Optical keyboard

• US 4,387,367 A
• Filed: 06/19/1981
• Issued: 06/07/1983
• Est. Priority Date: 06/19/1981
• Status: Expired due to Fees

• Current Assignee: Charles R. Fisher
• Original Assignee: Charles R. Fisher
• Inventors: Fisher, Charles R.
• Primary Examiner(s): Robinson, Thomas A.
• Application Number:
  US06/275,417
• Time in Patent Office: 718 Days
• Field of Search: 340/365 P, 178/17 D, 178/18, 250/221, 250/578, 250/553
• US Class Current: 341/31
• CPC Class Codes: H03K 17/943 using a plurality of optical emitters or detectors, e.g. keyboard

Abstract

A matrixed, optical keyboard comprising structure 10 defining an array of touch areas 14 arranged in rows 16 and columns 17, and paired light sources and light sensors 20, 22 disposed at opposite ends of each row and each column and positioned to define a path of light. Light refocussing elements 24 are disposed contiguously about and define the touch areas and extend into the light path thereby refocussing the light beam prior to traversing each touch area and prior to impinging on the associated light sensor. In one embodiment, the keyboard and light refocussing elements are integrally molded and form a unitary structure. In another embodiment, the keyboard is formed with structure for maintaining an indicia card 44 behind and in alignment with the touch areas so that indicia area 44a are visible through the touch areas 14'"'"'.

Claims

1. A matrix switch apparatus, comprising:

(a) a panel defining an array of key areas arranged in rows and columns;

(b) a paired light source and light receptor associated with each row, each pair determining a path of light extending across its associated row and above the surface of said panel, said light source and light receptor of each row pair disposed at opposite ends of their associated row and outside of said key areas defining said row;

(c) a paired light source and light receptor associated with each column, each pair determining a path of light extending across its associated column and above the surface of said panel, said light source and light receptor of each column pair disposed at opposite ends of their associated column and outside of said key areas defining said column; and

,

(d) light refocusing elements disposed along the perimeter of each key area and in the path of the column and row light beams, each element including light refracting surfaces for refocusing said row and column light beams traversing the associated key area.

2. The apparatus of claim 1 wherein said light refocusing elements define the perimeter extent of said key areas.

3. The apparatus of claim 1 wherein said panel and refocusing elements are integrally molded and form a unitary structure.

4. The apparatus of claim 1 wherein said panel is formed from a transparent material and said apparatus further comprises means for maintaining an indicia carrying card along a rear surface of said panel, said indicia being aligned with said key areas.

5. A data entry device, comprising:

(a) structure defining an array of touch areas arranged in columns and rows;

(b) a light source and a light sensor disposed at opposite ends of each row and each column and positioned to define a path of light associated with each row and each column that traverses said associated row and column a predetermined distance above said touch areas;

(c) light focusing elements forming part of rod-like members disposed contiguously about said touch areas and defining the perimeter thereof, said elements extending into the light path and operative to focus said light path at periodic intervals thereby reducing the light dispersion of the light beams traversing the rows and columns.

6. The apparatus of claim 5 wherein said touch areas are located in a common place.

7. The apparatus of claim 5 wherein said light focusing elements are integrally formed with said touch area structure.