JP5144077B2 - A sheet-shaped light transmission body and an illumination device including the sheet-shaped light transmission body. - Google Patents

Description

  The present invention provides a flexible and flexible sheet-like optical transmission in which a core part made of a transparent organic polymer obtained by melt extrusion using a die having a slit-like discharge port is covered with a clad part. The present invention relates to an illuminating device including a sheet-like light transmission body and a light source device optically connected to at least one end of the sheet-like light transmission body.

  The plastic optical transmission body is easily used in end face processing and handling, and has advantages such as being inexpensive, lightweight, and having a large diameter, and thus is used in lighting applications, sensor applications, and communication applications. In particular, a plastic optical transmission body has a feature of preventing electricity and heat from passing through, and since only a light source device is required as an apparatus and it is easy to install, it has been frequently used in lighting applications in recent years.

  Recently, among light plastic optical transmission materials for lighting, it is illuminated in a line like detecting pinholes in sheets and paper, or the back of a personal computer display, keyboard, mobile phone screen, liquid crystal panel, and touch control panel. There is a growing demand for an illumination medium that can illuminate a wide area and that is flexible and flexible in order to illuminate in a planar manner like a light.

  Many proposals have been made regarding such a sheet-shaped light transmission body and illumination body, and a method for manufacturing the same.

  For example, Patent Document 1 proposes a light detection device using a light guide obtained by processing a sheet-like light guide material (for example, a transparent acrylic plate).

  In Patent Documents 2 and 4, a plurality of optical fiber cores formed by coating a plastic optical fiber (POF) having a core-cladding structure are arranged in parallel, and the plurality of optical fiber core wires are collectively bundled. A tape-type optical fiber core wire having a protective coating made of a reactive silicone-based cured resin has been proposed.

  Further, Patent Document 3 proposes a sheet-like POF formed by thermocompression bonding a plurality of POFs in a close-contact parallel state.

  Patent Document 5 proposes a planar light-emitting illumination device in which light from a light-emitting diode (LED) is input from the side surface of a transmissive material that transmits planar light.

Patent Documents 6 and 7 propose a sheet-type optical path in which a clad portion is formed by applying a coating solution in which transparent resin beads are dissolved in an organic solvent to an acrylic resin sheet or the like as a core portion (dip coating method). ing.
JP-A 63-236025 JP-A-6-201957 JP-A-6-317716 JP 2000-121898 A JP 2004-186124 A JP-A-2005-340160 Japanese Patent Laying-Open No. 2005-300672

  However, the light guide part of the light guide described in Patent Document 1 is composed only of the core part and has an air layer as a cladding. However, in this type of light guide, the side surface of the light guide is damaged. Then, light leaks from that portion, or actually transmitted light oozes out from the core portion, so the distance that light can be transmitted is very short, and it is difficult to develop it for lighting applications.

  In addition, in the sheet-like POFs described in Patent Documents 2, 3, and 4, there is a problem that a process for binding POF strands prepared in advance to a sheet shape is necessary and the number of processing steps increases. There is. Furthermore, since each POF strand is separated by a clad, in order to illuminate the entire sheet uniformly, it is necessary to make light incident uniformly on all the POF strands. There are problems that the number of processing steps is increased and that the POF strands are arranged to reduce the area of the core portion and reduce the amount of light received.

  Only glass is described as a member constituting the flat light emitter described in Patent Document 5, and does not have soft flexibility. In addition, there is a problem that the number of steps increases because mirror processing is required in a later process in order to form a reflecting surface that serves as a cladding.

  In the sheet type optical path manufactured by the dip coating method described in Patent Documents 6 and 7, it is difficult to uniformly control the thickness of the clad, and the organic solvent used for the clad coating liquid is a core. There is a problem that some materials may be dissolved. For this reason, when used as an illumination application, unevenness in the amount of light occurs, or the light transmission performance is insufficient, making it difficult to apply to the manufacture of a sheet-type optical path having a small sheet thickness. In addition, the dip coating method has a problem in that it requires coating, drying, and curing treatments and increases the number of processing steps.

  An object of the present invention is to provide a sheet-like optical transmission body that has flexibility and flexibility, is excellent in irradiation light quantity and uniform light leakage, and can be manufactured at low cost, and end face light leakage provided with the sheet-like light transmission body It is providing a type illumination device and a side light leakage type illumination device.

  As a result of intensive studies in view of the above problems, the present inventors have found that the above problems are solved in a sheet-like optical transmission body obtained by melt extrusion using a die having a slit-like discharge port. I found it.

That is, the present invention is a sheet-like optical transmission body having flexibility and flexibility in which the periphery of a core portion made of a transparent organic polymer is covered with at least one clad portion, and the sheet-like optical transmission The body is obtained by melt extrusion molding using a die having a slit-like discharge port, and when the sheet width of the sheet-like optical transmission body is L (mm) and the sheet thickness is d (mm) Formula (1),
5 ≦ L / d ≦ 40000, 0.05 ≦ d ≦ 1.0 (1)
Further, when the thickness of the clad portion of the sheet-like optical transmission body is b (mm), the general formulas (2), (3),
b ≦ d / 2−0.01 (2)
0.05 ≦ d ≦ 1.0, 0.002 ≦ b ≦ 0.25 (3)
It is related with the sheet-like optical transmission body characterized by being in the range.

  The present invention also includes a sheet-like light transmission body and a light source device optically connected to one end surface of the sheet-like light transmission body, and light incident on the sheet-like light transmission body from the light source device is a sheet. The present invention relates to an end face leakage type illumination device characterized in that light leaks from an end face on the opposite side of the one end face to which a light source device of a light transmission body is connected.

  Furthermore, the present invention provides a sheet-shaped optical transmission body in which a part of the surface of the clad portion on both the left and right sides of the sheet-shaped optical transmission body is roughened or the cladding portion is removed, and the sheet-shaped optical transmission body A light source device optically connected to at least one end of the light source, and light incident from the light source device leaks from the left and right side surfaces of the sheet-shaped optical transmission body that have been roughened or the cladding portion has been removed. The present invention relates to a side light leakage type illumination device.

  The sheet-like optical transmission body of the present invention can be manufactured at low cost, and has the characteristics of being flexible and flexible and excellent in translucency. Furthermore, the illumination device provided with the sheet-like optical transmission body can achieve a small size and light weight in addition to a large irradiation light amount and uniform light leakage.

  The sheet-like optical transmission body of the present invention is obtained by melt extrusion molding around the core part made of a transparent organic polymer using a die having a slit-like discharge port while covering at least one clad part. It is characterized by being able to.

  Although it does not specifically limit about die | dye which has said slit-shaped discharge port, After forming the layer structure which covers the circumference | surroundings of a transparent core material with one or more types of sheath materials, toward a slit-shaped discharge port A die or the like having a widened portion whose channel cross-sectional shape is gradually deformed and capable of discharging with a predetermined width and thickness while maintaining the layer structure is suitable. By using such a slit die, it becomes possible to shape while controlling the sheet thickness and the clad thickness thinly and uniformly.

  FIG. 1 is a cross-sectional view of a sheet-like optical transmission body of the present invention. The cladding (2) completely covers the periphery of the core (1).

  The structure of the sheet-like optical transmission body is in the range of L / d = 5-40000, d = 0.05 mm-1.0 mm, where L (mm) is the sheet width and d (mm) is the sheet thickness. Preferably, L / d = 7 to 10000, more preferably in the range of d = 0.1 mm to 1.0 mm, L / d = 10 to 1000, d = in the range of 0.2 mm to 0.8 mm More preferably it is.

  In particular, if d is smaller than 0.05 mm, it is not preferable because the strength of the sheet-shaped optical transmission body is insufficient. If d is larger than 1.0 mm, the sheet-shaped optical transmission body is insufficient in flexibility and flexibility. Although L / d is determined by d, if L / d is smaller than 5, the sheet-like optical transmission body cannot have a sufficient sheet width and cannot irradiate the wide range which is the object of the present invention. . Moreover, if L / d is larger than 40000, the molding stability of the sheet-like optical transmission body tends to be lowered.

Furthermore, when the thickness of the clad part (2) of the sheet-like optical transmission body is b (mm), as shown in FIG.
b ≦ d / 2−0.01 (10)
And 0.05 ≦ d ≦ 1.0 and 0.002 ≦ b ≦ 0.25 (11)
It is preferable that
0.1 ≦ d ≦ 0.9 and 0.005 ≦ b ≦ 0.1 (12)
More preferably,
0.2 ≦ d ≦ 0.8 and 0.01 ≦ b ≦ 0.05 (13)
More preferably, the relationship is

  If the thickness b of the clad part (2) is larger than d / 2−0.01, the core part becomes thin, so that a sufficient amount of light cannot be transmitted. Further, if L is smaller than 0.05, the stability of extrusion molding of the sheet-shaped optical transmission body is lowered, and if L is larger than 1.0, the sheet-shaped optical transmission cannot be provided with flexibility and flexibility. Further, if b is smaller than 0.002, light may easily leak from the clad, and if b is larger than 0.25, the function as the clad is sufficiently fulfilled, resulting in an increase in manufacturing cost.

  In the sheet-like optical transmission body of the present invention, the shape of the left and right end portions of the core portion is rectangular (a), substantially rectangular (b), triangular (c), and convex as shown in FIG. It is possible to take the shape of (d) etc., but in order for the sheet-like optical transmission body to have long-distance optical transmission properties, it is particularly a convex shape, and is substantially semicircular or substantially semielliptical. It is preferable that it is formed from a part of. By making the shape of both side end portions of the core portion a part of a substantially semicircular shape or a substantially semi-elliptical shape, it is possible to suppress light from leaking from the end portion of the core portion of the sheet-like optical transmission body. Become.

Furthermore, in the sheet-like optical transmission body of the present invention, when the shape of both side ends of the core portion can be approximated by a part of a substantially semicircular shape, the radius of curvature R is as shown in FIG. Following formula (14)
a / 2 ≦ R ≦ a (14)
It is preferable that the relationship is

Alternatively, when the shape of the both end portions of the core portion of the sheet-like optical transmission body can be approximated by a part of a substantially semi-elliptical shape, the radius of curvature at the end point of the core portion as shown in FIG. R is
a / 8 ≦ R ≦ 4 × a (15)
It is preferable that the relationship is

In the sheet-like optical transmission body of the present invention, the amount (g / 10 minutes) of polymer discharged in 10 minutes from a nozzle having a diameter of 2 mm and a length of 8 mm under the condition of a load of 5 kgf (49 N) at the molding temperature is melted. When the flow rate (MFR) is set, M1 of the material of the core part of the sheet-like optical transmission body is M1, and MFR of the material of the clad part is M2, the following formula (16)
M1 <M2 (16)
It is preferable that the relationship is Here, the molding temperature means the temperature of the slit die. When the relationship of M1 <M2 is satisfied, as described above, it becomes easy to make the shape of the end of the core portion into a substantially semicircular shape or a substantially semielliptical shape. When M1 ≧ M2, it becomes difficult to control the shape of the end of the core part, and it is difficult to obtain a sheet-like optical transmission body in which the cladding part is thinly coated with a uniform thickness. There is a fear.

In the sheet-shaped optical transmission body of the present invention, the refractive index of the core portion of the sheet-shaped optical transmission body measured at 25 ° C. with sodium D line is n ₁ , and the number of cladding layers is m. When the refractive index of the clad is n ₂ , the refractive index of the clad of the second layer is n ₃ , and the refractive index of the clad of the mth layer is _{nm + 1} , the following formulas (17) and (18)
n ₁ > n ₂ > n ₃ >...> n _m > n _{m + 1} (17)
(N ₁ ² −n _{m + 1} ² ) ^1/2 ≧ 0.40 (18)
It is preferable to satisfy.

  The causes of light leakage from the sheet side surface of the sheet-like optical transmission are due to cracking of the clad (insufficient strength) and the like, optical characteristics of the clad itself, and structural characteristics of the POF (numerical aperture, between core and clad) Structural irregularities, macro bending, micro bending, etc.).

By satisfying the equation (17), that is, the refractive index of the first-layer cladding from the core is n ₂ , the refractive index of the second-layer cladding is n ₃ , and the refractive index of the _m- th cladding is n _{m + 1.} In this case, the light leaked from the first clad when the sheet-like optical transmission is bent by satisfying the relationship of n ₁ > n ₂ > n ₃ >...> N _m > n _{m + 1} Can be reflected by the second cladding, light leakage from the side surface when the sheet-like light transmission is bent can be reduced, and use at a long distance is possible.

In addition, with regard to Expression (18), if (n ₁ ² −n _{m + 1} ² ) ^1/2 is less than 0.40, the amount of bending loss when the sheet-like optical transmission is bent can be sufficiently reduced. May be difficult. In order to set (n ₁ ² −n _{m + 1} ² ) ^1/2 to the above value, the refractive index n _{m + 1} of the outermost cladding may be appropriately selected according to the refractive index n ₁ of the core. For example, when the core portion is polymethyl methacrylate (n ₁ = 1.492) and the clad portion is one layer, the clad refractive index n ₂ is 1.437 or less ((n ₁ ² −n _{m + 1} ² ) ^{1. / 2} is preferably 0.4), more preferably 1.406 or less (0.5), and even more preferably 1.366 or less (0.6).

  A known material can be used as the material of the core portion of the sheet-like optical transmission body of the present invention. For example, methyl methacrylate homopolymer (PMMA) or copolymer, polystyrene resin, polycarbonate resin, cyclic An organic (co) polymer selected from polyolefin resins can be used as a main component.

  In addition, when using the copolymer of methyl methacrylate, it is preferable that content of a methyl methacrylate unit shall be 50 mass% or more. Examples of the copolymerizable monomer include acrylic acid esters such as methyl acrylate, ethyl acrylate, and n-butyl acrylate, and methacrylates such as ethyl methacrylate, propyl methacrylate, and cyclohexyl methacrylate, Examples include maleimides, acrylic acid, methacrylic acid, maleic anhydride, and styrene.

  Among these, it is preferable to configure PMMA as a main component because it is excellent in translucency and durability and is inexpensive.

  As the resin for forming the first clad layer, a known material used as a clad material for POF may be appropriately selected according to the use environment or purpose of use of the sheet-like optical transmission body. A fluorinated methacrylate-based polymer and a vinylidene fluoride-based polymer having a refractive index and excellent transparency and heat resistance are preferred.

As the fluorinated methacrylate polymer, more specifically, the following general formula (I)
_{CH 2 = CX-COO (CH} 2) m (CF 2) n Y (I)
(In the formula, X represents a hydrogen atom or a methyl group, Y represents a hydrogen atom or a fluorine atom, m represents 1 or 2, and n represents an integer of 1 to 12.)
And a copolymer comprising 15 to 90% by mass of the unit (A) of fluoroalkyl (meth) acrylate represented by the formula (10) and 10 to 85% by mass of another copolymerizable monomer unit (B). it can.

  As the unit (A) of fluoroalkyl (meth) acrylate, (meth) acrylic acid-2,2,2-trifluoroethyl (3FM), (meth) acrylic acid-2,2,3,3-tetrafluoropropyl (4FM), (meth) acrylic acid-2,2,3,3,3-pentafluoropropyl (5FM), (meth) acrylic acid-2,2,3,4,4,4-hexafluorobutyl (6FM) ), (Meth) acrylic acid-1H, 1H, 5H-octafluoropentyl (8FM), (meth) acrylic acid-2- (perfluorobutyl) ethyl (9FM), (meth) acrylic acid-2- (perfluoro) (Hexyl) ethyl (13FM), (meth) acrylic acid-1H, 1H, 9H-hexadecafluorononyl (16FM), (meth) acrylic acid-2- (perfluorooctyl) Linear chain such as ethyl (17FM), (meth) acrylic acid-1H, 1H, 11H- (icosafluoroundecyl) (20FM), (meth) acrylic acid-2- (perfluorodecyl) ethyl (21FM) (Meth) acrylic acid fluorinated ester having a fluorinated alkyl group in the side chain.

  Although it does not specifically limit as said other copolymerizable monomer unit (B), A methyl (meth) acrylate unit is used for improving transparency, and (meth) acrylate is used for improving mechanical properties. , (Meth) acrylic acid alkyl ester units such as (meth) butyl acrylate, (meth) acrylic acid cyclohexyl, (meth) acrylic acid methyl cyclohexyl, (meth) acrylic acid bornyl, (meta) ) Units of (meth) acrylic acid cycloalkyl esters such as isobornyl acrylate and adamantyl (meth) acrylate, units of (meth) acrylic acid aromatic esters such as phenyl (meth) acrylate and benzyl (meth) acrylate, Units of hexafluoroneopentyl (meth) acrylate, N-methylmaleimide, N-ethylmaleimide, N-pro N-substituted maleimide units such as lumaleimide, N-isopropylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, α-methylene-γ-butyrolactone, α-methylene-γ-methyl-γ-butyrolactone, α-methylene-γ Units of γ-butyrolactone compounds such as γ-dimethyl-γ-butyrolactone, α-methylene-γ-ethyl-γ-butyrolactone, α-methylene-γ-cyclohexyl-γ-butyrolactone, and the like can be used.

  On the other hand, a vinylidene fluoride polymer not only has a low refractive index and excellent transparency and heat resistance, but also as a protective layer for the inner cladding layer or core, while maintaining adhesion, It is particularly preferable as a material having a function of relaxing the stress such as vibration and external pressure to increase the bending resistance of the sheet-form optical transmission body and improving the solvent resistance and chemical resistance. Tetrafluoroethylene ( Examples thereof include copolymers obtained by copolymerizing at least one of TFE) units, hexafluoropropylene (HFP) units, perfluoro (fluoro) alkyl vinyl ether (FVE) units, and hexafluoroacetone units. It is not limited to. As the copolymer component with the VdF unit, the TFE unit, the HFP unit, and the FVE unit are particularly preferable because the copolymer formed using the VdF unit is excellent in transparency and heat resistance as a clad. preferable.

As a specific example of the vinylidene fluoride polymer,
From binary copolymer which consists of 60-90 mass% of VdF units and 10-40 mass% of TFE units, 10-60 mass% of VdF units, 20-70 mass% of TFE units, and 5-35 mass% of HFP units. A terpolymer comprising 5 to 25% by mass of VdF units, 50 to 80% by mass of TFE units, 5 to 25% by mass of FVE units, 10 to 30% by mass of VdF units, and TFE. The quaternary copolymer which consists of 40-80 mass% of units, 5-40 mass% of HFP units, and 0.1-15 mass% of FVE units can be mentioned.

The above-mentioned “FVE unit” means the general formula (IV)
_{CF 2 = CF- (OCF 2 CF} (CF 3)) a O-Rf2 (IV)
(In the formula, Rf2 represents an alkyl group having 1 to 8 carbon atoms, a fluoroalkyl group, an alkoxylalkyl group or a fluoroalkoxylalkyl group, and a is an integer of 0-3.)
More specifically, the following general formulas (V) to (VIII)
_{CF 2 = CFO (CF 2)} n -OCF 3 (V)
(Where n is an integer from 1 to 3)
_{CF 2 = CF (OCF 2 CF} (CF 3)) n O (CF 2) m CF 3 (VI)
(Where n is an integer from 0 to 3, m is an integer from 0 to 3)
CF ₂ ═CFO (CH ₂ ) _n (CF ₂ ) _m CF ₃ (VII)
(Where n is an integer from 1 to 3, m is an integer from 0 to 3)
CF ₂ = CFO (CH ₂ ) _n CH ₃ (VIII)
(Where n is an integer from 0 to 3)
It is preferable that it is a unit of the compound represented by either.

Among _{these, CF 2 = CFOCF 3, CF} 2 = CFOCF 2 CF 3, CF 2 = CFOCF 2 CF 2 CF 3, CF 2 = CFOCH 2 CF 3, CF 2 = CFOCH 2 CF 2 CF 3, CF 2 = If it is a unit of at least one compound selected from the group consisting of CFOCH ₂ CF ₂ CF ₂ CF ₃ , CF ₂ = CFOCH ₃ , CF ₂ = CFOCH ₂ CH ₃ and CF ₂ = CFOCH ₂ CH ₂ CH ₃ , It is more preferable from the viewpoint that the cost of the raw material can be reduced.

  Further, in order for the vinylidene fluoride polymer to have sufficient transparency and heat resistance as a cladding material, it is preferable that the heat of crystal melting in differential scanning calorimetry (DSC) is in the range of 10 to 80 mJ / mg. It is preferably in the range of 20-70 mJ / mg, more preferably in the range of 40-60 mJ / mg.

  The heat of crystal melting is the amount of heat generated due to the heat melting of the fluorine-containing olefin resin, and the greater the amount of heat, the greater the crystallinity of the fluorine-containing olefin resin and the lower the transparency. Conversely, the smaller the amount of heat, the lower the crystallinity and the better the transparency. More specifically, when the amount of heat is greater than 80 mJ / mg, the clad material tends to become cloudy. When such a resin is used for the clad layer, the optical transmission performance of the sheet-like optical transmission body is lowered. In addition, when exposed to a high temperature environment for a long period of time, the optical transmission performance of the sheet-like optical transmission body tends to be remarkably increased. From the viewpoint of suppressing the increase in transmission loss more sufficiently, it is preferable to use a resin having a heat of crystal melting of 80 mJ / mg or less, and more preferably 65 mJ / mg or less. On the other hand, when the amount of heat is less than 10 mJ / mg, the heat resistance of the clad material tends to decrease, and when exposed to a high temperature environment for a long time, the optical transmission performance of the sheet-like optical transmission body is remarkably increased. There is a tendency.

  The sheet-shaped optical transmission body of the present invention can be further coated with a protective layer on the outer side of the cladding in order to improve bending resistance, moist heat resistance, moist heat resistance, chemical resistance, and cut resistance. As this protective layer, a material having a Shore D hardness (ASTM D2240) of 50 or more is preferable.

  Specific examples of such a protective layer material include a methyl methacrylate homopolymer (PMMA) or copolymer, a polystyrene resin, a polycarbonate resin, and the like. Alternatively, a copolymer containing at least one of a VdF unit and a TFE unit and having a content of 60% by mass or more can be given, for example, a VdF / TFE copolymer, a VdF / HFA copolymer, a VdF, or the like. / HFP copolymer, VdF / TFE / HFP copolymer, VdF / TFE / HFA copolymer, TFE / HFP copolymer, ethylene / TFE / HFP copolymer, etc., but are not limited thereto. It is not a thing.

  The method for forming the protective layer is not particularly limited, and a dip coating method may be used if there is a soluble solvent. Alternatively, if the material for the protective layer, the core material, and the clad material can be molded at the same temperature, they may be co-extruded from a slit die. Alternatively, once a core-clad structure sheet-shaped optical transmission body is formed in advance, a protective layer may be coated on the outer periphery of the sheet-shaped optical transmission body using a coating apparatus using a crosshead die. .

In addition, in order to give the sheet-like light transmission body of the present invention moderate soft flexibility and mechanical strength, or to suppress dimensional deformation when the sheet-like light transmission body is left in a high temperature environment, When the sheet-shaped optical transmission body is left in a thermostat at 150 ° C. for 20 minutes, when the yarn diameter before heat treatment is d ₁ and the yarn diameter after heat treatment is d ₂ , the following formula (19),
D = (d ₂ / d ₁ ) ² (19)
The stretching ratio D calculated from the above is preferably 1.0 to 3.0, and more preferably 1.4 to 2.5 or less. If the stretching ratio is less than 1.0, the mechanical strength of the sheet-shaped optical transmission body is insufficient, so that the sheet-shaped optical transmission body is stored in a state of being wound around a bobbin, or the sheet-shaped optical transmission body is bent. There is a possibility that it sometimes breaks easily. This is because if the stretch ratio is larger than 3.0, the sheet-like optical transmission body may be thermally contracted and the optical transmission performance may be deteriorated when the sheet-like optical transmission body is used at around 100 ° C.

  Moreover, it is preferable that the sheet-form optical transmission body of this invention has a side edge part with a thickness of 0.5 mm or more formed from a clad layer in the right and left both ends of the sheet-form optical transmission body. Here, the width of the side edge portion formed from the clad layer means c in FIG. Normally, in sheet extrusion using a slit die, the pressure loss near the both ends of the slit is large. Therefore, as the thickness of the sheet decreases, the shape of the end of the sheet becomes more stringent, the width of the sheet, There is a tendency for molding stability to decrease, for example, the thickness varies. However, according to the study by the present inventors, when the thickness of the sheet is thin by providing side edge portions formed from the clad layer on the left and right side end portions of the sheet-like optical transmission body at a width of 0.5 mm or more. However, it becomes possible to mold stably.

   On the other hand, in the sheet-like optical transmission body of the present invention, when light is incident, there may occur a phenomenon in which the luminance of the side edge portions of the left and right side end portions is noticeably higher than the luminance of the central portion of the sheet. When the phenomenon occurs, there is a possibility that the use as a lighting body may be hindered. There are two ways to solve this problem.

   In the first method, after obtaining the sheet-like optical transmission body by extrusion molding according to the method described above, the width (c) of the side edge portion having a width of 0.5 mm or more is deleted by an appropriate method, In this method, 0.002 ≦ c <0.5. When the width (c) of the side edge portion is larger than 0.5 mm, the effect of reducing the luminance of the side edge portion is insufficient, and when it is smaller than 0.002 mm, the light is more concentrated than the portion. May leak. A more preferable range of the width (c) of the side edge portion is 0.01 ≦ c <0.2, and a more preferable range is 0.02 ≦ c <0.1.

  The second method is a method of providing a coating resin layer or a coating layer having a light shielding effect (hereinafter referred to as “light shielding coating layer”) on the outer periphery of the side edge portion. Specifically, a black paint can be applied and coated on the outer periphery of the side edge portion, or a method of coating a blackened thermoplastic resin or ultraviolet curable resin with carbon black or the like can be exemplified. It is not particularly limited. The thickness of the light shielding coating layer is not particularly limited, and may be set as appropriate so as to have a thickness that has at least a light shielding effect and does not hinder use as a sheet-like optical transmission body.

  Hereinafter, an illuminating device having the sheet-like optical transmission body of the present invention will be described in detail.

  An illuminating device having a sheet-like light transmission body of the present invention is roughly composed of a resin material core, a sheet-like light transmission body, and a light source device optically connected to at least one end of the sheet-like light transmission body. The light incident from the light source device is illuminated by leaking light from the end or side surface of the sheet-like optical transmission body.

  For example, a light source device is optically connected to one end surface of the sheet-like optical transmission body, and an end face leakage type illumination device that leaks light from one end surface opposite to the side to which the light source device is connected is used. it can.

  Alternatively, a side light leakage type illumination device in which a light source device is optically connected to at least one end surface of the sheet-like light transmission body and light is leaked from a side surface portion of the sheet-like light transmission body can be provided.

  When used as the above-mentioned side light leakage type illumination device, in order to leak light from the desired side surface portion of the sheet-like light transmission body to the outside, a part of the surface of the left and right side surface portions of the sheet-like light transmission body is roughened. It is necessary to perform a treatment such as removing the cladding portion forming the side surface portion.

  Specifically, a method in which a part of the side surface of the sheet-like light transmission body is melted and surface heat-treated, a chemical blasting method in which the surface of the sheet-like light transmission body is dissolved by chemical or electrochemical treatment, It is possible to use a shot blasting method in which an abrasive material or a similar material is vigorously struck against the surface of the sheet-like optical transmission body.

  As for the surface heat treatment method, a conventional heating and melting method, for example, a method in which only a side surface portion where light leakage of a sheet-like optical transmission body is desired is heated in a heating furnace or is melted by pressing a hot plate. Can do. In this case, since it becomes easy to generate bubbles in the sheet-like optical transmission body during the heat treatment, it is necessary to perform the heat treatment under vacuum conditions.

  Examples of other surface heat processing methods include heat generation cutting methods such as laser cut processing, ultrasonic cutter processing, and hot cutter processing. In the case of these processing methods, for example, laser cutting, there is an advantage that the clad portion can be cut easily and precisely by adjusting the focus and output of the laser according to the material of the sheet-like optical transmission body and the thickness of the sheet.

  For shot blasting, drilling surface with fine powder such as glass, alumina, steel, silica sand, magnetite, and gold sand using abrasives (blasting material) and high pressure water and compressed air from a small nozzle connected to the compressor. A typical example is a sand blasting method in which the surface is polished by spraying. Compared to surface heat treatment and chemical blasting, shot blasting (especially sand blasting) is capable of roughening without damaging the sheet-like optical transmission body composed of organic polymers. Therefore, it is particularly preferable as a method for processing a sheet-like optical transmission body in the present invention.

  The light source device used in the illumination device having the sheet-like light transmission body of the present invention is used by being optically connected to at least one end face of the sheet-like light transmission body. Moreover, the form which connects and uses a light source device to the both ends of a sheet-like optical transmission body may be sufficient.

The light source device preferably has a plane located at a distance L1 from the emission end of the light source as the plane H, the center point of the irradiation spot on the plane H as the point P1, and the distance from the center point P1 of the irradiation spot on the plane H. If L2 is the point P2 and the point where the luminance is 50% of the luminance at the point P1 is the point P2, the following equation (20)
NA = sin {tan ⁻¹ (L 1 / L 2)} (20)
It is desirable to use a light source that satisfies an aperture angle NA of the light source defined by

  If NA <0.15, a sufficient amount of light cannot be uniformly supplied to the entire surface of the sheet-like light transmission body connected to the light source device, and a special portion is connected to the connection portion between the sheet-like light transmission body and the light source. There is a problem that it is necessary to install parts or to perform post-processing, which makes it difficult to reduce the size of the lighting device or to increase costs due to post-processing. Moreover, in an extreme case, incident light may propagate like a single line in the sheet-like light transmission body and may not function as an illuminating body, which is not preferable as a light source for an illumination device system. .

  Specifically, a metal halide lamp, a xenon lamp, a high-pressure mercury lamp, a light emitting diode (LED), or a semiconductor laser (LD) having a particularly high luminance is used as the light source device. In addition, it can change suitably according to application purposes, such as mounting | wearing of a reflective mirror and a lens, a lamp shape, and power consumption. When the light source is a highly directional semiconductor laser (LD), a lens having an aperture angle NA of 0.15 or more may be installed between the sheet-like optical transmission body and the LD.

  Among the above light sources, in particular, light emitting diodes (LEDs) can suppress the temperature rise around the light source even when lit for a long time, and thus prevent thermal deterioration and melting of the incident end of the sheet-like optical transmission body. Therefore, it can be said to be particularly preferable as the light source of the lighting device of the present invention.

  When an LED is used as the light source, at least one end of the sheet-like optical transmission body may be provided with one LED at the center of the end as shown in FIG. In order to reduce the light leakage spot of the light transmission body and increase the light leakage amount of the sheet-like light transmission body, two LEDs are installed at the side edge of the end face as shown in FIG. 6B. Alternatively, a method of introducing the incident light of the LED into the sheet type optical transmission body may be used.

  The sheet-like light transmission body of the present invention obtained as described above has flexibility and flexibility, and the illumination device provided with the sheet-like light transmission body is excellent in irradiation light quantity and uniform light leakage, small and lightweight. Because it is possible to design the device, it can be used for sensor applications such as sheet and paper pinhole detection applications, personal computer displays and keyboards, mobile phone screens, LCD panels, and touch panel control backlight applications. Is preferred.

  Hereinafter, the present invention will be described by way of examples. In addition, about the evaluation method in the Example of this invention, it implemented by the following method.

(Crystal melting heat (ΔH))
A differential scanning calorimeter (DSC) (manufactured by Seiko Instruments Inc., DSC-220) was used for the measurement. The sample was heated to 200 ° C. at a rate of temperature increase of 10 ° C./min, held in that state for 5 minutes and melted, and then cooled to 0 ° C. at a rate of temperature decrease of 10 ° C./min. This operation was repeated again, and the heat of crystal melting at this time was determined.

(Refractive index)
A 200 μm thick film specimen was formed by a melt press, and the refractive index (nD25) of sodium D line at 25 ° C. was measured using an Abbe refractometer.

(Melt flow rate)
The melt flow rate (MFI) was measured according to Japanese Industrial Standard JIS K7210. The amount of polymer (g / 10 minutes) discharged in 10 minutes from a nozzle having a diameter of 2 mm and a length of 8 mm under the conditions of 210 ° C. and a load of 5 kgf (49 N) was measured.

(Stretch rate)
When the sheet-shaped optical transmission body is left in a constant temperature bath at 150 ° C. for 20 minutes, when the yarn diameter before heat treatment is d1 and the yarn diameter after heat treatment is d2, (drawing ratio) = (d2 / d1) 2 Calculated.

(Example 1)
In the apparatus configuration shown in FIG. 7, a sheet was manufactured. As the nozzle, a nozzle having a widened portion with a slit-like discharge port width of 40 mm and a thickness of 0.5 mm downstream of the nozzle that joins the core material and the clad material to form a two-layer structure was used. A polishing roll was used as the cooling roll, and the roll gap was 0.4 mm, which was slightly thinner than the discharge port thickness.

  PMMA (manufactured by Mitsubishi Rayon Co., Ltd., Acrypet, MFR = 2.4, refractive index 1.492) is used for the core material constituting the sheet, and VP-50 (Daikin Industries, Ltd.) is used for the sheath material. Manufactured, VdF / TFE = 80/20 mol%, MFR = 15.2, refractive index 1.402, heat of crystal fusion 59 mJ / mg). The operating conditions of the extruder were standard conditions for each resin. The nozzle temperature was 230 ° C. to produce a sheet. The obtained sheet had a width of 40 mm and a thickness of 0.4 mm, and when the cross section was observed, it was a two-layer structure in which the cladding material was uniformly covered around the core material, and the shape of the side end of the core portion was approximately half It was elliptical. Further, the thickness of the clad material was 45 μm, and the thickness was uniform in any part of the cross section. Further, side edge portions having a width of 3 mm were formed at both left and right end portions of the sheet-like material. The stretch ratio of this sheet-like product was measured to be 1.1. After sufficiently polishing the end face of the obtained sheet-like material (sheet length 1 m), when the light from the LED light source (opening angle NA = 0.17) is incident from one end face, the end face leakage type is emitted uniformly from the other end face. It was a sheet-like optical transmission body.

(Example 2)
VP-2000 (manufactured by Daikin Industries, Ltd., VDF / TFE / HFP = 48.0 / 42.7 / 9.3 (wt%)), MFR = 45, refractive index 1.374, heat of crystal melting 16 mJ / Mg), a sheet was produced under the same conditions as in Example 1. The obtained sheet had a width of 30 mm and a thickness of 0.3 mm, and the cross-section was observed. As a result, the clad material uniformly covered the periphery of the core material, and the shape of the side end of the core portion was approximately half. It was elliptical. Further, the thickness of the clad material was 32 μm, and the thickness was uniform in any part of the cross section. Further, side edge portions having a width of 2 mm were formed at both left and right end portions of the sheet-like material. The stretch ratio of this sheet was measured and found to be 1.3.

  After the end surface of the obtained sheet-like material (sheet length 1 m) was sufficiently polished, when the light from the LED light source was incident from one end surface, it was an end face leakage type sheet-like optical transmission body that uniformly emitted from the other end surface.

Example 3
Except for using LJ-202042 (manufactured by Sumitomo 3M Co., Ltd., VDF / TFE / HFP / FVE copolymer, MFR = 21, refractive index 1.350, heat of crystal melting 16 mJ / mg) for the clad material A sheet was produced under the same conditions as in Example 1. The obtained sheet had a width of 20 mm and a thickness of 0.35 mm, and its cross section was observed. As a result, the clad material uniformly covered the periphery of the core material, and the shape of the end of the core portion was substantially semi-elliptical. It was a shape. Further, the thickness of the clad material was 20 μm, and the thickness was uniform in any part of the cross section. Further, side edge portions having a width of 1 mm were formed at both left and right end portions of the sheet-like material. The stretching ratio of this sheet-like product was measured to be 2.0.

  After sufficiently polishing the end face of the sheet-like material (sheet length 1 m) obtained in this way, when the light from the LED light source is incident from one end face, the end face light leakage type sheet-like light transmission body is emitted uniformly from the other end face. Met.

Example 4
The core portion was exposed by performing a surface roughening treatment using a sandblasting method in a range of about 40 mm in the center of the sheet of the sheet-like optical transmission body (sheet length 1 m) manufactured in Example 1. When one LED light source (two in total) is installed in the center part of the end surfaces of both ends of this sheet-like optical transmission body and light is incident, the light is concentrated from the roughened part to the outside. It was a side light leakage type sheet-like optical transmitter that leaked light.

(Example 5)
The sheet-like optical transmission body (sheet length 1 m) produced in Example 4 was subjected to a surface roughening process using the sand blasting method under the same conditions as in Example 4 to expose the core part. When one LED light source is installed at both corners of the both ends of the sheet-like optical transmission body (two at one end, a total of four) and light is incident, it is concentrated from the roughened portion. It was a side light leakage type sheet-like optical transmission body in which light was emitted to the outside, and the light leakage amount was larger than that in Example 4.

(Example 6)
In the sheet-like optical transmission body (sheet length: 1 m) manufactured in Example 4, a light-shielding coating layer is provided by applying black paint so as to completely cover the side edge portions having a width of 3 mm at both left and right end portions. It was. The light from the LED light source was incident on the sheet-like light transmission body in the same manner as in the fourth embodiment. Before providing the light-shielding coating layer, the amount of leakage from the side edge portion of the sheet-like optical transmission body was a level that cannot be ignored with respect to the amount of leakage from the portion subjected to the roughening treatment, By providing the light-shielding coating layer, it was possible to extract only light leakage from the roughened portion.

  Since the sheet-like light transmission body of the present invention has flexibility and flexibility, and the illumination device equipped with the sheet-like light transmission body is excellent in small size and light weight, irradiation light quantity and uniform light leakage, and more inexpensive. Because it can be manufactured, its applications include sensor applications such as sheet and paper pinhole detection applications, personal computer displays and keyboards, mobile phone screens, LCD panels, and touch panel control backlight applications. The range of use is very wide in industry.

It is the schematic diagram which showed sectional drawing of the sheet-like optical transmission body. It is the schematic diagram which showed the range of the sheet thickness and clad thickness of a sheet-like optical transmission body. It is the schematic diagram which showed the shape of the core part edge part of a sheet-like optical transmission body. It is the schematic diagram which showed that the shape of the side edge part of the core part of the sheet-like optical transmission body of a sheet-like optical transmission body approximated by a part of substantially semicircle shape. It is the schematic diagram which showed that the shape of the side edge part of the core part of a sheet-like optical transmission body approximated by a part of substantially semi-elliptical shape. It is a schematic diagram which shows arrangement | positioning of LED in the case of using (a) and using two LED (b) in one end part of a sheet-like optical transmission body using one LED. It is a schematic diagram which shows an example of the manufacturing process of this embodiment (Examples 1-4).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Core part 2 ... Cladding part a ... Core part thickness b ... Cladding part thickness L ... Sheet width d ... Sheet thickness R ... Curvature radius

Claims (4)

A method for producing a flexible flexible sheet-shaped optical transmission body, in which the periphery of a core portion made of a transparent organic polymer is covered with at least one clad portion,
A sheet-like light satisfying the following condition, which is manufactured by melt extrusion using a die having a slit-like discharge port under the condition that the MFR of the core part material is smaller than the MFR of the clad part material A method of manufacturing a transmission body.
When the sheet width of the sheet-shaped optical transmission body is L (mm) and the sheet thickness is d (mm), the general formula (1),
5 ≦ L / d ≦ 40000, 0.05 ≦ d ≦ 1.0 (1)
Further, when the thickness of the clad portion of the sheet-like optical transmission body is b (mm), the general formulas (2), (3),
b ≦ d / 2−0.01 (2)
0.05 ≦ d ≦ 1.0, 0.002 ≦ b ≦ 0.25 (3)   The sheet-like optical transmission body has side edge portions formed from clad layers on both left and right ends, and when the thickness of the side edge portion is c (mm), 0.5 ≦ c. The manufacturing method of the sheet-like optical transmission body of Claim 1.   The width of the side edge portion formed from the clad layers at the left and right end portions of the sheet-like optical transmission body is 0.002 ≦ c <0.5, where c (mm). A manufacturing method of the sheet-like optical transmission body according to 1. 4. The sheet-like optical transmitter according to claim 2, further comprising a light-shielding coating layer provided on an outer periphery of a side edge portion formed from a clad layer at both left and right end portions of the sheet-like optical transmitter. Manufacturing method .

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