JP2010108642A - Light reflecting plate, and illuminator body using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light reflecting plate with high luminance and little generation of luminance unevenness, even if light-emitting diodes are used as light sources. <P>SOLUTION: The light reflecting plate A is provided with a plurality of conical reflecting convex parts 2 formed on a thermoplastic resin sheet 1 with light reflectivity in longitudinal and lateral directions, with a surface of the reflecting convex parts 2 to be light reflecting surfaces 21, and with light source arrangement parts 4 for arranging light sources each formed on the thermoplastic resin sheet 1 between the reflecting convex pars 2, 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light reflector having excellent light reflectivity and an illuminating body using the same.

  Conventionally, a thermoplastic resin sheet is processed into a three-dimensional shape to form a light reflecting plate, and a light source such as a light emitting diode is disposed on the light reflecting plate, which is used as a lighting device. As such a light reflecting plate, in Patent Document 1, a light reflecting plate processed into a three-dimensional shape by forming a cut in a predetermined portion of a plastic film or sheet that reflects light and bending the cut along the cut. Is disclosed.

  However, since the light reflecting plate is formed with a notch in the thermoplastic resin sheet and bent along the notch, a gap due to the notch is generated on the light reflecting surface of the light reflecting plate. The light incident on the surface is not reflected in the gaps on the light reflecting surface, the light reflectivity is lowered, and the light reflected from the light reflecting plate is not uniform. Further, a process for forming a cut in the thermoplastic resin sheet is required, and the production efficiency is inferior.

  Furthermore, the reflective plate is formed with a ridge portion having a predetermined length having an inverted V-shaped cross section or a semicircular shape by folding a thermoplastic resin sheet in a mountain. Accordingly, light can enter only above the ridges from the side of the ridges (in the direction orthogonal to the length direction), and as a result, the sheet disposed above the reflector plate. Incident light becomes insufficient in the sheet portion located above the ridges, dark spots corresponding to the ridges appear on the sheet, the sheet cannot be illuminated uniformly, and uneven brightness occurs. It had the problem that it occurred.

  Further, in Patent Document 2, a wiring board installed at the bottom of a box whose front is open, a plurality of light emitting diodes installed on the wiring board, and a space between the light emitting diodes are filled up. A light box comprising a light reflecting plate and a translucent light diffusing surface plate installed in the front opening of the box is disclosed.

  However, since the light emitted from the light emitting diode is highly linear, the light diffusion surface plate has a bright part that is strongly received by the light from the light emitting diode and a dark part that is weakly irradiated with light. There was a problem that the surface plate was not illuminated uniformly.

  Furthermore, since the light diffused from the light diffusing surface plate is diffused in the surface direction of the light diffusing surface plate, there is a problem that the luminance when the light diffusing surface plate is viewed from the front is low.

WO2005 / 066664 JP 2006-202725 A

  The present invention provides a light reflecting plate having high luminance and less occurrence of luminance unevenness even when a light emitting diode is used as a light source, and an illuminating body using the light reflecting plate.

  In the light reflection plate of the present invention, a plurality of cone-shaped reflection convex portions are formed in the vertical and horizontal directions on a thermoplastic resin sheet having light reflectivity, and the surface of the reflection convex portion is a light reflection surface. In addition, a light source disposition portion for disposing a light source on the thermoplastic resin sheet between the reflection convex portions is formed.

  And in the said light reflection board, the reflective convex part is formed by expanding the thermoplastic resin sheet, It is characterized by the above-mentioned.

  Further, the light reflecting plate is characterized in that a light source arrangement portion is formed between reflection convex portions adjacent to each other in a direction crossing the vertical and horizontal directions. Further, the light reflecting plate is characterized in that the reflection convex portion is formed in a conical shape or a regular quadrangular pyramid shape.

  Furthermore, the illuminating body of the present invention is characterized in that a light emitting diode is disposed on the above-described light reflecting plate.

  In the light reflection plate of the present invention, a plurality of cone-shaped reflection convex portions are formed in the vertical and horizontal directions on a thermoplastic resin sheet having light reflectivity, and the surface of the reflection convex portion is a light reflection surface. In addition, a light source disposition portion for disposing a light source is formed on the thermoplastic resin sheet between the reflection convex portions, and the reflection convex portions are independent of each other and the light of the reflection convex portion. The reflecting surface is formed as an inclined surface inclined with an obtuse inclination angle with respect to the thermoplastic resin sheet.

  Therefore, the light emitted from the light source arranged in the light source arrangement part is reflected by the inclined light reflection surface of the reflection convex part, and light can be irradiated also vertically above the reflection convex part. The plate can reflect light almost uniformly over the entire surface.

  Moreover, when the reflective convex part is formed by expanding the thermoplastic resin sheet, it can be easily manufactured by thermoforming, and the light reflecting plate can be reduced in weight.

  In the light reflection plate, when the light source arrangement portion is formed between the reflection convex portions adjacent to each other in the direction intersecting the vertical and horizontal directions, the light source is arranged substantially uniformly around the reflection convex portion. And the light can be reflected more uniformly on the entire surface by the light reflecting plate.

  An example of the light reflecting plate of the present invention will be described with reference to the drawings. The light reflecting plate A is formed by thermoforming a thermoplastic resin sheet 1 having light reflectivity. As shown in FIGS. 1 and 2, the light reflection plate A is formed by thermoforming the flat rectangular thermoplastic resin sheet 1 from the one surface 10 toward the other surface 11 in a portion excluding the outer periphery of the four sides. By bulging by this, the shape of the top of the cone cut by a plane parallel to the other surface 11 of the thermoplastic resin sheet 1, that is, a large number of reflective convex portions 2, 2. It is formed in a grid pattern in a state of projecting independently without contacting each other with a predetermined interval in the vertical and horizontal directions. In addition, as the truncated cone shape shown in FIG. 1, the top of the cone whose apex is located on a line passing through the center of the true circular bottom surface and perpendicular to the bottom surface is parallel to the other surface 11 of the thermoplastic resin sheet 1. Although the shape cut off by a flat surface is shown, the top of the cone that passes through the center of the true circular bottom and is not positioned on a line perpendicular to the bottom is parallel to the other surface 11 of the thermoplastic resin sheet 1 The top of the cone whose top is located on a line that passes through the intersection of the major axis and minor axis of the elliptical bottom surface and is perpendicular to the bottom surface is parallel to the other surface 11 of the thermoplastic resin sheet 1. Parallel to the other surface 11 of the thermoplastic resin sheet 1 is the shape cut by the surface, or the top of the cone passing through the intersection of the major axis and minor axis of the elliptical bottom surface and the vertex not located on the line perpendicular to the bottom surface It may be a shape cut off on a smooth surface.

  The surface of the reflective convex portion 2 is a smooth light reflecting surface 21, and the light reflecting surface 21 of the reflective convex portion 2 is inclined with an obtuse angle α with respect to the other surface 11 of the thermoplastic resin sheet 1. It reflects the light emitted from the light source L, which will be described later, and the reflected light reflected on the other surface 11 of the reflective convex portion 2 and the thermoplastic resin sheet 1. In addition, the other surface 11 of the thermoplastic resin sheet 1 in which the reflective convex part 2 is not formed also has light reflectivity, the light radiated | emitted from the light source L, the reflective convex part 2, and the thermoplastic resin sheet 1 The reflected light reflected by the other surface 11 is reflected.

  Further, as shown in FIG. 3, the centers 2b, 2b,... Of the perfect circles 2a, 2a,. A planar rectangular light source arrangement portion 4 that penetrates the thermoplastic resin sheet 1 across both surfaces is formed at the intersection of the diagonal lines 31 and 31 of each virtual quadrangle 3, and a light emitting diode is provided in the light source arrangement portion 4. Such a light source L can be arranged.

  The thermoplastic resin sheet having light reflectivity used as the material of the light reflecting plate 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. The thermoplastic resin sheet may be foamed or non-foamed.

  If the total light reflectivity of the light-reflective thermoplastic resin sheet is low, the light reflectivity of the light reflection plate is lowered. Therefore, 96% or more is preferable, and 97 to 100% is more preferable.

  The total light reflectance of the thermoplastic resin sheet is the light reflectance at a wavelength of 550 nm when the total reflected light measurement is performed under an incident condition of 8 ° in accordance with the measurement method B described in JIS K7105. The measurement was carried out in an environment of 20 ° C. and a relative humidity of 60%, and the value was shown as a relative value when the light reflectance when a barium sulfate plate was used as a standard reflecting plate was taken as 100.

  The thermoplastic resin is not particularly limited, and examples thereof include polyethylene resins such as low density polyethylene, linear low density polyethylene, high density polyethylene, and medium density polyethylene, homopolypropylene, ethylene-propylene copolymer, and propylene. -Polyolefin resins such as polypropylene resins such as α-olefin copolymers, polyester resins, acrylic resins such as methyl polyacrylate, polyvinyl chloride resins, polyvinylidene chloride resins, fluorine resins, polyethers Examples include diene resins such as olefin resin, polyamide resin, polyurethane resin, and polybutadiene, polyolefin resin is preferable, and polypropylene resin is more preferable. In addition, a thermoplastic resin may be used independently or 2 or more types may be used together.

  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 deteriorate the thermoplastic resin and cause the light reflectivity of the light reflecting plate to decrease, so it is preferable to perform surface treatment.

  The thermoplastic resin sheet 1 includes an antioxidant, a copper damage inhibitor (metal deactivator), an antistatic agent, a dispersant such as a metal stearate soap, a quencher, a lactone processing stabilizer, a fluorescent whitening agent. An agent, a crystal nucleating agent, or the like may be added.

  The light reflection plate A is formed of a light-reflective thermoplastic resin sheet having a large number of reflection convex portions 2, 2... At a predetermined interval in the vertical and horizontal directions from one surface 10 to the other surface 11 by a general-purpose thermoforming method. Can be produced by forming a light source disposing portion 4 penetrating over both surfaces of the thermoplastic resin sheet 1 at a predetermined position between the reflective convex portions 2, 2. As thermoforming methods, for example, vacuum forming such as straight method, drape method, snapback method, reverse draw method, air slip method, plug assist method, pug assist / pre-blow method, air slip / plug assist method, press method, etc. And match mold molding.

  Next, the illumination device B using the light reflecting plate A will be described. First, as shown in FIG. 4, the illuminating device B is configured by arranging a light reflector A and an illuminating body C including a light emitting diode as a light source L in a housing 5. The casing 5 includes a flat rectangular bottom surface 51 having a size slightly larger than the light reflecting plate A, and a rectangular frame-shaped peripheral wall portion extending upward from the four-side outer periphery of the bottom surface 51. And 52. A step 52a is formed on the upper end of the inner peripheral surface of the peripheral wall 52 over the entire circumference, and the frosted glass or the optical sheet 6 is detachably disposed on the step 52a. Yes. The light source of the illuminator C may be a general-purpose light source in addition to the light emitting diode.

  Further, a light source body 7 is prepared in which a large number of light emitting diodes L, L... Are arranged on a planar rectangular substrate 71 having a size that can be laid on the bottom surface portion 51 of the housing 5. Note that, in a state where the light reflection plate A is superimposed on the light source body 7, the positions of the light source arrangement portions 4 and the light emitting diodes L of the light source body 7 coincide with each other.

  The light source body 7 is laid on the bottom surface portion 51 of the housing 5 with the light emitting diode L facing upward (in the opening direction of the housing 5). Is arranged, and the light emitting diode L of the light source body 7 is disposed on the light source disposition portion 4 of the light reflection plate A in a state of projecting to the other surface side of the thermoplastic resin sheet 1 to constitute the illuminating body C.

  In using this lighting device B, first, a frosted glass or an optical sheet 6 is detachably disposed on the step portion 52a of the peripheral wall portion 52 of the housing 5, and then the light emitting diode L is caused to emit light (FIG. 4). reference). Then, the light emitted radially from the light emitting diode L and incident on the light reflecting surface 21 of the reflecting projection 2 of the light reflecting plate A is reflected once or a plurality of times by the light reflecting surface 21 and travels in the traveling direction. Is directed toward the frosted glass or optical sheet 6 and is incident on the frosted glass or optical sheet 6. In addition, it is preferable that the light reflection plate A of the illuminating body C and the frosted glass or the optical sheet 6 are not adhered to each other.

  At this time, the frosted glass or the optical sheet 6 portion located above the top surface 21a of the reflective convex portion 2 is less likely to reach the light emitted from the light emitting diode L directly compared to the other portions. Therefore, in the light reflection plate A of the present invention, the reflection convex portions 2, 2... Are formed in an independent state, and the light emitting diodes L, L. ing.

  Accordingly, light is emitted from all directions of 360 ° in the horizontal direction from the light emitting diode L surrounding the reflective convex portion 2 to the reflective convex portion 2. And since the light reflection surface 21 of the reflective convex part 2 is formed in the inclined surface inclined with the obtuse angle (alpha) with respect to the other surface 11 of the thermoplastic resin sheet 1, the light radiated | emitted from the light emitting diode L is Reflected by the light reflecting surface 21 of the reflecting convex portion 2, a part of the light is reflected and directed toward the upper side of the top surface 21 a of the reflecting convex portion 2, and is positioned above the top surface 21 a of the reflecting convex portion 2. The frosted glass or the optical sheet 6 is smoothly incident on the frosted glass or the optical sheet 6, and the frosted glass or the optical sheet 6 shines substantially uniformly when viewed from the front.

  In addition, since the light reflecting surface 21 of the light reflecting plate A is not cut or cracked, the light incident on the light reflecting surface 21 is diffused and reflected by the light reflecting surface 21 so that the traveling direction is fogged glass or optical. It is directed almost certainly in the direction of the sheet 6.

  The optical sheet 6 contains therein a light diffusing agent such as organic particles or inorganic particles that diffuse light, and the light incident on the optical sheet 6 is irregularly reflected by the light diffusing agent in the optical sheet 6. Alternatively, the light incident on the frosted glass is diffused by the frosted glass and further diffused and then emitted outward from the frosted glass or the optical sheet 6. When seen, it is in a state of shining almost uniformly on the entire surface.

  Thus, since the frosted glass or the optical sheet 6 is illuminated by the light emitted from the light emitting diode L with a substantially uniform light beam over the entire surface, the position of the light emitting diode is visually recognized through the frosted glass or the optical sheet 6. There is almost nothing.

  And the design and the character drawn directly on the frosted glass or the optical sheet 6, or the design or the character drawn on the decorative sheet disposed on the frosted glass or the optical sheet 6, is the frosted glass or the optical sheet 6. The light radiated uniformly from the entire surface clearly and uniformly emerges and can be suitably used as an advertising device or a display device.

  In the light reflection plate A, the case where the reflection convex portion 2 is formed in a truncated cone shape has been described. However, without reflecting the top of the reflection convex portion 2, the reflection convex portion 2 has a conical shape as shown in FIG. You may form in a shape. 5 has the same structure as that of the light reflecting plate A shown in FIG. 1 except that the shape of the reflective convex portion is different. In the light reflecting plate A of FIG. 5, the conical shape is shown as a conical shape whose apex is located on a line that passes through the center of the true circular bottom surface and is perpendicular to the bottom surface. A cone shape whose vertex is not located on a line passing through and perpendicular to the bottom surface, or a cone shape whose vertex is located on a line passing through the intersection of the long axis and short axis on the bottom surface of the ellipse and perpendicular to the bottom surface, or an ellipse A conical shape that does not have a vertex on a line that passes through the intersection of the long axis and the short axis on the bottom surface of the shape and is perpendicular to the bottom surface may be used.

  In the light reflecting plate A, the case where the wall portion is not formed on the outer peripheral edge of the thermoplastic resin sheet 1 of the light reflecting plate A has been described. However, as shown in FIG. A rectangular frame-shaped peripheral wall portion 1a is projected upward from the outer periphery of the four sides, and this peripheral wall portion 1a bulges inward to form only a portion 2c of the reflection convex portion 2; Also good. In addition, the part 2c of the reflective convex part formed in the surrounding wall part 1a is formed in the same way as the other reflective convex part 2, if the whole is formed temporarily. The light reflecting plate A of FIG. 6 has the same shape as the light reflecting plate A shown in FIG. 1 except that a rectangular frame-shaped peripheral wall portion 1a is formed and a part 2c of the reflective convex portion 2 is formed on the peripheral wall portion 1a. Since the same structure is adopted, the same reference numerals are given and the description is omitted.

  In this way, the peripheral wall portion 1a is formed on the outer peripheral edge of the light reflection plate A, and a part 2c of the reflective convex portion 2 is formed on the peripheral wall portion 1a. The reflected light can be reflected by the light reflecting surface 21 of the reflection convex portion 2 almost without leakage, and light can be incident in the direction of the frosted glass or the optical sheet 6, and the frosted glass or the optical sheet 6 can be illuminated with higher brightness. Can do.

  Further, in the light reflecting plate A, the case where the reflective convex portions 2 are formed in a truncated cone shape or a conical shape has been described. However, as shown in FIG. That is, the shape obtained by cutting the top of the regular quadrangular pyramid with a surface parallel to the other surface 11 of the thermoplastic resin sheet 1 may be used. 7 has the same structure as that of the light reflecting plate A shown in FIG. 1 except that the shape of the reflective convex portion is different, and therefore the same reference numerals are given and description thereof is omitted. In the light reflector A in FIG. 7, the top of the regular quadrangular pyramid whose apex is located on a straight line that passes through the intersection of the diagonal lines of the square bottom surface and is perpendicular to the bottom surface is formed into a thermoplastic regular quadrangular pyramid shape. Although the shape cut by a plane parallel to the other surface 11 of the resin sheet 1 is shown, the top of the quadrangular pyramid whose apex is not located on a straight line passing through the intersection of the diagonal lines of the square bottom surface and perpendicular to the bottom surface is shown. Heat the top of a quadrangular pyramid whose apex is located on a straight line that passes through the intersection of the diagonal lines of the rectangular bottom surface and is perpendicular to the bottom surface. The shape of the plastic resin sheet 1 cut in a plane parallel to the other surface 11 and the top of a quadrangular pyramid whose apex is not located on a straight line passing through the intersection of the diagonal lines of the rectangular bottom surface and perpendicular to the bottom surface is thermoplastic It is a shape that is cut out in a plane parallel to the other surface 11 of the resin sheet 1 It may be.

  On the outer peripheral surface of the reflective convex portion 2, four flat light reflecting surfaces 21b, 21b,... That reflect light are continuously formed via the ridge line 21c, and as shown in FIG. The reflection surface 21b is formed in a state of facing the light source arrangement portion 4. In this way, by forming the reflection convex portion 2 in a state where the light reflection surface 21b faces the light source arrangement portion 4, light emitted from the light source L arranged in the light source arrangement portion 4 is effectively obtained. It can be reflected and is preferable. It should be noted that the ridge line 21c of the reflective convex portion 2 faces the light source arrangement portion 4, that is, in the reflective convex portion 2 of FIG. 7, 45 clockwise or counterclockwise on the other surface 11 of the thermoplastic resin sheet 1. The reflection convex portion 2 may be formed in a rotated state, but the light reflectivity is slightly inferior because the light reflecting surface 21 of the reflective convex portion 2 does not face the light source arrangement portion 4. There is.

  Further, in the light reflecting plate A of FIG. 7, the reflective convex portions 2, 2... Are formed in an independent state without being in contact with each other, but as shown in FIG. .. May be formed in a state where the reflection convex portions 2 and 2 adjacent to each other in the vertical and horizontal directions are in contact with the corner portions 2d and 2d of the bottom surfaces thereof. The light reflecting plate A in FIG. 8 has the same structure as the light reflecting plate A shown in FIG.

  Further, in the light reflecting plate A shown in FIGS. 7 and 8, the case where the reflective convex portion 2 is formed in a truncated quadrangular pyramid shape has been described. However, as shown in FIG. You may form in a pyramid shape. 9 has the same structure as that of the light reflecting plate A shown in FIG. 1 except that the shape of the reflection convex portion is different, and thus the same reference numerals are given and description thereof is omitted. In the light reflection plate A in FIG. 9, the regular quadrangular pyramid shape has a regular quadrangular pyramid shape whose apex is located on a straight line that passes through the intersection of the diagonal lines of the square bottom surface and is perpendicular to the bottom surface. A quadrangular pyramid shape whose vertex does not lie on a straight line that passes through the diagonal line of the bottom surface of the square and on a straight line that passes through the intersection point of the diagonal line of the rectangular bottom surface and that is perpendicular to the bottom surface It may be a quadrangular pyramid shape or a quadrangular pyramid shape whose apex is not located on a straight line that passes through the intersection of diagonal lines of a rectangular bottom surface and is perpendicular to the bottom surface.

  In the light reflecting plate A, the case where the reflection convex portion 2 is formed by bulging a part of the thermoplastic resin sheet 1 by thermoforming has been described. However, by injection molding or the like, it is formed on any surface of the thermoplastic resin sheet. The light reflecting plate A may be configured by integrally projecting the reflective convex portions 2, 2,.

  Further, in the light reflecting plate A, the case where the reflective convex portion 2 is formed in a conical shape, a quadrangular pyramid shape, a truncated conical shape, and a truncated quadrangular pyramid shape has been described. However, the reflective convex portion 2 has a triangular pyramid shape, Even if it is formed in a polygonal pyramid shape such as a pentagonal pyramid shape or a hexagonal pyramid shape, or a truncated polygonal pyramid shape formed by cutting the top of this polygonal pyramid with a surface parallel to the other surface 11 of the thermoplastic resin sheet Good.

Example 1
A tandem type extruder in which the second stage single-screw extruder (caliber: 115 mm) is connected to the tip of the first-stage single-screw extruder (caliber: 90 mm) via a connecting tube, and a single shaft having a diameter of 90 mm An extruder was prepared, and the second stage single-screw extruder of the tandem type extruder and the single-screw extruder having a diameter of 90 mm were both connected to the joining die, and an annular die was connected to the joining die.

Homopolypropylene (trade name “PF814” manufactured by Sun Allomer Co., Ltd., melt flow rate: 2.8 g / 10 min, density: 0.9 g / cm ³ ) 50 parts by weight, homopolypropylene (trade name “PL500A” manufactured by Sun Allomer Co., Ltd.), melt flow Late: 3.3 g / 10 min, density: 0.9 g / cm ³ ) 30 parts by weight, masterbatch containing rutile titanium oxide in an ethylene-propylene block copolymer (trade name “manufactured by Toyo Ink Co., Ltd.” PPM 1KB662 WHT FD ", ethylene-propylene block copolymer: 30% by weight, titanium oxide: 70% by weight) 20 parts by weight, thermoplastic comprising 1.0 part by weight of a mixture of sodium bicarbonate and citric acid as a foaming agent The resin composition is supplied to the first stage extruder and melt-kneaded at 200 ° C. And the foamed thermoplastic resin composition and further kneaded by press-fitting 1.16 parts by weight of butane (isobutane / n-butane (weight%) = 35:65) to the first stage of the extruder with respect to part.

  Subsequently, the foamable thermoplastic resin composition is continuously supplied from the first-stage single-screw extruder to the second-stage single-screw extruder through the connecting pipe to cool the foamable thermoplastic resin composition to 170 ° C. After that, it was continuously fed to a confluence die attached to the tip of the second stage single screw extruder.

On the other hand, homopolypropylene (trade name “PL500A” manufactured by Sun Allomer Co., Ltd., melt flow rate: 3.3 g / 10 min, density: 0.9 g / cm ³ ) 50 parts by weight, rutile type in the ethylene-propylene block copolymer. 50 parts by weight of a master batch containing titanium oxide (trade name “PPM 1KB662 WHT FD” manufactured by Toyo Ink Co., Ltd., ethylene-propylene block copolymer: 30% by weight, titanium oxide: 70% by weight), as a primary antioxidant 0.1 parts by weight of a phenolic antioxidant (trade name “IRGANOX1010” manufactured by CIBA), 0.1 part by weight of a phosphorus antioxidant (trade name “IRGAFOS168” manufactured by CIBA) as a secondary antioxidant, UV absorption Benzotriazole UV absorber (trade name “TINUVIN 326 manufactured by CIBA Co., Ltd.) ) 0.15 parts by weight and hindered amine light stabilizer (trade name “TINUVIN111” manufactured by CIBA) 0.15 parts by weight of non-foaming thermoplastic resin composition is supplied to a single screw extruder having a diameter of 90 mm Then, after melt-kneading at 200 ° C., it was kept at 190 ° C. at the tip of the extruder and continuously fed to a confluence die attached to the tip of the extruder.

  Then, a foamable thermoplastic resin composition extruded from the second single-screw extruder of the tandem extruder, and a non-foamable thermoplastic resin composition extruded from a single-screw extruder having a diameter of 90 mm A non-foaming heat layer laminated on the outer surface of a foamable thermoplastic resin composition layer having an annular cross section made of a foamable thermoplastic resin composition and joined by a joining die. A foamable laminate comprising a non-foamable thermoplastic resin composition layer comprising a plastic resin composition is formed, and the foamable laminate is supplied to an annular die connected to a merging die, and from the annular die to a cylindrical shape A cylindrical foam was obtained by extrusion foaming. The annular die had an inner diameter of 140 mm and a slit interval of 0.6 mm at the opening.

Thereafter, the cylindrical foam is taken up while gradually expanding the diameter, and molded along a cylindrical cooling mandrel having a diameter of 424 mm and a length of 500 mm, in which cooling water of 25 ° C. is circulated. However, after cooling by blowing air over the entire outer peripheral surface of the cylindrical foam from the air outlet of the air ring arranged in a state surrounding the cooling mandrel, the cylindrical foam is opposed to the diametrical direction. The laminated sheet in which the thermoplastic resin foam sheet is laminated and integrated on one surface of the thermoplastic resin non-foamed sheet constituting the light reflecting plate is obtained by cutting between the inner and outer peripheral surfaces at a point and opening and developing. . The obtained laminated sheet has an overall thickness of 0.7 mm, a thermoplastic resin non-foamed sheet thickness of 0.3 mm, a thermoplastic resin foamed sheet thickness of 0.4 mm, and an overall density of 0.8 g / cm. It was ³ . The total light reflectance of the thermoplastic resin non-foamed sheet surface of the laminated sheet was 98.8%.

  A planar square-shaped raw material sheet having a side of 64 cm was cut out from the laminated sheet. Next, the raw material sheet is heated so that the surface thereof is 140 ° C., and the raw material sheet is swelled from the thermoplastic resin foam sheet side toward the thermoplastic resin non-foamed sheet side by match molding to form the raw material sheet. A large number of frusto-conical reflection convex portions 2, 2,... Are formed in a vertical and horizontal direction at predetermined intervals.

  Further, at the intersection of diagonal lines 31, 31 of each virtual square 3 formed by connecting the centers 2b of the perfect circles 2a forming the bottom surfaces of the reflective convex portions 2, 2. After forming the light source disposition part 4 having a planar square shape that penetrates the raw material sheet between both sides, the raw material sheet is cut from a predetermined position to obtain a flat rectangular shape (A3 size) having a length of 42 cm and a width of 29.7 cm. The light reflector A was obtained. FIG. 10 is a plan view showing half of the light reflecting plate A in the vertical direction.

  In addition, the reflective convex part 2 had a diameter of 22.4 mm at the bottom and a height of 9.2 mm. The diameter of the top surface 21a of the reflective convex part 2 was 4 mm. The distance between the centers of the bottom surfaces of the reflective convex portions 2 and 2 was 32 mm in the vertical direction and 35 mm in the horizontal direction. The surface of the reflection convex portion 2 of the obtained light reflection plate A was the light reflection surface 21 as a whole. Twelve light source arrangement portions 4 were formed in the vertical direction and eight in the horizontal direction.

(Example 2)
The raw material sheet is swelled from the thermoplastic resin foam sheet side to the thermoplastic resin non-foamed sheet side by match molding, and the truncated convex quadrangular pyramid-shaped reflective projections 2, 2,. A light reflecting plate A was obtained in the same manner as in Example 1 except that a large number of .beta.

  In addition, the reflective convex part 2 had a square shape with a bottom of 19.2 mm on one side and a height of 9.2 mm. The top surface 21a of the reflective convex part 2 was a square shape with a side of 3.4 mm. The distance between the intersections of the diagonal lines of the bottom surfaces of the reflective convex portions 2 and 2 was 32 mm in the vertical direction and 35 mm in the horizontal direction. The light reflecting surface 21 b formed continuously via the ridge line 21 c in the reflective convex portion 2 was opposed to the light source arrangement portion 4. The surface of the reflection convex portion 2 of the obtained light reflection plate A was the light reflection surface 21 as a whole.

(Comparative Example 1)
A light reflecting plate A was obtained in the same manner as in Example 1 except that only the light source arrangement part 4 was formed without forming the reflective convex part in Example 1.

(Measurement of brightness)
A backlight unit directly under the light emitting diode (trade name “FN-DLA4” manufactured by Future Light) was prepared. In this backlight unit, eight light emitting diodes L, L,... Are arranged in a grid pattern on an A4 size substrate in the long side direction and in the short side direction. The operating power was 5.8W.

  This backlight unit was made into an A3 size backlight by connecting its long sides. Then, the light emitting diodes L of the backlight unit were arranged on the light source arrangement portions 4,... Of the light reflection plate A in a state of projecting to the thermoplastic resin non-foamed sheet side to produce an illuminating body.

  A transparent double-sided mud diffusion plate D (made by Kuraray Co., Ltd., acrylic resin extrusion plate, Transmittance: 78%) and A3 size, 2 mm thick milk half diffuser E (Made by Mitsubishi Rayon Co., Ltd., acrylic resin extruded plate, light transmittance: 58%) in parallel with the substrate of the backlight unit. In addition, the diffusion plate E is disposed on the light reflection plate A side. Furthermore, a two-dimensional luminance meter (trade name “CA-2000” manufactured by Konica Minolta Co., Ltd.) was disposed at a position 50 cm away from the intersection of the diagonal lines in plan view on the diffusion plate D in the normal direction.

  Then, all the light emitting diodes L were turned on, and the average luminance was measured using a two-dimensional luminance meter. 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.

  The luminance of the portion corresponding to the upper side of the top surface 21a of the reflective convex portion 2 (7 horizontal locations × 11 vertical locations = 77 locations) was measured, and the average value of the luminances was defined as the non-light source luminance. The luminance of the portion corresponding to the upper side of the light emitting diode L (8 horizontal locations × 12 vertical locations = 96 locations) was measured, and the average value of the luminances was defined as the light source luminance. Portions corresponding to the upper side of the top surface 21a of the reflective convex portion 2 (7 horizontal positions × 11 vertical positions = 77 locations), corresponding portions above the light emitting diode L (8 horizontal positions × 12 vertical positions = 96 locations), and The luminance of the portion corresponding to the upper part of the intermediate portion between the light emitting diodes L adjacent in the vertical and horizontal directions was measured, and the average value of the luminances was defined as the average luminance. In addition, since the reflective convex part is not formed in the light reflection board A of the comparative example 1, when measuring the brightness | luminance of the part corresponding to the upper direction 21a of the reflective convex part 2, it reflects like Example 1. The brightness | luminance of the part corresponding to the upper direction of the top face of the reflective convex part at the time of assuming that the convex part was formed was measured. In Table 1, the luminance uniformity refers to the luminance obtained by dividing the non-light source luminance by the light source luminance.

It is the perspective view which showed the light reflecting plate of this invention. It is sectional drawing which showed the light reflection plate of this invention. It is the model top view which showed the bottom face part of the reflective convex part in the light reflection board of this invention. It is sectional drawing which showed the illuminating device using the light reflection plate of this invention. It is the perspective view which showed another example of the light reflection board of this invention. It is the perspective view which showed another example of the light reflection board of this invention. It is the perspective view which showed another example of the light reflection board of this invention. It is the perspective view which showed another example of the light reflection board of this invention. It is the perspective view which showed another example of the light reflection board of this invention. 3 is a plan view showing a part of a light reflecting plate manufactured in Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermoplastic resin sheet 2 Reflection convex part 4 Light source arrangement | positioning part
21 Light reflecting surface A Light reflecting plate B Illuminating device C Illuminating body L Light source

Claims (5)

On the thermoplastic resin sheet having light reflectivity, a plurality of cone-shaped reflection convex portions are formed in the vertical and horizontal directions, and the surface of the reflective convex portion is a light reflecting surface, and between the reflective convex portions. A light reflection plate, wherein a light source disposition portion for disposing a light source is formed on the thermoplastic resin sheet. The light reflecting plate according to claim 1, wherein a reflection convex portion is formed by expanding the thermoplastic resin sheet. The light reflecting plate according to claim 1, wherein a light source arrangement portion is formed between reflection convex portions adjacent to each other in a direction intersecting the vertical and horizontal directions. The light reflecting plate according to claim 1, wherein the reflection convex portion is formed in a conical shape or a regular quadrangular pyramid shape. An illuminating body, wherein a light-emitting diode is disposed on the light reflecting plate according to any one of claims 1 to 4.

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