1、BRITISH STANDARD BS 4301:1991 Recommendations for Preparation of drawings for optical elements and systemsBS4301:1991 This British Standard, having been prepared under the directionof the Cinematography and Photography Standards PolicyCommittee, was publishedunder the authority of the Standards Boar
2、d and comes into effect on 30August1991 BSI 12-1999 First published April 1968 Second edition April 1982 Third edition August 1991 The following BSI references relate to the work on this standard: Committee reference CPM/17 Draft for comment 90/38757 DC ISBN 0 580 19716 6 Committees responsible for
3、this BritishStandard The preparation of this British Standard was entrusted by the Cinematography and Photography Standards Policy Committee (CPM/-) to Technical Committee CPM/17, upon which the following bodies were represented: Department of Trade and Industry (National Physical Laboratory) Engine
4、ering Equipment and Materials Users Association Federation of Manufacturing Opticians Flat Glass Manufacturers Associations Ministry of Defence Sira Limited Society of British Aerospace Companies Limited Amendments issued since publication Amd. No. Date CommentsBS4301:1991 BSI 12-1999 i Contents Pag
5、e Committees responsible Inside front cover Foreword iii Section 1. Introduction 1 Scope 1 2 References 1 3 Introductory notes 1 4 Definitions 1 Section 2. General recommendations, methods of presentation and definition of materials for optical elements and systems 5 Types of drawing 2 6 Orientation
6、 of drawings 4 7 Methods of representation 4 8 Dimensions and tolerances 7 9 Materials 11 Section 3. Optical elements: strain-birefringence 10 Definitions 11 11 Defect rating code 11 12 Use of defect rating code 11 Section 4. Optical elements: inclusions and digs 13 Description 12 14 Defect rating c
7、ode 12 15 Use of defect rating code 12 Section 5. Optical elements: homogeneity 16 Definition 12 17 Defect rating code 12 18 Use of defect rating code 13 Section 6. Optical elements: form errors 19 Definitions 14 20 Defect rating code 14 21 Total form error (transmitted wave error, cumulative error
8、or effective form error) 15 Section 7. Optical elements: centring errors 22 Definition 15 23 Method of specifying centring error 15 24 Defect rating code 16 Section 8. Optical elements: surface defects 25 Definitions 17 26 Defect rating code 18 27 Use of defect rating code 18 28 Design and use of ca
9、librated line-equivalent width standards (CLEWS) and spot-equivalent standards (CSES) 19 Section 9. Optical elements: surface texture 29 Definitions 19 30 Method of specifying surface texture 20 31 Grey surfaces 20 32 Polished surfaces 20BS4301:1991 ii BSI 12-1999 Page Section 10. Optical elements:
10、surface treatment 33 Description 22 34 Markings 22 35 Reflective coatings 23 36 Anti-reflective coatings 23 37 Paint and other treatments 24 Section 11. Optical subassemblies: joining of optical elements 38 Identification 24 39 Defects in joined graticule elements 24 40 Other defects 24 41 Other joi
11、ning methods 24 42 Centring of subassemblies 24 Figure 1 Optical arrangement drawing 3 Figure 2 Field stop position 5 Figure 3 Pupil position 5 Figure 4 Physical aperture 5 Figure 5 Pupil marking 6 Figure 6 Dimensions of field stops and pupils 6 Figure 7 View showing test region 8 Figure 8 Test regi
12、ons 8 Figure 9 View showing test field within a test region 9 Figure 10 Diameters and tolerances 9 Figure 11 Spherical and plane surfaces 9 Figure 12 Example of geometrical tolerancing for prismatic component 10 Figure 13 Cemented spherical surface 11 Figure 14 Surface form error using BS 308 symbol
13、 14 Figure 15 Surface form error (non-preferred alternative) 15 Figure 16 Drawing presentation of form error tolerances 16 Figure 17 Surface tilt to mounting datum 17 Figure 18 Lens centring error to edged surface 17 Figure 19 Typical viewing arrangement for surface defects 21 Figure 20 Symbols for
14、optical working 21 Figure 21 Example of use of surface texture symbol for grey surface 22 Figure 22 Examples of use of surface texture symbols for polished surfaces 22 Figure 23 Partially reflective coating 23 Figure 24 Anti-reflective coating 24 Figure 25 Painted surface 24 Figure 26 Surface tilt t
15、o mounting datum (assembly) 25 Figure 27 Lens centring error (assembly) 25 Table 1 Summary of defect codes and symbols 4 Table 2 Strain-birefringence defect rating 12 Table 3 Homogeneity defect rating 13 Table 4 LEW threshold and reference letter 18 Table 5 Preferred maximum roughness values 20 Tabl
16、e 6 Symbols and grades for polished surfaces 20 Table 7 Symbols for coatings 23 Publication(s) referred to Inside back coverBS4301:1991 BSI 12-1999 iii Foreword This British Standard has been prepared under the direction of the Cinematography and Photography Standards Policy Committee. It supersedes
17、 BS 4301:1982, which is withdrawn. This standard was first published in1968and was revised in 1982. This second revision has been prepared as a result of a request for improved methods of describing and quantifying surface defects. Technical changes in this edition have therefore been confined to cl
18、auses 14, 15, 26, 27 and 28, together with a minor addition to clause 32. BS 308, particularly Part 3, provides ample scope for the definition of complex shapes on drawings and this standard contains only directions on matters not covered or inadequately covered in BS 308. In particular, and because
19、 of the common practice in the optical industry to use angular measurements when measuring and checking optical elements and subassemblies, this standard introduces the use of angular values and fringes in the tolerance flames. This special need for optical drawings is not covered in BS 308-3, and B
20、S4301should be regarded as a supplement to that standard. The preparation of International Standards on related subjects is not sufficiently advanced to justify delaying the publication of this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users
21、 of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1to26, an inside back cover and a back
22、 cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS4301:1991 BSI 12-1999 1 Section 1. Introduction 1 Scope These recommendations apply to the presentation, on drawings
23、, of design and functional requirements for optical elements and systems. Sections 5, 8 and9include information considered necessary for the correct appreciation and application of the recommendations. The material included is that necessary to provide a standardized method of presenting information
24、 on drawings, and is not intended to impose restrictive practices upon designers. 2 References The titles of the publications referred to in this standard are listed on the inside back cover. 3 Introductory notes 3.1 BS 308 methods should be used unless recommended otherwise in this standard. 3.2 Th
25、e inclusion in these recommendations of the means of indicating various parameters of optical elements or systems does not imply a requirement that such information should be on a drawing. Therefore on a drawing the omission of any parameter should be taken as indicating that there is no requirement
26、. The preferred method, however, relative to the use of defect codes (see Table 1) is to follow the index figure and oblique line by a hyphen (e.g. 5/-) as this signifies that the lack of instruction is deliberate. Additionally, the use of the instruction “(see note)” as an alternative to the hyphen
27、 can be used to indicate the presence of a note giving further information. In this case the note should be numbered to provide easy reference (see 7.5). In some circumstances the individual defect rating of elements is not critical within the context of the performance of the complete assembly or s
28、ubassembly. In such cases there is no reason to insist on the defect rating of each element when assembled being within a stated specification, and it is recommended that the defect rating should be enclosed in brackets, thus: 5/(a b c). This will indicate to the manufacturer of the total system tha
29、t the rating is for guidance only, but should be applied to individual elements being provided as replacements in existing systems. 4 Definitions For the purposes of this standard the definitions given below, and at the beginning of some later sections, apply. NOTEThe definitions given below are of
30、a general nature and are therefore not included in each section. Further definitions are given in the relevant sections. 4.1 element an optical unit that cannot be subdivided into other optical units 4.2 field stop the aperture or any of its images limiting the extent of the object viewed 4.3 pupil
31、the aperture or any of its images limiting the bundle of rays entering the system from an object point at the centre of the field NOTE 1The entrance pupil is the pupil in the object space. NOTE 2The exit pupil is the pupil in the image space. 4.4 optical axis the ray path passing through centres of
32、pupils and field stopsBS4301:1991 2 BSI 12-1999 4.5 test region an optically effective surface or space, or both, that is subject to testing to ascertain defects 4.6 test field the portion of a test region that is effective in the system at any one time Section 2. General recommendations, methods of
33、 presentation and definition of materials for optical elements and systems 5 Types of drawing Three types of drawing may be needed, as indicated in 5.1 to 5.3. 5.1 Optical arrangement. An optical arrangement drawing is only for reference and should show the relative positions of all the elements or
34、subassemblies of a complete optical system and should specify, as appropriate, the following: a) element or subassembly reference part numbers (or parts-list reference numbers); b) separation distances; c) magnification and/or system equivalent focal length; d) magnification between consecutive imag
35、e planes; e) true field of view; f) position and sizes of field stops; g) position and sizes of pupils; h) clear apertures at element or subassembly component surfaces; i) details of light source; j) special notes regarding assembly and test procedures; k) movements required for magnification and fo
36、cus adjustment; l) mounting interface data. An example is shown in Figure 1. 5.2 Optical subassembly. An optical subassembly drawing should give, as appropriate, the following: a) element part numbers (or parts-list reference numbers) and assemblies on which each is used; b) details of cement or oth
37、er method of fixing (see section 7); c) dimensions and tolerances that are additional to those given in the detail drawings; d) equivalent focal length or test data; e) special notes regarding assembly and test procedures.BS4301:1991 BSI 12-1999 3 5.3 Optical detail. An optical detail drawing should
38、 give, as appropriate, the following: a) assembly or subassembly to which the detail applies; b) material specification (see clause 9); c) codes for material defects (see sections 3, 4 and5); d) dimensional data with tolerances (seeclause8): including centring and equivalent focal length; e) surface
39、 texture (see section 9); f) surface treatment (see section 10); g) test regions and test data (see 7.7); h) codes for surface defects (see section 8) and form errors (see section 6). i) Table 1 printed as an explanatory key. All dimensions are in millimetres unless otherwise stated. NOTE 1Total mag
40、nification at infinity focus 6. NOTE 2Eyepiece magnification 10.6. NOTE 3True field of view 7 . NOTE 4Graticule is adjusted laterally to obtain correct line of sight. Figure 1 Optical arrangement drawingBS4301:1991 4 BSI 12-1999 Table 1 Summary of defect codes and symbols 6 Orientation of drawings O
41、rientation of optical arrangement drawings should be such that the ultimate receptor (e.g. the eye, projection screen, photographic plate or photoelectric cell) should appear to be on the right-hand side, unless shown otherwise on the corresponding mechanical assembly drawing. In subassembly and det
42、ail drawings, elements may be oriented with optical axes horizontal or as they appear on the optical arrangement drawing. 7 Methods of representation 7.1 Where there is a particular need to indicate optical axes they should be shown as thin chain double-dash lines, thus: 7.2 Optical materials when s
43、hown in section should use the following representation: Strain birefringence Polished, coarse Inclusions Polished, medium Homogeneity Polished, fine Surface form error Polished, very fine Lens centring error Coating, first surface reflective Surface defects Coating, second surface reflective Rough,
44、 not worked Coating, partial reflective Rough, working optional Coating, anti-reflective Rough, working mandatory Coating, paintBS4301:1991 BSI 12-1999 5 7.3 Field stops and pupils in optical arrangement drawings should be indicated as follows. a) Position of field stop is indicated by a cross (i.e.
45、 ) on the optical axis (see Figure 2). b) Position of pupil is indicated by a short line across the optical axis (see Figure 3). c) Physical apertures should be drawn in thick continuous lines defining position; sizes should be indicated by short cross lines. Other apertures should be drawn in a sim
46、ilar manner, but in thick dashed lines. When required, field stops should be marked FS 1 , FS 2etc., following the path of the incident light (see Figure 4). d) When required, pupils should be marked EP 1 , EP 2 , etc., following the path of the incident light (seeFigure 5). Figure 2 Field stop posi
47、tion Figure 3 Pupil position Figure 4 Physical apertureBS4301:1991 6 BSI 12-1999 e) Dimensions of field stops and pupils should be shown adjacent to the stop or pupil (see Figure 6). 7.4 General notes and notes relative to defect classifications should be always grouped together at one edge of the d
48、rawing. Each separate note should have a number for ease of reference against dimensional or defect classification data on the main part of the drawing. Such notes should refer, when appropriate, to the following: a) magnification(s); b) true field of view; c) equivalent focal length; d) assembly an
49、d testing procedure; e) performance specification; f) detail of light source or principal wavelength or both; g) notes applicable to defect classifications qualified by the instruction: (see note); h) coating description or performance specification (see section 10); i) description of paint or other treatments (see section 10); j) cement or joining specification (see section 7). Figure 5 Pupil marking Figure 6 Dimensions of field stops and pupilsBS4301:1991 BSI 12-1999 7 7.5 In o
