PURPOSE: To make it possible to prevent sound from being generated by vibration of its button, by providing a key sheet having a projecting portion formed on its lower face corresponding to the center line of the button in the form the upper that face of the key sheet is pressed in contact with the lower face of the flange portion of the button.
CONSTITUTION: A key sheet 8 is provided which is made of a resilient material such as silicon rubber in the form of a rough flat plate and has a projecting portion 8a formed on its lower face corresponding to the center line of a button 1. In the case of incorporating the key sheet 8 into the device, when it is so formed that the distance h2 between the lower face of the flange portion 1b of the button 1 and the upper face of a key button 3 satisfies h2>h1, the key sheet 8 is bent upward due to its projecting portion 8a having a thickness h1 to force the upper face of the sheet in contact with the whole part of the lower face of the flange portion 1b of the button 1, thereby forcing the upper face of the flange portion 1b in contact with the lower face of a case 7. While the device is carried on an electronic apparatus such as a telephone or the like, therefore, the button 1 does not vibrate regardless of vibration of its component e.g., speaker.
IIDA SHINOBU
TAKAHASHI SATORU
