9. 9
FUNDAMENTAL STIPULATIONS
All indications apply to the finished product
(except where specified), in mm, at 22°C.
Mercury e-line (546.07nm) default
For preference, light is incident from the left,
axis is horizontal.
If components are hatched, cemented
assemblies to be hatched in alternate
directions
On each drawing add note, near the title:
“Indications in accordance with ISO 10110”
10. 10
AXES
Axis of symmetry, rotation axis, centre line
Optical axis
Exaggerate shifts, if necessary, for clarity
11. 11
RADII OF CURVATURE
Radius leaders can extend to the axis
Tolerances can be expressed numerically
or interferometrically
Flat surface denoted by R, with
tolerance expressed interferometrically
Weak surfaces e.g. R3000 CX (or CC)
Toric surfaces e.g. Rcyl 50
12. 12
SURFACE TEXTURE
A specular surface (“polished”) is denoted by
P, followed by 4 (<3) 3 (3-15) 2 (16-79) 1 (80-
400 defects per 10 mm of length)
Matt (“ground”) is denoted by G, with
maximum r.m.s. roughness denoted by Rq
followed by a value in microns.
G
Rq 2
14. 14
THICKNESS
Tolerances preferably symmetrical.
Overall thickness in brackets.
If the thickness of a sub-assembly has
tighter tolerances than the individual
components, the thickness tolerance of
the sub-assembly is followed by the letter
M, indicating that the parts are to be
matched.
(16,3)
14 ±0,1
16. 16
DIAMETER & TEST AREAS
Tolerances expressed as for mechanical parts
Optical clear diameter, “effective diameter” e.g.
e66.
Test areas shaded, as below - test regions may
be labelled. Test volumes may also be defined
(e.g. Special tolerance for bubbles)
(16,3)
14 ±0,1
68
-0,1
-0,05
e
66
1
2
17. 17
CHAMFERS
A bevel is a functional surface which must be
fully toleranced; a protective chamfer replaces
an edge or corner and must not be drawn. It is
dimensioned as shown (“w”). A dimension
marked “theor” ignores any chamfer.
Inside edges are generally toleranced as
maximum permitted width.
If an edge must remain sharp, use the symbol
“O”
50 ±0,1 theor
O
30°±5°
0,3
0,1
NOTE - Protective chamfers 0,2-0,5
0,3
18. 18
TABULAR DATA
MATERIAL
Name, manufacturer, n refractive index, Abbe number.
0/ Stress birefringence tolerance
1/ Bubbles and inclusions tolerance
2/ Inhomogeneity and striae tolerance
SURFACE
R CX/CC radius e optically effective diameter Protective chamfer
3/ Surface form tolerance
4/ Centring tolerance
5/ Digs, coating imperfections, edge chips
6/ Laser irradiation damage threshold
“To be cemented” if appropriate
19. 19
0: STRESS BIREFRINGENCE
0/A where A = maximum permissible stress
bifringence in nm per cm of optical path length.
A=20 Magnifiers and viewfinders
A=10 Microscopes and photographic lenses
A=5 Astronomical telescopes
A<2 Polarisation instruments, interferometers
OPD = sample path length (cm) x residual stress
(N/mm2)xdifference in photoelastic constants
(10-7 mm2/N)
1/2 x 0,25
0/20
Schott catalogue values for A:
Normal fine annealed <= 10
Normal special annealed <= 6
Precision special annealed <= 4
but BK7 800 mm diam <= 12
and BK7 1000 mm diam <= 20
21. 21
1: BUBBLES AND INCLUSIONS
1/N x A where N = number of maximum size
bubbles allowed, A = area of projected area of
the largest allowable bubble, in mm.
Larger numbers of bubbles are allowed if the
total area does not exceed NxA2 Bubbles
smaller than 0.16A are not counted.
Preferred values of A are 0,1; 0,16; 0,25; 0,4;
and 0,63 and powers of 10 above and below.
Multiples are x2.5 for one grade up, x6.3 for two
grades up, and x16 for three grades up. e.g.
2x2.5=5 bubbles of grade 0,16 or 2x6.3=12 of
grade 0,1 or 2x16=32 of grade 0,063 will satisfy
the example given here.
Not more than 20% of the bubbles (or 2, if N is
less than 10) can be concentrated in less than
5% of the test region.
1/2 x 0,25
0/20
23. 23
2: INHOMOGENEITY AND STRIAE
2/A;B where A = 0 means inhomogeneity <±50.10-6 A =1: 20 A
=2:5 A =3:2 A =4:1 These correspond to roughly to Schott
Normal & H1..H4
B =5 means extremely free of striae (Schott P, NVS), =4 means
striae occupy <1% of test area (Schott N), =3: <2% =2: <5%,
=1:<10%
1/2 x 0,25
0/20
2/1;4
A is class number for inhomogeneity (variation in index of refraction from nominal for
(usually) the melt where the element came from)
B is class for striae (variations in index of refraction inside the element)
2/A;B
24. 24
3: SURFACE FORM
Best fit sphere
Measured surface
Plane surface
SAGITTA
IRREGULARITY
e66
3/A(-) where A = sagitta, maximum departure of the best fit
sphere from plane, in fringes
3/A(B) where B = irregularity, maximum (PV) departure of the
surface from the best fit sphere.
3/A(B/C) where C = rotationally symmetric irregularity,
maximum departure of irregularity from the best fitting aspheric
3/- RMSt <(total) ;RMSi <(irregular); RMSa <(asymmetrical).
“Total surface deviation not to exceed .... ”
547.07 nm - mercury green unless otherwise specified
26. 26
4: CENTRING
14 ±0,1
(16,3)
A
4/2AB
4/ where = angle of surface relative to datum (or
datums) in minutes - e.g. 4/2 AB.
4/ for cemented surfaces, where = relative
angle between surfaces
4/(L), where L = lateral displacement (e.g. for
aspheric)
Decentration = deviation x 0.00029/(n-1)/(1/R1-1/R2)
e.g.
Runout = 2 x decentration: e.g.
0,01 A B
0,02 A B
B
27. 27
5: SURFACE IMPERFECTIONS (I)
5/N x A where N = number of maximum size digs
allowed, A = area of projected area of the
largest allowable dig, in mm (i.e length of side of
square defect). Smaller digs allowed if
cumulative area does not exceed area of NxA.
Defects less than 0,16A are not counted.
...CNxA: Coating blemish limits are preceded by
C, otherwise include in the general count.
...LNxA Long (>2 mm) scratch limits are
preceded by L (N is the number, A is the width in
mm).
...EA Edge chip limits are preceded by E (any
number are permitted provided maximum extent
from the physical edge, excluding any chamfer,
does not exceed A mm).
5/2 x 0,16; L 2 x 0,04; E 0,5
Preferred grades:
0,004 0,0063 0,01 0,016 0,025
and multiples of 10
28. 28
5: SURFACE IMPERFECTIONS (II)
5/TV for transmitted light inspection, 5/RV for
reflected light, where V = 1...5 is visibility class
number (1 is most stringent).
12500 lx against black background. 22500 lx
31250 lx 4625 lx 51310 lx against a variable
background. To standardise, each user must
adjust the background level until the standard
defect (consisting of a chrome evaporated reticle
consisting of two crossed lines, each 15 mm
long, 0,007 mm wide, on 3 mm thick BK7) is only
just visible at 2500 lx. In transmitted light, any
defect (not only a surface defect) visible under
the light conditions specified, counts as a failure.
5/T3
This is an alternative method:
30. 30
Surface Treatment and Coatings
ISO 10110-9
Fill in the box according to ISO 9211 –
– Very important 4-part standard describing coatings specifications
Example would be T = 0.9 for 450 < λ < 750.
Could also refer to a graph indicated elsewhere in the drawing
Could also refer to manufacturer’s coating trade name
Also indicate a surface to be cemented.
30
31. 31
SURFACE TREATMENT & COATING
indicates a functional coating. Symbol is
located outside the element unless under a
protective layer, indicated by a thick chain-
dotted line.
refers to % transmission, to % reflection,
and to % absorption.
All dimensions refer to the finished product,
unless explicitly stated that they refer to the
untreated part.
Beamsplitter coating : =60±5:40±5 after
cementing, 0,04 for = 450 ... 650
Black paint no. 129C5
0,1 mm max. thickness
32. 32
ASPHERIC SURFACES
12
38
0,005 A B
B
2
G
P2
Asphere, toroid, paraboloid indicates a non-
spherical surface. The equation (except for
a cylinder) is given in a note. Unless more
than one diagram is included, the section
given is the y-z plane. The asphere may be
exaggerated for clarity.
Tolerances may be on the sagitta z, on the
slope, or on decentration with a 4/( ) code.
5
2
2
2
2
2
2
/
)
1
(
1
1 i
i
ih
A
R
h
R
h
z
h z z Slope tol R = 56,031
0,0 0,000 0,000 0,3' = -3
5,0 0,219 0,002 0,5' A4 = -0,432 64 E-05
10,0 0,825 0,004 0,5' A6 = -0,976 14 E-08
15,0 1,599 0,006 0,8' A8 = -0,108 52 E-11
19,0 1,934 0,008 1,0' A10 = -0,122 84 E-13
33. 33
OPTICAL LAYOUT DRAWINGS
Shows relative positions of all components, including separations, centring
data, magnification, n.a., field stops and pupils, clear apertures spectral
passband, etc.
A indicates an adjustment made during assembly. V indicates a variation
during use.
A cross (X) on the axis indicates a field stop or image; a vertical line on the
axis indicates a pupil. An image with no physical aperture is marked with
dashed lines:
20
10
FS2
P1
FS1
37. 37
PRACTICAL IMPLEMENTATION
Indications in accordance with ISO 10110. Interpretation of the symbols will be as follows:
MATERIAL: 0/s s = stress birefringence in nm/cm, 10 unless otherwise specified.
1/n x b Bubbles and inclusions: n= number, b=bubble size, side of square with equivalent
area, in mm
2/ i ; s i = inhomogeneity class (default i = 0 is equivalent to index difference ±0.000050
within a part), s = striae class: default s = 0 means <10% of area filled by striae
with optical path difference > 30 nm; s = 4 (<1%), corresponds to Schott grade N.
SURFACE: 3/s(i) Form error: s = spherical error, departure of best fit sphere from nominal shape,
i = irregularity, maximum departure of surface from best fit sphere
s = (Nx +Ny)/2, i = Nx - Ny where Nx Ny are fringe counts across effective aperture
in two orthogonal directions. In most workshops, fringes are HeNe .633 nm.
4/c(d) c = centration error of surface in minutes relative to datum(s) indicated, d=
lateral decentration in mm, only applies to aspheric surfaces.
5/nxd;Lnxw;Cnxc;Ee Digs, scratches, coating defects and edge chips: n=number; d=dig size in mm,
interpreted as for bubble size (above); w=scratch width in mm; c=coating defect
size in mm; e=maximum edge chip extent in from nominal edge in mm.
e.g. 5/1x0.5;L1x0.008 is equivalent to MIL-O-13830A 80-50.
Functional coating: Key to symbols = reflectivity = transmission =
absorption, wavelengths given in nm, default is mercury e (546.1).
Øe Effective (i.e. clear) aperture diameter.
R Radius: CX = convex, CC = concave, P3 = fine polish, G Rq 0.1µm = fine ground.
Suggested note for appending to optical drawings:
