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Annex No.2 Contract No. 28/OG-99 Specification for Apochromatic Lenses 1. Optical image quality
For systems of diameter up to 152mm
- Wave front error RMS is no more than 0.035 of wave-length at 532 nm. Wave front error p.t.v. is no more than 0.24 of wavelength at 532 nm.
For systems of more than 152mm up to 254mm diameter
- Wave front error RMS is no more than 0.033 of wave-length at 532 nm. Wave front error p.t.v. is no more than 0.166 of wave-length at 532 nm. 2. Dimensional parameters
Dimensions are to be clarified and coordinated finally on the stage of design documentation preparation. 3. Optical component surface finish
For systems of up to 105mm in diameter - IV class according to 11141-84. For systems of more than 105mm up to 152mm in diameter - V class according to 11141-84. Dimensions of scratches and points shall not exceed the following values:
Surface finish class Scratches Points Accumulation of defects Width,not more, mm Total length, not more, mm Diameter no more,mm Quantity, no more Diamet Surface finish
class | Scratches | Points | Accumulation of defects | | Width, not more, mm | Total length, mm, not more | ? no more, mm | Quantity, no more | ? of a limited area, mm | Total area of scratches and points, no more, square mm | IV | 0.02 | 2 clear aperture | 0.3 | 0.5 clear aperture | 5 | 0.1 | V | 0.04 | | 0.5 | | 10 | 0.4 |
The total scratch length and the point quantity that are close on width and diame.
Surface finish class | Scratches | Points | | Width, mm | Total length, mm, not more | ? , mm | Quantity, no more | IV | 0.01 to 0.02 inclusively | 1 clear aperture | 0.10 to 0.30 inclusively | 0.2 clear aperture | V | 0.02 to 0.04 inclusively | | 0.30 to 0.50 inclusively | |
Scratches and points with the following dimensions are disregarded:
| | Scratch width, not more, mm | Scratch width, not more, mm | | IV | 0.004 | 0.01 | | V | 0.006 | 0.02 |
For lenses of more than 152mm up to 254 mm in diameter the following surface finish requirement shall be ensured:
Scratches and points with the following dimensions are disregarded:
Scratch width, not more, mm | Point ? , not more, mm | 0.008 | 0.04 |
Dimensions of scratches and points shall not exceed the following values:
| Scratches | Points | Accumulation of defects | | Width,Not more, mm | 0.06 | Width,Not more, mm | Quantity, no more | ? of a limited area, mm | Total area of scratches and points, no more, square mm | | 0.06 | 2 clear apertures | 0.7 | 0.5 clear aperture | 25 | 3 |
The total scratch length and the point quantity that are close on width and diameter to the maximum permissible shall not exceed the following values:
Scratches | Points | Width, mm | Total length, mm, not more | Diameter, mm | Quantity, no more | 0.04 to 0.06 inclusively | 1 clear aperture | 0.50 to 0.70 inclusively | 0.2 clear aperture |
Delivery of lenses with scratches exceeding the values above shall be allowed only with consent of the customer. 4. Anti-reflection coating requirements
With consent of the customer non-uniformity of coating interference coloration, which doesn't degrade characteristics of coating optical parameters and doesn't touch output characteristics of a lens, is permissible on anti-reflection surfaces of optical elements. 5. Bubbles and inclusions requirements
Permissible dimensions of bubbles and inclusions:
For systems of diameter up to 152mm
In lens material bubbles and inclusions of no more than 0.3mm in size are allowable , and a number of bubbles of diameter 0.03mm to 0.3mm in each lens shall not exceed 3 pieces.
For systems of more than 152mm up to 254mm diameter
Number of bubbles and inclusions of size up to 0.3mm - not more than 20 pieces. - up to 0.5mm - not more than 3 pieces. Bubbles and inclusions in material exceeding the requirements above shall be coordinated on the stage of optical blanks selection
for the manufacturing of each lens.
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