TOUCH RESPONSIVE ELECTRIC SWITCH AND DEVICE FOR THE USE THEREOF

• US 3,772,685 A
• Filed: 03/29/1972
• Issued: 11/13/1973
• Est. Priority Date: 03/29/1972
• Status: Expired due to Term

• Current Assignee: Allied Corp. (Honeywell International Inc.)
• Original Assignee: James Vincent Masi
• Inventors: Masi, James Vincent
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Curtis, Marshall M.
• Application Number:
  US05/239,117
• Time in Patent Office: 594 Days
• Field of Search: 350/16R,16P,267 340/324R,365 250/213A
• US Class Current: 341/31
• CPC Class Codes: B66B 1/463 Touch sensitive input devices
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0202 Constructional details or processes of manufacture of the input device
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: H01R 43/28 for wire processing before connecting to contact members, not provided for in groups H01R43/02 - H01R43/26
• CPC Class Codes: H03K 17/962 Capacitive touch switches

Abstract

A high impedance, low voltage, electro-optic light valve, such as, for example, a liquid crystal cell, has one terminal connected to a source of varying potential and the other terminal connected to an element adapted to be touched by a person or otherwise contacted by an impedance path to a potential which is highe or lower than the varying potential by an amount at least equal to the excitation potential of the valve. When the element is contacted, a circuit is completed through the valve, causing its optical characteristics to change. A touch (contact) responsive switch is provided by detecting the change in the optical characteristics of the valve and by generating some sort of output in response thereto. The switch may be utilized in devices such as a keyboard, a cable conductor identifier, or a touch response matrix board where an indication is required as to which of a plurality of elements has been touched or otherwise contacted. For such applications, the elements to be touched are connected through a suitable coding means to a bank of valves. The outputs from the valve detectors indicate, in a suitable code, the element touched. This invention relates to a low current electric switch which may be actuated in response to a person touching an element and to various devices, including an electronic keyboard, a cable conductor identifier, and a touch responsive matrix board, utilizing the switch.

Claims

1. An electric switch comprising:

a high impedance, low voltage electro-optic light valve having terminals on opposite sides thereof, said valve being adapted to have its optical characteristics changed when a potential exceeding a predetermined threshold potential is applied across the valve;

means for applying a potential to one terminal of said valve;

an electrically conductive member which is normally open circuited;

means for electrically connecting the other terminal of said valve to said member;

said member being adapted to be touched in a manner to provide a high impedance path to a potential source which is higher or lower than the potential applied to said one terminal by an amount at least equal to the excitation potential of said valve, a circuit being completed through said valve when said member is touched causing the optical characteristics of said valve to change; and

means for detecting the change in the optical charcteristics of said valve, and for generating an electrical output in response thereto.

2. A switch of the type described in claim 1 wherein said light valve is a liquid crystal cell.

3. A switch of the type described in claim 2 wherein said cell includes a layer of liquid crystal material sandwiched between layers of conductive material;

and wherein said member is electrically connected to one of said layers of conductive material.

4. A switch of described type dexcribed in claim 1 wherein potential applied to said one terminal is varied in accordance with some pattern.

5. A switch of the type described in claim 4 wherein the potential applied to said one terminal is an AC potential.

6. A switch of the type described in claim 1 wherein said member is adapted to be touched by a person, said person serving as a high impedance path to ground.

7. A switch of the type described in claim 6 wherein said member is a metal cap connected through suitable means to said one terminal of the valve.

8. A switch of the type described in claim 7 wherein there are more than one of said valves;

and wherein said suitable means includes coding means selectively connecting said first element to one or more of said valves.

9. A switch of the type described in claim 1 wherein said detecting means includes a light source and a photo-detector device, said light source and photo-detector device being positioned relative to each other so that said photo-detector device is energized by said light source when the optical characteristics of said valve are in one but not the other of the conditions they may be in.

10. A switch of the type described in claim 9 wherein said light source is a light emitting diode.

11. A device for detecting a person touching an element and for generating an electrical output in response thereto comprising:

a high impedance, low voltage, electro-optic light valve having terminals on opposite sides thereof, said valve being adapted to have its optical characteristics changed when a potential exceeding a predetermined threshold potential is applied across the valve;

means for applying a varying potential to one terminal of said valve;

means for physically and electrically connecting the other terminal of the valve to said element, a circuit being completed through said valve when said element is touched, causing the optical characteristics of said valve to change; and

means for detecting the change in the optical characteristics of said valve and for generating said electrical output in response thereto.

12. A device for detecting the touching of one of a plurality of elements and for indicating the element touched comprising;

a plurality of high impedance, low voltage, electro-optic light valves, each of said valves being adapted to have its optical characteristics changed when a potential exceeding a predetermined threshold potential is applied across the valve;

means for selectively connecting each of said elements to one side of at least one of said light valves, a varying potential being applied to the other side of each of said valves, and a circuit being completed through each valve to which a touched element is connected causing a change to occur in the optical characteristics of each such valve;

means for detecting the change in the optical characteristics of the valves; and

means responsive to said detecting means for generating an indication of the element touched.

13. A device of the type described in claim 12 wherein the means for selectively connecting includes coding means for converting a single input from the element touched into a plurality of outputs to said valves.

14. A device of the type described in claim 13 wherein said device is an electronic keyboard;

wherein said elements are the keys of said keyboard, said keys being caps of conductive material embedded in an insulating plate; and

wherein said coding means includes means for connecting each of said caps to a plurality of outputs to said valves, said outputs representing, in a selected code, the character designated by the key touched.

15. A device of the type described in claim 13 wherein said element is a conductor of a cable, the end of the conductor opposite the end being touched being connected to a terminal which may be characterized by certain identifying characters;

and wherein the outputs from said coding means represent in a selected code the identifying characters of said terminal.

16. A device of the type described in claim 15 wherein said identifying characters are numbers and said selected code is a binary code.

17. A device of the type described in claim 15 wherein said indication generating means includes means for converting the response to said detecting means into a display code of said terminal identifying characters, and means responsive to said converting means for displaying said identifying characters.

18. A device of the type described in claim 13 wherein said element is the tip of a conductor which is either flush with or projecting slightly from the face of a plate of insulating material.

19. A device of the type described in claim 18 wherein there are a plurality of said conductor tips positioned in a predetermined pattern on thE face of said plate;

and wherein said coding means includes means for generating an indication of the coordinates of each of said conductors.

20. A device of the type described in claim 19 wherein said plate is of a transparent material and is adapted to be positioned in front of the face of a cathode ray tube.

21. A device of the type described in claim 12 wherein said light valves are liquid crystal cells.

22. A device of the type described in claim 12 wherein said detecting means includes a light source and a photo-detector device, said light source and photo-detector device being positioned relative to each other so that said photo-detector device is energized by said light source when the optical characteristics of said valve are in one but not the other of the conditions they may be in.

23. A device of the type described in claim 22 wherein there is a light source and a photo-detector device for each of said valves.

24. An electronic keyboard comprising:

a plurality of character designating keys, each formed of a conductive material;

a plurality of high impedance, low voltage, electro-optic light valves, each of said valves being adapted to have its optical characteristics changed when a potential exceeding a predetermined threshold potential is applied across the valve;

means for connecting each of said keys to one side of a selected one or more of said light valves, the light valves to which each of said keys is connected representing, in a selected code, the character designated by the key;

means for applying a varying potential to the other side of each of said light valves;

whereby when a key is touched, a high impedance path to ground is provided, completing a circuit through each valve to which the touched key is connected, causing the optical characteristics of each said valve to change;

means for detecting the change in optical characteristics of each of said valves; and

means responsive to said detecting means for generating coded outputs representing the designated character for each touched key.

25. A device operative when a conductor of a cable is contacted at one end, for indicating which one of a plurality of terminals the other end of the cable conductor is connected to comprising:

a plurality of high impedance, low voltage, electro-optic light valves, each of said valves being adapted to have its optical characteristics changed when a potential exceeding a predetermined threshold potential is applied across the valve;

means for electrically connecting each of said terminals to one side of at least one of said light valves, an AC potential being applied to the other side of each said valves, and a circuit being completed through each valve to which a terminal is connected when the conductor connected to the terminal is contacted at said one end, causing the optical characteristics of each such valve to change;

means for detecting the change in optical characteristics of the valves; and

means responsive to said detecting means for indicating the terminal connected to the conductor which is contacted at said one end.

26. A device for generating an indication of the coordinates of a point which is contacted in a selected manner comprising:

a plate of insulating material having a plurality of conductors positioned therein with their tips either flush with or projecting slightly from the upper surface of said plate, said conductor tips being arranged in a predetermined pattern;

a plurality of high impedance, low voltage, electro-optic light valves, each of said valves being adapted to have its optical characteristics changed when a potential exceeding a predetermined threshold potential is applied across the valve;

means for connecting each of said conductors to one side of selected ones of at least one group of said light valves, the light valves to which each of said conductors is connected representing in a selected code the coordinates of the position of said condUctor in the plate;

means for applying a varying potential to the other side of each of said light valves;

whereby when a conductor is contacted, a circuit is completed through each valve to which the contacted conductor is connected, causing the optical characters of each said valve to change;

means for detecting the change in optical characters of each of said valves; and

means responsive to said detecting means for generating outputs in a selected code representing the coordinates of the contacted conductor.

27. A device of the type described in claim 26 wherein said point is contacted by being touched by a person.

28. A device of the type described in claim 26 wherein said predetermined pattern is a matrix grid.

29. A device of the type described in claim 27 wherein said insulating plate is of a transparent material and is adapted to be positioned in front of a cathode ray tube (CRT) to permit points on the CRT screen to be identified and an indication of the coordinates of the identified points to be generated.

30. An electric switch comprising:

A high impedance, low voltage, electro-optic light valve having terminals on opposite sides thereof, said valve being adapted to have its optical characteristics changed when a potential exceeding a predetermined threshold potential is applied across the valve;

an electrically conductive member adapted to be touched in a predetermined manner;

means for series connecting said member and valve;

means, including said series connecting means, normally operative for open circuiting said valve, said means being operative when said member is touched for completing a circuit through said valve with the potential thereacross exceeding said excitation potential, whereby the optical characteristics of said valve are changed; and

means for detecting the change in the optical characteristics of said valve, and for generating an electrical output in response thereto.