1. Field of the Invention
The present invention relates to an operation input device which is applicable to a portable telephone or a portable music player.
2. Description of the Related Art
Heretofore, an operation input device for use in a portable telephone or the like has been, for example, one including a base, a printed circuit board which has a plurality of pushbutton switches and magnetic field detecting elements mounted on its upside and which is stacked on and united with the base, an operation plate which is placed on the printed circuit board, and a disc type operation dial in which an annular magnet with N-poles and S-poles arranged alternately is assembled on the underside of the operation dial and which is turnably assembled on the operation plate. With the operation input device, the operation dial is turned, whereby the changes of the magnetic fluxes of the annular magnet are sensed by the magnetic field detecting elements so as to detect a turning direction, while the operation dial is depressed, whereby the pushbutton switch is operated (refer to JP-A-2003-280799).
The operation input device is schematically shown in FIG. 19. As seen from the figure, the peripheral edge of a rotary member (operation dial) 154 is retained through a retaining ring 164 which is mounted on a base 120. Here, the rotary member (operation dial) 154 is subjected to a turning operation and a depressing operation, thereby to drive any of pushbutton switches not shown. In this case, when the upper peripheral edge of the rotary member 154 abuts against the retaining ring 164 in depressing the peripheral edge of this rotary member 154, an operation feeling worsens, and hence, some gap G1 is provided. Due to the provision of the gap G1, however, the rotary member 154 becomes rickety in a vertical direction. It is therefore considered to urge the rotary member 154 upwards by elastic members. With such a configuration, however, the retaining ring 164 and the upper peripheral edge of the rotary member 154 come into touch, and a friction develops in subjecting the rotary member 154 to the turning operation. This leads to the problem that a smooth turning operation is not attained.