Difference between revisions of "Fixed Lens"
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'''2-2-090 | '''2-2-090 | ||
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The rings are contiguous or nearly so. | The rings are contiguous or nearly so. | ||
[[Image: | [[Image:Ch2_Fig16a.jpg|400px|border]] | ||
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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. | ||
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[[Category:Alphabetical Index]] | [[Category:Alphabetical Index]] | ||
[[Category:IALA Dictionary 1970-89 Edition]] | [[Category:IALA Dictionary 1970-89 Edition]] | ||
[[Category:IALA Dictionary 2023 Revision]] | |||
Latest revision as of 02:34, 3 February 2024
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)
