1. Field of the Invention
The present invention relates to an input device, more particularly, to an input device in which an input panel connected to a flexible circuit board is received in a chassis.
2. Description of the Related Art
Recently, input panels, such as touch panels or tablets, enabling the input of data with approaching or contacting input means, such as pen-shaped writing instruments or fingertips, have been widely used as data input means of electronic apparatuses, such as PDAs (Personal Digital Assistant) or game machines.
As a method of detecting coordinate information so as to input data to the input panel, there have been known various methods of various types including resistor film, electromagnetic induction, electrostatic, ultrasonic, and optical methods. FIG. 6 is a schematic sectional view illustrating an example of a known input device having a resistor film type input panel. As shown in FIG. 6, a pair of bases 28 and 29 having the same planar size are opposed relative to each other in an input panel 24 with a predetermined gap. In the inner surfaces of the bases 28 and 29, which are opposed to each other, a plurality of electrodes (not shown) are formed by a resistor film made of a light-transmitting material. Each of the electrodes is formed to extend from one end of the second base 29 that is disposed on the anti-input side of the input panel 24 and serves as an electrode terminal.
In addition, when a predetermined portion of the first base 28 disposed on the input side of the input panel 24 is pressed by a writing instrument (not shown), the first base 28 is bent so that the resistor film of the first base 28 comes in contact with the electrodes of the second base 29 disposed on the anti-input side. The input panel 24 detects coordinate information of the contact point by a resistance ratio between two electrodes at the contact point, and data based on the coordinate information is input to the input device.
The input panel 24 is connected to a flexible circuit board 32 that supplies electric power to the electrodes of the input panel 24. The flexible circuit board 32 is disposed between the bases 28 and 29, and the electrodes of the flexible circuit board 32 are electrically connected to the electrode terminal of the input panel 24.
An input device 23 includes a chassis 21 for receiving the input panel 24. The chassis 21 includes a side wall 25 opposed to the side surfaces of the input panel 24, a top wall 22 opposed to an outer peripheral edge of the top surface of the input side to press the top surface of the input panel 24, and a bottom wall 31 opposed to a bottom surface of the anti-input side to support the input panel 24. An opening 31a for exposing the central portion of the bottom surface in the input panel 24 to the outside is formed on the bottom wall 31. In addition, the chassis 21 receives the input panel 24 in its inner space (see JP-A-2003-157150 for reference).
In the input device 23, the flexible circuit board 32 connected to one end of the input panel 24 is bent along a front end 29a of the second base 29 in the inside of the chassis 21 so that the flexible circuit board 32 is inserted between the front end 29a of the second base 29 and the side wall 25 of the base 21. In addition, the flexible circuit board 32 extends along between the bottom wall 31 of the chassis 21 and the bottom surface of the input panel 24 while being inserted. Then, the flexible circuit board 32 is bent along an opening edge of the opening 31a of the bottom wall 31 and extends to the outside of the chassis 21.
With the recent trend toward small and thin electronic apparatuses such as game machines having the above-mentioned input device 23, it may be desired to decrease the thickness of the input device 23 itself. Accordingly, an attempt has been made to realize the small-thickness of the input device 23 by eliminating the top wall 22 of the chassis 21.
However, in the above-mentioned input device 23, the flexible circuit board 32 is inserted between the front end 29a of the second base 29 and the side wall 25 of the chassis 21. If the top wall 22 of the chassis 21 is not formed, the flexible circuit board 32 can be seen from the input side. Accordingly, by only eliminating the top wall 22, it is difficult to manufacture the input device 23 with small thickness and planarize the input device 23 to have a flat surface.
In addition, because the flexible circuit board 32 is disposed to extend to the outside or inside of the chassis 21, the flexible circuit board 32 is complicatedly bent while being inserted between the chassis 21 and the input panel 24. In this way, when the flexible circuit board 32 is complicatedly bent several times, the bending portion of the flexible circuit board 32 is easily fatigued. That is, the flexible circuit board 32 may experience disconnection of electrodes as well as other problems.