Difference between revisions of "Fixed Lens"
Jump to navigation
Jump to search
| Line 7: | Line 7: | ||
The rings are contiguous or nearly so. | The rings are contiguous or nearly so. | ||
[[Image:Ch2_Fig16a.jpg|400px]] | [[Image:Ch2_Fig16a.jpg|400px|border]] | ||
[[Image:Ch2_Fig16b.jpg|400px]] | [[Image:Ch2_Fig16b.jpg|400px|border]] | ||
Note 1: A fixed lens need not extend through 360 degrees, but may be limited to a sector. | Note 1: A fixed lens need not extend through 360 degrees, but may be limited to a sector. | ||
Revision as of 09:54, 1 March 2009
2-2-090
A lens (in sense 2 of 2-2-010) made up of a belt of lenticular section and a series of rings of prismatic section above and below it.
The axes of revolution of the belt and rings form the same vertical straight line.
The rings are contiguous or nearly so.
Note 1: A fixed lens need not extend through 360 degrees, but may be limited to a sector.
Note 2: The light issuing from a fixed lens is in the form of a fan beam (2-1-090).
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
