Retro-reflective film
Abstract
Abstract Legend containing substantially transparent retro-reflective sheet materials and articles to which the sheet material has been applied, the sheet material having both retro-reflective legend areas and retro-reflective background areas which are substantially indistinguishable under ordinary diffuse light viewing conditions but are clearly distinguishable under retroreflective viewing conditions inasmuch as either the background or the legend is a more efficient retro-reflector. The sheet material includes a monolayer of glass microspheres of at least 1.8 refractive index having a partially light-transmissive mirror in optical connection with the rear surfaces of the beads, the retro-reflective efficiency differing in the legend and background areas. The sheet material may have a pressuresensitive or other adhesive on the rear surface thereof.
Inventors
- 👤 C Sevelin
- 👤 P Palmquist
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |