JP5125562B2 - Lighting device - Google Patents

Description

  The present invention relates to a lighting device such as a downlight, which includes a light source having a semiconductor light emitting element such as an LED (light emitting diode) and is used by being embedded in a ceiling or the like.

  Conventionally, as an illuminating device that replaces a general incandescent bulb, an LED light source is disposed in an opening provided on the side facing the base in a case provided with a base and a reflective shade, and light emitted from the LED light source is emitted. An illumination device that reflects the light forward with a reflective shade is known (see, for example, Patent Document 1).

The LED light source of the lighting device includes a reflector having a plurality of holes for individually accommodating the LED bare chips on the printed circuit board, in which a plurality of LED bare chips are vertically and horizontally aligned and mounted in a two-dimensional arrangement. In addition, a transparent sealing resin is laminated on the reflecting plate. And what emits blue light thru | or ultraviolet light is used for a LED bare chip, and the yellow type fluorescent substance which converts blue light into white light is mixed in sealing resin. Patent Document 1 also describes an LED light source in which a plurality of LED bare chips are individually sealed with a sealing resin instead of being collectively sealed with a sealing resin. .
JP 2004-193357 A (paragraphs 0012-0030, FIGS. 1 to 8)

  In the illuminating device that replaces the incandescent bulb of Patent Document 1, unevenness in illuminance and uneven color are likely to occur on the irradiation surface irradiated with light reflected forward by the reflecting shade. This is due to the configuration of the LED light source.

  That is, while the LED bare chip of the LED light source is a point light source, the sealing resin mixed with the phosphor forms a surface light source that emits secondary light, and the light emission area of this surface light source is a point light source. Big in comparison. On the other hand, the reflecting surface of the reflecting shade that obtains a predetermined light distribution curve may be formed as a mirror surface.

  Compared to the case where light distribution is controlled using a lens, the configuration in which the light distribution is controlled by a reflecting surface made of a mirror surface eliminates the complexity of designing a lens suitable for each model in manufacturing an illumination device. Therefore, it is preferable in terms of cost advantage. At the same time, it is suitable for controlling the light by narrowing the opening of the beam, so that it is suitable for increasing the average illuminance on the irradiation surface of the target area. Furthermore, the configuration in which the light distribution is controlled by a mirror surface is preferable in that the reproducibility in manufacturing is high and the light distribution quality of the lighting device can be stabilized. By the way, controlling the light distribution by the diffuse reflection surface instead of the mirror surface is not only difficult to manufacture the mold when the reflection surface is unevenly formed by the molding die to produce a diffuse reflection surface. Since the uneven state changes each time the mold is maintained, it is difficult to stably maintain a stable light distribution quality of the lighting device.

  The intensity of light emitted from a point light source composed of an LED bare chip is large. For this reason, when the light distribution is controlled by a reflecting surface made of a mirror surface of a reflective shade that is not specially devised, the lower shape of the light distribution curve becomes a substantially conical shape, and the light distribution curve represented by the point where this conical shape converges Is located on the optical axis. With such a light distribution curve, the luminance at the central part of the illumination area is high and visually observed, so uneven illuminance on the irradiation surface is easily noticeable, and the light source color of the LED bare chip is blue at the central part of the illumination area In this case, the unevenness of color is likely to occur on the irradiated surface.

  Furthermore, in an arbitrary portion of the reflective shade having a reflecting surface composed of a mirror surface, light incident from the LED light source, that is, light having a small cross-sectional area and a high light intensity according to the size of the point light source, and a surface light source According to the size of the light, light having a large cross-sectional area and a small light intensity is incident and reflected according to the incident angle. Thereby, color unevenness occurs on the irradiated surface.

  Specifically, light from a point light source having a small cross-sectional area of the light beam is irradiated as pale white light having a strong blue wavelength component. Further, the light from the surface light source having a large cross-sectional area of the light beam has a strong yellow wavelength component and is irradiated as yellowish light surrounding the region irradiated with the pale light. Irradiated as white light surrounding a region irradiated with system light. For this reason, a lighter blue light color is more strongly expressed in the irradiated portion where pale light is overlapped than in the adjacent irradiated portion. Therefore, color unevenness occurs on the irradiated surface, and uneven illuminance based on the color unevenness also occurs.

  The objective of this invention is providing the illuminating device which can suppress the illumination intensity nonuniformity and color nonuniformity in an irradiation surface.

The invention according to claim 1 is a light source device including a device main body; a light source substrate and a plurality of light sources arranged at regular intervals around a central portion of the substrate , wherein the light source However, the semiconductor light-emitting element and the semiconductor light-emitting element are sealed and provided with a translucent material mixed with a phosphor that is excited by light emitted from the semiconductor light-emitting element and emits light of a predetermined wavelength. The light source device having a sealing member; a reflector disposed on a light projecting side of the light source device, the front wall being opened to face the front light wall individually facing the light sources A plurality of exit apertures and a reflecting surface that reflects the light incident from the light source and exits from the exit aperture, and the light distribution of the light exiting from the exit aperture is an inverse heart-shaped light distribution curve together with the reflecting surface is made such that, out each Openings have been arranged in the same arrangement as the light source so as to surround the central portion of the front wall, the area of the central portion of the front wall is the an area larger than the reflector of the exit opening; that provided with the It is characterized by.

The illuminating device of the invention of claim 1 is an illuminating device such as a downlight that is installed as an illuminating device that replaces, for example, a general incandescent bulb, or is inserted into an embedded hole provided in an installation portion such as a ceiling. Can be used as In the illumination device according to the first aspect of the invention, it is preferable to use an even number of light sources from the viewpoint of easily ensuring a balance of light distribution. Since at least one semiconductor light emitting element is required for one light source, a multi-chip light source using a plurality of semiconductor light emitting elements can be used.

  For example, an LED chip or an organic EL element can be used as the semiconductor light emitting element included in the light source of the illumination device according to the first aspect of the invention. When the semiconductor light emitting element is an LED chip, for example, a blue LED chip that emits blue light, an ultraviolet LED chip that emits ultraviolet light, and the like can be suitably used as the LED chip. It is also possible to use a combination of at least two types of LED chips. For example, when a lighting device that emits white light using a blue LED chip as a light emitting source is used, if a sealing member mixed with a phosphor that is excited by blue light and emits mainly yellow light is used. Well or alternatively, a phosphor that is excited by ultraviolet light to emit mainly red light, a phosphor that is excited by ultraviolet light to emit mainly green light, and a phosphor that is excited by ultraviolet light to emit mainly yellow light What is necessary is just to use the sealing member with which each fluorescent substance was mixed.

  In the invention of claim 1, a translucent sealing member that blocks the semiconductor light emitting element from the outside air and moisture to prevent the lifetime of the element from being reduced includes a translucent synthetic resin such as an epoxy resin, a silicone resin, and urethane. In addition to using a resin or the like, a transparent low-melting glass can also be used as a sealing member other than a resin.

  In the invention of claim 1, the mirror surface forming the reflecting surface of the reflector can be suitably provided by, for example, a deposited metal film. In order to form an inverted heart-shaped light distribution curve by the reflector according to the first aspect of the present invention, the beam angle of the light distribution curve of the light emitted from the output aperture is, for example, as in the second aspect of the present invention. It is desirable that the reflecting surface be designed so that the ratio of the light beam incident on the vertical angle of 0 degrees to 5 degrees is 7% to 10% of the total light flux while being 50 degrees to 60 degrees.

  According to the first and second aspects of the present invention, the light emitted from the light source having the semiconductor light emitting element and the phosphor-containing sealing member that seals the semiconductor light emitting element and incident on the reflecting surface composed of the mirror surface of the reflector is at the incident angle. Accordingly, the light is reflected toward the irradiation surface and emitted from the emission opening. The irradiated surface is illuminated with the light reflected in this way and the light directed to the irradiated surface without entering the reflecting surface from the light source.

  In this illumination, since the light distribution curve has an inverted heart shape by the light distribution control by the reflector, the light intensity at the center of the irradiation region is weakened and the light intensity around it is increased. As a result, the luminance at the central portion of the irradiation region becomes inconspicuous, so that the illuminance unevenness on the irradiation surface is suppressed, and accordingly, the emission color of the semiconductor light emitting element included in the light source is at the central portion of the irradiation region. Since it becomes inconspicuous, uneven color on the irradiated surface is also suppressed.

  According to a third aspect of the present invention, in the first or second aspect, the even number of the light sources are arranged symmetrically with respect to the optical axis, and the even number of the light sources are individually opposed to the light source. The even number of the reflection surfaces provided on the reflector are arranged symmetrically with respect to the optical axis.

  In the invention of claim 3, in the illumination device having a multi-light source, the virtual cross section when it is assumed that the light distribution formed by the light distribution control by the reflector on the vertical plane passing through the optical axis is cut off is arbitrary. Therefore, it is possible to obtain a highly uniform light distribution with no light distribution imbalance. Therefore, it is possible to suppress illuminance unevenness and color unevenness on the irradiated surface due to light distribution imbalance.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a light diffusing plate having a transmittance of 80% to 90% is disposed on the light emitting side of the reflector so as to cover the reflector. It is a feature.

  In the invention of claim 4, the light reflected by the reflecting surface is diffused by the light diffusing plate and applied to the irradiation surface. Due to this light diffusion, the light reflected by the reflecting surface of the reflector, and the light directed from the light source toward the irradiation surface without entering the reflecting surface and the light reflected by the reflecting surface of the reflector are mixed. Therefore, the light distribution of the light transmitted through the light diffusing plate is not the reverse heart-shaped light distribution formed by the reflector, but it can not only further improve the illuminance unevenness on the irradiation surface, but also the color unevenness on the irradiation surface. Can be improved effectively.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the frame body having the entrance and the exit facing the entrance is disposed on the light exit side of the reflector, and is recessed from the exit. The light diffusing plate is disposed on the incident port side.

  According to the fifth aspect of the present invention, it is possible to give the illuminating device a light blocking angle defined by a straight line passing through the light exit of the frame body and the light diffusing plate having different height positions. As a result, although the light diffuser shines brightly due to the high brightness of the lit light source, the direct view of the light diffuser is obstructed within the range of the light blocking angle, and the light diffuser is prevented from being visually observed. it can.

  According to the illumination device of the first to fourth aspects of the present invention, there is an effect that unevenness in illuminance and unevenness in color on the irradiated surface can be suppressed.

  According to the illuminating device of the invention of claim 5, in the invention of claim 4, there is an effect that it is possible to further suppress that the glare of the light diffusion plate is visually observed.

  An embodiment of the present invention will be described with reference to FIGS.

  Reference numeral 1 in FIGS. 1 and 2 denotes a lighting device, for example, a downlight. The downlight 1 is installed in a portion to be installed, for example, a ceiling 2 in a room of a building, and reference numeral 3 in FIG. 2 indicates an embedded hole opened in the ceiling 2.

  The downlight 1 includes a device main body 5, a power supply device 8, a terminal block 9, a light source device 11, a reflector 15, a light diffusion plate 21, a frame body 25, and a pair of mounting springs 31. Yes.

As shown in FIG. 1, the apparatus main body 5 is made of metal, for example, aluminum or an alloy thereof so as to serve as a heat radiating member that releases heat generated by an LED (light source), which will be described later, to the main body main part 6. 7 is formed by screwing. As shown in FIG. 2, the main body 6 has a power supply housing 6b on the upper side in FIG. 2 with a substantially circular bottom wall 6a as a boundary, and a light source housing 6c on the lower side of the bottom wall 6a in FIG. And has a plurality of heat dissipating fins 6d on the outer periphery. The light source housing portion 6c has a short, substantially cylindrical shape with an open lower end, and a plurality of connecting portions 6e are formed outside the light source housing portion 6c as shown in FIGS. The top plate 7 closes the upper end opening of the power supply accommodating portion 6b.

  A power supply device 8 and a terminal block 9 are attached to the device body 5. The power supply device 8 is accommodated in the power supply accommodating portion 6b. The power supply device 8 is formed by mounting various electrical components (not shown) on a power supply board. The terminal block 9 is attached to the side surface of the main body 6 of the top plate 7. The power supply device 8 has a function of controlling the lighting current of the LED described later, and the terminal block 9 supplies commercial AC power to the power supply device 8.

  As shown in FIG. 2, the light source device 11 is formed by mounting a plurality of light sources such as LEDs 13 on the surface of a light source substrate 12, specifically, six even numbers. These six LEDs 13 are arranged symmetrically with respect to an axis (not shown) passing through the center of the light source device 11 orthogonal to the light source substrate 12, in other words, centered on the optical axis of the light source device 11. Therefore, each LED 13 is arranged around the central portion of the light source substrate 12 at regular intervals, that is, at intervals of 60 degrees. This arrangement is shown in FIG.

  The light source substrate 12 has a substantially circular shape, and is disposed in the light source accommodating portion 6c such that the back surface on which the LEDs 13 are not mounted is brought into close surface contact with the lower surface of the bottom wall 6a. Therefore, by this surface contact, heat generated by light emission of the LED chip 13a, which will be described later, is conducted to the apparatus main body 5, and the temperature rise of the LED chip 13a is suppressed. The light source substrate 12 has a plurality of engaging portions such as grooves (not shown) on its peripheral portion. The light source device 11 is positioned with respect to the light source accommodating portion 6c by engaging the engaging portions with positioning portions such as ribs (not shown) provided on the inner surface of the light source accommodating portion 6c.

  Each LED 13 is formed to have a semiconductor light emitting element, for example, an LED chip 13a, a reflector 13b, and a translucent sealing member 13c, as illustrated in FIGS. A plurality of, for example, six LED chips 13a are used for one LED 13, and as shown in FIG. 5C, three are arranged in a row and the remaining three are arranged in a row, and These two rows are arranged in parallel and arranged inside the reflector 13b. These six LEDs 13 are arranged with their orientations set so that each of the columns formed by the LED chips 13 a extends along the radiation direction with respect to the center of the light source substrate 12 in the point-symmetric arrangement described above. ing.

  For example, an LED chip that emits blue light is used as the LED chip 13a of each LED 13, and these are mounted on one surface of the light source substrate 12 on which a conductor pattern (not shown) is formed, for example, by flip chip mounting. The electrical connection between each LED chip 13a and the conductor pattern can also be made by wire bonding. The plurality of LED chips 13a included in each LED 13 are connected in series, and the LEDs 13 are also connected in series. Accordingly, the LED chips 13 a mounted on the light source substrate 12 are connected in series with each other and are turned on all at once by being supplied with power through the power supply device 8.

  The reflector 13b is formed in a frame shape by, for example, white synthetic resin, surrounds each LED chip 13a, and is attached to the light source substrate 12 with an adhesive. As shown in FIGS. 5A and 5B, the inner peripheral surface of the reflector 13b is formed with a tapered surface that gradually increases in diameter as the distance from the light source substrate 12 increases. This taper surface functions as a light reflecting surface that reflects light in the light utilization direction, that is, when the ceiling 2 is used as a reference, downward.

  The sealing member 13c is made of, for example, a translucent resin, specifically a transparent silicone resin, and a phosphor is mixed in the sealing member 13c. The sealing member 13c is filled in the reflector 13b to seal the LED chip 13a. The phosphor mixed in the sealing member 13c is excited by the blue light emitted from the LED chip 13a and emits light of a predetermined wavelength, for example, a complementary color with respect to the blue light. A phosphor that mainly emits some yellow light is used. Therefore, each LED 13 using the LED chip 13a as a point-like primary light source projects white light from the sealing member 13c serving as a planar secondary light source.

  The LED 13 may be one in which the reflector 13b is omitted. In this case, the sealing member 13 c is provided by potting on the light source substrate 12, whereby the LED chip 13 a can be buried and sealed.

  The reflector 15 functions as a first light distribution control member that controls the light distribution of the light emitted from the LED 13, and in the light source housing 6c, the light projecting side of the LED 13, that is, the lower side of the LED 13 in FIG. Is arranged.

  The reflector 15 is formed by providing a reflecting surface 17 having a mirror surface on an electrically insulating synthetic resin molding 16. As shown in FIGS. 4A and 4B, the molded body 16 of the reflector 15 includes a front wall 16a, a peripheral wall 16b, a plurality of reflecting cylinder portions 16c, a screw receiving portion 16d, and a rib 16e.

  Specifically, the front wall 16a is formed in a circular shape having substantially the same size as the light source substrate 12. The front wall 16a has a step on the periphery. The peripheral wall 16b is bent from the periphery of the front wall 16a to the back side of the front wall 16a. The peripheral wall 16b has a plurality of grooves 16f. These grooves 16f are engaged with the above-described positioning portions (not shown) provided in plurality on the inner surface of the light source accommodating portion 6c. By this engagement, the reflector 15 is positioned with respect to the light source device 11 as the reflector 15 is positioned in the light source housing 6c.

  The plurality of reflecting cylinder portions 16c are provided on the inner side of the peripheral wall 16b and on the back side of the front wall 16a, and the number thereof is the same as the number of the LEDs 13 forming the light source, and the arrangement thereof is the LED 13 forming the light source. Is the same arrangement. Accordingly, the six reflecting cylinder portions 16c are arranged point-symmetrically with respect to the optical axis of the light source device 11, and specifically, are equally arranged around the center of the molded body 16 at intervals of 60 degrees. Yes. These reflecting cylinder portions 16c have an incident opening 16c1 opened at the projecting tip and an emission opening 16c2 opened in the front wall 16a. The incident aperture 16c1 is larger than the LED13. The entrance opening 16c1 and the exit opening 16c2 having a larger diameter face each other. The inner surface of the reflecting cylinder portion 16c, that is, the surface extending from the entrance opening 16c1 and the exit opening 16c2 is formed with a predetermined curve.

  The screw receiving portion 16d protrudes from the central portion on the back side of the front wall 16a. The ribs 16e are provided radially around the screw receiving portion 16d, and connect the screw receiving portion 16d and the reflecting cylinder portion 16c, and connect the reflecting cylinder portion 16c and the peripheral wall 16b. 2 and 4B, reference numeral 16g indicates escape grooves formed in the reflecting cylinder portion 16c continuously to the incident opening 16c1, and these escape grooves 16g are larger than the incident opening 16c1 and the LED 13. It is provided to escape the LED 13.

  The reflecting surface 17 is made of a metal reflecting film that is deposited on the inner surface of each reflecting tube portion 16c. These reflecting surfaces 17 are provided by evaporating aluminum, for example. In this case, the vapor deposition metal is continuously applied not only to the inner surface of the reflecting cylinder portion 16c but also to the inner surface of the reflecting cylinder portion 16c on the surface of the front wall 16a except for the peripheral portion forming the step of the front wall 16a. ing.

  The reflector 15 having the above-described configuration is disposed in the light source accommodating portion 6 c so as to overlap the light projecting side of the light source device 11, that is, on the light source mounting surface of the light source substrate 12. The reflector 15 is passed through the central portion of the bottom wall 6a from the power supply accommodating portion 6b toward the light source accommodating portion 6c and is screwed into the screw receiving portion 16d (see FIG. 2), thereby the device main body 5 It is fixed to.

  By this fixing, the light source substrate 12 is sandwiched between the reflector 15 and the bottom wall 6a. Each LED 13 of the light source device 11 individually faces each of the incident openings 16c1 of the respective reflection tube portions 16c of the reflector 15 thus fixed in association with the positioning. Therefore, the LED 13 and the emission opening 16c2 are opposed to each other.

  The reflection characteristic of each reflection surface 17 defined by the curve of the inner surface of the reflection cylinder portion 16c is such that the light distribution curve formed by the reflector 15 has an inverted heart shape drawn by a solid line in FIG. . For this reason, the beam angle α of the light emitted from the exit aperture 16c2 is 50 ° to 60 °, and the ratio of the luminous flux incident in the range where the vertical angle β is 0 ° to 5 ° is 7% to 10% of the total luminous flux. The reflecting surface 17 is designed to be%. Here, the vertical angle β is a solid angle that converges toward the intersection of the vertical line passing through 0 ° in FIG. 6, that is, the optical axis, and the horizontal line passing through 90 ° in FIG. pointing.

  Furthermore, the light distribution curve formed by the reflector 15 has an inverted heart shape. The lower end portion of the light distribution curve A shown by the solid line in FIG. 6 has a downward peak B and a ring shape indicating the maximum luminous intensity. The recess C has an upward recess C surrounded by the peak B, and the recess C is positioned on a vertical line (optical axis) passing through 0 ° in the light distribution curve A. The recess C and the optical axis The peak B located away from the peak has a continuous shape, and the upper part of the light distribution curve A indicates the shape converged at the intersection of the horizontal line passing through 90 ° and the vertical line in the light distribution curve A. ing.

The light diffusing plate 21 functions as a second light distribution control member for controlling the light distribution of the light emitted from the LED 13, and as shown in FIG. 2, the reflector 15 is disposed on the light emitting side of the reflector 15. Is disposed. The light diffusing plate 21 is formed by forming a raw material in which a light diffusing particle having a predetermined particle diameter is mixed with a transparent powder of an electrically insulating transparent material, for example, a transparent acrylic resin, into a disk having the same size as the front wall 16a. It is made. Therefore, each LED 13 of the light source device 11 is electrically insulated by the light diffusion plate 21 from the light emitting side. The light incident on the light diffusing plate 21 strikes the light diffusing particles dispersed inside the light diffusing plate 21, is diffused, and passes through the light diffusing plate 21.

The transmittance of the light diffusion plate 21 is 80% to 90%, preferably 85%. With such a transmittance, it is possible to obtain an appropriate diffusing action and appropriately suppress uneven color and uneven illuminance on the irradiated surface without significantly reducing the light utilization rate. Note that the transmittance exceeding 90% is not preferable in that the diffusion tends to be low and the unevenness of color and illuminance on the irradiated surface tends to be high. This is not preferable in that the utilization factor of light is greatly reduced.

  The frame body 25 functions as a third light distribution control member that controls the light distribution of the light emitted from the LED 13 and is made of, for example, a white, light-diffusing synthetic resin molding. As shown in FIG. 2, the frame body 25 has an entrance port 25 a and an exit port 25 b facing the entrance port 25 a. The exit port 25b is larger than the entrance port 25a, and the inner peripheral surface from the entrance port 25a to the exit port 25b forms, for example, a tapered reflecting surface formed of a part of a curved surface.

  The frame body 25 has an annular flange 26 projecting outward continuously from the emission port 25b. The annular flange 26 has a diameter larger than that of the embedded hole 3 in the ceiling 2, and is caught from below around the embedded hole 3 in a state where the downlight 1 is embedded and installed in the ceiling 2. The frame 25 has a fitting cylinder part 27, for example, an annular pressing part 28, and a plurality of connecting parts 29 (only one is shown in FIG. 1) on the back side of the tapered reflecting surface.

  The frame body 25 is connected by a connection screw (not shown) screwed into the connection portion 29 through the connection portion 6e of the main body main portion 6 in a state in which the fitting cylinder portion 27 is fitted to the outside of the light source housing portion 6c. , Connected to the apparatus body 5. In connection with this connection, the pressing portion 28 contacts the peripheral portion of the light diffusing plate 21, so that the peripheral portion of the light diffusing plate 21 is sandwiched between the reflector 15 and the pressing portion 28, whereby the light diffusing plate 21 is reflected by the reflecting member 15. Is fixed. At the same time, the frame body 25 is arranged on the light exit side of the reflector 15, so that the entrance port 25 a positioned behind the exit port 25 b is closed by the light diffusion plate 21 from the reflector 15 side. Yes.

  As shown in FIG. 2, a spring mounting portion 25 c is formed on the outer peripheral portion of the frame body 25 at a distance of 180 degrees. An attachment spring 31 is attached to each of the pair of spring attachment portions 25c. The portions other than the attachment portions of the pair of attachment springs 31 arranged corresponding to the radial direction of the frame body 25 are arranged at a first position arranged obliquely with respect to the apparatus main body 5 and the outer surface of the apparatus main body 5. It can move over the 2nd position arranged along.

  The downlight 1 configured as described above is inserted into the embedding hole 3 of the ceiling 2 with the pair of mounting springs 31 elastically deformed and disposed at the second position, and is pushed up until the annular flange 26 hits the ceiling 2. Thus, it is embedded in the ceiling 2. In this case, as the downlight 1 is pushed up, as the pair of attachment springs 31 released from the restraint are gradually inclined toward the first position, the root portions of the attachment springs 31 and The annular flange 26 sandwiches the edge of the embedding hole 3 so that the embedded state of the downlight 1 is maintained.

  The downward illumination by the downlight 1 includes light emitted from the LED 13 that is emitted downward without being reflected, and light that is reflected by the respective reflecting surfaces 17 of the reflector 15 and emitted downward. Is done by.

  In this illumination, the light distribution curve A has an inverted heart shape as shown by the solid line in FIG. In addition, as described above, the even number of LEDs 13 are arranged symmetrically with respect to the optical axis, and the reflecting surface 17 of the reflector 15 individually facing each LED 13 is also centered on the optical axis. The virtual cross section when assuming that the light distribution formed by the light distribution control by the reflector 15 is cut off on the vertical plane passing through the optical axis is substantially the same in any virtual cross section. And can. In other words, the light distribution is not unbalanced.

  In such a uniform light distribution, the presence of the upward concave portion C in the light distribution curve A means that the light intensity at the central portion of the irradiation region is weakened. Along with this, in the light distribution curve A, the fact that there is a downward peak B around the concave portion C means that the light intensity around the central portion of the irradiation region is enhanced.

  Thereby, in the state without the light diffusing plate 21, the luminance at the center of the irradiation region becomes inconspicuous, so that uneven illuminance on the irradiation surface is suppressed. At the same time, the blue color emitted by the LED chip 13a of the LED 13 is not noticeable at the center of the irradiation area, so that uneven color on the irradiation surface is also suppressed. Moreover, illuminance unevenness and color unevenness on the irradiated surface due to light distribution imbalance can also be suppressed.

  In addition, in this embodiment, the light distribution with a high degree of uniformity controlled as described above by the reflector 15 is transmitted to the light diffusion plate 21 immediately below the reflector 15. Due to the diffusing action, the light reflected by the reflecting surface 17 of the reflector 15 is mixed, and the light directed toward the irradiation surface without entering the reflecting surface 17 from the LED 13 and the reflected light reflected by the reflecting surface 17 are mixed. .

  Therefore, the light distribution of the light irradiated on the irradiation surface that has passed through the light diffusing plate 21 is not the reverse heart-shaped light distribution formed by the reflector 15, but the light distribution curve D drawn by the dotted line in FIG. Become.

Therefore, the illuminance unevenness on the irradiated surface can be further improved, and the color unevenness on the irradiated surface can be effectively improved.

  The downlight 1 includes a frame body 25, and a light diffusing plate 21 is disposed at a deep position in the frame body 25. Therefore, the light diffusing plate is mounted on the ceiling 2 when the downlight 1 is mounted. 21 is not arranged so as to be substantially flush with the ceiling 2. Since the light diffusing plate 21 shines brightly due to the high luminance of the emitted LED 13, the glare of the light diffusing plate 21 becomes conspicuous when it is arranged substantially flush as described above.

  However, since the light diffusing plate 21 is disposed above the ceiling 2, it is possible to give a light shielding angle indicated by the symbol θ in FIG. 2. This light blocking angle θ is defined by a straight line passing through the light exit plate 25b and the light diffusion plate 21 whose positions are different from each other in the vertical direction. Therefore, although the light diffusing plate 21 shines brightly, direct viewing of the light diffusing plate 21 is prevented in the range of the light blocking angle θ, and the glare of the light diffusing plate 21 can be suppressed from being visually observed.

  Further, the tapered reflecting surface of the frame 25 diffuses and reflects the light incident thereon, so that the irradiation surface can be illuminated by spreading the light around.

The perspective view which shows the downlight which concerns on one Embodiment of this invention. FIG. 2 is a side view of the downlight shown in FIG. The front view which shows the downlight of FIG. 1 in the state which removed the light diffusing plate and the frame. (A) is a perspective view which shows the molded object which the reflector of the downlight of FIG. 1 had seeing from the front side. FIG. 2B is a perspective view showing the molded body as seen from the back side. (A) is a front view which shows the light source with which the downlight of FIG. 1 is provided. (B) is sectional drawing which follows the F5B-F5B line | wire in FIG. 5 (A). (C) is sectional drawing which follows the F5C-F5C line | wire in FIG. 5 (A). The figure which shows the light distribution curve of the downlight of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Downlight (illuminating device), 5 ... Apparatus main body, 11 ... Light source device, 12 ... Light source board | substrate, 13 ... LED (light source) 13a ... LED chip (semiconductor light emitting element), 13c ... Sealing member, 15 ... Reflector 16a ... front wall 16 ... reflecting tube part 16c1 entrance opening 16c2 exit opening 17 ... reflecting surface 21 light diffuser plate 25 frame body 25a entrance 25b exit exit α Beam angle, β ... vertical angle, A ... light distribution curve , B ... downward peak, C ... upward dent

Claims (5)

The device body;
A light source device including a light source substrate and a plurality of light sources arranged at regular intervals around a central portion of the substrate, the light source device being disposed in the apparatus body, wherein the light source is a semiconductor light emitting element, and the semiconductor light emitting element The light source device having a translucent sealing member that is provided with a phosphor and mixed with a phosphor that is excited by light emitted from the semiconductor light emitting element and emits light of a predetermined wavelength When;
A reflector disposed on the light projecting side of the light source device, including a front wall, a plurality of emission openings that are individually opened on the front wall and opposed to the light sources, and light incident from the light source. The reflective surface has a reflecting surface that reflects and emits from the exit aperture, and the reflective surface is made so that the light distribution of the light emitted from the exit aperture becomes a reverse heart-shaped light distribution curve , The reflectors arranged in the same arrangement as the light source so as to surround the central portion of the front wall, and the reflector having an area of the central portion of the front wall larger than an area of the respective outgoing openings ;
An illumination device comprising:   The beam angle of the light distribution curve of the light emitted from the exit aperture is 50 degrees to 60 degrees, and the ratio of the luminous flux incident in the range of the vertical angle of 0 degrees to 5 degrees is 7% to 10% of the total luminous flux. The lighting device according to claim 1, wherein the reflection surface is designed so that the light distribution curve formed by the reflector has an inverted heart shape.   The even number of the light sources are arranged symmetrically with respect to the optical axis, and the even number of the reflection surfaces provided on the reflector individually facing the even number of the light sources are the light. The lighting device according to claim 1, wherein the lighting device is arranged point-symmetrically about an axis.   The illumination according to any one of claims 1 to 3, wherein a light diffusing plate having a transmittance of 80% to 90% is disposed on the light emitting side of the reflector so as to cover the reflector. apparatus.   A frame having an entrance and an exit opening facing the entrance is disposed on the light exit side of the reflector, and the light diffusing plate is disposed on the entrance opening side that is located behind the exit opening. The lighting device according to claim 4, wherein the lighting device is provided.

Images