WO2011083779A1 - Optical element and light-emitting device - Google Patents

Optical element and light-emitting device Download PDF

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Publication number
WO2011083779A1
WO2011083779A1 PCT/JP2011/050007 JP2011050007W WO2011083779A1 WO 2011083779 A1 WO2011083779 A1 WO 2011083779A1 JP 2011050007 W JP2011050007 W JP 2011050007W WO 2011083779 A1 WO2011083779 A1 WO 2011083779A1
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WO
WIPO (PCT)
Prior art keywords
light
emitting device
incident
prism
optical element
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PCT/JP2011/050007
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French (fr)
Japanese (ja)
Inventor
恵一 望月
Original Assignee
日東光学株式会社
小池　康博
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Application filed by 日東光学株式会社, 小池　康博 filed Critical 日東光学株式会社
Publication of WO2011083779A1 publication Critical patent/WO2011083779A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V5/00—Refractors for light sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V7/00—Reflectors for light sources
    • F21V7/0091—Reflectors for light sources using total internal reflection
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
    • G02B19/0028—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed refractive and reflective surfaces, e.g. non-imaging catadioptric systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
    • G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
    • G02B19/0061—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED
    • G02B19/0066—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED in the form of an LED array
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G02B5/0226—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures having particles on the surface
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0294—Diffusing elements; Afocal elements characterized by the use adapted to provide an additional optical effect, e.g. anti-reflection or filter
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/04—Prisms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2103/00—Elongate light sources, e.g. fluorescent tubes
    • F21Y2103/10—Elongate light sources, e.g. fluorescent tubes comprising a linear array of point-like light-generating elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems

Definitions

  • the present invention relates to an optical element and a light emitting device.
  • LEDs Light Emitting Diodes
  • a plurality of LEDs are arranged at a predetermined interval, and a long transparent body is arranged close to the LEDs along the direction in which the LEDs are arranged.
  • a light scattering layer for scattering light is applied.
  • This light-emitting device is supposed to be able to uniformly irradiate light from an LED (see Patent Document 1).
  • an object of the present invention is to provide an optical element and a light-emitting device that can make the illuminance of illumination light more uniform and reduce glare when a plurality of light sources such as LEDs are used as the light source.
  • an optical element of the present invention has a light guide part that exhibits a triangular prism, and one of the three side surfaces of the light guide part is an incident surface on which light is incident, and the other one
  • the light incident on the side surface is a total reflection surface that totally reflects the light, and the remaining one side surface is the light output surface that emits the light that is totally reflected.
  • the incident surface includes a plane including the total reflection surface and a plane including the output surface.
  • a first prism portion including a plurality of first triangular prisms having a ridge portion with a ridge line direction in a direction intersecting with.
  • the base angle ⁇ 1 of the first triangular prism is not less than 20 degrees and not more than 70 degrees, and the interval P1 between adjacent ridges of the plurality of first triangular prisms is from the bottom surface of the first triangular prism.
  • the height to the ridge is H1, it is preferable that (2 ⁇ H1 / tan ⁇ 1) ⁇ P1 ⁇ (10 ⁇ H1 / tan ⁇ 1).
  • the light scattering particles are translucent silicone particles having a particle size of 2 ⁇ m to 9 ⁇ m, and have a scattering parameter corresponding to a scattering coefficient by the light scattering particles.
  • turbidity it is preferable that ⁇ > 0.01.
  • a second prism portion including a plurality of second triangular prisms arranged along the arrangement direction of the plurality of first triangular prisms is provided on the emission surface.
  • the base angle ⁇ 2 of the second triangular prism portion is not less than 50 degrees and less than 90 degrees, and the interval P2 between adjacent ridge portions of the plurality of second triangular prisms is from the bottom surface of the second triangular prism.
  • H2 the height to the ridge of the second triangular prism
  • a light-emitting device of the present invention has a light guide unit that exhibits a triangular prism, and one of the three side surfaces of the light guide unit is an incident surface on which light is incident, and the other one The light incident on the side surface is a total reflection surface that totally reflects the light, and the remaining one side surface is the light output surface that emits the light that is totally reflected.
  • the incident surface includes a plane including the total reflection surface and a plane including the output surface.
  • a plurality of light sources including a first prism portion including a plurality of first triangular prisms having a ridge portion with a ridge line direction in a direction intersecting with the light source, and a plurality of light sources that allow light to enter the incident surface. Are arranged in the arrangement direction of the first triangular prism.
  • a portion where the first prism portion is not provided exists in a portion of the incident surface that does not face the light source.
  • the emission colors of the plurality of light sources can be different.
  • the optical element contains light scattering particles that multiple-scatter incident light, and the light scattering particles are translucent silicone particles having a particle size of 2 ⁇ m to 9 ⁇ m, which correspond to the scattering coefficient of the light scattering particles.
  • turbidity that is a scattering parameter is ⁇ , it is preferable that ⁇ > 0.01.
  • the base angle ⁇ 1 of the first triangular prism is not less than 20 degrees and not more than 70 degrees, and the interval P1 between adjacent ridge portions of the plurality of first triangular prisms is ridged from the bottom surface of the first triangular prism.
  • the height to the portion is H1
  • the light scattering particles are translucent silicone particles having a particle size of 2 ⁇ m to 9 ⁇ m, and the optical element has ⁇ > when turbidity, which is a scattering parameter corresponding to the scattering coefficient by the light scattering particles, is ⁇ > It is preferable that it is 0.01.
  • a second prism portion including a plurality of second triangular prisms arranged along the arrangement direction of the plurality of first triangular prisms is provided on the emission surface.
  • the base angle ⁇ 2 of the second triangular prism portion is not less than 50 degrees and less than 90 degrees, and the interval P2 between adjacent ridge portions of the plurality of second triangular prisms is from the bottom surface of the second triangular prism.
  • H2 the height to the ridge of the second triangular prism
  • the present invention when a plurality of light sources such as LEDs are used as the light source, it is possible to provide an optical element and a light emitting device capable of making the illuminance and luminance of illumination light more uniform and reducing glare.
  • FIG. 2 is a simplified diagram of the light emitting device according to the first embodiment of the present invention, and is a diagram showing a positional relationship between the light guide and the LED shown in FIG. 1.
  • a light-emitting device similar to the light-emitting device according to the first embodiment of the present invention is configured using a light guide that omits the first prism portion and the light scattering particles from the light guide. It is a figure which shows the luminance distribution of the surface equivalent to an output surface.
  • the light emitting device according to the first embodiment of the present invention which emits light under the same conditions as the light emitting device of the comparative example shown in FIG. 9, and uses the light guide that does not contain light scattering particles, the luminance of the exit surface It is a figure which shows distribution.
  • the light emitting device according to the first embodiment of the present invention which emits light under the same conditions as the light emitting device of the comparative example shown in FIG.
  • FIG. 9 is a view showing a modification of the light emitting device according to the first embodiment of the present invention in a state where a reflecting member that covers the left end surface, the right end surface, the incident surface, and the total reflection surface of the light guide is attached to the light emitting device. is there.
  • FIG. 1 is a perspective view showing a configuration of a light guide 1 which is an optical element according to the first embodiment of the present invention.
  • a light guide 1 (optical element) having a light guide portion 1A, which is a resin molded body made of transparent polymethyl methacrylate (hereinafter abbreviated as “PMMA”), has a planar left end. It has a long triangular prism shape in a direction from the surface 2 toward the planar right end surface 3.
  • the three side surfaces of the light guide section 1 ⁇ / b> A presenting a triangular prism are an incident surface 4 on which light is incident, a total reflection surface 5 that totally reflects incident light, and an output surface 6 that emits the totally reflected light to the outside.
  • the light guide 1 contains the light-scattering particle
  • the incident surface 4 is provided with a first prism portion 7 composed of three first triangular prisms 7A that spread incident light in the longitudinal direction.
  • the first triangular prism 7 ⁇ / b> A has a ridge portion 12 whose ridge line direction is directed in a direction intersecting a plane including the total reflection surface 5 and a plane including the exit surface 6. That is, the first triangular prism 7A has the ridge line direction oriented in a direction perpendicular to the ridge 4A where the incident surface 4 and the total reflection surface 5 intersect and the ridge 4B where the incident surface 4 and the exit surface 6 intersect. It has a ridge 12.
  • the angle ⁇ formed by the incident surface 4 and the total reflection surface 5 is 40 degrees
  • the angle ⁇ formed by the total reflection surface 5 and the output surface 6 is 50 degrees
  • ⁇ is 90 degrees.
  • a plurality of first prism portions 7 are provided at regular intervals along the longitudinal direction of the light guide 1 (the direction parallel to the ridge portions 4A and 4B), and between the first prism portions 7, The first prism portion 7 is not formed on the prism non-formed portion 8.
  • FIG. 2 is a view of the first prism portion 7 as viewed from the exit surface 6 side shown in FIG.
  • the first prism portion 7 has a plurality of first triangular prisms 7A. These first triangular prisms 7A are formed by zigzag irregularities formed by intersecting a plurality of slopes 11 adjacent in a V shape. Each inclined surface 11 extends along the short direction of the light guide 1 (the direction connecting the ridge 4A and the ridge 4B). A ridge line including the vertex of the convex portion is the ridge portion 12.
  • the angle ⁇ 1 formed by the inclined surface 11 and the bottom surface 13 is 45 degrees.
  • the distance P1 between the adjacent ridges 12 is within the range of (2 ⁇ H1 / tan ⁇ 1) ⁇ P ⁇ (10 ⁇ H1 / tan ⁇ 1), where the height from the bottom surface 13 to the ridge 12 is H1.
  • P1 2 ⁇ H1 / tan ⁇ 1
  • the inclined surfaces 11 intersect each other on the concave side.
  • H1 0.25
  • P1 is 0.5 mm.
  • This silicone particle is a light guide provided with a volumetric uniform scattering ability, and includes a large number of spherical particles as scattering fine particles. When light enters the light guide 1, the light is scattered by the scattering fine particles.
  • Mie scattering theory is the solution of Maxwell's electromagnetic equation for the case where spherical particles (scattering fine particles) having a refractive index different from that of the medium exist in a medium (matrix) having a uniform refractive index. .
  • the intensity distribution I ( ⁇ , ⁇ ) depending on the angle of the scattered light scattered by the scattering fine particles corresponding to the light scattering particles is expressed by the following equation (1).
  • ⁇ is a size parameter indicating the optical size of the scattering fine particles, and is an amount corresponding to the radius r of the spherical particles (scattering fine particles) normalized by the wavelength ⁇ of light in the matrix.
  • i 1 and i 2 in the formula (1) are represented by the formula (4).
  • a and b with the subscript ⁇ in the expressions (2) to (4) are expressed by the expression (5).
  • P (cos ⁇ ) with superscript 1 and subscript ⁇ is Legendre's polynomial
  • a and b with subscript ⁇ are first- and second-order Recati-Bessel functions ⁇ * and ⁇ * (where “*” Means the subscript ⁇ ) and its derivative.
  • m is the relative refractive index of the scattering fine particles based on the matrix
  • m nscatter / nmattrix.
  • FIG. 3 is a graph showing the intensity distribution I ( ⁇ , ⁇ ) by a single true spherical particle based on the above equations (1) to (5).
  • FIG. 3 shows an angular distribution I ( ⁇ , ⁇ ) of scattered light intensity when there is a true spherical particle as a scattering fine particle at the position of the origin G and incident light is incident from below.
  • the distance from the origin G to each of the curves S1 to S3 is the scattered light intensity in each scattering angle direction.
  • Curve S1 shows the scattered light intensity when ⁇ is 1.7
  • curve S2 shows the scattered light intensity when ⁇ is 11.5
  • curve S3 shows the scattered light intensity when ⁇ is 69.2. Yes.
  • the scattered light intensity is shown on a logarithmic scale. For this reason, the portion that appears as a slight difference in intensity in FIG. 3 is actually a very large difference.
  • the larger the size parameter ⁇ (the larger the particle size of the true spherical particle when considered at a certain wavelength ⁇ ), the higher the directivity with respect to the upper side (front of the irradiation direction). It can be seen that light is highly scattered. Actually, the angle distribution I ( ⁇ , ⁇ ) of the scattered light intensity is controlled by using the radius r of the scatterer and the relative refractive index m of the medium and the scattered fine particles as parameters if the incident light wavelength ⁇ is fixed. can do. In addition, the light guide 1 has a large forward scattering.
  • I ( ⁇ ) in the equation (6) is the scattering intensity of the true spherical particle having the size parameter ⁇ represented by the equation (1). If light of intensity Io enters the light scattering light guide and passes through the distance y, then the intensity of the light is attenuated to I by scattering, and these relationships are expressed by the following equation (7).
  • ⁇ in the equation (7) is called turbidity and corresponds to the scattering coefficient of the medium, and is proportional to the number N of particles as in the following equation (8).
  • ⁇ s is a scattering cross section.
  • the degree of multiple scattering in the light scattering light guide can be controlled by changing the turbidity ⁇ .
  • the light scattering particles contained in the light guide 1 are translucent silicone particles having an average particle diameter of 2.4 ⁇ m.
  • FIG. 4 is a simplified diagram of the light emitting device 21 according to the first embodiment of the present invention, and is a diagram showing a positional relationship between the light guide 1 and the LEDs 22 shown in FIG.
  • the LED 22 as a light source is a chip type chip that emits white light and has a diameter of 2.4 mm, and its luminous flux is 9 lm.
  • the LED 22 is disposed at a position facing each first prism portion 7. In the present embodiment, for example, they are arranged at intervals of 25 mm, and light is emitted toward the first prism portions 7.
  • FIG. 5 is a diagram showing the simplification of the light path (light path when the light emitted from the LED 22 passes through the light guide 1) L of the light emitting device 21, and is a view seen from the right end face 3 side.
  • the light emitted from the LED 22 passes through the incident surface 4, is totally reflected by the total reflection surface 5, and is emitted from the emission surface 6.
  • FIG. 6 is a diagram showing the state of light refraction when the light emitted from the LED 22 passes through the first prism unit 7 in the light emitting device 21.
  • the light L1 emitted from the LED 22 is incident on the inclined surface 11 of the first prism portion 7 (first triangular prism 7A).
  • the light L1 incident on the slope 11 on the left end surface 2 side of the ridge 12 is refracted on the right end surface 3 side, and the light L1 incident on the slope 11 on the right end surface 3 of the ridge 12 is the left end. Refracts to the surface 2 side.
  • the light emitted from the LED 22 and incident on the first prism portion 7 as a whole is compared with the case where the light is incident on a plane where the first prism portion 7 is not formed. Is diverged to the side.
  • the inclined surface 11 is not inclined with respect to the short direction of the incident surface 4. Therefore, the incident light L ⁇ b> 1 is difficult to diverge in the short direction of the light guide 1. Further, the light L1 incident on the light guide 1 is multiple-scattered by the light scattering particles.
  • FIG. 7 is a perspective view showing a configuration of a light guide 31 which is an optical element according to the second embodiment of the present invention.
  • the difference between the light guide 31 and the light guide 1 is that the second prism portion 32 that refracts the emitted light in the longitudinal direction of the light guide 31 and brings the emission direction closer to the direction orthogonal to the emission surface is emitted.
  • This is a point provided on the entire surface 6.
  • the light emitting device 41 described later using the light guide 31 and the light emitting device 21 have no structural difference except for this point. Therefore, members or elements that are common to the light guide 1 and the light guide 31, and members or elements that are common to the light emitting device 21 and the light emitting device 41 are denoted by the same reference numerals and described below. Detailed description is omitted.
  • FIG. 8 is a view of the second prism portion 32 viewed from the incident surface 4 side shown in FIG. 7 in the light emitting device 41.
  • the second prism portion 32 has a plurality of second triangular prisms 32A. These second triangular prisms 32A are formed by zigzag irregularities formed by intersecting a plurality of second inclined surfaces 42 adjacent to each other in a V shape. Each second inclined surface 42 extends along the short direction of the light guide 31 (the direction connecting the ridge 4A and the ridge 4B). The ridge line including the vertex of the second convex portion is the second ridge portion 43.
  • the angle ⁇ 2 formed by the second inclined surface 42 and the second bottom surface 44 is 80 degrees.
  • the interval P2 between the adjacent second ridges 43 is (2 ⁇ H2 / tan ⁇ 2) ⁇ P2 ⁇ (20, where the height from the second bottom surface 44 to the second ridge 43 is H2.
  • XH2 / tan ⁇ 2) is set to be within a range.
  • P2 2 ⁇ H2 / tan ⁇ 2
  • the second slope 42 intersects on the concave side.
  • H2 0.3 mm and P2 is 0.2 mm.
  • FIG. 8 shows an optical path of the light L2 emitted from the emission surface 6.
  • the light L2 incident on the second inclined surface 42 on the right end surface 3 side with respect to the ridge 43 is refracted toward the right end surface 3 and the second inclined surface 42 on the left end surface 2 with respect to the ridge 43.
  • the light L2 incident on is refracted toward the left end face 2 side. That is, the light exiting from the exit surface 6 is refracted so that the exit direction is closer to the direction orthogonal to the exit surface 6 as a whole compared to when exiting from a plane on which the second prism portion 32 is not formed. To do.
  • the light guides 1, 31 and the light emitting devices 21, 41 using the light guides 1, 31 have a plurality of first light that can diverge (expand) incident light on the incident surface 4 of the light guides 1, 31 in the longitudinal direction.
  • a first prism portion 7 composed of a triangular prism 7A is provided. Therefore, the light guides 1 and 31 and the light emitting devices 21 and 41 using the light guides 1 and 31 can make the illumination light illuminance more uniform and reduce glare even when a plurality of light sources such as the LEDs 22 are used as the light source. .
  • FIG. 9 shows a surface corresponding to the emission surface 6 when a light-emitting device similar to the light-emitting device 21 is configured by using a light-guiding body in which the prism portion 7 and the light scattering particles are omitted from the light-guiding body 1 as a comparative example. It is a figure which shows the luminance distribution in. In the light guide of the comparative example, the portion corresponding to the first prism portion 7 is planar. The diagram on the left represents the luminance distribution on the surface corresponding to the exit surface 6 by the color shading, and shows that the luminance decreases as the color approaches black and increases as the color approaches white.
  • the figure on the right side is a graph showing the luminance distribution of the middle line in the short direction of the surface corresponding to the exit surface 6 of the light guide of the comparative example. It can be seen that the light emitting device of the comparative example has light emitting portions in the form of stripes arranged in the longitudinal direction of the surface corresponding to the emission surface 6, and the difference in luminance between the dark portion and the bright portion is about 12000 cd / m 2 .
  • FIG. 10 is a light-emitting device 21 according to an embodiment of the present invention that emits light under the same conditions as the light-emitting device of the comparative example, and uses a light guide that does not contain light scattering particles.
  • FIG. The diagram on the left shows the luminance distribution on the exit surface 6 with shades of color
  • the diagram on the right is a graph showing the brightness distribution of the middle line of the exit surface 6 in the short direction.
  • the light emitting device 21 has light emitting portions in the longitudinal direction of the emission surface 6 in stripes arranged more finely than the light emitting device of the comparative example.
  • the difference in luminance between the dark part and the bright part is about 5000 cd / m 2 . This shows that the light-emitting device 21 can irradiate light more uniformly than the light-emitting device of the comparative example.
  • the light guides 1 and 31 are such that the first triangular prism 7A constituting the first prism unit 7 has an angle ⁇ 1 formed by the inclined surface 11 and the bottom surface 13 of 45 degrees of 20 degrees or more and 70 degrees or less.
  • the light guides 1 and 31 contain light scattering particles that multiple-scatter the emitted light, and the light scattering particles are translucent silicone particles having a particle diameter of 2 ⁇ m to 9 ⁇ m. By setting it as this particle size range, the forward scattering of the incident light of the light guide 1 can be increased within an appropriate range.
  • turbidity which is a scattering parameter corresponding to a scattering coefficient by light scattering particles
  • FIG. 11 shows a light emitting device 21 according to an embodiment of the present invention that emits light under the same conditions as the light emitting device of the comparative example, and uses a light guide that does not contain light scattering particles 40 mm above the emission surface 6.
  • the diagram on the left represents the illuminance distribution in shades of color as in FIG. 9, and the diagram on the right shows the longitudinal direction of the light guide 1 at the center of the irradiation area of the light irradiated from the exit surface 6.
  • FIG. 11 shows a light emitting device 21 according to an embodiment of the present invention that emits light under the same conditions as the light emitting device of the comparative example, and uses a light guide that does not contain light scattering particles 40 mm above the emission surface 6.
  • the diagram on the left represents the illuminance distribution in shades of color as in
  • FIG. 12 is a diagram showing the illuminance distribution of a portion 40 mm above the exit surface 6 of the light emitting device 21 according to the embodiment of the present invention that emits light under the same conditions as the light emitting device of the comparative example.
  • It is a graph which shows the illuminance distribution of the direction along a direction. The illuminance is evaluated at a position 40 mm away from the emission surface 6.
  • the light-emitting body 1 contains light scattering particles shown in FIG.
  • the illuminated portion is not striped and is uniform.
  • the light guide 31 is composed of a plurality of second triangular prisms 32A made of a plurality of second triangular prisms 32A that refract the light emitted to the emission surface 6 in the longitudinal direction and refract the emission direction so as to approach the direction orthogonal to the emission surface 6.
  • Two prism portions 32 are provided. Therefore, it is possible to prevent the light emission direction from extending in the longitudinal direction from the emission surface 6, and the light emission direction of the light emitting device 41 can be brought closer to the direction orthogonal to the emission surface 6.
  • FIG. 13 is a diagram showing a luminance distribution on the exit surface 6 of the light emitting device 21 according to the embodiment of the present invention that emits light under the same conditions as the light emitting device of the comparative example.
  • the diagram on the left shows the luminance distribution in shades of color
  • the diagram on the right is a graph showing the luminance distribution of the middle line in the short direction of the surface corresponding to the exit surface 6 of the light guide of the comparative example. is there.
  • FIG. 14 is a diagram showing a luminance distribution of the emission surface 6 of the light emitting device 41 according to the embodiment of the present invention that emits light under the same conditions as the light emitting device of the comparative example. As shown in FIG.
  • the luminance of the bright portion is about 11000 cd / m 2 , which indicates that the luminance is higher than that of the light emitting device 21.
  • the second triangular prism 32A constituting the second prism portion 32 has an angle ⁇ 2 formed by the second inclined surface 42 and the second bottom surface 44 of 80 degrees within a range of 50 degrees or more and less than 90 degrees.
  • the interval P2 between the adjacent ridges 43 is H2 from the bottom 44 to the ridge 43, It is set to be in the range of (2 ⁇ H2 / tan ⁇ 2) ⁇ P2 ⁇ (20 ⁇ H2 / tan ⁇ 2).
  • P2 2 ⁇ H2 / tan ⁇ 2
  • the inclined surfaces 42 intersect with each other on the concave side.
  • H2 0.3 mm and P2 is 0.2 mm.
  • the reason why the angle ⁇ 2 is set to 50 degrees or more is to make it easier to refract the emitted light in the direction orthogonal to the emission surface 6 and to make the luminance of the emission surface 6 more uniform.
  • the reason why the angle ⁇ 2 is less than 90 degrees and the reason why (2 ⁇ H / tan ⁇ 2) ⁇ P2 are due to physical restrictions. If P2 ⁇ (20 ⁇ H2 / tan ⁇ 2), the interval between the adjacent second triangular prisms 32 is widened, and a plane portion is formed between the adjacent second triangular prisms 32. Further, it is possible to suppress the emission direction of the light emitted from the emission surface 6 from spreading in the longitudinal direction, and the light emission direction of the light emitting device 41 can be brought close to the direction orthogonal to the emission surface 6.
  • the LEDs 22 are arranged at a plurality of equal intervals in the longitudinal direction of the light guides 1, 31, and the prism-unformed portion 8 in which the first prism portion 7 is not provided in the portion of the incident surface 4 that does not face the LED 22. Is present.
  • a part of the light that spreads in the lateral direction and cannot enter the first prism 7 is incident on the light guides 1 and 31 in the prism non-formation portion 8.
  • Light that spreads in the lateral direction and enters the prism-unformed portion 8 has already spread in the longitudinal direction of the light guides 1 and 31, and therefore does not need to be further refracted by the first prism 7. Therefore, the formation place of the 1st prism 7 can be reduced, and the process at the time of manufacture, etc. can be simplified.
  • the angle ⁇ formed between the incident surface 4 and the total reflection surface 5 of the light guides 1 and 31 is 40 degrees, and the angle ⁇ formed between the total reflection surface 5 and the output surface 6 is 50 degrees, and the output surface 6 and the incident surface 6 are incident.
  • the angle ⁇ made with the surface 4 is 90 degrees. That is, the width dimension of the exit surface 6 is made smaller than the width dimension of the entrance surface 4. Therefore, the light guides 1 and 31 have an advantageous shape when the width dimension of the emission surface 6 must be reduced due to the installation environment of the light emitting devices 21 and 41.
  • the light guides 1 and 31 have triangular prism side surfaces that are long in the direction from the planar left end surface 2 to the right end surface 3, and the three side surfaces are respectively an incident surface 4 on which light is incident and incident light. Is a total reflection surface 5 that totally reflects light, and an emission surface 6 that emits the totally reflected light to the outside.
  • the incident surface 4 includes a first triangular prism 7A that spreads incident light in the longitudinal direction.
  • the prism portion 7 is provided, and the first triangular prism 7A is formed by a zigzag uneven portion (saw-toothed prism portion) formed by crossing a plurality of slopes 11 adjacent to each other in a V shape.
  • the angle ⁇ 1 formed by the inclined surface 11 and the bottom surface 13 is 20 degrees or more.
  • the interval P1 between the adjacent ridges 12 is 70 degrees or less. If from the bottom surface 13 to the ridge 12 height was H1, a (2 ⁇ H1 / tan ⁇ 1) ⁇ P1 ⁇ (10 ⁇ H1 / tan ⁇ 1).
  • the left end surface 2, the right end surface 3, the entrance surface 4 and the exit surface 6 do not have to be flat, and may be, for example, rounded convex shapes.
  • the angle ⁇ 1 formed by the slope 11 and the bottom surface 13 is set to 20 degrees or more and 70 degrees or less, and the interval P1 between the ridge portions 12 of the first triangular prism 7A is a height from the bottom surface 13 to the ridge portion 12.
  • H1 is H1
  • either or both of (2 ⁇ H1 / tan ⁇ 1) ⁇ P1 ⁇ (10 ⁇ H1 / tan ⁇ 1) may not be adopted.
  • the light guides 1 and 31 contain light scattering particles that multiple-scatter incident light.
  • the light scattering particles have a light-transmitting property with a particle diameter of 2.4 ⁇ m within a range of 2 ⁇ m to 9 ⁇ m.
  • turbidity which is a silicone particle and is a scattering parameter corresponding to the scattering coefficient by the light scattering particles
  • the light scattering particles may not be contained in the light guides 1 and 31. Even if it is included, any one of the two of the light scattering particles having a particle diameter of 2 ⁇ m to 9 ⁇ m, a translucent silicone particle, and ⁇ > 0.01. Or not all.
  • the light guide 31 refracts outgoing light on the outgoing surface 6 in the longitudinal direction, and a second prism composed of a plurality of second triangular prisms 32A that brings the outgoing direction closer to a direction orthogonal to the outgoing surface.
  • a portion 32 is provided.
  • the second prism portion 32 may not be provided like the light guide 1.
  • the light guide 31 has a zigzag uneven portion (sawtooth shape) formed by intersecting a plurality of second inclined surfaces 42 adjacent to each other in a V shape. And a ridge line including the apex of the second convex portion as a ridge portion 43, and a surface including a portion where the inclined surface 42 intersects on the second concave portion side is a second bottom surface of the second prism. 44, the angle ⁇ 2 formed by the second inclined surface 42 and the second bottom surface 44 is not less than 50 degrees and less than 90 degrees, and the interval P2 between the adjacent second ridges 43 is the second bottom surface.
  • the angle ⁇ 2 formed by the second inclined surface 42 and the second bottom surface 44 is set to 50 degrees or more and less than 90 degrees, and (2 ⁇ H2 / tan ⁇ 2) ⁇ P2 ⁇ (20 ⁇ H2 / tan ⁇ 2). Either or both of these may not be adopted.
  • the light emitting devices 21 and 41 have triangular prism side surfaces extending in a direction from the planar left end surface 2 to the planar right end surface 3, and the three side surfaces are incident surfaces 4 on which light is incident.
  • the incident surface 4 has a prism portion 7 composed of a plurality of prisms that spread the incident light in the longitudinal direction. Are provided, and an LED 22 that emits light toward the incident surface 6 is disposed at a position facing the prism portion 7 on the incident surface 4 side.
  • the left end surface 2 and the right end surface 3 do not have to be flat, and may be, for example, rounded convex shapes.
  • another light source for example, discharge light (xenon lamp, mercury lamp) or laser with high light density may be used.
  • a plurality of LEDs 22 are arranged at equal intervals in the longitudinal direction of the light guides 1 and 31.
  • the LEDs 22 do not have to be arranged at equal intervals and may be unevenly distributed.
  • the first prism portion 7 may be formed over the entire incident surface 4 without the prism-unformed portion 8 being present.
  • the emission color of the plurality of LEDs 22 is white, the emission color of the plurality of LEDs 22 may be different. Then, the light guides 1 and 31 may be mixed in color, and the mixed color light may be emitted from the emission surface 6. Further, the LED 22 is not limited to a chip type but can be a discrete type LED or the like.
  • the light guides 1 and 31 are made of PMMA, but other acrylic ester or methacrylic ester polymer, which is an acrylic resin that is a highly transparent amorphous resin, Other light-transmitting resins such as polystyrene and polycarbonate, and those made of glass can be used.
  • FIG. 15 is a modification of the light emitting device 21 according to the first embodiment of the present invention, and shows a reflecting member 51 that covers the left end surface 2, the right end surface 3, the incident surface 4, and the total reflection surface 5 of the light guide 1. It is a figure which shows the state attached to the light-emitting device 21.
  • the reflecting member 51 includes a material having a high light reflectivity, for example, a mirror surface material, a metal material, a white ceramic material, and the like, and reflects light leaking from other than the exit surface 6 of the light guide 1 to thereby reflect the inside of the light guide 1. Play the role of returning to.
  • the reflecting member 51 has a hole 52 for fitting and fixing the LED 22. For this reason, the hole part 52 hold
  • the hole 52 may not be provided, and the LED 22 may be fixed to the inner surface of the reflecting member 51, or the reflecting member 51 may not fix the LED 22.
  • the reflecting member 51 may be attached to the light emitting device 41. Further, the reflecting member 51 covers the entire left end surface 2, right end surface 3, incident surface 4 and total reflection surface 5 of the light guide 1, but covers any one, two or three of these.
  • the left end surface 2, the right end surface 3, the incident surface 4, and the total reflection surface 5 may be partially covered.
  • the reflecting member 51 increases the light reflectance of the portion facing the left end surface 2 and the right end surface 3 in order to suppress the light spread by the prism portion 7 from being emitted from the left end surface 2 and the right end surface 3. Also good.

Abstract

Disclosed are an optical element and a light-emitting device both for making the illuminant of illuminating light more uniform and reducing the glare when a plurality of light sources such as LEDs are used as light sources. The light-emitting device (21) is provided with a light guide (1) which comprises a light guide section (1A) having a shape of a triangular prism. Of the three side surfaces of the light guide section (1A), a side surface is made to serve as an entrance surface (4) through which light enters, another side surface is made to serve as a total reflection surface (5) which totally reflects the light having entered, and the other side surface is made to serve as an exit surface (6) from which the totally reflected light is allowed to exit outside. On the entrance surface (4), provided is a first prism section (7) composed of a plurality of first triangular prisms (7A) having edge sections (12) the edge direction of which crosses the plane including the total reflection surface (5) and the plane including the exit surface (6). A plurality of light sources (22) for allowing light to enter through the entrance surface (4) are arranged in the direction in which the first triangular prisms (7A) are arranged.

Description

光学素子および発光装置Optical element and light emitting device
　本発明は、光学素子および発光装置に関する。 The present invention relates to an optical element and a light emitting device.
　ＬＥＤ（Light Emitting Diode）を光源に用いた発光装置としては、以下のものが提案されている。すなわち、複数のＬＥＤを所定間隔に並べ、そのＬＥＤの並ぶ方向に沿って長尺な透明体をＬＥＤに近接させて配置し、その透明体においてＬＥＤの光が通過する光照射面に、ＬＥＤの光を散乱させる光散乱層が塗布されたものである。この発光装置は、ＬＥＤの光を均一に照射することが可能であるとされている（特許文献１参照）。 The following are proposed as light emitting devices using LEDs (Light Emitting Diodes) as light sources. That is, a plurality of LEDs are arranged at a predetermined interval, and a long transparent body is arranged close to the LEDs along the direction in which the LEDs are arranged. A light scattering layer for scattering light is applied. This light-emitting device is supposed to be able to uniformly irradiate light from an LED (see Patent Document 1).
特開２００９－３２５６３号公報JP 2009-32563 A
　しかしながら、特許文献１に記載されている発光装置によっても、光散乱層の散乱能のみだけでは光を均一に照射するのが不十分なことがある。すると光の照射密度の高い部分ではグレアが発生する。また、この発光装置の製造の際には、光散乱層の塗布工程を要し、煩雑である。 However, even with the light-emitting device described in Patent Document 1, it may be insufficient to irradiate light uniformly only with the scattering ability of the light scattering layer. Then, glare occurs in a portion where the light irradiation density is high. Further, when manufacturing the light emitting device, a light scattering layer coating process is required, which is complicated.
　そこで、本発明の目的は、光源としてＬＥＤ等の光源を複数用いた場合に、照明光の照度をより均一にし、グレアを低減することが可能な光学素子および発光装置を提供することである。 Therefore, an object of the present invention is to provide an optical element and a light-emitting device that can make the illuminance of illumination light more uniform and reduce glare when a plurality of light sources such as LEDs are used as the light source.
　上記目的を達成するため、本発明の光学素子は、三角柱を呈する導光部を有し、導光部の３つの側面のうち、１つの側面を光が入射する入射面とし、他の１つの側面を入射した光を全反射する全反射面とし、残りの１つの側面を全反射した光を外部へ出射する出射面とし、入射面には、全反射面を含む平面と出射面を含む平面とに交差する方向に稜線方向を向けた稜部を有する複数の第１の三角プリズムからなる第１のプリズム部が設けられている。 In order to achieve the above object, an optical element of the present invention has a light guide part that exhibits a triangular prism, and one of the three side surfaces of the light guide part is an incident surface on which light is incident, and the other one The light incident on the side surface is a total reflection surface that totally reflects the light, and the remaining one side surface is the light output surface that emits the light that is totally reflected. The incident surface includes a plane including the total reflection surface and a plane including the output surface. And a first prism portion including a plurality of first triangular prisms having a ridge portion with a ridge line direction in a direction intersecting with.
　ここで、第１の三角プリズムの底角θ１が２０度以上７０度以下であり、かつ、複数の第１の三角プリズムの隣り合う稜部間の間隔Ｐ１が、第１の三角プリズムの底面から稜部までの高さをＨ１とした場合、（２×Ｈ１／ｔａｎθ１）≦Ｐ１＜（１０×Ｈ１／ｔａｎθ１）であることが好ましい。 Here, the base angle θ1 of the first triangular prism is not less than 20 degrees and not more than 70 degrees, and the interval P1 between adjacent ridges of the plurality of first triangular prisms is from the bottom surface of the first triangular prism. When the height to the ridge is H1, it is preferable that (2 × H1 / tan θ1) ≦ P1 <(10 × H1 / tan θ1).
　また、入射した光を多重散乱させる光散乱粒子を含有し、光散乱粒子は、粒径が２μｍ～９μｍの透光性のシリコーン粒子であり、光散乱粒子による散乱係数に相当する散乱パラメータである濁度をτとした場合、τ＞０．０１であることが好ましい。 Further, it contains light scattering particles for multiply scattering incident light. The light scattering particles are translucent silicone particles having a particle size of 2 μm to 9 μm, and have a scattering parameter corresponding to a scattering coefficient by the light scattering particles. When turbidity is τ, it is preferable that τ> 0.01.
　また、出射面には複数の第１の三角プリズムの配置方向に沿って配置される複数の第２の三角プリズムからなる第２のプリズム部が設けられていることが好ましい。 Further, it is preferable that a second prism portion including a plurality of second triangular prisms arranged along the arrangement direction of the plurality of first triangular prisms is provided on the emission surface.
　また、第２の三角プリズム部の底角θ２が５０度以上９０度未満であり、かつ、複数の第２の三角プリズムの隣り合う稜部間の間隔Ｐ２が、第２の三角プリズムの底面から第２の三角プリズムの稜部までの高さをＨ２とした場合、（２×Ｈ２／ｔａｎθ２）≦Ｐ２＜（２０×Ｈ２／ｔａｎθ２）であることが好ましい。 Further, the base angle θ2 of the second triangular prism portion is not less than 50 degrees and less than 90 degrees, and the interval P2 between adjacent ridge portions of the plurality of second triangular prisms is from the bottom surface of the second triangular prism. When the height to the ridge of the second triangular prism is H2, it is preferable that (2 × H2 / tan θ2) ≦ P2 <(20 × H2 / tan θ2).
　上記目的を達成するため、本発明の発光装置は、三角柱を呈する導光部を有し、導光部の３つの側面のうち、１つの側面を光が入射する入射面とし、他の１つの側面を入射した光を全反射する全反射面とし、残りの１つの側面を全反射した光を外部へ出射する出射面とし、入射面には、全反射面を含む平面と出射面を含む平面とに交差する方向に稜線方向を向けた稜部を有する複数の第１の三角プリズムからなる第１のプリズム部が設けられる光学素子を備え、入射面に光を入射させる複数の光源が、複数の第１の三角プリズムの配置方向に配置されている。 In order to achieve the above object, a light-emitting device of the present invention has a light guide unit that exhibits a triangular prism, and one of the three side surfaces of the light guide unit is an incident surface on which light is incident, and the other one The light incident on the side surface is a total reflection surface that totally reflects the light, and the remaining one side surface is the light output surface that emits the light that is totally reflected. The incident surface includes a plane including the total reflection surface and a plane including the output surface. A plurality of light sources including a first prism portion including a plurality of first triangular prisms having a ridge portion with a ridge line direction in a direction intersecting with the light source, and a plurality of light sources that allow light to enter the incident surface. Are arranged in the arrangement direction of the first triangular prism.
　ここで、入射面の光源と対向しない部分には、第１のプリズム部が設けられない部分が存在することが好ましい。 Here, it is preferable that a portion where the first prism portion is not provided exists in a portion of the incident surface that does not face the light source.
　また、複数の光源の発光色が異なることとすることができる。 Also, the emission colors of the plurality of light sources can be different.
　また、光学素子は、入射した光を多重散乱させる光散乱粒子を含有し、光散乱粒子は、粒径が２μｍ～９μｍの透光性のシリコーン粒子であり、光散乱粒子による散乱係数に相当する散乱パラメータである濁度をτとした場合、τ＞０．０１であることが好ましい。 The optical element contains light scattering particles that multiple-scatter incident light, and the light scattering particles are translucent silicone particles having a particle size of 2 μm to 9 μm, which correspond to the scattering coefficient of the light scattering particles. When turbidity that is a scattering parameter is τ, it is preferable that τ> 0.01.
　また、第１の三角プリズムの底角θ１が２０度以上７０度以下であり、かつ、複数の第１の三角プリズムの隣り合う稜部間の間隔Ｐ１が、第１の三角プリズムの底面から稜部までの高さをＨ１とした場合、（２×Ｈ１／ｔａｎθ１）≦Ｐ１＜（１０×Ｈ１／ｔａｎθ１）であることが好ましい。 In addition, the base angle θ1 of the first triangular prism is not less than 20 degrees and not more than 70 degrees, and the interval P1 between adjacent ridge portions of the plurality of first triangular prisms is ridged from the bottom surface of the first triangular prism. When the height to the portion is H1, it is preferable that (2 × H1 / tan θ1) ≦ P1 <(10 × H1 / tan θ1).
　また、光散乱粒子は、粒径が２μｍ～９μｍの透光性のシリコーン粒子であり、光学素子は、光散乱粒子による散乱係数に相当する散乱パラメータである濁度をτとした場合、τ＞０．０１であることが好ましい。 Further, the light scattering particles are translucent silicone particles having a particle size of 2 μm to 9 μm, and the optical element has τ> when turbidity, which is a scattering parameter corresponding to the scattering coefficient by the light scattering particles, is τ> It is preferable that it is 0.01.
　また、出射面には前記複数の第１の三角プリズムの配置方向に沿って配置される複数の第２の三角プリズムからなる第２のプリズム部が設けられていることが好ましい。 Further, it is preferable that a second prism portion including a plurality of second triangular prisms arranged along the arrangement direction of the plurality of first triangular prisms is provided on the emission surface.
　また、第２の三角プリズム部の底角θ２が５０度以上９０度未満であり、かつ、複数の第２の三角プリズムの隣り合う稜部間の間隔Ｐ２が、第２の三角プリズムの底面から第２の三角プリズムの稜部までの高さをＨ２とした場合、（２×Ｈ２／ｔａｎθ２）≦Ｐ２＜（２０×Ｈ２／ｔａｎθ２）であることが好ましい。 Further, the base angle θ2 of the second triangular prism portion is not less than 50 degrees and less than 90 degrees, and the interval P2 between adjacent ridge portions of the plurality of second triangular prisms is from the bottom surface of the second triangular prism. When the height to the ridge of the second triangular prism is H2, it is preferable that (2 × H2 / tan θ2) ≦ P2 <(20 × H2 / tan θ2).
　本発明では、光源としてＬＥＤ等の光源を複数用いた場合に、照明光の照度や輝度をより均一にし、グレアを低減することが可能な光学素子および発光装置を提供することができる。 In the present invention, when a plurality of light sources such as LEDs are used as the light source, it is possible to provide an optical element and a light emitting device capable of making the illuminance and luminance of illumination light more uniform and reducing glare.
本発明の第１の実施の形態に係る光学素子である導光体の構成を示す斜視図である。It is a perspective view which shows the structure of the light guide which is an optical element which concerns on the 1st Embodiment of this invention. 図１に示す出射面の側から第１のプリズム部を見た部分拡大図である。It is the elements on larger scale which looked at the 1st prism part from the outgoing radiation side shown in FIG. 図１および図２に示す導光体中の光散乱粒子となるシリコーン粒子の散乱原理を示す図で、単一真球粒子による散乱光強度の角度分布（Α、Θ）を示すグラフである。It is a figure which shows the scattering principle of the silicone particle | grains used as the light-scattering particle | grains in the light guide shown in FIG. 1 and FIG. 2, and is a graph which shows angle distribution (Α, Θ) of the scattered light intensity by a single true spherical particle. 本発明の第１の実施の形態に係る発光装置の簡略図であり、図１に示した導光体とＬＥＤとの位置関係を示す図である。FIG. 2 is a simplified diagram of the light emitting device according to the first embodiment of the present invention, and is a diagram showing a positional relationship between the light guide and the LED shown in FIG. 1. 本発明の第１の実施の形態に係る発光装置の光路の簡略図であって、右端面から見た図である。It is the simplified view of the optical path of the light-emitting device which concerns on the 1st Embodiment of this invention, Comprising: It is the figure seen from the right end surface. 発光装置において、ＬＥＤから発せられた光が第１のプリズム部を透過する際の光の屈折の状況を示す図である。In a light-emitting device, it is a figure which shows the refraction | bending state of the light at the time of the light emitted from LED transmitting the 1st prism part. 本発明の第２の実施の形態に係る光学光学素子である導光体の構成を示す斜視図である。It is a perspective view which shows the structure of the light guide which is an optical optical element which concerns on the 2nd Embodiment of this invention. 図７に示す入射面の側から第２のプリズム部を見た部分拡大図である。It is the elements on larger scale which looked at the 2nd prism part from the entrance plane side shown in FIG. 比較例として、導光体から第１のプリズム部及び光散乱粒子を省略した導光体を用いて、本発明の第１の実施の形態に係る発光装置と同様の発光装置を構成した場合の、出射面に相当する面の輝度分布を示す図である。As a comparative example, when a light-emitting device similar to the light-emitting device according to the first embodiment of the present invention is configured using a light guide that omits the first prism portion and the light scattering particles from the light guide. It is a figure which shows the luminance distribution of the surface equivalent to an output surface. 図９に示す比較例の発光装置と同条件で発光させた本発明の第１の実施の形態に係る発光装置であって、光散乱粒子を含有させない導光体を用いたものの出射面の輝度分布を示す図である。The light emitting device according to the first embodiment of the present invention, which emits light under the same conditions as the light emitting device of the comparative example shown in FIG. 9, and uses the light guide that does not contain light scattering particles, the luminance of the exit surface It is a figure which shows distribution. 図９に示す比較例の発光装置と同条件で発光させた本発明の第１の実施の形態に係る発光装置であって、光散乱粒子を含有させない導光体を用いたものの出射面から４０ｍｍ上方に離れた部分の照度分布を示す図である。The light emitting device according to the first embodiment of the present invention, which emits light under the same conditions as the light emitting device of the comparative example shown in FIG. 9, using a light guide that does not contain light scattering particles, is 40 mm from the emission surface. It is a figure which shows the illumination intensity distribution of the part away upwards. 図９に示す比較例の発光装置と同条件で発光させた本発明の第１の実施の形態に係る発光装置の出射面から４０ｍｍ上方に離れた部分の照度分布を示す図である。It is a figure which shows the illuminance distribution of the part 40 mm away from the output surface of the light-emitting device based on the 1st Embodiment of this invention light-emitted on the same conditions as the light-emitting device of the comparative example shown in FIG. 図９に示す比較例の発光装置と同条件で発光させた本発明の第１の実施の形態に係る発光装置の出射面の輝度分布を示す図である。It is a figure which shows the luminance distribution of the output surface of the light-emitting device which concerns on the 1st Embodiment of this invention light-emitted on the same conditions as the light-emitting device of the comparative example shown in FIG. 図９に示す比較例の発光装置と同条件で発光させた本発明の第２の実施の形態に係る発光装置の出射面の輝度分布を示す図である。It is a figure which shows the luminance distribution of the output surface of the light-emitting device based on the 2nd Embodiment of this invention light-emitted on the same conditions as the light-emitting device of the comparative example shown in FIG. 本発明の第１の実施の形態に係る発光装置の変形例で、導光体の左端面、右端面、入射面および全反射面を覆う反射部材を、発光装置に取り付けた状態を示す図である。FIG. 9 is a view showing a modification of the light emitting device according to the first embodiment of the present invention in a state where a reflecting member that covers the left end surface, the right end surface, the incident surface, and the total reflection surface of the light guide is attached to the light emitting device. is there.
　以下、本発明の実施の形態に係る光学素子および発光装置の構成、ならびにそれらの作用について、図面を参照しながら説明する。 Hereinafter, the configuration of the optical element and the light-emitting device according to the embodiment of the present invention and the operation thereof will be described with reference to the drawings.
（第１の実施の形態の光学素子の構成）
　図１は、本発明の第１の実施の形態に係る光学素子である導光体１の構成を示す斜視図である。 (Configuration of Optical Element of First Embodiment)
FIG. 1 is a perspective view showing a configuration of a light guide 1 which is an optical element according to the first embodiment of the present invention.
　図１に示すように、透明のポリメチルメタクリレート（以下、「ＰＭＭＡ」と略記する。）からなる樹脂成形体である導光部１Ａを有する導光体１（光学素子）は、平面状の左端面２から平面状の右端面３に向かう方向に長尺な三角柱状を呈している。三角柱を呈する導光部１Ａの３つの側面は、それぞれ、光が入射する入射面４、入射した光を全反射する全反射面５、全反射した光を外部へ出射する出射面６である。そして、導光体１は、入射した光を多重散乱させる光散乱粒子を含有している。そして、入射面４には入射する光を長尺方向に広げる３つの第１の三角プリズム７Ａからなる第１のプリズム部７が設けられている。第１の三角プリズム７Ａは、全反射面５を含む平面と出射面６を含む平面とに交差する方向に稜線方向を向けた稜部１２を有している。すなわち、第１の三角プリズム７Ａは、入射面４と全反射面５とが交差する稜部４Ａおよび入射面４と出射面６とが交差する稜部４Ｂに直交する方向に稜線方向を向けた稜部１２を有する。ここで、入射面４と全反射面５とのなす角αは、４０度、全反射面５と出射面６とのなす角βは、５０度、出射面６と入射面４とのなす角γは、９０度とされている。第１のプリズム部７は、導光体１の長尺方向（稜部４Ａおよび稜部４Ｂに平行な方向）に沿って一定間隔に複数設けられ、各第１のプリズム部７の間は、第１のプリズム部７が形成されていないプリズム未形成部８となっている。 As shown in FIG. 1, a light guide 1 (optical element) having a light guide portion 1A, which is a resin molded body made of transparent polymethyl methacrylate (hereinafter abbreviated as “PMMA”), has a planar left end. It has a long triangular prism shape in a direction from the surface 2 toward the planar right end surface 3. The three side surfaces of the light guide section 1 </ b> A presenting a triangular prism are an incident surface 4 on which light is incident, a total reflection surface 5 that totally reflects incident light, and an output surface 6 that emits the totally reflected light to the outside. And the light guide 1 contains the light-scattering particle | grains which carry out multiple scattering of the incident light. The incident surface 4 is provided with a first prism portion 7 composed of three first triangular prisms 7A that spread incident light in the longitudinal direction. The first triangular prism 7 </ b> A has a ridge portion 12 whose ridge line direction is directed in a direction intersecting a plane including the total reflection surface 5 and a plane including the exit surface 6. That is, the first triangular prism 7A has the ridge line direction oriented in a direction perpendicular to the ridge 4A where the incident surface 4 and the total reflection surface 5 intersect and the ridge 4B where the incident surface 4 and the exit surface 6 intersect. It has a ridge 12. Here, the angle α formed by the incident surface 4 and the total reflection surface 5 is 40 degrees, the angle β formed by the total reflection surface 5 and the output surface 6 is 50 degrees, and the angle formed by the output surface 6 and the input surface 4. γ is 90 degrees. A plurality of first prism portions 7 are provided at regular intervals along the longitudinal direction of the light guide 1 (the direction parallel to the ridge portions 4A and 4B), and between the first prism portions 7, The first prism portion 7 is not formed on the prism non-formed portion 8.
　図２は、図１に示す出射面６の側から第１のプリズム部７を見た図である。第１のプリズム部７は、複数の第１の三角プリズム７Ａを有している。これらの第１の三角プリズム７Ａは、Ｖ字状に隣接する複数の斜面１１が交差して形成されるジクザグ状の凹凸部により形成されている。そして、各斜面１１は、導光体１の短尺方向（稜部４Ａと稜部４Ｂを結ぶ方向）に沿って伸びている。凸部の頂点を含む稜線が稜部１２である。凹部側において斜面１１が交差する部分を含む面を第１のプリズム７の底面１３としたとき、斜面１１と底面１３とのなす角度θ１が４５度である。そして、隣り合う稜部１２間の間隔Ｐ１は、底面１３から稜部１２までの高さをＨ１とした場合、（２×Ｈ１／ｔａｎθ１）≦Ｐ＜（１０×Ｈ１／ｔａｎθ１）の範囲内となるように設定する。本実施の形態では、Ｐ１＝２×Ｈ１／ｔａｎθ１とされ、凹部側において斜面１１が交差するように構成されている。具体的には、たとえば、Ｈ１＝０．２５とし、Ｐ１が０．５ｍｍとされている。 FIG. 2 is a view of the first prism portion 7 as viewed from the exit surface 6 side shown in FIG. The first prism portion 7 has a plurality of first triangular prisms 7A. These first triangular prisms 7A are formed by zigzag irregularities formed by intersecting a plurality of slopes 11 adjacent in a V shape. Each inclined surface 11 extends along the short direction of the light guide 1 (the direction connecting the ridge 4A and the ridge 4B). A ridge line including the vertex of the convex portion is the ridge portion 12. When the surface including the portion where the inclined surface 11 intersects on the concave side is the bottom surface 13 of the first prism 7, the angle θ1 formed by the inclined surface 11 and the bottom surface 13 is 45 degrees. The distance P1 between the adjacent ridges 12 is within the range of (2 × H1 / tan θ1) ≦ P <(10 × H1 / tan θ1), where the height from the bottom surface 13 to the ridge 12 is H1. Set as follows. In the present embodiment, P1 = 2 × H1 / tan θ1, and the inclined surfaces 11 intersect each other on the concave side. Specifically, for example, H1 = 0.25 and P1 is 0.5 mm.
　以下、導光体１に含有されているシリコーン粒子について説明する。このシリコーン粒子は、体積的に一様な散乱能が与えられた導光体であり、散乱微粒子としての球形粒子を多数含んでいる。導光体１の内部に光が入射すると、その光は散乱微粒子によって散乱することになる。 Hereinafter, the silicone particles contained in the light guide 1 will be described. This silicone particle is a light guide provided with a volumetric uniform scattering ability, and includes a large number of spherical particles as scattering fine particles. When light enters the light guide 1, the light is scattered by the scattering fine particles.
　ここで、シリコーン粒子の理論的な基礎を与えるＭｉｅ散乱理論について説明する。Ｍｉｅ散乱理論は、一様な屈折率を有する媒体（マトリックス）中に該媒体と異なる屈折率を有する球形粒子（散乱微粒子）が存在するケースについてマックスウェルの電磁方程式の解を求めたものである。光散乱粒子に相当する散乱微粒子によって散乱した散乱光の角度に依存した強度分布Ｉ（Α、Θ）は下記（１）式で表される。Αは、散乱微粒子の光学的大きさを示すサイズパラメータであり、マトリックス中での光の波長λで規格化された球形粒子（散乱微粒子）の半径ｒに相当する量である。角度Θは散乱角で、入射光の進行方向と同一方向をΘ＝１８０°にとる。 Here, the Mie scattering theory that gives the theoretical basis of silicone particles will be described. Mie scattering theory is the solution of Maxwell's electromagnetic equation for the case where spherical particles (scattering fine particles) having a refractive index different from that of the medium exist in a medium (matrix) having a uniform refractive index. . The intensity distribution I (Α, Θ) depending on the angle of the scattered light scattered by the scattering fine particles corresponding to the light scattering particles is expressed by the following equation (1). Α is a size parameter indicating the optical size of the scattering fine particles, and is an amount corresponding to the radius r of the spherical particles (scattering fine particles) normalized by the wavelength λ of light in the matrix. The angle Θ is a scattering angle, and the same direction as the traveling direction of incident light is Θ = 180 °.
　また、（１）式中のｉ１、ｉ２は（４）式で表される。そして、（２）～（４）式中の下添字ν付のａおよびｂは（５）式で表される。上添字１および下添字νを付したＰ（ｃｏｓΘ）は、Ｌｅｇｅｎｄｒｅの多項式、下添字ν付のａ、ｂは１次、２次のＲｅｃａｔｔｉ－Ｂｅｓｓｅｌ関数Ψ＊、ζ＊（ただし、「＊」は下添字νを意味する。）とその導関数とからなる。ｍはマトリックスを基準にした散乱微粒子の相対屈折率で、ｍ＝ｎｓｃａｔｔｅｒ／ｎｍａｔｒｉｘである。 Further, i 1 and i 2 in the formula (1) are represented by the formula (4). Then, a and b with the subscript ν in the expressions (2) to (4) are expressed by the expression (5). P (cos Θ) with superscript 1 and subscript ν is Legendre's polynomial, and a and b with subscript ν are first- and second-order Recati-Bessel functions Ψ * and ζ * (where “*” Means the subscript ν) and its derivative. m is the relative refractive index of the scattering fine particles based on the matrix, and m = nscatter / nmattrix.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　図３は、上記（１）～（５）式に基づいて、単一真球粒子による強度分布Ｉ（Α、Θ）を示すグラフである。この図３では、原点Ｇの位置に散乱微粒子としての真球粒子があり、下方から入射光が入射した場合の散乱光強度の角度分布Ｉ（Α、Θ）を示している。そして、原点Ｇから各曲線Ｓ１～Ｓ３までの距離が、それぞれの散乱角方向の散乱光強度である。曲線Ｓ１はΑが１．７であるときの散乱光強度、曲線Ｓ２はΑが１１．５であるときの散乱光強度、曲線Ｓ３はΑが６９．２であるときの散乱光強度を示している。なお、図３においては、散乱光強度を対数目盛で示している。このため、図３では僅かな強度差として見える部分が、実際には非常に大きな差となる。 FIG. 3 is a graph showing the intensity distribution I (Α, Θ) by a single true spherical particle based on the above equations (1) to (5). FIG. 3 shows an angular distribution I (Α, Θ) of scattered light intensity when there is a true spherical particle as a scattering fine particle at the position of the origin G and incident light is incident from below. The distance from the origin G to each of the curves S1 to S3 is the scattered light intensity in each scattering angle direction. Curve S1 shows the scattered light intensity when Α is 1.7, curve S2 shows the scattered light intensity when Α is 11.5, and curve S3 shows the scattered light intensity when Α is 69.2. Yes. In FIG. 3, the scattered light intensity is shown on a logarithmic scale. For this reason, the portion that appears as a slight difference in intensity in FIG. 3 is actually a very large difference.
　この図３に示すように、サイズパラメータΑが大きくなればなるほど（ある波長λで考えた場合は真球粒子の粒径が大きくなればなるほど）、上方（照射方向の前方）に対して指向性高く光が散乱されていることがわかる。また、実際のところ、散乱光強度の角度分布Ｉ（Α、Θ）は、入射光波長λを固定すれば、散乱子の半径ｒと、媒体および散乱微粒子の相対屈折率ｍとをパラメータとして制御することができる。なお、導光体１は、前方散乱が大きいものである。 As shown in FIG. 3, the larger the size parameter Α (the larger the particle size of the true spherical particle when considered at a certain wavelength λ), the higher the directivity with respect to the upper side (front of the irradiation direction). It can be seen that light is highly scattered. Actually, the angle distribution I (Α, Θ) of the scattered light intensity is controlled by using the radius r of the scatterer and the relative refractive index m of the medium and the scattered fine particles as parameters if the incident light wavelength λ is fixed. can do. In addition, the light guide 1 has a large forward scattering.
　このような、単一真球粒子がＮ個含まれる光散乱導光体に光を入射させると、光は真球粒子により散乱される。散乱光は光散乱導光体中を進み、他の真球粒子により再度散乱される。ある程度以上の体積濃度で粒子を添加した場合には、このような散乱が逐次的に複数回行われた後、光が光散乱導光体から出射する。このような散乱光がさらに散乱されるような現象を多重散乱現象と呼ぶ。このような多重散乱においては、透明ポリマーでの光線追跡法による解析は容易ではない。しかし、モンテカルロ法により光の挙動を追跡し、その特性を解析することはできる。それによると、入射光が無偏光の場合、散乱角の累積分布関数Ｆ（Θ）は下記の（６）式で表される。 When light is incident on such a light scattering light guide containing N single true spherical particles, the light is scattered by the true spherical particles. Scattered light travels through the light scattering light guide and is again scattered by other spherical particles. When particles are added at a volume concentration of a certain level or more, such scattering is sequentially performed a plurality of times, and then light is emitted from the light scattering light guide. A phenomenon in which such scattered light is further scattered is called a multiple scattering phenomenon. In such multiple scattering, analysis by a ray tracing method with a transparent polymer is not easy. However, the behavior of light can be traced by the Monte Carlo method and its characteristics can be analyzed. According to this, when the incident light is non-polarized light, the cumulative distribution function F (Θ) of the scattering angle is expressed by the following equation (6).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　ここで（６）式中のＩ（Θ）は、（１）式で表されるサイズパラメータΑの真球粒子の散乱強度である。強度Ｉｏの光が光散乱導光体に入射し、距離ｙを透過した後、光の強度が散乱によりＩに減衰したとすると、これらの関係は下記の（７）式で表される。 Here, I (Θ) in the equation (6) is the scattering intensity of the true spherical particle having the size parameter 表 represented by the equation (1). If light of intensity Io enters the light scattering light guide and passes through the distance y, then the intensity of the light is attenuated to I by scattering, and these relationships are expressed by the following equation (7).
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　この（７）式中のτは濁度と呼ばれ、媒体の散乱係数に相当するものであり、下記の（８）式のように粒子数Ｎに比例する。なお、（８）式中、σｓは散乱断面積である。 Τ in the equation (7) is called turbidity and corresponds to the scattering coefficient of the medium, and is proportional to the number N of particles as in the following equation (8). In the equation (8), σ s is a scattering cross section.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　（７）式から長さＬの光散乱導光体を散乱せずに透過する確率Ｐｔ（Ｌ）は下記の（９）式で表される。 From the equation (7), the probability P t (L) of transmitting through the light-scattering light guide of length L without scattering is expressed by the following equation (9).
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　反対に光路長Ｌまでに散乱される確率Ｐｓ（Ｌ）は下記の（１０）式で表される。
Figure JPOXMLDOC01-appb-M000006
 On the other hand, the probability Ps (L) scattered up to the optical path length L is expressed by the following equation (10).
Figure JPOXMLDOC01-appb-M000006
　これらの式からわかるように、濁度τを変えることにより、光散乱導光体内での多重散乱の度合いを制御することができる。 As can be seen from these equations, the degree of multiple scattering in the light scattering light guide can be controlled by changing the turbidity τ.
　以上の関係式により、散乱微粒子のサイズパラメータΑと濁度τとの少なくとも１つをパラメータとして、光散乱導光体内での多重散乱を制御可能であり、出射面６における出射光強度と散乱角も適正に設定可能である。 By the above relational expression, it is possible to control multiple scattering in the light scattering light guide using at least one of the size parameter Α and turbidity τ of the scattering fine particles as a parameter, and the outgoing light intensity and scattering angle on the outgoing surface 6 can be controlled. Can also be set appropriately.
　ここで、導光体１に含有されている光散乱粒子は、平均粒径が２．４μｍの透光性のシリコーン粒子である。また、光散乱粒子による散乱係数に相当する散乱パラメータである濁度τは、τ＝０．４９（λ＝５５０ｎｍ）である。 Here, the light scattering particles contained in the light guide 1 are translucent silicone particles having an average particle diameter of 2.4 μm. The turbidity τ, which is a scattering parameter corresponding to the scattering coefficient by the light scattering particles, is τ = 0.49 (λ = 550 nm).
（第１の実施の形態の発光装置の構成）
　図４は、本発明の第１の実施の形態に係る発光装置２１の簡略図であり、図１に示した導光体１とＬＥＤ２２との位置関係を示す図である。光源としてのＬＥＤ２２は、白色光を発する直径２．４ｍｍのチップ型のものであり、その光束は、９ｌｍである。ＬＥＤ２２は、各第１のプリズム部７に対向する位置に配置されている。本実施の形態では、たとえば、２５ｍｍ間隔で配置され、各第１のプリズム部７に向けて発光される。 (Configuration of Light Emitting Device of First Embodiment)
FIG. 4 is a simplified diagram of the light emitting device 21 according to the first embodiment of the present invention, and is a diagram showing a positional relationship between the light guide 1 and the LEDs 22 shown in FIG. The LED 22 as a light source is a chip type chip that emits white light and has a diameter of 2.4 mm, and its luminous flux is 9 lm. The LED 22 is disposed at a position facing each first prism portion 7. In the present embodiment, for example, they are arranged at intervals of 25 mm, and light is emitted toward the first prism portions 7.
　図５は、発光装置２１の光路（ＬＥＤ２２から照射された光が導光体１を透過する際の光路）Ｌの簡略を示す図であって、右端面３側から見た図である。ＬＥＤ２２から出射された光が入射面４を透過し、全反射面５にて全反射して、出射面６から出射する。 FIG. 5 is a diagram showing the simplification of the light path (light path when the light emitted from the LED 22 passes through the light guide 1) L of the light emitting device 21, and is a view seen from the right end face 3 side. The light emitted from the LED 22 passes through the incident surface 4, is totally reflected by the total reflection surface 5, and is emitted from the emission surface 6.
　図６は、発光装置２１において、ＬＥＤ２２から発せられた光が第１のプリズム部７を透過する際の光の屈折の状況を示す図である。図６に示すように、ＬＥＤ２２から出射した光Ｌ１は、第１のプリズム部７（第１の三角プリズム７Ａ）の斜面１１に入射する。そして、稜部１２よりも左端面２側にある斜面１１に入射した光Ｌ１は、右端面３側に屈折し、稜部１２よりも右端面３にある斜面１１に入射した光Ｌ１は、左端面２側に屈折する。つまり、ＬＥＤ２２から出射し第１のプリズム部７に入射した光は、第１のプリズム部７が形成されていない平面に入射したときに比べて、全体的に、左端面２と右端面３との側に発散させられる。なお、斜面１１は、入射面４の短尺方向に対しては傾斜していない。そのため、入光した光Ｌ１は、導光体１の短尺方向については、発散し難くなっている。また、導光体１に入光した光Ｌ１は、光散乱粒子によって多重散乱する。 FIG. 6 is a diagram showing the state of light refraction when the light emitted from the LED 22 passes through the first prism unit 7 in the light emitting device 21. As shown in FIG. 6, the light L1 emitted from the LED 22 is incident on the inclined surface 11 of the first prism portion 7 (first triangular prism 7A). The light L1 incident on the slope 11 on the left end surface 2 side of the ridge 12 is refracted on the right end surface 3 side, and the light L1 incident on the slope 11 on the right end surface 3 of the ridge 12 is the left end. Refracts to the surface 2 side. That is, the light emitted from the LED 22 and incident on the first prism portion 7 as a whole is compared with the case where the light is incident on a plane where the first prism portion 7 is not formed. Is diverged to the side. The inclined surface 11 is not inclined with respect to the short direction of the incident surface 4. Therefore, the incident light L <b> 1 is difficult to diverge in the short direction of the light guide 1. Further, the light L1 incident on the light guide 1 is multiple-scattered by the light scattering particles.
（第２の実施の形態の光学素子および発光装置の構成）
　図７は、本発明の第２の実施の形態に係る光学素子である導光体３１の構成を示す斜視図である。導光体３１と導光体１との差異は、出射する光を導光体３１の長尺方向に屈折させ、出射方向を出射面と直交する方向に近づける第２のプリズム部３２が、出射面６の全面に設けられている点である。その点を除いては、導光体３１と導光体１とでは構成上の差異がない。また導光体３１を用いた後述する発光装置４１と、発光装置２１とでもその点を除き、構成上の差異がない。よって、導光体１と導光体３１の共通する部材または要素、発光装置２１と発光装置４１の共通する部材または要素については、同一の符号を付して以下説明し、それらの共通部分の詳細な説明は省略する。 (Configuration of optical element and light-emitting device of second embodiment)
FIG. 7 is a perspective view showing a configuration of a light guide 31 which is an optical element according to the second embodiment of the present invention. The difference between the light guide 31 and the light guide 1 is that the second prism portion 32 that refracts the emitted light in the longitudinal direction of the light guide 31 and brings the emission direction closer to the direction orthogonal to the emission surface is emitted. This is a point provided on the entire surface 6. Except for this point, there is no structural difference between the light guide 31 and the light guide 1. Further, the light emitting device 41 described later using the light guide 31 and the light emitting device 21 have no structural difference except for this point. Therefore, members or elements that are common to the light guide 1 and the light guide 31, and members or elements that are common to the light emitting device 21 and the light emitting device 41 are denoted by the same reference numerals and described below. Detailed description is omitted.
　図８は、発光装置４１において、図７に示す入射面４の側から第２のプリズム部３２を見た図である。第２のプリズム部３２は、複数の第２の三角プリズム３２Ａを有している。これらの第２の三角プリズム３２Ａは、Ｖ字状に隣接する複数の第２の斜面４２が交差して形成されるジクザグ状の凹凸部により形成されている。そして、各第２の斜面４２は、導光体３１の短尺方向（稜部４Ａと稜部４Ｂを結ぶ方向）に沿って伸びている。第２の凸部の頂点を含む稜線が第２の稜部４３である。第２の凹部側において第２の斜面４２が交差する部分を含む面を第２のプリズムの第２の底面４４としたとき、第２の斜面４２と第２の底面４４とのなす角度θ２が８０度である。そして、隣り合う第２の稜部４３間の間隔Ｐ２は、第２の底面４４から第２の稜部４３までの高さをＨ２とした場合、（２×Ｈ２／ｔａｎθ２）≦Ｐ２＜（２０×Ｈ２／ｔａｎθ２）の範囲内となるように設定する。本実施の形態では、Ｐ２＝２×Ｈ２／ｔａｎθ２とされ、凹部側において第２の斜面４２が交差するように構成されている。具体的には、たとえば、Ｈ２＝０．３ｍｍとし、Ｐ２が０．２ｍｍとされている。 FIG. 8 is a view of the second prism portion 32 viewed from the incident surface 4 side shown in FIG. 7 in the light emitting device 41. The second prism portion 32 has a plurality of second triangular prisms 32A. These second triangular prisms 32A are formed by zigzag irregularities formed by intersecting a plurality of second inclined surfaces 42 adjacent to each other in a V shape. Each second inclined surface 42 extends along the short direction of the light guide 31 (the direction connecting the ridge 4A and the ridge 4B). The ridge line including the vertex of the second convex portion is the second ridge portion 43. When the surface including the portion where the second inclined surface 42 intersects on the second concave portion side is the second bottom surface 44 of the second prism, the angle θ2 formed by the second inclined surface 42 and the second bottom surface 44 is 80 degrees. The interval P2 between the adjacent second ridges 43 is (2 × H2 / tan θ2) ≦ P2 <(20, where the height from the second bottom surface 44 to the second ridge 43 is H2. XH2 / tan θ2) is set to be within a range. In the present embodiment, P2 = 2 × H2 / tan θ2, and the second slope 42 intersects on the concave side. Specifically, for example, H2 = 0.3 mm and P2 is 0.2 mm.
　ＬＥＤ２２から発せられた光の多くは、上述のように第１のプリズム部７により長手方向に向けて発散されて導光体３１に入射し、導光体３１の長手方向に広がりつつ全反射面５に入射する。そして、全反射面５にて全反射し、出射面６から出射する。導光体３１に入射した光は、多重散乱しながら導光体３１内を進む。図８は、出射面６から出射する光Ｌ２の光路を示している。光Ｌ２は、稜部４３よりも右端面３側にある第２の斜面４２に入射した光Ｌ２は、右端面３側に屈折し、稜部４３よりも左端面２にある第２の斜面４２に入射した光Ｌ２は、左端面２側に屈折する。つまり、出射面６から出射する光は、第２のプリズム部３２が形成されていない平面から出射するときに比べて、全体的に、出射方向が出射面６と直交する方向に近づくように屈折する。 Most of the light emitted from the LED 22 is diverged in the longitudinal direction by the first prism portion 7 as described above, enters the light guide 31, spreads in the longitudinal direction of the light guide 31, and is totally reflected. 5 is incident. Then, the light is totally reflected by the total reflection surface 5 and is emitted from the emission surface 6. The light incident on the light guide 31 travels through the light guide 31 while being multiple scattered. FIG. 8 shows an optical path of the light L2 emitted from the emission surface 6. The light L2 incident on the second inclined surface 42 on the right end surface 3 side with respect to the ridge 43 is refracted toward the right end surface 3 and the second inclined surface 42 on the left end surface 2 with respect to the ridge 43. The light L2 incident on is refracted toward the left end face 2 side. That is, the light exiting from the exit surface 6 is refracted so that the exit direction is closer to the direction orthogonal to the exit surface 6 as a whole compared to when exiting from a plane on which the second prism portion 32 is not formed. To do.
（本発明の実施の形態によって得られる主な効果）
　導光体１，３１およびそれを用いた発光装置２１，４１は、導光体１，３１の入射面４には入射する光を長尺方向に発散する（広げる）ことができる複数の第１の三角プリズム７Ａからなる第１のプリズム部７が設けられている。そのため、導光体１，３１およびそれを用いた発光装置２１，４１は、光源としてＬＥＤ２２等の光源を複数用いた場合にも、照明光の照度をより均一にし、グレアを低減することができる。 (Main effects obtained by the embodiment of the present invention)
The light guides 1, 31 and the light emitting devices 21, 41 using the light guides 1, 31 have a plurality of first light that can diverge (expand) incident light on the incident surface 4 of the light guides 1, 31 in the longitudinal direction. A first prism portion 7 composed of a triangular prism 7A is provided. Therefore, the light guides 1 and 31 and the light emitting devices 21 and 41 using the light guides 1 and 31 can make the illumination light illuminance more uniform and reduce glare even when a plurality of light sources such as the LEDs 22 are used as the light source. .
　図９は、比較例として、導光体１からプリズム部７及び光散乱粒子を省略した導光体を用いて、発光装置２１と同様の発光装置を構成した場合の出射面６に相当する面における輝度分布を示す図である。比較例の導光体は、第１のプリズム部７に相当する部分が平面状となっている。左側の図は、出射面６に相当する面における輝度の分布を色の濃淡で表わしており、色が黒に近づくほど輝度が小さく、色が白に近づくほど輝度が大きいことを示している。右側の図は、比較例の導光体の出射面６に相当する面の短尺方向の真ん中のラインの輝度分布を示すグラフである。比較例の発光装置は、出射面６に相当する面の長手方向に並ぶ縞状に発光部分が存在し、暗い部分と明るい部分との輝度の差が約１２０００ｃｄ／ｍ２であることがわかる。 FIG. 9 shows a surface corresponding to the emission surface 6 when a light-emitting device similar to the light-emitting device 21 is configured by using a light-guiding body in which the prism portion 7 and the light scattering particles are omitted from the light-guiding body 1 as a comparative example. It is a figure which shows the luminance distribution in. In the light guide of the comparative example, the portion corresponding to the first prism portion 7 is planar. The diagram on the left represents the luminance distribution on the surface corresponding to the exit surface 6 by the color shading, and shows that the luminance decreases as the color approaches black and increases as the color approaches white. The figure on the right side is a graph showing the luminance distribution of the middle line in the short direction of the surface corresponding to the exit surface 6 of the light guide of the comparative example. It can be seen that the light emitting device of the comparative example has light emitting portions in the form of stripes arranged in the longitudinal direction of the surface corresponding to the emission surface 6, and the difference in luminance between the dark portion and the bright portion is about 12000 cd / m 2 .
　図１０は、比較例の発光装置と同条件で発光させた本発明の実施の形態に係る発光装置２１であって、光散乱粒子を含有させない導光体を用いたものの出射面６の輝度分布を示す図である。左側の図は、出射面６における輝度の分布を色の濃淡で表わしており、右側の図は、出射面６の短尺方向の真ん中のラインの輝度分布を示すグラフである。図１０に示すように、発光装置２１は、出射面６の長手方向に、比較例の発光装置よりも細かく並ぶ縞状に発光部分が存在する。そして、暗い部分と明るい部分との輝度の差が約５０００ｃｄ／ｍ２である。このことから、発光装置２１は、比較例の発光装置に比べて光を均一に照射することができることがわかる。 FIG. 10 is a light-emitting device 21 according to an embodiment of the present invention that emits light under the same conditions as the light-emitting device of the comparative example, and uses a light guide that does not contain light scattering particles. FIG. The diagram on the left shows the luminance distribution on the exit surface 6 with shades of color, and the diagram on the right is a graph showing the brightness distribution of the middle line of the exit surface 6 in the short direction. As shown in FIG. 10, the light emitting device 21 has light emitting portions in the longitudinal direction of the emission surface 6 in stripes arranged more finely than the light emitting device of the comparative example. The difference in luminance between the dark part and the bright part is about 5000 cd / m 2 . This shows that the light-emitting device 21 can irradiate light more uniformly than the light-emitting device of the comparative example.
　また、導光体１，３１は、第１のプリズム部７を構成する第１の三角プリズム７Ａは、斜面１１と底面１３とのなす角度θ１を２０度以上７０度以下の４５度としており、かつ隣接する稜部１２の間の間隔Ｐ１が、底面１３から稜部１２までの高さをＨ１とした場合、（２×Ｈ１／ｔａｎθ１）≦Ｐ１＜（１０×Ｈ１／ｔａｎθ１）の範囲となるように設定している。本実施の形態では、Ｐ１＝２×Ｈ１／ｔａｎθ１とされ、凹部側において斜面１１が交差するように構成されている。具体的には、たとえば、Ｈ１＝０．２５とし、Ｐ１が０．５ｍｍとされている。ここで、角度θ１を２０度以上とすることによって、十分に光を広げる効果が得られる。また、角度θ１を７０度以下とすることにより、隣接するプリズム同士での光の干渉を抑制でき、より光を広げる効果が得られる。なお、（２×ｈ／ｔａｎθ）≦Ｐとしているのは、物理的制約によるものであり、Ｐ１＝２×Ｈ１／ｔａｎθ１とすることで、ＬＥＤ２２から照射された光を最も効率よく長尺方向に向けて発散させることができる。また、Ｐ１＜（１０×Ｈ１／ｔａｎθ１）の範囲であれば、隣接する第１の三角プリズム７Ａ間の間隔が開き、隣接する第１の三角プリズム７Ａとの間に平面部が形成されても、ＬＥＤ２２から照射された光を効率よく長尺方向に向けて発散させることができる。 In addition, the light guides 1 and 31 are such that the first triangular prism 7A constituting the first prism unit 7 has an angle θ1 formed by the inclined surface 11 and the bottom surface 13 of 45 degrees of 20 degrees or more and 70 degrees or less. Further, the interval P1 between the adjacent ridges 12 is in the range of (2 × H1 / tan θ1) ≦ P1 <(10 × H1 / tan θ1) where the height from the bottom surface 13 to the ridge 12 is H1. It is set as follows. In the present embodiment, P1 = 2 × H1 / tan θ1, and the inclined surfaces 11 intersect on the concave side. Specifically, for example, H1 = 0.25 and P1 is 0.5 mm. Here, by setting the angle θ1 to 20 degrees or more, an effect of sufficiently spreading light can be obtained. In addition, by setting the angle θ1 to 70 degrees or less, it is possible to suppress the interference of light between adjacent prisms and to obtain an effect of further spreading the light. Note that (2 × h / tan θ) ≦ P is due to physical restrictions. By setting P1 = 2 × H1 / tan θ1, the light emitted from the LED 22 is most efficiently transmitted in the long direction. Can diverge towards. If P1 <(10 × H1 / tan θ1), the interval between the adjacent first triangular prisms 7A is increased, and a plane portion is formed between the adjacent first triangular prisms 7A. The light emitted from the LED 22 can be efficiently diverged in the longitudinal direction.
　また、導光体１，３１は、出射した光を多重散乱させる光散乱粒子を含有し、光散乱粒子は、粒径が２μｍ～９μｍの透光性のシリコーン粒子である。この粒径範囲とすることで、導光体１の入射光の前方散乱を適切な範囲で大きくすることができる。そして、光散乱粒子による散乱係数に相当する散乱パラメータである濁度をτとした場合、τ＞０．０１の範囲である０．４９（λ＝５５０ｎｍ）としている。濁度τをこの範囲とすることによって、入射光の多重散乱をより活発化させることができる。 The light guides 1 and 31 contain light scattering particles that multiple-scatter the emitted light, and the light scattering particles are translucent silicone particles having a particle diameter of 2 μm to 9 μm. By setting it as this particle size range, the forward scattering of the incident light of the light guide 1 can be increased within an appropriate range. When turbidity, which is a scattering parameter corresponding to a scattering coefficient by light scattering particles, is τ, 0.49 (λ = 550 nm) is set in a range of τ> 0.01. By setting the turbidity τ within this range, multiple scattering of incident light can be further activated.
　図１１は、比較例の発光装置と同条件で発光させた本発明の実施の形態に係る発光装置２１であって、光散乱粒子を含有させない導光体を用いたものの出射面６から４０ｍｍ上方に離れた部分の出射した光の照度分布を示す図である。左側の図は、図９と同様に照度の分布を色の濃淡で表わしており、右側の図は、出射面６から照射された光の照射域の中央部について導光体１の長尺方向に沿う方向の照度分布を示すグラフである。図１２は、比較例の発光装置と同条件で発光させた本発明の実施の形態に係る発光装置２１の出射面６から４０ｍｍ上方に離れた部分の照度分布を示す図であり、左側の図は、出射面６から出射された光の照度の分布を色の濃淡で表わしており、右側の図は、出射面６から照射された光の照射域の中央部について導光体１の長尺方向に沿う方向の照度分布を示すグラフである。なお、照度は、出射面６から４０ｍｍ離れた位置で評価している。図１１に示す光散乱粒子を含有させない導光体を用いた発光装置は、照光部分が若干縞状となっているのに対して、図１２に示す光散乱粒子を含有させた導光体１を用いた発光装置２１は、照光部分が縞状となっておらず、均一となっている。 FIG. 11 shows a light emitting device 21 according to an embodiment of the present invention that emits light under the same conditions as the light emitting device of the comparative example, and uses a light guide that does not contain light scattering particles 40 mm above the emission surface 6. It is a figure which shows the illuminance distribution of the light which the part which left | separated to [in FIG. The diagram on the left represents the illuminance distribution in shades of color as in FIG. 9, and the diagram on the right shows the longitudinal direction of the light guide 1 at the center of the irradiation area of the light irradiated from the exit surface 6. It is a graph which shows the illumination intensity distribution of the direction in alignment with. FIG. 12 is a diagram showing the illuminance distribution of a portion 40 mm above the exit surface 6 of the light emitting device 21 according to the embodiment of the present invention that emits light under the same conditions as the light emitting device of the comparative example. Represents the distribution of the illuminance of the light emitted from the emission surface 6 in shades of color, and the figure on the right side shows the length of the light guide 1 at the center of the irradiation area of the light emitted from the emission surface 6. It is a graph which shows the illuminance distribution of the direction along a direction. The illuminance is evaluated at a position 40 mm away from the emission surface 6. In the light emitting device using the light guide that does not contain the light scattering particles shown in FIG. 11, the light-emitting body 1 contains light scattering particles shown in FIG. In the light emitting device 21 using, the illuminated portion is not striped and is uniform.
　また、導光体３１は、出射面６に出射する光を長尺方向に屈折させ、出射方向を出射面６と直交する方向に近づけるように屈折させる複数の第２の三角プリズム３２Ａからなる第２のプリズム部３２が設けられている。そのため、光の出射方向を出射面６から長尺方向に広がった方向とするのを抑制でき、発光装置４１の光の出射方向を出射面６と直交する方向に近づけることができる。 The light guide 31 is composed of a plurality of second triangular prisms 32A made of a plurality of second triangular prisms 32A that refract the light emitted to the emission surface 6 in the longitudinal direction and refract the emission direction so as to approach the direction orthogonal to the emission surface 6. Two prism portions 32 are provided. Therefore, it is possible to prevent the light emission direction from extending in the longitudinal direction from the emission surface 6, and the light emission direction of the light emitting device 41 can be brought closer to the direction orthogonal to the emission surface 6.
　図１３は、比較例の発光装置と同条件で発光させた本発明の実施の形態に係る発光装置２１の出射面６の輝度分布を示す図である。左側の図は、輝度の分布を色の濃淡で表わしており、右側の図は、比較例の導光体の出射面６に相当する面の短尺方向の真ん中のラインの輝度分布を示すグラフである。図１４は、比較例の発光装置と同条件で発光させた本発明の実施の形態に係る発光装置４１の出射面６の輝度分布を示す図である。第２のプリズム部３２が無い発光装置２１は、図１３に示すように、輝度の高い部分と低い部分が縞状に表れている。ただし、光散乱粒子が含有されていない導光体を用いた図１０に示す輝度分布より輝度は均一である。また、明るい部分の輝度が約６０００ｃｄ／ｍ２である。一方、図１４に示すように、第２のプリズム部３２がある発光装置４１は、輝度の高い部分と低い部分が縞状に表れておらず、輝度が均一である。また、明るい部分の輝度が約１１０００ｃｄ／ｍ２であり、発光装置２１に比べて、輝度が大きいことがわかる。 FIG. 13 is a diagram showing a luminance distribution on the exit surface 6 of the light emitting device 21 according to the embodiment of the present invention that emits light under the same conditions as the light emitting device of the comparative example. The diagram on the left shows the luminance distribution in shades of color, and the diagram on the right is a graph showing the luminance distribution of the middle line in the short direction of the surface corresponding to the exit surface 6 of the light guide of the comparative example. is there. FIG. 14 is a diagram showing a luminance distribution of the emission surface 6 of the light emitting device 41 according to the embodiment of the present invention that emits light under the same conditions as the light emitting device of the comparative example. As shown in FIG. 13, in the light emitting device 21 without the second prism portion 32, a high luminance portion and a low luminance portion appear in stripes. However, the luminance is more uniform than the luminance distribution shown in FIG. 10 using a light guide that does not contain light scattering particles. Further, the brightness of the bright part is about 6000 cd / m 2 . On the other hand, as shown in FIG. 14, in the light emitting device 41 having the second prism portion 32, the high luminance portion and the low luminance portion do not appear in stripes, and the luminance is uniform. In addition, the luminance of the bright portion is about 11000 cd / m 2 , which indicates that the luminance is higher than that of the light emitting device 21.
　また、第２のプリズム部３２を構成する第２の三角プリズム３２Ａは、第２の斜面４２と第２の底面４４とのなす角度θ２が５０度以上９０度未満の範囲内の８０度であり、かつ隣接する稜部４３間の間隔Ｐ２が、底面４４から稜部４３までの高さをＨ２とした場合、
（２×Ｈ２／ｔａｎθ２）≦Ｐ２＜（２０×Ｈ２／ｔａｎθ２） の範囲内となるように設定している。本実施の形態では、Ｐ２＝２×Ｈ２／ｔａｎθ２とされ、凹部側において斜面４２が交差するように構成されている。具体的には、たとえば、Ｈ２＝０．３ｍｍとし、Ｐ２が０．２ｍｍとされている。角度θ２を５０度以上としているのは、出射光を出射面６に対して直交する方向に向けて屈折させ易くし、出射面６の輝度をより均一にするためである。なお、角度θ２を９０度未満としている理由、および（２×Ｈ／ｔａｎθ２）≦Ｐ２としている理由は、物理的制約によるものである。また、Ｐ２＜（２０×Ｈ２／ｔａｎθ２）の範囲であれば、隣接する第２の三角プリズム３２間の間隔が開き、隣接する第２の三角プリズム３２との間に平面部が形成されても、出射面６から出射する光の出射方向を長尺方向に広がることを抑制でき、発光装置４１の光の出射方向を出射面６と直交する方向に近づけることができる。 The second triangular prism 32A constituting the second prism portion 32 has an angle θ2 formed by the second inclined surface 42 and the second bottom surface 44 of 80 degrees within a range of 50 degrees or more and less than 90 degrees. And when the interval P2 between the adjacent ridges 43 is H2 from the bottom 44 to the ridge 43,
It is set to be in the range of (2 × H2 / tan θ2) ≦ P2 <(20 × H2 / tan θ2). In the present embodiment, P2 = 2 × H2 / tan θ2, and the inclined surfaces 42 intersect with each other on the concave side. Specifically, for example, H2 = 0.3 mm and P2 is 0.2 mm. The reason why the angle θ2 is set to 50 degrees or more is to make it easier to refract the emitted light in the direction orthogonal to the emission surface 6 and to make the luminance of the emission surface 6 more uniform. The reason why the angle θ2 is less than 90 degrees and the reason why (2 × H / tan θ2) ≦ P2 are due to physical restrictions. If P2 <(20 × H2 / tan θ2), the interval between the adjacent second triangular prisms 32 is widened, and a plane portion is formed between the adjacent second triangular prisms 32. Further, it is possible to suppress the emission direction of the light emitted from the emission surface 6 from spreading in the longitudinal direction, and the light emission direction of the light emitting device 41 can be brought close to the direction orthogonal to the emission surface 6.
　また、ＬＥＤ２２は、導光体１，３１の長尺方向に複数等間隔に配置され、入射面４のＬＥＤ２２と対向しない部分には、第１のプリズム部７が設けられないプリズム未形成部８が存在している。ＬＥＤ２２から発せられる光のうち、横方向に広がり第１のプリズム７に入射することができない光の一部は、プリズム未形成部８にて導光体１，３１へと入射される。横方向に広がってプリズム未形成部８に入射する光は、既に導光体１，３１の長尺方向に広がっているため、第１のプリズム７にてさらに屈折させる必要はない。したがって、第１のプリズム７の形成箇所を減らすことができ、製造時の工程等を簡略化することができる。 Further, the LEDs 22 are arranged at a plurality of equal intervals in the longitudinal direction of the light guides 1, 31, and the prism-unformed portion 8 in which the first prism portion 7 is not provided in the portion of the incident surface 4 that does not face the LED 22. Is present. Of the light emitted from the LED 22, a part of the light that spreads in the lateral direction and cannot enter the first prism 7 is incident on the light guides 1 and 31 in the prism non-formation portion 8. Light that spreads in the lateral direction and enters the prism-unformed portion 8 has already spread in the longitudinal direction of the light guides 1 and 31, and therefore does not need to be further refracted by the first prism 7. Therefore, the formation place of the 1st prism 7 can be reduced, and the process at the time of manufacture, etc. can be simplified.
　また、導光体１，３１の入射面４と全反射面５とのなす角αは、４０度、全反射面５と出射面６とのなす角βは、５０度、出射面６と入射面４とのなす角γは、９０度とされている。すなわち、出射面６の幅寸法が入射面４の幅寸法よりも小さくされている。そのため、発光装置２１，４１の設置環境の関係で、出射面６の幅寸法を小さくしなければならない場合に、導光体１，３１は有利な形状である。 The angle α formed between the incident surface 4 and the total reflection surface 5 of the light guides 1 and 31 is 40 degrees, and the angle β formed between the total reflection surface 5 and the output surface 6 is 50 degrees, and the output surface 6 and the incident surface 6 are incident. The angle γ made with the surface 4 is 90 degrees. That is, the width dimension of the exit surface 6 is made smaller than the width dimension of the entrance surface 4. Therefore, the light guides 1 and 31 have an advantageous shape when the width dimension of the emission surface 6 must be reduced due to the installation environment of the light emitting devices 21 and 41.
（他の形態）
　導光体１，３１は、平面状の左端面２から右端面３に向かう方向に長尺な三角柱の側面を有し、その３つの側面がそれぞれ、光が入射する入射面４、入射した光を全反射する全反射面５、全反射した光を外部へ出射する出射面６であり、入射面４には入射する光を長尺方向に広げる複数の第１の三角プリズム７Ａからなる第１のプリズム部７が設けられ、第１の三角プリズム７ＡはＶ字状に隣接する複数の斜面１１が交差して形成されるジクザグ状の凹凸部（鋸歯状のプリズム部）により形成され、凸部の頂点を含む稜線を稜部１２とし、凹部側において斜面１１が交差する部分を含む面を第１のプリズム７の底面１３としたとき、斜面１１と底面１３とのなす角度θ１が２０度以上７０度以下であり、かつ隣り合う稜部１２間の間隔Ｐ１が、底面１３から稜部１２までの高さをＨ１とした場合、（２×Ｈ１／ｔａｎθ１）≦Ｐ１＜（１０×Ｈ１／ｔａｎθ１）である。 (Other forms)
The light guides 1 and 31 have triangular prism side surfaces that are long in the direction from the planar left end surface 2 to the right end surface 3, and the three side surfaces are respectively an incident surface 4 on which light is incident and incident light. Is a total reflection surface 5 that totally reflects light, and an emission surface 6 that emits the totally reflected light to the outside. The incident surface 4 includes a first triangular prism 7A that spreads incident light in the longitudinal direction. The prism portion 7 is provided, and the first triangular prism 7A is formed by a zigzag uneven portion (saw-toothed prism portion) formed by crossing a plurality of slopes 11 adjacent to each other in a V shape. When the ridge line including the apex of the first prism 7 is defined as the ridge portion 12 and the surface including the portion where the inclined surface 11 intersects on the concave side is the bottom surface 13 of the first prism 7, the angle θ1 formed by the inclined surface 11 and the bottom surface 13 is 20 degrees or more. The interval P1 between the adjacent ridges 12 is 70 degrees or less. If from the bottom surface 13 to the ridge 12 height was H1, a (2 × H1 / tanθ1) ≦ P1 <(10 × H1 / tanθ1).
　ここで、左端面２、右端面３、入射面４および出射面６は、平面状とされていなくてもよく、たとえば、丸みを帯びた凸形状とされていても良い。また、斜面１１と底面１３とのなす角度θ１を２０度以上７０度以下とすること、および第１の三角プリズム７Ａの稜部１２間の間隔Ｐ１が、底面１３から稜部１２までの高さをＨ１とした場合、（２×Ｈ１／ｔａｎθ１）≦Ｐ１＜（１０×Ｈ１／ｔａｎθ１）とすることのいずれか一方または双方を採用しないこととしてもよい。 Here, the left end surface 2, the right end surface 3, the entrance surface 4 and the exit surface 6 do not have to be flat, and may be, for example, rounded convex shapes. In addition, the angle θ1 formed by the slope 11 and the bottom surface 13 is set to 20 degrees or more and 70 degrees or less, and the interval P1 between the ridge portions 12 of the first triangular prism 7A is a height from the bottom surface 13 to the ridge portion 12. When H1 is H1, either or both of (2 × H1 / tan θ1) ≦ P1 <(10 × H1 / tan θ1) may not be adopted.
　また、導光体１，３１は、入射した光を多重散乱させる光散乱粒子を含有し、光散乱粒子は、粒径が２μｍ～９μｍの範囲内の粒径が２．４μｍの透光性のシリコーン粒子であり、光散乱粒子による散乱係数に相当する散乱パラメータである濁度をτとした場合、τ＞０．０１の範囲内であるτ＝０．４９（λ＝５５０ｎｍ）である。しかし、光散乱粒子は導光体１，３１に含有させないこととしても良い。また、含有させる場合であっても、光散乱粒子の粒径を２μｍ～９μｍとすること、透光性のシリコーン粒子とすること、τ＞０．０１とすることのいずれか１つ、２つまたは全部は必要ない。たとえば、光の前方散乱を適切な範囲で大きくするためには、粒子径が５μｍから９μｍの球状かつ透光性のシリコーン粒子を用いることがより好ましい場合がある。 In addition, the light guides 1 and 31 contain light scattering particles that multiple-scatter incident light. The light scattering particles have a light-transmitting property with a particle diameter of 2.4 μm within a range of 2 μm to 9 μm. When turbidity, which is a silicone particle and is a scattering parameter corresponding to the scattering coefficient by the light scattering particles, is τ, τ = 0.49 (λ = 550 nm) which is in the range of τ> 0.01. However, the light scattering particles may not be contained in the light guides 1 and 31. Even if it is included, any one of the two of the light scattering particles having a particle diameter of 2 μm to 9 μm, a translucent silicone particle, and τ> 0.01. Or not all. For example, in order to increase the forward scattering of light within an appropriate range, it may be more preferable to use spherical and translucent silicone particles having a particle diameter of 5 μm to 9 μm.
　また、導光体３１は、出射面６には出射する光を前記長尺方向に屈折させ、出射方向を出射面と直交する方向に近づける複数の第２の三角プリズム３２Ａからなる第２のプリズム部３２を設けている。しかし、導光体１のように第２のプリズム部３２は、設けなくても良い。 In addition, the light guide 31 refracts outgoing light on the outgoing surface 6 in the longitudinal direction, and a second prism composed of a plurality of second triangular prisms 32A that brings the outgoing direction closer to a direction orthogonal to the outgoing surface. A portion 32 is provided. However, the second prism portion 32 may not be provided like the light guide 1.
　また、導光体３１は、第２のプリズム部を構成する第２のプリズム３２はＶ字状に隣接する複数の第２の斜面４２が交差して形成されるジクザグ状の凹凸部（鋸歯状のプリズム部）により形成され、第２の凸部の頂点を含む稜線を稜部４３とし、第２の凹部の側において斜面４２が交差する部分を含む面を第２のプリズムの第２の底面４４としたとき、第２の斜面４２と第２の底面４４とのなす角度θ２が５０度以上９０度未満であり、かつ隣り合う第２の稜部４３間の間隔Ｐ２が、第２の底面４４から第２の稜部４３までの高さをＨ２とした場合、（２×Ｈ２／ｔａｎθ２）≦Ｐ２＜（２０×Ｈ２／ｔａｎθ２）としている。しかし、第２の斜面４２と第２の底面４４とのなす角度θ２を５０度以上９０度未満としていること、および（２×Ｈ２／ｔａｎθ２）≦Ｐ２＜（２０×Ｈ２／ｔａｎθ２）とすることのいずれか一方または双方を採用しないこととしてもよい。 The light guide 31 has a zigzag uneven portion (sawtooth shape) formed by intersecting a plurality of second inclined surfaces 42 adjacent to each other in a V shape. And a ridge line including the apex of the second convex portion as a ridge portion 43, and a surface including a portion where the inclined surface 42 intersects on the second concave portion side is a second bottom surface of the second prism. 44, the angle θ2 formed by the second inclined surface 42 and the second bottom surface 44 is not less than 50 degrees and less than 90 degrees, and the interval P2 between the adjacent second ridges 43 is the second bottom surface. When the height from 44 to the second ridge 43 is H2, (2 × H2 / tan θ2) ≦ P2 <(20 × H2 / tan θ2). However, the angle θ2 formed by the second inclined surface 42 and the second bottom surface 44 is set to 50 degrees or more and less than 90 degrees, and (2 × H2 / tan θ2) ≦ P2 <(20 × H2 / tan θ2). Either or both of these may not be adopted.
　また、発光装置２１，４１は、平面状の左端面２から平面状の右端面３に向かう方向に長尺な三角柱の側面を有し、その３つの側面がそれぞれ、光が入射する入射面４、入射した光を全反射する全反射面５、全反射した光を外部へ出射する出射面６であり、入射面４には入射する光を長尺方向に広げる複数のプリズムからなるプリズム部７が設けられた導光体１，３１を備え、入射面４側には、プリズム部７と対向する位置に入射面６に向かって発光するＬＥＤ２２が配置されている。 The light emitting devices 21 and 41 have triangular prism side surfaces extending in a direction from the planar left end surface 2 to the planar right end surface 3, and the three side surfaces are incident surfaces 4 on which light is incident. A total reflection surface 5 that totally reflects the incident light, and an exit surface 6 that emits the totally reflected light to the outside. The incident surface 4 has a prism portion 7 composed of a plurality of prisms that spread the incident light in the longitudinal direction. Are provided, and an LED 22 that emits light toward the incident surface 6 is disposed at a position facing the prism portion 7 on the incident surface 4 side.
　ここで、左端面２および右端面３は、平面状とされていなくてもよく、たとえば、丸みを帯びた凸形状とされていても良い。また、ＬＥＤ２２に代えて他の光源、たとえば光密度の高い放電光（キセノンランプ、水銀灯）やレーザを用いても良い。 Here, the left end surface 2 and the right end surface 3 do not have to be flat, and may be, for example, rounded convex shapes. Further, instead of the LED 22, another light source, for example, discharge light (xenon lamp, mercury lamp) or laser with high light density may be used.
　また、発光装置２１，４１は、ＬＥＤ２２が導光体１，３１の長尺方向に複数等間隔に配置されている。しかし、ＬＥＤ２２は、等間隔に配置されている必要はなく、偏在していても良い。また、導光体１，３１の入射面４のＬＥＤ２２と対向しない部分には、第１のプリズム部７が設けられないプリズム未形成部８が存在している。しかし、プリズム未形成部８は存在させずに入射面４全域に第１のプリズム部７を形成しても良い。 Further, in the light emitting devices 21 and 41, a plurality of LEDs 22 are arranged at equal intervals in the longitudinal direction of the light guides 1 and 31. However, the LEDs 22 do not have to be arranged at equal intervals and may be unevenly distributed. Further, in the portion of the incident surface 4 of the light guides 1, 31 that does not face the LED 22, there is a prism non-formed portion 8 where the first prism portion 7 is not provided. However, the first prism portion 7 may be formed over the entire incident surface 4 without the prism-unformed portion 8 being present.
　また、複数のＬＥＤ２２の発光色は、白色としているが、複数のＬＥＤ２２の発光色を異ならせても良い。そして、導光体１，３１内で混色させ、出射面６からその混色光を発するようにしても良い。また、ＬＥＤ２２は、チップ型のものに限らずディスクリート型のＬＥＤ等を採用できる。 Further, although the emission color of the plurality of LEDs 22 is white, the emission color of the plurality of LEDs 22 may be different. Then, the light guides 1 and 31 may be mixed in color, and the mixed color light may be emitted from the emission surface 6. Further, the LED 22 is not limited to a chip type but can be a discrete type LED or the like.
　さらに、導光体１、３１には、ＰＭＭＡ製のものを用いているが、その他のアクリル酸エステルあるいはメタクリル酸エステルの重合体で、透明性の高い非晶質の合成樹脂であるアクリル樹脂、ポリスチレン、ポリカーボネート等の他の透光性樹脂やガラス等を材質としたものを用いることができる。 Further, the light guides 1 and 31 are made of PMMA, but other acrylic ester or methacrylic ester polymer, which is an acrylic resin that is a highly transparent amorphous resin, Other light-transmitting resins such as polystyrene and polycarbonate, and those made of glass can be used.
　図１５は、本発明の第１の実施の形態に係る発光装置２１の変形例で、導光体１の左端面２、右端面３、入射面４および全反射面５を覆う反射部材５１を、発光装置２１に取り付けた状態を示す図である。この反射部材５１は、光反射率の高い材料、たとえば鏡面材料、金属材料、白色セラミック材料等を有し、導光体１の出射面６以外から漏れ出る光を反射させて導光体１内へと戻す役割をする。すると、導光体１の出射面６以外から漏れ出ることのある光を出射面６から出射できるため、発光効率の高い発光装置を提供できる。また、反射部材５１はＬＥＤ２２をはめ込み固定する孔部５２を有している。このため、孔部５２がＬＥＤ２２を保持し、ＬＥＤ２２の位置決めをすることができる。なお、孔部５２は設けず、反射部材５１の内面にＬＥＤ２２を固定することとしても良いし、反射部材５１は、ＬＥＤ２２を固定しないこととしても良い。また、反射部材５１は、発光装置４１に取り付けることとしても良い。さらに、反射部材５１は、導光体１の左端面２、右端面３、入射面４および全反射面５の全体を覆っているが、これらのいずれか１つ、２つまたは３つを覆わないようにしたり、左端面２、右端面３、入射面４および全反射面５のそれぞれの一部を覆うようにしても良い。たとえば、反射部材５１は、プリズム部７によって広げられた光が左端面２、右端面３から出射するのを抑えるため、左端面２、右端面３に対向する部分の光反射率を高めることとしても良い。 FIG. 15 is a modification of the light emitting device 21 according to the first embodiment of the present invention, and shows a reflecting member 51 that covers the left end surface 2, the right end surface 3, the incident surface 4, and the total reflection surface 5 of the light guide 1. It is a figure which shows the state attached to the light-emitting device 21. FIG. The reflecting member 51 includes a material having a high light reflectivity, for example, a mirror surface material, a metal material, a white ceramic material, and the like, and reflects light leaking from other than the exit surface 6 of the light guide 1 to thereby reflect the inside of the light guide 1. Play the role of returning to. Then, since light that may leak from other than the emission surface 6 of the light guide 1 can be emitted from the emission surface 6, a light emitting device with high luminous efficiency can be provided. The reflecting member 51 has a hole 52 for fitting and fixing the LED 22. For this reason, the hole part 52 hold | maintains LED22 and can position LED22. The hole 52 may not be provided, and the LED 22 may be fixed to the inner surface of the reflecting member 51, or the reflecting member 51 may not fix the LED 22. Further, the reflecting member 51 may be attached to the light emitting device 41. Further, the reflecting member 51 covers the entire left end surface 2, right end surface 3, incident surface 4 and total reflection surface 5 of the light guide 1, but covers any one, two or three of these. Alternatively, the left end surface 2, the right end surface 3, the incident surface 4, and the total reflection surface 5 may be partially covered. For example, the reflecting member 51 increases the light reflectance of the portion facing the left end surface 2 and the right end surface 3 in order to suppress the light spread by the prism portion 7 from being emitted from the left end surface 2 and the right end surface 3. Also good.
　１，３１　導光体（光学素子）
　２　左端面
　３　右端面
　４　入射面
　５　全反射面
　６　出射面
　７　プリズム部
　７Ａ　第１の三角プリズム
　８　プリズム部未形成部（プリズム部が設けられない部分）
１１　斜面
１２　稜部
１３　底面
２１，４１　発光装置
２２　ＬＥＤ（光源）
３２　第２のプリズム部
３２Ａ　第２の三角プリズム
４２　第２の斜面
４３　第２の稜部
４４　第２の底面
　τ　濁度
　θ１　第１の三角プリズムの底角
　θ２　第２の三角プリズムの底角
　Ｐ１　隣り合う稜部間の間隔（第１の三角プリズムの隣り合う稜部間の間隔）
　Ｐ２　第２の頂点間ピッチ（第２の三角プリズムの隣り合う稜部間の間隔）
　Ｈ１　底面から稜部までの高さ（第２の三角プリズムの底面から第２の三角プリズムの稜部までの高さ）
　Ｈ２　第２の底面から第２の稜部までの高さ（第２の三角プリズムの底面から第２の三角プリズムの稜部までの高さ） 1,31 Light guide (optical element)
2 Left end surface 3 Right end surface 4 Incident surface 5 Total reflection surface 6 Outgoing surface 7 Prism portion 7A First triangular prism 8 Prism portion unformed portion (portion where no prism portion is provided)
11 Slope 12 Ridge 13 Bottom 21, 41 Light Emitting Device 22 LED (Light Source)
32 Second prism portion 32A Second triangular prism 42 Second slope 43 Second ridge portion 44 Second bottom surface τ Turbidity θ1 Base angle of first triangular prism θ2 Base angle of second triangular prism P1 Interval between adjacent ridges (interval between adjacent ridges of the first triangular prism)
P2 Pitch between second vertices (space between adjacent ridges of the second triangular prism)
H1 Height from the bottom to the ridge (height from the bottom of the second triangular prism to the ridge of the second triangular prism)
H2 Height from the second bottom surface to the second ridge (height from the bottom surface of the second triangular prism to the ridge portion of the second triangular prism)

Claims (13)

  1. 　三角柱を呈する導光部を有し、
    　上記導光部の３つの側面のうち、１つの側面を光が入射する入射面とし、他の１つの側面を上記入射した光を全反射する全反射面とし、残りの１つの側面を上記全反射した光を外部へ出射する出射面とし、
    　上記入射面には、上記全反射面を含む平面と上記出射面を含む平面とに交差する方向に稜線方向を向けた稜部を有する複数の第１の三角プリズムからなる第１のプリズム部が設けられる、
    ことを特徴とする光学素子。     Having a light guide that presents a triangular prism;
    Of the three side surfaces of the light guide unit, one side surface is an incident surface on which light is incident, the other one side surface is a total reflection surface that totally reflects the incident light, and the remaining one side surface is the entire surface. Let the reflected light be an exit surface that exits to the outside,
    The incident surface includes a first prism portion including a plurality of first triangular prisms having a ridge portion whose ridge line direction is directed in a direction intersecting the plane including the total reflection surface and the plane including the emission surface. Provided,
    An optical element.
  2. 　請求項１に記載の光学素子において、
    　前記第１の三角プリズムの底角θ１が２０度以上７０度以下であり、かつ、前記複数の第１の三角プリズムの隣り合う稜部間の間隔Ｐ１が、前記第１の三角プリズムの底面から前記稜部までの高さをＨ１とした場合、
    　（２×Ｈ１／ｔａｎθ１）≦Ｐ１＜（１０×Ｈ１／ｔａｎθ１）
    であることを特徴とする光学素子。     The optical element according to claim 1,
    The base angle θ1 of the first triangular prism is not less than 20 degrees and not more than 70 degrees, and the interval P1 between adjacent ridges of the plurality of first triangular prisms is from the bottom surface of the first triangular prism. When the height to the ridge is H1,
    (2 × H1 / tan θ1) ≦ P1 <(10 × H1 / tan θ1)
    An optical element characterized by the above.
  3. 　請求項１記載の光学素子において、
    　入射した光を多重散乱させる光散乱粒子を含有し、
    　上記光散乱粒子は、粒径が２μｍ～９μｍの透光性のシリコーン粒子であり、
    　上記光散乱粒子による散乱係数に相当する散乱パラメータである濁度をτとした場合、τ＞０．０１であることを特徴とする光学素子。     The optical element according to claim 1, wherein
    Contains light scattering particles that scatter incident light multiple times,
    The light scattering particles are translucent silicone particles having a particle size of 2 μm to 9 μm,
    An optical element, wherein τ> 0.01 when turbidity which is a scattering parameter corresponding to a scattering coefficient by the light scattering particles is τ.
  4. 　請求項１記載の光学素子において、
    　前記出射面には前記複数の第１の三角プリズムの配置方向に沿って配置される複数の第２の三角プリズムからなる第２のプリズム部が設けられていることを特徴とする光学素子。     The optical element according to claim 1, wherein
    An optical element, wherein a second prism portion comprising a plurality of second triangular prisms arranged along the arrangement direction of the plurality of first triangular prisms is provided on the emission surface.
  5. 　請求項４記載の光学素子において、
    　前記第２の三角プリズム部の底角θ２が５０度以上９０度未満であり、かつ、上記複数の第２の三角プリズムの隣り合う稜部間の間隔Ｐ２が、上記第２の三角プリズムの底面から上記第２の三角プリズムの稜部までの高さをＨ２とした場合、
    　（２×Ｈ２／ｔａｎθ２）≦Ｐ２＜（２０×Ｈ２／ｔａｎθ２）
    であることを特徴とする光学素子。     The optical element according to claim 4.
    The base angle θ2 of the second triangular prism portion is not less than 50 degrees and less than 90 degrees, and the interval P2 between adjacent ridge portions of the plurality of second triangular prisms is the bottom surface of the second triangular prism. When the height from the second triangular prism to the ridge is H2,
    (2 × H2 / tan θ2) ≦ P2 <(20 × H2 / tan θ2)
    An optical element characterized by the above.
  6. 　三角柱を呈する導光部を有し、
    　上記導光部の３つの側面のうち、１つの側面を光が入射する入射面とし、他の１つの側面を上記入射した光を全反射する全反射面とし、残りの１つの側面を上記全反射した光を外部へ出射する出射面とし、
    上記入射面には、上記全反射面を含む平面と上記出射面を含む平面とに交差する方向に稜線方向を向けた稜部を有する複数の第１の三角プリズムからなる第１のプリズム部が設けられる光学素子を備え、
    　上記入射面に光を入射させる複数の光源が、上記複数の第１の三角プリズムの配置方向に配置されている、
    ことを特徴とする発光装置。     Having a light guide that presents a triangular prism;
    Of the three side surfaces of the light guide unit, one side surface is an incident surface on which light is incident, the other one side surface is a total reflection surface that totally reflects the incident light, and the remaining one side surface is the entire surface. Let the reflected light be an exit surface that exits to the outside,
    The incident surface includes a first prism portion including a plurality of first triangular prisms having a ridge portion whose ridge line direction is directed in a direction intersecting the plane including the total reflection surface and the plane including the emission surface. Comprising an optical element provided;
    A plurality of light sources that cause light to enter the incident surface are arranged in an arrangement direction of the plurality of first triangular prisms,
    A light emitting device characterized by that.
  7. 　請求項６記載の発光装置において、
    　前記入射面の前記光源と対向しない部分には、前記第１のプリズム部が設けられない部分が存在することを特徴とする発光装置。     The light-emitting device according to claim 6.
    The light emitting device according to claim 1, wherein a portion of the incident surface that does not face the light source includes a portion where the first prism portion is not provided.
  8. 　請求項６記載の発光装置において、
    　前記複数の光源の発光色が異なることを特徴とする発光装置。     The light-emitting device according to claim 6.
    A light emitting device characterized in that light emission colors of the plurality of light sources are different.
  9. 　請求項６記載の発光装置において、
    　上記光学素子は、入射した光を多重散乱させる光散乱粒子を含有し、
    　上記光散乱粒子は、粒径が２μｍ～９μｍの透光性のシリコーン粒子であり、
    　上記光散乱粒子による散乱係数に相当する散乱パラメータである濁度をτとした場合、τ＞０．０１であることを特徴とする発光装置。     The light-emitting device according to claim 6.
    The optical element contains light scattering particles that multiple-scatter incident light,
    The light scattering particles are translucent silicone particles having a particle size of 2 μm to 9 μm,
    A light-emitting device, wherein τ> 0.01 when turbidity which is a scattering parameter corresponding to a scattering coefficient by the light scattering particles is τ.
  10. 　請求項６記載の発光装置において、
    　前記第１の三角プリズムの底角θ１が２０度以上７０度以下であり、かつ、前記複数の第１の三角プリズムの隣り合う稜部間の間隔Ｐ１が、前記第１の三角プリズムの底面から前記稜部までの高さをＨ１とした場合、
    　（２×Ｈ１／ｔａｎθ１）≦Ｐ１＜（１０×Ｈ１／ｔａｎθ１）
    であることを特徴とする発光装置。     The light-emitting device according to claim 6.
    The base angle θ1 of the first triangular prism is not less than 20 degrees and not more than 70 degrees, and the interval P1 between adjacent ridges of the plurality of first triangular prisms is from the bottom surface of the first triangular prism. When the height to the ridge is H1,
    (2 × H1 / tan θ1) ≦ P1 <(10 × H1 / tan θ1)
    A light emitting device characterized by the above.
  11. 　請求項６記載の発光装置において、
    　前記光散乱粒子は、粒径が２μｍ～９μｍの透光性のシリコーン粒子であり、
    　前記光学素子は、前記光散乱粒子による散乱係数に相当する散乱パラメータである濁度をτとした場合、τ＞０．０１であることを特徴とする発光装置。     The light-emitting device according to claim 6.
    The light scattering particles are translucent silicone particles having a particle size of 2 μm to 9 μm,
    The optical element is characterized in that τ> 0.01 when turbidity, which is a scattering parameter corresponding to a scattering coefficient by the light scattering particles, is τ.
  12. 　請求項６記載の発光装置において、
    　前記出射面には前記複数の第１の三角プリズムの配置方向に沿って配置される複数の第２の三角プリズムからなる第２のプリズム部が設けられていることを特徴とする発光装置。     The light-emitting device according to claim 6.
    2. A light emitting device according to claim 1, wherein a second prism portion comprising a plurality of second triangular prisms arranged along the arrangement direction of the plurality of first triangular prisms is provided on the emission surface.
  13. 　請求項１２記載の発光装置において、
    　前記第２の三角プリズム部の底角θ２が５０度以上９０度未満であり、かつ、上記複数の第２の三角プリズムの隣り合う稜部間の間隔Ｐ２が、上記第２の三角プリズムの底面から上記第２の三角プリズムの稜部までの高さをＨ２とした場合、
    　（２×Ｈ２／ｔａｎθ２）≦Ｐ２＜（２０×Ｈ２／ｔａｎθ２）
    であることを特徴とする発光装置。     The light-emitting device according to claim 12.
    The base angle θ2 of the second triangular prism portion is not less than 50 degrees and less than 90 degrees, and the interval P2 between adjacent ridge portions of the plurality of second triangular prisms is the bottom surface of the second triangular prism. When the height from the second triangular prism to the ridge is H2,
    (2 × H2 / tan θ2) ≦ P2 <(20 × H2 / tan θ2)
    A light emitting device characterized by the above.
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