JP2011096396A - Lighting fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting fixture capable of preventing deterioration of fixture efficiency due to a light-transmitting member in the lighting fixture having the light-transmitting member for protecting a light source. <P>SOLUTION: The lighting fixture includes a light source 3, a concave reflecting mirror 4 for concentrating light emitted from the light source 3, and the light-transmitting member 51 arranged on an opening of the reflecting mirror 4. The light-transmitting member 51 forms a hemi-spherical surface with a radius R wherein a distance from the center 31 of the light source 3 to an opening edge 41 of the reflecting mirror 4 is equal to R, and minute unevenness 6 is prepared on the surface of the light-transmitting member 51. Thus, interface reflection on the light-transmitting member 51 can be restrained, and light-transmitting efficiency of the light-transmitting member 51 can be improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lighting fixture having a light transmission member for protecting a light source or the like.

  2. Description of the Related Art Conventionally, some lighting fixtures using LEDs (light emitting diodes) as a light source have a plate-like light transmitting member on the front surface of the light source in order to protect the LED from electrostatic breakdown and wiring disconnection caused by user contact. The light transmitting member is made of a transparent material such as acrylic (PMMA), polycarbonate (PC), or glass so that the light emitted from the light source is transmitted, but a part of the light emitted from the light source is an interface with air. Therefore, the light reflected at the interface becomes a loss and decreases the efficiency of the instrument. For example, downlights using LEDs have a reduction in instrument efficiency of several percent by providing a light transmitting member.

  In order to suppress such interface reflection of the light transmitting member, for example, a multilayer film structure (for example, see Patent Documents 1 and 2) in which various films having different refractive indexes are stacked may be provided on the surface of the light transmitting member. It is done. However, since this multilayer film structure is highly dependent on the light incident angle and the wavelength dependency of the reflection suppression effect, the interference color appears strongly in the transmitted light, and the productivity is low and the manufacturing cost is high.

  Further, it is conceivable to provide a single layer film formed of a low refractive material film on the surface of the light transmission member to suppress interface reflection. However, the single layer film has a low antireflection effect and low adhesion to the light transmission member.

  In addition, micro unevenness that suppresses interface reflection is known (see, for example, Patent Documents 3, 4, and 5). However, the micro unevenness has a considerable incident angle dependency of the light transmittance. Therefore, even if the light transmitting member has minute irregularities on its surface, the light transmittance decreases as the incident angle of incident light increases. For this reason, it cannot be said that the prevention of a decrease in instrument efficiency is sufficient only by forming minute irregularities on the light transmitting member.

JP 11-312330 A JP 2000-76685 A JP 2007-304468 A JP 2006-130841 A JP 2006-276774 A

  This invention solves the said problem, and aims at preventing the fall of the instrument efficiency by a light transmissive member in the lighting fixture which has a light transmissive member for protection of a light source, etc.

  In order to achieve the above object, the invention of claim 1 is directed to a light source unit, a concave reflecting mirror that collects light emitted from the light source unit, and a light transmission member provided in an opening of the reflecting mirror, The light-transmitting member has a hemispherical surface with a radius from the center of the light source to the opening edge of the reflecting mirror, and has a minute unevenness on the surface of the member. It is.

  According to the first aspect of the present invention, the light emitted from the light source unit and directly incident on the light transmissive member is incident on the surface of the light transmissive member perpendicularly from the radial direction of the light transmissive member forming the hemispherical surface. Is suppressed. In addition, the light that is emitted from the light source unit, reflected by the reflecting mirror, and incident on the light transmitting member is suppressed from interfacial reflection by minute unevenness. For this reason, the light transmittance of a light transmissive member improves, and the fall of the instrument efficiency by a light transmissive member is prevented.

The perspective view which looked at the lighting fixture which concerns on one Embodiment of this invention from the downward direction. Sectional drawing of the lighting fixture. The top view of the front panel of the lighting fixture. Sectional drawing which shows the one light source part and the part corresponding to it in the lighting fixture. Sectional drawing which shows one light source part and the part corresponding to it in the lighting fixture of a comparative example.

  A lighting apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG.1 and FIG.2 shows the lighting fixture 1 of this embodiment. The luminaire 1 is a downlight, for example, and includes a housing 2, a plurality of light source units 3, and a concave reflecting mirror that is provided corresponding to the light source units 3 and collects light emitted from the light source unit 3. 4 and a front panel 5 attached to the front surface of the light source unit 3. The light source unit 3 and the reflection plate 4 are fixed to the substrate 21 and attached to the housing 2 via the heat dissipation sheet 22. The heat radiating sheet 22 conducts heat generated when the light source unit 3 is turned on to the housing 2 to radiate heat.

  The housing 2 includes a terminal block 23 to which an indoor wiring for power feeding is connected, an attachment spring 24 used at the time of ceiling mounting, and an annular frame 25 provided at the opening end of the housing 2. The housing 2 is inserted into an embedding hole opened in the ceiling, and is fixed to the ceiling member by an attachment spring 24 and a frame 25. The light source unit 3 is connected to the output side of the power circuit board 26 provided in the housing 2. The power circuit board 26 is connected to the terminal block 23 on the input side.

  FIG. 3 shows the front panel 5, and FIG. 4 shows one light source unit 3 and its corresponding part. The front panel 5 includes a light transmitting member 51 corresponding to the opening of the reflecting mirror 4 and a peripheral portion 52 formed integrally with the peripheral portion of the light transmitting member 51. The light transmissive member 51 is made of a light transmissive material, forms a hemispherical surface having a radius R from the center 31 of the light source unit 3 to the opening edge 41 of the reflecting mirror 4, and minute irregularities 6 are formed on the surface of the member. Have The peripheral portion 52 has a flat plate shape and does not have the minute unevenness 6.

  The housing 2 is made of a material that is difficult to break and can secure the strength of the lighting fixture 1, and is formed into, for example, a bottomed and uncovered cylindrical shape (see FIG. 2). As the material of the casing 2, plastic, plastic in which a reinforcing filler such as glass fiber is blended, metal such as aluminum alloy, iron, and magnesium alloy, wood, and the like are used.

  The number of the light source units 3 is determined by the illuminance required for the luminaire 1, and a plurality of the light source units 3 are illustrated in the present embodiment, but may be one. The plurality of light source units 3 are arranged on the substrate 21. For the light source of the light source unit 3, for example, an LED, an EL (electroluminescence), a fluorescent lamp, a cold cathode tube, or the like is used. LEDs and EL are desirable because they can be made small and thin, do not use mercury, and are excellent in light color variability, and LEDs are particularly desirable because of good color reproducibility. The light source unit 3 includes a white LED 32 as a light source and a heat radiating plate 33 that radiates heat generated by the white LED 32 (see FIG. 4). The light source unit 3 may include a plurality of LEDs having different spectral distributions, for example, LEDs that emit red light, green light, and blue light, and the light source unit 3 is controlled by controlling the energization current to each of these color LEDs. The color component of the emitted light may be changed. The center 31 of the light source unit 3 is the center of the light emitting surface of the LED in the present embodiment in which the light source unit 3 has one LED, and when one light source unit 3 has a plurality of LEDs, the light emitting surface of those LEDs. Is the geometric center of gravity.

  The reflecting mirror 4 is disposed corresponding to each of the light source units 3 and is shaped so that the emitted light from the light source unit 3 is efficiently irradiated and a desired light distribution is obtained by the irradiated light. The shaft 34 is a rotationally symmetric axis, has a rotating quadratic reflection surface opened in the irradiation direction, and has a circular opening in plan view. An optical thin film having a light reflecting layer such as aluminum or silver may be formed on the reflecting surface in order to increase the reflectance.

  The base material of the reflecting mirror 4 is a material that can withstand the heat generated by the light source unit 3, for example, resin, metal, or glass. When a resin is used as the base material, as the resin, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), which are typical thermoplastic resins. , Thermoplastic polyimide (PI), polyetherimide (PEI), polycarbonate (PC), liquid crystal polymer (LCP), syndiotactic polystyrene (SPS), and the like. Examples of the thermosetting resin include unsaturated polyester (UP) generally used as a material for bulk molding compound (BMC). To these resins, various additives such as inorganic fillers may be added in order to improve light reflection performance, heat resistance, strength, light resistance and the like. Moreover, the shaping | molding method which shape | molds a base material in a predetermined shape is a shaping | molding method used by general resin shaping | molding, for example, injection molding, compression molding, vacuum forming, and pressure forming.

  When a metal is used as the base material of the reflecting mirror 4, the metal generally includes an Al-based alloy, an Mg-based alloy, an Fe-based alloy, and the like. The forming method is, for example, spinning, pressing, die casting, thixo molding, and the like, and is selected in consideration of the shape to be formed with the metal substrate.

  When glass is used as the base material of the reflecting mirror 4, the molding method is typically press working or blow working. After the base material is molded, if there is processing oil, a mold release agent, residue of the scum during molding, etc. on the surface, it may be removed by a physical or chemical method. As the surface treatment of the molded glass, the undercoat layer and the topcoat layer may be formed by coating with a spray method or the like and then cured by irradiation with infrared rays, hot air, ultraviolet rays, electron beams or the like.

  For the front panel 5, a material is appropriately selected according to the degree of heat and ultraviolet rays emitted from the light source unit 3, the installation environment of the lighting fixture 1, and the like, for example, a silicon oxide such as borosilicate glass or crystal as a main component. Alternatively, an inorganic material such as sapphire or the like mainly composed of aluminum oxide, or a transparent organic material such as acrylic (PMMA), polycarbonate, or polystyrene is used. Examples of the method for molding the front panel 5 include injection molding, compression molding, transfer molding, vacuum molding, and pressure molding when the material is plastic. In the case where the material is glass, typical examples include press processing and blow processing.

  The light transmissive member 51 is covered with the opening of the reflecting mirror 4 for preventing damage to the light source unit 3, preventing moisture, preventing contamination, improving design, and the like, and an incident surface 51a on which light emitted from the light source unit 3 enters. The light incident on the light transmitting member 51 has an emission surface 51b through which the light is emitted into the air, and the incidence surface 51a forms a hemispherical surface. The hemispherical surface may not be a mathematically exact hemispherical surface, and may be a partial spherical surface having a smaller solid angle than the hemispherical surface. The center of the hemispherical surface substantially coincides with the center 31 of the light source unit 3, and the radius R of the hemispherical surface is a distance from the center 31 of the light source unit 3 to the opening edge 41 of the reflecting mirror 4. If the height distance from the center 31 of the light source unit 3 to the opening surface of the reflecting mirror 4 is H and the diameter (opening diameter) of the opening of the reflecting mirror 4 is D, the radius R is calculated by the following equation.

  The thickness of the light transmitting member 51 is substantially uniform, and the emission surface 51b also forms a hemispherical surface. Further, the thickness of the light transmission member 51 is set to a sufficiently small value compared to the radius R, and the radius of the hemispherical surface of the emission surface 51b is substantially the same as R.

  The minute irregularities 6 are periodic structures in which minute irregularity-shaped unit structures are arranged in an array, and are formed on at least one of the incident surface 51 a and the emission surface 51 b of the light transmission member 51, preferably on both surfaces. . The uneven shape of the minute unevenness 6 is a weight shape with a pitch equal to or less than the wavelength of the light whose interface reflection should be suppressed among the light emitted from the light source unit 3 and incident on the light transmitting member 51 and having an aspect ratio of 1 or less. Is desirable.

  The method for forming the minute irregularities 6 includes mold forming of the light transmitting member 51, etching of the surface of the light transmitting member 51, embossing, electron beam drawing method, UV nanoimprint method, etc., and the UV nanoimprint method is desirable. In the UV nanoimprint method, a UV curable paint is applied to the surface of the light transmitting member 51, a mold made of quartz glass or the like having a desired concavo-convex shape is pressed against the UV curable paint, and then UV (ultraviolet) is passed through the mold. Irradiation is performed to cure the UV curable coating material, and the fine irregularities 6 are formed.

  In the luminaire 1 configured as described above, the light emitted from the light source unit 3 is incident on the incident surface 51a of the light transmitting member 51 through the two types of optical paths L1 and L2, and is transmitted through the inside of the light transmitting member 51. Then, the light is emitted from the emission surface 51b into the air. As indicated by the optical path L1, the light emitted from the light source unit 3 and directly incident on the light transmitting member 51 enters the surface of the light transmitting member 51 perpendicularly from the radial direction of the light transmitting member 51 forming a hemispherical surface. Therefore, the incident angle becomes 0 and interface reflection is suppressed. The incident angle is 0 regardless of the position of the incident point 53 on the light transmission member 51 in the optical path L1. Further, as indicated by the optical path L 2, the light that is emitted from the light source unit 3, reflected by the reflecting mirror 4, and incident on the light transmitting member 51 is suppressed from interfacial reflection by the minute unevenness 6. When the minute unevenness 6 is formed on the incident surface 51a, the interface reflection of the light incident on the light transmitting member 51 is suppressed, and when the minute unevenness 6 is formed on the outgoing surface 51b, the light transmitting member 51 in the air. The interface reflection of the light emitted to is suppressed. For this reason, the light transmissive member 51 has improved light transmittance due to the shape of the semispherical member and the minute irregularities 6 on the surface, and the light transmissive member 51 is prevented from lowering the efficiency of the luminaire 1.

(Example)
An evaluation test was conducted on one example of the present invention and four comparative examples for comparison. Table 1 shows the evaluation conditions and evaluation results in this evaluation test.

  In the evaluation test, the evaluation conditions were changed for the light transmissive member. The evaluation items were the total light transmittance (%) of the light transmitting member and the appliance efficiency (%) of the lighting fixture 1. The total light transmittance of the light transmitting member was measured with a self-recording spectrophotometer (U-4100, manufactured by Hitachi High-Technologies Corporation), and the measured value at 555 nm was taken as the light transmittance. Moreover, the light transmission member was incorporated in the lighting fixture 1, and the appliance efficiency was measured. As the lighting fixture 1, an LED downlight (NNN21010, manufactured by Panasonic Electric Works Co., Ltd.) was used. This LED downlight has a total of six white LEDs as light sources and has a wattage of 7.8 W.

  In the embodiment, H of the reflecting mirror 4 is 13 mm and D is 20 mm (see FIG. 4). The light transmissive member 51 was molded from polycarbonate (AZ1900T, manufactured by Idemitsu Petrochemical Co., Ltd.) by an injection molding method so as to form a hemispherical surface. The radius R of the hemispheric surface was 16.4 mm calculated from H and D of the reflecting mirror 4, and the thickness of the light transmitting member 51 was 1 mm. A UV curable coating (PAK-02, manufactured by Toyo Gosei Co., Ltd.) was applied to the incident surface 51a and the exit surface 51b of the light transmitting member 51, and the micro unevenness 6 was formed by the UV nanoimprint method. The minute unevenness 6 is a periodic structure having a unit structure having a cone shape with a height of 200 nm and a pitch of 200 nm.

  FIG. 5 shows a configuration of one light source unit and a corresponding part in the comparative example. The light transmitting member 151 in the comparative example was formed by molding the same polycarbonate as in the example, the incident surface 151a and the emission surface 151b were flat, and the plate thickness between both surfaces was 1 mm. Conditions other than the light transmitting member 151 were the same as in the example. The figure shows a case where the light transmitting member 151 has minute irregularities 6. Since the incident surface 151a is a flat surface, as shown by the optical path L101, the light emitted from the light source unit 3 and directly incident on the light transmitting member 151 is incident as the incident point 153 is closer to the periphery of the light transmitting member 151. The angle θ increases.

  In Comparative Example 1, the fine irregularities 6 were not formed on the light transmitting member 151.

  In Comparative Example 2, the minute unevenness 6 was formed only in the incident surface 151a in a circular region having a diameter Da = 20 mm. Other conditions were the same as in Comparative Example 1.

  In Comparative Example 3, the minute unevenness 6 was formed in a circular region having the same diameter Da = Db = 20 mm on both the entrance surface 151a and the exit surface 151b. The other conditions were the same as in Comparative Example 2.

  In Comparative Example 4, the diameter of the circular region of the minute unevenness 6 formed on the exit surface 151b was Db = 25 mm, and was larger than the diameter Da = 20 mm of the circular region of the minute unevenness 6 formed on the incident surface 151a. The other conditions were the same as in Comparative Example 3.

  As shown by the numerical values of the evaluation results in Table 1, the comparative example 1 is provided with the light transmissive member 151 that does not have the minute unevenness 6 as compared with the lighting device without the light transmissive member (reference). Efficiency decreased by 6.0%.

  Compared with Comparative Example 1, the comparative example 2 is formed with the minute irregularities 6 only on the incident surface 151a of the light transmitting member 151, so that the total light transmittance of the light transmitting member 151 is increased by 2.0%, and the instrument efficiency is increased. Increased by 2.0%.

  Compared with Comparative Example 2, the comparative example 3 has the micro light unevenness 6 formed on the exit surface 151b in addition to the entrance surface 151a of the light transmission member 151, so that the total light transmittance of the light transmission member 151 is 2. Increased by 0% and appliance efficiency increased by 2.0%.

  In Comparative Example 4, compared with Comparative Example 3, the diameter Db of the circular region of the minute unevenness 6 formed on the exit surface 151b is larger than the diameter Da of the circular region of the minute unevenness 6 formed on the incident surface 151a. The total light transmittance of the light transmitting member 151 was increased by 0.5%, and the instrument efficiency was increased by 1.0%.

  Compared with Comparative Example 3, the working example improved the instrument efficiency by 1.5% by molding the light transmitting member 51 so as to form a hemispherical surface, and also increased by 0.5% compared to Comparative Example 4. , 99.5%.

  From the above evaluation results, it was confirmed that in addition to forming minute irregularities on the surface of the light transmissive member, the light transmissive member has a hemispherical surface, thereby further preventing deterioration in instrument efficiency due to the light transmissive member. .

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. For example, the lighting fixture 1 of the present invention is not limited to a downlight, and is, for example, a lighting fixture that is installed indoors, in an entrance, under an eaves, etc. in a public facility, commercial facility, factory, condominium or detached house. The fixture form may be a base light, a ceiling light, a bracket, a spotlight, a tunnel light, or the like.

DESCRIPTION OF SYMBOLS 1 Lighting fixture 3 Light source part 31 Center of light source part 4 Reflective mirror 41 Opening edge 51 of reflective mirror Light-transmitting member 6 Small unevenness

Claims (1)

A lighting apparatus comprising: a light source unit; a concave reflecting mirror that collects light emitted from the light source unit; and a light transmitting member provided at an opening of the reflecting mirror,
The light illuminating member has a hemispherical surface having a radius from a center of the light source unit to an opening edge of the reflecting mirror, and has a minute unevenness on a surface of the member.

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