JP4728067B2 - Seat switch module - Google Patents

Description

  The present invention relates to a sheet switch module having an illumination function mounted on an operation panel of various electronic devices.

  2. Description of the Related Art Conventionally, many operation panels mounted on various electronic devices such as a mobile phone and a portable information terminal are configured using a key switch incorporating a lighting function. As such an illumination function, light emission (minimum light emission) can be minimized by individually arranging light sources (light emitting elements) corresponding to the individual pressing portions (key tops) constituting the key switch or using a light guide plate. A configuration is adopted in which each key top is efficiently illuminated with an element (Patent Document 1). FIG. 8 shows a configuration example of the key switch 1 using the light guide plate. The key switch 1 includes a circuit board 2 on which a fixed contact 3 and a wiring pattern are formed, a movable contact 4 including a tact spring disposed on the fixed contact 3, and a light guide plate 5 disposed on the circuit board 2. And a light emitting element 6 that irradiates the side surface of the light guide plate 5 and a key top 7 that penetrates the light guide plate 5 and presses the movable contact 4. In the key switch 1, the entire key top 7 is illuminated by irradiating the lower end portion of the key top 7 penetrating the light guide plate 5 with light guided from the light emitting element 6.

In addition, a key switch (Patent Document 2) that has an illumination function and is further thinned in order to cope with the thinning of electronic devices in recent years is also known. FIG. 9 shows a cross-sectional structure of the key switch 11 described in Patent Document 2. The key switch 11 includes a circuit board 12 on which a fixed contact 13 is formed, a sheet switch unit 18 including a movable contact 14 disposed on the fixed contact 13, and a light guide plate 15 that covers the sheet switch unit 18. The light guide plate 15 is formed to have a key top 17 located at an upper portion where the movable contact 14 is formed. In the key switch 11, the light emitted from the light emitting element 16 disposed at one end of the circuit board 12 is irradiated on the side surface of the light guide plate 15, thereby causing the entire light guide plate 15 to emit light, and the key top. 17 is illuminated from the lower surface side.
JP 2004-69751 A (FIG. 9) JP 2004-69751 A (FIG. 6)

  In a key switch having a structure in which light emitting elements are individually arranged in the vicinity of individual key tops as described above, the number of light emitting elements must be increased as the number of key tops increases. There is a problem that the key switch itself increases in size as the power increases. Further, in the key switch 1 shown in FIG. 8, since the light is guided toward the key top by the light guide plate 5, the number of the light emitting elements 6 may be small, but the light emitted from the light emitting elements 6 is sufficient. In order to efficiently guide the light from the side surface without leakage, the light guide plate 5 must be formed with a thickness greater than a certain value. However, if the light guide plate 5 is made thicker, the thickness of the entire key switch 1 increases accordingly, and there is a problem that the thickness cannot be reduced.

  On the other hand, since the key switch 11 shown in FIG. 9 has a structure in which light emitted from the light emitting element 16 is incident on one end of the light guide plate 15 and guided to the whole, it is separated from the light emitting element 16. There is a problem that the brightness of the key tops 17 at the locations is lowered and the variation in brightness is conspicuous. In addition, since the light guide plate 15 is simply placed on the sheet switch unit 18, a gap is easily generated between the light guide plate 15 and the sheet switch unit 18. A gap is likely to be formed between the light emitting element 16 and the light emitting element 16 disposed at the end of the. If such a gap exists in the periphery of the light guide plate 15, light emission leaks from the gap, and there is a problem in that the amount of light transmitted to the key top 17 is insufficient and luminance variation occurs. For this reason, an illumination effect such that only the key top 17 emits light intensively cannot be obtained.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a key switch and an illumination function capable of guiding light emitted from a light emitting element toward a pressing portion efficiently without leaking and displaying the pressing portion with high brightness without variation. Is to provide a sheet switch module integrated with the above.

In order to solve the above problems, a seat switch module according to the present invention includes a circuit board on which a plurality of fixed contacts are arranged, a side-emitting light emitting diode arranged on the circuit board, and above each of the fixed contacts. A tact spring formed of a dome-shaped metal material disposed so as to be covered ; and a sheet material that covers and holds the tact spring on the circuit board; and by pressing the upper surface of the tact spring from above the sheet material a seat switch modules forming a switching circuit electrically connected to the fixed contact, the sheet material is embossed portion is provided comprising a shape corresponding to the shape of the corresponding and respective Takutobane in place covering holds the Takutobane In addition, a rising portion is formed on the outer peripheral portion of the embossed portion so as to follow the outer shape of the tact spring. It characterized in that it consists of a light guiding sheet for guiding light emitted from the light emitting diode along the rising portion on the upper surface of the Takutobane.

In the sheet switch module of the present invention, since the light guide sheet is covered along the upper surface of a tact spring formed of a dome-shaped metal material that is a pressing portion for switch operation, the light is emitted from a side-emitting light emitting diode. The light can be emitted and displayed with high brightness upward while being guided along the upper surface of the tact spring . This facilitates key input operation in a dark place, and even when the key top is arranged, characters, symbols, etc. formed on the surface by printing or the like can be displayed with high visibility.

  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, a sheet switch module (hereinafter simply referred to as a sheet switch) 21 according to the present invention includes a flexible circuit board (FPC) on which fixed contacts 22 and electrode patterns 23 and other connectors (not shown) are formed. 24, a movable contact 25 disposed on the fixed contact 22, a light guide sheet 26 which is in close contact with the upper surface of the movable contact 25 and covers the entire FPC 24, and one end of the light guide sheet 26. And the light emitting element 27.

  For example, when the FPC 24 is formed as a seat switch of an operation panel of a cellular phone, the FPC 24 is formed to have substantially the same shape and size as the operation panel, and numeric keys, alphabet keys, other function keys, and the like are arranged. A plurality of the fixed contacts 22 are provided according to the location. The movable contact 25 is formed of a dome-shaped tact spring made of a thin metal material in order to obtain an appropriate click feeling, and is disposed so as to cover the fixed contact 22 above. In addition, the upper surface of the movable contact 25 is, for example, mirror-finished to increase the reflectivity, and efficiently reflects light guided by the light guide sheet 26 from the light emitting element 27 mounted on the FPC 24. To do.

  The light guide sheet 26 is made of a transparent or translucent thin sheet material formed in substantially the same shape and size as the FPC 24. For example, a light guide sheet such as acrylic resin, silicon resin, polycarbonate resin, or polyethylene terephthalate resin is used. It is preferable to form with a high material. The thickness of the light guide sheet 26 is not particularly limited, but is in the range of 0.05 mm to 0.3 mm, particularly around 0.1 mm, in consideration of light guide efficiency and adhesion to the movable contact 25. Is preferably formed. As shown in FIGS. 1 to 3, it is preferable that an embossed portion 29 is formed in advance on the light guide sheet 26 at a location where the movable contact 25 is covered and held. The embossed portion 29 is formed corresponding to the outer shape of the movable contact 25, and a rising portion 32 is formed around the entire periphery thereof. As will be described later, the rising portion 32 is for making it easy for the light guided to the inside of the light guide sheet 26 to change the path of the light in the vicinity of the movable contact 25, and thereby the movable contact 25. Light is easily scattered on the top surface. When the sheet switch 21 is actually assembled, a transparent adhesive 28 is uniformly applied to the entire back surface of the light guide sheet 26 including the embossed portion 29, and the movable contact 25 is adhered and held on the adhesive surface of the embossed portion 29. This is aligned with the upper surface of the FPC 24 on which the fixed contact 22 is formed, and then brought into close contact with the upper surface of the FPC 24. The light guide sheet 26 is not provided with the embossed portion 29 as described above in advance, and the movable contact 25 is directly adhered to the light guide sheet 26 by a means such as heating and pressurization while the sheet is planar. It is also possible to carry out close-fitting molding along the outer shape, and in this case, the rising portion 32 as described above is formed at the boundary with the movable contact 25.

  When the light guide sheet 26 is coated on the upper surface of the FPC 24, as shown in FIG. 4, the embossed portion 29 can be directly covered and held on the movable contact 25 without applying the adhesive 28. . In this way, by directly adhering the light guide sheet 26 to the upper surface of the movable contact 25 without the adhesive 28, light absorption and attenuation by the adhesive 28 can be suppressed, and further upward. A high reflection effect can be obtained.

  In the example shown in FIG. 1, a side-emitting light emitting diode is used as the light emitting element 27. As shown in FIG. 1 and FIG. 2, the light emitting surface 27 a of the light emitting element 27 is disposed on the outer peripheral portion of the FPC 24 with the light emitting surface 27 a facing the outer peripheral side surface 33 of the light guide sheet 26. The arrangement location and the number of arrangement are appropriately set according to the shape and size of the FPC 24 and the number of arrangements of the fixed contact 22 and the movable contact 25. For example, numeric keys or function keys such as a mobile phone are arranged. In this case, several square sheet switches are arranged at equal intervals on each side. In addition, in order to make light emitted from the light emitting surface 27a of the light emitting element 27 efficiently enter the outer peripheral side surface 33 of the light guiding sheet 26 without leakage, the end of the light guiding sheet 26 emits light from the light emitting element 27. It is good to provide the incident part 34 formed thickly according to the height of the surface 27a. Further, the light emitted from the light emitting surface 27 a is filled by filling the gap between the light emitting surface 27 a of the light emitting element 27 and the outer peripheral side surface 33 of the incident portion 34 of the light guide sheet 26 with the transparent resin 31. Can be guided to the incident portion 34 of the light guide sheet 26 without leakage. The transparent resin 31 is preferably made of the same resin material as that of the light guide sheet 26, and is not particularly limited to a shape that closes the gap. The light emitting element 27 is not only arranged on the outer peripheral portion of the FPC 24 as described above, but may be arranged around each movable contact 25, and in that case, it is necessary to uniformly irradiate the periphery. From top to bottom light emitting elements are used.

  Next, based on FIG. 5, the illumination action of the sheet switch 21 configured as described above will be described. A current is supplied to the light emitting element 27 from a motherboard or the like via a connector (not shown) provided in the FPC 24. The light emitted from the light emitting surface 27 a of the light emitting element 27 is incident from an incident portion 34 formed on the outer peripheral side surface 33 of the light guide sheet 26 through the transparent resin 31. The incident light is guided through the light guide sheet 26 in parallel with the FPC 24 surface. Then, the light that has reached the rising portion 32 of the embossed portion 29 is reflected by the rising portion 32 and the path is suddenly changed, so that the light is repeatedly reflected in the light guide sheet 26 along the upper surface of the movable contact 25. Light is guided. Further, since the movable contact 25 is formed of a metal spring, the reflection efficiency on the entire upper surface of the movable contact 25 is large, and the reflected light is reflected radially as scattered light toward the upper side of the movable contact 25. Thus, since the light guide sheet 26 is formed in close contact with the outer shape of the movable contact 25 without a gap, the light emitted from the light emitting element 27 can be used as a pressing portion for key operation of the movable contact 25. The upper part can be illuminated with high brightness and no variation.

  Further, as described above, the upper surface of the movable contact 25 to which the light guide sheet 26 is in close contact is mirror-finished to provide a mirror-surface portion on the entire upper surface, or a concavo-convex portion having a fine concavo-convex process or a textured process is applied Accordingly, it is possible to improve the reflectance and the luminance by the light scattering effect. The movable contact 25 is not limited to being formed of a metal material. For example, a resin plate having elasticity is embossed like a tact spring and formed into a dome shape, and is electrically connected to the fixed contact 22 on the back surface. The movable contact electrode can be formed by forming a reflective metal film on the surface by plating or vapor deposition, 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 that of a metal tact spring as described above.

  Further, as a means for effectively guiding the light taken into the light guide sheet 26 toward the upper side of the movable contact 25, a light reflecting member or a light scattering portion is formed on the back surface or the surface of the light guide sheet 26. There is a way to do it. For example, by applying a light reflecting member made of a white or silver paint on the back surface of the light guide sheet 26, the light guided into the light guide sheet 26 is movable without being absorbed by the FPC 24. The contact point 25 can be irradiated intensively. Further, by forming a light scattering portion having a large number of irregularities on the upper surface of the light guide sheet 26, the light guided into the light guide sheet 26 is emitted toward the pressing portion while being diffused. be able to. Such a light scattering portion can be easily formed by subjecting a molding die used for manufacturing the light guide sheet 26 to a texture.

  The sheet switch 21 of the above embodiment can be used as it is as a pressing portion by printing characters, symbols, and the like representing various switch operations on the light guide sheet 26 covering the movable contact 25. By applying a light-shielding paint to the surface of the light guide sheet 26 other than the portion corresponding to the movable contact, or by covering with a thin light shielding member, the upper portion of the movable contact 25 is illuminated particularly brightly. Can be.

  FIG. 6 shows a sheet switch 51 having a configuration in which the light emitting element 52 is arranged at an end portion of the light guide sheet 56 and is appropriately arranged at a predetermined location other than the end portion to increase the light amount. It is. In the sheet switch 51 of this embodiment, a recess for storing the light emitting elements 52 and 53 mounted on the FPC 24 is provided. The recess is formed by a notch 54 provided at the end of the light guide sheet 56 and a hole 55 provided at a place other than the end. The light emitting element 52 disposed in the notch 54 is a side light emitting type light emitting diode, and the light emitting element 53 disposed in the hole 55 is a top light emitting type in order to emit light uniformly in all directions. A light emitting diode is used. Further, by filling the inner peripheral surfaces of the notches 54 and the holes 55 with the transparent resin 31, gaps between the light emitting elements 52 and 53 can be filled and radiation efficiency into the light guide sheet 56 can be improved. it can. Furthermore, by providing the incident portion 34 that is inclined according to the height of the light emitting elements 52 and 53, the light emitted from the light emitting elements 52 and 53 can be guided into the light guide sheet 56 without leaking. . Other structures such as the fixed contact 22, the movable contact 25, and the embossed portion 29 are the same as those of the sheet switch 21, and thus the description thereof is omitted.

  FIG. 7 shows a configuration example of the operation panel 41 in which the sheet switch 21 is incorporated. The operation panel 41 has the sheet switch 21 joined to an apparatus substrate 46 such as a mother board via a double-sided adhesive tape 42, and has a translucent rubber sheet 43 and a translucent upper portion. The key top 44 includes a plurality of top sheets 45 provided at predetermined locations.

  The rubber sheet 43 is formed to be approximately the same size as the FPC 24, and at least a portion corresponding to the key top 44 is formed to be transparent or translucent. Further, the pressing portion corresponding to the movable contact 25 is formed with a slight thickness. The rubber sheet 43 is disposed in parallel with the sheet switch 21 so that the pressing portion is in contact with the upper end of the movable contact 25. In order to stably dispose the rubber sheet 43 on the sheet switch 21, the height may be adjusted with a spacer (not shown) interposed therebetween.

  The surface sheet 45 constitutes a display surface of an operation panel of an electronic device on which the sheet switch 21 is mounted, and is generally formed of a soft resin material such as rubber and corresponds to the movable contact 25. Is a thick key top 44. The top sheet 45 is arranged so as to cover the upper side of the rubber sheet 43. Further, the key top 44 is formed to have translucency, and various characters, symbols, and the like are printed or unevenly formed on the surface thereof. The portion excluding the key top 44 is formed of a light shielding member that does not transmit light. Moreover, the light guide action in the light guide sheet 26 can be enhanced by forming a metal film on the back side of the light shielding member.

  The light emitted from the light emitting element 27 of the sheet switch 21 is guided toward every corner in the light guide sheet 26. The light guided onto the movable contact 25 is reflected upward by the metal surface of the movable contact 25. The light reflected on the movable contact 25 passes through the rubber sheet 43 and enters the key top 44, and the upper surface (operation surface) of the key top 44 can be illuminated brightly. As described above, since the light guide sheet 26 is in close contact with the surface of the tact spring that is curved in a dome shape, the light guided onto the tact spring does not leak to the surroundings, and most of the light. Can be reflected toward the key top 44 and can be illuminated with high brightness.

  The sheet switch 21 of the present invention is formed based on the FPC 24, can be bent, and the light guide sheet 26 is provided in close contact with the FPC 24. Therefore, the sheet switch 21 has a planar shape as shown in the above embodiment. It can be mounted not only on the operation panel but also on an operation panel formed in a curved surface shape in accordance with the shape of an electronic device or the like.

It is sectional drawing of the sheet switch module concerning this invention. It is a see-through | perspective perspective view of the said sheet switch module. It is explanatory drawing which shows the assembly example of the said sheet switch module. It is sectional drawing of the sheet | seat switch module which adhered the light guide sheet | seat to the movable contact, without using an adhesive. It is explanatory drawing which shows the light emission effect | action in a light guide sheet. It is a see-through | perspective perspective view of the sheet switch by the other example of arrangement | positioning of a light emitting element. It is sectional drawing which shows an example of the operation panel incorporating the said sheet switch module. It is sectional drawing of the conventional illumination type key switch. It is sectional drawing of the illumination type key switch by the other conventional structural example.

Explanation of symbols

21 Sheet switch 22 Fixed contact 23 Electrode pattern 24 FPC
DESCRIPTION OF SYMBOLS 25 Movable contact 26 Light guide sheet 27 Light emitting element 28 Adhesive 29 Embossed part 31 Transparent resin 32 Standing part 33 Outer side surface 34 Incident part 41 Operation panel 42 Double-sided adhesive tape 43 Rubber sheet 44 Key top 45 Surface sheet 46 Device substrate

Claims (9)

A circuit board on which a plurality of fixed contacts are arranged;
A side-emitting LED disposed on the circuit board;
And Takutobane formed of a metal material of a dome type, which is arranged so as to cover above the fixed contacts,
A sheet material for covering and holding the tact spring on the circuit board;
A sheet switch module that forms a switching circuit by conducting to the fixed contact by pressing the upper surface of the tact spring from above the sheet material,
It said sheet material, with embossed portions made of shape corresponding to the shape of the corresponding and respective Takutobane in place covering holds the Takutobane is provided, on the outer periphery of the embossed portions, such as along the outer shape of Takutobane A sheet switch module comprising a light guide sheet that has a rising portion and guides light emitted from the light emitting diode along the upper surface of a tact spring from the rising portion . The light guiding sheet is coated with an adhesive on the upper surface of the Takutobane or sheet switch module according to claim 1 wherein the coated so as to be in close contact directly without an adhesive to the upper surface of Takutobane. The seat switch module according to claim 1, wherein the rising portion is formed around an embossed portion formed corresponding to an outer shape of the tact spring . The light guiding sheet, the sheet switch module according to claim 1 or 2 is formed 0.05mm~0.3mm thickness of the acrylic resin, silicone resin, polycarbonate resin, by any of a polyethylene terephthalate resin. The sheet switch module according to claim 1, wherein a gap formed between an end portion of the light guide sheet and the light emitting diode disposed in the vicinity of the end portion is closed with a transparent resin. Wherein the light guiding sheet is provided a recess for accommodating a light emitting diode, sheet switch module according to claim 1, wherein closing the gap generated between the inner peripheral surface of the light emitting diode and a recess housed in the recess in the transparent resin.
The sheet switch module according to claim 6 , wherein the concave portion is a notch formed at an end portion of the light guide sheet or a hole portion opened at a place other than the end portion. Sheet switch module according to claim 1, wherein the mirror unit for the light reflected on the upper surface of the Takutobane is formed. Sheet switch module according to claim 1, wherein an uneven portion for light scattering is formed on the upper surface of the Takutobane.

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