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1、BRITISH STANDARD BS EN ISO 10938:1998 Ophthalmic instruments Chart projectors The European Standard EN ISO 10938:1998 has the status of a British Standard ICS 11.040.70 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 10938:1998 Thi
2、s British Standard, having been prepared under the direction of the Health and Environment Sector Board, was published under the authority of the Standards Board and comes into effect on 15 July 1998 BSI 04-1999 ISBN 0 580 29902 3 National foreword This British Standard is the English language versi
3、on of EN ISO 10938:1998. It is identical with ISO 10938:1998. The UK participation in its preparation was entrusted by Technical Committee CH/78, Ophthalmic optics, to Subcommittee CH/78/6, Ophthalmic instruments, which has the responsibility to: aid enquirers to understand the text; present to the
4、responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtain
5、ed on request to its secretary. Cross-references Attention is drawn to the fact that CEN and CENELEC standards normally include an annex which lists normative references to international publications with their corresponding European publications. The British Standards which implement these internat
6、ional or European publications may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions
7、 of a contract. Users 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 and ii, the EN ISO title page
8、, page 2, the ISO title page, page ii, pages 1 and 2, an inside back cover and a back 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. Amendments issued since publication Amd.
9、 No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 10938:1998 BSI 04-1999i Contents Page National forewordInside front cover Foreword2 Forewordii Text of ISO 109381 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov
10、15 12:54:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 10938 May 1998 ICS 11.040.70 Descriptors: See ISO document English versi
11、on Ophthalmic instruments Chart projectors (ISO 10938:1998) Instruments ophtalmiques Projecteurs doptotypes (ISO 10938:1998) Ophthalmische Instrumente Sehzeichenprojektoren (ISO 10938:1998) This European Standard was approved by CEN on 9 March 1998. CEN members are bound to comply with the CEN/CENEL
12、EC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CE
13、N member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN m
14、embers are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Norm
15、alisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 10938:1998 E Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42
16、 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 10938:1998 BSI 04-1999 2 Foreword The text of the International Standard ISO 10938:1998 has been prepared by Technical Committee ISO/TC 172 “Optics and optical instruments” in collaboration with Technical Committee CEN/TC 170 “Ophthalmic optics”, th
17、e secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 1998, and conflicting national standards shall be withdrawn at the latest by November 1998. Accordin
18、g to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, S
19、pain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard ISO 10938:1998 was approved by CEN as a European Standard without any modification. NOTENormative references to International Standards are listed in Annex ZA (normative). Contents Page Forewo
20、rd2 1Scope1 2Normative references1 3Requirements1 4Test methods1 5Accompanying documents1 6Marking2 Annex ZA (normative) Normative references to international publications with their corresponding European publicationsInside back cover Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42
21、GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 10938:1998 ii BSI 04-1999 Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bod
22、ies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organization
23、s, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulate
24、d to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 10938 was prepared by Techncial Committee ISO/TC 172, Optics and optical instruments, Subcommittee SC 7, Ophthalmic optics an
25、d instruments. Descriptors: Optics, optical equipment, ophthalmic equipment, test equipment, chart projectors, specifications, optical properties, tests, type testing (tests), performance tests, marking, instructions. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42 GMT+00:00 2006, Un
26、controlled Copy, (c) BSI EN ISO 10938:1998 BSI 04-19991 1 Scope This International Standard, together with ISO 15004, specifies minimum requirements and test methods for chart projector systems, including an optical projector and a screen, for the projection of targets used for the determination of
27、visual acuity, the refractive status and the binocular functions of the human eye. This International Standard takes precedence over ISO 15004, if differences exist. 2 Normative references The following standards contain provision which, through reference in this text, constitute provision of this I
28、nternational Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encourage to investigate the possibility of applying the most recent editions of the standards indicated bel
29、ow. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 8596:1994, Ophthalmic optics Visual acuity testing Standard optotype and its presentation. ISO 8597:1994, Optics and optical instruments Visual acuity testing Method of correlating optotypes. ISO 15004:1997
30、, Ophthalmic instruments Fundamental requirements and test methods. IEC 60601-1:1988, Medical electrical equipment Part 1: General requirements for safety. 3 Requirements 3.1 General The chart projector shall conform to the requirements specified in ISO 15004. 3.2 Functional requirements The chart p
31、rojector shall conform to the requirements specified in 3.2.1 to 3.2.5. NOTEVerification of these requirements is described in clause 4. 3.2.1 Optotypes If designed to be used for certification purposes, the chart projector shall be equipped either with the standard optotype according to ISO 8596 in
32、 the grades specified therein, or with optotypes which are correlated to the standard optotype by the method described in ISO 8597. 3.2.2 Test area and positioning of optotypes If designed to be used for certification purposes, the target of the chart projector system shall comply with the requireme
33、nts of clause 5 and 6.1 of ISO 8596:1994. NOTEIt is recommended that there be at least 5 presentations (see 6.2 of ISO 8596:1994) of each optotype size. 3.2.3 Resolving power When tested as described in 4.2, the chart projector shall conform to the following requirements: The minimum resolution on t
34、he screen (expressed in lines per millimetre) shall be 4/V times the line separation corresponding to the limb width on the smallest optotype which the system is designed to project, where V is the decimal acuity grade of the smallest optotype (see ISO 8596). 3.2.4 Luminance and contrast When tested
35、 as described in 4.2, the chart projector shall conform to the following requirements: The luminance and contrast of the projected chart shall comply with ISO 8596. The luminance of the background surrounding the optotype shall be between 80 cd/m2 and 320 cd/m2. NOTEThe recommended luminance is 200
36、cd/m2. The luminance of the background within 2 character diameters of the optotype shall not vary by more than 30 %. Across the entire area of the projected field it shall not vary by more than 50 %. Screens which are suitable for use with the projector shall be specified by the manufacturer. 3.2.5
37、 Projection range The projection range shall be 2,9 m to 6,1 m. 4 Test methods 4.1 General All tests described in this International Standard are type tests. Measuring devices shall have an accuracy better than 10 % of the smallest value to be determined. 4.2 Resolving power The smallest projected o
38、ptotype shall be observed at of the designed viewing distance an of shall not differ noticeably in contrast and contour from larger optotypes. The observer shall have a decimal visual acuity at least equal to 1,0. 5 Accompanying documents The chart projector shall be accompanied by documents contain
39、ing instructions for use. In particular, this information shall contain: a) name and address of the manufacturer; b) specification of projection screen; 1 3 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 10938:1998 2 BSI 04-1999 c) i
40、f appropriate, a statement that the chart projector contains standard optotypes in accordance with ISO 8596 and/or correlated optotypes in accordance with ISO 8597; d) where appropriate, a statement that the chart projector in its original packaging conforms to the transport conditions as specified
41、in 5.3 of ISO 15004:1997; e) any additional documents as specified in 6.8 of IEC 60601-1:1988. 6 Marking The chart projector shall be permanently marked with at least the following information: a) name of manufacturer or supplier; b) name and model of chart projector; c) marking as required by IEC 6
42、0601-1; d) a reference to this International Standard (ISO 10938), if the manufacturer or supplier claims compliance with it. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 10938:1998 BSI 04-1999 Annex ZA (normative) Normative refere
43、nces to international publications with their corresponding European publications This European Standard incorporates by dated or undated references, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereaft
44、er. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. PublicationYearTitleENYear ISO 8596199
45、4Ophthalmic optics Visual acuity testing Standard optotype and its presentation EN ISO 85961996 ISO 85971994Optics and optical instruments Visual acuity testing Method of correlating optotypes EN ISO 85971996 ISO 150041997Ophthalmic instruments Fundamental requirements and test methods EN ISO 150041
46、997 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 15 12:54:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 10938:1998 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents
47、 the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to
48、 improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: 020 8996 9000.
49、Fax: 020 8996 7400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel: 020 8996 9001. Fax: 020 8996 7001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested. Information on s