JP2012164576A - Light guide sheet and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem wherein light volume of an illuminated region becomes insufficient since the illuminated region can not be illuminated uniformly with reflected light of a shape reflecting a shape of recessed sections due to close approach between the recessed sections and the illuminated region, when applying an illumination mechanism having a plurality of recessed sections on a light guide sheet to a small portable terminal device such as a mobile phone.SOLUTION: In the light guide sheet 1 wherein a plurality of recessed sections 1b are arranged on at least one surface of the light guide sheet 1 for propagating light from an external light source and the propagated light is emitted by being reflected at the plurality of recessed sections 1b, indefinite projected shapes 1c are arranged on the plurality of recessed sections 1b. Thus, a part of light L1 among the light propagated through the light guide sheet 1 is directly emitted from the projected shapes 1c of the recessed sections 1b in many directions, and a part of light L2 is emitted after being reflected with the projected shapes 1c at indefinite shapes, and the illuminated region 11a can be uniformly illuminated even when the recessed sections 1b of the light guide sheet 1 and the illuminated region 11a are closely approached each other in the thin illumination mechanism.

Description

  The present invention relates to a light guide sheet mainly used for operation of various electronic devices and a method for manufacturing the light guide sheet.

  In recent years, in various electronic devices, particularly mobile terminal devices such as mobile phones, even if the surroundings are dark, the operation unit is illuminated by emitting light such as a light emitting diode so that operation buttons can be easily identified and operated. Things are increasing. In such illumination by a light emitting diode or the like, illumination mechanisms having various structures have been proposed in order to efficiently reflect the light from the light emitting diode or the like and effectively illuminate the operation unit.

  As shown in FIG. 9, the illumination mechanism described in Patent Document 1 includes a membrane laminate 120 laminated on the chassis 102 and a key top 124 laminated on the membrane laminate 120. The membrane laminate 120 is formed of a substrate sheet 121, a pressing sheet 122, and a spacer layer 123 composed of an organic resin layer 123a and an adhesive layer 123b. An upper contact 126 is provided on the lower surface of the pressing sheet 122, and the substrate sheet A lower contact 125 is provided on the upper surface of 121. The pressing sheet 122 is deformed when the user depresses the key top 124 and has a function of bringing the upper contact 126 and the lower contact 125 into contact and conduction, and also functions as a light guide sheet. In the reflective region 127 facing each other, a plurality of recesses 128 are provided on the back surface 122 a of the pressing sheet 122.

  The light emitted from the light emitting diode device 129 propagates through the pressing sheet 122, is reflected upward by the inner surface of the recess 128, and is given to the key top 124.

  According to Patent Document 1, the recess 128 formed in the pressing sheet 122 is formed by disassembling a part of the synthetic resin material that forms the pressing sheet 122 by the energy of laser light. Since the inner surface of the recess 128 is a smooth surface, that is, a mirror surface, the light propagating inside the pressing sheet 122 hits the inner surface of the recess 128 inside the pressing sheet 122. In addition, light is not diffusely reflected on the inner surface, and is reflected in the sheet according to the principle of incident angle and reflection angle according to the angle of the inner surface.

  For this reason, in said illumination mechanism, since the light which propagates the press sheet | seat 122 is reflected by the inner surface of the smooth recessed part 128, reflected light becomes a shape reflecting the shape of the recessed part 128. FIG.

  In the case of an illuminating device used in a keyboard device as disclosed in Patent Document 1, there is a sufficient distance between the concave portion and the key top, so even if the reflected light has a shape reflecting the shape of the concave portion, the position of the keyboard With uniform illumination, the light from the light source can be efficiently applied to the key tops, and the illuminated parts of each key top can be clearly illuminated, and the recesses are formed by decomposing the material with the energy of the laser light. Therefore, the recess can be manufactured easily and efficiently.

JP 2010-218995 A

  However, when the illumination mechanism as shown in Patent Document 1 is applied to a portable terminal device such as a mobile phone that is much smaller and thinner than a keyboard, the shape of the recess is formed because the portable terminal device is thin and the recessed portion and the illuminated portion are close to each other. The reflected light having a shape reflecting the above cannot illuminate the illuminated part uniformly, and there is a problem that the quantity of light in the illuminated part is insufficient.

  This invention is made | formed in view of the said situation, The objective is to provide the manufacturing method of the light guide sheet and light guide sheet which illuminate an illumination part uniformly also with a thin illumination mechanism.

  In order to achieve the above object, in the light guide sheet of the present invention, a main body portion that propagates light from an external light source, and a plurality of concave portions are provided on at least one surface of the main body portion, and the propagated light is the plurality of light rays. In the light guide sheet that emits light from the main body portion by being reflected by the concave portions, at least one of the plurality of concave portions is provided with a protrusion-shaped portion.

  Thereby, since the projection-shaped portion is provided in the concave portion provided on the surface of the main body portion that propagates light, the light propagating through the light guide sheet is reflected by the plurality of concave portions and is emitted from the main body portion. Part of the propagated light is emitted directly in multiple directions from the protrusion-shaped part provided in the recess, and part of it is irregularly reflected by the protrusion-shaped part and exits from the main body part. Even when the illuminated parts are close to each other, the illuminated parts can be illuminated uniformly.

  In the light guide sheet according to the present invention, the protrusion-shaped portion is provided on the upper end side of the recess.

  As a result, since the protrusion-shaped part is provided on the upper end near the outside, the protrusion-shaped part and the illuminated part are closer to each other, and the light directly emitted from the protrusion-shaped part efficiently illuminates the illuminated part. can do.

  The light guide sheet according to the present invention is characterized in that a plurality of the protrusion-shaped portions are provided in the recess.

  As a result, a plurality of protrusion-shaped portions are provided in the recess, so that the light directly emitted from the plurality of protrusion-shaped portions and the light output after being reflected by the plurality of protrusion-shaped portions also become a plurality of light from the light guide sheet. The amount of emitted light can be improved.

  The light guide sheet according to the present invention is characterized in that the plurality of protrusion-shaped portions are indefinite.

  As a result, a plurality of irregular shaped protrusions are provided in each recess, so that light directly emitted from the plurality of irregularities and light diffused and diffused by the plurality of irregularities are also irregular. Since the light is superimposed and emitted, the light emitted from the light guide sheet is not uneven as a whole, and the illuminated portion can be illuminated more uniformly.

  Further, the light guide sheet according to the present invention is characterized in that the main body portion is mainly made of polycarbonate resin.

  Since polycarbonate is highly transparent, the light guide sheet's main body is made of polycarbonate resin, allowing light to propagate through the light guide sheet without loss and increasing the amount of light emitted from the illuminated part. Can be improved.

  In addition, the light guide sheet manufacturing method according to the present invention includes applying a halogen compound to the surface of the main body of the light guide sheet and irradiating laser light to form a recess in the surface, and the recess has an indefinite shape. A protrusion-shaped part is formed.

  As a result, by forming a halogen compound film on the surface of the light guide sheet in advance, it is possible to create an irregularly shaped protrusion in the recess at the same time as the recess formation by laser light. There is no need to add a process, and the protrusion-shaped portion can be reliably created without shifting into the groove of the recess.

  In the light guide sheet manufacturing method according to the present invention, the main body of the light guide sheet is made of polycarbonate resin.

  By irradiating a highly transparent polycarbonate coated with a halogen compound with laser light, multiple irregular shaped protrusions are formed in the groove of the recess. A light guide sheet that can increase the amount of light and improve the visibility of the illumination portion can be easily manufactured.

  In the light guide sheet manufacturing method according to the present invention, the halogen compound is NaCl.

  As a result, by forming a readily available and stable NaCl film on the light guide sheet made of polycarbonate and irradiating it with laser light, a plurality of irregular protrusion-shaped portions are formed in the grooves of the recesses. Therefore, it is possible to easily and safely manufacture a light guide sheet that can propagate light, increase the amount of light emitted from the illuminated portion, and improve the visibility of the illuminated portion.

As described above, in the present invention, since the protrusion-shaped portion is provided in the concave portion provided on the surface of the main body portion of the light guide sheet that propagates light, the light propagating through the light guide sheet is partly the protrusion-shaped portion of the concave portion. The light is emitted directly in multiple directions, and part of it is irregularly reflected by the projection-shaped part and diffuses light widely.Therefore, even when the concave part of the light guide sheet and the illuminated part are close by a thin illumination mechanism, It is possible to provide a light guide sheet that does not have insufficient light quantity.
Moreover, in the method for producing a light guide sheet according to the present invention, the film of the halogen compound is formed on the surface of the light guide sheet in advance. Since it can be created, it is not necessary to add a processing step for creating the projection-shaped portion, and the projection-shaped portion can be reliably manufactured without being shifted into the groove of the recess.

It is a perspective view which shows the external appearance of the light guide sheet which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the light guide sheet of the said embodiment. (A) is sectional drawing when a light guide sheet is cut | disconnected by AA of FIG. 1, (b) shows a normal structure when the light guide sheet of this embodiment is integrated in a portable terminal device etc. FIG. It is sectional drawing. It is a microscope picture of the processing sample which shows the state of the recessed part of the light guide sheet of this embodiment. It is a microscope picture which shows the state of the recessed part of the conventional light guide sheet which is not based on this invention. It is sectional drawing which shows typically the scattering state of the light in the light guide sheet of the said embodiment. These are sectional drawings which show typically the scattering state of the light in the conventional light guide sheet which is not based on this invention. It is a schematic diagram explaining the manufacturing method of the light guide sheet which concerns on embodiment of this invention. It is a schematic diagram explaining the manufacturing method of the conventional light guide sheet which is not based on this invention. It is sectional drawing which shows the structure of the conventional light guide sheet which is not based on this invention.

<Embodiment concerning light guide sheet>

  Hereinafter, the light guide sheet according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, the light guide sheet 1 according to the embodiment of the present invention is a plate-like component formed of a transparent resin such as polycarbonate, and a part of one side of the substantially rectangular main body 1a is formed. It protrudes in a trapezoidal shape, has a light incident portion 1e on the side surface of the protrusion, and a plurality of illumination portions 1d including a plurality of recesses 1b are provided on the surface of the main body portion 1a. In addition, since the light guide sheet 1 propagates light, by forming it with a polycarbonate resin having high transparency, it is possible to reduce light transmission loss and to increase the amount of light emitted from the illumination unit 1d. Can do.

  FIG. 2A shows an enlarged view from the light incident part 1e side to the vicinity of the illumination part 1d closest to the light incident part 1e when the light guide sheet 1 is cut along the AA section of FIG. It is sectional drawing.

  As shown to (a) of FIG. 2, the surface of the main-body part 1a of the light-guide sheet 1 is provided with the some recessed part 1b, and the illumination part 1d is comprised by the some recessed part 1b which adjoined, A plurality of protrusion-shaped portions 1c are provided on the recessed surface. The protrusion-shaped portion 1c may be a bubble having a hollow inside, or a solid lump filled with the same material as that of the main body 1a.

  When the light guide sheet 1 according to the embodiment of the present invention is incorporated into various electronic devices, normally, as shown in FIG. 2 (b), the key top 11 is laminated on the upper surface side of the light guide sheet 1, and the contact point on the lower surface side. The holding sheet 12 is laminated. Further, a spacer sheet 13 and a contact spring 14 are laminated on the lower surface of the contact holding sheet 12, and a substrate 21 for holding the light source 22 is laminated on the lower surface of the spacer sheet 13 and the contact spring 14, and provided on the upper surface of the substrate 21. The fixed contact 21a and the contact spring 14 are arranged to contact each other. At this time, the light guide sheet 1 and the key top 11 and the light guide sheet 1 and the contact holding sheet 12 are not completely adhered to each other, and an air layer is formed. However, the air layer is not necessarily formed. At this time, the light exit surface of the light source 22 is set to face the light incident portion 1 e of the light guide sheet 1. Also, the key top 11 usually has a plurality of illuminated portions 11a printed with numbers, symbols, etc., and the illuminated portion 11a of the key top 11, the illuminated portion 1d of the light guide sheet 1, and the contact spring 14 are provided. However, when the key top 11 is viewed from the upper surface, the key tops 11 are arranged at substantially the same position.

  As described above, when the light guide sheet 1 according to the embodiment of the present invention is incorporated in various electronic devices, the light emitted from the light source 22 enters the light guide sheet 1 from the light incident portion 1e, and the incident light is guided. The user can easily recognize the illuminated portion 11a of the key top 11 even in a dark place because the sheet 1 propagates and is emitted from the illuminated portion 1d to illuminate the illuminated portion 11a of the key top 11. Further, the illuminated portion 11a of the key top 11, the illuminated portion 1d of the light guide sheet 1, and the contact spring 14 are disposed so as to be in substantially the same position when the key top 11 is viewed from the top surface. Since the light sheet 1 and the contact holding sheet 12 have flexibility, when the user presses any one of the illuminated portions 11a of the key top 11, the light guide sheet below the depressed illuminated portion 11a. 1 and the contact holding sheet 12 bend and deform the contact spring 14 disposed below the pressed illuminated portion 11a, so that the contact spring 14 and the fixed contact 21b provided on the substrate 21 come into contact with each other, and the fixed contact 21a When the fixed contact 21b is turned on, it can be detected which illuminated portion 11a of the key top the user has pressed.

  Next, with reference to FIG. 3 and FIG. 4, the shape of the recessed part 1b in which the protrusion-shaped part 1c was provided in the hollow surface in the Example of this invention is demonstrated.

  The recess 1b shown in FIG. 3 is not a straight recess 1b shown in FIG. 1, but a micrograph showing a spot-like recess 1b sampled for explanation. FIG. 3 shows a dot-like recess 1b in which a protrusion-shaped portion 1c is provided on the recessed surface. FIG. 4 is a photomicrograph of a conventional concave portion 1f that is not according to the present invention and has no projection-shaped portion on the concave surface that is sample-processed for explanation.

  The conventional recessed part 1f of FIG. 4 which does not depend on the present invention and has no projection-shaped part on the recessed surface is a spherical recessed part on the surface of the light guide sheet 1, and the recessed surface is a smooth surface.

  On the other hand, the concave portion 1b shown in FIG. 3 in which the projection-shaped portion 1c is provided on the recessed surface in the embodiment of the present invention has an irregular-shaped projection-shaped portion 1c on the upper end side of the concave portion 1b. The amount of light emitted from the recess 1b is increased by the irregular projection-shaped portion 1c.

  Below, the light emission behavior of the light guide sheet 1 will be described with reference to FIGS. 5 and 6.

  FIG. 5 is an explanatory diagram illustrating a behavior in which light propagating through the light guide sheet 1 in the embodiment of the present invention is reflected by the concave portion 1b and emitted, and is a cross-sectional view of the light guide sheet 1 taken along the line BB in FIG. 4 is a cross-sectional view illustrating a state in which a key top 11 is stacked on the upper surface of the light guide sheet 1 and a contact holding sheet 12 is stacked on the lower surface of the light guide sheet 1 for convenience of the following description.

  In the cross-sectional shape of the light guide sheet 1 shown in FIG. 5, the light guide sheet 1 has a concave portion 1 b on the surface, and a protrusion-shaped portion 1 c on one upper end side of the concave portion 1 b. In addition, the cross-sectional shape of FIG. 5 is created based on the height measurement value in the BB cross-section line of the recessed part 1b shown in FIG. 3, and substantially reflects the actual shape of a sample processed product. If it demonstrates more concretely, the cross-sectional shape of the protrusion-shaped part 1c will be a shape close | similar to an ellipse in the shape which combined the upward convex shape and the downward convex shape. In addition, the case where the irregular-shaped protrusion-shaped part 1c is hollow with air bubbles is shown. Moreover, the case where an air layer exists between the contact holding sheet 12 and the light guide sheet 1 and between the key top 11 and the light guide sheet 1 is shown.

  FIG. 6 is an explanatory diagram illustrating the behavior of light propagating through the light guide sheet 31 that does not have a protrusion-shaped portion in the concave portion and is reflected by the concave portion 1f and is emitted from the concave portion according to the present invention. Therefore, a cross-sectional view in which the key top 11 is laminated on the upper surface of the light guide sheet 31 and the contact holding sheet 12 is laminated on the lower surface of the light guide sheet 31 is described.

  For convenience of explanation, first, with reference to FIG. 6, the light output behavior of a conventional light guide sheet 31 having no protrusion-shaped portion in the recess 1 f not according to the present invention will be described.

  In the conventional light guide sheet 31 having no projection-shaped portion on the recessed surface of the recess 1 f, the light LL propagated through the light guide sheet 31 is reflected by the recessed surface of the recess 1 f and proceeds to the lower surface side of the light guide sheet 31. Then, the light is reflected again by the lower surface of the contact holding sheet 12 or the light guide sheet 31 and proceeds to the upper surface side of the light guide sheet 31. Then, the light exits from the upper surface of the light guide sheet 31. The part 11a is illuminated.

  At this time, since the curvature of the recess surface of the recess 1f is large, the traveling direction of the light LL reflected by the recess surface of the recess 1f is closer to the direction in which the light LL has propagated than the direction orthogonal to the direction in which the light LL has propagated. Thus, the light LL reflected by the contact holding sheet 12 is emitted from a region away from the recess 1f. The traveling direction of the light LL reflected by the recessed surface of the recess 1f is reflected by the recessed surface of the recess 1f because the angle of the traveling direction gradually changes as the incident position on the recessed surface of the recess 1f gradually changes. The light LL is emitted in a shape reflecting the shape of the recess 1f in a wide range of the region away from the recess 1f.

  As described above, in the conventional light guide sheet 31 having no projection-shaped portion on the concave surface of the concave portion 1f, only the light reflected by the concave surface of the concave portion 1f is emitted from the illumination portion 31d and reflects the shape of the concave portion 1f. Therefore, when used in a portable terminal device such as a cellular phone in which the key top 11 is laminated directly on the light guide sheet 31, the illuminated portion 11a is entirely illuminated with the unevenness reflecting the shape of the recess 1f. Cannot be illuminated.

  Next, with reference to FIG. 5, the light emission behavior of the light guide sheet 1 in which the protruding portion 1c is provided on the recessed surface of the recess 1b according to the embodiment of the present invention will be described.

  In the light guide sheet 1 in which the protruding portion 1c is provided on the recessed surface of the recess 1b, a part of the light L1 propagating through the light guide sheet 1 is provided in the recess 1b as shown in FIG. A certain amount of light L1 travels from the hollow outer shape portion of the reached projection-shaped portion 1c to the projection-shaped portion 1c, and finally emits light from the projection-shaped portion 1c, and the key top 11 When illuminated, the illuminated portion 11a is illuminated while being diffused.

  In the light guide sheet 1 according to the embodiment of the present invention, since the protrusion-shaped portion 1c is provided on the upper end side of the recess 1b, the protrusion-shaped portion 1c and the illuminated portion 11a are close to each other. A part of the light L1 emitted directly from 1c can effectively illuminate the illuminated portion 11a.

  In addition, a part of the light L2 that has propagated through the light guide sheet 1 reaches the indeterminate protrusion-shaped part 1c provided in the recess 1b, and a part of the light L2 reaches the protrusion-shaped part 1c that has reached. The light is reflected by the hollow outer shape and proceeds to the lower surface side of the light guide sheet 1, but is reflected by the contact holding sheet 12 or the lower surface of the light guide sheet 1 and proceeds again to the upper surface side of the light guide sheet 1. When the light is emitted from the upper surface side and enters the key top 11, the key top 11 is illuminated while being diffused. At this time, since the curvature of the outer shape of the hollow protrusion-shaped portion 1c is small, the traveling direction of a part of the light L2 reflected by the hollow-shaped outer portion of the protrusion-shaped portion 1c is perpendicular to the direction in which the light has propagated. A part of the light L2 reflected by the contact holding sheet 12 is emitted from the periphery of the recess 1b. Further, since the protrusion-shaped portion 1c is indefinite, a part of the light L2 is reflected in an unspecified direction by the hollow outer shape portion of the protrusion-shaped portion 1c, and thus reflected by the hollow outer shape portion of the protrusion-shaped portion 1c. Then, a part of the light L2 reflected again by the lower surface of the contact holding sheet 12 or the light guide sheet 1 is emitted in an irregular shape from the periphery of the recess 1b, and illuminates the illuminated portion 11a as a whole. In addition, the one part light L2 shown in FIG. 5 has shown the case where it reflects on the lower surface of the light guide sheet 1. FIG.

  In the light guide sheet 1 according to the embodiment of the present invention, since the plurality of protrusion-shaped portions 1c are provided in the recess 1b, a part of the light L1 directly emitted from the plurality of protrusion-shaped portions 1c and the plurality of protrusion-shaped portions 1c. A part of the light L2 that is emitted after being reflected by the light becomes plural, and the amount of light emitted from the light guide sheet 1 can be improved.

  In addition, a part of the light L3 propagating through the light guide sheet 1 is reflected by the recessed surface of the recess 1b and travels to the lower surface side of the light guide sheet 1, but the contact holding sheet 12 or the light guide sheet 1 The light is reflected by the lower surface and travels again to the upper surface side of the light guide sheet 1. Then, the light is emitted from the upper surface side of the light guide sheet 1, and when it enters the key top 11, the key top 11 is illuminated while being diffused. At this time, since the curvature of the concave surface of the concave portion 1b is large, the traveling direction of a part of the light L3 reflected by the concave surface of the concave portion 1b propagates the light L3 from the direction orthogonal to the direction in which the light L3 propagates. A part of the light L3 reflected in the direction and reflected by the contact holding sheet 12 is emitted from a region away from the recess 1b. Further, the traveling direction of a part of the light L3 reflected by the concave surface of the concave portion 1b is reflected by the concave surface of the concave portion 1b because the angle of the traveling direction gradually changes when the incident position on the concave surface of the concave portion 1b changes. The part of the light L3 thus emitted is emitted in a shape reflecting the shape of the concave portion 1b from a range where the region away from the concave portion 1b is expanded.

  A part of the light L3 reflected by the concave surface of the concave portion 1b is emitted in a shape reflecting the shape of the concave portion 1b, but proceeds from the hollow outer shape portion of the protruding shape portion 1c to the inside of the protruding shape portion 1c, and the protruding shape portion 1c. To overlap with a part of the light L1 emitted from the light and a part of the light L2 reflected from the hollow outer shape part of the protrusion-shaped part 1c and reflected again by the contact holding sheet 12 and emitted from the upper surface side of the light guide sheet 1. The illuminated portion 11a is illuminated more brightly.

As described above, in the light guide sheet 1 according to the embodiment of the present invention, the light propagating through the light guide sheet 1 is reflected by the recessed surfaces of the plurality of recesses 1b provided on the surface of the light guide sheet and emitted. Since the light passing through the projection-shaped portion 1c provided in the recess 1b or reflected by the projection-shaped portion 1c is also emitted, the illumination portion 1d can be illuminated more brightly.
Furthermore, since the light reflected by the protrusion-shaped portion 1c is emitted indefinitely from the periphery of the recess 1b and illuminates the entire illumination portion 1d, the recess 1b of the light guide sheet 1 and the illuminated portion 11a approach each other. Even if it exists, the to-be-illuminated part 11a can be illuminated uniformly.

  In the above embodiment, the protrusion-shaped portion 1c is a bubble. However, even when the protrusion-shaped portion 1c is solid, the same light-emitting behavior is obtained only by changing the light-emitting angle. Moreover, although the light emission behavior when the contact holding sheet 12 is laminated on the light guide sheet 1 is described, even if a white or other reflective sheet is arranged on the upper surface side of the contact holding sheet 12, the same light emission behavior can be obtained. . Moreover, since the light that has entered the key top 11 is emitted from the upper surface side as diffused light, the illuminated portion 11a can be illuminated more brightly.

  Moreover, although the shape of the plurality of recesses 1b is linear, the plurality of recesses may be a set of a large number of points, and the same light output behavior can be obtained even in a composite shape such as a straight line such as a stitch shape.

  In the embodiment of the present invention, the case where the plurality of concave portions 1b provided with the protrusion-shaped portions 1c is provided on the upper surface of the light guide sheet 1 is shown. Or may be provided on both the upper and lower surfaces of the light guide sheet 1.

<Embodiment concerning manufacturing method of light guide sheet>

  Next, with reference to FIG. 7 and FIG. 8, the manufacturing method of the light guide sheet which concerns on embodiment of this invention is demonstrated.

  FIG. 7 is a schematic diagram illustrating a method for manufacturing a light guide sheet according to an embodiment of the present invention. FIG. 8 is a schematic view for explaining a conventional method of manufacturing a light guide sheet not according to the present invention.

  For convenience of explanation, first, referring to FIG. 8, a conventional method of manufacturing the light guide sheet 31 in which there is no protruding portion on the recessed surface of the recess 1 f not according to the present invention will be described. 8A shows the light guide sheet 31 before the recess processing, FIG. 8B shows the process of processing the light guide sheet 31 with the laser beam 51, and FIG. 8C shows the guide. A state in which the recess 1 f is processed in the optical sheet 31 is shown.

  In the conventional light guide sheet 31 disclosed in Patent Document 1, the surface of the light guide sheet 31 shown in FIG. 8A is irradiated with laser light 51 as shown in FIG. 8B. The material of the light guide sheet 31 is sublimated and scattered, and a recess 1 f is processed on the surface of the light guide sheet 31 as shown in FIG. At this time, the energy of the laser beam 51 is given to the surface of the light guide sheet 31, and the recessed portion of the formed recess 1 f becomes a smooth mirror surface throughout the entire area, so that light propagating inside the light guide sheet 31 is guided. When it hits the inner surface of the recess portion 1f from the inside of the sheet 31, the light is not irregularly reflected on the inner surface, and is reflected in the light guide sheet 31 according to the incident angle and the reflection angle principle according to the angle of the inner surface. .

  Next, with reference to FIG. 7, the manufacturing method of the light guide sheet 1 which has the protrusion-shaped part 1c in the hollow surface of the recessed part 1b which concerns on embodiment of this invention is described.

  FIG. 7A shows the light guide sheet 1 before processing. In the embodiment of the present invention, the light guide sheet 1 is made of polycarbonate resin.

  Next, as shown in FIG. 7 (b), the halogen compound solution 2 is applied to the surface of the light guide sheet 1 on the side where the recesses are provided, and then the halogen compound solution 2 is dried. As shown in FIG. 3, the halogen compound film 3 is formed on the surface of the light guide sheet 1. In this embodiment, NaCl, which is easily available and stable, is used as the halogen compound.

  Next, as shown in FIG. 7D, the surface of the light guide sheet 31 on which the halogen compound film 3 is formed is irradiated with laser light 51. At this time, depending on the shape of the recess 1b to be processed, for example, when processing a spot-like recess, only one point is irradiated with the laser beam 51, and when processing a linear recess or a mesh-like recess, the laser beam is used. The laser beam 51 is continuously irradiated while relatively moving the 51 and the light guide sheet 1.

  When the material of the light guide sheet 31 is sublimated and scattered by the irradiation of the laser beam 51, the concave portion 1b is processed on the surface of the light guide sheet 1 as shown in FIG. The fixed protrusion-shaped part 1c is processed. After that, the processed halogen compound film 3 formed on the surface of the light guide sheet 1 is removed by washing or the like, so that the concave portion 1b and the irregular projection-shaped portion 1c shown in FIG. The light guide sheet 1 is obtained. Further, when the halogen compound film 3 is sufficiently diluted and has no optical influence, it is not necessary to remove it.

  The manufacturing method of the light guide sheet according to the embodiment of the present invention is as described above. By irradiating the surface of the light guide sheet 31 on which the halogen compound film 3 is formed with the laser beam 51, the concave portion 1b and the irregular shape are formed. The reason why the protrusion-shaped portions 1c are simultaneously formed is estimated as follows.

  In the laser processing shown in FIG. 7D, the concave portion 1b is formed by the sublimation and scattering of the polycarbonate resin, which is the material of the light guide sheet 1, from the solid to the gas due to the heat of the laser beam 51. By the way, generally halogen compounds are known as substances exhibiting flame retardancy. For example, when NaCl is used as a halogen compound, chlorine contained in NaCl is a factor that inhibits sublimation of polycarbonate resin during laser processing. It is thought that it becomes.

Therefore, when the light guide sheet 1 is heated by the laser beam 51, the polycarbonate resin on the surface of the light guide sheet 1 that is in contact with the halogen compound film 3 is inhibited from sublimation and becomes a liquid. The deeper part of the polycarbonate resin sublimates to become a gas and scatters.
However, since the polycarbonate resin on the surface of the light guide sheet 1 does not scatter and remains as a liquid, the polycarbonate resin deeper than the surface of the light guide sheet 1 that has been sublimated into gas remains as a liquid without scattering. It is presumed that the polycarbonate resin on the surface is inhibited from scattering and becomes air bubbles, which are cooled and solidified to form the irregular projection-shaped portion 1c.

  In addition, since the pressure of the gaseous polycarbonate resin that is sublimated and scattered is strong in the central part of the width of the concave portion 1b, it is difficult to generate bubbles because it is scattered through the liquid polycarbonate resin on the surface, but the width of the concave portion 1b At the edge portion, the pressure of the gaseous polycarbonate resin to be scattered is weak, and the liquid polycarbonate resin in the central portion of the width of the recess 1b gathers at the edge of the width of the recess 1b to increase the thickness. For this reason, it is presumed that the deep polycarbonate resin that has been sublimated into gas is difficult to penetrate through the liquid polycarbonate resin on the surface and easily form bubbles.

  The above is the formation process of the bubble-shaped protrusion 1c inferred from the behavior of the polycarbonate resin during laser processing and the characteristics of the halogen processed material. When the processed recess 1b is observed in detail, the irregular protrusion-shaped portion Although it is unclear in 1c, since a Newton ring-like pattern is seen, it is considered that the protrusion-shaped part is a thin film, and the protrusion-shaped part 1c formed by the light guide sheet manufacturing method according to the embodiment of the present invention. Can be assumed to be bubbles.

  In the light guide sheet manufacturing method according to the present invention, the main body 1a of the light guide sheet 1 is made of polycarbonate resin. As a result, a plurality of irregular projection-shaped portions 1c are formed in the grooves of the recesses 1b by irradiating a highly transparent polycarbonate coated with a halogen compound in the grooves of the recesses 1b. It is possible to easily manufacture the light guide sheet 1 that can increase the amount of light emitted from the light source and improve the visibility of the illuminated portion.

  Furthermore, in the light guide sheet 1 made of polycarbonate resin, it has been confirmed by experiments and the like that the method of manufacturing the light guide sheet according to the present invention can create the irregular protrusion-shaped part 1c in the concave part 1b simultaneously with the processing of the concave part 1b by laser light. Thus, the protrusion-shaped portion 1c can be easily and reliably formed on the recessed surface of the recess 1b.

As described above, in the method for manufacturing a light guide sheet according to the present invention, NaCl, which is an easily available and stable halogen compound, is applied to the surface of the main body of the light guide sheet, and a recess is formed on the surface by irradiating laser light. In addition, it is possible to form an indeterminate protrusion-shaped portion in the recess.
As a result, it is possible to create a concave portion and an irregularly shaped projection shape portion of the concave portion at the same time simply by forming a film of a halogen compound in advance on the surface of the light guide sheet, so an additional process is added to create the projection shape portion. There is no need, and furthermore, the protrusion-shaped part can be reliably formed without being shifted into the groove of the recess.

  The halogen compound to be applied is not limited to NaCl, and various compounds of halogen group elements such as fluorine, chlorine, bromine and iodine can be used.

DESCRIPTION OF SYMBOLS 1 Light guide sheet 1a Main body part 1b Recessed part 1c Projection-shaped part 1d Illuminated part 1e Light incident part 1f Recessed part 2 Halogen compound solution 3 Halogen compound film 11 Key top 11a Illuminated part 12 Contact holding sheet 13 Spacer sheet 21 Substrate 21a Fixed contact 21b Fixed contact 22 Light source 31 Light guide sheet 31d Illuminating part 51 Laser light 102 Chassis 120 Membrane laminate 121 Substrate sheet 122 Press sheet 122a Back surface 123 Spacer layer 123a Organic resin layer 123b Adhesive layer 124 Key top 125 Lower contact 126 Upper contact 127 Reflection area 128 Recess 129 Light-emitting diode device L1 light L2 light L3 light LL light

Claims (8)

  A main body that propagates light from an external light source, and a plurality of recesses are provided on at least one surface of the main body, and the propagated light is reflected by the plurality of recesses to emit light from the main body. In the light guide sheet, at least one of the plurality of recesses is provided with a protrusion-shaped portion.   The light guide sheet according to claim 1, wherein the protrusion-shaped portion is provided on an upper end side of the concave portion.   The light guide sheet according to claim 1, wherein a plurality of the protrusion-shaped portions are provided in the recess.   The light guide sheet according to any one of claims 1 to 3, wherein the plurality of protrusion-shaped portions are indefinite.   The light guide sheet according to claim 1, wherein the main body portion is mainly made of a polycarbonate resin.   A light guide sheet manufactured by applying a halogen compound to a surface of a main body and irradiating a laser beam to form a recess in the surface and to form an irregular protrusion-shaped portion in the recess. Method.   The method of manufacturing a light guide sheet according to claim 6, wherein the main body portion is made of polycarbonate resin. The method for manufacturing a light guide sheet according to claim 6, wherein the halogen compound is NaCl.