JP2009187832A - Decorative layer and key unit equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain specific effects giving out different colors according to watching angles in correspondence to diversification of demands on decorative layers and decoration with outside light of key units using the decorative layers, facilitate extraction of colors or selection of wavelengths of reflecting light, make adjustment of illumination luminance, and further, obtain any reflective characteristics. <P>SOLUTION: The decorative layer 2 is structured by laminating one or a plurality of dielectric layer laminates on a light-transmitting base 4 laminating a plurality of dielectric layers 6a, 6b, 8a, 8b so that at least any adjacent ones have different refractive indices. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a decorative layer used for a key unit of an electronic device, for example, a mobile phone, a PHS, a personal digital assistant (PDA, etc.), a portable audio, a remote controller for home appliances, and a key unit including the decorative layer.

  For example, key units used in electronic devices such as cellular phones, PHS, personal digital assistants (PDAs, etc.), portable audio devices, remote controllers for home appliances, etc. generally have numbers and other characters on the lower surface (back surface) or upper surface (front surface). A plurality of key tops provided with a display of symbols, patterns, etc. and coloring of other parts (hereinafter referred to as “decoration”), and at least one pusher corresponding to each switching element on the back surface. The key base is formed on the surface of the key base, and the key base is disposed on the surface of the wiring board on which the metal dome and the wiring film in which the switching element that is turned on by being pushed by the pusher is built.

The key unit is of a type using a light emitting diode (LED) provided on a wiring board as a light source for illuminating the display on the key top (Japanese Patent Application No. 2006-060095: Patent Document 1) or one of the key bases. There is a type using an EL (electroluminescence) sheet formed so as to form a part (Japanese Patent Application No. 2005-359420: Patent Document 2).
In any case, for the key display, an illumination light source is provided, and illumination light generated from the light source is used.

By the way, in the conventional key unit, a metal thin film is formed on the whole or a part of the surface of the key top, and external light is reflected on the surface of the key top, so that the decorativeness when not illuminated is further improved. A half mirror was formed (Japanese Patent Laid-Open No. 11-027362: Patent Document 3).
FIG. 7 is a sectional view showing a half mirror part of such a key unit.
In the figure, a is a transparent base film made of, for example, a resin, b is a metal thin film formed on the surface thereof by, for example, vacuum deposition, etc., and a half mirror c is constituted by the base film a and the metal thin film b. The

When external light is incident on the surface of the half mirror c, a part of the incident light is reflected on the surface of the metal thin film b in the entire wavelength region, and another part of the incident light is formed between the metal thin film b and the base film a. Reflected at the boundary surface, the remaining incident light passes through the base film a.
During illumination, illumination light from an illumination light source (not shown) enters the half mirror c from the back surface, and part of the light is reflected and the rest is transmitted. As described above, in the case of the half mirror c, the reflected light and the transmitted light have almost no wavelength dependence, and reflection or transmission occurs at a constant rate over the entire wavelength. FIG. 8 is a relationship diagram showing the transmittance [% T] of each wavelength [nm] of the half mirror c.

Such a conventional decorative layer has the characteristics that the transmittance can be arbitrarily controlled by the film thickness, the wavelength dependency is small, and the reflected light has a metal color (silver color).
Japanese Patent Application No. 2006-060095 Japanese Patent Application No. 2005-359420 Japanese Patent Laid-Open No. 11-027362

By the way, there is an increasing demand for diversification of design and decoration for a mobile phone, a personal digital assistant (PDA, etc.), a portable audio player and the like using a key unit, and the manufacturer has not been able to meet the demand.
This is because the conventional half mirror c in which the metal thin film b is laminated on the surface of the base film a has a problem that it is difficult to extract colors, that is, to select the wavelength of light to be reflected. It is difficult to meet the diverse demands of consumers.

Of course, there are not a few people who prefer metal color as the color of mobile phones, etc., and the conventional half mirror c is suitable for consumers with such a tendency, but there are many people who do not like metal color, The conventional half mirror c cannot meet the demand of such people.
Further, the conventional half mirror c has a problem in that as the metal thin film b is thicker, the amount of reflected light increases and the illumination becomes darker.
This is because the metal thin film b has a particularly low light transmittance in the human visible light region, and it is difficult to obtain a light amount.

On the other hand, the thinner the metal thin film b, the smaller the amount of reflected light, the less the metal feeling, and the lesser the feature that it becomes a metal color.
That is, there is a problem in the conventional half mirror c that there is a trade-off between illumination and metal feeling (amount of reflected light) that one becomes better and the other becomes worse.

  The present invention has been made to solve such a problem, responding to the diversification of demand for decoration by the external light of the key unit using the decorative layer and the decorative layer, and depending on the viewing angle. A unique effect of different colors is obtained, color extraction, that is, selection of the wavelength of reflected light, facilitating adjustment of illumination brightness, and reflection of light in an arbitrary wavelength range The purpose is to make it easier to obtain properties.

The decorative layer according to claim 1 is obtained by laminating one or a plurality of dielectric layer laminates obtained by laminating a plurality of dielectric layers so that at least the ones in contact with each other have different refractive indexes on a light-transmitting base. It is characterized by.
The key unit according to claim 2 is a dielectric in which a plurality of dielectric layers are laminated so that at least the ones in contact with each other have different reflectances, and incident light from the front side is reflected at the interface of the dielectric layers. A decorative layer obtained by laminating one or more layered laminates on a light-transmitting base, display means for selectively displaying light to indicate a key, and transmission through the display means And an illumination light source that generates light for displaying a key.

  The key unit according to claim 3 includes a plurality of key tops each having a light shielding film selectively formed on the upper surface or the rear surface for display, a key base positioned below the key tops, and the key bases. A dielectric that has at least an illumination light source that irradiates the key top, and is laminated on at least the upper surface or the back surface of each key top so that the refractive indexes of at least a plurality of dielectric layers in contact with each other are different from each other A decorative layer is formed by laminating one or a plurality of layer laminates on a light-transmitting base.

  According to the present invention, a dielectric layer laminate in which a decorative layer is laminated such that a plurality of dielectric layers at least in contact with each other have different refractive indexes is formed on a light-transmitting base film or key top. Since one or more layers are laminated, the reflected light generated at the interface between the air and the dielectric layer, the interface between the dielectric layer and another dielectric layer having a different refractive index, and the interface between the dielectric layer and the base film Since the wavelength characteristics of reflected light change due to interference (mixing), it is possible to obtain a variety of brightly colored reflected light, which means more diverse decorative colors than half mirrors that can only obtain metal colors Can respond to requests.

Various reflection characteristics can be obtained by changing the setting of the number of stacked dielectric layers and the thickness of each dielectric layer (for example, 100 to 500 angstroms). This is because the wavelength of reflected light varies depending on the thickness of the dielectric layer.
Further, it is possible to obtain a unique decorative effect that the color changes by changing the viewing angle with respect to the decorative layer. This is because there is an incident angle dependency of the wavelength of the reflected light.
The color changes when the visual perception of the surface of the decorative layer changes from a substantially vertical angle to an oblique angle. When the angle changes, the distance of light passing through the dielectric layer changes, and the layer changes depending on the angle of incident light. This is thought to be because the length of passage is different.

In the present invention, basically, one or a plurality of dielectric layer laminates in which a plurality of dielectric layers are laminated so that the refractive indexes of those at least in contact with each other are laminated on a light-transmitting base. The number of dielectric layer stacks is specifically 2 to several tens.
The dielectric film can be formed of, for example, titanium oxide, niobium oxide, or silicon oxide film (SiO 2), and as a dielectric layer laminated on each other, titanium oxide having a high refractive index and silicon oxide film having a low refractive index are selected. Is the best. And it can be said that it is preferable to form it, for example, amorphous by vacuum deposition, sputtering or the like.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.
FIG. 1 is a cross-sectional view showing one embodiment 2 of the decorative layer of the present invention.
In the figure, 2 is a decorative layer, 4 is a film base having transparency, and 6a is a dielectric layer laminated on the film base 4 and has a certain refractive index.
8a is another dielectric layer laminated on the dielectric layer 6a, and has a refractive index different from that of the dielectric layer 6a.

Reference numeral 6b denotes a dielectric layer made of the same material as the dielectric layer 6a, and is laminated on the dielectric layer 8a. A dielectric layer 8b is laminated on the dielectric layer 6b and is made of the same material as the dielectric layer 8a.
As described above, the decorative layer 2 of the present invention is obtained by laminating a dielectric layer laminated body in which a plurality of dielectric layers are laminated so that at least the layers in contact with each other have different refractive indexes on a base 4 having light transmittance. In this embodiment, the number of laminated dielectric layers is 2, but it may be 1 or may be larger than 2.

According to such a decorative layer 2, the interface between air and the dielectric layer 8b, the dielectric layer 8b (or 6b, 8a) and another dielectric layer 6b (8a, 6a) laminated on the dielectric layer 8b having different refractive indexes. ), And at the interface between the dielectric layer 6a and the base film 4, the reflected light is visually recognized as decorative light of a predetermined color.
And since the light transmission characteristics change due to the interference of the reflected light generated at different interfaces, it is possible to obtain a variety of brightly colored reflected light, which is more of a decorative color type than a half mirror that can only obtain a metal color It can meet the demand for diversification.

Various reflection characteristics can be obtained by changing the setting of the number of stacked dielectric layers and the thickness of each dielectric layer (for example, 100 to 500 angstroms). This is because the wavelength λ of the reflected light changes depending on the thickness of the dielectric layers 6 and 8.
Moreover, the characteristic decoration effect that a color changes by changing the viewing angle with respect to the decoration layer 2 can also be acquired. There is an incident angle dependency of the wavelength of the reflected light.
The color changes when the viewing angle with respect to the surface of the decorative layer 2 is changed from a substantially vertical angle to an oblique angle, because the distance of light passing through the dielectric layers 6 and 8 is different when the angle is different. It is done.

FIG. 2 is a cross-sectional view showing a key unit 10 using the decorative layer 2 shown in FIG. 1. This key unit 10 is used in, for example, a mobile phone, and is provided with a display screen such as a liquid crystal display (LCD). This covers the entire front surface (upper surface) of the mobile phone including the portion that is provided.
20, 20,... Are light-shielding films selectively formed on the back surface of the decorative layer 2 (the back surface of the base film 4 having transparency). To block the light.
22, 22,... Are portions where the light-shielding film 20 is not formed on the back surface of the base film 4, that is, portions where the light-shielding film 20 is missing in the shape of characters, symbols, and the like. Each key is displayed when light from) passes through. There are two types of display, one based on the shape of a portion through which light passes (positive type) and the other based on the shape of a portion where light is blocked (negative type).

Reference numeral 26 denotes a protective layer formed so as to cover the back surface of the base film 4 including the back surface of the light shielding film 20, and is formed of a coating film having colored or colorless transparency (light transmittance).
Reference numeral 28 denotes a key base adhered to the back surface of the protective layer 26 in a portion to which the function of the operation key other than the portion covering the front surface and the periphery of the display screen of the key unit 10 is assigned, and elastic such as silicone rubber and various elastomers. It is made of various soft or hard transparent resins including materials, and pressers 30, 30,... At positions corresponding to the keys are formed on the back surface, and key sheet support portions that do not appear in the drawings.

32 is a wiring board on which a wiring film (not shown) is formed and light emitting diodes 34, 34,... Constituting illumination light sources are mounted, and further, the pushers 30, 30,. ... Are arranged at the portions corresponding to the metal domes 36, 36,... With built-in switches (not shown) that are pushed by the pushers 30, 30,.
On the wiring board 32, the key base 28 is supported by a key sheet support portion that does not appear in the drawings, and the pressers 30, 30,... Corresponding to the keys and the metal domes 36, 36. ,... Are positioned and fixed so as to be aligned with each other.

When the key unit 10 is not illuminated (not in use), the light-emitting diodes 34, 34,... Are not lit, and the light incident on the decorative layer 2 is reflected as described above. ) Shines in the color of the reflected light. This color changes depending on the viewing angle, that is, depends on the angle dependency of the wavelength (color) of the reflected light.
In use, the backlight of the display screen and the light emitting diodes 34, 34,... Are turned on, and the generated light proceeds upward as illumination light, and the light shielding film 20 on the back surface of the base film 4 in the display screen portion. Are passed through the decorative layer 2 and are incident on the key base 28 at the operation key portion, and further, the back surface of the base film 4 is shielded from light. .. Pass through the portions 22, 22,... Where the film 20 is not formed, and further passes through the decorative layer 2, and as shown in FIG. Make it appear.

Therefore, when the user recognizes a key from the display and presses an arbitrary key based on the recognition, the metal dome 36 is pushed by the pusher 30 corresponding to the key, and a switch (not shown) in the inside is turned on.
The decorative layer 2 according to the present invention has a surface reflected light depending on the material of each dielectric layer 6a, 6b,..., 8a, 8b,. Can be changed.
Therefore, for example, the decorative layer 2 of different colors such as purple, white, and yellow can be provided.
By the way, FIG. 4 shows three kinds of decorative layers 2 with different colors of reflected light (purple, white, yellow) and colors with a relatively vertical viewing angle with respect to each wavelength [nm]. It is a related figure which shows the transmittance | permeability [% T] of the decoration layer 2. FIG.

5 (A) and 5 (B) show an embodiment in which the present invention is applied to a key unit in which each key top is independent, (A) is an exploded perspective view, and (B) is one key top. It is sectional drawing shown.
First, an outline of the key unit 52 will be described with reference to (A). The key unit 52 includes a top cover member 54, a plurality of key tops 56, 56,..., A key base 58, and a wiring board 60. The key tops 56, 56,... And the key base 58 constitute a key sheet 59.
The top cover member 54 is made of a film-like hard transparent resin, for example, PC (polycarbonate), PET (polyethylene terephthalate), PMMA (polymethyl methacrylate: acrylic), and the upper surface thereof has the same decoration as a key top described later. A film and a light-shielding film are formed, and key loose holes 62, 62,... In which the key tops 56, 56,. -Is formed.

Each of the key tops 56, 56,... Is made of a translucent resin, for example, PC (polycarbonate), PET (polyethylene terephthalate), PMMA (polymethyl methacrylate: acrylic), for example, a top surface decoration type or a back surface. Although a decorative type display is formed, detailed illustration and description of the display structure and the like are not related to the essence of the present invention, and thus the description of this embodiment is omitted.
The key base 58 is formed with a pusher forming layer on the back surface of the light guide film, and the pusher forming layer has a pusher and a spacer integrally formed on the back surface. When the key tops 56, 56,... Are pushed, the pusher transmits the pushed force to the metal domes 74, 74,.

The light guide film constituting the key base 58 is formed of a light guide resin such as urethane or silicone. Moreover, the pusher forming layer on the back is made of, for example, silicone or UV curable resin.
The wiring board 60 is provided with metal domes 74, 74,... And LEDs (light emitting diodes) 76, 76 forming a light source on the surface. The metal domes 74, 74,... Have a switch (not shown) that is turned on by being pushed by the pusher inside.

A film 78 is bonded to the surface of the wiring board 60, and the positions of the metal domes 74, 74,... Are fixed to the surface of the wiring board 60 by the film 78.
The key unit 52 includes a key base 58 having a key top 56, 56,... Bonded to the surface, and a top cover member 54. The key free insertion holes 62, 62,. Are aligned and bonded together to form a laminated body, and this laminated body is arranged on the wiring board 60 so that the pusher of the key base 58 corresponds to the metal domes 74, 74,. It is comprised by aligning and assembling.

  In use, the LEDs 76 and 76 constituting the light source are turned on, and the light passes through the light guide film constituting the key base 58 and passes through the key tops 56, 56,. It becomes the illumination light of the display and realizes a clear display.

Next, the cross-sectional structure of each key top 56 will be described with reference to FIG.
20, 20,... Are selectively formed on the top surface of the key top 56 and shield the light from the LED 76. .. Are portions where the light-shielding films 20, 20,... Are not formed, and keys are displayed when light from the LED 76 passes through these portions.

Reference numeral 2 denotes a decorative layer formed so as to cover the upper surface and the side surface of the key top 56 on which the light shielding films 20, 20,... Are selectively formed. This is the same as the decorative layer 2 and will not be described in detail. Similarly, the light shielding film 20 and the decoration layer 2 are also formed on the upper surface of the top cover member 54.
Thus, the present invention can also be applied to a key unit in which each key top is made independent.

(Modification)
FIG. 6 is a cross-sectional view showing a key top 56a of a modification of the embodiment shown in FIG.
This key top 56a is formed by forming the decorative layer 2 on the back surface and further forming the light shielding films 20, 20,. In this case, the top cover member 54 also forms the decorative layer 2 and the light shielding film 20 on the back surface.
Thus, you may make it form the decoration layer 2 in the back surface of a keytop. When the light shielding film 20 and the decorative layer 2 are formed on the back surface of the key top 56a as described above, a transparent or white light-transmitting paint 26 is further applied on the light shielding film 20 and the decorative layer 2 so as to cover the light shielding film 20. It is desirable to fill the portions 22 and 22 where the light shielding film 20 is not formed.

  INDUSTRIAL APPLICABILITY The present invention is used for a decoration layer used for a key unit of an electronic device, for example, a mobile phone, a PHS, a personal digital assistant (PDA, etc.), a portable audio, a remote controller for home appliances, and a key unit equipped with the decorative layer. there is a possibility.

It is sectional drawing which shows one Example of this invention decoration layer. It is sectional drawing which shows one Example of the key unit using the decorating layer shown in FIG. (A) is a perspective view of the key unit when not illuminated, and (B) is a perspective view of the key unit when illuminated. The transmittance of the decorative layer with respect to each wavelength [nm] for three types of decorative layers having different reflected light colors (colors at a relatively vertical viewing angle) of purple, white, and yellow It is a related figure which shows [% T]. (A), (B) shows the Example which applied this invention to the key unit of the type in which each keytop became independent, (A) is a disassembled perspective view, (B) is a cross section which shows one keytop. FIG. It is sectional drawing which shows the key top of the modification of the key unit shown in FIG. It is sectional drawing of the prior art example of a decoration layer. It is a related figure which shows the transmittance [% T] of each wavelength [nm] of the decorative layer of the conventional example shown in FIG.

Explanation of symbols

2 ... decorative layer, 4 ... base film,
6a, 6b, 8a, 8b ... dielectric layer,
20 ... light shielding film, 22 ... non-formation part of light shielding film,
28 ... key base, 30 ... pusher, 32 ... wiring board,
34 ... light emitting diode, 36 ... metal dome.
52 ... Key unit, 56, 56a ... Key top.

Claims (3)

A decorative layer, wherein one or a plurality of dielectric layer laminates obtained by laminating a plurality of dielectric layers so as to have different refractive indexes of those in contact with each other are laminated on a light-transmitting base. A dielectric layer laminate in which a plurality of dielectric layers are laminated so that at least the layers in contact with each other have different refractive indexes so that incident light from the front side is reflected at the interface of the dielectric layer. One or more decorative layers laminated on a base having
Display means for selectively displaying light for indicating a key; and
An illumination light source that generates light that is transmitted through the display means to display a key;
A key unit characterized by having at least. A plurality of key tops each having a light shielding film selectively formed on the top surface or the back surface for display;
A key base located below the key top;
A light source for illumination that irradiates the key top through the key base;
Having at least
One or a plurality of dielectric layer laminates in which a plurality of dielectric layers are laminated on at least the upper surface or the back surface of each key top so that the refractive indexes of those at least in contact with each other are different from each other on a light-transmitting base. A key unit characterized by forming a laminated decorative layer.

Images