Electromagnet induced switch

• US 5,880,539 A
• Filed: 04/10/1997
• Issued: 03/09/1999
• Est. Priority Date: 12/05/1996
• Status: Expired due to Term

• Current Assignee: EJT Technologies Incorporated
• Original Assignee: Silitek Corporation (Lite-On Technology Corporation)
• Inventors: Chen, Rich
• Primary Examiner(s): PALADINI, ALBERT WILLIAM
• Application Number:
  US08/831,707
• Time in Patent Office: 698 Days
• Field of Search: 307/119, 307/116, 395/309, 361/139, 345/173, 345/168, 341/23, 341/22, 235/61 PE, 364/189
• US Class Current: 307/119
• CPC Class Codes: H03K 17/97 using a magnetic movable element
• CPC Class Codes: H03K 17/972 having a plurality of control members, e.g. keyboard
• CPC Class Codes: H03K 2017/9706 Inductive element

Abstract

The present invention relates to an electromagnet induced switch comprises a substrate having an upper and lower conductive membranes, a plurality of electromagnet induced switches and a circuit controlling device. The electromagnet induced switches are suitably mounted onto the substrate and are suitably controlled by the circuit controlling device (including an analog multiplexer, a signal amplifying device, a signal triggering device, a signal locking-up/deleting device, a CPU and a breaking point controlling device during operation.) By this arrangement, the depressing position can be suitably recognized and the resulted signal is suitably and properly processed by the CPU. Consequently, a quick, missing free, free of incorrect works, linear and silent inputting device is resulted.

Claims

1. A keyboard system, comprising

a keyboard array scanning device having

a plurality of electromagnet induced switches mounted thereon, each of said electromagnet induced switches including a magnet core,

a substrate having a plurality of through holes, each through hole corresponding to a magnetic core,

first conductive membranes disposed on a first surface of the substrate,

second conductive membranes disposed on a second surface of the substrate opposite the first surface,

a scanning line electrically connected to each first conductive membrane, and

a return line electrically connected to each second conductive membrane,

each first and second conductive membrane being positioned relative to a through hole such that, when a current in a first membrane adjacent to a through hole is varied while an electromagnet induced switch is depressed to thereby cause the corresponding magnet core to move down through said through hole, a current is induced in a second conductive membrane adjacent said through hole;

an encoder electrically connected to the scanning line;

a current and voltage controlling device electrically connected to each of the first and second conductive membranes to enhance the sensitivity of the keyboard system to current induced in a second conductive membrane;

a CPU electrically connected to the input port of said encoder;

an analog multiplexer electrically connected to said returning line and said CPU;

a signal amplifying device electrically connected to an output port of said analog multiplexer, to amplify the signal from said multiplexer;

a signal triggering device electrically connected to an output port of said signal amplifying device to receive a signal from said signal amplifying device and establish an upper and lower threshold for accuracy of the signal, so that the signal from said signal amplifying device can be categorized at a high or low level; and

a breaking point controlling device electrically connected to said signal amplifying device and also to said CPU, wherein said breaking point controlling device during operation receives the controlling signal from said CPU to obtain upper or a lower limits for correcting the triggering position.

2. A keyboard system as recited in claim 1, wherein each of said first and second conductive membranes form a concentric rings around adjacent through holes in said substrate.

3. A keyboard system as recited in claim 1, wherein a conducting line of either said first or second conductive membrane is connected to said current and voltage controlling device.

4. A keyboard system as recited in claim 1, wherein said first conductive membranes are arranged perpendicular to the second conductive membranes.

5. A keyboard system as recited in claim 1, wherein each electromagnet induced switch includes a key stem having a plunger thereon, said magnet core being attached to said plunger.

6. A keyboard system as recited in claim 1, wherein a scanning process performed on said keyboard array scanning device is a multiple scanning.

7. A keyboard system as recited in claim 2, wherein said first conductive membranes are arranged perpendicular to the second conductive membranes.