1、BSI Standards PublicationLiquid crystal display devicesPart 40-3: Mechanical testing of display cover glass for mobile devices Biaxial flexural energy to failure (ball drop)BS IEC 61747-40-3:2015National forewordThis British Standard is the UK implementation of IEC 61747-40-3:2015.The UK participati
2、on in its preparation was entrusted to TechnicalCommittee EPL/47, Semiconductors.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions ofa contract. Users are responsible for its corr
3、ect application. The British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 84403 4ICS 31.120Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy C
4、ommittee on 31 January 2015.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS IEC 61747-40-3:2015IEC 61747-40-3 Edition 1.0 2015-01 INTERNATIONAL STANDARD Liquid crystal display devices Part 40-3: Mechanical testing of display cover glass for mobile devices Biaxial f
5、lexural energy to failure (ball drop) INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 31.120 ISBN 978-2-8322-2211-9 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. BS IEC 61747-40-3:2015 2 IEC 6
6、1747-40-3:2015 IEC 2015 CONTENTS FOREWORD . 3 INTRODUCTION . 5 1 Scope 6 2 Normative references 6 3 Terms and definitions 6 4 General . 6 5 Apparatus 7 5.1 Testing environment and pre-conditioning . 7 5.2 Apparatus overview 7 5.3 Height adjustment beam . 8 5.4 Specimen holder . 8 5.5 Armature . 9 5.
7、6 Ball release mechanism 10 5.7 Height adjustment clamp . 10 5.8 Ball release controller . 10 5.9 Ball . 10 5.10 Base . 10 6 Procedure 10 6.1 Safety . 10 6.1.1 Hazard Broken glass. 10 6.1.2 Hazard Compression due to moving ball . 10 6.2 Sample . 10 6.3 Individual specimen 11 6.4 Complete the report
8、11 7 Calculations . 12 7.1 Breaking energy 12 7.2 Statistical calculations 12 8 Reporting. 13 8.1 Information to be reported for each test 13 8.2 Information to be made available upon request . 13 9 Specifications 14 Figure 1 Apparatus overview 8 Figure 2 Specimen holder (top view) 9 Figure 3 Specim
9、en holder (side view, cross-section) 9 Figure 4 Example Weibull plot 13 BS IEC 61747-40-3:2015IEC 61747-40-3:2015 IEC 2015 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ LIQUID CRYSTAL DISPLAY DEVICES Part 40-3: Mechanical testing of display cover glass for mobile devices Biaxial flexural energy to f
10、ailure (ball drop) FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning sta
11、ndardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their prepara
12、tion is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely wit
13、h the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subj
14、ects since each technical committee has representation from all interested IEC National Committees. 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical
15、 content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent p
16、ossible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conf
17、ormity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its dire
18、ctors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arisin
19、g out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is dr
20、awn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61747-40-3 has been prepared by technical committee 110: Electronic display device
21、s. The text of this standard is based on the following documents: CDV Report on voting 110/569/CDV 110/609A/RVC Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the
22、 ISO/IEC Directives, Part 2. BS IEC 61747-40-3:2015 4 IEC 61747-40-3:2015 IEC 2015 A list of all parts in the IEC 61747 series, published under the general title Liquid crystal display devices, can be found on the IEC website. The committee has decided that the contents of this publication will rema
23、in unchanged until the stability date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. A bilingual version of this publication may be i
24、ssued at a later date. BS IEC 61747-40-3:2015IEC 61747-40-3:2015 IEC 2015 5 INTRODUCTION Mobile electronic devices have become increasingly sophisticated and often include displays for the purposes of user interface and viewing. Such displays commonly incorporate a transparent cover glass which aids
25、 in protecting the display against the introduction of damage through routine device transport and use, as well as occasional or accidental misuse. The purpose of this standard is to provide mechanical testing procedures for cover glasses utilized in such applications. Such glasses can be strengthen
26、ed, for example via an ion-exchange process, which acts to increase mechanical strength through the introduction of a surface compressive layer. BS IEC 61747-40-3:2015 6 IEC 61747-40-3:2015 IEC 2015 LIQUID CRYSTAL DISPLAY DEVICES Part 40-3: Mechanical testing of display cover glass for mobile device
27、s Biaxial flexural energy to failure (ball drop) 1 Scope This part of IEC 61747-40 is a mechanical performance testing procedure for cover glass used in electronic flat panel displays in mobile devices. This standard is focused on the measurement of surface impact resistance via biaxial flexure gene
28、rated by a ball drop. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced documen
29、t (including any amendments) applies. IEC 61747-40-1, Liquid crystal display devices Part 40-1: Mechanical testing of display cover glass for mobile devices Guidelines IEC 61649:2008, Weibull analysis 3 Terms and definitions For the purposes of this document, the following terms and definitions appl
30、y. 3.1 specimen individual piece of glass to be tested to failure 3.2 sample group of specimens sharing a common pedigree (such as manufacturing process and period of production), for which failure statistics can be generated and reported 3.3 sample size number of specimens in a sample 3.4 nominal v
31、alue value about which a tolerance range is specified 4 General This test is statistical in nature. A ball is dropped onto each of a number of specimens in a sample. The energy required to break each specimen is recorded. Statistics that might be specified are calculated and reported. The energy req
32、uired to break a given specimen is determined by starting with a minimum drop height and then increasing the drop height by a fixed increment for drops that do not result in breakage. BS IEC 61747-40-3:2015IEC 61747-40-3:2015 IEC 2015 7 The typical energy required to break specimens will depend on t
33、he specimen nominal dimensions, length and width, as well as thickness. Sample breakage values should only be compared when the nominal dimensions of the samples are the same. The combination of ball mass and dropping height yield the breakage energy. The apparatus allows for a maximum drop height o
34、f at least 180 cm. A ball mass of 128 g may be adequate for 50 mm 50 mm (0,5 mm) specimens with thickness ranging from 0,55 mm to 2,0 mm. Thicker, stronger or larger specimens may require a larger ball for a 100 % breakage by a drop height of 180 cm. Clause 5 describes the apparatus. Clause 6 descri
35、bes the procedures for both the sample as a whole as well as for an individual specimen. Clause 7 describes the calculations. To complete the test, some means of catching the ball when the ball drop does not break the specimen should be provided. This could be done by providing the tester with an as
36、sistant or by some apparatus. Possible apparatus options are not documented in this standard. When the ball drop does not break the specimen and bounces, the rebound height may be up to approximately 80 % of the original drop height and is parallel to the height adjustment beam. When the drop result
37、s in breakage, the bounce direction is random but the rebound height is substantially reduced. When breakage occurs due to a failure to catch the rebounding ball and a double impact results in breakage, the height is recorded, but the specimen is treated as a late suspension (see 7.2). It is assumed
38、 that all measurements are performed by personnel skilled in the general art of mechanical property measurements. Furthermore, it should be assured that all equipment is suitably calibrated as is known to skilled personnel and that records of the calibration data and traceability are kept. 5 Apparat
39、us 5.1 Testing environment and pre-conditioning The standard testing environment is specified in 61747-40-1. Specimens shall be stored in such an environment for at least four hours before testing. 5.2 Apparatus overview Figure 1 shows the overview of the apparatus. BS IEC 61747-40-3:2015 8 IEC 6174
40、7-40-3:2015 IEC 2015 Key A Height adjustment beam B Specimen holder C Armature D Ball release mechanism E Height adjustment clamp F Ball release controller G Ball (while dropping) H Base Figure 1 Apparatus overview 5.3 Height adjustment beam This beam shall be long enough to allow drops of at least
41、180 cm in maximum height. It is perpendicular to the testing surface. It shall be marked with distances from the test surface in increments of 5 cm. The test surface is the top surface of the specimen when it is inserted into the specimen holder. Drop distance is the distance from the test surface t
42、o the bottom of the ball when it is attached to the ball release mechanism. To accommodate the possibility of different specimen thicknesses or specimen holder dimensions, a correction factor can be used to convert the height markings on the height adjustment beam to the actual dropping distances to
43、 within 1 mm before the energy calculation is completed. 5.4 Specimen holder This is made of a rigidized polymer (such as polyoxymethylene (POM), high density polyethylene (HDPE), poly(methyl methacrylate) (PMMA), poly(methyl acrylate) (PMA) or polycarbonate (PC) to minimize damage to specimens as t
44、hey are mounted into it. It is a square or rectangular frame that supports a specimen on a ledge of 4 mm to 6 mm, with the ledge surrounded by a specimen containment barrier. The barrier dimension shall be large enough to accommodate all specimens without binding. The specimen shall be elevated from
45、 A B C D E F G H IEC BS IEC 61747-40-3:2015IEC 61747-40-3:2015 IEC 2015 9 the table by a distance that is large enough that no specimen touches the table due to deflection during a test. Figure 2 shows a top view and Figure 3 shows a side view cross-section. NOTE The key to the letters is provided i
46、n Figure 3. Figure 2 Specimen holder (top view) Key A Base surface B Specimen containment barrier C Ledge Figure 3 Specimen holder (side view, cross-section) The specimen holder, base and/or height adjustment beam design shall provide a means of repeatability by placing the specimen holder so the ba
47、ll drops onto the centre of the specimens. Displacement error from the intended drop location shall not be greater than 2 mm when performing drops 1 m in height and not greater than 3 mm when performing drops 1 m in height. Displacement errors can be assessed via the use of a plumb line, a plumb bob
48、 and pressure-indicating films, or via other means which enable the accurate quantification of intended versus actual drop positions. 5.5 Armature This connects the ball release mechanism to the height adjustment beam. It shall be perpendicular to the height adjustment beam. B C A IEC B C A IEC BS I
49、EC 61747-40-3:2015 10 IEC 61747-40-3:2015 IEC 2015 5.6 Ball release mechanism The ball holding and release mechanism shall either be electromagnetic or vacuum-assisted. This ensures free gravitational acceleration of the ball upon release. Tethering or the use of a guide tube is not an acceptable means of ball release and/or guidance. 5.7 Height adjustment clamp This holds the armature at a height that is indicated by the height adjustment beam while a ball is set and
