Electricity: circuit makers and breakers – Multiple circuit control – Multiple switch
Reexamination Certificate
2002-10-01
2004-04-06
Easthom, Karl D. (Department: 2832)
Electricity: circuit makers and breakers
Multiple circuit control
Multiple switch
C200S004000, C200S512000, C200S341000
Reexamination Certificate
active
06717074
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a membrane button key structure for electronic devices and particularly a membrane button key structure with a built-in speaker.
BACKGROUND OF THE INVENTION
Due to continuous innovations of electronic techniques and rapid developments of digital technologies, 3C information products have become indispensable outfits and helpful working tools for many people. 3C information products include notebook computers, mobile phones, personal digital assistants (PDAs), Palm computers (Palms) and the like. PDA, because of its powerful functions, user-friendliness and light and compact size, has been widely accepted by consumers. In addition, PDA can also include many other functions such as to access the Internet in a wireless fashion, communication, and video/audio enabling. It has becomes a prevailing trend of the information product development nowadays.
Refer to
FIG. 1
for a conventional PDA. It includes a casing
10
, a display panel
12
and a membrane key
14
. The casing
10
has a plurality of openings formed on the surface to match and accommodate the display panel
12
and the membrane key
14
. The keys
140
of the membrane key
14
are extending above the openings. Users can depress the keys
140
to perform the operations of the PDA. The information are displayed on the display panel
12
.
Refer to
FIG. 2
for the membrane key of adopted by conventional techniques. The membrane key
20
includes a four-way key
21
and a plurality of hot keys
22
. The keys
21
and
22
are interconnected by a membrane
23
. The entire membrane key
20
is integrally formed from a pliable rubber. The four-way key
21
has four bulged points
24
located on a lower side of four corners. Each hot key
22
also has a bulged point
22
located thereunder. There is a circuit board
25
located below the membrane key
20
. The circuit board
25
has a plurality of touch switches
26
located on the surface thereof. The bulged points
24
below the keys
21
and
22
correspond to the touch switches
26
of the circuit board
25
. Users may enter input commands on the PDA by depressing the keys
21
and
22
to move the bulged points
24
located therebelow in contact with the touch switches
26
of the circuit board
25
. The input commands are processed and the results are displayed on the display panel (not shown in the drawings).
These days, PDA equipped with video/audio or mobile phone capabilities has become a hotly pursued trend. One of the critical elements to achieve the aforesaid functions is the speaker. To make the PDA competitive, it must by lean and light, and has a big enough display screen. To meet those requirements, conventional techniques of PDA have fully utilized the internal space of the casing for the configuration of the necessary elements and keys. It is very difficult to allocate an additional space for the speaker. When trying to adopt the conventional techniques to add the speaker on the front side of the PDA without increasing the total size, the size of the display panel has to be shrunk. To keep the speaker on the front side of the PDA without reducing the size of the display panel, total size of the PDA should be increased. To install the speaker on the rear side of the PDA will increase the total thickness. Besides, when the speaker is located on the rear side of the PDA, the audio quality is not desirable. When it is coupled with the mobile phone, the voice output from the rear side has the risk of being eavesdropped.
Because of the conventional techniques have difficulty to include the speaker in the PDA and still meet the requirements of lean and light and a large enough display screen, it is necessary to develop new techniques to resolve the problem.
SUMMARY OF THE INVENTION
Therefore the primary object of the invention is to provide a membrane button key structure with a built-in speaker to offer PDAs or the related electronic products with audio function without increasing the thickness and size of the product, or reducing the size of the display screen.
The membrane button key structure with a built-in speaker of the invention is adopted for use on PDAs or the related electronic products. The PDA includes a circuit board which has a plurality of touch switches and a carved opening on the surface thereof. The invention includes a membrane key, a bottom lid and a speaker. The membrane key consists of a four-way key and a plurality of hot keys interconnected by a membrane which is integrally made from a pliable rubber. The four-way key has four bulged points located on bottom side of four corners. Each hot key also has a bulged point located on the bottom in the center thereof. When the membrane key is coupled above the circuit board, each key located under the membrane key corresponds to a touch switch of the circuit board. The center of the four-way key is above the carved opening. The bottom lid is under the carved opening and forms a housing compartment with the four-way key for housing the speaker in the middle thereof. The space between the speaker and the four-way key becomes an upper acoustic chest and the space between the speaker and the bottom lid becomes a lower acoustic chest.
The invention aims at installing the speaker below the four-way key of the membrane key without increasing the total thickness and size of the PDA, or reducing the size of the display screen. The circuit board below the four-way key is properly carved to coupled with a bottom lid to form a housing compartment with the four-way key. Therefore, the speaker may be installed in the PDA to generate a desired audio effect without increasing the total thickness and size of the PDA, or reducing the size of the display screen. In order to form the carved opening on the circuit board, the circuit layout on the circuit board has to be properly designed to prevent from being interrupted. In addition, the interior of the four-way key and function keys is formed in a hollow manner to increase the acoustic space of the acoustic chest to improve the sound quality of the speaker. The bulged points to contact the touch switches of the circuit board are maintained. The membrane connecting the keys has troughs formed on the bottom thereof to communicate with the hollow space of the hollow keys so that the space of the acoustic chest may be increased to improve the sound quality of the speaker.
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
REFERENCES:
patent: 4081631 (1978-03-01), Feder
patent: 6049290 (2000-04-01), Halstead
patent: 6297806 (2001-10-01), Skoog
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