Fluorescent optical switch and keyboard apparatus

• US 4,617,461 A
• Filed: 04/25/1984
• Issued: 10/14/1986
• Est. Priority Date: 04/25/1984
• Status: Expired due to Fees

• Current Assignee: Unisys Corporation
• Original Assignee: Burroughs Incorporated (Terreno Realty Corp.)
• Inventors: Ely, Richard I., Subbarao, Wunnava V.
• Primary Examiner(s): Laroche, Eugene R.
• Assistant Examiner(s): Mottola, Steven J.
• Application Number:
  US06/603,876
• Time in Patent Office: 902 Days
• Field of Search: 250/221, 250/229, 250/234, 250/235, 250/462.1, 330/59, 330/308, 340/36 SP
• US Class Current: 250/229
• CPC Class Codes: H03K 17/969 having a plurality of control members, e.g. keyboard

Abstract

Fluorescent optical switch and keyboard apparatus wherein a plurality of fluorescent optical key switches are arranged in a matrix array of rows and columns with a key disposed at each column-row intersection and wherein each key carries a fluorescent optically reflective element thereon. A single optical photo-diode disposed at each key location is caused to operate in three discrete modes with respect to the fluorescent element. In one mode the diode emits light which is caused to be reflected upon key when the key is depressed. In another mode the reflected light striking the diode causes the diode to act as a photo-receptor effectively indicating key actuation.

Claims

1. Fluorescent optical switch and keyboard apparatus comprising:

photo-optical means adapted to operate in a light emitting, a light receiving and a passive mode,

fluorescent means disposed adjacent to said photo-optical means and capable of movement from a light blocking to a light passing position, and

circuit means interconnected to said photo-optical means for energizing said photo-optical means to a level causing said photo-optical means to emit light for impingement upon said fluorescent means when said fluorescent means is disposed in a light fluorescent position, said circuit means thereafter biasing said photo-optical means so as to cause said photo-optical means to act as a light receptor and to generate an electrical signal output indicating the actuation of the device.

2. The combination according to claim 1 wherein said photo-optical means further comprises a photo-diode.

3. The combination according to claim 1 wherein said fluorescent means is carried by the key stem of a photo-optical keyboard.

4. The combination according to claim 1 wherein said fluorescent means comprises a fluorescent coating on a support structure.

5. Fluorescent optical switch and keyboard apparatus comprising:

a matrix array of rows and columns of keys arranged to form a keyboard,

a photo-diode disposed adjacent to the key stem of each key,

a fluorescent material having a delay time commensurate with the response time of said photo-diode coated on one portion of said key stem,

electrical circuit means for biasing said photo-diode first in a forward direction so as to cause the diode to emit light for impingement upon the fluorescent material and for then biasing said photo-diode in the reverse direction causing said diode to act as a light receptor, and

microprocessor means for controlling the electrical signals input to and output from said photo-diode effective to indicate key actuation.

6. The combination according to claim 5 further including a row driver for each row of photo-diode and being capable of responding to three discrete states of operation of said diodes.

7. The combination according to claim 5 wherein said microprocessor means further includes a separate amplifier for each column of photo-diode.