JP2011054446A - Illumination body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination body which scarcely generates the unevenness of luminance and reduces a thickness, and can easily be adapted to an existing product. <P>SOLUTION: The illumination body L includes a light reflection member A, a light transmissive light diffusion sheet B, and a light source C. Recessed parts 2, 2 are connected by a connection part 24 formed on a reflection surface 24a of which the front surface is flat. When a light radiation angle of the light source C is θ, an angle formed of a straight line passing through the light source C and orthogonal to the light transmissive light diffusion sheet B and a straight line passing through the light source C and an opening end of the recessed part 2 is α, and an angle formed of a straight line passing a point, where a straight line passing the center in a width direction of the connection part 24 connecting the recessed parts 2, 2 and orthogonal to the light transmissive light diffusion sheet B intersects with the light transmissive light diffusion sheet B, and the light source C, and a straight line passing through the light source C and orthogonal to the light transmissive light diffusion sheet B is β, a relationship of an expression 1 β≤α<θ is satisfied. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an illuminating body.

  Conventionally, fluorescent lamps and cold cathode fluorescent lamps (CCFLs) that have a relatively long light source lifetime have been used as light sources for electrical signs, interior-lit signs, liquid crystal display backlights, and lighting devices. in use.

  However, fluorescent tube lamps are straight tube type and easy to break, and cold cathode fluorescent tubes use mercury that is used at high voltage, so there are problems in environmental pollution due to illegal dumping and safety to human body. Yes.

  Therefore, a light emitting diode (LED) that is easy for the environment, has a long life, and is excellent in energy saving is promising as a light source to replace a fluorescent tube lamp and a cold cathode fluorescent tube.

  However, since the light emitting diode is a point light source and has a strong directivity (straightness) of the light emitted from the light source, for example, the light emitting diodes are arranged in a grid pattern at predetermined intervals, and light emission is performed. When a light transmissive light diffusing sheet is disposed in front of the diode to form an illuminating body, the light transmissive light diffusing sheet portion corresponding to the light emitting diode is bright and the light transmissive light diffusing sheet portion not corresponding to the light emitting diode is present. Luminance unevenness that is dark occurs.

  In order to prevent the luminance unevenness, there is a method of increasing the distance between the light emitting diode and the light transmissive light diffusing sheet. However, there is a problem that it is difficult to reduce the thickness of the illumination body.

  As another method for preventing luminance unevenness, it is conceivable to increase the number of light emitting diodes to be used and to shorten the distance between the light emitting diodes. However, this increases the cost and increases the power consumption as an illuminating body. Has a problem.

  Therefore, in Patent Document 1, a light emitting diode with high light directivity is processed, or a lens member is attached to the light emitting diode to form a module, and light emitted directly above the central axis is converted into a module. A light emitting diode device in which the luminance distribution is adjusted to weaken the directivity of light has been proposed.

Further, in Patent Document 2, a point light source, a light reflecting member disposed around the point light source, a translucent light diffusion surface plate disposed so as to face the light reflecting member, and A light box having an opening formed on the light emitting side and having at least a case in which the point light source and the light reflecting member are housed; and a housing recess is formed by the light reflecting member; The point light source is disposed in the recess, and the luminance when the incident angle of light emitted from the point light source is 0 ° and a distance of 350 mm is 15000 cd / m ² or less, There is disclosed a light box that is used for illumination after a part or all of light emitted from a point light source is reflected by an inner surface of a peripheral wall portion of the housing recess.

  However, when the light box is applied to an existing product, the arrangement interval of the point light sources and the distance between the point light sources and the light diffusion surface plate are determined in advance, so that the shape of the storage recess is also limited. Therefore, there is a problem that it is difficult to design a light box having the configuration as described above.

JP 2006-286906 A JP 2008-270144 A

  The present invention provides an illuminating body that hardly causes luminance unevenness, can be reduced in thickness, and can be easily applied to existing products.

The illuminating body of the present invention has a plurality of recesses formed by thermoforming a light-reflecting thermoplastic resin sheet from the upper surface toward the lower surface, and the inner bottom surface of the recesses is provided with a light source. And a light reflecting member formed on a light reflecting surface for reflecting the light emitted from the light source, and an upper portion of the light reflecting member. A light-transmitting light diffusing sheet disposed on the light reflecting member, and the light source disposed on the light source disposing portion of the concave portion of the light reflecting member, wherein the concave portions are reflective surfaces having a flat front surface. While being connected by the connecting portion formed in the above, cut between the adjacent concave portions through a light source disposed in these concave portions and a plane orthogonal to the light transmissive light diffusion sheet At the cut surface, the light emission angle of the light source is θ, and The angle between the straight line passing through the light source and perpendicular to the light transmissive light diffusing sheet and the straight line passing through the light source and the opening end of the recess is α, and the connection connecting the recesses A straight line passing through the center of the width direction of the section and perpendicular to the light transmissive light diffusing sheet intersects the light transmissive light diffusing sheet and the light source, and passes through the light source and the light transmissive. When the angle formed by the straight line orthogonal to the light diffusion sheet is β, the following expression 1 is satisfied.
β ≦ α <θ Equation 1

Further, in the illuminating body, between the concave portions adjacent to each other, on a cut surface cut by a plane that passes through the light source disposed in the concave portions and is orthogonal to the light transmissive light diffusion sheet, An angle γ formed by a tangent at an arbitrary point on the light reflecting surface and a surface parallel to the light transmissive light diffusing sheet satisfies the following formula 2.
γ ≦ 90−β Equation 2

  And the said illumination body WHEREIN: A recessed part is a reverse truncated cone shape, It is characterized by the above-mentioned. In the above illuminating body, the concave portion has a reverse truncated pyramid shape.

  Since the illuminating body of the present invention has the above-described configuration, the light source is adjusted by adjusting the shape of the connecting portion formed between the recesses and adjusting the light emission angle θ and the angles α and β. Even if the number of the light source is limited in advance or the position of the light source is fixed, the shape of the recess is limited, or the distance between the light source and the light-transmitting light diffusing sheet is limited, the luminance is reduced or the luminance is uneven. It is possible to reduce the thickness while responding flexibly without making it.

It is the vertical end view which showed the illuminating body of this invention. It is the perspective view which showed the illuminating body of this invention. It is the partial front view which showed the recessed part of the light reflection member. It is the end elevation which showed a part of illumination body. It is the end elevation which showed a part of illumination body. It is the graph which showed an example of the luminance distribution of a light source. It is the partial front view which showed another example of the recessed part of the light reflection member. It is the perspective view which showed the recessed part of FIG. It is the partial front view which showed another example of the recessed part of the light reflection member. It is the perspective view which showed the recessed part of FIG. It is the partial front view which showed another example of the recessed part of the light reflection member. It is the perspective view which showed the recessed part of FIG. It is the end elevation which showed another example of the recessed part of a light reflection member. It is the partial front view which showed another example of the recessed part of the light reflection member. It is the perspective view which showed the recessed part of FIG. It is the partial front view which showed another example of the recessed part of the light reflection member.

  An example of the illumination body of the present invention will be described with reference to the drawings. The illuminating body L of the present invention includes a light reflecting member A, a light transmissive light diffusing sheet B disposed in front of the light reflecting member A, and light sources C, C and C disposed on the light reflecting member A. .. and have

  The light reflecting member A is formed by thermoforming the light reflecting thermoplastic resin sheet 1. As shown in FIG. 1, the light reflecting member A is swelled by thermoforming the planar rectangular thermoplastic resin sheet 1 from the front surface toward the rear surface in a portion excluding the outer periphery of the four sides. A number of inverted truncated quadrangular pyramid-shaped recesses 2, 2,... Are vertically and horizontally oriented with the opening edges of the recesses 2, 2,... Parallel to the long or short sides of the thermoplastic resin sheet 1. It is formed at predetermined intervals via a connecting portion 24 described later.

  Specifically, as shown in FIG. 3, the concave portion 2 has a flat bottom surface 21 with a flat top surface and a state in which the concave portion 2 gradually expands from the four-side outer periphery of the bottom surface portion 21 toward the front side. The peripheral wall portion 22 extends. In this peripheral wall portion 22, four inverted isosceles trapezoidal peripheral wall pieces 22a, 22a,... Share the opposite inclined sides over the entire length between the adjacent peripheral wall piece portions 22a, 22a. As a result, it is integrally formed in the circumferential direction of the bottom surface portion 21 and formed in a funnel shape, and the inner surface of the continuous portion 22b between the peripheral wall piece portions 22a and 22a is a smooth concave arc surface that is not cut or cracked over the entire length. The inner peripheral surface of the peripheral wall portion 22 is formed entirely on a light reflecting surface 22c that reflects light emitted from the light source C described later. Furthermore, the inner surface of the continuous portion between the peripheral wall portion 22 and the bottom surface portion 21 is also formed into a smooth concave arc surface, preferably a concave arc surface, that is completely free of cuts and cracks.

  The inner bottom surface of the concave portion 2, that is, the inner surface of the bottom surface portion 21, is a flat light source arrangement portion 23 for arranging a light source C such as a light emitting diode. The through hole 21a is provided between the front and rear surfaces, and the light source C can be arranged on the light source arrangement portion 23 through the through hole 21a.

  Further, the recesses 2, 2 adjacent to each other are integrated on the whole through the connection portions 24 formed in a lattice shape at the opening edges thereof. The front surface of the connection portion 24 is formed on a reflection surface 24a that is flat on the entire surface, and no irregularities are formed, and no cuts or cracks are formed.

  Next, a method for manufacturing the light reflecting member A will be described. First, the light-reflective thermoplastic resin sheet used as the material of the light reflecting member A is not particularly limited as long as it can reflect light. In the thermoplastic resin sheet, inorganic materials such as titanium oxide and calcium carbonate are used. Light reflectivity can be imparted by incorporating a filler.

  If the total light reflectivity of the thermoplastic resin sheet having light reflectivity is low, the light reflectivity of the light reflecting member may be lowered, so 96% or more is preferable, and 98 to 100% is more preferable.

  Further, if the ratio of the diffuse reflectance in the total light reflectance of the thermoplastic resin sheet having light reflectivity is low, the reflectivity in all directions of the light reflecting member may be lowered, so 90% or more. Preferably, 95 to 100% is more preferable.

  In addition, the light ray total reflectance and diffuse reflectance of the thermoplastic resin sheet are light rays having a wavelength of 550 nm when total reflection light measurement is performed under an incident condition of 8 ° in accordance with measurement method B described in JIS K7105. The total reflectance and diffuse reflectance were measured in an environment of room temperature 20 ° C. and relative humidity 60%. When the barium sulfate plate was used as a standard reflector, the total light reflectance and diffuse reflectance were 100. The relative value was used.

  The thermoplastic resin is not particularly limited, and examples thereof include polyethylene resins, polyolefin resins such as polypropylene resins, polyester resins, acrylic resins such as polymethyl acrylate, polyvinyl chloride resins, and polychlorinated resins. Examples thereof include diene resins such as vinylidene resins, fluorine resins, polyether resins, polyamide resins, polyurethane resins, polybutadienes, polyolefin resins are preferable, and polypropylene resins are more preferable. In addition, a thermoplastic resin may be used independently or 2 or more types may be used together.

  Examples of the polyethylene resin include low density polyethylene, linear low density polyethylene, high density polyethylene, and medium density polyethylene.

  Examples of the polypropylene resin include homopolypropylene, ethylene-propylene copolymer, propylene-α-olefin copolymer, and the like, since the volatile component is not generated even when the light reflecting member is heated. preferable. Further, when the light reflecting member is formed by foaming, the polypropylene resin is preferably a high melt tension polypropylene resin disclosed in Japanese Patent No. 2521388 or Japanese Patent Application Laid-Open No. 2001-226510. .

  In addition, the ethylene-propylene copolymer and the propylene-α-olefin copolymer may be either a random copolymer or a block copolymer. The content of the α-olefin component in the propylene-α-olefin copolymer is preferably 0.5 to 30% by weight, and more preferably 1 to 10% by weight.

  Examples of the α-olefin include α-olefins having 4 to 10 carbon atoms, such as 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene and the like. Is mentioned.

  The titanium oxide includes a rutile type, anatase type and ilmenite type, but a rutile type is preferred. And if titanium oxide has strong photocatalytic action, it will degrade the thermoplastic resin and cause the light reflectivity of the light reflecting member to decrease, so it is preferable to perform surface treatment.

  Although it does not specifically limit as the surface treatment method of the said titanium oxide, The method etc. which coat | cover with hydrous oxides, such as aluminum, silicon, titanium, zirconium, tin, etc. are mentioned.

  And, if the content of titanium oxide in the thermoplastic resin composition is small, the light reflectivity of the light reflecting member is lowered, while at most, the light reflecting of the light reflecting member is commensurate with the blending amount of titanium oxide. In addition to the improvement in properties, the light reflecting member is also reduced in lightness, so that it is preferably 10 to 100 parts by weight, more preferably 20 to 80 parts by weight, more preferably 30 to 65 parts by weight based on 100 parts by weight of the thermoplastic resin. Part by weight is particularly preferred.

  The thermoplastic resin sheet having light reflectivity may be a foamed sheet or a non-foamed sheet. First, as a method for producing a thermoplastic resin foam sheet having light reflectivity, a general-purpose method is adopted. For example, a thermoplastic resin, an inorganic filler and a foaming agent, and, if necessary, an additive to an extruder. A method of producing a thermoplastic resin foam sheet by supplying and melt-kneading to obtain a foamable thermoplastic resin composition, and extruding and foaming the foamable thermoplastic resin composition from a die attached to the tip of an extruder. . The die is not particularly limited as long as it is widely used in extrusion foaming, and examples thereof include a T die and an annular die.

  In the above production method, when a T die is used as the die, a thermoplastic resin foam sheet can be produced by extrusion foaming into a sheet form from an extruder, while when an annular die is used as the die. The cylindrical body is extruded and foamed from a circular die to produce a cylindrical body, and the cylindrical body is gradually expanded in diameter and then supplied to a cooling mandrel to be cooled. A thermoplastic resin foam sheet can be produced by cutting the inner and outer peripheral surfaces, opening them, and developing them.

  The blowing agent is not particularly limited, and is an organic gas such as saturated aliphatic hydrocarbons such as propane, butane and pentane, and halogenated hydrocarbons such as tetrafluoroethane, chlorodifluoroethane and difluoroethane; carbon dioxide and nitrogen gas. Gaseous inorganic compounds such as water; liquid inorganic compounds such as water; mixtures of organic acids or salts thereof with bicarbonate, such as a mixture of sodium bicarbonate and citric acid, dinitrosopentamethylenetetramine, etc. Solid foaming agents and the like are mentioned, and it is preferable to use a mixture of an organic acid or a salt thereof and bicarbonate and an organic gas, and a mixture of sodium bicarbonate and citric acid and an organic gas are used. It is more preferable to use together.

  Next, as a method for producing a non-foamed thermoplastic resin sheet having light reflectivity, a general-purpose method is employed. For example, the above-described thermoplastic resin, inorganic filler, and, if necessary, an extruder are used as an extruder. And a melt-kneaded composition to obtain a thermoplastic resin composition, and a method of producing a thermoplastic resin non-foamed sheet by extruding the thermoplastic resin composition into a sheet form from a T die attached to the tip of an extruder. .

  Furthermore, a thermoplastic resin foam sheet or a thermoplastic resin non-foamed sheet may be laminated and integrated on one surface of the thermoplastic resin sheet to form a laminated sheet. As a method for producing such a laminated sheet, a general-purpose method is employed. For example, (1) a thermoplastic resin foam sheet constituting a light reflecting member and a thermoplastic resin non-foamed sheet are laminated together by a coextrusion method. A method of integrating, (2) a method of laminating and integrating the thermoplastic resin non-foamed sheet constituting the light reflecting member and the thermoplastic resin foamed sheet by a co-extrusion method, and (3) heat constituting the light reflecting member. Examples include a method of extruding a thermoplastic resin non-foamed sheet on one surface of a thermoplastic resin foam sheet, and (4) a method of thermally laminating a thermoplastic resin non-foamed sheet on one surface of a thermoplastic resin foam sheet constituting a light reflecting member. Therefore, the method (1) (2) is preferable because the thickness of the non-foamed sheet can be easily adjusted. Among the above (1) and (2), the feed block method can be used. It is more preferable.

  Then, the above-mentioned thermoplastic resin foam sheet or thermoplastic resin non-foam sheet having light reflectivity is swelled in the vertical and horizontal directions by a large number of inverted truncated quadrangular pyramid-shaped recesses 2, 2. The light reflecting member A can be manufactured by forming the through hole 21a for disposing the light source in the bottom surface portion 21 of the recess 2 across the front and rear surfaces.

  Further, the light transmissive light diffusing sheet B is not particularly limited as long as it has light transmissive properties and light diffusing properties. For example, the light transmissive light diffusing sheet B includes a synthetic resin sheet containing a light diffusing agent and a light diffusing agent. Synthetic resin sheet with a coating film formed on the surface, synthetic resin sheet with concavo-convex processing on the surface, frosted glass (matte glass), flexible face sheet (Flexible Face Sheet), equipped with light diffusibility and light transmission Examples include woven fabrics. In addition, the light transmissive light-diffusion sheet B may be used independently or 2 or more types may be used together.

  Examples of the synthetic resin constituting the synthetic resin sheet include polymethyl methacrylate and polycarbonate. Examples of the light diffusing agent include silicone resin particles and particles made of a synthetic resin that is incompatible with the synthetic resin constituting the synthetic resin sheet.

  And as shown in FIG. 1, the illumination body L is comprised by arrange | positioning the light reflection member A, the light transmissive light diffusion sheet B mentioned later, and the light emitting diode C as a light source in the housing | casing 3. As shown in FIG. Has been.

  The casing 3 has a flat rectangular bottom surface portion 31 that is slightly larger than the light reflecting member A and a rectangular frame-shaped peripheral wall portion extending upward from the four-side outer periphery of the bottom surface portion 31. It consists of 32. The upper end of the inner peripheral surface of the peripheral wall portion 32 is formed with a step portion 32a over the entire periphery, and the light transmissive light diffusion sheet B is detachably disposed on the step portion 32a. ing. The light source of the illuminator C may be a general-purpose light source in addition to the light emitting diode, but is preferably a light emitting diode.

  The light reflecting member A is disposed on the inner bottom surface of the bottom surface portion 31 of the housing 3 such that the opening of the recess 2 is on the opening side of the housing 3. In the light reflecting member A, the upper surface of the bottom surface portion 21 of each recess 2 and the reflecting surface 24a of the connecting portion 24 and the upper surface of the bottom surface portion 31 of the housing 3 are arranged in parallel to each other.

  Further, the light emitting diode C is projected forward through the through hole 21a of the bottom surface portion 21 of the recess 2 in the light reflecting member A, and the light emitting diode C is disposed on the light source disposing portion 23 of the light reflecting member A. Yes. In addition, the luminescent color of the light emitting diode C is not specifically limited, For example, white, blue, green, yellow, red etc. are mentioned, You may use combining the light emitting diode C which has a different luminescent color.

  Further, a light transmissive light diffusing sheet B is detachably disposed on the step portion 32a of the peripheral wall portion 32 of the casing 3, and the light transmissive light diffusing sheet B includes the light reflecting member A and the light reflecting member A. The light-emitting diode C disposed on the member A is not in contact with the light-emitting diode C and is disposed at a predetermined distance forward from the opening end of the recess 2 of the light reflecting member A. The light transmissive light diffusion sheet B is disposed so as to be parallel to the bottom surface portion 21 of the concave portion 2 of the light reflecting member A. Further, the light transmissive light diffusing sheet B is disposed so as to be parallel to the reflecting surface 24a of the connecting portion 24 of the light reflecting member A.

The illuminating body L configured as described above passes through the light source C disposed on the light source disposition portion 23 of the recesses 2 and 2 between the recesses 2 and 2 adjacent to each other and transmits the light transmissive light diffusion sheet B. It has the structure which satisfy | fills the following conditions in the arbitrary cut surfaces cut | disconnected by the surface orthogonal to. When two arbitrary recesses 2 and 2 are defined, the other light-emitting diodes C on the light source disposition portion 23 of both recesses 2 and 2 are placed on the straight line connecting the points C ₁ and C ₁ on the other side. When the recess 2 is not interposed, the two recesses 2 and 2 are adjacent to each other.

Specifically, as shown in FIG. 4, a straight line P ₁ passing through the light emitting diode C and orthogonal to the light transmissive light diffusing sheet B is drawn. A straight line P ₂ passing through the light emitting diode C and the opening end 2a of the recess ₂ is drawn. The angle formed by the straight lines P ₁ and P ₂ is α (°). In the present invention, “passing through the light emitting diode C” means “passing through a point C ₁ on the surface of the light emitting diode C on the cut surface and in the center in the left-right direction of the light emitting diode C”. .

This angle α can be calculated in the following manner. On the straight line P _1, to draw a straight line P ₅ which is perpendicular to the straight line P ₁ from the open end 2a of the recess 2, when the intersection of the straight line P ₅ and the straight line P ₁ to a point X, the light emitting diode on the The distance between the point C ₁ and the point X is h ₁ . Further, the distance between the points C ₁ and C ₁ on the light emitting diodes C and C of the adjacent recesses 2 and 2 is d _0, and the width dimension of the connecting portion 24 is d ₁ . Then, the angle α (°) can be calculated based on the following equation.
α (°) = tan ⁻¹ [(d ₀ −d ₁ ) / 2h ₁ ]

Further, as shown in FIG. 5, a straight line P passing through the center 24b in the width direction of the reflection surface 24a of the connecting portion 24 connecting the adjacent recesses 2 and 2 and orthogonal to the light transmissive light diffusing sheet B. Draw ₃ A point where the straight line P ₃ intersects the light transmissive light diffusing sheet B is defined as B _1, and a straight line P ₄ passing through the point B ₁ and the light emitting diode C is drawn. An angle formed by the straight line P ₄ and the straight line P ₁ is β (°).

This angle β can be calculated as follows. On the straight line P ₁ , when the distance from the point C ₁ on the light emitting diode C to the rear surface of the light transmissive light diffusing sheet B is h ₀ , the angle β (°) can be calculated based on the following formula. .
β (°) = tan ⁻¹ (d ₀ / 2h ₀ )

The angle θ is a light emission angle of the light source (light emitting diode) C, and is measured in the following manner. As shown in FIG. 6, a light emitting diode C to be measured is prepared. A luminance meter K is arranged at a position 50 cm away from the point C ₁ on the light emitting diode C on a straight line perpendicular to the light source arrangement portion 23 from the point C ₁ on the light emitting diode C. As the luminance meter, for example, a spot luminance meter marketed under the trade name “CS-1000” from Konica Minolta, Inc., a spot luminance marketed under the trade name “BM-7” from Topcon Technohouse, Inc. A spectral radiance meter commercially available from Topcon Techno House under the trade name “SR-3AR” can be used.

Next, after the light emitting diode C is turned on, the luminance meter K is moved on a circle with a radius of 50 cm centered on the point C ₁ on the light emitting diode C, and the luminance meter is scanned at intervals of 1 ° to emit light. The brightness of the light emitted from the diode C is measured. Note that the measurement conditions of luminance by the luminance meter K are a measurement angle of 1 °, an ND filter of 10%, and an average number of times of 3 times / point.

In FIG. 6, a point E ₁ at which light from the light emitting diode C is no longer measured on the right side of the point C ₁ on the light emitting diode C and a point from the light emitting diode C on the left side of the point C ₁ on the light emitting diode C. light is identified and E ₂ that are no longer measured, connecting a line F ₁ connecting the C ₁ and the point E ₁ point on the light emitting diode C, the C ₁ and the point E ₂ points on the light emitting diode C line An angle that is ½ of the angle formed by F ₂ is defined as θ.

In the illuminating body L of the present invention, the light emission angle θ and the angles α and β defined as described above satisfy the following formula 1.
β ≦ α <θ Equation 1

  However, when light is emitted from the light emitting diode C in the illuminating body L of the present invention, since the light emission angle θ is equal to or larger than the angle α, the light emitted from the light emitting diode C is recessed. The light can be dispersed by being surely incident on the second light reflecting surface 22c and reflected by the light reflecting surface 22c. By making the dispersed light incident on the light transmissive light diffusing sheet B, the luminance of the light transmissive light diffusing sheet B can be made uniform.

  In the illuminator L of the present invention, the angle α is equal to or greater than the angle β, so that the light source distribution of one of the recesses 2 is between the recesses 2 and 2 adjacent to each other. The light emitted from the light emitting diode C disposed in the installation portion 23 is the light transmissive light diffusion sheet B portion located in front of the connection portion 24 that connects the recesses 2 and 2 adjacent to each other. The light emitted from the light-emitting diode C disposed in the light source disposition portion 23 of the other recess 2 is illuminated by at least one half of the one recess 2 and half of the one recess 2 side. Among the light-transmitting light diffusing sheet B portion located in front of the connecting portion 24 connecting the two and two, at least the other half portion on the other concave portion 2 side and the other half portion on the other concave portion 2 side are illuminated. Therefore, light emitted from the light-emitting diodes C and C disposed in the recesses 2 and 2 adjacent to each other is reliably transmitted to the light-transmitting light diffusion sheet B located in front of the connection portion 24 of the light reflecting member A. It can be made incident.

  Of the light incident on the light transmissive light diffusing sheet B as described above, a part of the light is transmitted through the light transmissive light diffusing sheet B, while a part of the light is transmitted by the light transmissive light diffusing sheet B. Reflected on the reflecting member A side.

  The light reflected on the light reflecting member A side is reflected again on the light transmissive light diffusing sheet B side by the light reflecting surface 22c of the concave portion 2 of the light reflecting member A and the reflecting surface 24a of the connecting portion 24. In this light reflection, the front surface of the connecting portion 24 of the light reflecting member A is entirely formed on a flat reflecting surface 24a, and is not formed in a convex arc shape, so that it is incident on the reflecting surface 24a of the connecting portion 24. The reflected light can be reliably reflected on the light transmissive light diffusing sheet B side, particularly on the light transmissive light diffusing sheet B portion located in front of the connecting portion 24 and the vicinity thereof. In this manner, the light emitted from the light emitting diode C passes through the light transmissive light diffusion sheet B while repeating multiple reflections between the light reflecting member A and the light transmissive light diffusion sheet B.

  As described above, the light emitted from the light emitting diode C is incident on the light transmissive light diffusing sheet B while repeating multiple reflections between the light reflecting member A and the light transmissive light diffusing sheet B. The light diffusing sheet B is separated from the light emitting diode C between the portion in front of the recess 2 of the light reflecting member A and the portion that is not, that is, the portion in front of the connecting portion 24 of the light reflecting member A. There is almost no difference in the light irradiation intensity, and therefore, the occurrence of uneven brightness in the light-transmissive light diffusing sheet B is suppressed.

  The light reflecting member A of the illuminating body L of the present invention has a connecting portion 24 formed on a reflecting surface 24a having a flat front surface between the recesses 2 and 2, and the shape of the connecting portion 24 is its width or the like. By adjusting the distance, the arrangement interval of the light emitting diodes C can be changed without changing the shape of the recess 2.

  Therefore, the illuminating body L of the present invention flexibly supports the shape of the concave portion 2, the arrangement state of the light emitting diode C, the existing product in which the distance between the light emitting diode C and the light transmissive light diffusing sheet B is fixed in advance. can do.

  Further, the light reflecting member A of the illuminating body L of the present invention has a flat reflecting surface 24a formed on the front surface of the connecting portion 24 connecting the recesses 2 and 2, so that the light reflecting surface of the recess 2 is formed. Without changing the inclination angle of 22c, the depth of the recess 2 can be formed shallower than when the recesses 2 and 2 are connected by a connection portion having an inverted V-shaped cross section. The illuminating body L can be made thin.

  Moreover, as described above, the light transmitting light diffusing sheet B portion located in front of the connecting portion 24 and in the vicinity thereof is formed by making the front surface of the connecting portion 24 connecting the recesses 2 and 2 flat. In addition, light from the light emitting diode C can be sufficiently incident by multiple reflection. Therefore, the illuminating body L of the present invention can reduce the thickness while suppressing the occurrence of luminance unevenness of the light transmissive light diffusing sheet B.

Further, as shown in FIG. 5, between the adjacent recesses 2, 2, the light passes through the light source C disposed on the light source disposition portion 23 of the recesses 2, 2, and enters the light transmissive light diffusion sheet B. A tangent line P ₆ at an arbitrary point on the light reflecting surface 22c of the recess 2 is drawn by a cut surface cut by a plane orthogonal to the surface, and the tangent line P ₆ and a plane parallel to the light transmissive light diffusion sheet B are drawn. It is preferable that the angle γ (°) formed by satisfy the following formula 2. Incidentally, when selecting an arbitrary point in the light reflecting surface 22c, when the light reflecting surface 22c part this point there is a flat surface having a certain inclination angle, replaced a tangent P ₆ and the light reflecting surface 22c portion Shall.
γ ≦ 90−β Equation 2

  If the relationship of γ ≦ 90−β is not satisfied, the light emitted from the light emitting diode C and reflected by the light reflecting surface 22c of the concave portion 2 is not easily reflected in the direction of the connecting portion 24 of the light reflecting member A. As a result, the light irradiation intensity at the portion of the light transmissive light diffusion sheet B corresponding to the front of the connecting portion 24 of the light reflecting member A corresponds to the front of the concave portion 2. This is because it becomes weaker than the light irradiation intensity in the light transmissive light diffusing sheet B, and uneven brightness occurs in the light transmissive light diffusing sheet B.

  The light reflecting surface 22c of the concave portion 2 is formed from a flat surface, and the angle γ does not change. However, like the concave portion 2 shown in FIGS. 14 and 15 described later, the light reflecting surface 22c of the concave portion 2 is formed. The inclination angle may be changed. In such a case, the angle γ takes a value closer to the lower limit side of the expression 2 as it becomes the front side of the recess 2, while the angle γ becomes closer to the rear side of the recess 2. It is preferable to configure the light reflecting surface 22c of the recess 2 so as to take a value close to the upper limit side of Expression 2.

  Although the case where the concave portion 2 is formed in a reverse truncated quadrangular pyramid shape has been described above, the concave portion 2 may have a reverse truncated pyramid shape other than the reverse truncated quadrangular pyramid shape. The truncated cone shape means a shape obtained by excising the top of the cone.

  Specifically, as shown in FIGS. 7 and 8, in the recess 2 of FIG. 1, the lower surface portion 21 is formed in a regular octagon shape, and the peripheral wall piece portions 22a and 22a are connected to each other in an isosceles triangular shape. A structure formed in a funnel shape by continuously connecting in the circumferential direction of the bottom surface portion 21 via 22b ′ may be used. This recess 2 also needs to satisfy the above formula 1. Since the structure of the light reflection member A other than the above has the same structure as the light reflection member A shown in FIG.

  Further, as shown in FIGS. 9 and 10, the concave portion 2 is extended in a plane regular hexagonal bottom surface portion 41 and a state where the concave portion 2 gradually expands forward from the four-side outer periphery of the bottom surface portion 41. The shape which consists of the surrounding wall part 42 may be sufficient.

  In the peripheral wall portion 42, six inverted isosceles trapezoidal peripheral wall pieces 42a, 42a,... Share the opposite inclined sides over the entire length between the adjacent peripheral wall piece portions 42a, 42a. As a result, a continuous funnel shape is formed continuously in the circumferential direction of the bottom surface portion 41, and the inner surface of the continuous portion 42b between the peripheral wall piece portions 42a, 42a is a smooth concave arc surface that is not cut or cracked over the entire length. The inner peripheral surface of the peripheral wall portion 42 is formed entirely on the light reflecting surface 42c that reflects the light emitted from the light source C. Furthermore, the inner surface of the connecting portion between the peripheral wall portion 42 and the bottom surface portion 41 is also formed into a smooth concave arc surface, preferably a concave arc surface, that is completely free of cuts and cracks. This recess 2 also needs to satisfy the above formula 1. Since the structure of the light reflection member A other than the above has the same structure as the light reflection member A shown in FIG.

  Moreover, as shown in FIG.11 and FIG.12, the recessed part 2 may be formed in the reverse truncated cone shape other than the inverted truncated pyramid shape. That is, the concave portion is formed by a planar circular bottom surface portion 61 and an inverted frustoconical peripheral wall portion 62 extending in a state of gradually expanding from the outer peripheral edge of the bottom surface portion 61 toward the front. It may be. This recess 2 also needs to satisfy the above formula 1. The structure of the light reflecting member A other than the above has the same structure as the light reflecting member A shown in FIG.

  In the above, the inclination angle of the light reflecting surface of each peripheral wall piece part constituting the peripheral wall part forming the concave part 2, that is, the angle γ reaches from the bottom part of the concave part 2 to the opening end of the concave part 2 Although the case where it has the same angle without changing has been described, the inclination angle of the light reflecting surface of each peripheral wall piece part constituting the peripheral wall part forming the concave part 2 is the bottom part of the concave part 2 It may change between 21 and the opening end 2a of the recess 2.

  Specifically, as shown in FIGS. 13 to 15, the recess 2 is extended in a state of gradually expanding toward the front from the outer peripheral edge of the bottom surface portion 51 having a square square shape and the bottom surface portion 51. It consists of a peripheral wall 52.

  The peripheral wall portion 52 is composed of four peripheral wall pieces 52a, 52a,... Between the adjacent peripheral wall pieces 52a, 52a by sharing the inclined sides facing each other over the entire length. It is continuously provided integrally in the circumferential direction and formed in a funnel shape.

Each peripheral piece portion 52a, the longitudinal direction of the two positions of the bent portion 52b, which is bent in the standing direction in 52c, the angle gamma ₁ in peripheral piece portion 52a portion of the rearward of the bent portion 52b, a bent portion 52b When the angle γ ₂ in the peripheral wall piece portion 52a portion between the bent portions 52c and the angle γ ₃ in the peripheral wall piece portion 52a portion ahead of the bent portion 52c are compared, the angle γ ₁ , the angle γ ₂ , and the angle γ ₃ are in this order. It is getting bigger. The angles γ _{1 to} γ ₃ are angles defined by the angle γ. The bent portions 52b (52c) of each peripheral wall piece portion 52a are connected in the circumferential direction of the bottom surface portion 51 to form a planar square frame shape. This recess 2 also needs to satisfy the above formula 1. The structure of the light reflecting member A other than the above has the same structure as the light reflecting member A shown in FIG.

In the above description, in the recesses 2, 2... Arranged in a grid pattern, the case where the edges forming the open ends of the recesses 2 adjacent in the vertical and horizontal directions are formed in parallel to each other has been described. As shown in FIG. 2, the concave portion 2 is so formed that the arbitrary concave portion 2 and the opening end of the concave portion 2 adjacent to the concave portion 2 in the vertical and horizontal directions are rotated by 90 ° clockwise in the drawing. 2 ... may be formed. When the recesses 2, 2... Are arranged in this way, the angles α and β measured on the left and right with respect to the straight line P ₁ may not take the same value. It is necessary to satisfy the above formula 1. In addition, since the shape of the recessed part 2 is the same structure as the recessed part 2 shown in FIG.9 and FIG.10, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In the recess 2, the case where only one light source C is disposed in the light source disposing portion 23 has been described, but a plurality of light sources C, C... May be disposed in the light source disposing portion 23. In this case, for each light source C, the light emission angle θ and the angles α and β need to satisfy the above formula 1.

(Example 1, Comparative Example 3)
A light reflecting sheet serving as a raw fabric of the light reflecting member A was prepared. In this light reflecting sheet, a thermoplastic resin non-foamed sheet was laminated and integrated on one surface of the thermoplastic resin foamed sheet. The light reflecting sheet had a thickness of 0.8 mm and an overall density of 0.8 g / cm ³ . The light reflecting sheet has a total light reflectance of 98.5%, a diffuse reflectance of 96.3%, and a ratio of the diffuse reflectance to the total light reflectance of 97.8% on the surface of the thermoplastic resin non-foamed sheet. Met.

  A planar light-reflective sheet having a side of 64 cm was cut out from the light-reflecting sheet. After heating the light reflecting raw sheet so that the surface temperature becomes 140 ° C., a part of the light reflecting raw sheet is moved from the thermoplastic resin non-foamed sheet side to the thermoplastic resin foamed sheet side by match molding. The recessed portions 2, 2... In a reverse truncated quadrangular pyramid shape are formed at predetermined intervals in the vertical and horizontal directions on substantially the entire surface of the light reflection raw sheet. A planar square through hole 21a is provided between the front and rear surfaces of the bottom surface portion 21 of each recess 2, and the light emitting diode C is formed on the light source arrangement portion 23 formed by the inner bottom surface of the bottom surface portion 21 through the through hole 21a. Was formed to be disposable. The bottom surface portion 21 of the recess 2 was formed in a planar square shape having a side of 6 mm. The open end of the recess 2 was formed in a planar rectangular shape having a long side of 27 mm and a short side of 24 mm.

  Then, a light-reflecting member A having a flat rectangular shape (A3 size) having a long side of 42 cm and a short side of 29.7 cm was obtained from the light-reflecting raw sheet in which the concave portion 2 was bulged (see FIG. 2). In the light reflecting member A, the long side direction of the entire shape and the long side direction of the recess 2 are made to coincide with each other.

  The inner surface of the continuous wall 22b between the peripheral wall pieces 22a and 22a of the recess 2 is formed into a smooth concave arc surface with no cuts or cracks over the entire length, and the inner peripheral surface of the peripheral wall 22 is entirely formed. The light reflecting surface 22c that reflects the light emitted from the light emitting diode C is formed. The inner surface of the connecting portion between the peripheral wall portion 22 and the bottom surface portion 21 was also formed as a smooth concave arc surface without any cuts or cracks. Further, the recesses 2 and 2 are connected to each other by a connecting portion 24 formed on a reflective surface 24a having a flat front surface. The connecting portion between the opening end of the recess 2 and the connection portion 24 was entirely formed on a smooth convex arc surface having no cuts or cracks.

  Next, a flat rectangular bottom surface portion 31 having a long side of 45.5 cm and a short side of 33.2 cm, and a rectangular frame-shaped peripheral wall portion having a height of 5 cm extending upward from the four-side outer periphery of the bottom surface portion 31. A housing 3 consisting of 32 was prepared. A stepped portion 32a was formed on the inner peripheral surface upper end portion of the peripheral wall portion 32 of the housing 3 over the entire periphery.

  An A3 size light emitting diode module in which light emitting diodes C, C... Are arranged in a grid pattern on the substrate on the inner bottom surface of the housing 3, and the light emitting diodes C, C. The light reflecting member A was laid on the light emitting diode module. The light emitting diode C of the light emitting diode module is disposed on the light source disposing portion 23 of each concave portion 2 of the light reflecting member A. The operating power of the light emitting diode module was 5.8W. The light emission angle θ of the light emitting diode C was 71 °.

  A light transmissive light diffusing sheet B (trade name “Acrylite” manufactured by Mitsubishi Rayon Co., Ltd., thickness 2 mm, total light transmittance: 58%) is detachably disposed on the step 32a of the housing 3. The illuminating body L was produced. The bottom surface portion 21 of the concave portion 2 of the light reflecting member A and the reflection surface 24a of the connection portion 24, the front and back surfaces of the light transmissive light diffusion sheet B, and the bottom surface portion 31 of the housing 3 are parallel to each other. It was arranged.

Between the recesses 2 and 2 adjacent to each other of the obtained illuminating body L, the light passes through the light-emitting diodes C disposed on the light source disposition portion 23 of the recesses 2 and 2 and is directed to the light transmissive light diffusion sheet B. An orthogonal surface, a surface parallel to the long side of the opening edge of the recess 2 (first surface), a surface parallel to the short side of the opening edge of the recess 2 (second surface), and the opening end of the recess 2 From the point C ₁ on the light emitting diode C to the rear surface of the light transmissive light diffusing sheet B, the angle being α, the angle β, the angle γ, and the cut surface cut by a plane parallel to the diagonal direction (third surface) at the edge distance h _0, emitting the point C ₁ and the distance h ₁ between the point X on the diodes, light emitting diodes C, C _1, the distance d ₀ between C ₁ point on C between adjacent concave portions 2,2, the connecting portion The width dimension d _{1 of} 24 was as shown in Tables 1-3.

(Example 2)
An illuminator L was produced in the same manner as in Example 1 except that the light reflecting raw sheet was formed by match molding so that the shape of the concave portion was a reverse truncated cone shape. In the obtained light reflecting member A, the bottom surface portion 21 of the recess 2 was formed in a planar circular shape having a diameter of 8.6 mm. The open end of the recess 2 was formed in a planar circular shape with a diameter of 26 mm.

Between the recesses 2 and 2 adjacent to each other of the obtained illuminating body L, the light passes through the light-emitting diodes C disposed on the light source disposition portion 23 of the recesses 2 and 2 and is directed to the light transmissive light diffusion sheet B. Orthogonal surfaces, a surface parallel to the long side of the entire light reflecting member A (first surface), a surface parallel to the short side of the entire light reflecting member A (second surface), the first surface and the second surface Is a light-transmitting light diffused from a point C ₁ on the light-emitting diode C at an angle α, an angle β, an angle γ, at a cut surface cut by a surface (third surface) that forms an angle of 45 ° with respect to each of distance h ₀ to the rear surface of the sheet B, the distance between the light emitting said points C ₁ and the distance h ₁ between the point X on the diodes, light emitting diodes C, C ₁ point on C between adjacent concave portions 2, 2, C ₁ d ₀ and the width dimension d ₁ of the connecting portion 24 were as shown in Tables 1 to 3.

(Example 3)
An illuminator L was produced in the same manner as in Example 1 except that the light reflecting raw sheet was formed by match molding so that the shape of the concave portion was a reverse truncated cone shape. In the obtained light reflecting member A, the bottom surface portion 21 of the recess 2 was formed in a planar circular shape having a diameter of 16.6 mm. The open end of the recess 2 was formed in a planar circular shape with a diameter of 26 mm.

Between the recesses 2 and 2 adjacent to each other of the obtained illuminating body L, the light passes through the light-emitting diodes C disposed on the light source disposition portion 23 of the recesses 2 and 2 and is directed to the light transmissive light diffusion sheet B. Orthogonal surfaces, a surface parallel to the long side of the entire light reflecting member A (first surface), a surface parallel to the short side of the entire light reflecting member A (second surface), the first surface and the second surface Is a light-transmitting light diffused from a point C ₁ on the light-emitting diode C at an angle α, an angle β, an angle γ, at a cut surface cut by a surface (third surface) that forms an angle of 45 ° with respect to each of distance h ₀ to the rear surface of the sheet B, the distance between the light emitting said points C ₁ and the distance h ₁ between the point X on the diodes, light emitting diodes C, C ₁ point on C between adjacent concave portions 2, 2, C ₁ d ₀ and the width dimension d ₁ of the connecting portion 24 were as shown in Tables 1 to 3.

(Comparative Example 1)
An illuminator L was produced in the same manner as in Example 1 except that the concave portions 2 and 2 were continuously formed so that no connection portion was formed between the concave portions 2 and 2. The bottom surface portion 21 of the recess 2 was formed in a planar square shape having a side of 6 mm. The open end of the recess 2 was formed in a planar rectangular shape having a long side of 35 mm and a short side of 32 mm.

Between the recesses 2 and 2 adjacent to each other of the obtained illuminating body L, the light passes through the light-emitting diodes C disposed on the light source disposition portion 23 of the recesses 2 and 2 and is directed to the light transmissive light diffusion sheet B. An orthogonal surface, a surface parallel to the long side of the opening edge of the recess 2 (first surface), a surface parallel to the short side of the opening edge of the recess 2 (second surface), and the opening end of the recess 2 From the point C ₁ on the light emitting diode C to the rear surface of the light transmissive light diffusing sheet B, the angle being α, the angle β, the angle γ, and the cut surface cut by a plane parallel to the diagonal direction (third surface) at the edge distance h _0, the distance h ₁ between the point C ₁ and point X on the light-emitting diodes, light emitting diodes C, the distance d ₀ between the C _1, C ₁ point on C between adjacent concave portions 2 and 2 Table 1 As shown in ~ 3.

(Comparative Example 2)
An illuminator L was produced in the same manner as in Example 1 except that a flat rectangular plate (A3 size) having a long side of 42 cm and a short side of 29.7 cm was cut out from the light reflecting raw sheet and used as a light reflecting member. .

  The luminance of the obtained illuminating body was measured in the following manner, and the result is shown in Table 4.

(Luminance evaluation of lighting body)
A two-dimensional luminance meter M (trade name “CA-2000, manufactured by Konica Minolta Co., Ltd.) is located 50 cm away from the center of the light transmissive light diffusing sheet B of the illuminator L in a direction orthogonal to the light transmissive light diffusing sheet B. )).

  Thereafter, all the light emitting diodes C, C... Of the illuminating body L were turned on, and the luminance was measured using the two-dimensional luminance meter M. Note that the measurement conditions were a synchronous setting of 60 Hz: 1/30, an ND filter of 1.5%, a dark color allowable value of 5.0%, and an integration count of 64 times.

  Luminance (light source portion luminance) of the portion corresponding to the front of the light emitting diode disposed on the light source arrangement portion 23 of each concave portion 2 in the light reflecting member A (long side direction 8 locations × short side direction 12 locations = 96 locations) The maximum brightness and the minimum brightness are shown in Table 4.

  Similarly, the luminance (non-light source portion luminance) of the portion corresponding to the front of the reflection surface 24a of the connection portion 24 of the light reflecting member A (long side direction 7 locations × short side direction 11 locations = 77 locations) is measured. The luminance and minimum luminance are shown in Table 4.

  Further, the luminance of the entire range of the light reflecting member A was measured, and the arithmetic average value of the luminances was defined as the average luminance. In addition, since the connection part was not formed in the light reflection member A of the comparative example 1, the continuous connection part of the opening edges of the recessed parts 2 and 2 was considered as a connection part, and the non-light source luminance was measured. Since the light reflecting member A of Comparative Example 2 is not formed with a concave portion and a connecting portion, the light source unit luminance and the non-light source unit luminance were measured at the same measurement locations as in Example 1.

  In addition, Table 4 shows the luminance unevenness as a value obtained by multiplying the value obtained by dividing the difference between the maximum luminance when the light source portion luminance is measured and the minimum luminance when the non-light source portion luminance is measured by the average luminance. .

1 Thermoplastic resin sheet
2a Open end 2 Recess 3 Housing
21 Bottom
22 Perimeter wall
22a Perimeter wall piece
22b Connection section
22c Light reflecting surface
23 Light source placement
24 connections
24a Reflective surface
41 Bottom
42 Perimeter wall
42a Perimeter wall piece
42b Connecting section
42c Light reflecting surface
51 Bottom
52 Perimeter wall
52a Peripheral wall piece A Light reflecting member B Light transmissive light diffusing sheet C Light source, light emitting diode L Illuminant θ Light radiation angle

Claims (4)

A light source disposing portion for disposing a plurality of recesses by expanding a thermoplastic resin sheet having light reflectivity from the front surface to the rear surface by thermoforming, and the inner bottom surface of the recesses disposes a light source. And a light reflecting member formed on the light reflecting surface for reflecting the light emitted from the light source, and a light transmitting member disposed in front of the light reflecting member. The illuminating light diffusing sheet and the light source disposed in the light source disposition portion of the concave portion of the light reflecting member, wherein the concave portions are connected to each other by a connecting portion formed on a reflective surface having a flat front surface. On the other hand, the light source is connected between the adjacent recesses and cut along a plane that passes through the light source disposed in these recesses and is orthogonal to the light-transmissive light diffusing sheet. And the light source is And an angle formed by a straight line perpendicular to the light transmissive light diffusing sheet and a straight line passing through the light source and the opening end of the concave portion is α, and the width direction of the connecting portion connecting the concave portions A straight line passing through the center of the light source and passing through the light source through the point where the straight line perpendicular to the light transmissive light diffusing sheet intersects the light transmissive light diffusing sheet and the light transmissive light diffusing sheet through the light source. An illumination body characterized by satisfying the following formula 1 when β is an angle formed by an orthogonal straight line.
β ≦ α <θ Equation 1 Arbitrary points on the light reflecting surface of the concave portion between the concave portions adjacent to each other on a cut surface cut through a light source disposed in the concave portions and perpendicular to the light transmissive light diffusing sheet. The illuminating body according to claim 1, wherein an angle γ formed by a tangent to the surface parallel to the light transmissive light diffusing sheet satisfies the following formula 2.
γ ≦ 90−β Equation 2 3. The illuminating body according to claim 1, wherein the concave portion has a reverse truncated cone shape. The illuminating body according to claim 1 or 2, wherein the concave portion has a reverse truncated pyramid shape.

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