JP2010146988A - Member for push-button switch, and electronic device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a member for a push-button switch capable of uniformly and luminously illuminating a button-pushing portion, and to provide an electronic device using it. <P>SOLUTION: In the member for a push-button switch 50 at least containing a plurality of key tops 2 and a transparent light guide plate 30 fitted at rear sides of the key tops 2, a lens sheet 20 is arranged between the key tops 2 and the transparent light guide plate 30, and a lens part 21 concentrating light passing through inside the transparent light guide plate 30 and illuminating it toward the key tops 2 is fitted at a position facing to the key tops 2 on the lens sheet. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a member for a push button switch suitably used for an electronic device and the like and an electronic device using the same.

  In recent years, as a push button switch member typified by an electronic apparatus such as a mobile phone or a portable information terminal device, an illuminated push button switch having an illumination function capable of ensuring the visibility of a key top portion in a dark place is often used. For this reason, there is a strong demand for a molded illumination pushbutton switch member having uniform illumination and high brightness.

  In response to this problem, a push button switch member used for illumination of the following electronic devices has been proposed. For example, a plurality of operation keys for operating the device, a plurality of switching elements that are disposed below the plurality of operation keys and that are switched by pressing the operation keys, and disposed between the operation keys and the switching elements The light guide plate is a member for a push button switch, which introduces light incident from a light source arranged on the side surface or the peripheral portion of the light guide plate and diffuses the light in the light guide plate, thereby lowering the operation key on the lower surface of the operation key. An invention is known in which light is projected from below and light is supplied to the surface of the operation key from below. (For example, see Patent Document 1).

  The following push button switch members are also known. A member for a push button switch having a key top portion and a base portion integrally formed of transparent silicone rubber, and a light guide plate arranged immediately below the base portion includes an LED or the like between the push button switch member and the circuit board. The surface of the key top portion is illuminated by supplying light from the light emitting source (see, for example, Patent Document 2).

JP 2001-167655 A (claims, etc.) Japanese Patent Laid-Open No. 08-273474 (claims)

  However, the conventional illuminated pushbutton switch member has the following problems. In the case of the member for a push button switch disclosed in Patent Literature 1 and Patent Literature 2, it is possible to realize a certain level of clear illumination of the push button portion. However, in such a pushbutton switch member, light is incident from the side end face of the light guide plate and the light is propagated uniformly throughout the light guide plate using reflection inside the light transmissive light guide plate. The light emitted from the light emitting surface that has a large variation in the in-plane light quantity distribution. For this reason, it is difficult to uniformly illuminate the surface of the push button portion, and there is a problem that uneven illumination or uneven brightness tends to occur. Further, only part of the light emitted from the light source can contribute to improving the visibility of the push button portion, and even when large power consumption is used, the luminance is low and the visibility of the push button portion is reduced. Furthermore, high brightness cannot be realized when only a specific character portion of the push button is strongly illuminated, or when it is attempted to ensure visibility by illumination even in the daytime when the outside light is strong.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a member for a push button switch capable of illuminating the push button portion more uniformly and with high brightness, and the push button thereof. An object of the present invention is to provide an electronic device using a switch member.

  To achieve the above object, the present invention provides a pushbutton switch member including at least a plurality of key tops and a light transmissive light guide plate provided on the back side of the key top, the key top and the light transmissive light guide plate. A lens sheet is arranged between the lens and the lens sheet, and the lens sheet collects the light that has passed through the translucent light guide plate at a position facing the key top and illuminates it toward the key top. It is a member for a push button switch provided with a portion.

  By using the push button switch member as described above, the push button switch member can illuminate the key top portion more uniformly and with high brightness. In other words, the lens sheet disposed between the key top and the light transmissive light guide plate collects light that has passed through the light transmissive light guide plate at a position facing the key top and heads toward the key top. After the push button switch member is mounted on the exterior case, the light from the light source is incident on the lens sheet through the translucent light guide plate, and then the lens portion of the lens sheet. Since the direction of the light is corrected, the light that was originally not excellent in directivity is collected and the light emitted to the key top does not vary in the emission direction. For this reason, it is possible to uniformly illuminate the key top portion of the push button switch member, and uneven illumination or luminance unevenness hardly occurs. Further, the light from the light source becomes uniform parallel light through the lens sheet and contributes to improving the visibility of the key top, so that the illumination energy can be increased without increasing the illumination energy. Thus, compared with a structure in which a conventional lens sheet is not disposed, uniform illumination and high brightness can be easily obtained, so that the visibility of the key top portion can be improved.

  In another invention, in addition to the above-described invention, on the back side of the lens sheet, the light to be emitted from the translucent light guide plate is reflected to the inside of the translucent light guide plate to the non-lens part other than the lens part. This is a push button switch member provided with a light reflecting layer.

  By using such a pushbutton switch member, when the light from the light source is guided while being reflected inside the translucent light guide plate, the light that has jumped out to the non-lens portion is reflected, and the light is transmitted again. It works to return to the inside of the light guide plate. For this reason, the light leaking from the non-lens portion is reduced, and the key top of the push button switch member can be efficiently illuminated through the lens portion.

  In addition to the above-described invention, another invention is a pushbutton switch in which a low refractive index layer made of a material having a lower refractive index than that of the lens sheet is provided on a non-lens part other than the lens part on the back side of the lens sheet. It is used as a member.

  By setting it as such a member for pushbutton switches, the light from a light source can illuminate the key top of the member for pushbutton switches efficiently through a lens part.

  In another invention, in addition to the above-described invention, the translucent light guide plate passes through the interior of the translucent light guide plate at a position facing the key top on at least one of the front side and the back side. The push button switch member is provided with a light diffusing portion for diffusing incoming light to illuminate the key top.

  By using such a pushbutton switch member, the light from the light source is reflected toward the surface of the light transmissive light guide plate by the light diffusing portion of the light transmissive light guide plate. It is possible to improve the performance.

  In another invention, in addition to the above-described invention, a push button switch member is provided in which a light diffusing sheet is provided between the translucent light guide plate and the lens sheet to increase the uniformity of light.

  By setting it as such a member for pushbutton switches, the light radiate | emitted from the translucent light-guide plate can be spread | diffused planarly with a light-diffusion sheet, and the intensity | strength of light can be made uniform. For this reason, uniform illumination and high luminance can be easily obtained, and the visibility of the key top can be improved.

  In another invention, in addition to the above-described invention, the lens sheet is a member for a push button switch which is a Fresnel lens sheet.

  For this reason, the light from the light source can be sufficiently guided, and the electronic device equipped with the push button switch member can be thinned.

  According to the present invention, there is provided an electronic apparatus using the pushbutton switch member according to any one of claims 1 to 6.

  For this reason, it becomes an electronic device which can illuminate the key top part more uniformly and with high luminance.

  Key top materials used for the pushbutton switch member according to the present invention include polyester resin, polycarbonate resin, acrylonitrile butadiene styrene resin (ABS resin), epoxy resin, phenol resin, acrylic resin, urethane resin, silicone Examples thereof include materials such as resin, polyvinyl chloride resin, polystyrene resin, polyarylate resin, polymethylpentene resin, polyurethane resin, polyethylene resin, polypropylene resin, polyphenylene ether resin, polyacetal resin, polysulfone resin, and polyetherimide resin. These resins have a transparent layer that efficiently transmits visible light so that the decorative layer is formed by various layers provided on the back surface of the key top, and the decorative layer can be visually recognized from the surface of the key top. Must be high material. For this reason, a completely transparent material is preferable, but it is more preferable that it has a transparency of at least 70% in terms of visible light transmittance. Furthermore, in consideration of processability, it is more preferable to use a polycarbonate resin or an acrylic resin. However, the above-mentioned resin material is only an example, and other resin materials may be adopted. The resin material may be one kind of resin material as described above or a mixture of two or more kinds of resin materials. In addition, when the push button switch member according to the present invention is a letter-illuminated type, a metal material, glass, ceramics, or the like can be used as a material constituting the key top. As the metal material, for example, metals such as stainless steel, aluminum, magnesium, copper, zinc, titanium, and alloys thereof can be suitably used.

  ADVANTAGE OF THE INVENTION According to this invention, the electronic device using the member for pushbutton switches which can illuminate a pushbutton part more uniformly and with high brightness | luminance, and the member for pushbutton switches can be provided.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a push button switch member and an electronic apparatus using the push button switch member according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the preferred embodiments described below.

(First embodiment)
FIG. 1 is a perspective view of a cellular phone (one form of electronic equipment) 100 including a pushbutton switch member 50 according to the first embodiment of the present invention as viewed from the operation surface side. FIG. 2 is a cross-sectional view of the push button switch member 50 shown in FIG.

  As shown in FIG. 1, the cellular phone 100 includes a pushbutton switch member 50, a circuit board (hereinafter referred to as “board”, not shown) disposed on the back surface thereof, and one of the above pushbutton switch members 50. And a light source disposed on the substrate in the vicinity of the end face. In this embodiment, the light source is an LED. For example, a white LED is preferable as the LED, but a blue LED or a red LED may be used. A plurality of types of LEDs may be used. For example, white light may be obtained from LEDs of three colors R, G, and B.

  As shown in FIG. 2, the pushbutton switch member 50 is formed by laminating a keytop sheet 10 including the keytop 2, a lens sheet 20, and a translucent light guide plate 30. The key top sheet 10 is preferably a polyester resin sheet, a polyethylene terephthalate resin sheet, an acrylic resin sheet, or a polycarbonate resin sheet. A decorative layer having a pattern such as letters, numbers, or a pattern may be formed on the entire surface or a part of the surface or the bottom surface of the key top 2. The method for forming the decoration layer is not particularly limited, and the decoration layer can be formed by a known method using ink or paint. In order to improve the fixability, adhesion, color development, etc. of ink or paint, it is preferable to modify the surface or bottom surface of the key top 2 by applying various known surface treatments in advance. By forming the decorative layer, the aesthetic effect of the key top sheet 10 can be improved. When a decoration layer is formed on the surface of the key top 2, it is preferable to form a protective layer made of a transparent resin on the outer surface of the decoration layer. If such a protective layer is formed, the decorative layer can be effectively protected from damage.

  The lens sheet 20 concentrates the light emitted from the surface of the translucent light guide plate 30 to uniformly illuminate the key top 2 of the pushbutton switch member 50 and to increase the illumination brightness of the key top 2. It is a member. In this embodiment, the lens sheet 20 is formed from a translucent substrate. As the translucent substrate, a flexible thermoplastic resin such as an acrylic resin sheet, a polycarbonate resin sheet, a polystyrene resin sheet, a polyester resin sheet, a polyethylene terephthalate resin sheet, or a polybutylene terephthalate resin sheet is preferably used. In addition, polyfunctional urethane acrylates crosslinked with ultraviolet rays or electron beams, acrylates such as polyester acrylate, or transparent resins having flexibility such as unsaturated polyester, or acrylics such as polymethyl methacrylate and polymethyl acrylate. An acid ester or a methacrylic acid ester alone or a copolymer resin may be used. Further, a composite of these thermoplastic resins and cross-linked resins may be used. A suitable thickness of the lens sheet 20 is in the range of 150 μm or less, and a particularly preferred thickness is 50 μm. The translucency required for the translucent substrate must be selected so that the emitted light is transmitted to the minimum to the extent that it does not hinder the use of each application, and colorless and transparent are the most desirable. May be colored and transparent.

  The translucent light guide plate 30 is a flat plate that emits light emitted from a light source disposed on the substrate from the surface thereof toward the key top 2 of the push button switch member 50, and is preferably an acrylic resin. A translucent member made of polycarbonate resin (PC). However, the translucent light guide plate 30 is made of resin other than acrylic resin and polycarbonate resin (PC), for example, polyethylene terephthalate resin (PET), polypropylene resin (PP), polymethyl methacrylate resin (PMMA), benzyl methacrylate resin, MS It may be made of a resin or an optically transparent resin such as cycloolefin polymer (COP).

  Moreover, the manufacturing method in particular of the translucent light-guide plate 30 is not restrict | limited, A well-known technique can be used. For example, it is manufactured by cast molding, extrusion molding, injection molding, press molding or the like using a transparent resin raw material.

  FIG. 3 is an enlarged cross-sectional view showing the configuration of the region B indicated by the alternate long and short dash line in FIG.

  As shown in FIG. 3, the lens sheet 20 disposed between the key top sheet 10 and the translucent light guide plate 30 is provided with a lens portion 21 at a position facing the key top 2. The lens sheet 20 can efficiently emit scattered light incident from the back surface of the lens portion 21 facing the key top 2 in the direction perpendicular to the key top 2 from the front surface by controlling the optical path. In the present embodiment, one or both surfaces of the lens sheet 20, particularly those having the lens portion 21 having an uneven structure on one surface can be preferably used. The concavo-convex structure forming the lens portion 21 may be any structure that exhibits a function of controlling the optical path of the light transmitted through the lens sheet 20 and condensing the transmitted light toward the top surface of the key top 2. Examples of the concavo-convex structure include, for example, a plurality of linear grooves or protrusions such as a triangular cross section arranged in a stripe shape, a lattice shape, a concentric circle shape, or a spiral shape, a triangular pyramid, a quadrangular pyramid, other polygonal pyramids, For example, a plurality of cone-shaped microprotrusions having a bottom shape such as a cone are arranged in a dot shape. Note that the linear or dotted uneven structure may be a spherical lens, an aspherical lens, a semi-cylindrical lens, or the like, and may have an appropriate lens form. In particular, a Fresnel lens sheet can be suitably used in order to sufficiently guide the light from the light source and reduce the thickness of the push button switch member.

  For example, the lens sheet 20 having the linear or dot-like concavo-convex structure of the lens portion 21 is formed by filling a mold formed so as to form a predetermined concavo-convex structure with a resin solution or a resin-forming monomer. And if necessary, it can be carried out by an appropriate method such as a method of polymerizing and transferring the concavo-convex structure of the mold, or a method of transferring the concavo-convex structure by thermocompression bonding a resin sheet to the mold. Note that the lens sheet 20 may be formed as two or more overlapping layers of the same or different types of resin layers, such as those obtained by adding the lens portion 21 to the sheet.

  The light transmissive light guide plate 30 is provided with a light diffusion portion 31 at a position facing the key top 2 of the key top sheet 10 on at least one of the front side and the back side. The light diffusing unit 31 is configured to efficiently emit light to the lens sheet 20 on the surface side of the translucent light guide plate 30. In the embodiment of the present invention, as shown in FIG. 3, a plurality of cone-shaped concave light diffusion portions 31 are formed on the back surface of the light-transmissive light guide plate 30. However, in place of the single-sided cone-shaped concave portion, a large number of minute concavo-convex structures may be provided on one side or both sides of the translucent light guide plate 30. The shape of the concavo-convex structure is not particularly limited, and may be any shape such as a round dot, a square dot, or a chain dot. Further, it may be formed in a stripe shape instead of a dot. Moreover, it is good also as dot-like printing, such as white. Further, scattering particles may be arranged in the diffusion part 31. As a method of forming the light diffusing portion 31, a known method can be used. For example, a method of forming a convex body that constitutes the light diffusing portion 31 on the front surface or the back surface of the light transmissive light guide plate 30 in advance or a transparent material. A method of printing a convex body in a subsequent process of the optical light guide plate 30 can be used.

  Further, on the back side of the lens sheet 20, a light reflecting layer 28 is provided in a portion other than the lens portion 21, that is, in the non-lens portion 25. The light reflecting layer 28 is a layer that reflects light to be emitted from the translucent light guide plate 30 to the inside of the translucent light guide plate 30. As a method for forming the light reflecting layer 28, a known method can be used. For example, titanium dioxide, aluminum, etc., which are pigments having high concealment and high whiteness on the back side of the non-lens portion 25 of the lens sheet 20. A white layer in which the above powder is dispersed may be formed by painting or the like, or a metal thin film layer may be formed by plating or vapor-depositing a metal such as aluminum, chromium or silver. For this reason, when the light from the light source is guided while being totally reflected in the translucent light guide plate 30, the light that jumps out from the non-lens portion 25 is reflected and returned to the translucent light guide plate 30 again. Working. Therefore, light leaking from the non-lens portion 25 is reduced, and the key top 2 of the pushbutton switch member 50 can be efficiently illuminated through the lens portion 21.

  In such a push button switch member 50, the light emitted from the light source is directly incident on the translucent light guide plate 30. Most of the incident light is irregularly reflected by the light diffusing portion 31 provided on the back surface of the translucent light guide plate 30 and enters the lens sheet 20. The lens sheet 20 condenses incident light by the lens unit 21, and parallel light is irradiated from the lens unit 21 to the key top 2. For this reason, it is possible to uniformly illuminate the key tops 2 of the pushbutton switch member 50, and uneven illumination or luminance unevenness does not occur. Further, since the light from the light source becomes uniform parallel light, it is possible to increase the luminance of the illumination without wasting illumination energy and contribute to the improvement of the visibility of the key top 2.

(Second embodiment)
Next, a pushbutton switch member 60 according to a second embodiment of the present invention will be described.

  The pushbutton switch member 60 according to the second embodiment has a common part with the pushbutton switch member 50 according to the first embodiment described above. In the following description of the second and subsequent embodiments, the common parts are denoted by the same reference numerals as those in the first embodiment, and the parts having the same structure are duplicated. Description is omitted.

  FIG. 4 is an enlarged cross-sectional view showing an enlarged configuration similar to the region B indicated by the alternate long and short dash line in FIG. 2 in the pushbutton switch member 60 according to the second embodiment of the present invention.

  In the second embodiment, unlike the first embodiment, in the pushbutton switch member 60, a light diffusion sheet for increasing the uniformity of light between the translucent light guide plate 30 and the lens sheet 20. 35 is provided. Further, on the back side of the lens sheet 20, a low refractive index layer 29 made of a material having a lower refractive index than that of the lens sheet 20 is provided in place of the light reflecting layer 28. The low refractive index layer 29 is preferably a coating layer formed from a fluorine-based material or a double-sided tape. By using such a pushbutton switch member 60, the light emitted from the translucent light guide plate 30 is diffused in a planar shape to make the light intensity uniform before entering the lens sheet 20. Can do. For this reason, more uniform illumination and high brightness can be easily obtained, and the visibility of the key top 2 can be improved. The light diffusion sheet 35 is used for the purpose of diffusing the emitted light from the translucent light guide plate 30 to make the emitted light uniform and improving the visibility, etc., so that the polarization characteristic of the emitted light is not eliminated as much as possible. Are preferably used. As the light diffusion sheet 35 having excellent polarization maintaining property, for example, a sheet whose surface is roughened by buffing or the like, inorganic fine particles such as silica, alumina, titania, zirconia, indium oxide, or crosslinked or uncrosslinked Examples thereof include a resin sheet containing transparent fine particles such as organic fine particles such as a polymer.

  In such a pushbutton switch member 60, light emitted from the light source is directly incident on the translucent light guide plate 30. Most of the incident light is diffusely reflected by the light diffusion portion 31 provided on the back surface of the translucent light guide plate 30 and is incident on the light diffusion sheet 35. The light diffusion sheet 35 diffuses incident light in a planar shape to make the light intensity uniform, and then enters the lens sheet 20. The lens sheet 20 condenses the light diffused in a planar shape by the lens unit 21, and the parallel light is irradiated from the lens unit 21 to the key top 2. For this reason, the key top 2 of the member 60 for pushbutton switches can be illuminated uniformly. As a result, uneven illumination or uneven brightness between the key tops 2 hardly occurs. Further, since the light from the light source becomes uniform parallel light, light energy can be used for illumination of the key top 2 without waste, and the visibility of the key top 2 can be further improved.

  The pushbutton switch members 50 and 60 and the electronic device 100 using the pushbutton switch member according to the embodiment of the present invention have been described above. However, the pushbutton switch members 50 and 60 and the pushbutton switch member according to the present invention are described. The electronic device 100 using the members is not limited to the above-described embodiments, and can be implemented in various modifications.

  For example, the shape, size, arrangement, or number of the lens portions 21 can be appropriately changed according to the required design of the key top 2.

  Further, instead of the key top sheet 10, a lens sheet 20 having a lens portion 21 corresponding to each key top 2 may be formed immediately below the base film 10.

  INDUSTRIAL APPLICABILITY The present invention can be used in industries that manufacture or use a pushbutton switch member and an electronic device that uses the pushbutton switch member.

It is the perspective view which looked at the mobile telephone (one form of electronic device) provided with the member for pushbutton switches which concerns on the 1st Embodiment of this invention from the operation surface side. It is the sectional view on the AA line of the member for pushbutton switches shown in FIG. It is an expanded sectional view which expands and shows the structure of the area | region B shown by the dashed-dotted line of FIG. It is an expanded sectional view which expands and shows the structure similar to the area | region B shown by the dashed-dotted line of FIG. 2 in the member for pushbutton switches which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

2 ... key top 10 ... key top sheet 20 ... lens sheet 21 ... lens part 25 ... non-lens part 28 ... light reflection layer 29 ... low refractive index layer 30 ... translucent light guide plate 31 ... light diffusion part 35 ... light diffusion sheet 50, 60: Pushbutton switch member 100: Mobile phone (electronic device)

Claims (7)

A member for a push button switch including at least a plurality of key tops and a translucent light guide plate provided on the back side of the key tops,
A lens sheet is disposed between the key top and the translucent light guide plate, and the light passing through the translucent light guide plate is collected on the lens sheet at a position facing the key top. A member for a push button switch, comprising a lens portion for illuminating and illuminating the key top.   On the back side of the lens sheet, a non-lens portion other than the lens portion is provided with a light reflecting layer that reflects light to be emitted from the light transmissive light guide plate to the inside of the light transmissive light guide plate. The member for a push button switch according to claim 1 characterized by the above-mentioned.   2. The pushbutton switch according to claim 1, wherein a low refractive index layer made of a material having a lower refractive index than that of the lens sheet is provided on a non-lens portion other than the lens portion on the back side of the lens sheet. Materials.   The translucent light guide plate diffuses light that has passed through the translucent light guide plate to a position facing the key top on at least one of the front side and the back side of the translucent light guide plate. The pushbutton switch member according to any one of claims 1 to 3, further comprising a light diffusing portion for illuminating the top.   Furthermore, the light-diffusion sheet for improving the uniformity of light is provided between the said translucent light-guide plate and the said lens sheet, The any one of Claim 1 to 4 characterized by the above-mentioned. A member for a push button switch.   The member for a push button switch according to any one of claims 1 to 5, wherein the lens sheet is a Fresnel lens sheet.   An electronic apparatus comprising the pushbutton switch member according to any one of claims 1 to 6.

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