JP2008130506A - Key base, key sheet provided with the same, and key unit provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a structure of a key base 8 and to make it easy to manufacture in an illuminated key sheet in which a plurality of key tops 6 are provided on a key base 8 or a key unit 2 using the same.
SOLUTION: The key base 8 is made of a transparent material and corresponds to the light guide film 14 that receives light from the light source 26 (LED) on the side and guides the light, and the key top 6 on the back surface of the light guide film 14. Reflective means (reflective layer) 16 that reflects light from the light source (LED) 26 formed at the position to the key top 6 formed on the top surface side of the light guide film 14, and the back surface of the reflective means (reflective layer) 16 And the presser 20 provided corresponding to the key top 6.
[Selection] Figure 4

Description

  The present invention relates to an electronic device, for example, a mobile phone, a PHS, a personal digital assistant (PDA, etc.), a portable audio, an illuminated key base such as a remote controller for home appliances, a key sheet provided therewith, and a key provided therewith Regarding the unit.

  For example, as a key sheet used in an electronic device such as a mobile phone, PHS, personal digital assistant (PDA, etc.), portable audio, remote controller for home appliances, a key top or the like is a predetermined illumination light source (for example, a light emitting diode). Many are illuminated. This is because there is an advantage that the key can be easily visually recognized even in a dark place and the operation becomes easy.

The applicant company of the present application has made various proposals regarding such an illuminated key sheet or a key unit in which such a key sheet is assembled to a wiring board or the like by, for example, Japanese Patent Application No. 2006-013232.
FIG. 8 is a sectional view showing a conventional example of a key unit in which such a narrow pitch type key sheet is arranged on a wiring board.
In the drawing, reference numeral 100 denotes a wiring board, a wiring film (not shown), a light source for illumination (for example, LED (Light Emitting Diode)) that does not appear in the drawing, and a metal dome (for example, stainless steel / SUS steel) in which switch contacts are arranged 102) on the surface.
104 is a reinforcing plate constituting the key base 107 with the keypads 106, 106,..., Which is made of a transparent resin such as polycarbonate or metal, for example, and has a plurality of keypad arrangement holes 104a in which the keypads 106 are arranged. , 104a,.

The keypads 106, 106,... Fit in the keypad arrangement holes 104a, 104a,... Of the reinforcing plate 104, and the keypad arrangement holes on the outer surface of the keypads 106, 106,. 104a, 104a,... Are fixed to the inner side surfaces thereof, and are reinforced by the reinforcing plate 104 so as to obtain the necessary mechanical strength as the key base 107.
Reference numeral 108 denotes a light-shielding mask sheet (: light-shielding plate) disposed on the key base (particularly when the reinforcing plate 104 is made of transparent resin), and between adjacent key tops (110 and 110) described later. It occupies the area corresponding to the lower side and shields light, and is made of a light-shielding film or a metal thin plate.

Reference numeral 110 denotes a key top, which is fixed to the upper surface of the base portion 106 a of the keypad 106. Reference numeral 106b denotes a pusher portion. The key top is generally made of a transparent resin such as polycarbonate, but from the viewpoint of design, aesthetics, etc., the key top may be made of metal or may have a surface plated with metal.
Japanese Patent Application No. 2006-0132232

  By the way, in the conventional key sheet as shown in FIG. 8, the key base 107 has the keypad arrangement holes 104a, 104a,... Of the reinforcing plate 104 having the keypad arrangement holes 104a, 104a,. The keypads 106, 106,... Are fixed to the inner peripheral surface.

  The key tops 110, 110,... Are illuminated using a number of LEDs arranged on the wiring board 100. The reinforcing plate 104 and the keypads 106, 106,... Have a function of guiding the light of the LED, but are not designed mainly for the function of guiding the light. 110 .... A large number of LEDs are required to illuminate everything with sufficient brightness. Mask light 108 is required due to extra light leakage from parts other than the key tops 110, 110,. As a result, the structure of the key base and the key sheet is complicated and the cost is increased.

  The present invention has been made to solve such a problem. In a key sheet having a plurality of key tops on a key base or a key unit using the key sheet, the structure of the key base is simplified and the manufacturing cost is reduced. The purpose of this is to make it easier to manufacture.

The key base of claim 1 is made of a transparent material and guides light from the light source, and is formed on the back surface of the light guide film so that the light from the light source is on the top side of the light guide film. It is characterized by comprising a reflecting means for reflecting to the formed key top and a pusher provided on the back surface of the reflecting means corresponding to the key top.
A key base according to a second aspect of the present invention is the key base according to the first aspect, wherein the reflecting means is selectively formed only in an area corresponding to the key top.

A key base according to a third aspect is the key base according to the first or second aspect, wherein the key base comprises a coating film printed on the back surface of the light guide film. A white ink is suitable as the coating film, and a normal white ink may be used as the ink, or a white ink containing a diffusing material may be used. In order to colorize the illumination light, it is preferable to perform white ink dot printing on the back surface of the light guide film and print a color coating film of a desired color on the dot-printed surface.
In that case, for example, a color ink containing a fluorescent pigment may be used as the color ink.
The key base according to claim 4 is the key base according to claim 1, 2 or 3, wherein one or two light sources are arranged corresponding to the position of the side surface of the light guide film, and the light guide film is disposed on the side surface. And receiving light from the light source and guiding the light.

  The key sheet according to claim 5 is a key sheet in which a plurality of key tops are provided on a key base, wherein the key base has the key top formed on a surface on the top surface side, and is made of a transparent material and is made of a light source. A light guide film that guides the light of the light, a reflection means that is formed on the back surface of the light guide film and reflects light from the light source to a key top formed on the top surface side of the light guide film, and the reflection means It is characterized by comprising a presser provided on the back surface corresponding to the key top.

  The key unit according to claim 6 includes a plurality of key tops, a light guide film in which the plurality of key tops are formed on the top surface, and light from a light source formed on the back surface of the light guide film. And a key sheet composed of a presser provided corresponding to the key top on the back surface of the reflecting means, and a switch corresponding to the presser on one surface. The circuit board includes a switch, a light source, and a switch connected to the light source, and a wiring board on which the key sheet is placed.

According to the key base of the first aspect, the illumination light from the light source is guided to the portion corresponding to the key top by the light guide film, and reflected to the key top side by the reflecting means formed on the back surface of the light guide film. You can make it.
The key base can be formed by providing a reflecting means on the back surface of the light guide film made of a patterned transparent material and forming a pusher on the back surface of the reflecting means, as in the prior art. The troublesome manufacturing of fixing the keypad to the inner peripheral surface of each keypad arrangement hole of the reinforcing plate having the keypad arrangement hole is eliminated.

According to the key base of the second aspect, since the reflecting means is provided only in the portion corresponding to each key top, the illumination light from the light source can be effectively irradiated only on the key top.
And where no reflection means is provided, the illumination light does not go out from the light guide film to the top surface side, so it becomes possible to eliminate the necessity of providing a mask sheet (: light-shielding plate) that was conventionally required, The structure of the key base and key sheet can be further simplified.

According to the key base of the third aspect, since the reflecting means is formed by the coating film formed on the back surface of the light guide film, it can be formed by a simple method of printing on the back surface of the light guide film.
According to the key base of the fourth aspect of the present invention, it is possible to receive the illumination light from one or two light sources arranged corresponding to the side surfaces of the light guide film and guide the light to the place having the reflecting means. The number of LEDs to be reduced can be reduced, and the cost can be reduced.

According to the key sheet of claim 5, since it has the key base of claim 1, it is possible to enjoy the effect of the invention according to claim 1.
According to the key sheet of the sixth aspect, since the key base of the first aspect is provided, the effect of the invention according to the first aspect can be enjoyed.

  In the embodiment of the present invention, basically, a key base is formed on a light guide film and illumination light which is formed on the back surface of the light guide film and progresses while repeating internal reflection to the key top side. The reflecting means is composed of a reflecting means and a pusher provided on the back side of the reflecting means corresponding to the key top, and the light guide film is naturally formed of a transparent material that transmits light. Although necessary, the most suitable is, for example, urethane resin or silicone.

The reflecting means can be composed of a coating film formed on the back surface of the light guide film. For example, the coating film is preferably white ink, and the ink is preferably normal white ink, but the white ink containing a diffusing material is suitable. May be used.
In order to colorize the illumination light, white ink (ordinary or diffusing material) may be dot-printed on the back surface of the light guide film, and then the desired color on the surface. It is preferable to form a color coating film. As a color ink used for forming a color coating film, an ink containing a fluorescent pigment may be used.
However, instead of using a coating film, it is also possible to provide unevenness on the back surface of the light guide film and use the unevenness as a reflecting means.
The pusher is preferably light guide film silicone or UV (Ultra Violet) curable resin.

  The key top of the key sheet using the key base may be a resin having translucency, and does not particularly require the conditions specific to the present invention. For example, PC (polycarbonate), PET (polyethylene) Terephthalate) and PMMA (polymethyl methacrylate: acrylic) are suitable.

  The reflective layer provided corresponding to each key top is formed by dot-printing ink containing a diffusing material on the back surface of the light guide film by a screen printing method. Moreover, you may make it form by carrying out color printing (for example, fluorescent pigment containing) in the appropriate part of the back surface of the light guide film including the printed dot part.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.
1 to 4 show a first embodiment (first embodiment) in which the present invention is applied to a key unit used in a mobile phone. FIG. 1 is an exploded perspective view of the whole embodiment, FIG. Is a perspective view, FIG. 3 is a perspective view showing the back surface of the key base, and FIG. 4 is a cross-sectional view showing the structure of the key base.
First, an outline of the entire key unit will be described with reference to FIGS. 1, 2, and 3.

A key unit 2 includes a top cover member 4, a plurality of key tops 6, 6,..., A key base 8, and a wiring board 10. The key tops 6, 6,... And the key base 8 constitute a key sheet 9.
The top cover member 4 is made of a hard transparent resin or an opaque resin, and the key tops 6, 6,... Are loosely fitted at positions corresponding to the key tops 6, 6,. Holes 12, 12,... Are formed.

  Each of the key tops 6, 6,... Is made of a translucent resin such as PC (polycarbonate), PET (polyethylene terephthalate), PMMA (polymethyl methacrylate: acrylic), for example, a top surface decoration type or a back surface Although a decoration type display is formed, detailed illustration and explanation of the display structure and the like are not related to the essence of the present invention, and therefore, this example (Example 1) will be omitted.

The key base 8 includes a light guide film 14 and a pusher forming layer 18 laminated on the back surface of the light base film 14 via a reflective layer 16 made of, for example, white ink.
Since white ink has a function of reflecting light, it is suitable as the reflective layer 16, and ordinary white ink is optimal, but white ink containing a diffusing material is also suitable.
Since white ink has a function of reflecting light, it is suitable as the reflective layer 16, and ordinary white ink is optimal, but white ink containing a diffusing material is also suitable.
When the illumination light is colorized, white ink (for example, ordinary white ink or white ink with a diffusing material) is printed on the back surface of the light guide film 14 and a desired color is printed thereon. good.

  The pusher forming layer 18 has a pusher 20, 20,... And spacers 22, 22,. The pushers 20, 20,... Transmit the pushed force to the metal dome (24) described later when the key tops 6, 6,. .. is to prevent the influence of one key top 6 from being exerted on the other adjacent key tops 6 when pressed, and only a part of the spacers 22, 22,. This is shown in FIG.

  The light guide film 14 constituting the key base 8 is formed of a light guide resin such as urethane or silicone. In addition, the pusher forming layer 18 in which the pushers 20, 20,... And the spacers 22, 22,.

  The surface of the wiring board 10 is provided with metal domes 24, 24,... And two LEDs (light emitting diodes) 26, 26 that form a light source. The number of LEDs 26 is not necessarily two, and may be one, for example, or three or more. However, in the present embodiment, it is preferable to increase the number of LEDs 26 to five, six, or more as in the conventional case, which prevents power consumption from being reduced and prevents the number of parts from being reduced. It is set to 2 because it is not recognized. Further, by using the above-described resin having high light guiding property such as urethane or silicone as the film 14, sufficient illumination for the key tops 6, 6,... Can be achieved even with a small number of LEDs 26, 26. It is.

The LEDs 26 and 26 are located outside the key base 8 when the key base 8 is bonded to the surface of the wiring board 10 as will be described later, and the light guide point of the key base 8 is a light emitting point. The position and the like are set so as to face the 14 side surfaces.
The metal domes 24, 24,... Have switches (not shown) that are turned on by being pushed by the pushers 20, 20,.
A film 28 is bonded to the surface of the wiring board 10, and the positions of the metal domes 24, 24,... Are fixed to the surface of the wiring board 10 by the film 28.

In this key unit 2, a top cover member 4 is assembled and bonded to a key base 8 having key tops 6, 6,. So that the light emitting points of the LEDs 26 and 26 face the light guide film 14 of the key base 8 so that the pressers 20, 20,... Correspond to the corresponding metal domes 24, 24,. It is configured by aligning and fixing with, for example, a double-sided tape.
The cross-sectional structure at that time is as shown in FIG. 4, the illustration of the film 28 for fixing the metal domes 24, 24,... To the surface of the wiring board 10 is omitted.

As is apparent from FIG. 4, the metal domes 24, 24,... On the surface of the wiring board 10 are respectively formed into the pushers 20, 20,. Each LED 26, 26 is located outside the key base 8, and its light emitting part faces the side surface of the light guide film 14 of the key base 8.
The back surface of the light guide film 14 of the key base 8 is made of, for example, white ink (normal white ink may be used, but white ink containing a diffusing material may be used) at a position corresponding to the key tops 6, 6. The reflective layer 16 is selectively formed by printing, for example.

And the keytops 6, 6,... Are formed on the surface of the light guide film 14 having the reflective layer 16 formed on the back surface, and the formation positions thereof are the pressers 20, 20,. It corresponds to the corresponding metal domes 24, 24,.
Therefore, when the LEDs 26 and 26 emit light, the light L travels in the plane direction of the film 14 while repeating internal reflection in the light guide film 14 and reaches the reflection layer 16. Then, it is reflected on the top surface side by this reflective layer 16, and illuminates the key tops 6, 6,.

According to the present embodiment, the illumination light from the LEDs 26, 26 forming the light source is guided to the portion corresponding to the key tops 6, 6,... By the light guide film 14 and formed on the back surface of the light guide film 14. The reflection layer 16 constituting the reflection means can be reflected toward the key top side.
The key base 8 is formed by providing the reflective layer 16 on the back surface of the light guide film 14 made of a patterned transparent material, and forming the pushers 20, 20,... On the back surface of the light guide film 14. It can be manufactured by laminating the pusher forming layer 18.

Therefore, the troublesome manufacturing of fixing the keypad to the inner peripheral surface of each keypad arrangement hole of the reinforcing plate having the keypad arrangement hole as in the prior art is eliminated.
Further, the light guide film 4 is used as a film constituting the key top 6 together with the pusher forming layer 18, and the light from the LEDs 26, 26 is guided to the key tops 8, 8,... Therefore, the attenuation of light that occurs before reaching the key tops 6, 6,.
Therefore, even if the number of LEDs 26 is two, for example, less than the conventional one, it is possible to illuminate with the necessary brightness.
Therefore, according to the present embodiment, the structure is simple, the number of LEDs 26 can be reduced, the number of parts can be reduced, and the power consumption can be reduced.

FIG. 5 is a cross-sectional view showing the main part of a second embodiment (embodiment 2) in which the present invention is applied to a key unit used in a mobile phone.
In the figure, 6 is a key top, 40 is a character print layer formed on the back surface of each key top 6, a light shielding film 42 selectively formed on the back surface of the key top 6 by screen printing, and the light shielding film 42. The coating film 44 is formed so as to cover the back surface of the key top 6 including the surface of the key top 6, and the key top 6 is displayed by a letter.

A light guide film 14 is made of urethane, for example, and is adhered to the back surface of the character print layer 40.
46 is a reflective layer, provided at a position corresponding to each of the key tops 6, 6,..., Dot-like reflective portions 48, 48,. The dot-shaped reflection parts 48, 48,... And the entire reflection part 50 formed so as to cover the back surface of the light guide film 14 including the top.

  The dot-shaped reflection portions 48, 48,... Are formed in a dot shape by screen printing of a diffusing material, and the planar shape is basically a circle. In this embodiment, the distance between the centers of each dot Is constant, and by changing the size of the dots, the ratio of the area of the dot-like reflecting portion 48 occupying a certain area is changed to vary the amount of light. Specifically, as the distance from the light source increases, the ratio of the area of the dot-like reflecting portion 48 that occupies a certain area is increased to compensate for the amount of light that attenuates due to repeated internal reflection.

Moreover, although the cross-sectional shape is a rectangle in the embodiment shown in FIG. 5, the cross-sectional shape may be a semicircular shape. If screen printing is performed so that the thickness of the ink at the center of the dot increases and decreases toward the periphery, it is easy to obtain a semicircular cross section.
The entire reflection portion 50 is formed by printing color ink (for example, color ink containing a fluorescent pigment).

Reference numeral 18 denotes a presser forming layer made of, for example, silicone rubber, and 20 denotes a presser formed integrally on the back surface of the presser forming layer 18.
FIG. 6 is a plan view showing how the reflective layer 46 shines in the second embodiment. Each chamfered rectangular portion in the black region is a portion corresponding to the key top 6, and there is a small size existing therein. A circle indicates a reflection part by the dot-like reflection part 48.
FIG. 7 is a plan view showing how light shines in use in the second embodiment.

  INDUSTRIAL APPLICABILITY The present invention can be applied to electronic devices such as a mobile phone, a PHS, a personal digital assistant (PDA, etc.), a portable audio, an illuminated key sheet for a remote controller for home appliances, and a key unit including the same. .

1 is an overall exploded perspective view of a first embodiment of the present invention. It is a perspective view of the said 1st Example. It is a perspective view which shows the back surface of the key base of the said 1st Example. It is sectional drawing of the key base of the said 1st Example. It is sectional drawing which shows the principal part of the 2nd Example of this invention. It is a top view which shows how to light the reflection layer in the said 2nd Example. It is a top view which shows how to shine at the time of use in the said 2nd Example. It is sectional drawing which shows a prior art example.

Explanation of symbols

2 ... key unit, 4 ... top cover member, 6 ... key top,
8 ... key base, 9 ... key sheet, 10 ... wiring board,
12 ... key loose fitting hole, 14 ... light guide film, 16 ... reflecting means (reflective layer),
18 ... presser forming layer, 20 ... pusher, 24 ... metal dome,
26... Light source (LED), 46... Reflecting means (reflection layer), 48.

Claims (6)

A light guide film made of a transparent material and guiding light from a light source;
Reflecting means for reflecting light from the light source formed on the back surface of the light guide film to a key top formed on the top surface side of the light guide film;
A pusher provided on the back surface of the reflecting means corresponding to the key top;
Key base characterized by consisting of The key base according to claim 1, wherein the reflecting means is selectively formed only in an area corresponding to the key top. The key base according to claim 1, wherein the reflecting means is formed of a coating film printed on a back surface of the light guide film. One or two light sources are arranged corresponding to the position of the side surface of the light guide film,
The key base according to claim 1, 2, or 3, wherein the light guide film receives and guides light from a light source on a side surface thereof. A key sheet provided with a plurality of key tops on a key base,
The key base has the key top formed on the surface on the top surface side, is made of a transparent material and guides light from the light source, and the light from the light source is formed on the back surface of the light guide film. A key sheet comprising: reflecting means for reflecting the light to a key top formed on the top surface side of the light guide film; and a pusher provided on the back surface of the reflecting means corresponding to the key top. Multiple key tops,
A light guide film in which the plurality of key tops are formed on the top surface, a reflection means formed on the back surface of the light guide film for reflecting light from the light source to the key top, and the key on the back surface of the reflection means. A key sheet consisting of a presser provided corresponding to the top;
A switch that is switched by the pusher at a position corresponding to the pusher on one surface, a light source and the switches, and a wiring board that has at least a wiring connected to the light source and on which the key sheet is placed;
A key unit characterized by comprising

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