JP2011018535A - Light guide sheet switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide sheet switch capable of: maintaining thickness of the whole light guide body including a pushing part at a fixed level by forming the pushing part corresponding to a key switch in the light guide body with a material harder than the material of the other light guide part; and achieving improved effects for clicking feeling and a clicking operation of the key switch.SOLUTION: In the light guide sheet switch 11 including a sheet switch body 12 preparing the key switch 25 on a base material 22 and the light guide body 13 prepared on the sheet switch body 12, the light guide body 13 includes a light guide body part 28, and the pushing part 29 prepared on a part corresponding to the key switch 25, and the pushing part 29 is formed with a material harder than the material of the light guide body part 28.

Description

  The present invention relates to a light guide sheet switch constituting a key input unit of various electronic devices.

  Conventionally, many key input units of thin electronic devices such as cellular phones and portable information terminals are configured using a light guide sheet switch having an illumination function. Such a light guide sheet switch includes a key switch formed on a base material, a light guide disposed on the key switch, and a light source (light emitting element) disposed on one end of the light guide. (Refer to Patent Document 1).

  FIG. 7 shows an example of a cross-sectional structure of a general light guide sheet switch 1. The light guide sheet switch 1 includes a sheet switch body 7 in which a key switch 5 including a fixed contact 3 and a movable contact 4 is formed on a sheet-like substrate 2, and the key switch 5 is covered with a sheet material 6. A light guide 8 disposed on the sheet switch body 7 and provided with a projection 9 at a portion facing the key switch 5, and a light source (not shown) for making light incident on the light guide 8 Is done.

  The light guide 8 including the protrusions 9 is formed of a relatively soft resin material having translucency. Moreover, the thickness of the light guide 8 may be limited in order to reduce the thickness of the light guide sheet switch 1.

JP 2004-69751 A

  In the light guide sheet switch 1 having the above-described configuration, the light guide efficiency may be reduced when the light guide 8 including the protrusions 9 is thinned. Further, since the protrusion 9 is integrally formed of the same soft resin material as that of the light guide 8, there is a problem that the click feeling with respect to the key switch 5 is not sufficiently obtained and the operability is poor.

  Accordingly, an object of the present invention is to form the pressing portion corresponding to the key switch in the light guide with a material harder than other light guiding portions, thereby reducing the thickness of the entire light guide including the pressing portion. An object of the present invention is to provide a light guide sheet switch that can be made constant, and that can improve the click feeling and click operability of a key switch.

  In order to solve the above problems, a light guide sheet switch of the present invention includes a sheet switch body in which a key switch is disposed on a base material and a light guide body disposed on the sheet switch body. In the sheet switch, the light guide body includes a light guide main body portion and a pressing portion provided in a portion corresponding to the key switch, and the pressing portion is formed of a material harder than the light guide main body portion. It is characterized by being.

  According to the light guide sheet switch of the present invention, the light guide disposed on the sheet switch body corresponds to the light guide body and the individual key switches, and is formed of a material harder than the light guide body. Therefore, the corresponding key switch can be switched reliably and accurately while maintaining the bending deformability during the click operation.

  Moreover, since it can form so that the thickness of a light guide main-body part may become substantially the same thickness as a press part, improvement of the illumination efficiency accompanying the increase in the amount of light guides is achieved.

  In addition, since the pressing portion and the light guide main body portion are integrally formed and can be formed on a flat surface, it is easy to incorporate into a thin electronic device such as a mobile phone.

It is a disassembled perspective view of the light guide sheet switch which concerns on this invention. It is sectional drawing of the said light guide sheet switch. It is principal part sectional drawing of the said light guide sheet switch. It is sectional drawing of the press part formed in the taper shape. It is sectional drawing of the press part formed in reverse T shape. It is sectional drawing of the light guide which coat | covered the protective sheet. It is principal part sectional drawing of the conventional light guide sheet switch.

  Hereinafter, an embodiment of a light guide sheet switch according to the present invention will be described in detail with reference to the accompanying drawings. As shown in FIGS. 1 and 2, the light guide sheet switch 11 of the present invention includes a sheet switch main body 12 and a light guide body 13 placed on the sheet switch main body 12.

  The sheet switch body 12 includes a base material 22 and a plurality of key switches 25 arranged and formed on the base material 22 at predetermined intervals. As the base material 22, a thinly molded epoxy resin plate or flexible (FPC) plate is used, and a light source (light emitting element) 27 for illuminating the entire sheet switch body 12 is disposed at the end. The key switch 25 includes a fixed contact 23 patterned on the base material 22 and a movable contact 24 disposed on the fixed contact 23, and a thin sheet material 26 having an adhesive surface on the back surface side. The movable contact 24 is fixed on the substrate 22.

  For example, when the base material 22 is formed as a sheet switch of an operation panel of a mobile phone, it is formed in a shape and size substantially the same as the operation panel, and numeric keys, alphabet keys, other function keys, etc. A plurality of fixed contacts 23 are provided in accordance with the locations to be arranged. The movable contact 24 is formed in a dome shape made of a thin metal material in order to obtain an appropriate click feeling, and is arranged so as to cover the fixed contact 23 above. In addition, the upper surface of the movable contact 24 is mirror-finished to increase the reflectivity in one example, and visibility is improved by reflecting light guided by the light guide 13 described later.

  As shown in FIG. 3, the sheet material 26 is formed along the shape of the movable contact 24. When the sheet switch body 12 is actually assembled, a transparent adhesive is uniformly applied to the entire back surface of the sheet material 26, and the movable contact 24 is adhered and held, whereby the fixed contact 23 is formed. After aligning with the upper surface of the substrate 22, the substrate 22 is coated so as to be in close contact. Note that the sheet material 26 can also be made to adhere to the back surface of the movable contact 24 directly and adhere to the outer shape of the movable contact 24 by means such as heating and pressurization.

  As shown in FIGS. 1 and 2, the light emitting element 27 is a side light emitting type light emitting diode, and the light emitting surface 27 a is directed to one side surface of the light guide 13 so as to be disposed on the outer peripheral portion of the base material 22. Be placed. The arrangement location and the number of the light emitting elements 27 are appropriately set according to the shape and size of the base material 22 and the number of arrangement of the key switches 25. For example, numeric keys or function keys such as a mobile phone are arranged. In the case of such a rectangular sheet switch, several sheets are arranged at equal intervals on at least one of the sides.

  As shown in FIG. 3, the light guide 13 includes a light guide main body 28 having substantially the same shape and plane size as the base material 22, and a pressing portion 29 provided in a portion corresponding to each key switch 25. It is formed in a flat plate shape. The light guide main body 28 is made of a resin material having relatively high light guide efficiency, such as urethane resin or silicone resin, while being relatively soft and flexible. The pressing portion 29 is made of a resin material used in the light guide main body portion 28, for example, a hard urethane resin or a hard silicone resin, but is formed using a resin material harder than the light guide main body portion 28. The Further, the light guide main body 28 and the pressing portion 29 can be formed by a combination of different materials. For example, the light guide body 28 is urethane resin and the pressing part 29 is acrylic resin, the light guide body 28 is silicone resin and the pressing part 29 is acrylic resin, the light guiding body 28 is urethane resin and the pressing part 29 is epoxy resin, It is possible to combine the light guide main body portion 28 with silicone resin and the pressing portion 29 with epoxy resin or the like. However, in any combination, the resin used for the pressing portion 29 needs to be harder than the resin used for the light guide main body portion 28.

  As shown in FIG. 3, the light guide body 13 having the above structure is bent downward by the light guide main body 28 around the light guide body 13 without being deformed by pressing from the P direction with a finger or the like. For this reason, the pressing force can be transmitted to the movable contact 24 as it is, and the click operation can be performed smoothly.

  The light guide 13 is formed by a two-color molding method using a mold for forming the light guide main body 28 and a mold for forming the pressing portion 29, and the light guide main body 28 and the pressing portion. 29 can be integrated with each other. In addition, after the flat light guide main body 28 is formed, a hole through which a portion corresponding to the key switch 25 of the light guide main body 28 is formed in a cylindrical shape is opened, and the hole is formed separately. It can also be formed by fitting a hard resin body made or filling and curing another resin material in the hole.

  Further, as shown in FIG. 4, the pressing portion 29 is formed in a taper shape such that the lower surface side contacting the top of the key switch 25 becomes narrower with respect to the top surface, so that the pressing force is applied to the top of the key switch 25. Can be concentrated. Further, as shown in FIG. 5, by forming the pressing portion 29 so that the cross section has an inverted T shape, the pressing surface in contact with the key switch 25 can be slightly widened, and the light guide main body portion 28. Since it can be prevented from coming off or falling off, durability and strength can be improved.

  The light guide body 13 includes a light guide main body 28 including a pressing portion 29 having a constant thickness, and can have a flat surface. In this way, by finishing the surface of the light guide 13 flat, as shown in FIG. 6, a rubber sheet that covers the moisture-proof transparent film member 30 or the function of each key switch 25 is applied. Combinations such as placement are easy. In addition, the clickability with respect to each key switch 25 can be improved by forming the dome-shaped protrusion 31 on the lower surface of the pressing portion 29.

  As described above, the pressing portion 29 uses a hardness or material different from that of the light guide main body portion 28, and is formed by fitting or filling the light guide main body portion 28 so that light can be transmitted. A light scattering effect due to refraction, reflection, or a difference in emission color occurs. As a result, an effect of facilitating identification of the position of each key switch 25 in the entire light guide 13 can be obtained. As a means for further enhancing such discrimination and giving a decorative property, a white dot pattern is printed around the pressing portion 29, various fluorescent agents, minute beads, etc. are provided inside the pressing portion 29. Or a light scattering agent can be contained.

  Further, the pressing portion 29 can be formed using a silicone material having translucency similar to that of the light guide main body portion 28 and increasing the density and the degree of compression of the silicone material itself. By forming the pressing portion 29 with such a light-transmitting material, a light guide direction and light guide rate substantially the same as those of the surrounding light guide main body portion 28 can be obtained, and a guide with excellent clickability can be obtained. It becomes a light body.

  Since the light guide body 13 having the above structure can form the light guide main body 28 so as to be approximately the same height as the thickness of the pressing portion 29, the light guide efficiency due to the increase in the amount of light guided around the pressing portion 29. The improvement effect is obtained. Moreover, since the press part 29 is the height substantially the same as the thickness of the light guide main-body part 28, the flat light guide 13 without an unevenness | corrugation can be comprised.

  The overall height of the light guide 13 is not particularly limited, but if it is in the range of 0.20 mm to 0.25 mm, the required light guide efficiency can be ensured, and the bending deformation that occurs when clicking is performed. It is possible to respond flexibly.

  On the sheet switch main body side, the upper surface of the movable contact 24 to which the sheet material 26 is in close contact is mirror-finished to provide a mirror-surface portion on the entire upper surface, or a concavo-convex portion or embossed surface that is subjected to fine concavo-convex processing. Accordingly, it is possible to improve the reflectance and the luminance by the light diffusion effect. The movable contact 24 is not limited to being formed of a metal material. For example, a resin plate having elasticity is embossed like a fixed contact and formed into a dome shape, and is electrically connected to the fixed contact 23 on the back surface. The movable contact electrode to be formed can be formed by plating or vapor-depositing a reflective metal film on the surface, or by applying a coating containing fine metal particles or glass particles having a light reflecting effect. By forming the portion constituting the movable contact 25 with such a resin plate, it is possible to obtain a soft click feeling that is different from the metal fixed contact as described above.

DESCRIPTION OF SYMBOLS 1 Light guide sheet switch 2 Base material 3 Fixed contact 4 Movable contact 5 Key switch 6 Sheet material 7 Sheet switch main body 8 Light guide body 9 Protrusion 11 Light guide sheet switch 12 Sheet switch body 13 Light guide body 22 Base material 23 Fixed contact 24 Movable contact point 25 Key switch 26 Sheet material 27 Light emitting element 27a Light emitting surface 28 Light guide body part 29 Pressing part 30 Film member 31 Projection part

Claims (6)

In a light guide sheet switch comprising a sheet switch body in which a key switch is disposed on a base material, and a light guide disposed on the sheet switch body,
The light guide body includes a light guide body portion and a pressing portion provided in a portion corresponding to the key switch, and the pressing portion is formed of a material harder than the light guide body portion. A light guide sheet switch characterized by The light guide sheet switch according to claim 1, wherein the pressing portion is formed of a resin material having a hardness higher than that of the light guide main body portion. The light guide sheet switch according to claim 2, wherein the resin material has translucency. The light guide sheet switch according to claim 1, wherein the pressing portion is formed integrally with the light guide main body portion. The light guide sheet switch according to claim 1, wherein the pressing portion has substantially the same height as the thickness of the light guide main body portion. The light guide sheet switch according to claim 1, wherein the front light guide main body portion has substantially the same thickness as the height of the pressing portion.

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