Touch sensitive cathode ray tube

• US 4,689,614 A
• Filed: 12/04/1985
• Issued: 08/25/1987
• Est. Priority Date: 04/04/1984
• Status: Expired due to Fees

• Current Assignee: Syrinx Innovations Limited
• Original Assignee: Synrinx Innovations Limited
• Inventors: Strachan, John S.
• Primary Examiner(s): Curtis, Marshall M.
• Assistant Examiner(s): FATAHI YAR, MAHMOUD
• Application Number:
  US06/810,329
• Time in Patent Office: 629 Days
• Field of Search: 340/365 C, 340/365 A, 340/712, 340/706, 340/707, 315/4, 315/13.11, 315/84.51, 250/213 VT
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0414 using force sensing means to determine a position

Abstract

A cathode ray tube provided on the exterior of its screen with a layer of polymeric piezoelectric material, for example polyvinylidene fluoride. Localized changes in physical stress on the layer, such as by way of localized pressure of heating on the layer, create a charge region which produces alteration of a beam current of an electron beam when the beam scans over the region. This alteration is detected, as by a sensing loop, to produce a data input.

Claims

1. A cathode ray tube comprising:

a screen having an exterior surface;

a transparent layer on said exterior surface, said layer being of polymeric piezoelectric material having the characteric of generating a localized charge at an area of said screen in response to localized changes in physical stress applied to said layer;

detecting means for monitoring a beam current of an electron beam traveling along a beam path, to detect when said electron beam scans over a said area of localized charge.

2. A cathode ray tube according to claim 1, in which said layer is of polyvinylidene fluoride.

3. A cathode ray tube according to claim 1, in which said layer is coated with a transparent conductive layer connected to ground.

4. A cathode ray tube according to claim 2, in which said layer is coated with a transparent conductive layer connected to ground.

5. A cathode ray tube according to claims 1, 2, 3, or 4, in which said detecting means comprises a current sensing loop disposed around said electron beam path.