Optical refraction testing instrument
USD244483S · kind S · design
4Cited by
5References
1Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1975 |
| Grant date | May 24, 1977 |
| Priority date | — |
| Expiry date | May 24, 1980 |
Classification
- Technology area (CPC —)General
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.