Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making named article
Reexamination Certificate
1998-10-13
2001-02-13
Huff, Mark F. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making named article
C430S945000
Reexamination Certificate
active
06187514
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a method for forming a pad character in a key top for a push button switch which is used for a data input unit for a mobile communication equipment, a switch unit or the like and a method for manufacturing a cover member for a push button switch, and more particularly to a method for irradiating a key top with a laser beam to form an indication such as a character or the like in the key top.
A push button switch for a data input unit for a mobile communication equipment such as a cellular phone, a key board for a personal computer or the like is generally constructed by mounting a cover member directly on a circuit board. In such a push button switch, a substrate which includes a plurality of movable sections is formed of a rubber elastomer. The movable sections are each provided on a front surface thereof with a key top and on a rear surface thereof with a movable contact. The key top is formed on a top surface thereof with a figure, a character or the like by printing, to thereby provide a cover member.
In the cover member thus constructed, the top surface of each of the key tops functions as an operation section or a pressed surface with which a finger of an operator is contacted, when the cover member is mounted on the circuit board to constitute the push button switch. Thus, use of the push button switch for a long period of time causes the figure, character or the like on the top surface of the key top to be worn due to contact with the finger, leading to a deterioration in visibility of the figure or the like.
A cover member intended to improve wear resistance of a character, a figure or the like on a top surface of a key top is proposed in Japanese Patent Application Laid-Open Publication No. 169360/1995. More specifically, the publication discloses a method for manufacturing a cover member wherein a key top is formed on a top surface thereof with a recess of 5 to 50 &mgr;m in depth in any desired design by means of a forming die concurrently with formation of the key top, and then a colored section is formed of an ink of 150 to 400 p (poise) in the recess by screen printing by means of a polyester screen which was subjected to plasma processing so as to have a mesh density of 300 to 500 meshes/inch.
However, the method disclosed in the Japanese publication requires to form the forming die for the key top with fine projections for forming the recess, so that working or machining of the forming die is highly troublesome and durability of the forming die is deteriorated. Also, the method requires formation of the recess and applying of the coloring ink in the recess, to thereby increase the number of steps in the manufacturing, leading to an increase in manufacturing cost. Further, use of the cover member for a prolonged period of time often causes falling-off of the coloring agent or ink from the recess, so that the key top is deteriorated in being comfortable to fingers.
SUMMARY OF THE INVENTION
The present invention has been made in view of the foregoing disadvantages of the prior art.
Accordingly, it is an object of the present invention to provide a method for forming a pad character in a push button switch which is capable of simplifying formation of the pad character.
It is another object of the present invention to provide a method for forming a pad character in a push button switch which is capable of permitting a push button switch to be manually operated in a manner comfortable to fingers over a prolonged period of time while preventing wearing of an indication section.
It is a further object of the present invention to provide a method for manufacturing a cover member for a push button switch which is capable of simplifying the manufacturing.
It is still another object of the present invention to provide a method for manufacturing a cover member for a push button switch which is capable of providing a cover member which is satisfactory to the touch with the fingers over a long period of time while preventing wearing of a display section.
In accordance with one aspect of the present invention, a method for forming a pad character in a push button switch is provided. The method includes the steps of: coating a pigment particle with a volatilization layer made of resin blended with an electromagnetic wave absorbing powder to prepare a laser-sensitive color developing agent; forming a key top of a light-permeable thermosetting resin or elastomer material blended with the laser-sensitive color developing agent; and irradiating the key top with a laser beam to form therein an indication section of the pigment particle.
In accordance with another aspect of the present invention, a method for manufacturing a cover member for a push button switch in which a substrate including a base section and movable sections displaceable with respect to the base section is integrally formed of a rubber composition and the movable sections of the substrate are each securely mounted thereon with a key top is provided. The method includes the steps of: coating a pigment particle with a volatilization layer made of resin blended with an electromagnetic wave absorbing powder to prepare a laser-sensitive color developing agent; forming each of the key tops of a light-permeable thermosetting resin or elastomer material blended with the laser-sensitive color developing agent; irradiating each of the key tops with a laser beam to form therein an indication section of the pigment particle; and fixing each of the key tops formed with the indication to a respective one of the movable sections integrally.
Also, in accordance with this aspect of the present invention, a method for manufacturing a cover member for a push button switch in which a substrate including a base section and movable sections displaceable with respect to the base section is integrally formed of a rubber composition and the movable sections of the substrate are each securely mounted thereon with a key top is provided. The method includes the steps of: coating a pigment particle with a volatilization layer made of resin blended with an electromagnetic wave absorbing powder to prepare a laser-sensitive color developing agent; forming a light-permeable thermosetting resin or elastomer material blended with the laser-sensitive color developing agent into each of the key tops; fixing each of the key tops to a respective one of the movable sections integrally; and irradiating each of the key tops fixed on the substrate with a laser beam to form therein an indication section of the pigment particle.
In a preferred embodiment of the present invention, the fixing is carried out by die-forming a rubber elastomer into the substrate while using each of the key tops as an insert.
In a preferred embodiment of the present invention, the fixing is carried out by adhering each of the key tops to a front surface of a respective one of the movable sections of the substrate.
In a preferred embodiment of the present invention, the pigment particle has a particle diameter of 30 to 50 &mgr;m.
In a preferred embodiment of the present invention, the electromagnetic wave absorbing powder has a particle diameter equal to or smaller than a wavelength of the laser beam.
The present invention constructed as described above may be realized in the form of a push button switch typically incorporated in a data input unit of a cellular phone or a keyboard of a personal computer, irrespective of whether it is of either the illumination type or the non-illumination type. In such a push button switch, each of the key tops is urged by means of a mechanical elastic member such as a coiled spring, a leaf spring or the like and combined with the substrate made of a rubber elastomer to constitute the cover member.
The substrate has the key tops made of the thermosetting resin or elastomer material and fixed to the respective movable sections thereof as described above and is mounted directly or through a click plate or the like on a circuit board provided thereon with fixed contacts, to thereby constitute the
Kiyosawa Mikio
Kuroiwa Kinji
Nakano Sadao
Barreca Nicole
Huff Mark F.
Lerner David Littenberg Krumholz & Mentlik LLP
Shin-Etsu Polymer Co. Ltd.
LandOfFree
Method for forming pad character in push button switch and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for forming pad character in push button switch and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for forming pad character in push button switch and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2607227