JP2008234863A - Illuminating sheet structure and operation switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminating sheet structure making it hard to attenuate light to be guided irrespective of the property of a surface on which the illuminating sheet is arranged, and making it easy to emit high-intensity light at a predetermined emitting area. <P>SOLUTION: The illuminating sheet structure is provided with an illuminating sheet 10 formed on one surface thereof a predetermined emitting area 15 from which light led from a light source 13 through an sheet-like interior portion of the illuminating sheet is emitted, and a substrate 11 on which the illuminating sheet is disposed with the other surface thereof contacting with the substrate. The illuminating sheet 10 has a sheet-like core layer 21 to which the light is led, and the surface of the core layer at the side of the substrate 11 is coated with a clad layer 23 which is lower in refractive index than the core layer 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an illumination sheet structure including an illumination sheet that guides light from a light source and emits light from a predetermined radiation surface area, and an operation switch using the illumination sheet structure.

  2. Description of the Related Art In recent years, illumination sheets configured to guide light from a light source through a sheet-shaped interior and emit the light in a predetermined radiation surface area on the surface have been proposed in various fields.

  For example, Patent Document 1 below proposes a keypad provided with at least one reflection pattern for reflecting a part of light spreading in the light guide plate to the surface side. Here, since the reflection pattern is locally provided, light can be emitted from a part of the surface. In Patent Document 1, light traveling inside the light guide plate is totally reflected at the boundary with the external air layer, so that it is difficult for light to be radiated to the outside at portions other than the reflection pattern.

In order to construct a keypad assembly using this keypad, a light guide plate is laminated on a switch board having a dome portion, a reflection pattern is disposed on the dome portion, and a key button is positioned at a position facing the dome portion. Place. In this keypad device, the light guided by the light guide plate is diffusely reflected by the reflection pattern and emitted, so that the key button can be illuminated from the back side.
JP 2006-323843 A

  However, in such a conventional structure such as a keypad assembly, a light guiding layer such as a light guide plate is disposed in direct contact with an arrangement surface such as a substrate or a dome. Therefore, when there are unevenness or rough surfaces such as steps, protrusions, etc. on the arrangement surface, or when adhesive etc. are attached, irregular reflection or absorption of light guided at that part occurs, and light is emitted. It was easy to be attenuated, and the light emitted from the predetermined radiation surface area was easily weakened.

  Accordingly, an object of the present invention is to provide an illuminating sheet structure in which the guided light is not easily attenuated regardless of the nature of the arrangement surface of the illuminating sheet, and strong light can be easily emitted in a predetermined radiation surface area. Another object is to provide an operation switch using such an illumination sheet structure.

  The illumination sheet structure according to claim 1, wherein the light from the light source is guided through the inside of the sheet shape and is emitted from a predetermined radiation surface area provided on one surface, and the illumination sheet An illumination sheet structure including a substrate disposed in contact with the other surface, the illumination sheet includes a sheet-like core layer through which the light is guided, and a surface of the core layer on the substrate side And a clad layer having a refractive index lower than that of the core layer.

  The illumination sheet structure according to a second aspect is characterized in that, in addition to the configuration according to the first aspect, a surface of the core layer opposite to the base side is covered with the clad layer.

  The illumination sheet structure according to claim 3 is characterized in that, in addition to the configuration according to claim 1 or 2, the surface of the core layer covered by the clad layer is a mirror surface.

  In addition to the structure according to any one of claims 1 to 3, the illumination sheet structure according to claim 4 irregularly reflects light guided in the core layer to the core layer in the radiation surface region. An irregular reflection part is provided for the purpose.

  In addition to the structure according to any one of claims 1 to 4, the illumination sheet structure according to claim 5 is arranged so that the illumination sheet is in contact with the core layer in the radiation surface region. The interface with the clad layer has an uneven shape corresponding to the uneven portion.

  In addition to the structure according to any one of Claims 1 to 5, the illumination sheet structure according to Claim 6 has a surface shape changing portion on which the substrate is disposed in contact with the illumination sheet. And the thickness of the clad layer is thicker than the surface shape change portion, and changes substantially corresponding to the shape of the surface shape change portion, so that the gap between the clad layer and the core layer is The interface is formed flatter than the surface shape of the surface shape changing portion.

  The operation switch according to claim 7 is a surface operation unit that is pressed from the surface side, and the illumination sheet structure according to any one of claims 1 to 6 that is disposed to face the surface operation unit. A light source that supplies light to the illumination sheet, and the surface operation unit transmits light from the radiation surface region to a position corresponding to the radiation surface region of the illumination sheet. And a transparent display portion configured to be visually recognized from the surface side, and the base portion has an elastic shape having a hollow three-dimensional shape that can be elastically deformed at a position corresponding to the radiation surface region of the illumination sheet. A dome is provided so that the illumination sheet is disposed along the surface of the base portion, and the pressing operation is performed on the surface operation unit, whereby the elastic dome is interposed through the radiation surface region of the illumination sheet. Is pressed and elastic Characterized in that it is configured to form.

  According to the illumination sheet structure of the first aspect, since the surface of the core layer on which the light of the illumination sheet is guided is covered with the cladding layer, the core layer is disposed on the surface of the substrate or on the substrate. There is no direct contact with various members. Further, since the cladding layer has a lower refractive index than the core layer, the light traveling in the core layer is guided while being reflected at the interface with the cladding layer. For this reason, even if there is a portion where light is diffusely reflected or absorbed easily on the arrangement surface of the substrate or a member disposed on the substrate, the light traveling in the core layer is not easily attenuated by the irregular reflection or absorption. As a result, it is possible to provide an illumination sheet structure that easily emits strong light in a predetermined radiation surface area regardless of the nature of the arrangement surface of the substrate.

  According to the illumination sheet structure of the second aspect, since the surface of the core layer opposite to the substrate side is also covered with the cladding layer, the surface of the core layer is damaged or dust or the like adheres. It is possible to prevent the light from being attenuated by irregular reflection or absorption on the surface of the core layer opposite to the base.

  According to the illumination sheet structure of the third aspect, since the surface of the core layer covered by the cladding layer is a mirror surface, the light traveling in the core layer is more easily reflected at the interface with the cladding layer, and the light is transmitted. It can be made more difficult to attenuate.

  According to the invention described in claim 4, since the irregular reflection part for irregularly reflecting light is provided in the core layer of the radiation surface region, the light guided in the core layer is reliably emitted from the radiation surface region. Easy to do.

  According to the illumination sheet structure according to claim 5, the arrangement surface of the substrate on which the illumination sheet is placed in contact has a flat portion and an uneven portion, the radiation surface region is disposed in the uneven portion, and the radiation surface region Since the interface between the core layer and the clad layer has a concavo-convex shape corresponding to the concavo-convex portion, the incident angle with respect to the interface with the clad layer reflecting the inside of the core layer in the radiation surface region is set to a flat portion. It can be made different from the part arranged in. Therefore, light can be easily emitted from the core layer, and light emitted from the radiation surface area can be easily strengthened.

  According to the illumination sheet structure according to claim 6, the surface of the substrate is provided with the surface shape changing portion, the thickness of the cladding layer is formed to be thicker than the surface shape changing portion, and the thickness is the surface shape. By changing substantially corresponding to the shape of the changed portion, the interface between the cladding layer and the core layer is formed to be flatter than the surface shape of the surface shape changed portion. The incident angle with respect to the interface with the cladding layer hardly changes greatly at a position corresponding to the surface shape change portion. Therefore, it is easy to prevent light from being emitted from the core layer at a position corresponding to the surface shape changing portion, and it is easy to prevent attenuation of the guided light.

  According to the operation switch of the seventh aspect, since the illumination sheet structure is the one described in any one of the first to sixth aspects, the region other than the radiation surface region is used regardless of the nature of the arrangement surface of the base body. It is easy to emit strong light in the radiation surface area by suppressing attenuation of light in the area. In addition, since the elastic dome projects from the base portion and the radiation surface area of the illumination sheet is arranged along the elastic dome, light can be easily emitted from the core layer in the radiation surface area, and the emitted light can be Easy to be stronger. Therefore, light from the light source can be efficiently emitted from the translucent display unit, and an efficient operation switch can be provided by suppressing the number of light sources and the amount of light.

[Embodiment 1]

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 3 show an illumination sheet structure according to the first embodiment. This illuminating sheet structure is used for backlights of various types of display bodies, and is disposed on the back side of a display unit (not shown) to irradiate a predetermined position from the back side and transmit light transmitted to the front side. It is used so as to be visually recognized.

  In this Embodiment 1, as shown in FIG.1 and FIG.2, the other surface of the illumination sheet 10 which can radiate | emit the light from the radiation | emission surface area | region 15 provided in the predetermined position of one surface, and the illumination sheet 10 is shown. And a support base 11 arranged in contact with the light source 13 such as an LED provided on the support base 11 to supply light to the illumination sheet 10 in the surface direction, thereby providing radiation provided at a plurality of positions. It is used to emit light from the surface region 15.

  As shown in FIG. 3, the illumination sheet 10 includes a sheet-like core layer 21 for guiding light inside, and clad layers 22 and 23 covering both surfaces of the core layer 21, and the core layer 21. And the cladding layers 22 and 23 are in close contact with each other and are integrally joined. The illumination sheet 10 has flexibility that can be arranged along the arrangement surface 11 a of the support base 11, and the entire surface of the clad layer 23 is disposed on the support base 11 side of the core layer 21. It is in close contact with.

  In the radiating surface region 15, a rough surface 21 a made of fine irregularities is formed on the surface of the core layer 21 on the cladding layer 22 side, whereby an irregular reflection portion 25 for irregularly reflecting light guided in the core layer 21. Is provided.

  A light source arrangement hole 29 is provided at an arrangement position of the light source 13 different from the radiation surface region 15, and the light source 13 such as an LED is accommodated therein. A light shielding layer 27 that shields light from the light source 13 is provided on the surface of the cladding layer 22 around the position where the light source 13 is disposed.

  The core layer 21 of the illumination sheet 10 is a layer that has transparency and guides light by transmitting light in the surface direction. The core layer 21 is preferably a layer having a light transmittance of 80% or more in the visible light region. This is because the higher the transmittance is, the more the attenuation of the guided light can be suppressed.

  The refractive index of the core layer 21 is preferably as high as possible, for example, 1.3 or more. This is because the range of materials that can be used as the clad layers 22 and 23 described later can be widened.

  As a material constituting the core layer 21, for example, a resin such as silicone, polyurethane, or polycarbonate, an elastomer, or the like can be used.

  The thickness of the core layer 21 can be appropriately selected according to the use of the core layer 21 and the like, but it is preferable that the core layer 21 be formed as thin as possible within a range in which desired luminance can be secured in the radiation surface region 15. However, the area of the incident surface on which the light from the light source 13 is incident facing the light source 13 needs to be at least 50% or more of the area of the light emitting surface on the opposite side of the light source 13.

  It is preferable that the surface of the core layer 21 on the side of the clad layer 23 that is the support base 11 side is formed in a mirror surface over the entire surface, and the surface on the side of the clad layer 22 is also formed in a mirror surface except for the radiation surface region 15. Is preferred. If it is a mirror surface, the light guided in the core layer 21 is diffusely reflected at the interface between the core layer 21 and the cladding layers 22 and 23 and is emitted from the core layer 21 in a region other than the radiation surface region 15. This is because the light guiding performance can be easily improved.

  This mirror surface is a state in which the surface roughness is kept small. For example, when the mirror surface is molded using a mold, the mirror surface can be produced by suppressing the surface roughness of the mold surface to be small. As the surface roughness of the mold surface, for example, an arithmetic average roughness (Ra) measured by a three-dimensional shape measuring device or the like is preferably in the range of 0.01 to 0.5 μm.

  The rough surface 21 a formed on the surface of the core layer 21 on the cladding layer 22 side in the radiation surface region 15 is a range where the light guided in the core layer 21 is diffusely reflected and can be emitted from the surface of the core layer 21. For example, when the mirror surface of the core layer 21 is molded by a mold, the surface roughness of the mold surface is an arithmetic average roughness (Ra) measured by a three-dimensional shape measuring device or the like of 1.0 μm or more. If there is, it is preferable.

  On the other hand, the cladding layers 22 and 23 of the illuminating sheet 10 are layers for allowing the light traveling in the core layer 21 to be guided through the core layer 21 while being reflected at the interface with the core layer 21. is there.

  The cladding layers 22 and 23 are required to be at least smaller than the refractive index of the core layer 21, and are preferably smaller than the refractive index of the core layer 21 by 0.1% or more, and particularly smaller by 1% or more. Is preferred. This is because the condition for total reflection of light guided through the core layer 21 becomes narrower as the refractive index of the cladding layers 22 and 23 increases, and the light guide performance decreases.

  The cladding layers 22 and 23 may be less transparent than the core layer 21. This is because, since the surface of the core layer 21 is a mirror surface, the light guided in the core layer 21 can be sufficiently reflected at the interface with the cladding layers 22 and 23, and the influence on the reflection condition of the guided light is small.

  In the case of the cladding layer 22 having transparency, light leaking from the core layer 21 may be emitted as weak light from a part or the whole of the cladding layer 22. In that case, the design may be imparted by intentionally radiating the leaked light, and the leaked light is reflected on at least a part or all of the outer surface of the cladding layer 22 except the radiation surface region 15. For this purpose, a reflective coating such as a metal or a light shielding coating may be provided for shielding. When the reflective coating is provided, light leaked from the core layer 21 can be supplied to the core layer 21 again.

  The material constituting the cladding layers 22 and 23 is required to be a material that can be laminated and integrated with the core layer 21 without interposing other materials such as an adhesive. Specifically, fluororesins such as polytetrafluoroethylene, other resins, elastomers, and the like can be used. A material that can reduce the apparent refractive index by holding air in the porous space, such as silica, may be used.

  The thickness of the clad layer 22 on the display body side is preferably as thin as possible as long as a protective function capable of preventing damage such as scratches from the outside can be secured on the mirror surface of the core layer 21. This is because the clad layer 22 is a layer used to reflect the light guided in the core layer 21 at the interface with the core layer 21, so that the influence of the thickness is small.

  On the other hand, the thickness of the clad layer 23 on the support base 11 side is a surface shape changing portion 11b formed on the placement surface 11a of the support base 11, for example, a rough surface, a protrusion formed intentionally or unavoidably on the placement surface 11a, Alternatively, it is preferable that the thickness of the step or the circuit or coating formed on the arrangement surface 11a is such that the change in height in the direction orthogonal to the surface of the support substrate 11 can be absorbed as much as possible. For example, you may form thicker than the surface shape change part 11b formed in the arrangement | positioning surface 11a of the support base 11. FIG. Specifically, when the support base 11 is a printed board, it may be formed thicker than the distance between the circuit surface to be disposed and the board surface.

  In that case, at least in a region other than the radiation surface region 15, the thickness of the cladding layer 23 changes substantially corresponding to the shape of the surface shape changing portion 11 b, whereby the interface between the cladding layer 23 and the core layer 21. However, it is preferable that the surface shape of the surface shape changing portion 11b is formed to be flatter. In this way, it is easy to prevent the incident angle of the light traveling while reflecting in the core layer 21 with respect to the interface with the cladding layer 23 from changing greatly at the position of the surface shape changing portion 11b. In this region, it is possible to make it difficult for light to be emitted from the core layer 21.

  In the first embodiment, the cladding layers 22 and 23 are preferably covered with the surface of the core layer 21 in close contact with each other over the entire surface. When the core layer 21 and the clad layers 22 and 23 are arranged adjacent to each other without being in close contact with each other, the portion where the air layer is partially interposed between the core layer 21 and the clad layer 22 are in close contact with each other. Part occurs. Then, since the refractive indexes of the cladding layers 22 and 23 and the air layer are different, the reflection conditions of the light guided in the core layer 21 are partially different, and as a result, the light radiated to the outside in the entire illumination sheet 10 This is because unevenness is likely to occur and light is likely to leak partially in a region other than the radiation surface region 15.

  In addition, when the illuminated display body is disposed apart from the cladding layer 22 on the display body side, the surface of the cladding layer 22 is preferably rougher than the surface of the core layer 21. This is because if it is formed on a mirror surface, dust and the like are likely to adhere. When the exposed surface of the clad layer 22 is formed using a mold, the surface roughness of the mold surface is, for example, an arithmetic average roughness (Ra) measured by a three-dimensional shape measuring device or the like. It is preferable that it is larger than 1.0 μm.

  On the other hand, the surface of the clad layer 23 on the support base 11 side only needs to be stably disposed on the placement surface 11a of the support base 11, and even if a gap is formed between the surface of the clad layer 23 and the placement surface 11a. Good. Further, an adhesive, an adhesive tape, or the like may be interposed between the surface of the clad layer 23 and the arrangement surface 11a.

  Next, the light shielding layer 27 of the illumination sheet 10 is a layer that prevents light from the light source 13 from being transmitted through the cladding layer 22 and directly emitted to the outside.

  The light shielding layer 27 is made of an opaque layer that can reliably shield light, and is preferably deformable together with the cladding layer 22. The light shielding layer 27 may be opaque and have a reflection effect. The light shielding layer 27 may be directly bonded to the cladding layer 22 by printing or the like, but may be bonded via another layer such as an adhesive or a double-sided pressure-sensitive adhesive tape. This is because there is no influence on the light guided in the core layer 21 because it does not directly contact the core layer 21.

  As such a light shielding layer 27, for example, a resin such as silicone, polyurethane, or polycarbonate, an elastomer, a metal such as stainless steel, or aluminum can be used. As described above, when a light-shielding film or a reflective film is provided in order to prevent the clad layer 22 from emitting light as weak light, the film may be used as the light-shielding layer 27. The thickness of the light shielding layer 27 is preferably as thin as possible within a range where sufficient light shielding properties can be obtained.

  The light shielding layer 27 is disposed immediately above and around the light source 13 and is required not to exist in the radiation surface region 15. The light-shielding layer 27 is disposed until the incident angle at which light supplied from the light source 13 to the core layer 21 reaches an interface between the core layer 21 and the cladding layer 22 so that the light can be substantially totally reflected. It is preferable to arrange so as to cover the range.

  In order to manufacture the illuminating sheet 10 having such a configuration, for example, a core layer forming sheet material capable of forming the core layer 21 in advance is provided with a rough surface 21a at a predetermined position on the surface and the remaining portion becomes a mirror surface. It can be manufactured by applying and curing a paste or the like that can form the cladding layers 22 and 23 on the surface of the mirror surface for forming the core layer.

  In addition, a pair of clad layer forming sheets in which a rough surface is formed at a predetermined position on the surface facing the core layer 21 and the remaining part is formed as a mirror surface can be prepared in advance, and the core layer 21 can be formed between the clad layer forming sheets. You may manufacture by apply | coating a paste etc. and making it harden | cure.

  In such an illuminating sheet 10, light can be emitted from the radiation surface region 15 on the surface by causing the light source 13 to emit light while being arranged on the support base 11.

  Here, first, when the light source 13 emits light, the light is radiated from the point light source in all directions in the light source arrangement hole 29 of the core layer 21, supplied to the core layer 21 and the cladding layers 22 and 23, and incident. Light incident in a direction that substantially intersects the surface direction of the core layer 21 passes through the core layer 21 and the cladding layers 22 and 23, reaches the light shielding layer 27, and is shielded. Light incident along the surface direction of the core layer 21 is guided through the inside of the sheet-like core layer 21 while being reflected by the cladding layers 22 and 23. And the light which reached the irregular reflection part 25 of the core layer 21 among the light is radiated | emitted from the radiation | emission surface area | region 15 through the cladding layer 22 outside by being irregularly reflected by a rough surface. The remaining light is further guided through the core layer 21 and is radiated to the outside from the other irregular reflection portions 25 in the same manner.

  According to the illuminating sheet structure as described above, the surface of the core layer 21 to which the light of the illuminating sheet 10 is guided is covered with the cladding layer 23, so the core layer 21 is the surface of the supporting substrate 11. In addition, various members arranged on the support base 11 are not in direct contact. Further, since the cladding layer 23 has a lower refractive index than the core layer 21, the light traveling in the core layer 21 can be guided while being reflected at the interface with the cladding layer 23. For this reason, the surface 11a of the surface of the support base 11 and various members arranged on the support base 11 includes a surface shape changing portion 11b where light such as rough surfaces and unevenness is likely to be irregularly reflected and a portion where light is easily absorbed. Even in such a case, the light traveling through the core layer 21 is difficult to be diffusely reflected or absorbed, and the guided light is difficult to attenuate. As a result, regardless of the surface properties of the arrangement surface 11a, strong light can be emitted from the predetermined radiation surface region 15.

  Further, according to the illumination sheet structure, the surface of the core layer 21 on the display body side opposite to the support base 11 side is covered with the clad layer 22, so that the surface of the core layer 21 is damaged, Dust and the like can be prevented from adhering, and it is easy to prevent the light guide performance from being deteriorated due to irregular reflection on the surface of the core layer 21 on the display body side.

  Moreover, since the surface of the core layer 21 covered by the cladding layers 22 and 23 is a mirror surface, the light traveling through the core layer 21 is more easily reflected at the interface with the cladding layers 22 and 23, and the light is less likely to be attenuated. it can.

  Further, since the irregular reflection portion 25 for irregularly reflecting light is provided in the core layer 21 of the radiation surface region 15, the light guided in the core layer 21 can be reliably emitted from the radiation surface region 15. It is.

  The first embodiment can be appropriately changed within the scope of the present invention. For example, in the first embodiment, the example in which the cladding layer 22 is provided on the surface of the core layer 21 on the display body side, which is the irradiation side, has been described. However, the cladding layer 22 is provided on the display body side of the core layer 21. Instead, the surface of the core layer 21 may be exposed. In this case, the surface of the core layer 21 comes into contact with the air layer, and light traveling through the core layer 21 can be guided while being reflected at the interface with the air layer.

In the above description, the irregular reflection portion 25 is constituted by the rough surface 21a formed on the surface of the core layer 21 on the clad layer 22 side. However, the irregular reflection portion 25 is not particularly limited as long as the light guided in the core layer 21 is irregularly reflected. Is not to be done. For example, it may be a rough surface formed on the surface on the core layer 21 side, and is configured by including a light-dispersing material such as a filler or fine particles in the core layer 21 or through holes provided in the core layer 21. Is also possible. Further, a phosphorescent material or a phosphorescent material can be contained in the core layer 21 of the radiation surface region 15.
[Embodiment 2]

  4 and 5 show the second embodiment.

  The second embodiment is an example in which the illumination sheet structure of the first embodiment is used for a mobile phone as an operation switch.

  As shown in FIGS. 4 and 5, the mobile phone includes a housing 30 having an opening 30a, an operation panel 31 serving as an operation switch cover member disposed in the opening 30a of the housing 30, and a housing. 30 is provided with a base portion 32 disposed opposite to the operation panel 31 and an illumination sheet 10 disposed on the base portion 32, and an illumination sheet structure including the illumination sheet 10 and the base portion 32. The operation panel 31 can be irradiated from the back side.

  The operation panel 31 is provided with a plurality of pressing operation portions 35 arranged in the vertical and horizontal directions for performing a pressing operation as a switch operation from the front side. In addition, a substrate 33 is provided on the base portion 32, and contact terminals 37 connected to a circuit (not shown) and spaced apart from each other at positions facing the full pressing operation portion 35 of the operation panel 31 of the substrate 33. Between each pressing operation portion 35 and the substrate 33, there is provided a pressing deformation portion 39 as an uneven portion for separating and contacting the contact terminals 37 and providing an operational feeling during the pressing operation. ing.

  The operation panel 31 includes a key sheet 41 as a surface operation unit having an operation surface 31a of the pressing operation unit 35, and a plunger sheet 43 capable of pressing the pressing deformation unit 39 by a pressing operation to the pressing operation unit 35. 30 are laminated in order from the outside of the opening 30a, and are joined by an adhesive, a double-sided PSA sheet or the like.

  The key sheet 41 of the operation panel 31 is made of a hard resin sheet formed in a flat plate shape by a resin that can transmit light and is elastically deformable, such as polycarbonate and PET. In this embodiment, the key sheet 41 has a strength that can hold the shape of the operation panel 31 and can be pressed.

  The key sheet 41 is provided with an operation surface 31a of the pressing operation unit 35 on a surface exposed from the opening 30a of the housing 30, and light can be blocked on a surface opposite to the operation surface 31a. A light shielding layer 41a made of a printing layer is provided. At a predetermined position of the pressing operation unit 35 or the like, the light-transmitting display unit 45 that can transmit light by removing the light-shielding layer 41a in various shapes such as characters and diagrams, that is, without the light-shielding layer 41a. Is formed.

  The translucent display unit 45 is disposed at a position corresponding to the radiation surface region 15 of the illumination sheet 10, and the light transmitted through the translucent display unit 45 is visible from the surface side of the operation panel 31. Yes. Here, the translucent display part 45 is provided with a colored translucent decorative print layer so that the translucent light is colored.

  The plunger sheet 43 of the operation panel 31 has a flat sheet-shaped portion 43b having a size including the pressing operation portions 35 at a plurality of positions of the key sheet 41, and a pressing operation on the surface of the sheet-shaped portion 43b facing the pressing deformation portion 39. And a plurality of plunger portions 43a each projecting at a position corresponding to the portion 35.

  The plunger sheet 43 is formed from polyurethane, polyester, polycarbonate, acrylic alone or a composite thereof, silicone rubber, or the like. The sheet-shaped portion 43b is formed to be thinner in order to form the operation panel 31 to be thin, and is formed to be significantly softer than the key sheet 41 in order to make it difficult to inhibit the elastic deformation of the key sheet 41. is doing. The plunger sheet 43 may be provided with notches (slits) to facilitate elastic deformation.

  On the other hand, the substrate 33 of the base portion 32 is made of a hard printed board, a flexible printed board, or the like, and is fixedly attached to the housing 30. A large number of circuits (not shown) are provided on the substrate 33, and contact terminals 37 are provided at positions corresponding to the pressing operation unit 35.

  In addition, the pressing deformation portion 39 as an uneven portion provided on the operation panel 31 side of the substrate 33 is a hollow three-dimensional shape that can be elastically deformed at each position corresponding to the pressing operation portion 35 and the radiation surface area 15 of the illumination sheet 10. A metal dome 47 as an elastic dome having The metal dome 47 is disposed on the substrate 33 so as to protrude toward the operation panel 31.

  The metal dome 47 is always in contact with one of the contact terminals 37 at the periphery, and is disposed in a state of being separated from the other contact terminal 37 at the center, and is pressed by the plunger portion 43 a, whereby the metal dome 47 contacts the contact terminal 37. 37 is configured to be connected.

  The illumination sheet 10 is disposed along the upper surface of the metal dome 47 and the upper surface of the substrate 33 and is fixed in close contact with each other.

  In this state, the radiation surface region 15 of the illumination sheet 10 is disposed on the metal dome 47, and the irregular reflection portion 25 of the core layer 21 is disposed at a position corresponding to the pressing operation portion 35 of the operation panel 31. Further, the tip of the plunger portion 43 a of the plunger sheet 43 is in contact with a part of the cladding layer 22 in the radiation surface region 15.

  Therefore, when the pressing operation part 35 is pressed and displaced, the radiation surface area 15 of the illumination sheet 10 together with the metal dome 47 is repeatedly deformed in the direction intersecting the surface and displaced toward the substrate 33 side. Yes.

  In such a cellular phone, when the light source 13 (not shown) fixed to the substrate 33 emits light and the light is guided by the core layer 21, the irregular reflection portion of the core layer 21 in the radiation surface region 15 on the metal dome 47. Light is radiated from the surface of the cladding layer 22 by being irregularly reflected by 25. With this light, the pressing operation unit 35 of the operation panel 31 is transmitted through the plunger sheet 43 from the back side, and the translucent display unit 45 is irradiated. And the light which permeate | transmitted the translucent display part 45 is visually recognized from the surface side of the key sheet 41. FIG.

  In order to perform the pressing operation, a part of the plurality of pressing operation portions 35 of the operation panel 31 is pressed from the operation surface 31 a side of the key sheet 41. Then, the operation panel 31 is elastically deformed by the elasticity of the key sheet 41, the plunger portion 43a of the plunger sheet 43 is lowered, and the pressing deformation portion 39 is pressed by the plunger portion 43a. Then, the metal dome 47 is pressed through the illumination sheet 10, and the metal dome 47 is elastically deformed together with the illumination sheet 10, and a click operation feeling is obtained. The process is executed.

  According to the mobile phone as described above, the same effect as that of the first embodiment is obtained by the illumination sheet structure including the illumination sheet 10 and the base portion 32, and a rough surface or unevenness is provided on the arrangement surface 32 a of the base portion 32. And so on, regardless of the surface properties, the light guided in the core layer 21 is not easily attenuated in regions other than the predetermined radiation surface region 15, and strong light is emitted in the predetermined radiation surface region 15. Can be radiated.

  Moreover, since the metal dome 47 protrudes between the radiation surface region 15 of the illumination sheet 10 and the substrate 33, and the radiation surface region 15 of the illumination sheet 10 is disposed along the metal dome 47, the radiation surface Light can be easily emitted from the core layer 21 in the region 15.

  Here, the arrangement surface 32a of the illumination sheet 10 has a flat portion formed from the surface of the substrate 33 and an uneven portion formed from the surface of the metal dome 47 of the pressing deformation portion 39, and the radiation surface region 15 of the illumination sheet 10 is formed as an uneven portion. Is arranged. The boundary between the core layer 21 and the cladding layers 22 and 23 in the radiation surface region 15 has an uneven shape corresponding to the shape of the surface of the metal dome 47. Therefore, in the radiation surface region 15, the incident angle of the light traveling while reflecting in the core layer 21 with respect to the interface with the cladding layers 22, 23 can be made different from the portion disposed in the flat portion. Light can be easily emitted from the core layer 21 in the surface region 15.

  As a result, light from the light source can be efficiently emitted from the translucent display unit 45, and an efficient operation switch can be obtained while suppressing the number of light sources and the amount of light.

In the second embodiment, an example of a hard resin sheet has been described as the key sheet 41. For example, a through-hole is formed as a translucent display unit 45 on a flat thin sheet made of a metal such as stainless steel. It may be made of other materials such as a sheet made of a composite material provided and encapsulating a translucent resin in the through hole.
[Embodiment 3]

  6 and 7 show the third embodiment. The third embodiment is an example in which an illumination sheet structure different from the second embodiment is used for a mobile phone as an operation switch.

  Here, compared with the second embodiment, the operation panel 31 is not provided, and instead, a push button sheet 51 in which a plurality of push buttons 49 are joined on the plunger sheet 43 is provided. The push button sheet 51 is covered with a hard casing 30 from the upper surface side, and each push button 49 is pressed in a state where the pressing operation surface 51 a is exposed from a plurality of button openings 30 b provided in the casing 30. Arranged to be possible. Each push button 49 is provided with a flange portion 49a, and this flange portion 49a is accommodated in an enlarged diameter portion 30c provided on the base portion 32 side of the button opening 30b. The push button sheet 51 is supported by the housing 30 from the upper surface side.

  Further, the metal dome 47 is fixed to the substrate 33 by a metal dome fixing sheet 48 separately from the illumination sheet 10. This metal dome fixing sheet 48 is made of a resin film having flexibility, and fixes each metal dome 47 by covering a plurality of metal dome 47 together with the substrate 33 continuously from the convex surface side. . The metal dome fixing sheet 48 is provided with an opening 48 a at a position corresponding to the periphery of the top of each metal dome 47 so that the top of each metal dome 47 is exposed.

  The illumination sheet 10 is not provided with the cladding layer 22 on the push button sheet 51 side, and the surface of the core layer 21 is directly exposed. In this case, since the surface of the core layer 21 is in contact with an air layer having a refractive index lower than that of the cladding layer 22, the light guided through the core layer 21 is transmitted between the interface between the core layer 21 and the air layer, the core layer 21, and the core layer 21. The light is guided while being reflected from the interface with the cladding layer 23.

  Note that the irregular reflection portion 25 of the core layer 21 is disposed at a position corresponding to the pressing operation portion 35 of the push button 49.

  Others are the same as in the second embodiment.

  Even with such a configuration, the same effects as those of the second embodiment can be obtained. For example, even if a rough surface, unevenness, or the like is present on the arrangement surface 32a of the base portion 32, the surface properties thereof can be improved. Regardless, the light guided in the core layer 21 can be made difficult to be emitted in a region other than the predetermined radiation surface region 15.

  By the way, in this Embodiment 3, the cladding layer 23 of the illumination sheet 10 is arrange | positioned in contact with the surface of the metal dome fixing sheet | seat 48 which covers the board | substrate 33 and the metal dome 47 continuously. Even in such a case, when the cladding layer 23 is present, the surface roughness of the metal dome fixing sheet 48 is rough or the metal dome fixing sheet 48 is formed of a material having a higher refractive index than the core layer 21. Even if it is a case, it does not affect the light guide performance of the light which guides the inside of the core layer 21 at all.

It is a top view of the illumination sheet structure of Embodiment 1 of this invention. It is AA sectional drawing of FIG. 1 of the same Embodiment 1. FIG. It is BB sectional drawing of FIG. 1 of the illumination sheet of the same Embodiment 1. FIG. It is a fragmentary top view of the mobile telephone of Embodiment 2 of this invention. It is CC sectional drawing of FIG. 4 of the Embodiment 2. FIG. It is a partial top view of the mobile phone of Embodiment 3 of this invention. It is DD sectional drawing of FIG. 6 of Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Illumination sheet 11 Support base body 13 Light source 15 Radiation surface area 21 Core layer 22, 23 Cladding layer 25 Diffuse reflection part 27 Light shielding layer 30 Case 31 Operation panel 32 Base part 33 Substrate 35 Press operation part 39 Press deformation part 41 Key sheet 43 Plunger Sheet 45 Transparent display 47 Metal dome 51 Push button sheet

Claims (7)

An illumination sheet in which light from a light source is guided through a sheet-like interior and radiated from a predetermined radiation surface area provided on one surface; and a substrate disposed in contact with the other surface of the illumination sheet; In the illumination sheet structure comprising:
The illumination sheet includes a sheet-like core layer through which the light is guided, and a surface of the core layer on the base side is covered with a clad layer having a lower refractive index than the core layer. Illuminated sheet structure.   2. The illumination sheet structure according to claim 1, wherein a surface of the core layer opposite to the base side is covered with the cladding layer.   3. The illumination sheet structure according to claim 1, wherein a surface of the core layer covered by the clad layer is a mirror surface.   The illuminating sheet structure according to any one of claims 1 to 3, wherein the core layer in the radiation surface region is provided with an irregular reflection portion for irregularly reflecting light guided in the core layer. The arrangement surface of the base on which the illumination sheet is arranged in contact has a flat portion and an uneven portion,
The radiation surface region is disposed in the uneven portion, and an interface between the core layer and the clad layer in the radiation surface region has an uneven shape corresponding to the uneven portion. The illumination sheet structure according to any one of claims 1 to 4. The arrangement surface of the substrate, which is arranged in contact with the illumination sheet, has a surface shape changing portion where the surface shape of the illumination sheet changes,
The thickness of the cladding layer is formed to be thicker than the surface shape change portion, and changes substantially corresponding to the surface shape of the surface shape change portion, whereby the interface between the cladding layer and the core layer The illumination sheet structure according to any one of claims 1 to 5, wherein is formed flatter than a surface shape of the surface shape changing portion. A surface operation unit that performs a pressing operation from the surface side, the illumination sheet structure according to any one of claims 1 to 6 disposed opposite to the surface operation unit, and supplying light to the illumination sheet An operation switch with a light source to
The surface operation unit has a translucent display unit configured to transmit light from the radiation surface region and be viewed from the surface side at a position corresponding to the radiation surface region of the illumination sheet,
The base portion is provided with an elastic dome having a hollow three-dimensional shape that can be elastically deformed at a position corresponding to the radiation surface region of the illumination sheet,
The illumination sheet is disposed along the surface of the base portion,
The operation switch is configured such that when the pressing operation is performed on the surface operation unit, the elastic dome is pressed and elastically deformed through the radiation surface area of the illumination sheet.

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