Particulate spacers for touch sensitive overlay panel applications
US4965421A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 1988 |
| Grant date | Oct 23, 1990 |
| Priority date | — |
| Expiry date | Nov 8, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/252
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Fine particles, of predetermined composition and sized to be within a predetermined size range, are deposited on, and thereafter adhere in random distribution to, one of two adjacent surfaces, serving to keep the surfaces uniformly spaced apart except when an external force causes them to make local contact. The particles are conveniently applied in the form of a spray of a suspension of particles and a fluid carrier material, preferably water with alumina particles, or an aqueous solution of a chloride salt of an alkaline earth metal such as calcium, potassium or sodium when small glass beads are used as the particles. Brown alumina particles (approximately 96% Al.sub.2 O.sub.3) in the size range 3-50 microns, so utilized, are found well suited as parallel surface spacers in optically transparent touch sensitive overlay (TSO) panels. Particle distribution densities in the range 300-1,000 particles per inch are satisfactory for TSO panels, with the higher particle density requiring a higher actuation pressure to be applied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.