JP6064283B2 - Lighting device - Google Patents

Description

  The present invention relates to an illumination device that emits light with reduced light in a predetermined wavelength range.

  2. Description of the Related Art Conventionally, lighting apparatuses that irradiate an object to be irradiated with light in a predetermined wavelength region are known in fields where production effects such as store lighting are important (see, for example, Patent Document 1). As shown to Fig.6 (a), such an illuminating device 10 is provided in the light irradiation surface, LED20 which radiate | emits white light, the reflecting plate 30 which reflects the light from LED20 toward a light irradiation surface, and. A wavelength selective absorption unit 50 including a dye 40 that selectively absorbs light in a predetermined wavelength range. Light emitted from the illumination device 10 is light in which a predetermined wavelength component is absorbed by the dye 40 from the white light emitted from the LED 20. For example, when the dye 40 that absorbs yellow light is used, yellow light is used. It becomes white light with reduced components. It is known that white light in which such yellow light components are reduced makes the irradiated object look vivid.

  Further, as shown in FIG. 6B, there is also known an illuminating device 10 a based on the above illuminating device 10, in which a wavelength selective absorbing portion 50 is projected to the LED 20 side so as to cover the LED 20 without providing a reflector. ing. In such an illuminating device 10a, the white light emitted from the LED 20 is directly incident on the wavelength selective absorption unit 50, where a predetermined wavelength component is reduced by the dye 40 and then irradiated to the outside.

JP 2010-267571 A

  However, in the illumination device 10 as described above, the irradiation light luminance directly under the LED 20 is increased, resulting in luminance unevenness, and the occurrence of the luminance unevenness causes light absorption by the dye 40 between the LED 20 and the periphery thereof. Differences occur and uneven color occurs. In addition, since the pigment 40 in the vicinity of the LED 20 is strongly exposed to high-intensity light and heat from the LED 20, there is a possibility that the light absorbing function may be lost due to degeneration due to long-time use of the lighting device 10.

  On the other hand, in the illumination device 10a, in addition to the above-described problems, a difference occurs in the optical path length in the wavelength selective absorption unit 50 between the light L1 emitted from the LED 20 in the front direction and the light L2 emitted from the LED 20 to the side. . Therefore, a difference occurs in light absorption by the dye 40 between the light L1 and the light L2, and color unevenness occurs.

  The present invention solves the above-described problem, can reduce the occurrence of uneven brightness and color unevenness of irradiated light, and can prevent denaturation of a pigment located in the vicinity of a light source unit An object is to provide an apparatus.

The illumination device of the present invention includes a lamp having a light source unit and a wavelength selective absorption unit that selectively absorbs light in a predetermined wavelength region of light emitted from the light source unit, and the lamp has a flat plate shape. The wavelength selective absorption unit is disposed on the light irradiation surface of the lamp, the light source unit is disposed along the outer periphery of the lamp, and the light emitted from the light source unit is placed inside the lamp. A planar light guide that is guided toward the wavelength selective absorption unit while being guided toward the wavelength selective absorption unit, and the planar light guide is provided opposite to the wavelength selective absorption unit. A light guide surface that guides light toward the light source, and the light guide surface is formed in a curved shape such that a peripheral portion of the planar light guide is thick and a central portion of the planar light guide is thin It is characterized by being.

The illumination device further includes a frame body that accommodates the light source unit, the wavelength selective absorption unit, and the planar light guide and has an opening for emitting light from the wavelength selective absorption unit to the outside. When the lamp is viewed from the light irradiation surface side, the portion is disposed on the outer peripheral side of the opening, and the planar light guide is opposed to the light incident surface on which light from the light source portion is incident. It is preferable to have a total reflection surface that totally reflects light incident from the light incident surface at a location toward the inside of the planar light guide.

  It is preferable that the frame has a light reflecting surface on a surface facing the peripheral edge of the planar light guide.

  The wavelength selective absorption part preferably includes a tetraazaporphyrin-based dye having an absorption peak at a wavelength of 600 nm.

  According to the present invention, since the light from the light source unit is guided through the planar light guide and then enters the wavelength selective absorption unit, the light from the light source unit directly enters the wavelength selective absorption unit. In comparison with the above, the dye is not easily exposed to high-intensity light or heat, and the optical path length in the wavelength selective absorption section is uniform. Therefore, it is possible to reduce the occurrence of uneven brightness and color unevenness of the irradiation light, and it is possible to prevent the dye located near the light source part from being denatured.

The perspective view of the illuminating device which concerns on embodiment of this invention. Sectional drawing of the lamp | ramp which comprises the said illuminating device. The exploded perspective view of the said lamp. The figure which shows the chemical structure of the pigment | dye contained in the wavelength selection absorption part which comprises the said lamp. The figure which shows the spectral characteristic of the light irradiated from the said illuminating device. (A) is sectional drawing of the conventional illuminating device (lamp), (b) is sectional drawing of another conventional lamp.

  An illumination device according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the lighting device 1 is a desk lamp that is used on a desk or the like. The lighting device 1 includes a disk-shaped lamp 2, an arm 11 that holds the lamp 2 movably, and a base 12 that pivotally supports the arm 11 and is placed on a desk or the like. The lamp 2 has a light irradiation surface 2A on which one surface (the lower surface in the illustrated example) is irradiated with light.

  As shown in FIGS. 2 and 3, the lamp 2 includes a light source unit 3 disposed along the outer periphery of the lamp 2 and guides light emitted from the light source unit 3 toward the inside of the lamp 2. A planar light guide 4 led out to the light irradiation surface 2A side. The lamp 2 is disposed on the light irradiation surface 2A and selectively absorbs light in a predetermined wavelength range, and a heat radiating plate 6 for radiating heat generated by the light source 3 to the outside. The light source unit 3, the planar light guide 4, the wavelength selective absorption unit 5, and the frame body 7 that houses the heat sink 6 are further provided.

  The frame body 7 includes a flange 71 that covers the members 3 to 6 from the light irradiation surface 2A side, and a case main body 72 that engages the flange 71 and covers the members 3 to 6 from the opposite side of the light irradiation surface 2A. Have. The collar part 71 has a circular opening 73 for emitting the light from the wavelength selective absorption part 5 to the outside. In addition, illustration of the case main body 72 is abbreviate | omitted in FIG.

  The light source unit 3 includes a plurality of LEDs 31 and a wiring board 32 on which the LEDs 31 are mounted so that the optical axis of each LED 31 faces the light irradiation surface 2A. Each LED 31 is arranged in an annular shape at equal intervals from the outer periphery of the opening 7 of the frame body 7 and along the outer periphery of the lamp 2 when the lamp 2 is viewed from the light irradiation surface 2A side. . Each LED 31 includes a blue LED chip (not shown) that emits blue light having a main wavelength of 460 nm (see also FIG. 5), and a yellow phosphor that emits yellow light to orange light having a main wavelength of 575 to 620 nm when excited by the blue light. (Not shown). Each LED 31 emits white light by mixing blue light from a blue LED chip and yellow light to orange light from a yellow phosphor.

  The planar light guide 4 has a substantially disk shape with a peripheral edge extending to just below the LED 31. The planar light guide 4 is provided opposite to the LED 31 and receives a light incident surface 41 on which light from the LED 31 is incident, and the light from the LED 31 that is provided opposite to the light incident surface 41 and is incident from the light incident surface 41. And a total reflection surface 42 that totally reflects inward of the planar light guide 4. The light incident surface 41 is configured in a planar shape. The total reflection surface 42 has a parabolic shape, and is configured to totally reflect light from the LED 31 by adjusting the curvature thereof.

  In addition, the planar light guide 4 has a light derivation surface 43 that is provided opposite to the wavelength selective absorption unit 5 and guides light toward the wavelength selective absorption unit 5. The light guide surface 43 is configured in a curved shape such that the peripheral portion of the planar light guide 4 is thick and the central portion of the planar light guide 4 is thin.

  On the surface of the planar light guide 4 opposite to the light irradiation surface 2A side, a diffuse reflection sheet 8 having a light diffusion structure (not shown) for diffusing light and reflecting light is attached. . The light diffusion structure is formed by, for example, fine prism processing, silk printing, or laser dot processing, and is densely provided toward the center of the planar light guide 4. The planar light guide 4 is made of a translucent material that transmits light from the LED 31, and is made of, for example, acrylic resin, polycarbonate resin, or glass.

  The heat radiating plate 6 has a disc shape and is joined to the surface of the wiring board 32 opposite to the LED mounting surface. The heat sink 6 is made of a material having high thermal conductivity, for example, aluminum.

  The flange portion 71 of the frame body 7 has a light reflecting surface 74 that reflects light on a surface facing the peripheral edge portion of the planar light guide 4. The light reflecting surface 74 is formed, for example, by applying white coating to the collar portion 71.

  The wavelength selective absorption unit 5 has a disk shape larger than the opening 73 of the flange portion 71 and is disposed so as to cover the opening 73. The wavelength selective absorption unit 5 is made of a translucent material that transmits light from the LED 31 and includes a dye 51 having an absorption peak at a predetermined wavelength. In addition, you may perform the light-diffusion process by embossing etc. to the light irradiation surface 2A side surface of the wavelength selection absorption part 5, or light diffusion in addition to the pigment | dye 51 to the translucent material which comprises the wavelength selection absorption part 5 An agent may be added.

As shown in FIG. 4, the dye 51 is composed of a tetraazaporphyrin-based dye and has an absorption peak at a wavelength of 600 nm. Here, in the formula, R _{1 to} R ₈ are each a —R—O—Z group (wherein R is an alkylene group, Z is a linear, branched or cyclic alkyl group, a linear, branched or cyclic alkoxyalkyl group, substituted or non-substituted). A substituted aryl group, a substituted or unsubstituted aralkyl group, or a straight-chain, branched or cyclic halogenoalkyl group), hydrogen atom, halogen atom, cyano group, nitro group, straight-chain, branched or cyclic alkyl group, straight-chain or branched Or a cyclic alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aralkyloxy group, a linear, branched or cyclic halogenoalkyl group, linear, branched or Represents a cyclic halogenoalkoxy group, a substituted or unsubstituted amino group. At least one of R _{1 to} R ₈ is a —R—O—Z group, and R _{1 to} R ₈ adjacent to each other may form a carbocyclic aliphatic ring. M represents two hydrogen atoms, two monovalent metal atoms, a divalent metal atom, a trivalent substituted metal atom, a tetravalent substituted metal atom, or a metal oxide atom.

  Next, with reference to FIG. 2 described above again, a process in which light emitted from the LED 31 is irradiated to the outside will be described. Light emitted from the LED 31 (indicated by a broken arrow) enters the planar light guide 4 from the light incident surface 41 and is totally reflected by the total reflection surface 42 toward the inside of the planar light guide 4. . The light totally reflected by the total reflection surface 42 is further totally reflected by the light incident surface 41 and the light derivation surface 43, thereby being guided through the planar light guide 4 and reaching the light incident surface 41. A part (indicated by an alternate long and short dash line arrow) is diffused and reflected by the diffuse reflection sheet 8 and led out from the light lead-out surface 43. The light derived from the light deriving surface 43 is incident on the wavelength selective absorption unit 5, where yellow light to orange light having a wavelength of about 600 nm is absorbed by the dye 51, and then irradiated to the outside through the opening 73 of the frame body 7. Is done.

  In the above process, since the peripheral portion of the planar light guide 4 is thick and the central portion of the planar light guide 4 is thin, the light guided inside the planar light guide 4 The incident angle of the light to the light guide surface 43 becomes smaller toward the center of the planar light guide 4. For this reason, the light is easily led out from the light lead-out surface 43 toward the center of the planar light guide 4, so that the center of the lamp 2 can be prevented from becoming dark and the luminance of the irradiated light can be made uniform. .

  Further, when the lamp 2 is viewed from the light irradiation surface 2 </ b> A side, the light source unit 3 is disposed on the outer peripheral side of the opening 73 of the frame body 7 and faces the light incident surface 41 of the planar light guide 4. Since the total reflection surface 42 is provided, the light source unit 3 (LED 31) is not directly visible to the user. Thereby, glare can be prevented.

  Further, the light derived from the peripheral edge of the planar light guide 4 is reflected by the light reflecting surface 74 of the frame 7 and enters the planar light guide 4 again, so that the light utilization efficiency of the lamp 2 is improved. can do. Further, since the light diffusion structure of the diffuse reflection sheet 8 is densely provided toward the center of the planar light guide 4, the planar light guide 4 becomes closer to the center of the planar light guide 4. The light guided in the inside is more likely to be diffused by the diffusing structure and is easily led out from the light lead-out surface 43. This also makes it possible to prevent the central portion of the lamp 2 from becoming dark and make the illumination light luminance uniform.

  As shown in FIG. 5, the light emitted from the lamp 2 (shown by a solid line) as described above is compared with the light (shown by an alternate long and short dash line) emitted from a lamp not provided with the wavelength selective absorption unit 5. Thus, yellow light to orange light is reduced. Such light has the effect of conspicuous the object to be viewed, and for example, can clearly show characters written on white paper.

  As described above, according to the illumination device 1 of the present embodiment, the light from the light source unit 3 enters the wavelength selective absorption unit 5 after being guided through the planar light guide 4. Therefore, compared with the case where the light from the light source unit is directly incident on the wavelength selective absorption unit, the dye 51 is not easily exposed to high-intensity light or heat from the light source unit 3, and the optical path in the wavelength selective absorption unit 5 The length becomes uniform. Therefore, it is possible to reduce the occurrence of uneven brightness and color unevenness of the irradiation light, and to prevent the dye 51 located near the light source unit 3 from being denatured.

  Note that the lighting device according to the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the shape of the planar light guide is not limited to the above, and may be a flat plate shape in which the light incident surface and the light output surface are parallel to each other. Moreover, a pigment | dye is not limited to a tetraaza porphyrin type pigment | dye, Arbitrary pigment | dyes can be used according to the optical characteristic of irradiation light. Furthermore, it is good also as a structure which can replace | exchange wavelength selective absorption part and can use suitably the wavelength selective absorption part containing a pigment | dye which changes according to the use environment of an illuminating device.

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Lamp 2A Light irradiation surface 3 of a lamp Light source part 4 Planar light guide 41 Light incident surface 42 Total reflection surface 5 Wavelength selection absorption part 51 Dye 7 Frame 73 Opening 74 Light reflection surface

Claims (4)

A lighting device including a lamp having a light source unit and a wavelength selective absorption unit that selectively absorbs light in a predetermined wavelength region of light emitted from the light source unit,
The lamp is a flat plate shape,
The wavelength selective absorption unit is disposed on a light irradiation surface of the lamp,
The light source unit is disposed along the outer periphery of the lamp,
Further comprising a planar light guide that guides the light emitted from the light source part toward the wavelength selective absorption part while guiding the light toward the inside of the lamp ,
The planar light guide has a light derivation surface that is provided opposite to the wavelength selective absorption unit and guides light toward the wavelength selective absorption unit, and the light derivation surface is a peripheral edge of the planar light guide. A lighting device, characterized in that the portion is thick and the center of the planar light guide is thin . A frame that houses the light source unit, the wavelength selective absorption unit, and the planar light guide, and further includes an opening for emitting light from the wavelength selective absorption unit to the outside;
The light source unit is disposed on the outer peripheral side of the opening when the lamp is viewed from the light irradiation surface side.
The planar light guide totally reflects light incident from the light incident surface on a portion facing the light incident surface on which light from the light source unit is incident, toward the inside of the planar light guide. the lighting device according to claim 1, characterized in Rukoto which have a reflecting surface. The frame body, the illumination device according to 請 Motomeko 2 you further comprising a light reflecting surface on opposite side to the periphery of the planar light guide. The lighting device according to any one of claims 1 to 3, wherein the wavelength selective absorption unit includes a tetraazaporphyrin-based dye having an absorption peak at a wavelength of 600 nm .

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