JP2010027537A - Sheet switch module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet switch module, constituted to enable accurate depression without shifts from a depression region, on a plurality of key switches arranged on a substrate, resulting in improved the switching operability and reliability. <P>SOLUTION: In the sheet switch module 20 comprises the substrate 22, the plurality of key switches 28 formed on the substrate 22, and a light guide sheet 31 arranged over the key switches 28, the light guide sheet 31 has lower face protrusions 33, having point contact with top portions 28a of a doom-shaped movable contacts 24 of the key switches 28, and columnar upper face protrusions 43 formed on the upper face side corresponding to the lower face protrusions 33. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  Conventionally, a thin and flat sheet switch is often used for a key input part of a thin electronic device such as a mobile phone or a portable information terminal. There is also an illuminated sheet switch module in which a light emitting element is combined with the sheet switch. This type of sheet switch module includes a substrate on which a conductive pattern is formed, a plurality of key switches disposed on the substrate, a light guide sheet disposed on the key switch, and one end of the light guide sheet. And a light emitting element to be arranged (see Patent Document 1).

  FIG. 6 shows an example of a sectional structure of the sheet switch module. The sheet switch module 10 includes a key switch 16 having a fixed contact 13 and a dome-shaped movable contact 14 on a substrate 12, a fixed sheet 15 for fixing the key switch 16 on the substrate 12, and a cover 15 covered with the fixed sheet 15. The light guide sheet 11 is placed through the top of the movable contact 14, and the side light emitting element 17 is disposed at one end of the light guide sheet 11. Further, on the light guide sheet 11, there is a case where a rubber sheet 18 on which a display unit 19 such as numerals and symbols is written in a portion corresponding to each key switch 16 is arranged.

In the sheet switch module 10 having the above configuration, in order to improve the click feeling of the key switch 16, there is a case where a protrusion is provided on the back surface side of the light guide sheet 11. By providing this protrusion so as to contact the top of the movable contact 14, the movable contact 14 can be easily pressed and switching can be improved.
JP 2004-69751 A

  In the sheet switch module 10 having the above-described configuration, switching is performed by pressing a portion of the light guide sheet 11 corresponding to the upper part of the place where each key switch 16 is disposed. Since 11 is flat, there is a problem that the pressing point is difficult to understand. For this reason, a rubber sheet provided with a protrusion at a portion corresponding to the key switch 16 is actually disposed on the light guide sheet 11 and used.

  However, when a rubber sheet is combined with the sheet switch module 10 separately, it is not easy to position the protrusion of the rubber sheet at a position corresponding to the key switch 16, and the rubber sheet may be disposed in a shifted state. . If the protrusion is displaced from the center of the key switch 16, not only the click feeling of the key switch 16 is impaired but also a switching failure may be caused.

  Therefore, an object of the present invention is to provide a structure for improving the operability and certainty of switching by making sure that pressing is possible without deviating from pressing areas on a plurality of key switches arranged on a substrate. Is to provide a sheet switch module.

  In order to solve the above problems, a sheet switch module according to the present invention is a sheet switch module comprising a substrate, a plurality of key switches formed on the substrate, and a pressing sheet disposed on the key switch. The pressing sheet includes a lower surface protrusion that makes point contact with the top of the key switch formed in a dome shape, and a columnar upper surface protrusion formed on the upper surface side at a position corresponding to the lower surface protrusion. Features.

  According to the seat switch module of the present invention, the effect of improving the click feeling of the key switch by providing the lower surface protrusion and the effect of preventing the positional deviation of the pressing point of the key switch by providing the upper surface protrusion are obtained. As a result, the operability and reliability of switching can be greatly improved.

  Hereinafter, embodiments of a seat switch module according to the present invention will be described in detail with reference to the accompanying drawings. As shown in FIGS. 1 and 2, the sheet switch module 20 of the present invention includes a substrate 22, a plurality of key switches 28 arranged on the substrate 22, and a light guide disposed on the key switches 28. A pressure sheet (light guide sheet) 31 having a property and a light emitting element 27 arranged toward one end of the light guide sheet 31 are configured.

  The substrate 22 is made of a thin molded epoxy resin plate or flexible (FPC) plate, and the light emitting element 27 is disposed at the end. Each key switch 28 is composed of a fixed contact 23 patterned on the substrate 22 and a movable contact 24 made of a tact spring disposed on the fixed contact 23, and a thin fixed sheet having an adhesive surface on the back surface side. 25, the movable contact 24 is fixed on the substrate 22.

  For example, when the substrate 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. are arranged. A plurality of the fixed contacts 23 are provided in accordance with the locations to be processed. 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.

  As shown in FIG. 2, it is desirable that the fixed sheet 25 has an embossed portion where the movable contact 24 is covered and held. When the key switch 28 is actually assembled, a transparent adhesive is uniformly applied to the entire back surface of the fixed sheet 25 including the embossed shape, and the movable contact 24 is adhered and held, whereby the fixed contact 23 is formed. After being aligned with the upper surface of the substrate 22, it is coated so as to be in close contact. The fixed sheet 25 is not provided with the embossed portion as described above in advance, but the movable contact 24 is directly adhered to the fixed sheet 25 as it is, and the outer shape of the movable contact 24 is applied by means such as heating and pressing. It is also possible to carry out close-fitting along.

  The light emitting element 27 uses a side light emitting type light emitting diode, and is arranged on the outer peripheral portion of the substrate 22 with its light emitting surface facing one side surface of the light guide sheet 31. The arrangement location and the number of the light emitting elements 27 are appropriately set according to the shape and size of the substrate 22 and the number of arrangement of the key switches 28. For example, numeric keys or function keys such as a mobile phone are arranged. In the case of such a rectangular sheet switch, several switches are arranged at equal intervals on at least one side.

  As shown in FIGS. 1 and 2, the light guide sheet 31 is a transparent or translucent thin plate member having substantially the same shape and plane size as the substrate 22, and a lower surface corresponding to each key switch 28 on the back surface side. A protrusion 33 is provided, and an upper surface protrusion 43 is provided on the surface side of the light guide sheet 31 corresponding to the lower surface protrusion 33. For the light guide sheet 31 including the lower surface protrusions 33 and the upper surface protrusions 43, for example, a material having high light guide properties such as acrylic resin, silicon resin, polycarbonate resin, or polyethylene terephthalate resin is used.

  The lower surface protrusion 33 is formed so as to protrude hemispherically from the back surface of the light guide sheet 31 toward the movable contact 24 of the key switch 28. The lower surface protrusion 33 is formed by a circular contour portion 35 that defines the pressing range of the movable contact 24, and a convex portion 36 that is thickly formed in the contour portion 35. Is lightly in contact with the top 28a of the key switch 28. The contour portion 35 and the convex portion 36 can be formed by screen printing a transparent resin material. For example, after the contour portion 35 is first formed by printing or the like, the convex portion 36 can be formed by printing such that the central portion is raised while a resin material is stacked in the contour portion 35.

  The upper surface protrusion 43 has the same circular contour portion 46 as the lower surface protrusion 33 on the surface of the light guide sheet 31, a side wall portion 44 that rises substantially perpendicularly from the contour portion 46, and an upper end of the side wall portion 44. The pressing surface 45 forms a columnar shape. The side wall 44 of the upper surface protrusion 43 is substantially the same as the thickness up to the top of the lower surface protrusion 33 and is formed to have a uniform thickness over the entire circumference. The pressing surface 45 is a flat surface that is parallel to the light guide sheet 31. The formation position of the upper surface protrusion 43 is set so that the center portion coincides with the tops of the key switch 28 and the lower surface protrusion 33 and the contour portion 46 is also aligned with the contour portion of the lower surface protrusion 33. As a result, the shaking of the key switch 28 can be minimized.

  The thickness of the lower surface protrusion 33 and the upper surface protrusion 43 differs depending on the thickness of the light guide sheet 31 and the setting of the stroke width required for the click operation, but when the thickness of the light guide sheet 31 is about 0.25 mm, the lower surface protrusion It is preferable that the thickness up to the center of 33 is about 0.15 mm and the thickness of the upper surface protrusion 43 is about 0.1 mm.

  By providing the upper surface protrusion 43 at a position corresponding to the lower surface protrusion 33, the pressing point of the key switch 28 becomes clear and the pressing surface 45 is formed as a flat surface. If so, the key switch 28 can be surely switched toward the fixed contact 23 even when the portion shifted from the central portion to the outer peripheral portion is pressed. In particular, since the edge is a right-angled edge from the outer peripheral edge of the pressing surface 45 to the side wall 44, even when a pressing force is applied to the outer peripheral edge, the upper surface protrusion 43 does not bend and deform, and the pressing force from above is applied. It can be transmitted straight to the lower movable contact 24. In addition, since the pressing surface 45 of the upper surface protrusion 43 has a flat cylindrical shape, even when the pressing surface 45 is pressed from an oblique direction shifted from the vertical direction, the key switch 28 is interposed via the lower surface protrusion 33. As a result, a pressing force is applied to the top portion 28a of the main body 28a, and switching can be performed accurately. In the present embodiment, the upper surface protrusion 43 is formed in a cylindrical shape in accordance with the lower surface protrusion 33, but may be formed in a prismatic shape such as a triangle or a square.

  FIG. 3 shows a cross-sectional configuration example when a rubber sheet 50 serving as an operation surface is disposed on the sheet switch module 20. The rubber sheet 50 is provided with a display unit 51 such as numerals and symbols by printing or a dot pattern in accordance with locations corresponding to the key switches 28 of the sheet switch module 20. The rubber sheet 50 is combined on the light guide sheet 31 so that the display unit 51 is aligned with the key switch 28. Since the upper surface protrusion 43 corresponding to each key switch 28 is provided on the upper surface of the light guide sheet 31, the position of the corresponding key switch 28 can be easily confirmed even from above the rubber sheet 50. In addition, since the pressing surface 45 of the upper surface protrusion 43 is in close contact with the back surface of the rubber sheet 50, a predetermined key switch is provided from the upper surface protrusion 43 through the lower surface protrusion 33 even on the rubber sheet 50 as described above. 28 can be reliably switched.

  Next, the light guide action in the sheet switch module 20 will be described. As shown in FIG. 1, the light guide sheet 31 is provided with a light receiving portion 34 that is recessed on one side so as to contain the light emitting surface 27 a of the light emitting element 27, and light received from the light receiving portion 34 The entire light guide sheet 31 can be illuminated uniformly and brightly. In this case, as shown in FIG. 4, spot-like light emission can be suppressed by applying a light shielding portion 41 to a part of the contour portion 35 of the lower surface protrusion 33.

  As shown in FIG. 5, the light shielding portion 41 is formed in an arc shape along a part of the contour portion 35. The light shielding portion 41 is formed to have a certain length and width along the inner surface of the contour portion 35. The length and width are set according to the light emission amount and distance of the light emitting element 27, but in order to suppress spot-like light diffusion, the length is ½ or less of the entire contour portion 35, and 1 It is preferable to set it to about / 4. Further, the width is preferably in the range of about ½ of the radius from the contour portion toward the center of the lower surface protrusion 33, and has a sector shape as a whole. In the present embodiment, as shown in FIG. 4, the light-shielding portion 41 has a light black ink on a part of the portion that curves inward of the contour portion 35 with respect to the direction facing the light emitting surface 27 a of the light emitting element 27. Was formed by printing. Further, the light shielding portion 41 may be formed so as to cover a part of the outer peripheral portion of the convex portion 36 from the contour portion 35. By providing the light-shielding portion 41 at such a position, as shown in FIG. 4, only the spot-like light diffusing action is achieved without hindering the progress of the light guided from the arrow direction in the light guide sheet 31. Can be suppressed.

  As described above, according to the sheet switch module 20 of the present invention, the lower surface protrusion 33 is provided on the back surface of the light guide sheet 31 corresponding to each key switch 28, and the upper surface corresponding to the lower surface protrusion 33 on the surface. By providing the protrusion 43, the click feeling is improved and the switching reliability is obtained. In particular, the upper surface protrusion 43 is formed in a columnar shape with the pressing surface 45 being flat, and the lower surface protrusion 33 is formed in a hemispherical shape so as to make point contact with the top of the key switch 28. It is possible to direct the pressing force received at the center position of the key switch 28. Thereby, if it is in the range of the said press surface 45, even if it is a case where it presses from a slightly inclined angle, switching operation can be performed reliably. Further, since the lower surface protrusion 33 and the upper surface protrusion 43 are integrally provided on the light guide sheet 31, the sheet switch module 20 can be used alone, and a separate operation panel such as the rubber sheet 50 can be used. Even in the case of providing a projection, it is not necessary to provide a projection or the like on such an operation panel.

It is a disassembled perspective view of the sheet switch module concerning the present invention. It is sectional drawing of the said sheet switch module. It is sectional drawing when a rubber sheet is combined with the said sheet switch module. It is sectional drawing which shows the light guide effect | action of the said sheet switch module. It is a top view of the said sheet switch module. It is sectional drawing of the conventional sheet switch module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sheet switch module 11 Light guide sheet 12 Substrate 13 Fixed contact 14 Movable contact 15 Fixed sheet 16 Key switch 17 Light emitting element 18 Rubber sheet 19 Display part 20 Sheet switch module 22 Substrate 23 Fixed contact 24 Movable contact 25 Fixed sheet 27 Light emitting element 27a Light emitting surface 28 Key switch 28a Top portion 31 Light guide sheet 33 Lower surface protrusion 34 Light receiving portion 35 Contour portion 36 Convex portion 41 Light shielding portion 43 Upper surface protrusion 44 Side wall portion 45 Press surface 46 Contour portion 50 Rubber sheet 51 Display portion

Claims (7)

In a sheet switch module comprising a substrate, a plurality of key switches formed on the substrate, and a pressing sheet disposed on the key switch,
The pressing sheet includes a lower surface protrusion that makes point contact with the top of the key switch formed in a dome shape, and a columnar upper surface protrusion formed on the upper surface side of a position corresponding to the lower surface protrusion. Sheet switch module. The sheet switch module according to claim 1, wherein the lower surface protrusion is formed in a hemispherical shape toward the top of the key switch. The sheet switch module according to claim 1, wherein the upper surface protrusion includes a side wall portion that rises substantially perpendicularly from the surface of the pressing sheet, and a flat pressing surface provided on the side wall portion. The sheet switch module according to claim 1, wherein the lower surface protrusion and the upper surface protrusion are formed in a circular shape centering on the top of the key switch. The sheet switch module according to claim 1, wherein the pressing sheet is formed of a light guide sheet having translucency, and a light emitting element is disposed at one end of the light guide sheet. The sheet switch module according to claim 1, wherein a light shielding member is provided around the lower surface protrusion. The sheet switch module according to claim 6, wherein the light shielding member is formed in a part along an outline of the lower surface protrusion.

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