Etching a substrate: processes – Forming or treating an ornamented article
Reexamination Certificate
2001-11-07
2004-08-03
Norton, Nadine G. (Department: 1765)
Etching a substrate: processes
Forming or treating an ornamented article
C216S054000, C029S622000, C379S433020, C428S137000, C428S195100, C400S472000, C200S341000
Reexamination Certificate
active
06770212
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for the manufacture of a key top for a push button switch preferably used in input devices such as cellular phones and keyboards.
2. Description of Related Art
Switches having a structure consisting of a rubber contact switch and a key top installed on the top portion of the key switch have been generally used as push button switches employed in cellular phones and the like.
Push button switches are also required to have excellent appearance, and the demand for metallic-like switches of this type has recently increased. Technology relating to methods for the manufacture of metallic-like push button switches (referred to as “metallic switches” hereinbelow) of an illumination type, which are used in portable phones, was disclosed in Examined Japanese Patent Application No. 3-23915 and Unexamined Japanese Patent Application 2000-176659. In accordance with this technology, a metal layer is formed on a key top and then part of the metal is evaporated and dissipated with a laser to obtain letters, symbols and the like. Furthermore, when colored, e.g., red or blue, metallic switches rather than switches with metallic colors are manufactured, a transparent colored layer is formed on the key top surface, then a metal layer is formed, and only a metal layer is evaporated with a laser.
However, with the above-described method, because laser processing is employed, mass production is difficult to Implement. Furthermore, since the entire procedure, from the first to the last stage, is conducted on the key top, if a defect occurs in the last stage, all the preceding operations become useless and the productivity is poor.
Furthermore, when a colored metallic button is manufactured, though the metal layer is removed with a laser, the transparent colored layer is not removed and remains as is. Thus, in order to remove the metal layer, a short-wavelength laser radiation such as that of YAG (yttrium aluminum garnet) laser has to be used, such short-wavelength laser radiation penetrating through plastics. Therefore, the problem associated with such a method is that the transparent colored layer remains without changes and the color of the light that penetrates through the metallic button is restricted to the color of the colored layer.
SUMMARY OF THE INVENTION
With the foregoing in view, it is an object of the present invention to provide a method for the manufacture of a metallic switch which allows high productivity. It is also an object of the invention to provide a colored metallic switch with a high added value, in which no limitation is placed on the color of the transmitted light.
The method for the manufacture of a metallic switch in accordance with the present invention, which attains the above-described objects, comprises the steps of forming a metalizing layer on the surface of a transfer substrate, forming a first transparent printed layer patterned as letters, numbers, symbols, pictures, and the like and having resistance to etching on the metalizing layer, removing the metalizing layer which is not masked by the transparent printed layer by etching, placing the transfer substrate on the plastic key top body, and transferring the transfer layer consisting of the metalizing layer and masking material layer after etching onto the key top body.
Thus, transferring of the masking material (first transparent printed layer) which, within the framework of the conventional technology, was considered merely as a protective layer for etching and was removed after etching onto the key top body integrally with the metalizing layer, makes it unnecessary to remove the masking material. Moreover, the metalizing layer which has a low strength and can be easily fractured is protected and reinforced by the transparent printed layer. Therefore, transferring of the metalizing layer can be conducted with high stability, and a metallic switch can be manufactured in an easy and efficient manner.
The transfer layer may be transferred either on the front or rear surface of the key top body, and the transfer operation is conducted so that the first transparent printed layer is brought in contact with the key top body. When the transfer layer is transferred onto the front surface of the key top, the metalizing layer is at the front surface side of the key top and a metallic switch with a color of the metalizing layer is obtained. When the transfer layer is transferred onto the rear surface of the key top, the transparent printed layer is at the front surface side of the key top and, if a colored transparent printed layer is used, the metalizing layer is colored and a colored metallic switch is obtained.
In order to transfer the transfer layer, a hot press method can be used. If the first transparent printed layer demonstrates stickiness during heating, the direct transfer to the key top body is possible. However, if a transparent adhesive layer is formed on the transparent printed layer, the transfer layer can be transferred onto the key top body with higher reliability and without the danger of misalignment.
No specific restriction is placed on the transfer substrate, provided that it is highly flexible and resistant to beat and etching. Examples of suitable materials include films or sheets of plastics with high heat resistance and mechanical strength such as PET (polyethylene terephthalate). If such flexible transfer substrate is used, even when the transfer layer is formed on the key top body having peaks and valleys, the transfer substrate follows the curved surface and can be reliably laminated onto the key top body. Therefore, the number of printing defects occurring in the metalizing layer and first transparent printed layer can be decreased by comparison with the case when the printed layer is formed directly on the key top body.
In accordance with the present invention, the metalizing layer and transparent printed layer are formed separately from the key top body, and those layers are transferred onto the key top only in the final stage. Therefore, the defect ratio in the key tops as a final product can be reduced. Furthermore, the metalizing layer and transparent printed layer are formed on a film- or sheet-like substrate rather than on the key top body having high rigidity. Therefore, the substrate can be supplied as a roll. If the substrate is coiled up into rolls and stored after the metalizing layer and transparent printed layer have been formed, the transfer substrate serves as a protective layer for both layers. Therefore, the substrate can be handled easily and space for manufacturing equipment can be saved.
The first transparent printed layer is patterned as letters, numbers, symbols, pictures, and the like, and the metalizing layer in the portion thereof which is not covered with the printed layer is removed by etching. Therefore, when the transparent printed layer is colored and the transfer layer is transferred onto the rear surface of the key top body, only portions where the metalizing layer is present are colored, and portions from which the metaling layer has been removed are in a state in which the transparent printed layer has also been removed. Therefore, a metalizing switch with a high added value can be provided without placing a limitation on the color of the light that passes through the switch, while coloring the metalizing layer portions.
Furthermore, if a second transparent printed layer is formed on the surface of a transfer substrate prior to the step of forming the metalizing layer and then the transfer layer containing the second transparent printed layer is transferred onto the back surface of the key top body, a key top is obtained in which the metalizing layer is covered and protected by the second transparent printed layer. Thus, the damage, peeling, or modification of the metalizing layer can be prevented.
If a colored layer is used as the second transparent printed layer in the above-described process, the light that passes through the metallic switch can be colored appr
Ahmed Shamim
Atryz Yodogawa Co., Ltd.
Norton Nadine G.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Key top and method for manufacture thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Key top and method for manufacture thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Key top and method for manufacture thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3349645