mount piece16g, and a screw hole may be provided in the side plate17c.

Further, as shown inFIG. 11, a terminal unit17jconnected to the output part of the lighting circuit171is led out from one side of the case17a. As shown inFIG. 14, the light-emitting unit A has a connector12cat the distal end of a lead wire41connected to the input terminal. The terminal unit17jis connected to the connector12c. As shown inFIG. 14, the terminal unit17jis provided sufficiently long not to receive a tensile force in the state being connected to the connector12c, even if the main body frame14is opened to the position suspending from the support frame16. The lead wire41connected to the connector12cmay be provided sufficiently long. The case17amay be located so that the side from which the terminal unit17jis led out comes close to the receiving place16dof the support frame16connected to the engaging piece14dof the main body frame14.

As described above, the luminaire10comprising a light-emitting unit A, a main body frame14, a support frame16, and a lighting unit17is installed on a ceiling X that is an installation place in the procedures shown inFIG. 13toFIG. 15. The ceiling X has a square hole h that is previously opened to the size to allow insertion of the support frame16. Two suspension bolts20are provided in the support member30on the backside of the ceiling. These suspension bolts20are prepared at the positions corresponding to the support ports172formed in the case17aof the lighting unit17. Each suspension bolt20has two nuts21as shown inFIG. 11.

First, as shown inFIG. 11, the lighting unit17is mounted on the support frame16. Then, as shown inFIG. 13, the support frame16combined with the lighting unit17is installed in the hole h on the ceiling X with the case17afaced up. In the case17ainserted into the ceiling X, the nut21of the corresponding suspension bolt20is inserted into the entering part17eof the support port172. At this time, the lower nut21of two nuts21is inserted into the support port172through the entering part17e. The suspension bolt20is inserted into the hitching part17ffrom the outside of the side plate17cof the case17a. The upper nut21is previously screwed at a sufficiently high position to be positioned above the top plate17dof the case17a. When the other suspension bolt20is inserted into the corresponding support port172of the case17a, one of the suspension bolts20is curved, and the lower nut21is inserted through the entering part17e. The suspension bolt20is inserted into the support port172through the hitching part17f.

After the suspension bolt20is inserted into the support port172, the support frame16is adjusted to the hole h. At this time, the installation position is adjusted by sliding the support frame16to the suspension bolt20in the range of the hung-up part17fof the case17a, so that the jagged inner inside edge of the hole h is hidden by the outer flange16e, which becomes an ornamental frame of the support frame16. As a result, the installation position of the support frame16to the ceiling X is determined. After the installation position of the support frame16is determined, two nuts21of each suspension bolt20are tightened so as to hold the case17afrom the upper and lower sides. As a result, the case17ais secured to two suspension bolts20. In the above procedure, the support frame16is supported by the support member30on the backside of the ceiling through the case17aof the lighting unit17, as shown inFIG. 13.

The lighting unit17is attached across two sides of the support frame16, crossing over the frame body a. Therefore, as shown inFIG. 11, the side of the lighting unit17not connected to the support frame16forms an opening a leading to the backside of the ceiling. The operation of installing the support frame16on the ceiling X can be done while visually checking the conditions of the backside of the ceiling or the states of the suspension bolts20and nuts21, through the opening a. A series of operation of securing the support frame16to the ceiling X is performed in the state in which the equipment main body B combined with the light-emitting unit A and main body frame14is not being assembled to the support frame16. The support frame16is made of light material such as aluminum and synthetic resin, and can be easily held up when installing.

Next, the main body frame14is raised, and the engaging piece14dis engaged with the receiving place16dof the support frame16. As the receiving place16dis formed on four sides of the square support frame16, the engaging piece14dof the main body frame14can engage with any lock mount16d. Therefore, it is possible to engage appropriate engaging piece14dwith suitable receiving place16d, according to conditions such as obstacles around the ceiling X. As described above, the main body frame14is suspended from one side of the support frame16. The light control unit19, transmissive plate18, and light-emitting unit A are inserted in this order into the frame body14aof the suspended main body frame14, and held by a holding member. As a result, the light-emitting unit A is assembled in one piece with the main body frame14as shown inFIG. 14.

The terminal unit17jled out from one side of the case17aof the lighting unit17is connected to the connector12cattached to the distal end of the lead wire41of the light-emitting unit A. When the wiring of the lighting unit17and light-emitting unit A is done close to the hinge C, the lead wire41of the light-emitting unit A can be educed. The wire connecting operation can be done while the main body frame14is being suspended from the support frame16, and improving the workability.

The hinge C is constructed by engaging the engaging piece14dwith the receiving place16d. The main body frame14is rotationally moved about the hinge C, the center of axis, in the direction of pushing up the hinge C as indicated by the arrow inFIG. 14, and closes the opening of the support frame16so as to fit the main body frame14in the support frame16.

The main body frame14makes the engagement unit14eprovided on the side opposite to the hinge C contact with the flange16bof the support frame16. As shown inFIG. 2andFIG. 3, when the screw head14e3of the stopper14e1exposed to the surface of the main body frame14is turned to the left or right by using a specialized tool, the stopper piece14e5separates from the side plate14kof the main body frame14, and engages with the inner flange16b. Namely, the main body frame14is assembled to the support frame16, when one side engages with the engaging piece14dand receiving place16d, and the other side engages with the engagement unit14e.

The projection19e4of the lock mechanism141fits in the recess14e6of the bearing14e2and the rotational movement of the stopper14e1is limited as shown inFIG. 3, when the stopper piece14e5engages with the inner flange16bas shown inFIG. 2. The stopper14e5is not loosened by vibration even if the engagement unit14eis used for a long period. Therefore, the engagement unit14eis not disengaged from the inside of the inner flange16bof the support frame16. The equipment main body B is securely jointed to the support frame16, and prevented from coming off, and the safety is secured. The luminaire10comprising the light-emitting unit A, main body frame14, support frame16and lighting unit is installed on the ceiling X in the above procedures.

The edge of the opening on the ceiling X is covered by the outer flange162of the support frame16as shown inFIG. 13toFIG. 15. The outer flange16eof the support frame16and the outer flange14band inner flange14nof the main body frame19are arranged on the same level, and flatly installed on the ceiling X, providing good appearance. When the luminaire10is lit, the light-emitting elements11of the light-emitting unit A are lit white. The light emitted from the light-emitting elements spreads downward and sideways. This light is reflected on the reflection surface11hof the reflector11c, lighting a wide circular area around the luminaire, as well as the area immediately below the luminaire. Further, a part of the light reflected on the reflection surface11his emitted to the sideways of the luminaire10, lighting a wide area on the ceiling X.

The heat generated from the light-emitting elements11during lighting of the luminaire10is radiated from the base substrate11ato the outside through the steel-plate radiator11j. The heat from the lighting unit17is radiated through the steel-plate case17aand aluminum support frame16. This prevents lowering of the light-emitting efficiency of the light-emitting diodes constituting the light-emitting elements11. In other words, the luminaire10can prevent lowering of light flux accompanying with a temperature increase. The service life of the light-emitting diodes is increased, and the reliability of the circuit components of the light-emitting unit17is improved.

The light-emitting unit A is removed in the following procedures, when the light-emitting unit A is removed for maintenance of the light-emitting elements11as a light source or other parts. First, as shown inFIG. 2andFIG. 3, the screw head14e3of the stopper14e1is turned to the left or right by using a specialized tool. The resin-made bearing14e2is bent by elasticity, and the projection14e4is disengaged from the recess14e6of the bearing14e2, and the lock is released. The turning of the stopper14e1releases the engagement between the stopper piece14e5and inner flange16band the engagement between the projection14e4and recess14e6of the lock mechanism.

When the engagements are completely released, the main body frame14is rotationally moved about the center of axis of the hinge C, in the direction reverse to the arrow shown inFIG. 14from the support frame15.FIG. 8shows the cross section of the hinge C in the state in which the main body frame14closes the opening a of the support frame16.FIG. 9shows the cross section of the hinge C in the state in which the main body frame14opens the opening a of the support frame16. When the main body frame14is opened, the engaging piece14dengages with the receiving place16das shown inFIG. 9, the main body frame14is suspended in being opened without coming off the support frame16as shown inFIG. 14.

First the holding member is removed, and the light-emitting unit A is removed from the main body frame14, when the light-emitting unit A is removed from the main body frame14in the state in which the main body frame14is being suspended from the support frame16. When the light-emitting unit A is removed together with the main body frame14, the main body frame14is turned farther from the state shown inFIG. 9in the opening direction as shown inFIG. 10, and the engaging piece14dis disengaged from the receiving place16d. The light-emitting unit A can be replaced in a stable place after once removing together with the main body frame14, when only the light-emitting unit A is replaced. Therefore, the high-place operation can be reduced, when the luminaire10is installed on a high ceiling such as the ceiling in a hall, a dome, a stadium, and a theater.

Further, when the luminaire10is replaced, first the equipment main body B is removed from the ceiling X as described above, and then the support frame16and lighting unit17are removed from the ceiling X in the procedures reverse to the installation. In particular, the nuts21of the suspension bolts20are loosen, one of the suspension bolts20is curved, and slid from the hitching part17fto entering part17eof the case17a. One of the suspension bolts20is removed from the case17aby passing the nut21through the entering part17e. The case17ais slid for the other suspension bolt20, after the one of the suspension bolts20is removed. The nut21is through the entering part17e, and the other suspension bolt20is removed from the hitching part17f. The lighting unit17can be removed together with the support frame16in being attached to the support frame. The operation of removing the support frame16and lighting unit17can be performed while monitoring the states of the suspension bolts20and nuts21through the opening a of the support frame16.

As described above, according to this embodiment, the luminaire10comprises the main body frame14to house the light-emitting unit A, and the support frame16to hold the main body frame on a ceiling, which are formed as separate disassembling parts. The main body frame14has a hook-shaped engaging piece14don one side of the square frame body14ashaped. The support frame16has a groove-shaped receiving place16dto engage with the engaging piece14don each side of the square frame body16a. First, only the support frame16is installed on the ceiling X, and then the main body frame14combined with the light-emitting unit A is installed, when the luminaire10is installed. The installation operation can be performed while monitoring the situation of the backside of the ceiling and the states of the suspension bolts20and nuts21through the opening a of the support frame16. The main body frame14and support frame16can be separately installed. Hence the installation operation is light and easy.

The main body frame14is jointed to the support frame16by engaging the engaging piece14dwith the receiving place16dof the previously installed support frame16. The light-emitting unit A can be installed in the main body frame14being suspended from the support frame16. As described above, when the luminaire10is installed on a ceiling, first the support frame16made of light material such as synthetic resin or light metal such as aluminum is installed, and then equipment main body B combined with the light-emitting unit A and main body frame14is installed. In a conventional luminaire formed in one piece, a relatively light part such as a lighting unit must be supported until a luminaire is completely installed and suspended from a ceiling.

The luminaire10of this embodiment facilitates installation on an installation site such as a ceiling. In particular, the luminaire10adopting a light-emitting diode as a light source is light in weight and excellent in workability in installation.

Further, the support frame16has a receiving place16don four sides of the square frame body16a, as shown inFIG. 11andFIG. 13. Therefore the main body frame14can engage the engaging piece14dwith any receiving place16don any side. It is possible to select suitable engaging piece14dand receiving place16d, by checking whether the main body frame14can be opened and closed with respect to the support frame16, or watching situation, or obstacles near the ceiling. On the occasion of maintenance of the luminaire10after the equipment is once installed, the main body frame14is removed from the support frame16. It is possible to avoid contacting of the light-emitting unit A with an obstacle near the ceiling X by checking before installation.

The engaging piece14dand receiving place16dare shaped long along one side of the frame body14aand16aof the main body frame14and support frame16as shown inFIG. 7. As the engaging piece14dengages with the receiving place16din a wide area, the mechanism of the hinge C is stabilized, and the operability is improved in rotationally moving the main body frame14. As the engaging piece14dand receiving place16dare provided over the entire length of one side of the frame bodies14aand16a, clearance between the main body frame14and support frame16is negligible. This improves the appearance of the luminaire10.

The case17aof the lighting unit17is attached to the support frame16as shown inFIG. 11. In the luminaire10, the installation operation is simplified, since the lighting unit17can be installed simultaneously when the support frame16is installed on the ceiling X. When the terminal unit17jof the lighting unit17is provided close to the groove-shaped receiving place16dof the support frame16, that is the hinge C, it is shortened the wiring length of the lead wire41connecting the lighting unit17and light-emitting unit A. Since the lead wire41is wired in a minimum necessary length on the rear side of the light-emitting unit A, the lead wire41does not disturb the installation and maintenance of the luminaire10. This facilitates the installation and maintenance. In addition, as the length of the lead wire41is reduced, a risk of breaking the wire is decreased. As the necessary length of the lead wire is reduced, the material cost can be decreased, reducing the total costs.

In the luminaire10of this embodiment as shown inFIG. 13throughFIG. 15, the case17aassembled with the lighting circuit171is supported by the suspension bolts20. As the luminaire10is installed in an installation site on the backside of the ceiling X, the luminaire10is securely and rigidly supported compared with a conventional luminaire which is secured to a ceiling panel by the elasticity of a leaf spring. Therefore, the size of the luminaire10can be increased. In this case, the supporting structure has a support port172cut across the side plates17cat both ends of the case17aand the top plate17d. As the support port172is provided at a corner with high rigidity, the case17ais prevented from unnecessary deformation. The support port172includes a entering part17eand a hitching part17f, which are secured to suspension bolt20with nut21. The entering part17is sized to allow insertion of the nut21of the suspension bolt20. The hitching part17fis sized to permit insertion of the suspension bolt20, but not to permit insertion of the nut21. The nut21secured to the suspension bolt20is inserted into the hitching part17fthrough the entering part17e. The suspension bolt and case17acan be engaged and supported by simple sliding operation, improving the workability.

The case17ais supported across the support frame16. An opening a is formed on both sides of the lighting unit17. The states of the suspension bolt20and nut21can be checked and adjusted through the opening a by inserting a hand.

Further, the luminaire10is provided with the engagement unit14ein the main body frame14opposite to the hinge C as shown inFIG. 14andFIG. 15. The engagement unit14eengages with the inner flange16bof the support frame16by rotating the stopper piece14e5. The stopper14e1can be operated simply by turning the screw head14e3exposed to the surface of the main body frame14by about 90°. This eliminates tedious conventional work of turning small screws many times. Even if the luminaire10is installed in a high place or dark place, the workability of specialized tool is not extremely decreased.

The engagement unit14ehas a lock mechanism141which shown inFIG. 3. The lock mechanism141securely controls the rotation of the stopper piece14e5. As the lock mechanism141is provided, the stopper piece14e5is not loosened by vibration or long-time use, and the engagement with the support frame16is not released. The main body frame14holding the light-emitting unit A is fixed to the support frame16by the engagement unit14e. The light-emitting unit A uses a small light-emitting diode as a light source, and the weight of the whole unit is decreased.

The engagement unit14eshown inFIG. 2andFIG. 3is provided in one piece with the main body frame14, and comprises a bearing14e2, and a metallic stopper14e1fit to the bearing14e2. The engagement unit14eis very simple in structure, and low in cost. The lock mechanism141has a simple structure comprising a projection14e4formed in the metallic stopper14e1, and a recess14e6formed in the bearing14e2. The locking operation can be done simultaneously with the rotational movement of the stopper14e1. Any special operation is unnecessary for locking, and the operability is maintained. The bearing14e2is formed in one piece with the main body frame14made of light material such as synthetic resin and aluminum. The bearing14e2is configured to engage the projection14e4in the recess14e6by the elastic force. The lock mechanism141needs not to use any specific elastic member such as a spring, and is very simple in structure, and low in cost. The lock mechanism is unlocked simultaneously with disengagement of the engagement unit14e, when the equipment main body B is removed from the support frame16. The luminaire10needs any releasing operation for unlocking the lock mechanism141, and the operability is excellent.

In the luminaire10of this embodiment, the receiving place16dof the support frame16is provided on all of four sides of the frame body16aas shown inFIG. 11andFIG. 13. The receiving place16dmay be provided to lock the engaging piece14dof the main body frame14, and to make the main body frame14rotationally movable with respect to the support frame16. Therefore, the receiving place may be provided only on the side opposing the side provided with the engagement unit14e. In this embodiment, the receiving place16dand engaging piece14dare formed over the entire length of the sides of the frame body14aand16a. One or both of the engaging piece14dand receiving place16dmay be shorter than the side of the frame body, as long as the function of suspending the main body frame14combined with the light-emitting unit A is ensured.

The plurality of the screw hole16hof the mount piece16gattached to the side plate16flocated on the opposing side of the support frame16are provided, three screw holes16hare provided in this embodiment, as shown inFIG. 16, for assembling the case17aof the lighting unit17to the support frame16. The screw holes16hare arranged at regular intervals, and the screw holes16hon the opposing sides are used in pair. One of the three pairs of screw holes16hmay be selected, and the position to secure the case17ato the support frame16may be selected.

For example, the screw hole16his chosen to assemble the lighting unit17at the position indicated by a broken line inFIG. 15to avoid any structure such as a C-shaped channel, which is extending on the backside of ceiling and interferes with the lighting unit17. A long hole may be provided instead of the screw hole16h, to permit selection of a desired position in the long continuously hole. In this case, a screw hole is formed in a connecting hole17gprovided on the side plate17cof the case17a.

Further, as shown inFIG. 17, the luminaire10may be installed on the inclined ceiling X. In this case, the side plate17cof the case17ais assembled rotationally movable with respect to the mount piece16gof the support frame16. As shown inFIG. 17, the case17aof the lighting unit17is suspended flatly in the direction along the level line such as the inclined surface, with respect to the suspension bolt20extended from the support member X1provided on the inclined ceiling X. The support frame16is assembled obliquely to meet the inclination of the ceiling X with the connecting hole17gtaken as a center.

In this case, the hinge C supporting the main body frame14rotationally movable with respect to the support frame16is provided on the higher side or lower side of the inclination of the ceiling X as shown inFIG. 17. If the hinge C is located with its axis of center along the direction going down the inclined surface, the main body frame14is partly opened, and the installation operation becomes difficult. In this embodiment, the receiving place16dof the support frame16is provided on all of four sides of the frame body16a. Therefore, even if the ceiling X is inclined, the receiving place16dcan be easily selected so that the hinge C is located on the higher side or lower side of the inclination.

The engagement unit14eis not limited to the rotationally movable mechanism shown inFIG. 2andFIG. 3. The engagement unit14emay engage the main body frame14with the support frame16installed on the ceiling X, and may comprise a stopper piece14e5and a lock mechanism141. In this case, the stopper piece14e5moves relatively to the main body frame14and support frame16, and engages them. The lock mechanism141holds the stopper piece14e5at the position to engage the main body frame14with the support frame16.

The stopper piece14e5may slide, and engage the main body frame14with the support frame16as shown inFIG. 18.FIG. 18shows a first modification of the engagement unit14e. The stopper piece14e5of the stopper14e1consists of a slidable piece made of metal or synthetic resin. The stopper piece14e5is slidably inserted into the guide hole14e7formed in the side plate14kof the main body frame14. The stopper piece14e5is moved by a knob14e3′ exposed to the surface of the main body frame14.FIG. 18shows the state in which the stopper piece14e5is being engaged with the inner flange16b. In this case, the lock mechanism141is constructed by engaging the projection14e4of the stopper piece14e5in the recess1426formed inside the guide hole14e7.

Further, the engagement unit14emay be provided in the support frame16as shown inFIG. 19.FIG. 19shows a second modification of the engagement unit14e. The bearing14e2is formed in one piece with the side plate16fof the support frame16. The stopper piece14e2is extended perpendicularly from the stopper14e1fit to the bearing14e2, and engages with the projection14e9formed in one piece in the direction of extending outward from the side plate14kof the main body frame14, just like supporting from the lower side. The lock mechanism141has the same structure as that shown inFIG. 2andFIG. 3.

The lock mechanism141may have a projection14e4and a recess14e6as shown inFIG. 20.FIG. 20shows a first modification of the lock mechanism141. The projection14e4consists of both ends of a pin penetrating the distal end of the stopper14e1inserted into the bearing14e2in the diametrical direction. The recess14e6consists of a pair of grooves formed at the end portion14e10of opening of the bearing14e2. When the projection14e4fits in the recess14e6, the stopper piece14e5engages the main body frame14with the support frame16.

In the lock mechanism141of this embodiment, the projection14e4is formed in the metallic stopper14e1, and the recess14e6is formed in the bearing14e2by opening a small hole. The small hole or groove-shaped recess14e6may be formed in the metallic stopper14e1or a slidable piece14e5′, and the projection14e4may be formed inside the bearing14e2or guide hole14e7. The lock mechanism141is configured to engage/disengage the projection14e4with/from the recess14e6by the elasticity of the member itself.

When the bearing14e2and stopper14e1are made of metal, the projection14e4formed in the stopper14e1consists of a metallic ball. The ball is always energized in a projecting direction by a coil spring, and is configured to engage/disengage with/from the recess14e6of the bearing14e2. The lock mechanism141secures engagement/disengagement, and clicks when engaging. Therefore, a slidable and highly operable engagement unit can be constructed.

In the above description, the equipment main body B is square, and comprises the light-emitting unit A and main body frame14, and the support frame16supporting the equipment main body. The front side shape of the luminaire10may be circular as shown inFIG. 21. In this case, the hinge C is provided in one end portion of the diameter of a circular light-emitting unit A, and the engagement unit14eis provided in the other end portion.

A luminaire10according to a second embodiment of the invention will be explained with reference toFIG. 22toFIG. 36. The components having the same functions as those of the first embodiment are denoted by the same reference numbers in the drawings, and an explanation thereof is omitted.

As shown inFIG. 22, the luminaire10is a recessed ceiling type, and adopts a light-emitting unit A made in the form of a rectangular flat plate. In this embodiment, the light-emitting unit A is shaped square. The light-emitting unit A comprises a base substrate11a, a reflector11c, a connector40, and a lead wire41. On the base substrate11a, light-emitting elements11mounted in square. The reflector11cis attached on the side of the base substrate11aprovided with the light-emitting elements11, and has a reflection surface11hsurrounding each light-emitting element11. The connector40is mounted on the base substrate11a. The connector40is a terminal connected to the light-emitting element11. The lead wire41is connected to the connector40.

As shown inFIG. 23andFIG. 25, the base substrate11acomprises four square circuit boards11a1, a radiator plate11j, and an electrical insulating plate11a2. Each circuit board11a1is composed of a member to mount the light-emitting element11including a light-emitting diode chip, for example, glass epoxy or aluminum substrate. Each circuit board11a1is a square plate. As shown inFIG. 22, the light-emitting element11is arranged in a 4-row by 4-column matrix, 16 in total, on the front surface of the circuit board11a1. A copper foil wiring pattern is formed on the rear surface of the circuit board11a1, corresponding to the arrangement of the light-emitting element11. In the light-emitting unit A shown inFIG. 22, tour pieces of the above circuit board11a1are combined.

The radiator plate11jis made of metal with high heat conductivity, such as a steel plate and aluminum. In this embodiment, the radiator plate11jis made of a steel plate. The radiator plate11jis formed in size equivalent to two or more circuit boards11a1arranged along the same plane. In this embodiment, the radiator plate11jis formed in square of the size equivalent to four circuit boards11a1arranged in square. The radiator11jhas a brim11kformed by raising the parts opposing to the sides of the circuit board11a1in one piece.

The electrical insulating plate11a2is inserted between the circuit board11a1and radiator plate11j. The electrical insulating plate11a2is a film-like insulating sheet made of heat-resistant insulating silicon resin or epoxy resin. The electrical insulating plate11a2is shaped square to be fit inside the brim11kof the radiator plate11j.

The reflector11cis arranged on the front surface of four circuit boards11a1provided with the light-emitting elements11. Four reflectors11chave the same optical design to have desired light distribution. The reflector11cis made of heat-resistant weather-resistant insulating synthetic resin in the form of a square part having the same dimensions as the circuit board11a1. In this embodiment, the reflector11cis made of white polybutylene terephthalate (PBT).

The reflector11chas a square pyramid concave portion11dcorresponding to the number of light-emitting elements11, and is formed like a so-called waffle. In other words, conical-shaped or funnel-shaped concave portions11dare arranged corresponding to the light-emitting elements11, as shown in the cross section ofFIG. 23. The bottom of each concave portion lid has an opening11e. The light-emitting element11is arranged at the center of the opening11e. The reflectors11care combined so that the bottom of the concave portion lid closely contacts the surface of the circuit board11a1.

A part corresponding to the upper contour of the concave portion11dforms a square exit port11fto emit the light from the light-emitting element11to the outside. The reflector11ccomprises sixteen concave portions11dmade of polybutylene terephthalate (PBT) and formed in one piece correspond to each light-emitting element11of one circuit board11a1. Each concave portion11dis formed surrounding the light-emitting element11. The inside surface of the concave portion11dforms a reflection surface11has shown inFIG. 23. To obtain light distribution rotationally symmetric with respect to the center axis of the light-emitting element11, each concave portion11dof the reflector11cis made in the form of a conical having a square cross section along the plane parallel to the circuit board11a1. The reflection surface11hcovers the area surrounding the light-emitting element11, and extends to the square exit port11f. The reflection surface11hmay be mirror finished by evaporating or plating aluminum or silver.

The wall forming the reflection surface11his made to have substantially the same thickness in any portion as shown inFIG. 23. Therefore, when viewed from the rear side, the reflector11cis seemed to have an array of pyramid-shaped projections. The reflector11cand circuit board11a1are layered, forming a cavity11ghaving a isosceles triangle vertical cross section between the continuous pyramids. The cavity11gis made in the form of lattice parallel to the outer peripheral sides of the reflector11cand base substrate11a.

As shown inFIG. 22, a larger square light-emitting unit A is formed by combining four pieces of light-emitting unit A, which comprises a circuit board11a1having sixteen light-emitting elements11, and a reflector11chaving sixteen corresponding reflection surfaces11h. In this embodiment, as shown inFIG. 22, the circuit board11a1and reflector lie are arranged in 2-row and 2-column, four pieces in total, on the radiator plate11j.

Four pieces of electrical insulating plate11a2and circuit board11a1are positioned by the brim11kand mounted on the radiator plate11j. Four reflectors11c1are arranged on the exit side of the circuit board11a1, and fixed to the circuit board11a1with a screw from the rear side of the radiator plate11j. The circuit board11a1and reflector11cmay be bonded by heat-resistant insulating adhesive, such as silicon resin and epoxy resin.

Sixteen light-emitting elements11are connected in series according to a wiring pattern one the rear side of the circuit board11a1. Four circuit boards11a1are connected in series by the lead wire41as shown inFIG. 22. As a result, sixteen light-emitting elements11mounted on each circuit board11a1, sixty-four in total, are connected in series within the light-emitting unit A. After all light-emitting elements11are connected in series, the light-emitting unit A is preferably wired and connected to the lighting unit17and other adjacent light-emitting units A. One circuit board11a1has an input terminal at both ends of the wiring pattern connecting sixteen light-emitting elements11in series.

The connector40is an example of terminal unit, and is connected to the input terminal of the wiring pattern. The connector40is a small connector40in this embodiment. The connector40is removably fixed to the front side of the circuit board11a1. The connector40is placed in the cavity11gto be placed between adjacent light-emitting elements11as shown inFIG. 22andFIG. 23. At this time, when the connection terminal40aof the connector40is placed facing to the outside of the circuit board11a1, the wiring operation is easy.

The lead wire41connecting the connectors40of each circuit board11a1in series is wired as follows. First, as shown inFIG. 22andFIG. 23, four circuit boards11a1are positioned so that the connectors40are faced to each other, and placed on the radiator plate11j. The connection terminal40aof each connector40mounted on each circuit board11a1is placed to face the junction P of adjacent circuit boards11a1as shown inFIG. 23andFIG. 25. The lead wire41is inserted into the connection terminal40ain this state. The connection terminals40aof the connectors40are aligned in the same direction, and can be collectively connected. The lead wire connected to each connector40is routed along the junction P of the circuit boards11a1as shown inFIG. 22andFIG. 25. The connection terminals40aof the connectors40are faced outward in the same direction. The lead wire41can be connected to the connector40at a position not interfering with each light-emitting element11, and routed at a position not interfering with each light-emitting element11.

Four reflectors11care layered on each circuit board11a1so that they are mounted along one plane. As a result, as shown inFIG. 23, the cavity11gin the outermost periphery of each reflector11cis combined at the junction Q of adjacent reflectors11c. The combined cavity11gforms a tunnel11G having an isosceles triangular cross section as shown inFIG. 23, and extends along one side of the reflector11cand circuit board11a1. Each connector40connected to the lead wire41is covered by each cavity11g. The lead wire41routed along the junction P of circuit boards11a1is housed in the tunnel11G, except for the end portions41aand41bled out from the light-emitting unit A. In other words, the lead wire41is wired without being exposed on the surface of the circuit board11a1. Therefore, the lead wire41does not disturb the assembling operation, and the workability is improved.

As shown inFIG. 22, the end portion41aled out in one direction from the tunnel11G is led to the tunnel11G of the adjacent light-emitting unit A, and connected to the corresponding connector. The connected lead wire41is passed through a tunnel formed in the adjacent light-emitting unit A. The end portion41bof the lead wire41led out in the other direction is inserted into the connector12c, and connected to the output terminal unit17jof the lighting unit17, as shown inFIG. 33. The connector12cis connected to the terminal unit17j, and the lighting unit17supplies power to all the light-emitting elements11of the light-emitting unit A.

The luminaire10of the second embodiment comprises an equipment main body B, a support frame16, an engagement unit14c, and a lighting unit17, as shown inFIG. 24. The equipment main body B comprises the above-described light-emitting unit A, and main body frame14. The main body frame14holds the light-emitting unit A on the inner periphery. The support frame16places the main body frame14on the inner periphery, and supports one end portion of the main body frame14rotationally movable. The engagement unit14cengages the other end portion of the main body frame14with the support frame16. The lighting unit17lights up the light-emitting elements11.

The main body frame14is made of metal with high heat conductivity, white painted aluminum in the second embodiment, and is formed in one piece with a square frame body14a. The frame body14ais sized to house the light-emitting unit A inside as shown inFIG. 24andFIG. 27. The light-emitting unit A is fit in the main body frame14, and the equipment main body B of the square luminaire is assembled. The main body frame14is formed in one piece with an outer flange14bthat becomes an ornamental frame projecting outward, on four outer sides of the frame body14a. The outer flange14bhas a hook-shaped engaging piece14dprojecting on one side as shown inFIG. 28andFIG. 29. The engaging piece14dis extended along one side of the frame body14a, having a predetermined cross section shape, and is formed in one piece with the outer flange14bof the frame body14a.

The luminaire10of the second embodiment comprises a transmissive plate18and a light control unit19, as in the luminaire10of the first embodiment, as shown inFIG. 24. The transmissive plate18and light control-unit19are inserted in the frame body14aof the main body frame14, together with the square light-emitting unit A. The light control unit, transmissive plate18, and light-emitting unit A are Layered and inserted into the main body frame14in this order, and are supported by the inner flange14nof the main body frame14.

The light-emitting unit A, transmissive plate18, and control unit19are held in the frame body14aby the support member30that is a holding member, as shown inFIG. 24,FIG. 26andFIG. 33. The support member30is a wire made by bending an elastic steel wire30ato meet the purpose of this embodiment. The distal end of the support member30is fixed to a predetermined position by a positioning means comprising three small holes32a,32band32cformed on the rear side of the radiator plate11jshown inFIG. 23andFIG. 27.

The proximal end of the support member30is fixed to the side plate14kof the main body frame14as shown inFIG. 24,FIG. 26andFIG. 28. The proximal end30bis slidable along the side plate14kas shown inFIG. 27. The proximal end30bis configured to rotationally move the wire30aabout the axis line inclined slightly to the vertical line of the radiator plate11jof the base substrate11a. In other words, the center of rotational movement of the wire30ais set obliquely to the vertical line of the radiator plate11j.

When the wire30ais rotationally moved, the distal end of the wire30aextending radially from the center of rotation is moved along the inclined circular orbit. As a result, by sliding the proximal end30bof the support member30and rotationally moving the wire30a, the distal end of the wire30bis moved outward from the center of the radiator plate11j, and displaced in the direction of pushing the radiator plate11jdown to the circuit board11a1. The three small holes32a,32ban32cshown inFIG. 27are prepared for cases where the distal end of the wire30ais set high, middle, and low positions for the inner flange14nof the main body frame14.

The luminaire10is provided with a mechanism which changes the position of the distal end of the support member30in the thickness direction of the main body frame14, that is, in the light emission direction. This permits use of the reflector11c, transmissive plate18and light control unit19with different dimensions in the light emission direction. As shown inFIG. 27, three small holes32a,32band32cmay be formed by penetrating the base substrate11aup to the cavity11gof the above-mentioned reflector11c. In this case, the circuit board11a1is sufficiently insulated. The number of holes, which prevents interference of the distal end of the wire30awith the light-emitting element11, is not limited to three. The number of holes depends on the number of positions to support the radiator plate11jby the support member30.

The main body frame14has an engagement unit14eto engage the main body frame14with the support frame16, on the side plate14kof the frame body14athat is the side opposite to the side forming the engaging piece14das shown inFIG. 24. The engagement unit14ecomprises a stopper14e1and a bearing14e2as in the engagement unit14eof the first embodiment. The stopper14e1is a part formed by combining a screw heat14e3, a projection14e4, and a stopper piece14e5in one piece with a shaft member. The bearing14e2is formed in one piece with the side plate14kof the frame body14a. The bearing14e2has a recess14e6inside. The projection14e4and recess14e6form a lock mechanism141. When the projection14e4of the stopper14e1engages with the recess14e6, the stopper piece14e5engages with the inner flange16b, and holds the main body frame14in the support frame16.

The luminaire10configured as above is installed on a ceiling as shown inFIG. 29toFIG. 34in the same procedures as the first embodiment. In the luminaire10of this embodiment, the receiving place16dis provided on all inner peripheral sides of the support frame16as shown inFIG. 32. The receiving place16duses the part provided on the side of the frame body16a, from which the output terminal unit17jof the lighting unit17is pulled out to the support frame16, as shown inFIG. 33. The main body frame14engages the engaging piece14dwith the receiving place16das shown inFIG. 33. In other words, the output terminal unit17jpulled out from one end of the lighting unit17is placed on the side, on which the hinge C of the support frame16and main body frame14are provided.

The luminaire of this embodiment comprises a support member30. As shown inFIG. 33, a light control unit19, a transmissive plate18, and a light-emitting unit A are inserted in this order into the frame body14aof the main body frame14suspended as shown inFIG. 33, and the light control unit19is locked on the inner surface of the inner flange14nof the main body frame14. Next, the wire30aof the support member30is rotationally moved to insert the distal end into one of the positioning small holes32a,32band32c. As shown inFIG. 33, the light-emitting unit A is pressed to the inner surface of the inner flange14nof the main body frame14by the elasticity of the wire30a, and held on the inner periphery of the main body frame14. As shown inFIG. 34, after the main body frame14is fit in the support frame16, the support member30is located at a position not interfering with the lighting unit17.

The connector12cprovided in the end portion31bof the lead wire41led out from the light-emitting unit A is connected to the terminal unit17jof the lighting unit17. As the lighting unit17and light-emitting unit A can be wired and connected in the hinge C, the lead wire41of the lighting unit may be short and does not disturb the installation operation. Further, operation of assembling the light control unit19, transmissive plate18and light-emitting unit A to the main body frame14, and the operation of wiring and connecting the terminal unit17jto the connector12ccan be performed in the state in which the main body frame14is pulled out and suspended from the support frame16. This makes the operation visible, and improves the workability.

When the light-emitting unit A as a light source is removed for replacement or maintenance, the procedures reverse to installation of the luminaire are used as same as the first embodiment. In this case, the support member30has been combined with the luminaire10of the second embodiment. Therefore, first the wire30aof the support member30holding the light-emitting unit A as shown inFIG. 33in the main body frame14is led out from the small hole32in the state in which the main body frame14has been locked to suspended from the support frame16as shown inFIG. 30. Then, the wire30ais removed from the top surface of the light-emitting unit A by turning it to remove from the frame body14aof the main body frame14.

When the light-emitting unit A is removed together with the main body frame14, first the connector12cis separated from the terminal unit17j, and as shown inFIG. 31, the engagement of the engaging piece14dwith the groove of the receiving place16dis released. As the support member30is provided, the light-emitting unit A, transmissive plate18and light control unit19are prevented from coming off the main body frame14even in the state in which the main body frame14is suspended from the support frame16.

In the luminaire10of this embodiment, a cavity11gis formed between the circuit board11a1provided with the light-emitting element11and the reflector11ccovering the area around the light-emitting element11. By arranging two or more reflectors11c, a tunnel11G of the size of combined cavities11gis formed at the junction Q of adjacent reflectors11c.

The connector40is located between adjacent light-emitting elements11in the tunnel11G. Therefore, the connector40does not contact the light-emitting elements11and energized parts. The lead wire41connected to the connector40is housed in the tunnel11G. The lead wire41does not interfere with the light-emitting elements11and energized parts. As the connector40and lead wire41do not interfere with the light-emitting elements and energized parts on the circuit board11a1, the reflector11can tightly contact the circuit board11a1. As the light emitted from the light-emitting element11does not leak to the rear side of the reflector11c, lighting loss of the luminaire10is eliminated.

Further, the lead wire41is led from one side of the frame body14aopposing the light-emitting unit A, and does not interfere with the reflector11cand light-emitting elements11. Space for housing the lead wire41is unnecessary, and the light-emitting unit A can be made compact. The connector40is adjoined to the junction P of circuit boards11a1, and arranged opposing to the connection terminal40a. This increases the efficiency of wiring the lead wire41. The lead wire41connecting adjacent circuit boards11a1is housed in the tunnel11G that is normally a dead space. As a result, the lead wire41is neatly wired for the light-emitting unit A, and the workability of installation and maintenance is improved.

In the luminaire10of this embodiment, cavities11gare combined at the junction Q of reflectors11c, forming a tunnel11G having an isosceles triangular cross section. As shown inFIG. 35, the shape of the reflector11cused in being combined may not be the same. The cavity11gis formed only in one reflector11c, and the connector40and lead wire41are located or housed in this cavity11g. In this case, adjacent reflectors11chave a side wall closed along the junction Q. When one reflector11cis provided in one luminaire10, a cavity11gis formed one side of the outermost periphery as shown inFIG. 36. The connector40and lead wire41may be located or housed in the cavity11g.

Next, a luminaire according to a third embodiment of the invention will be explained with reference toFIG. 37toFIG. 47. The components having the same functions as those of the first and second embodiments are denoted by the same reference numbers in the drawings, and an explanation thereof is omitted. Diagrams of the same structures are also omitted. Therefore, for the configuration not described in detailed in this embodiment, related drawings and explanation of the first and second embodiments will be referred to. Even components peculiar to the luminaire10of the third embodiment may be added to or replaced by the components of the luminaire10of the first and second embodiments.

As shown inFIG. 37, the luminaire10is a recessed ceiling type, and adopts a light-emitting unit A made in the form of a rectangular flat plate. In this embodiment, the light-emitting unit A is shaped square. The light-emitting unit A comprises a substrate11aon which two or more light-emitting elements11are mounted, and a reflector R which reflects the light emitted from each light-emitting element11. The base substrate11acomprises a substrate11a1, an electrical insulating plate11a2, and a radiator plate11j. In this embodiment, one base substrate11aincludes four circuit boards11a1as shown inFIG. 37toFIG. 38.

The radiator plate11jis made of metal with high heat conductivity, such as a steel plate and aluminum. In this embodiment, the radiator plate11jis made of a steel plate. The radiator plate11jis formed in square of the size equivalent to four circuit boards11a1arranged in square. The radiator11jhas a brim11kraised in one piece toward the circuit board11a1as shown inFIG. 37andFIG. 40.

One electrical insulating plate11a2is inserted between four circuit boards11a1and a radiator plate11j. The electrical insulating plate11a2is a film-like insulating sheet made of heat-resistant insulating silicon resin or epoxy resin. The electrical insulating plate11a2is shaped square to be fit inside the brim11kof the radiator plate11j.

A reflection unit R comprises four reflectors11cas shown inFIG. 37. The reflector11cis provided corresponding to the circuit board11a1. Four reflectors11care optically designed to obtain desired light distribution. Therefore, four reflectors may have the same shape, or different shapes to obtain uneven light distribution. The reflector11cis made of heat-resistant weather-resistant insulating synthetic resin. In this embodiment, one reflector11cis made of white polybutylene terephthalate (PBT) in the form of square with the same outer dimensions as one circuit board11a1. The reflector11chas a square pyramid concave portion11dcorresponding to the number of light-emitting elements11of the circuit board11a1, and is shaped like a so-called waffle. In other words, a conical-shaped or funnel-shaped concave portion11dis arranged corresponding to the arrangement of light-emitting elements11, as shownFIG. 38. The bottom of each concave portion11dhas an opening11e. The light-emitting element11is arranged at the center of the opening11e. The concave portion11dis formed surrounding the light-emitting element11.

Each reflector11chas a jointing piece11g3extending perpendicularly from the outer periphery to the base substrate11a. In this embodiment, as shown inFIG. 38, the reflector11cis formed in one body with a jointing piece11g3, which is located at least one corner Ugh, and extended to the base substrate11a. Further, as shown inFIG. 38andFIG. 39, the jointing piece11g3is not projected to the outside from the outer peripheral surface11g2of the reflector11c. In other words, the jointing piece11g3is formed as a ¼-divided part of a cylinder, as shown inFIG. 41andFIG. 42.

Four reflectors11care arranged flatly in 2-row and 2-column square along the base substrate11a. The corners11g1provided with a jointing piece11g3are butted against at the center of the base substrate11a. The jointing pieces11g3of the reflectors11care joined in the outer peripheral side11g2, and bound to form one cylinder. The bound jointing pieces11g3are united in one piece by a fastening ring11g4that is a fastening means, as shown inFIG. 39andFIG. 40. The fastening ring11g4is made of synthetic resin composed of polybutylene terephthalate (PBT) in the form of a ring. The other configurations are the same as those in the luminaire10of the first and second embodiments.

In the luminaire10, the light-emitting unit A is assembled in the following procedure. First, the electrical insulating plate11a2is attached inside the brim11kof the radiator plate11j. Next, four circuit boards11a1are positioned for the radiator plate11jwith reference to the brim11k. At this time, the circuit boards11a1are closely arranged without a clearance at the junction P. Four reflectors11care arranged corresponding to the circuit boards11a1. At this time, the corners11g1are opposed so that the jointing pieces11g3of adjacent reflectors11care made contact each other. As a result, the jointing pieces11g3of four ¼-divided parts of a cylinder are joined forming one cylinder as shown inFIG. 39andFIG. 41. A fastening ring11g4is fit onto the bound jointing pieces11g3of the reflector11cseparated from the base substrate11afrom the rear side as shown inFIG. 42.

Four reflectors11care tightly connected at the central part of the base substrate11aby the fastening ring11g4. As a result, four reflectors11ctightly contact to one another at the junction Q, and assembled as one reflector unit R. The reflector unit R assembled as one piece is positioned on the top surface of four circuit boards11a1by the brim11kof the radiator plate11j. The reflector unit R is assembled together with the circuit boards11a1by a screw inserted from the rear side of the radiator plate11j. The reflector unit may be bonded by a heat-resistant insulating adhesive such as silicon resin and epoxy resin.

As the jointing pieces11g3are connected by the fastening ring11g4at the central part of the light-emitting unit A, four reflectors11cof the light-emitting unit A assembled as above tightly contact at the junction Q. Therefore, the light emitted from the light-emitting element11does not leak from the junction Q.

The light-emitting unit A configured as described above is inserted into the main body frame14as in the first and second embodiments. The main body frame14assembled with the light-emitting unit A is combined with the support frame16, forming the luminaire10. In the luminaire10, the main body frame14may be removed from the support frame16for cleaning and maintenance or replacement of light-emitting elements. The light-emitting unit A may be removed from the main body frame14.

The reflector11cof the light-emitting unit A removed from the main body frame14can be removed from the circuit board11a1in the following procedures. First, the screw assembling the reflector11c, circuit board11a1and radiator plate11jis removed. The reflector11ccomes off the base substrate11aas one piece. Then, the fastening ring11g4binding the jointing pieces11g3is removed. The reflector11cis disassembled to four pieces.

According to the luminaire10of the third embodiment, the reflector11cis formed in one piece with a jointing piece11g3extending from one corner11g1to the base substrate11a. The jointing piece11ge3is formed as a ¼-divided part of a cylinder. When four reflectors11c1are flatly arranged along the square base substrate11a, they are placed so that the jointing pieces11g3oppose each other. The jointing piece11g3does not project outward from the outer peripheral side11g2, so that the outer peripheral side11g2that is the periphery extending from the corner11g1provided with the jointing piece11g3tightly contact each other. As a result, the reflectors11care arranged along the base substrate11a, and the reflector unit R is formed.

Adjacent reflectors11carranged so that the jointing pieces11g3contacts at the corner11g1. Adjacent four jointing pieces11g3form one cylinder. Four reflectors11cof the light-emitting unit A are tightly connected by the fastening ring11g4at the central part of the light-emitting unit A. As four reflectors11ctightly contact without clearance at the junction Q, the light emitted from the light-emitting element11does not lead from the junction Q. Further, as no clearance is found at the junction Q when viewed from the front side of the reflector11cwhile the luminaire is not lit, the light-emitting unit A and luminaire10provide excellent appearance. The jointing piece11g3is provided extending perpendicularly to the base substrate11ain the state not projecting outward from the outer peripheral side11g2of the corner11g1of the reflector11c. There is no projection at the junction Q of adjacent reflectors11c, and the outer peripheral sides11g2of adjacent reflectors11ctightly contact without clearance.

The reflector11cmay be provided with a jointing piece11g3at least one corner11g1. This simplifies the structure of the reflector. When four reflectors11care assembled, the reflectors11care positioned so that the jointing pieces11g3of adjacent reflectors11ccontact each other. Four reflectors may be made in the same shape. The number of parts is decreased, and the cost is reduced.

In the third embodiment, the junction Q of the outer peripheral side11g2located on the outer periphery of the light-emitting unit A, connecting the corners11g1of the reflectors11cat the central part of the light-emitting unit A, is positioned by the brim11kformed on four sides of the radiator plate11jso that no clearance is generated. A junction may be provided on the outer peripheral side of the light-emitting unit A as shown inFIG. 43, without depending on the brim11k. A junction comprises ¼-divided parts of a cylinder, and a semicircular fastening ring11g4. The jointing piece11g3is provided at the corner11g1positioned on the outer peripheral side of the light-emitting unit A. The fastening ring11g4is fit onto two jointing pieces11g3contacting each other.

By using the D-shaped semicircular fastening ring, two reflectors11ccan be combined into a light-emitting unit A. As shown inFIG. 43, the jointing piece11g3that is a ¼-divided part of a cylinder is formed at opposing corners of adjacent reflectors11c, and the D-shaped fastening ring is fit onto the jointing pieces to fasten them. As shown inFIG. 44, fan-shaped three reflectors11cmay be combined into a circular light-emitting unit A. In this case, a jointing piece11g3is provided at a corner11g1of a reflector11cpositioned at the center of the light-emitting unit A. The jointing piece11g3is formed as a ⅓-divided part of a cylinder. These parts are joined by a circular fastening ring11g4. A jointing piece11g3joined by a fastening ring11g4may be provided to tightly contact the junction Q located in the outer periphery of the light-emitting unit A. The jointing piece11g3is formed as a ½-divided part of a cylinder at corners11g1of adjacent reflectors.

In the third embodiment, four jointing pieces11g3are combined into a cylindrical column. As shown inFIG. 45, each jointing piece11g3may be formed as a part of a square column, and fastened by a circular or square fastening ring. Further, as shown inFIG. 46, four jointing pieces11g3may be combined into a form whose surface is tapered and reduced in diameter toward the base substrate11a. The fastening ring11g4is formed to have a tapered hole. The jointing pieces11g3and fastening ring may be combined in the tapered so that they are not easily separated. Further, as shown inFIG. 47, the fastening ring11g4may be composed of a C-shaped metallic or synthetic resin spring member, lacking a part of a ring.

In the embodiments described hereinbefore; the main body frame14and support frame16are made of metal with high heat conductivity. They may be made of heat-resistant weather-resistant insulating synthetic, such as polybutylene terephthalate (PBT).

The engaging piece14dis formed in one piece of the synthetic main body frame14. The engaging piece14dmay be made of metal, formed like a hook separately from the main body frame14, and attached to one side of the main body frame14. The receiving place16dis formed on every side, or four sides of the rectangular support frame16. When the receiving place16dis provided on only one side of the support frame, not on four sides, the invention may be embodied. The lock mount piece16dmay be formed in one piece with the synthetic resin support frame16as described above, or a separate metallic lock mount piece formed like a groove is provided on four sides of the support frame16.

The lighting unit17may be provided in the main body frame14or light-emitting unit A. The lighting unit17may be installed on the back side of a ceiling, separately from the main body frame and light-emitting unit A.

A luminaire of the type recessed in an installation site on a ceiling is explained hereinbefore as an example of the invention. The invention may be applied to a luminaire to be directly installed on a ceiling. The embodiments described hereinbefore are preferable examples for explaining the invention. Therefore, the invention is not limited to the described embodiments. The design of the invention may be modified various forms without departing from the spirit and essential characteristics of the invention.