JP2014067616A - Illuminating device and a holder used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illuminating device having a light-emitting element which achieves both broadening of an effective light-emitting region and uniformizing of luminance in the effective light-emitting region.SOLUTION: An illuminating device 100 includes: a light-emitting element 110; a holder 120 for covering the light-emitting element 110; and a light guide rod 130 held by the holder 120. The holder 120 includes a light source opposite part 122 which reflects emitted light of the light-emitting element 110 to an end surface of the light guide rod 130 held by it. On an outside surface of the light source opposite part 122, a transmissivity adjustment sheet 124 is arranged. The transmissivity of the light which emits to the outside of the holder 120 passing through the light source opposite part 122 from the inside of the holder 120 is adjusted to be lower than the transmissivity of the light which emits to the outside of the holder 120 passing through a holding part 123 adjacent to the light source opposite part 122 by the transmissivity adjustment sheet 124.

Description

  The present invention relates to a lighting device that uses a light emitting element as a light source and can be used in place of a fluorescent tube, and a holder used therefor.

  In recent years, lighting devices (for example, LED bulbs and LED fluorescent tubes) that use light-emitting diodes (hereinafter also referred to as “LEDs”) as light sources have been used as lighting devices to replace light bulbs and fluorescent tubes from the viewpoint of energy saving and environmental conservation. It has come to be. As such an illuminating device, for example, as shown in FIG. 1, an illuminating device having LEDs 10 and 11 and an annular light guide plate 13 that covers the LEDs 10 and 11 and forms an annular light guide and a light emitting portion. It is known (see, for example, Patent Document 1). The light guide plate 13 includes inclined surfaces 17 and 18 that reflect part of light emitted from the LEDs 10 and 11 in the optical axis direction of the LEDs 10 and 11 in a direction orthogonal to the optical axis and transmit the remaining part. The light reflected by the inclined surfaces 17 and 18 is incident on the inside of the light guide plate 13 from the end surface of the light guide plate 13 facing the LEDs 10 and 11, travels inside the light guide plate 13, and goes outward from the outer surface of the light guide plate 13. Exit.

  Moreover, as said illuminating device, as shown, for example in FIG. 2, the illuminating device which has the LED mounting base 21 and the light guide tube 22 is known (for example, refer patent document 2). The LED mounting base 21 includes an LED that emits light toward the light guide tube 22 to be mounted on the LED mounting base 21. The LED mounting base 21 is made of, for example, an aluminum extruded material. The light guide tube 22 is, for example, a transparent columnar member, and the LED mounting base 21 allows the optical axis LA of the LEDs arranged on the LED mounting base 21 to coincide with the long axis CA of the light guide tube 22. Supported. By using the LED mounting base 21 and the light guide tube 22 as one light emitting unit and connecting a plurality of light emitting units, the length of the lighting device can be freely extended.

JP 2004-296611 A JP 2012-79568 A

  In the illumination device described in Patent Document 1, the outer surface of the portion of the light guide plate 13 facing the LEDs 10 and 11 (hereinafter referred to as “opposing portion”) is also an effective light emitting region, but the outer surface is a bright portion. Prone. As a means for preventing the outer surface from becoming a bright portion, it is conceivable to increase the thickness of the facing portion. However, when the facing portion is thickened, the short wavelength component of the light incident on the facing portion is absorbed. For this reason, light containing the remaining long wavelength component at a high ratio is emitted from the facing portion, color unevenness may occur, and brightness unevenness may occur. In the illuminating device described in Patent Document 2, the portion of the LED mounting base 21 is outside the effective light emitting region and tends to be a dark portion. As described above, the conventional lighting device can form a longer light emitting region with fewer light emitting elements, but has a problem that luminance unevenness occurs in the LED mounting portion that is a joint of the light guide member. .

  The present invention has been made in view of the above points, and provides an illumination device having a light emitting element, in which an effective light emitting region is broadened and brightness is uniformized in the effective light emitting region. With the goal.

  Another object of the present invention is to provide a holder for use in the lighting device.

  A holder for an illuminating device according to the present invention is a holder main body for covering a light emitting element and holding a rod-shaped light guide member, and adjacent to the light source facing part for covering the light emitting element. A holder body into which the light guide member is inserted, the holder body having light transmittance, and the transmittance of light emitted to the outside through the light source facing part through the holder part. The light source facing portion includes an inclined surface inclined toward the holding portion on its inner wall surface, and the light source facing portion When covering the light emitting element, a part of the light emitted from the light emitting element and reaching the inclined surface is reflected by the inclined surface toward the holding portion and the remaining portion is transmitted.

  An illumination device according to the present invention includes a light emitting element, a holder that covers the light emitting element and has an end in a direction that intersects the optical axis of the light emitting element, and an end of the holder toward the direction that intersects the optical axis of the light emitting element. And a cover that covers the holder and the light guide member and diffuses and transmits the light emitted from the holder and the light guide member, the holder according to the present invention described above The structure which is a holder is taken.

  According to the present invention, it is possible to achieve both broadening of the effective light emitting region and uniform luminance within the effective light emitting region.

FIG. 1A is a plan view of the illumination device described in Patent Document 1, and FIG. 1B is an enlarged view of a main part of a cross section taken along line BB shown in FIG. 1A. It is a front view which shows the structure of the illuminating device of patent document 2. FIG. 3A is a plan view of a lighting device according to an embodiment of the present invention, and FIG. 3B is a front view of the lighting device. It is a side view of the illuminating device which concerns on one Embodiment of this invention. 5A is a cross-sectional view taken along the line AA shown in FIG. 3B, and FIG. 5B is a cross-sectional view taken along the line BB shown in FIG. 3A. It is sectional drawing of CC line shown by FIG. 3B. 7A is a plan view of a holder according to an embodiment of the present invention, FIG. 7B is a front view of the holder, FIG. 7C is a side view of the holder, and FIG. 7D is a side view of the holder. It is a bottom view. 8A is a plan view of a holder body according to an embodiment of the present invention, FIG. 8B is a cross-sectional view taken along line BB shown in FIG. 8A, and FIG. 8C is a side view of the holder body. FIG. 8D is a bottom view of the holder body. 9A is a graph showing the luminance of the holder of the lighting apparatus according to the embodiment of the present invention, and FIG. 9B is a diagram showing the positions where the luminance peaks a to c in FIG. 9A are detected in the holder. . FIG. 10A is a graph showing the luminance of the holder and the light guide member in the illumination device, and FIG. 10B is a diagram showing the position where the luminance peak d in FIG. 10A is detected in the holder. FIG. 11A is a graph showing the luminance of the holder and the light guide member in the lighting device, and FIG. 11B is a diagram showing the position at which the luminance peaks b and d in FIG. 11A are detected in the holder. It is a figure which shows the transmittance | permeability of visible light in the transmittance | permeability adjustment part which concerns on one Embodiment of this invention. It is a figure which shows the transmittance | permeability of visible light in the holder main body which concerns on one Embodiment of this invention, and a holder. FIG. 14A is a diagram schematically showing an optical path of light emitted from the light emitting element in the vicinity of the holder of the lighting apparatus according to one embodiment of the present invention and FIG. 14B, and FIG. 14B is a view from the light emitting element in the lighting apparatus. It is a figure which shows schematically the optical path of the emitted light. FIG. 15A is a plan view showing an arrangement of a holder and a light guide member according to another embodiment of the present invention, and FIG. 15B is a front view showing an arrangement of the holder and the light guide member.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, a lighting device that can be used in place of a fluorescent tube will be described as a representative example of the lighting device of the present invention.

[Configuration of lighting device]
FIG. 3A is a plan view of lighting device 100 according to an embodiment of the present invention, and FIG. 3B is a front view of lighting device 100. FIG. 4 is a side view of the lighting device 100. 5A is a cross-sectional view taken along the line AA shown in FIG. 3B, and FIG. 5B is a cross-sectional view taken along the line BB shown in FIG. 3A. FIG. 6 is a cross-sectional view taken along line CC shown in FIG. 3B.

  As illustrated in FIGS. 3 to 6, the lighting device 100 includes a light emitting element 110, a holder 120, a light guide rod 130, a heat sink 140, a cover 150, and a frame 160. The illumination device 100 is formed in a substantially cylindrical shape. In the present specification, the “optical axis of the light emitting element” refers to the traveling direction of light at the center of the three-dimensional light flux from the light emitting element. When there are a plurality of light emitting elements, it refers to the traveling direction of light at the center of a three-dimensional light beam from the plurality of light emitting elements.

  The light emitting elements 110 are light sources of the lighting device 100, and a plurality of light emitting elements 110 are arranged on the substrate 115 attached to the heat sink 140 along the axial direction (longitudinal direction) of the lighting device 100. The light emitting element 110 is disposed between the light guide rods 130 along the longitudinal direction in the longitudinal direction of the lighting device 100 (the direction of the arrow X in FIG. 5). The light emitting element 110 is a light emitting diode (LED) such as a white light emitting diode. The heat sink 140 and the substrate 115 are made of, for example, a metal having high thermal conductivity such as aluminum or copper. When the substrate 115 does not require high thermal conductivity, a resin substrate in which a glass nonwoven fabric is impregnated with an epoxy resin may be used as the substrate 115.

  In the direction X, the holder 120 covers the light emitting element 110 at the center, and holds the light guide rod 130 at both ends. The holder 120 will be described in detail later.

  The light guide rod 130 is a rod-shaped light guide member having light transmittance and light scattering properties. The light guide rod 130 is held at the end of the holder 120 and is disposed between the light emitting elements 110 along the direction X. The light emitted from the light emitting element 110 and the light reflected by the holder 120 are incident on the end surface of the light guide rod 130. That is, the end surface 132 of the light guide rod 130 functions as an incident surface. The light that has entered the light guide rod 130 travels through the light guide rod 130 by a predetermined distance, and then is emitted from the outer peripheral surface (side surface) 134 of the light guide rod 130. That is, the outer peripheral surface 134 of the light guide rod 130 functions as an exit surface.

  In the present embodiment, the shape of the light guide rod 130 is a cylindrical shape, but the shape of the light guide rod 130 is not particularly limited as long as it has a shape having an end surface 132 and an outer peripheral surface 134. The shape may be a truncated pyramid shape. Further, the length and thickness of the light guide rod 130 are appropriately set according to the application, the intensity of light emitted from the light emitting element 110, and the like. For example, the lighting device 100 includes a first light guide rod that is held at both ends by two holders 120 and a second light guide that is held at one end by one holder 120 and has half the length of the first light guide rod. Two kinds of light guide rods may be included.

  The light guide rod 130 is formed by, for example, injection molding, extrusion molding, cast molding, or the like. The material of the light guide rod 130 is not particularly limited as long as it can transmit light having a desired wavelength. For example, the material of the light guide rod 130 is a light transmissive resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), and epoxy resin (EP); or glass. Further, scatterers such as beads may be dispersed in the light transmissive resin or glass. Desired scattering characteristics can be imparted to the light guide rod 130 by dispersing the scatterers at an appropriate concentration in the light guide rod 130. Moreover, you may perform a light-diffusion process (for example, roughening process) to the outer peripheral surface 134 of the light guide rod 130. FIG.

  The heat sink 140 is disposed along the direction X over the entire length of the lighting device 100. The heat sink 140 is formed with a circuit for connecting the light emitting element 110 and an external power supply circuit. The heat sink 140 is made of a metal having high thermal conductivity such as aluminum or copper. The heat sink 140 has a function of cooling the light emitting element 110. The shape of the heat sink 140 is not particularly limited as long as the function is achieved.

  The cover 150 is formed in a substantially cylindrical body that lacks a portion of the circumferential wall of the cylinder in the circumferential direction over the entire length of the cylinder. The cover 150 covers the holder 120 and the light guide rod 130 on the heat sink 140 at positions away from the holder 120 and the light guide rod 130 by the side edges of the cover 150 being fitted into the recesses of the heat sink 140. . The cover 150 has light transmittance and light scattering properties. The cover 150 allows the light reaching the cover 150 from the outer peripheral surface 134 of the light guide rod 130 and the outer surface of the holder 120 to diffuse and transmit to the outside.

  The shape of the cover 150 is not particularly limited as long as it can cover the holder 120 and the light guide rod 130 as described above. For example, in the present embodiment, the shape of the cover 150 is a shape in which a part of the cylinder is cut out over the entire length of the cylinder, but may be a cylindrical shape, a rectangular tube shape, a flat plate shape, or the like.

  The material of the cover 150 is not particularly limited as long as it has light transparency. Examples of the material of the cover 150 include light transmissive resins such as polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), and styrene / methyl methacrylate copolymer resin (MS). Also, the means for imparting light diffusing power to the cover 150 is not particularly limited. For example, light diffusion treatment (for example, roughening treatment) may be performed on the inner surface or outer surface of the cover 150, or scatterers such as beads may be dispersed in the light transmissive resin.

  The frame 160 is disposed at both ends of the lighting device 100. The frame 160 has a notch for fitting into the heat sink 140 at the lower part in FIG. 5B. The frame 160 is externally fitted to the cover 150 and is fitted to the lower portion of the end portion of the heat sink 140 at the notch. The frame 160 is made of a metal having high thermal conductivity such as aluminum or copper. When the lighting device 100 is used as an alternative to the conventional fluorescent tube, since the electrodes are formed on the frame 160, the frame 160 is formed of an insulating material.

[Configuration of Holder 120]
7A is a plan view of the holder 120, FIG. 7B is a front view of the holder 120, FIG. 7C is a side view of the holder 120, and FIG. 7D is a bottom view of the holder 120.

  The holder 120 has a holder main body 121, a transmittance adjustment sheet 124 and a claw 125. The holder main body 121 includes a light source facing part 122 and a holding part 123.

  8A is a plan view of the holder main body 121, FIG. 8B is a cross-sectional view taken along the line BB shown in FIG. 8A, FIG. 8C is a side view of the holder main body 121, and FIG. It is a bottom view of the holder body 121.

  The holder main body 121 is formed in a substantially semicylindrical shape. In this specification, the substantially semi-cylindrical shape includes a semi-cylindrical shape and may further include a side wall connected to a side edge of the semi-cylindrical. That is, the shape of the cross section perpendicular to the axial direction (direction X) of the holder main body 121 is a bell-like shape (inverted U shape). The axis of the holder body 121 is, for example, an axis of a semi-cylindrical part. The shape of the holder body 121 is not limited to a substantially semi-cylindrical shape as long as it covers the light emitting element 110 and can hold the light guide rod 130 at the end, and may be, for example, a cylindrical shape.

  The holder main body 121 is molded from a resin having optical transparency. The holder main body 121 may further have light reflectivity. As resin which comprises the holder main body 121, transparent or white resin is mentioned, for example. For example, the material of the holder body 121 is a resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), or epoxy resin (EP); glass. The light reflective holder main body 121 can be manufactured by molding the holder main body 121 using a light reflective material (white resin or the like). Alternatively, the light-reflective holder body 121 can be manufactured by imparting light reflectivity to the surface of the holder body 121 manufactured using various materials having light transmittance. As a method for imparting light reflectivity, for example, the surface of the holder main body 121 is coated on the surface of the holder main body 121 by applying a light reflective paint (for example, white paint), attaching a metal thin film, or depositing a metal. Forming a metal layer and dispersing the scatterers in the material of the holder body 121.

  The light source facing portion 122 is a portion that covers the light emitting element 110 and is disposed at a position adjacent to the holding portion 123. Since the holder main body 121 has the holding portions 123 at both ends in the direction X, the light source facing portion 122 is located in the center portion between the holding portions 123 and 123 of the holder main body 121 in the direction X.

  A pair of inclined surfaces 122a and a ridgeline 122b formed therebetween are formed on the inner wall surface of the light source facing portion 122 along the circumferential direction of the inner wall surface. The inclined surface 122 a faces both the lower side in FIG. 8 and the holding portion 123, and is inclined toward the holding portion 123. The ridgeline 122b is located on a virtual plane orthogonal to the arrow X. Each of the pair of inclined surfaces 122a is in a symmetric position with respect to the virtual plane.

  For example, when the light emitting element 110 is arranged with respect to the holder main body 121 so that the optical axis LA is included in the virtual plane, the light is emitted from the light emitting element 110 so as to be reflected toward the holding unit 123. The surface 122a and the ridgeline 122b are designed. In the cross section including the axis of the holder main body 121, the inclined surface 122a may be a surface represented by a straight line or a surface represented by a curve.

  The resin material forming the light source facing portion 122 may be the same as or different from the resin material forming the portion other than the light source facing portion 122 of the holder main body 121. For example, the light source facing part 122 can be formed of a resin having light reflectivity. Examples of the resin constituting the light source facing portion 122 include, for example, a white resin and a transparent resin in which scatterers are dispersed. The light source facing portion 122 may have a reflective layer on the inclined surface 122a. In this case, the light source facing portion 122 can be formed of a material that does not have light reflectivity.

  The holding part 123 forms an end part in the direction X of the holder main body 121. At the end of the inclined surface 122a, a flange portion 122c formed from a plane perpendicular to the direction X extending from the inclined surface 122a is formed. The end of the holder main body 121 in the direction X with respect to the flange portion 122c is a holding portion 123 into which the light guide rod 130 is inserted. As described above, the holding portion 123 is adjacent to the light source facing portion 122 through the flange portion 122c. The light source facing portion 122 is further formed with a notched portion 122d in which a portion of the light source facing portion 122 at the end of the ridgeline 122b is notched.

  The transmittance adjusting sheet 124 functions as a transmittance adjusting unit that lowers the transmittance of light emitted to the outside through the light source facing portion to be lower than the transmittance of light emitted to the outside through the holding portion. The transmittance adjustment sheet 124 is disposed on the outer surface of the light source facing portion 122 along the circumferential direction of the light source facing portion 122. A known member that lowers the light transmittance can be used for the transmittance adjusting sheet 124. Examples of the material of the transmittance adjusting sheet 124 include white resin such as white acrylic resin. The transmittance adjustment sheet 124 is, for example, a white resin sheet.

  The thickness of the transmittance adjusting sheet 124 is, for example, about 100 to 300 μm. The holder main body 121 formed in a complicated shape including the inclined surface 122a is preferably formed by injection molding or cutting. When such a means is used, the holder body 121 is usually thicker than the transmittance adjustment sheet 124 in consideration of the filling property and strength of the material resin of the holder body 121. For reasons of manufacturing the holder main body 121 as described above, it is preferable that the minimum thickness of the light source facing portion 122 is thicker than the thickness of the transmittance adjusting sheet 124. The minimum thickness of the light source facing portion 122 is the thickness of the portion where the thickness of the light source facing portion 122 is minimum, for example, the thickness of the light source facing portion 122 at the edge of the inclined surface 122a on the holding portion 123 side. .

  On the other hand, the minimum thickness of the light source facing portion 122 is preferably small from the viewpoint of preventing the occurrence of uneven color of light in the lighting device. When the holder main body 121 is manufactured by injection molding or the like, the material of the holder main body 121 usually includes a light transmittance required for the holding portion 123 and a light reflectivity required for the reflection surface 122a of the holder main body 121. Both are necessary. In order to prevent the occurrence of luminance unevenness in the holder main body 121 of the illuminating device, it is necessary to suppress the light transmission amount in the light source facing portion 122 as compared with the light transmission amount in the holding portion 123 as described later. . When the thickness of the light source facing portion 122 is increased and the amount of light transmitted through the light source facing portion 122 is reduced, the yellowish light is compared to other portions of the holder body 121 (for example, the holding portion 123). The light emitted from the light source facing portion 122 may cause color unevenness. This is because light having a short wavelength is absorbed more as the optical path length of light propagating through the holder body 121 is longer. In order to prevent the occurrence of the color unevenness, it is preferable that the holder main body 121 is made as thin as possible, and the light transmittance at the light source facing portion 122 is adjusted (lowered) by the transmittance adjusting sheet 124. For example, when the holder main body 121 is manufactured by injection molding, the minimum thickness of the light source facing portion 122 is preferably 1.0 mm or less.

  Further, the fact that the light reflectance of the holder main body 121 is smaller than the light reflectance of the transmittance adjusting sheet 124 increases the light emitted from the holding portion 123 (the portion covering the light guide rod 130), and the lighting device 100. This is preferable from the viewpoint of preventing occurrence of uneven brightness. From such a viewpoint, the light reflectance of the transmittance adjusting sheet 124 is preferably 85 to 98%, and the holder main body 121 preferably has a light reflectance lower than that. In the embodiment of the present invention, the holder body 121 has a light transmittance of 30% at a thickness of 0.5 mm.

  Further, the illumination device 100 is that the transmittance of light in the transmittance adjustment sheet 124 when the transmittance adjustment sheet 124 and the light source facing portion 122 have the same thickness is smaller than the light transmittance in the light source facing portion 122. This is preferable from the viewpoint of increasing the overall brightness and preventing the occurrence of uneven brightness in the holder 120 portion. As described above, when the holder main body 121 is made of a material having a transmittance necessary for the holding portion 123, the amount of light transmitted through the light source facing portion 122 is increased more than necessary. For this reason, it is preferable to adjust the transmittance of light emitted to the outside through the light source facing portion 122 by the transmittance adjustment sheet 124 having a low transmittance. From such a viewpoint, it is preferable that the light transmittance in the transmittance adjusting sheet 124 is 2 to 15%. The transmittance adjusting sheet 124 passes through the light source facing portion 122 from the inside of the holder main body 121 to the holder 120. It is preferable that it is a member which adjusts the transmittance | permeability of the light radiate | emitted outside from 1 to 5%. When the transmittance of light in the transmittance adjustment sheet 124 exceeds 15%, the transmittance of light emitted from the inside of the holder main body 121 through the light source facing portion 122 to the outside of the holder 120 is in the range of 1 to 5%. In order to do so, it is necessary to reduce the light transmittance of the holder body 121. As described above, since light having a short wavelength is absorbed more in the holder main body 121, when the holder main body 121 is thickened to reduce transmittance, color unevenness due to yellowing of emitted light occurs.

  The claws 125 are portions that further protrude downward from the four corners of the holder main body 121 in FIGS. 8B and 8C. The claw 125 has a flange portion 125a formed by a flat surface extending toward the side of the holder main body 121, and a tapered portion 125b in which the thickness of the claw 125 gradually decreases from the flange portion 125a toward the tip of the claw 125. .

  In the lighting device 100, the substrate 115 is disposed on the heat sink 140, the light emitting element 110 is disposed on the substrate 115, the holder 120 is disposed on the light emitting element 110 so as to cover the light emitting element 110, and is guided to the holding portion 123 of the holder 120. The optical rod 130 is inserted, the cover 150 is fitted into the heat sink 140, and the frame 160 is fitted into the ends of the heat sink 140 and the cover 150. The holder 120 is placed on the light emitting element 110 at an intended position by inserting a claw 125 into a positioning hole formed in the heat sink 140. Accordingly, the ridgeline 122b is arranged so as to be positioned on the optical axis LA of the light emitting element 110, the holding portion 123 is positioned at an end in a direction orthogonal to the optical axis LA of the light emitting element 110, and the light guide rod 130 is It is held by the holding unit 123 in a direction orthogonal to the optical axis LA. The order of the above steps can be changed as long as the lighting device 100 can be assembled. For example, the arrangement of the substrate 115 on the heat sink 140 and the arrangement of the light emitting element 110 on the substrate 115 may be performed in this order, or may be performed in reverse. Further, the arrangement of the holder 120 on the heat sink 140 and the insertion of the light guide rod 130 into the holder 120 may be performed in this order, may be performed in reverse, or may be performed simultaneously.

[optical properties]
FIG. 9 is a diagram illustrating the optical characteristics of the holder 120. FIG. 9A shows the brightness of the holder 120 when the light emitting element 110 emits light with the cover 150 removed from the lighting device 100. The vertical axis represents luminance (L), and the horizontal axis represents measurement position coordinates (P). FIG. 9B shows a state in which the cover 150 is removed from the lighting apparatus 100, and shows a portion where a luminance peak in FIG. 9A is detected. The end portions of the light guide rods 130 and 130 inserted in the holding portion 123 are covered with a black sheet and shielded from light. The luminance is measured using a luminance meter “CA-2000” manufactured by Konica Minolta. In FIG. 9A, “a” to “c” indicate main peaks in the luminance distribution of the holder 120, respectively. In FIG. 9B, “a” indicates the position of the end face of the light guide rod 130 on one end side of the holder 120 where the peak a is detected, and “b” indicates the other end of the holder 120 where peak b is detected. “C” indicates the position of the optical axis LA of the light emitting element 110 where the peak c is detected. As shown in FIG. 9A, peak a and peak b are large and peak c is small.

  10 and 11 are diagrams showing optical characteristics of the holder 120 and the light guide rod 130. FIG. FIGS. 10A and 11A show the brightness of the holder 120 and the light guide rod 130 when the light emitting element 110 emits light with the cover 150 removed from the lighting device 100. The vertical axis represents luminance (L), and the horizontal axis represents measurement position coordinates (P). FIG. 10B and FIG. 11B both show a state where the cover 150 is removed from the illumination device 100. Of the light guide rods 130 inserted into the holding part 123, only the end of one light guide rod 130 is covered with a black sheet and shielded from light. The luminance is measured using a luminance meter “CA-2000” manufactured by Konica Minolta. As the light guide rod 130, three kinds of light guide rods having different concentrations of scatterers dispersed in the light guide rod 130 are used. In FIG. 10A and FIG. 11A, “AX” (broken line) indicates the luminance distribution of the holder 120 and the light guide rod 130 when the light guide rod having the lowest dispersion density of the scatterers is used. “EX” (one-dot chain line) indicates the luminance distribution of the holder 120 and the light guide rod 130 when the light guide rod having the highest dispersion density of the scatterers is used. “CX” (solid line) indicates the luminance distribution of the holder 120 and the light guide rod 130 when a light guide rod having a scatterer dispersion concentration between them is used. In FIG. 10A, “d” indicates one peak due to the light guide rod 130 in the luminance distribution of the holder 120. In FIG. 10B, “d” indicates that the peak d is detected in the holding unit 123. Indicates the position.

  As shown in FIG. 10A and FIG. 11A, when the concentration of the scatterers of the light guide rod 130 is high, the brightness of the holding portion 123 is higher, and the brightness of the portion of the light guide rod 130 away from the holder 120 is higher. Lower. For this reason, in the light guide rod 130, the difference in luminance between the portion near the holder 120 and the portion far from the holder 120 increases. Such a difference in luminance in the light guide rod 130 may cause luminance unevenness of the lighting device 100.

  When the concentration of the scatterer of the light guide rod 130 is low, the brightness of the portion near the holder 120 in the light guide rod 130 is lowered. However, the brightness of the portion near the holder 120 and the brightness far from the holder 120 are low. There is almost no difference. However, the difference between the brightness of the holder 120 and the brightness of the light guide rod 130 increases. Such a difference in luminance between the holder 120 and the light guide rod 130 may cause luminance unevenness of the lighting device 100.

  In “CX”, in the light guide rod 130, the luminance of the portion near the holder 120 is relatively high, and the difference in luminance between the portion near the holder 120 and the portion far from the holder 120 is also relatively small. Moreover, the difference between the brightness of the holder 120 and the brightness of the light guide rod 130 is also relatively small. Accordingly, unevenness in brightness of the lighting device 100 is unlikely to occur. In this way, by appropriately adjusting the concentration of the scatterers of the light guide rod 130, the occurrence of uneven brightness in the lighting device 100 can be suppressed.

  FIG. 12 is a diagram illustrating the transmittance of the transmittance adjustment sheet 124. The vertical axis represents the transmittance (T), and the horizontal axis represents the wavelength (λ) of the incident light. The thickness of the transmittance adjusting sheet 124 used for the transmittance measurement is 188 μm. As shown in FIG. 12, the transmittance of light in the transmittance adjusting sheet 124 is 2.0 to 3.5% in the light wavelength range of 450 to 850 nm.

  FIG. 13 is a diagram showing the transmittance of the holder 120. The vertical axis represents the transmittance (T), and the horizontal axis represents the wavelength (λ) of the incident light. In FIG. 13, “NA” (broken line) indicates the light transmittance in the holder 120 (light source facing portion 122) that does not have the transmittance adjusting sheet 124, and “AD” (solid line) indicates the transmittance adjusting sheet 124. The light transmittance in the holder 120 (light source facing part 122) to which is attached is shown. In the measurement of transmitted light, light is incident on the ridgeline 122b of the light source facing portion 122. As shown in FIG. 13, in the light wavelength range of 450 to 850 nm, the light transmittance in the holder 120 without the transmittance adjusting sheet 124 is 13.9 to 18.1%, and the transmittance adjustment is performed. The light transmittance in the holder 120 having the sheet 124 is 1.5 to 2.7%. With the transmittance adjusting sheet 124, the light transmittance at the light source facing portion 122 is sufficiently lowered than the light transmittance at the holding portion 123. Therefore, the luminance at the center portion of the holder main body 121 is lowered, and in the lighting device 100, the occurrence of luminance unevenness in which the holder 120 portion is a bright portion is prevented.

  FIG. 14 is a diagram schematically showing an optical path in the illumination device 100. 14A is a diagram schematically illustrating an optical path of light emitted from the light emitting element 110 in the holder 120 and the vicinity thereof, and FIG. 14B is a schematic diagram of an optical path of light emitted from the light emitting element 110 in the illumination device 100. FIG.

  As shown in FIG. 14A, the light emitted from the light emitting element 110 reaches the light source facing portion 122 and the end surface 132 of the light guide rod 130. Most of the light that has reached the light source facing portion 122 is reflected by the inclined surface 122a, and the remaining light passes through the light source facing portion 122 and the transmittance adjusting sheet 124 and is emitted from the holder 120. The light reflected by the inclined surface 122 a is emitted toward the holding unit 123 and reaches the end surface 132 of the light guide rod 130. The light that reaches the end surface 132 enters the light guide rod 130 from the end surface 132. A part of the light incident on the light guide rod 130 travels in the light guide rod 130, and the remaining part is emitted from the outer peripheral surface 134 of the light guide rod 130. As described above, the light transmittance in the holder 120 is appropriately adjusted by, for example, the transmittance adjusting sheet 124, and the luminance of the light guide rod 130 in the longitudinal direction of the light guide rod 130 is determined by, for example, the concentration of the scatterers. Adjusted appropriately. Therefore, the brightness balance between the holder 120 and the light guide rod 130 is appropriately maintained.

  Both the holder 120 and the light guide rod 130 have specific light distribution characteristics. For example, as shown in FIG. 14B, the light distribution characteristic of the holder 120 has a peak in the direction of the angle α with respect to a plane (horizontal virtual plane) perpendicular to the optical axis LA, and the light distribution characteristic of the light guide rod 130 is Suppose that it has a peak in the direction of the angle β with respect to the horizontal virtual plane. When α is larger than β, on one end side of the holder 120, the distance between the arrival position of the light reaching the cover 150 at the angle α and the arrival position of the light reaching the cover 150 at the angle β between the arrival position of the light at the cover 150. In addition, a gap (symbol G in FIG. 14B) occurs in the direction X. However, the light of the light emitting element 110 disposed at the end (not shown) of the light guide rod 130 on the other end side of the holder 120 travels in the light guide rod 130 on the other end side of the holder 120 and is emitted at an angle β to be spaced. When it reaches G, it can become light that supplements the brightness of the gap G. For this reason, generation | occurrence | production of the dark part by said clearance gap G is prevented, and it can prevent that the nonuniformity of the brightness of the illuminating device 100 arises. From the viewpoint of preventing the occurrence of such uneven brightness, the length of the holding portion 123 in the direction X is preferably as short as possible within the range in which the light guide rod 130 can be held, for example, about 2.5 mm. preferable.

[effect]
The illuminating device 100 reflects a part of the light emitted from the light emitting element 110 disposed between the light guide rods 130 by the inclined surface 122a facing the light emitting element 110 to enter the light guide rod 130 and emits the light. It has a configuration in which the light transmittance of the light source facing part 122 through which the remaining part of light passes can be appropriately adjusted. For this reason, the brightness | luminance of the holder 120 does not become high too much. In this way, the lighting device 100 achieves both broadening of the effective light emitting area and uniform luminance in the effective light emitting area. The light transmittance in the light source facing portion 122 can be easily and appropriately adjusted by the transmittance adjusting sheet 124. Therefore, most of the holder 120 excluding the transmittance adjusting sheet 124 can be integrally manufactured by molding a single resin material having light transmittance and light reflectivity. For this reason, the holder 120 and the illuminating device 100 using the same are advantageous from the viewpoint of productivity.

[Modification]
In the embodiment described above, the transmittance of the light emitted to the outside of the holder 120 through the light source facing portion 122 is adjusted by the transmittance adjustment sheet 124. The light transmittance in the light source facing portion 122 can be adjusted to the desired transmittance separately from the light transmittance in the holding portion 123. For example, by applying other resin materials prepared so as to have different light transmission properties only to the light source facing portion 122 at the time of integral molding, the light transmittance at the light source facing portion 122 is set to the desired transmission. It is possible to adjust to the rate. By such means, the same function as the transmittance adjustment sheet 124 can be further imparted to the light source facing portion 122. As described above, the transmittance of the light emitted to the outside of the holder 120 through the light source facing portion 122 can be adjusted by means other than the transmittance adjusting sheet 124.

  When the light emitting element 110, the holder 120, and the light guide rod 130 are one light emitting unit, the lighting device 100 can be configured to be longer by connecting the light emitting units in series. For example, the lighting device shown in FIG. 15 has a configuration in which two sets of lighting devices 100 shown in FIGS. As described above, the length of the lighting device 100 can be freely adjusted in units of light emitting units.

  In the above-described embodiment, the inclined surface 122a is a surface represented by a pair of straight lines sandwiching the ridgeline 122b in the cross section along the direction X of the holder main body 121. In the present invention, these shapes can be modified as long as the light emitted from the light emitting element 110 can be reflected toward the holding portion 123. For example, the ridgeline 122b may not be located on a virtual plane. For example, the inclined surface 122a may be a curved surface represented by a curve in the cross section.

  In the above-described embodiment, the light guide rod 130 is held in a direction orthogonal to the optical axis LA, but the optical axis LA is within a range in which light emitted from the light emitting element 110 can enter the light guide rod 130. You may change the direction of the light guide rod 130 with respect to.

  The shape of the illumination device 100 when viewed from above is an elongated rectangle, but in the present invention, it is also possible to configure an illumination device having an annular planar shape. In addition, for example, by holding the light guide rod 130 only on one end side of the holder 120 and closing the other end side, it is possible to configure an illumination device including only the above-described one light emitting unit as a light emitting unit.

  Since the lighting device of the present invention can be used in place of a fluorescent tube or the like, it can be widely applied to various lighting devices.

10,11 LED
DESCRIPTION OF SYMBOLS 13 Light guide plate 17,18 Inclined surface 21 LED mounting base 22 Light guide tube 100 Illuminating device 110 Light emitting element 115 Board | substrate 120 Holder 121 Holder main body 122 Light source opposing part 122a Inclined surface 122b Ridge line 122c, 125a Flange part 122d Notch part 123 Holding part 124 transmittance adjustment sheet 125 claw 125b taper portion 130 light guide rod 132 end surface 134 outer peripheral surface 140 heat sink 150 cover 160 frame

Claims (6)

A holder main body for covering the light emitting element and holding the rod-shaped light guide member, the light source facing part for covering the light emitting element, and the light guide member formed adjacent to the light source facing part, A holder main body having a light transmitting property,
A transmittance adjusting unit that lowers the transmittance of light emitted to the outside through the light source facing portion, and lower than the transmittance of light emitted to the outside through the holding unit;
The light source facing portion includes an inclined surface inclined toward the holding portion on an inner wall surface thereof, and is emitted from the light emitting element and reaches the inclined surface when the light source facing portion covers the light emitting element. A part of the light is reflected by the inclined surface toward the holding part and the remaining part is transmitted;
Holder for lighting device. The transmittance adjusting unit is a sheet or film disposed on the outer surface of the light source facing unit,
The thickness of the transmittance adjusting part is smaller than the minimum thickness of the light source facing part,
The holder according to claim 1. The light reflectance of the transmittance adjusting unit is greater than the light reflectance of the holder body,
The holder according to claim 2. The holder according to claim 2, wherein when the transmittance adjusting unit and the light source facing portion have the same thickness, the light transmittance at the transmittance adjusting unit is smaller than the light transmittance at the light source facing portion. . The shape of the holder body is a substantially semi-cylindrical shape,
The holder according to claim 1, wherein the light source facing portion includes a pair of the inclined surfaces inclined toward the holding portion and a ridge line formed between the pair of reflection surfaces on an inner wall surface thereof. A light emitting element;
A holder that covers the light emitting element and has an end in a direction intersecting the optical axis of the light emitting element;
A rod-shaped light guide member held at the end of the holder in a direction intersecting the optical axis of the light emitting element;
A cover that covers the holder and the light guide member and diffuses and transmits light emitted from the holder and the light guide member;
Have
The holder is a holder according to any one of claims 1 to 5,
Lighting device.

Images