WO2019187462A1 - Dispositif d'éclairage de forme plane - Google Patents

Dispositif d'éclairage de forme plane Download PDF

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Publication number
WO2019187462A1
WO2019187462A1 PCT/JP2018/048584 JP2018048584W WO2019187462A1 WO 2019187462 A1 WO2019187462 A1 WO 2019187462A1 JP 2018048584 W JP2018048584 W JP 2018048584W WO 2019187462 A1 WO2019187462 A1 WO 2019187462A1
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WO
WIPO (PCT)
Prior art keywords
lens
sheet
illumination device
optical element
planar illumination
Prior art date
Application number
PCT/JP2018/048584
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English (en)
Japanese (ja)
Inventor
英 椋本
Original Assignee
ミネベアミツミ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ミネベアミツミ株式会社 filed Critical ミネベアミツミ株式会社
Priority to JP2020509673A priority Critical patent/JP6785397B2/ja
Priority to TW108103475A priority patent/TW201942653A/zh
Publication of WO2019187462A1 publication Critical patent/WO2019187462A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S2/00—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/02—Simple or compound lenses with non-spherical faces
    • G02B3/08—Simple or compound lenses with non-spherical faces with discontinuous faces, e.g. Fresnel lens
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements

Definitions

  • the present invention relates to a planar illumination device.
  • planar illumination device that illuminates the display panel of a liquid crystal display device from the back side.
  • the planar illumination device is roughly classified into an edge light type and a direct type.
  • planar illumination device there is a planar illumination device corresponding to so-called local dimming (area light emission) that can adjust the luminance for each region of the light emitting surface by controlling the light quantity of each light source.
  • local dimming area light emission
  • a direct-type planar illumination device that supports local dimming (area light emission) is equipped with a lens that diffuses the light emitted from the light source, and the light from the light source is spread and emitted to make the luminance uniform in each region. can do.
  • the number of light sources arranged on the substrate has increased, and as the number of light sources increases, there is a positional shift between the lens and the light source arranged directly above each light source. As a result, the luminance of the light emitting surface may be uneven.
  • the present invention has been made in view of the above, and an object of the present invention is to provide a planar illumination device capable of making the luminance of the light emitting surface uniform.
  • a planar illumination device includes a substrate on which a plurality of light sources are arranged, and a circular bottom surface on an incident surface facing the plurality of light sources.
  • a plurality of optical elements having portions that taper from the tip toward the tip.
  • the luminance of the light emitting surface can be made uniform.
  • FIG. 1 is a top view illustrating an example of the appearance of the planar lighting device according to the embodiment.
  • FIG. 2A is an exploded perspective view of the planar lighting device according to the embodiment.
  • FIG. 2B is a perspective view of a lens according to the embodiment.
  • FIG. 3A is a top view illustrating an arrangement example of light sources according to the embodiment.
  • FIG. 3B is a top view showing another arrangement example of the light sources according to the embodiment.
  • FIG. 4 is a schematic cross-sectional view taken along the line AA shown in FIG.
  • FIG. 5 is an explanatory diagram of the positional relationship between the diffusion plate, the lens, and the light source.
  • FIG. 6 is an explanatory diagram illustrating the shape of the conical optical element according to the embodiment.
  • FIG. 7A is a top view illustrating an arrangement example of the conical optical elements according to the embodiment.
  • FIG. 7B is a top view illustrating another arrangement example of the conical optical element according to the embodiment.
  • FIG. 8 is an explanatory diagram for explaining that the luminance distribution on the exit surface is a hexagonal shape in the lens according to the embodiment.
  • FIG. 9 is a schematic cross-sectional view of a planar illumination device according to Modification 1 of the embodiment.
  • FIG. 10 is an explanatory diagram illustrating an arrangement of the optical sheets according to the second modification of the embodiment.
  • FIG. 11 is a diagram (part 1) illustrating a comparison result of luminance distributions depending on the presence or absence of the conical optical element according to the embodiment.
  • FIG. 1 is a diagram (part 1) illustrating a comparison result of luminance distributions depending on the presence or absence of the conical optical element according to the embodiment.
  • FIG. 12 is a diagram (part 2) illustrating a comparison result of luminance distributions with and without the conical optical element according to the embodiment.
  • FIG. 13 is a diagram showing a comparison result of luminance distributions due to the angle difference of the optical element.
  • FIG. 14 is a diagram illustrating a comparison result of luminance distributions due to a difference in diameter of the optical element.
  • FIG. 15 is a diagram illustrating a comparison result of the luminance distribution due to the positional deviation of the lens according to the embodiment.
  • FIG. 16 is a diagram illustrating a comparison result of luminance distributions depending on the presence / absence of dots according to the embodiment.
  • FIG. 17A is a top view of a lens according to a modification.
  • FIG. 17B is a sectional view taken along line BB in FIG.
  • FIG. 18A is a diagram illustrating a tip shape of an optical element according to a modification.
  • FIG. 18B is a diagram illustrating a tip shape of an optical element according to a modification.
  • FIG. 18C is a diagram illustrating a tip shape of an optical element according to a modification.
  • FIG. 18D is a diagram illustrating a tip shape of an optical element according to a modification.
  • FIG. 19 is a cross-sectional view of a planar illumination device according to a modification.
  • FIG. 20A is a diagram illustrating a configuration of an optical sheet according to a modification.
  • FIG. 20B is a diagram illustrating a configuration of an optical sheet according to a modification.
  • FIG. 20C is a diagram illustrating a configuration of an optical sheet according to a modification.
  • FIG. 21 is a diagram illustrating light distribution characteristics when the optical sheet according to the modification is provided.
  • FIG. 22A is a side view of a lens according to a modification.
  • FIG. 1 is a top view illustrating an example of the appearance of the planar lighting device according to the embodiment.
  • FIG. 2A is an exploded perspective view of the planar lighting device according to the embodiment.
  • FIG. 2B is a perspective view of a lens according to the embodiment.
  • the planar illumination device 1 is a direct-type planar illumination device and is used as a backlight of various liquid crystal display devices.
  • a liquid crystal display device is, for example, an electronic speedometer of a vehicle, but is not limited thereto.
  • FIG. 1 the Z axis with the upper frame 11 side of the planar illumination device 1 as the positive direction and the width direction (longitudinal direction) of the planar illumination device 1 are shown.
  • Such an orthogonal coordinate system may be shown in other drawings used in the following description.
  • the planar illumination device 1 according to the embodiment emits light from an emission region surrounded by the upper frame 11.
  • a power supply wiring, a signal wiring, and the like are connected to the connector C shown in FIG. That is, the planar lighting device 1 according to the embodiment is supplied with power and signals through the connector C.
  • the planar lighting device 1 includes a lower frame 12, a substrate 2, a reflector 3, a lens (lens sheet) 4, a spacer 5, and a diffusion plate 6.
  • the optical sheet 70 including the first sheet 71 and the second sheet 72 and the upper frame 11 are provided.
  • FIG. 3A is a top view illustrating an arrangement example of the light sources 20 according to the embodiment.
  • the plurality of light sources 20 are arranged on the substrate 2 in a staggered arrangement (arranged in a hexagonal lattice pattern).
  • one light source 20 is arranged at a predetermined interval so as to be surrounded by six light sources 20.
  • the light source 20 is a point light source, and uses, for example, an LED (Light Emitting Diode).
  • an LED Light Emitting Diode
  • the light source 20 for example, a package type LED or a chip type LED can be used, but it is not limited to this.
  • a chip-type LED is used as the light source 20, it may be combined with a wavelength conversion member such as a phosphor sheet.
  • the plurality of light sources 20 are arranged in a staggered arrangement.
  • the arrangement is not limited to this, and as shown in FIG. 3B, the arrangement of the plurality of light sources 20 is a rectangular arrangement (matrix arrangement or lattice arrangement). Array).
  • FIG. 3B is a top view illustrating another arrangement example of the light source 20 according to the embodiment.
  • so-called local dimming area light emission
  • so-called local dimming area light emission
  • a general direct type planar illumination device when a plurality of light sources are arranged on a substrate as described above and a lens is arranged directly above each light source, the alignment between the light source and the lens can be achieved. It can be difficult. For example, when a large number of light sources are arranged on the substrate, it becomes difficult to align the light source and the lens.
  • the incident surface 41 a facing the light source 20 is smaller than the pitch of the light sources 20 with respect to the substrate 2 on which a plurality of light sources are arranged.
  • the lens 4 having a plurality of conical optical elements 40 arranged at a pitch was integrally covered.
  • planar illumination device 1 that can make the luminance of the light emitting surface uniform according to the present embodiment will be described more specifically with reference to FIGS.
  • FIG. 4 is a schematic cross-sectional view along the line AA shown in FIG. Specifically, FIG. 4 is a schematic cross-sectional view illustrating the internal configuration of the planar illumination device 1 according to the embodiment.
  • the planar illumination device 1 according to the embodiment includes a frame 10, a substrate 2, a light source 20, a reflection plate 3, a lens 4, a spacer 5, a diffusion plate 6, and an optical sheet. 70.
  • the frame 10 is a sheet metal frame made of, for example, stainless steel having high rigidity, and accommodates each member of the planar lighting device 1.
  • the frame 10 includes an upper frame 11 and a lower frame 12, for example.
  • the upper frame 11 is disposed on the upper surface side of the lower frame 12.
  • the upper frame 11 includes a rectangular top plate 11a having an opening at the center, and a side wall 11b extending along the outer surface of the lower frame 12 from the periphery of the top plate 11a.
  • the lower frame 12 has a rectangular bottom portion 12a and side walls 12b extending along the inner surface of the upper frame 11 from the periphery of the bottom portion 12a.
  • the substrate 2 is made of, for example, epoxy resin or PI (polyimide), and a plurality of light sources 20 are mounted (see FIG. 3).
  • the light source 20 is disposed on the substrate 2 so that the optical axis is substantially perpendicular to the lens 4.
  • the reflector 3 is disposed on the substrate 2, and a hole in which the light source 20 is disposed is formed at a position corresponding to each light source 20 mounted on the substrate 2.
  • the reflecting plate 3 is made of, for example, a white resin.
  • the reflector 3 reflects the light reflected by the lens 4 toward the reflector 3 again toward the lens 4. Thereby, the emission efficiency can be improved.
  • the lens 4 performs light distribution control of the light emitted from the light source 20. Specifically, the light emitted from the light source 20 is refracted and spreads by the lens 4 and emitted.
  • the lens 4 is a plate-like member made of a material such as PMMA (polymethyl methacrylate), polycarbonate, PET (polyethylene terephthalate), or silicone, and a plurality of light sources 20 arranged on the substrate 2 are integrated. Cover.
  • the lenses 4 are arranged in a staggered arrangement on the incident surface 41 a facing the plurality of light sources 20 mounted on the substrate 2, the emission surface 41 b that is the back surface of the incident surface 41 a, and the incident surface 41 a.
  • a plurality of conical optical elements 40 projecting toward the center.
  • the spacer 5 is arranged between the lens 4 and the diffusion plate 6 and keeps the distance between the lens 4 and the diffusion plate 6 constant.
  • the material of the spacer 5 is not particularly limited.
  • the spacer 5 may be formed of a white resin and may have a function of reflecting light emitted from the lens 4.
  • the spacer 5 presses the diffusion plate 6 from the lower surface side along the longitudinal direction (X axis) of the planar illumination device 1 and presses the lens 4 from the upper surface side along the longitudinal direction.
  • the spacer 5 does not necessarily need to hold
  • the diffusion plate 6 is made of, for example, a material such as resin and has a function of diffusing the light of the light source 20 emitted from the lens 4. That is, the light emitted from the lens 4 is diffused by the diffusion plate 6 and guided to the optical sheet 70.
  • FIG. 5 is an explanatory diagram of a positional relationship among the diffusion plate 6, the lens 4, and the light source 20.
  • the lens 4 is disposed between the diffusion plate 6 and the light source 20. Further, the lens 4 and the light source 20 are arranged apart from each other. In addition, the lens 4 and the diffusion plate 6 are spaced apart. That is, the lens 4 is arranged separately from the diffusion plate 6 and the light source 20.
  • the lens 4 has a distance Gb from the optical element 40 to the diffusion plate 6 rather than a distance Ga from the optical element 40 to the light source 20 in a state where the distance between the light source 20 and the diffusion plate 6 is set to a predetermined value. It is arranged at a position where the direction becomes longer. Specifically, the distance from the incident surface 41a (optical element 40) of the lens 4 to the incident surface 6a of the diffusion plate 6 is larger than the distance Ga from the upper surface 20a of the light source 20 to the incident surface 41a (optical element 40) of the lens 4.
  • the distance Gb is long.
  • the distance Gb from the incident surface 41a to the incident surface 6a of the diffusion plate 6 can be increased.
  • the optical path length from the lens 4 to the diffusion plate 6 can be increased, so that the light refracted and emitted from the lens 4 further spreads and enters the diffusion plate 6.
  • the lens 4 is arranged at a position where the distance Gb is longer than the distance Ga in a state where the distance between the light source 20 and the diffusion plate 6 is set to a predetermined value, thereby spreading the light of the lens 4.
  • the effect is effectively exhibited and the luminance can be made uniform.
  • the distance Ga and the distance Gb are calculated based on the incident surface 41 a of the lens 4, that is, the bottom surface 43 a (see FIG. 6) of the optical element 40, but the distance is based on the tip of the optical element 40. Ga and distance Gb may be calculated.
  • the optical sheet 70 performs optical adjustments such as homogenization and light distribution control on the light emitted from the diffusion plate 6 and emits the light that has been optically adjusted.
  • optical adjustments such as homogenization and light distribution control on the light emitted from the diffusion plate 6 and emits the light that has been optically adjusted.
  • FIGS. 2A and 4 a case where the optical sheet 70 includes two sheets of a first sheet 71 and a second sheet 72 is illustrated.
  • the first sheet 71 is a prism sheet (for example, 3M Brightness Enhancement Film), and the second sheet 72 is a reflective polarizing sheet (for example, 3M Dual Brightness Enhancement Film). It can be arbitrarily changed according to the light emission mode required for the illuminating device 1.
  • the optical sheet 70 is fixed to the output surface of the diffusion plate 6 by an adhesive member such as an adhesive or a double-sided tape.
  • An elastic member having elasticity such as rubber or sponge may be provided between the top plate 11a of the upper frame 11 and the optical sheet 70. Such an elastic member presses the diffusion plate 6 through the optical sheet 70 from the top plate 11 a side of the upper frame 11. Thereby, when a vibration arises in the planar illumination device 1, the elastic member absorbs the vibration.
  • FIG. 6 is an explanatory diagram showing the shape of the conical optical element 40 according to the embodiment. Further, FIG. 6 shows a top view shape of the light source 20 in order to compare the sizes of the optical elements 40.
  • the optical element 40 is, for example, a conical prism.
  • the optical element 40 has a conical bottom surface 43a and a conical inclined surface 43b (an example of an inclined surface intersecting the bottom surface 43a), and extends from the bottom surface 43a toward the tip that is on the negative side of the Z axis. And has a tapered part.
  • the optical element 40 has a portion where the area of a cross section substantially parallel to the bottom surface 43a becomes smaller toward the tip.
  • the angle ⁇ between the conical bottom surface 43a and the conical inclined surface 43b is, for example, not less than 44 ° and not more than 58 °.
  • the angle ⁇ between the conical bottom surface 43a and the conical inclined surface 43b is preferably 44 ° or more and 55 ° or less, for example. More preferably, in the optical element 40, the angle ⁇ between the conical bottom surface 43a and the conical inclined surface 43b is preferably 50 °, for example, in order to improve the uniformity of the luminance of the light emitting surface. .
  • the diameter D of the conical bottom surface 43a is, for example, 0.1 mm or more and 0.3 mm or less
  • the conical height H is, for example, 0.05 mm or more and 0.15 mm or less. More preferably, in the optical element 40, in order to improve the uniformity of the luminance of the light emitting surface, the diameter D of the conical bottom 43a is 0.2 mm, for example, and the conical height H is 0. It is preferably 1 mm.
  • the diameter D of the optical element 40 is shorter than the length D20 between the diagonals of the light source 20 which is, for example, rectangular.
  • the diameter D of the optical element 40 is preferably 1 ⁇ 2 or less of the length D20 of the light source 20.
  • the diameter D of the optical element 40 is preferably 1 ⁇ 2 or less of the maximum distance of the light source 20 in the top view shape.
  • the diameter D of the optical element 40 is more preferably 1/10 or less of the maximum distance of the light source 20 in the top view shape. That is, since the optical element 40 is smaller than the light source 20, even if a positional deviation occurs between the light source 20 and the optical element 40, the positional deviation can be substantially invalidated. It can be prevented from decreasing.
  • the diameter D of the optical element 40 can be replaced with the pitch of the optical element 40.
  • the top view shape of the light source 20 is not limited to a rectangular shape, and may be another shape such as a circle or a polygon.
  • the diameter D of the optical element 40 is preferably 1 ⁇ 2 or less of the diameter of the light source 20. That is, the diameter D of the optical element 40 is preferably less than or equal to 1 ⁇ 2 of the maximum distance of the light source 20 in the top view shape.
  • the diameter D and the height H of the optical element 40 shown in FIG. 6 are examples, and all of the plurality of optical elements 40 do not have to have the same diameter D and height H uniformly. That is, the plurality of optical elements 40 may have different diameters D and heights H, or may be the same.
  • the optical element 40 is not limited to a convex portion, and may be a concave portion.
  • the tip shape of the optical element 40 is not limited to a conical shape, and may be an arbitrary shape such as an arc shape. That is, the optical element 40 can adopt any shape as long as it has a portion that tapers from the circular bottom surface 43a toward the tip. Further, the optical element 40 does not have to be an accurate cone shape. That is, the conical optical element 40 may be regarded as a conical shape even when the tip has a slight arc shape due to a manufacturing error or the like.
  • the optical element 40 may include a convex portion and a concave portion. That is, the optical element 40 may be formed by mixing a convex portion protruding toward the light source 20 and a concave portion recessed in a direction away from the light source 20.
  • FIG. 7A is a top view illustrating an arrangement example of the conical optical element 40 according to the embodiment.
  • FIG. 7A shows a part of the lens 4 for convenience.
  • a large number of conical optical elements 40 are arranged on the incident surface 41a of the lens 4 in a staggered arrangement (arranged in a hexagonal lattice). That is, in the example shown in FIG. 7A, the optical elements 40 are arranged such that a pair of opposing two sides of the hexagonal lattice 42 a are parallel to the longitudinal direction of the lens 4. Note that the arrangement is not limited to that shown in FIG. 7A, and the hexagonal lattice 42a may be rotated 90 degrees. Thus, by rotating the direction of the hexagonal lattice 42a by 90 °, the luminance distribution on the light emitting surface can be lengthened in a predetermined direction.
  • FIG. 7B is a top view illustrating another arrangement example of the conical optical element 40 according to the embodiment.
  • FIG. 7B also shows a part of the lens 4 for convenience.
  • the optical elements 40 are arranged so that two sets of two sides facing each other of the hexagonal lattice 42 b are parallel to the lateral direction of the lens 4.
  • the staggered arrangement indicates that the optical elements 40 are arranged at the apexes and the centers of the hexagons, and the hexagonal arrangements are continuously arranged. That is, the plurality of conical optical elements 40 are arranged in a hexagonal shape within the incident surface 41 a of the lens 4. In this example, one optical element 40 is surrounded by six optical elements 40 and arranged in a hexagonal close-packed arrangement so as to be in contact with the six optical elements 40. Alternatively, a space (flat portion) may be provided between the adjacent optical elements 40 and arranged in a hexagonal close-packed arrangement.
  • the lens 4 arranges the plurality of conical optical elements 40 in a staggered arrangement on the incident surface 41 a facing the plurality of light sources 20, and thereby the luminance of the emitted light from each light source 20.
  • the distribution can be hexagonal.
  • the shape of the light emitting region corresponding to each light source 20 can be a hexagonal shape.
  • the luminance distribution of the light emitted from each light source 20 has a hexagonal shape (polygonal shape with straight sides), and thus the interval between the light emitting regions is narrowed. High-density local dimming (area light emission) is possible.
  • the planar illumination device 1 according to the present embodiment can control the contrast more finely at the time of local dimming (area light emission) while making the luminance of the light emitting surface uniform.
  • FIG. 8 is an explanatory diagram for explaining that the luminance distribution on the exit surface 41b is hexagonal in the lens 4 according to the embodiment. Specifically, FIG. 8 shows diffusion of the optical element 40 in the range of azimuth angles of 0 ° to 360 ° of incident light emitted from the light source 20.
  • each axis has its own center.
  • the number of overlapping optical elements 40 is greater than the other axes.
  • the “axis in the direction of 0 ° -180 °”, the “axis in the direction of 60 ° -240 °”, and the “axis in the direction of 120 ° -300 °” in which the number of the optical elements 40 is maximum that is,
  • the luminance on these three axes shifted by 60 ° is the largest.
  • the luminance on the three axes shifted by 30 ° from these three axes is the next highest. Therefore, the luminance distribution on the exit surface 41b of the lens 4 has a hexagonal shape.
  • the planar illumination device 1 includes the substrate 2 and the lens 4.
  • a plurality of light sources 20 are arranged on the substrate 2.
  • a plurality of optical elements 40 having portions that taper from the circular bottom surface 43 a toward the tip are arranged in a staggered arrangement on the incident surface 41 a facing the light sources 20.
  • the plurality of light sources 20 are integrally covered with the lenses 4 in which the fine conical optical elements 40 are arranged at a pitch smaller than the pitch of the light sources 20, thereby aligning the light sources 20 and the lenses 4.
  • the luminance of the light emitting surface can be made uniform without alignment.
  • the planar illumination device 1 includes the lens 4 that arranges the plurality of conical optical elements 40 in a staggered arrangement on the incident surface 41 a facing the light source 20. It is possible to make the luminance distribution of incident light hexagonal. In other words, on the light emitting surface, the shape of the light emitting region corresponding to each light source 20 can be a hexagonal shape.
  • the luminance distribution of the light emitted from each light source 20 has a hexagonal shape (polygonal shape with straight sides), and thus the interval between the light emitting regions is narrowed. High-density local dimming (area light emission) is possible.
  • the planar illumination device 1 according to the present embodiment can control the contrast more finely at the time of local dimming (area light emission) while making the luminance of the light emitting surface uniform.
  • the planar illumination device 1 is a conical prism in which a plurality of optical elements 40 arranged on the lens 4 protrude toward the plurality of light sources 20.
  • the light emitted from the plurality of light sources 20 is spread by the refraction action of the prism and is emitted from the emission surface 41 b of the lens 4. This prevents the portion directly above the light source 20 from becoming too bright, and even in the case of local dimming (area light emission) or when all the light sources 20 are turned on (increase the luminance), the luminance of the light emitting surface is made uniform. Can be planned.
  • the angle ⁇ of the conical optical element 40 is set to 44 ° or more and 58 ° or less, so that the light emitted from the light source 20 is totally reflected even when it hits the optical element 40. Without being incident on the lens 4, the light emitted from the lens 4 is diffused outward, so that the luminance of the light emitting surface becomes uniform.
  • ⁇ Modification 1> a plurality of conical optical elements 40 that are arranged in a staggered arrangement on the incident surface 41 a of the lens 4 and protrude toward the light source 20 are provided. You may further have the some diffusion element 44 which protrudes from the surface 41b.
  • the diffusing element 44 is, for example, a dot protruding from the exit surface 41b of the lens 4, but is not limited to this.
  • FIG. 9 is a schematic cross-sectional view of the planar illumination device 1 according to the first modification of the embodiment. Components having the same functions as those shown in FIG. 4 are given the same reference numerals as those shown in FIG.
  • a plurality of diffusing elements 44 (dots) projecting from the exit surface 41b are uniformly provided on the exit surface 41b of the lens 4.
  • the planar illumination device 1 includes a plurality of conical optical elements 40 that are arranged in a staggered arrangement on the incident surface 41 a of the lens 4 and project toward the light source 20.
  • the plurality of diffusion elements 44 are provided uniformly on the emission surface 41b and project from the emission surface 41b.
  • planar illumination device 1 prevents the exit surface 41 of the lens 4 from being scratched directly by roughening the exit surface 41 of the lens 4 by the plurality of diffusion elements 44. be able to.
  • planar illumination device 1 allows light to enter the region immediately above the light source 20 by the diffusion effect by the plurality of diffusion elements 44, and to make the luminance of the light emitting surface more uniform. Become.
  • the configuration of the diffusing element 44 is not limited to this.
  • the surface of the emission surface 41b is It may be in a rough state.
  • the rough emitting surface 41b may be formed by sand blasting, or the lens 4 may be subjected to embossing and the embossing may be transferred to the emitting surface 41b.
  • the incident surface 41a may be in a rough state without being limited to the case where the light exit surface 41b is in a rough state.
  • the incident surface 41a is roughened, the entire incident surface 41a including the optical element 40 may be roughened, or only the optical element 40 of the incident surface 41a may be roughened.
  • the optical sheet 70 includes the first sheet 71 and the second sheet 72, the first sheet 71 is a prism sheet, and the second sheet 72 is a reflective polarizing sheet.
  • the present invention is not limited to this.
  • the first sheet 71 may be a prism sheet
  • the second sheet 72 may be a prism sheet.
  • the prism sheet of the first sheet 71 and the prism sheet of the second sheet 72 are arranged orthogonally.
  • FIG. 10 is an explanatory diagram illustrating a configuration of an optical sheet 70 according to Modification 2 of the embodiment.
  • an optical element 71a (hereinafter referred to as a first prism 71a) formed on the first sheet 71 and an optical element 72a (hereinafter referred to as a second prism 72a) formed on the second sheet 72.
  • the optical sheet 70 includes a first sheet 71 having a plurality of first prisms 71a extending in a longitudinal direction (X-axis direction) that is a first direction, and a second sheet orthogonal to the first direction.
  • the first prism 71a and the second prism 72a have, for example, a triangular shape in cross-sectional view.
  • the first prism 71a formed on the first sheet 71 and the second prism 72a formed on the second sheet 72 are arranged so as to be orthogonal to each other by 90 °.
  • first prism 71a formed on the first sheet 71 and the second prism 72a formed on the second sheet 72 are not limited to be disposed so as to be orthogonal to each other by 90 °. If the light distribution can be controlled, the first prism 71a formed on the first sheet 71 and the second prism 72a formed on the second sheet 72 are arranged at an angle of 90 ° or less. May be.
  • first prism 71a and the second prism 72a are not limited to be arranged to be orthogonal (intersect at 90 °), and an arbitrary intersection angle is set according to the required light distribution characteristic. Good.
  • the lens 4 is not limited to the above-described embodiment, and the lens 4 may be divided.
  • the plurality of light sources 20 are arranged so that gaps between the plurality of lenses 4 are not located immediately above the light source 20.
  • light can be guided directly above the gap by the refracting action of the optical element 40 of the lens 4, so that it is possible to prevent the luminance of the gap area from being lowered. That is, by using the lens 4 according to the embodiment, it is possible to prevent the gap between the lenses 4 from appearing as a dark portion, and thus it is possible to improve luminance uniformity.
  • FIG. 11 is a diagram (part 1) showing a comparison result of luminance distributions with and without the cone-shaped optical element 40 according to the embodiment
  • FIG. 12 is a comparison result of luminance distributions with and without the cone-shaped prism according to the embodiment.
  • FIG. 11 and FIG. 12 the brightness is shown in shades, and the darker the shade, the stronger the brightness (brighter).
  • the planar illumination device 1 As shown in FIG. 11, when the luminance distribution is compared between the planar illumination device including a lens on which the conical optical element 40 is not disposed and the planar illumination device 1 according to the embodiment, the planar illumination device 1. It can be seen that the brightness distribution between the light sources 20 is smoothly connected to obtain a clear hexagonal brightness distribution.
  • the luminance distribution of the light emitted from the light source 20 has a hexagonal shape, so that the luminance of the light emitting surface can be made uniform. It is also possible to control the contrast more finely during local dimming (area light emission).
  • the luminance distribution of the light emitted from the light source 20 can be made hexagonal by arranging a plurality of conical optical elements 40 in a staggered arrangement on the incident surface 41a facing the light source 20. .
  • FIG. 13 is a diagram showing a comparison result of luminance distributions due to a difference in the angle ⁇ of the optical element 40.
  • FIG. 13 shows the luminance distribution in the angle range where the angle ⁇ is 40 ° to 62 °, specifically, 40 °, 44 °, 50 °, 58 ° and 62 °.
  • FIG. 13 shows the luminance distribution when all nine light sources 20 arranged in a rectangular array are lit (when nine lamps are lit).
  • the luminance uniformity is highest when the angle ⁇ is 50 °.
  • the cases of 44 ° and 58 ° have the next highest luminance uniformity, and the cases of 40 ° and 62 ° have the lowest luminance uniformity.
  • the optical element 40 has higher luminance uniformity as the angle ⁇ is closer to 50 °. Also, if the angle ⁇ is in the range of 44 ° to 58 °, the light emitted from the light source 20 enters the optical element 40 of the lens 4 and is refracted and spreads out. That is, the angle ⁇ of the optical element 40 is preferably not less than 44 ° and not more than 58 °, more preferably 50 °. By designing in such a range of the angle ⁇ , it is possible to make the luminance uniform.
  • FIG. 14 is a diagram showing a comparison result of luminance distributions due to a difference in the diameter D of the optical element 40.
  • FIG. 15 is a diagram illustrating a comparison result of the luminance distribution due to the positional deviation of the lens 4 according to the embodiment.
  • FIG. 14 shows the luminance distribution when all nine light sources 20 arranged in a rectangular array are lit (when nine lamps are lit).
  • FIG. 15 shows a luminance distribution when one light source 20 is turned on (when one lamp is turned on).
  • 14 and 15 show the ratio of the diameter D of the optical element 40 to the maximum distance (length D20 between diagonals) of the light source 20 (LED).
  • “1/2” indicates that the diameter D of the optical element 40 is 1 ⁇ 2 of the length D20 of the light source 20 (see FIG. 6).
  • the brightness uniformity is highest in the case of “1/10”, and the brightness uniformity is high in the order of “1/2” and “4/5”. That is, the smaller the diameter D of the optical element 40, the higher the luminance uniformity. On the other hand, if “1 ⁇ 2”, luminance unevenness is not easily realized. That is, the diameter D of the optical element 40 is preferably 1 ⁇ 2 or less, more preferably 1/10 or less of the maximum distance of the light source 20 in the top view shape. By designing the diameter D of the optical element 40 as described above, the luminance can be made uniform.
  • the change in the luminance distribution is extremely small. Furthermore, the change of the luminance distribution is smaller in “1/10” than in “1/2”. That is, the diameter D of the optical element 40 is preferably 1 ⁇ 2 or less, more preferably 1/10 or less of the maximum distance of the light source 20 in the top view shape. In other words, since “1/2” and “1/10” can substantially invalidate the positional deviation between the light source 20 and the lens 4, the light source 20 and the lens are caused by, for example, vibration or thermal expansion (or contraction) of the lens 4. Even when the position is shifted from 4, the luminance can be made uniform.
  • the planar illumination device 1 including the lens 4 that does not have the diffusion element 44 on the exit surface 41 b and the planar illumination device 1 that includes the lens 4 that includes the diffusion element 44 on the exit surface 41 b
  • the brightness of the central portion of the planar illumination device 1 including the lens 4 having the diffusing element 44 on the emission surface 41b is brighter.
  • FIG. 17A is a top view of a lens 4 according to a modification.
  • FIG. 17B is a sectional view taken along line BB in FIG. 17A.
  • FIG. 17A shows a case where the plurality of light sources 20 are in a rectangular array.
  • the lens 4 has a leg 400 that protrudes toward the substrate 2 on the incident surface 41a.
  • the lens 4 is supported on the substrate 2 via the leg 400.
  • interval between the lens 4 and the light source 20 can be kept constant.
  • the leg 400 can keep the distance between the lens 4 and the light source 20 constant, which can contribute to uniform luminance.
  • the lens 4 may be fixed to the substrate 2 via the leg 400.
  • the legs 400 extend in a lattice shape (X-axis direction and Y-axis direction) and individually surround the plurality of light sources 20. Thereby, since it is possible to prevent the light from the adjacent light sources 20 from entering, it is possible to improve the contrast during local dimming (area light emission).
  • FIG. 17A and 17B show the case where the lens 4 and the leg portion 400 are integrally configured, the lens 4 and the leg portion 400 may be configured separately. Alternatively, the leg portion 400 may be integrated with the substrate 2.
  • the leg portion 400 may have a function as a reflecting portion by making the surface of the leg portion 400 rough.
  • FIG. 17A shows the case where the plurality of light sources 20 are in a lattice arrangement.
  • the leg portion 400 extends in a staggered arrangement so that the plurality of light sources 20 are arranged in a staggered arrangement. 20 are individually enclosed.
  • the optical element 40 has a conical shape (a shape with a sharp tip), but the tip of the optical element 40 may not have a sharp shape.
  • the tip shape of the optical element 40 may be a shape as shown in FIGS. 18A to 18D.
  • FIG. 18A to FIG. 18D are diagrams showing the tip shape of the optical element 40 according to the modification.
  • the tip shape of the optical element 40 may be an arc shape.
  • the tip shape of the optical element 40 may be a planar shape.
  • Such a planar shape may be, for example, the same circle as the bottom surface 43a of the optical element 40 or a polygon other than a circle.
  • the tip shape of the optical element 40 may be a recessed portion.
  • the optical element 40 may have an arc shape in which the inclined surface 43b is concave.
  • the inclined surface 43b may have a convex arc shape.
  • the tip shape of the optical element 40 shown in FIGS. 18A to 18D can be adopted. That is, the tip shape of the optical element 40 may be any shape as long as it has a portion that tapers from the bottom surface 43a toward the tip.
  • the optical sheet 70 is configured by the first sheet 71 and the second sheet 72, but the optical sheet 70 may be configured by three sheets. This point will be described with reference to FIGS.
  • FIG. 19 is a cross-sectional view of the planar lighting device 1 according to a modification.
  • 20A to 20C are diagrams illustrating a configuration of an optical sheet 70 according to a modification.
  • FIG. 21 is a diagram illustrating light distribution characteristics when the optical sheet 70 according to the modification is provided. Note that FIG. 21 shows the luminance of the emitted light in the polar coordinate system in which the declination is in the range of 0 ° to 80 °, and the darker the darker the stronger the luminance (brighter).
  • the optical sheet 70 is composed of, for example, three sheets. Specifically, the optical sheet 70 includes a first sheet 71, a second sheet 72, and a third sheet 73. Since the configuration of the first sheet 71 and the second sheet 72 is the same as that of the above-described embodiment, the description thereof is omitted.
  • the third sheet 73 is a sheet-like member disposed on the light emission direction side that is the Z-axis positive direction side of the second sheet 72.
  • ALCF Advanced Light Control Film
  • 3M It is a member in which a reflective polarizing sheet and a louver film are integrated.
  • the louver 73a of the third sheet 73 preferably has a light cutoff of 45 ° or less.
  • the third sheet 73 is disposed on the side farther from the lens 4 than the first sheet 71 and the second sheet 72.
  • the third sheet 73 is a member whose positional relationship is defined by the extending direction of the first prism 71a and the second prism 72a in the extending direction (third direction) of the louver 73a (optical element) of the louver film. is there.
  • the reflective polarizing sheet of the third sheet 73 may be in any extending direction regardless of the first prism 71a and the second prism 72a.
  • 20A to 20C show a positional relationship among the louver 73a, the first prism 71a, and the second prism 72a.
  • the first prism 71a extends in the Y-axis direction
  • the second prism 72a extends in the X-axis direction
  • the louver 73a extends in the X-axis direction.
  • the louver 73a is substantially orthogonal to the first prism 71a and substantially parallel to the second prism 72a.
  • the outgoing light having a declination angle of a predetermined angle (approximately 45 ° in FIG. 21) or more can be cut. it can. That is, the spread of the emitted light in the longitudinal direction and the short direction of the planar illumination device 1 can be suppressed. Therefore, for example, when the planar lighting device 1 is applied to the vehicle-mounted device, reflection on the windshield or the side window glass can be suppressed.
  • the second prism 72a may be rotated by a predetermined angle from the X-axis direction to the rotation direction. That is, as shown in FIG. 20B, the second prism 72a is deviated from the first prism 71a by substantially the same angle as the rotation angle. Further, the second prism 72a deviates from the louver 73a substantially parallel by the rotation angle.
  • the rotation angle is preferably ⁇ 20 ° or less.
  • the first prism 71a and the second prism 72a may be rotated by approximately 45 ° while maintaining an orthogonal relationship with each other.
  • the first prism 71a is rotated by approximately 45 ° in the rotation direction (for example, counterclockwise) from the Y-axis direction.
  • the second prism 72a is rotated by approximately 45 ° in the rotation direction (for example, counterclockwise) from the X-axis direction.
  • the louver 73a extends in the X-axis direction. That is, the louver 73a is disposed with a shift of about 45 ° with respect to the first prism 71a and the second prism 72a.
  • the louver 73a is disposed with a shift of about 45 ° with respect to the first prism 71a and the second prism 72a.
  • the rotation angle can correspond to ⁇ 60 ° or less.
  • the louver 73a may be rotated from the X-axis direction by a predetermined angle in the rotation direction.
  • the rotation angle of the louver 73a is preferably ⁇ 10 ° or less.
  • the third sheet 73 has been described in the case where the reflective polarizing sheet and the louver film are integrally configured.
  • the third sheet 73 may include the reflective polarizing sheet and the louver film separately. .
  • FIG. 22A is a side view of the lens 4 according to a modification.
  • FIG. 22B is an enlarged view of the optical element 40 according to a modification. 22A and 22B, a case where the optical element 40 has a convex conical shape will be described. 22B shows an enlarged view of a region surrounded by a broken line shown in FIG. 22A.
  • the lens 4 has a curved shape bent in the Z-axis direction. Specifically, the lens 4 has a curved surface shape in which the incident surface 41a is convex and the output surface 41b is concave.
  • the radius (R) of the lens 4 having a curved surface shape can be set in a range where the angle ⁇ (see FIG. 6) of the optical element 40 is approximately 44 ° or more and 58 ° or less.
  • the optical element 40 when the lens 4 has a curved surface shape, the optical element 40 preferably has an asymmetrical cone shape in a side view. Specifically, the optical element 40 has a shape facing the inner side (center side of the lens 4) than a virtual vertical line VL that is parallel to the Z-axis direction. More specifically, in the optical element 40, the apex of the cone is positioned inside the vertical line VL. In other words, since the optical element 40 faces inward from the vertical line VL, the optical element 40 can be prevented from being caught by the mold when the mold is pulled out in the negative Z-axis direction. Therefore, when the lens 4 has a curved shape, the workability when removing the optical element 40 from the mold can be improved.
  • the lens 4 has a curved surface shape convex toward the Z-axis negative direction, but may have a curved surface shape convex toward the Z-axis positive direction. In such a case, it is preferable that the optical element 40 has a shape facing the outer side (the peripheral end side of the lens 4) than the vertical line VL.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Planar Illumination Modules (AREA)

Abstract

La présente invention porte, selon un mode de réalisation, sur un dispositif d'éclairage de forme plane (1) qui comporte : un substrat (2) sur lequel une pluralité de sources de lumière (20) sont disposées ; et une lentille (4) dans laquelle, sur une surface incidente (41a) faisant face à la pluralité de sources de lumière, une pluralité d'éléments optiques (40), dont chacun comporte une section de pointe effilée à partir d'une surface inférieure circulaire vers une extrémité distale, sont disposés selon une forme en zigzag.
PCT/JP2018/048584 2018-03-30 2018-12-28 Dispositif d'éclairage de forme plane WO2019187462A1 (fr)

Priority Applications (2)

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JP2020509673A JP6785397B2 (ja) 2018-03-30 2018-12-28 面状照明装置
TW108103475A TW201942653A (zh) 2018-03-30 2019-01-30 面狀照明裝置

Applications Claiming Priority (6)

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JP2018068188 2018-03-30
JP2018-068188 2018-03-30
JP2018119165 2018-06-22
JP2018-119165 2018-06-22
JP2018-202205 2018-10-26
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4215801A1 (fr) * 2022-01-24 2023-07-26 Analytik Jena US LLC Dispositif de conversion de lumière à uniformité élevée

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004355939A (ja) * 2003-05-29 2004-12-16 Harison Toshiba Lighting Corp バックライトユニット
JP2005285702A (ja) * 2004-03-31 2005-10-13 Citizen Watch Co Ltd 導光部材及びそれを用いた照明装置
JP2009122637A (ja) * 2007-11-12 2009-06-04 Samsung Electronics Co Ltd 導光板およびこれを有する表示装置
JP2010040192A (ja) * 2008-07-31 2010-02-18 Toshiba Corp バックライトユニットおよびこれを備えた液晶表示装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004355939A (ja) * 2003-05-29 2004-12-16 Harison Toshiba Lighting Corp バックライトユニット
JP2005285702A (ja) * 2004-03-31 2005-10-13 Citizen Watch Co Ltd 導光部材及びそれを用いた照明装置
JP2009122637A (ja) * 2007-11-12 2009-06-04 Samsung Electronics Co Ltd 導光板およびこれを有する表示装置
JP2010040192A (ja) * 2008-07-31 2010-02-18 Toshiba Corp バックライトユニットおよびこれを備えた液晶表示装置

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4215801A1 (fr) * 2022-01-24 2023-07-26 Analytik Jena US LLC Dispositif de conversion de lumière à uniformité élevée

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JP6785397B2 (ja) 2020-11-25
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