JP2011187254A - Light guide plate and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide plate keeping practical mechanical characteristics proper, having excelling designability, and capable of imparting three-dimensional degrees of freedom, and to provide a lighting system. <P>SOLUTION: A substrate made of a thermal plastic resin and provided with a dot-pattern or grooves aligned and formed on at least one of the surfaces is heat-bend processed into a three-dimensional shape; the substrate has two or more of continuous bent surfaces; and it is desirable that the cross-section of one end side of the substrate have a waveform which is substantially a sine wave. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light guide plate and a lighting device.

  A light guide plate made of a thermoplastic resin is installed in a signboard, a display, or the like, and is used for the purpose of changing light from a so-called edge light type light source into uniform surface light emission. In recent years, the use of light guide plates not only for signboards and displays but also for lighting applications has been expanded.

  As a light guide plate used for such illumination applications, a flat plate whose surface is subjected to uneven processing or pattern printing is known. Moreover, as an illuminating device using this, the light guide plate is disposed inside a box-type illuminating device, light is incident from an edge light type light source from a cross section of the light guide plate, and the main surface of the illuminating device is A device that emits light from a plate surface is known.

  As a light guide plate used in this type of lighting device, the following Patent Document 1 describes a thermoplastic resin light guide plate in which conical hole patterns having gradually different sizes or V groove patterns having gradually different depths are formed. Has been.

  Further, as this type of lighting device, Document 2 below describes a device in which a light guide plate and a diffusion sheet are stacked in this order on both sides of a reflection sheet. In this apparatus, a linear light source is mounted so as to straddle the end surfaces of two light guide plates, and the light irradiated in the in-plane direction of the light guide plate is reflected on both the front and back surfaces in the perpendicular direction by the reflection sheet.

JP 2005-276453 A JP-A-10-187075

  However, the light guide plate described in the above-mentioned document is of a type that is disposed or fitted in the lighting device, and its basic structure is a planar shape, and its design is limited. For this reason, in such an illumination device using the conventional light guide plate, there are restrictions on designability and three-dimensional freedom, and there is a restriction on illumination design that requires design freedom. In addition, if a flat light guide plate is bent inside a lighting device or is fitted in a stressed state, there is a risk of cracking due to long-term use, and there is concern about mechanical properties in practical use. was there.

  The present invention has been made in view of the above problems, and provides a light guide plate and a lighting device that are excellent in design and capable of imparting a three-dimensional degree of freedom while maintaining good practical mechanical characteristics. It is.

Such a subject can be achieved by the present invention described in the following (1) to (9).
(1) A substrate made of a thermoplastic resin and formed by arranging printed or uneven dot patterns or grooves on at least one surface is heat-bent into a three-dimensional curved surface, and the substrate is A light guide plate having two or more continuous curved surfaces.
(2) The light guide plate according to (1), wherein a cross section on one end side of the base material has a substantially sinusoidal wave shape.
(3) A substrate made of a thermoplastic resin and formed by arranging printed or uneven dot patterns or grooves on at least one surface is heat-bent into a three-dimensional curved surface, and the substrate is A light guide plate having two or more curved surfaces and a plane connecting the curved surfaces.
(4) The light guide plate according to (3), wherein a cross section on one end side of the base material has a shape in which arcs and straight lines are alternately continued.
(5) The light guide plate according to (3), wherein a cross section on one end side of the base material has a shape in which substantially sine waves and straight lines are alternately continued.
(6) The light guide plate according to any one of (1) to (5), wherein the thermoplastic resin is an acrylic resin. (7) An inorganic or organic transparent filler is blended with the thermoplastic resin ( The light guide plate according to any one of 1) to (6) (8) The light guide plate according to any one of (1) to (7), wherein the thickness of the base material is 2 mm or more and 10 mm or less. (1) It has the light-guide plate described in any one of (8), and an edge light type light source, The illuminating device characterized by the above-mentioned.

  According to the present invention, there are provided a light guide plate and an illuminating device that are excellent in design and can be imparted with a three-dimensional degree of freedom while maintaining good practical mechanical characteristics by being subjected to hot bending.

(A) is a perspective view of the light-guide plate in which the cross section of the one end side of the base material which concerns on this invention has a waveform shape of a substantially sine wave, (b) is the sectional drawing. (A) is a perspective view of the light-guide plate in which the cross section of the one end side of the base material which concerns on this invention has the shape by which the circular arc and the straight line were continued continuously, (b) is the sectional drawing. (A) is the perspective view of the light-guide plate which the cross section of the one end side of the base material which concerns on this invention has the shape by which the substantially sine wave and the straight line were continued alternately, (b) is the sectional drawing. is there. (A) is a perspective view of the illuminating device which equips the periphery of the light-guide plate based on this invention with an edge light type light source, (b) is an enlarged view of the peripheral part.

  Hereinafter, embodiments of a light guide plate and a lighting device according to the present invention will be described.

  The light guide plate of the present invention is made of a thermoplastic resin, and a substrate formed by arranging printed or uneven dot patterns or grooves on at least one surface is formed into a three-dimensional curved surface. The material has two or more continuous curved surfaces.

  Here, the printed or uneven dot pattern or groove (hereinafter sometimes referred to as a light guide pattern) is a printed part or uneven part for changing light from a so-called edge light type light source to uniform surface emission. It is. The light guide pattern may be formed only on one main surface of the base material, or may be formed on both main surfaces.

  The light guide pattern is formed on the base material by pressing a sheet material made of a thermoplastic resin, preferably a thermoplastic resin, against a press mold plate surface made of metal or the like on which the light guide pattern is engraved. Is made by Or it is made by printing a pattern on the sheet material surface made of a thermoplastic resin.

As a form of the light guide pattern, a dot pattern, particularly a halftone dot pattern in which cylindrical or hemispherical convex portions are two-dimensionally distributed and arranged on the surface of the substrate is preferable. Alternatively, a halftone dot pattern in which circular dot pattern-shaped printing parts are dispersedly arranged on the surface of the substrate is preferable.
In the case of a groove pattern in which grooves such as V-grooves are formed in a stripe shape or a lattice shape, there is a possibility that the groove angle varies due to the heat bending process of the substrate and the light guide characteristics vary. On the other hand, in the case of a dot pattern in which printed portions or convex portions are dispersedly arranged, even if the entire base material is curved by thermal bending, the convex portions are based on the protruding direction with respect to the base material and the shape of the convex portions themselves are maintained. Since the printing part moves following the material, and the printing unit moves following the base material as it is, fluctuations in the light guide characteristics are reduced.

  The hot press temperature can be set with reference to about + 60 ° C. or higher than the deflection temperature under load and glass transition temperature of the thermoplastic resin used. Thereby, the formation position and shape of the light guide pattern can be realized with high accuracy as desired. The deflection temperature under load is also referred to as a heat distortion temperature, and can be measured according to ASTM D648 or JIS 7191.

  The thermoplastic resin used in the present invention is not particularly limited, but preferably has transparency, acrylic resin (methacrylic resin), polycarbonate resin, polyvinyl chloride resin, amorphous polyester resin, amorphous olefin type. Resins, polystyrene resins, AS resins (acrylonitrile, styrene copolymer compounds) can be exemplified. Among these, by using acrylic resin in particular, it is possible to obtain a light guide plate having a high average luminance and a low luminance distribution.

The acrylic resin preferably contains 50% by mass or more of methyl methacrylate from the viewpoint of transparency.
In addition, the acrylic thermoplastic resin used in the present invention may contain an alkyl (meth) acrylate monomer other than methyl methacrylate or an aromatic vinyl compound as a copolymerization component. Furthermore, the thermoplastic resin may contain additives such as impact strength improvers and flame retardants.

  As long as the optical performance of the light guide plate is not impaired, it is preferable to add an inorganic or organic transparent filler to the thermoplastic resin. By adding such a filler, it is possible to improve the light diffusion effect and suppress the occurrence of uneven brightness. Examples of such inorganic or organic transparent fillers include glass beads and silica powder as inorganic fillers, and transparent resin beads and powders such as methacrylic resin as organic fillers.

  The thermoplastic resin may be provided with a reinforcing agent or flame retardancy as long as the optical performance of the light guide plate is not impaired.

  As described above, the substrate of the present invention is formed by printing or dot patterns or grooves arranged in advance on at least one surface.

  The thickness of the substrate is preferably 2 mm or more and 10 mm or less. More preferably, it is 3 mm or more and 8 mm or less. By using a substrate having a thickness in the above range, it is possible to efficiently guide the light of an edge light type light source (hereinafter sometimes referred to as light source light) to the light guide plate, and to retain the shape after the heat bending process. When it is used in a lighting device, practical mechanical strength can be obtained. In addition, by using a base material having a thickness in the above range, it is possible to balance shortening of heating time, improvement of productivity, and weight reduction.

  The light guide plate of the present invention is characterized in that a base material is heat-bent into a three-dimensional curved surface, and the base material has two or more continuous curved surfaces.

  In other words, by being heat-bent into such a curved surface, it becomes a light guide plate that is excellent in design and can be given three-dimensional freedom, and an illumination device using this light guide plate is excellent in design. It will be rich in three-dimensional freedom. In addition, by performing the thermal bending process, it is easy to ensure practical mechanical characteristics with less distortion compared to the case where stress is applied to a planar substrate.

  Here, a three-dimensional curved surface is a figure that is defined by two independent parameters in a three-dimensional space and cannot be established by plane deformation.

  As described above, in the present invention, the three-dimensional curved surface is characterized in that the base material has two or more continuous curved surfaces. At this time, the cross section on one end side of the base material is substantially sinusoidal. It is preferable to have a corrugated shape. Moreover, the base material at this time can be substantially rectangular in a plan view.

  The shape of the sine wave is not strict in the present invention, and includes a so-called corrugated shape. Although there is no restriction | limiting in particular about the degree of a waveform, It is preferable that a curvature radius (R) is 200 mm or more and 700 mm or less in a curved surface part. By setting such a radius of curvature (R), it is possible to provide a design that can give a three-dimensional degree of freedom while maintaining good practical mechanical properties with less distortion after hot bending. .

  In the present invention, the substrate has two or more curved surfaces and a plane connecting them.

  At this time, it is preferable that the cross section of the one end side of a base material has the shape by which the circular arc and the straight line were continued continuously.

  Moreover, it is preferable that the cross section of the one end side of a base material has the shape by which the substantially sine wave and the straight line were continued continuously.

  In this way, the substrate has a shape having two or more curved surfaces and a plane connecting them, in particular, a cross section on one end side, a shape in which arcs and straight lines are alternately continued, or a cross section on one end side, By adopting a shape in which approximately sine waves and straight lines are alternately continued, the lighting device using this light guide plate has excellent design and a high degree of freedom in three dimensions, and adjacent light guide plates. By connecting the flat portions of each other, a more integrated lighting device can be provided. In addition, also in the circular arc and the substantially sine wave at this time, it is preferable that the radius of curvature (R) is 200 mm or more and 700 mm or less in the curved surface portion. By setting such a radius of curvature (R), it is possible to provide a design that can give a three-dimensional degree of freedom while maintaining good practical mechanical properties with less distortion after hot bending. .

  As the method of the thermal bending process of the present invention, a gold having a concave surface (female type) and a convex surface (male type) curved in a state heated to a heating deflection temperature +10 to 40 ° C. of a thermoplastic resin as a base material. This is done by pressing the substrate against the mold. More specifically, when the thermoplastic resin is mainly composed of an acrylic resin, the heating temperature can be set to 110 ° C. or higher and 150 ° C. or lower. Specifically, it is preferably performed at 130 ° C. or higher and 150 ° C. or lower.

The heating temperature of the base material at this time is set to be equal to or lower than the melting point of the thermoplastic resin.
By setting the temperature of the base material during heating to a deflection temperature under load of + 40 ° C. or lower and a melting point or lower, the shape of the light guide pattern provided on the surface of the base material is not destroyed, and the light source light before and after the thermal bending process It is possible to suppress the fluctuation of the reflection angle. Thereby, the brightness fall in a light-guide plate and the nonuniformity of brightness distribution can be prevented. Moreover, the distortion to a light-guide plate can be suppressed by setting it as such heating temperature conditions.

  Furthermore, the base material at the time of heating can be processed into a desired shape in accordance with the mold shape at the time of hot bending by setting the temperature of the base material to the deflection temperature under load + 10 ° C. or higher. In other words, the mold reproducibility of the substrate can be maintained. Thereby, since the internal distortion of the base material subjected to the heat bending process is suppressed, the mechanical properties of the molded light guide plate are improved, and specifically, deformation during long-term use and cracking during application of impact are prevented.

  In the present invention, the specific method of hot bending is not particularly limited. For example, the heated substrate is pressed by a mold having a curved concave surface (female) and a convex surface (male). A molding method is also employed. Or you may roll the base material set with respect to the concave surface with the roller.

  Hereinafter, embodiments according to the present invention will be described more specifically with reference to the drawings.

1A is a perspective view of a light guide plate 1 (1a) in which a cross section on one end side of a base material according to the present invention has a substantially sinusoidal wave shape, and FIG. 1B is a cross sectional view thereof. It is.
This light guide plate 1a is a mold having a concave surface (female type) and a convex surface (male type) that are curved in a substantially sinusoidal wave shape by using a thermoplastic resin as a base material and forming a cylindrical dot pattern. The substrate is sandwiched between and heated in a heat-circulating oven at a heating temperature of the thermoplastic resin to a heating temperature of 10 to 40 ° C. It has been made. The light guide plate 1a of the present invention can be suitably used as an illuminating device that is rich in design and capable of providing three-dimensional freedom by adopting such a substantially sinusoidal wave shape.

(A) of FIG. 2 is a perspective view of the light guide plate 1 (1b) in which the cross section on one end side of the substrate according to the present invention has a shape in which arcs and straight lines are alternately continued, (b) FIG.
The light guide plate 1b has a concave surface (female type) and a convex surface (male type) in which a circular column and a straight line are alternately formed using a thermoplastic resin as a base material and formed with a cylindrical dot pattern. A base material is sandwiched between molds and heated to a heating temperature of 10-40 ° C with a thermoplastic resin in a heat circulating oven. It was obtained by processing. The light guide plate 1b according to the present invention has such a design that the cross section at one end side is alternately formed with arcs and straight lines, so that the light guide plate 1b has excellent design characteristics. (Plane flat part) It can connect and can use suitably as an illuminating device which can provide a three-dimensional freedom degree.

(A) of FIG. 3 is a perspective view of the light guide plate 1 (1c) in which the cross section on one end side of the base material according to the present invention has a shape in which substantially sine waves and straight lines are alternately continued. b) is a sectional view thereof.
This light guide plate 1c is a concave surface (female type) in which a methacrylic resin having a thickness of 8 mm is used as a base material, and a light guide plate in which a cylindrical dot pattern is formed of acrylic resin is formed in a shape in which substantially sinusoidal waves and straight lines are alternately continued. Depending on the thickness and dimensions of the light guide plate 1c, the substrate is sandwiched between molds having a convex surface (male mold) and heated to a heating temperature of 10 to 40 ° C. in the heat circulation oven. It is obtained by pressing for a required time and hot bending. The light guide plate 1c of the present invention has such a design that the cross section at one end side is substantially continuous with a sinusoidal wave and a straight line, so that the light guide plate is connected with each other between the flat portions of the end portions. It can be connected and can be suitably used as a lighting device capable of providing a three-dimensional degree of freedom.

4A is a perspective view of an illuminating device 2 in which an edge light type LED light source 2a is mounted on the periphery of the light guide plate 1a according to the present invention, and FIG. 4B is an enlarged view thereof.
In this illuminating device 2, the light guide plate 1 has a substantially rectangular shape in plan view, and uses a light guide plate 1a having a corrugated shape with a substantially sinusoidal cross section on one end side.
A diffusion plate 2c is installed on the front surface of the light guide plate 1a, and the reflective film 2b is attached to the cross section of two sides of the light guide plate 1a which is the back surface and the light incident portion where light is not incident, and another adjacent light incident light. An edge light type LED light source 2a is mounted on each of the two sides. In the figure, an example in which the edge light type LED light source 2a is mounted on the cross section of two pieces is shown, but there is no particular limitation as long as the mounting position of the edge light type light source 2a is a cross section of one or more pieces of the light guide plate 1. , All cross sections of four sides may be used. Moreover, although the LED light source was shown in the figure in edge light type light source 2a kind, there is no restriction | limiting in particular in the kind of light source.
Such a lighting device 2 is different from a box-type lighting device in which a light guide plate is fitted and mounted in a conventional device, and a free design utilizing curved surfaces is obtained and practical mechanical characteristics are excellent. It will be kept.

  Next, examples of specific embodiments of the light guide plate and the lighting device of the present invention will be described.

Example 1
<Wave-shaped light guide plate 1>
A light guide plate (Lumiking manufactured by Sumitomo Bakelite Co., Ltd.) in which a methacrylic resin of length 2440 mm x width 240 mm x thickness 8 mm is used as a base material and a cylindrical dot pattern is formed with acrylic resin is placed in a thermal circulation oven at a temperature of 150 ° C for 20 minutes. The sample was heated and hot-bended by a male and female mold having a continuous curved surface with a radius of 196 mm and a pitch of 740 mm. A diffusing plate (Sumitex 032 2mm manufactured by Sumitomo Chemical Co., Ltd.) is installed on the surface of the corrugated light guide plate obtained in this way, and a reflective film (white film manufactured by Inaba Electric Co., Ltd.) is installed on the back surface and the cross section of the light incident part. did. Further, an illumination device was manufactured by installing an edge light type light source (LED: Three One manufactured by Inaba Electric Co., Ltd.) on a predetermined cross section.
Next, light was incident on the inside of the light guide plate from an edge light type light source in the illumination device. When the illuminance before and after thermal bending was measured at a point 500 mm away from the light guide plate using an illuminometer, the illuminance change was about 4% and there was almost no difference in illuminance before and after processing.

(Example 2)
<Wave-shaped light guide plate 2>
A light guide plate (Lumiking manufactured by Sumitomo Bakelite Co., Ltd.) in which a methacrylic resin of length 2440 mm x width 240 mm x thickness 5 mm is used as a base material and a cylindrical dot pattern is formed with acrylic resin is 12 minutes in a 150 ° C thermal circulation oven. It was heated and hot-bended by a male and female mold having a continuous curved surface with a radius of 281 mm and a pitch of 925 mm. A diffusion plate (Sumitex 032 2mm manufactured by Sumitomo Chemical Co., Ltd.) was installed on the surface of the corrugated light guide plate thus obtained, and a reflective film (white film manufactured by Inaba Electric Co., Ltd.) was installed on the back surface and the cross section of the light incident part. Then, an illuminating device was manufactured by installing an edge light type light source (LED: Three One manufactured by Inaba Electric Co., Ltd.) on a predetermined cross section.
Next, light was incident on the inside of the light guide plate from a dilight type light source in the illumination device. When the illuminance before and after thermal bending was measured at a point 500 mm away from the light guide plate using an illuminometer, the illuminance change was about 4% and there was almost no difference in illuminance before and after processing.

(Example 3)
<Wave-shaped light guide plate 3>
A light guide plate (Lumiking manufactured by Sumitomo Bakelite Co., Ltd.) in which a cylindrical dot pattern is formed of acrylic resin with a methacrylic resin of length 1000mm x width 300m x thickness 5mm as a base material in a thermal circulation oven at a temperature of 135 ° C It was heated for 25 minutes and molded by a mold in which a curved surface having a radius of 217.5 mm and a flat surface having a size of 196 mm were combined continuously.
Next, light was incident on the inside of the light guide plate from an edge light type light source in the illumination device. When the illuminance before and after thermal bending was measured at a point 500 mm away from the light guide plate using an illuminometer, the illuminance change was about 5 to 6%, and there was almost no difference in illuminance before and after processing.

  As described above, in Examples 1 to 3, the change in illuminance before and after the processing was within 6%, which was suppressed to a level with no practical problem.

  As can be seen from the above Examples 1 to 3, the light guide plate and the lighting device according to the present invention have practically no problem with a decrease in illuminance and unevenness after hot bending, and are excellent in design and three-dimensional. It was possible to give a degree of freedom.

DESCRIPTION OF SYMBOLS 1 Light-guide plate 1a Light-guide plate where the cross section of the one end side of a base material has a waveform shape of a substantially sine wave 1b The light-guide plate 1c which the cross section of the one end side of a base material has the shape by which the circular arc and the straight line were continued alternately The light guide plate in which the cross section on one end side of the base material has a shape in which substantially sine waves and straight lines are alternately continued 2 Illuminating device 2a Edge light type LED light source 2b Reflective film 2c Diffusion plate

Claims (9)

  A base material made of a thermoplastic resin and formed by arranging printed or uneven dot patterns or grooves on at least one surface is heat-bent into a three-dimensional curved surface, and there are two or more base materials. A light guide plate having a continuous curved surface.   The light guide plate according to claim 1, wherein a cross section on one end side of the base material has a substantially sinusoidal wave shape.   A base material made of a thermoplastic resin and formed by arranging printed or uneven dot patterns or grooves on at least one surface is heat-bent into a three-dimensional curved surface, and there are two or more base materials. A light guide plate having a curved surface and a plane connecting the curved surface.   The light guide plate according to claim 3, wherein a cross section on one end side of the base material has a shape in which arcs and straight lines are alternately continued.   The light guide plate according to claim 3, wherein a cross section on one end side of the base material has a shape in which substantially sine waves and straight lines are alternately continued.   The light guide plate according to claim 1, wherein the thermoplastic resin is an acrylic resin. The light guide plate according to any one of claims 1 to 6, wherein an inorganic or organic transparent filler is blended in the thermoplastic resin.   The light guide plate according to any one of claims 1 to 7, wherein the base material has a thickness of 2 mm or more and 10 mm or less.   An illumination device comprising the light guide plate according to claim 1 and an edge light type light source.

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