Iec 61747 40 3 2015

IEC 61 747 40 3 Edition 1 0 201 5 01 INTERNATIONAL STANDARD Liquid crystal display devices – Part 40 3 Mechanical testing of display cover glass for mobile devices – Biaxial flexural energy to failure[.]

IEC 61 747- 40- 3

Editio 1.0 2 15-01

Liquid cryst al display devices –

Part 40-3: Mechanical t est ing of display cover glass for mobi e devices – Biaxial

flexural energy t o fai ure (bal drop)

®

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IEC 61 747- 40- 3

Edit io 1.0 2 15-01

Liquid cryst al display devices –

Part 40-3: Mechanical t est ing of display cover glass for mobi e devices – Biax ial

flex ural energy t o fai ure (bal drop)

INT ER NAT IONAL

ELECT R OT ECHNICAL

®

FOREWORD 3

INTRODUCTION 5

1 Sco e 6

2 Normative ref eren es 6

3 Terms an def i ition 6

4 General 6

5 Ap aratu 7

5.1 Testin en ironment an pre-con itionin 7

5.2 Ap aratu overview 7

5.3 Heig t adju tment b am 8

5.4 Sp cimen holder 8

5.5 Armature 9

5.6 Bal rele se mec anism 10 5.7 Heig t adju tment clamp 10 5 8 Bal rele se control er 1

0 5.9 Bal 10 5.10 Base 10 6 Proced re 10 6.1 Safety 1

0 6.1.1 Hazard – Broken glas 10 6.1.2 Hazard – Compres ion d e to movin b l 10 6.2 Sample 10 6.3 In ivid al sp cimen 1

6.4 Complete the re ort 1

7 Calc lation 12 7.1 Bre kin energ 12 7.2 Statistical calc lation 12 8 Re ortin 13 8.1 Inf ormation to b re orted for e c test 13 8.2 Inf ormation to b made avai a le up n req est 13 9 Sp cif i ation 14 Fig re 1 – Ap aratu overview 8

Fig re 2 – Sp cimen holder ( o view) 9

Fig re 3 – Sp cimen holder (side view, cros -section) 9

Fig re 4 – Example Weibul plot 13

INTERNATIONAL ELECTROTECHNICAL COMMISSION

LIQUID CRYSTA L DISPLA Y DEVICES –

Part 40-3: Mechanical testing of display cover glass for mobi e devices –

Biaxial flexural energy to fai ure (bal drop)

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International Stan ard IEC 617 7-4 -3 has b en pre ared by tec nical commit e 1 0:

Electronic display devices

The text of this stan ard is based on the f ol owin doc ments:

Ful inf ormation on the votin for the a proval of this stan ard can b f ou d in the re ort on

votin in icated in the a ove ta le

This publ cation has b en draf ted in ac ordan e with the ISO/IEC Directives, Part 2

A l st of al p rts in the IEC 617 7 series, publ s ed u der the general title Liquid cryst al

display d evic s, can b fou d on the IEC we site

The commit e has decided that the contents of this publ cation wi remain u c an ed u ti

the sta i ty date in icated on the IEC we site u der "ht p:/ we store.iec.c " in the data

related to the sp cif i publ cation At this date, the publ cation wi b

• reconfirmed,

• with rawn,

• re laced by a revised edition, or

A bi n ual version of this publcation may b is ued at a later date

Mo i e electronic devices have b come in re sin ly so histicated an often in lu e display

f or the purp ses of u er interace an viewin Su h display commonly in orp rate a

tran p rent cover glas whic aid in protectin the display again t the introd ction of

damage throu h routine device tran p rt an u e, as wel as oc asional or ac idental mis se

The purp se of this stan ard is to provide mec anical testin proced res f or cover glas es

uti zed in s c a plcation Su h glas es can b stren thened, for example via an ion

-ex han e proces , whic acts to in re se mec anical stren th throu h the introd ction of a

s race compres ive layer

LIQUID CRYSTA L DISPLA Y DEVICES –

Part 40-3: Mechanical testing of display cover glass for mobi e devices –

Biaxial flexural energy to fai ure (bal drop)

This p rt of IEC 617 7-4 is a mec anical p r orman e testin proced re for cover glas

u ed in electronic f lat p nel display in mo i e devices This stan ard is f oc sed on the

me s rement of s rf ace imp ct resistan e via biaxial flex re generated by a b l dro

The f ol owin doc ments, in whole or in p rt, are normatively ref eren ed in this doc ment an

are in isp n a le f or its a pl cation For dated ref eren es, only the edition cited a ples For

u dated referen es, the latest edition of the referen ed doc ment (in lu in an

amen ments) a pl es

IEC 617 7-4 -1, Liquid crystal d ispl ay devic s – Part 4 -1: Mec a ic l test in of d isplay

c v r gl as for mo il e d evic s – Guidel ines

IEC 616 9:2 0 , Weib ll a alysis

3 Terms and def initions

For the purp ses of this doc ment, the f ol owin terms an def i ition a ply

3.1

in ivid al piece of glas to b tested to f ai ure

3.2

s mple

group of sp cimen s arin a common p digre (s c as man f acturin proces an p riod

of prod ction), f or whic faiure statistic can b generated an re orted

3.3

s mple size

n mb r of sp cimen in a sample

3.4

nominal v lue

value a out whic a toleran e ran e is sp cified

This test is statistical in nature A b l is dro p d onto e c of a n mb r of sp cimen in a

sample The energ req ired to bre k e c sp cimen is recorded Statistic that mig t b

sp cified are calc lated an re orted The energ req ired to bre k a given sp cimen is

determined by startin with a minimum dro heig t an then in re sin the dro heig t by a

f i ed in rement for dro s that do not res lt in bre kage

The typical energ req ired to bre k sp cimen wi de en on the sp cimen nominal

dimen ion , len th an width, as wel as thic nes Sample bre kage values s ould only b

comp red when the nominal dimen ion of the samples are the same

The combination of b l mas an dro pin heig t yield the bre kage energ The a p ratu

al ows for a maximum dro heig t of at le st 18 cm A b l mas of 12 g may b adeq ate

f or 5 mm × 5 mm (± ,5 mm) sp cimen with thic nes ran in f rom 0,5 mm to 2,0 mm

Thic er, stron er or larger sp cimen may req ire a larger b l f or a 10 % bre kage by a

dro heig t of 18 cm

Clau e 5 des rib s the a p ratu Clau e 6 des rib s the proced res f or b th the sample as

a whole as wel as f or an in ivid al sp cimen Clau e 7 des rib s the calc lation

To complete the test, some me n of catc in the b l when the b l dro do s not bre k the

sp cimen s ould b provided This could b done by providin the tester with an as istant or

by some a p ratu Pos ible a p ratu o tion are not doc mented in this stan ard

When the b l dro do s not bre k the sp cimen an b u ces, the re ou d heig t may b up

to a proximately 8 % of the original dro heig t an is p ral el to the heig t adju tment

b am When the dro res lts in breakage, the b u ce direction is ran om but the re ou d

heig t is s bstantial y red ced

When bre kage oc urs d e to a fai ure to catc the re ou din b l an a double imp ct

res lts in bre kage, the heig t is recorded, but the sp cimen is tre ted as a late s sp n ion

(se 7.2)

It is as umed that al me s rements are p rormed by p rson el s i ed in the general art of

mec anical pro erty me s rements Furthermore, it s ould b as ured that al eq ipment is

s ita ly cal brated as is k own to s i ed p rson el an that record of the cal bration data

an trace bi ty are ke t

5.1 Te ting e vironme t a d pre-conditioning

The stan ard testin en ironment is sp cified in 617 7-4 -1 Sp cimen s al b stored in

s c an en ironment for at le st f our hours b fore testin

Fig re 1 s ows the overview of the a p ratu

Key

A Heig t a ju tme t b am

B Sp cime h ld r

C Armature

D Bal rele s me h nism

E Heig t a ju tme t clamp

F Bal rele s c ntroler

G Bal (whie dro pin )

H Ba e

Figure 1 – Ap aratus ov rview

5.3 Height a justme t be m

This b am s al b lon enou h to al ow dro s of at le st 18 cm in maximum heig t It is

p rp n ic lar to the testin s rf ace It s al b marked with distan es f om the test s rf ace in

in rements of 5 cm The test s r ace is the to s race of the sp cimen when it is in erted

into the sp cimen holder Dro distan e is the distan e fom the test s race to the b t om of

the b l when it is at ac ed to the b l rele se mec anism

To ac ommodate the p s ibi ty of dif ferent sp cimen thic nes es or sp cimen holder

dimen ion , a cor ection f actor can b u ed to con ert the heig t markin s on the heig t

adju tment b am to the actual dro pin distan es to within ±1 mm b fore the energy

calc lation is completed

5.4 Spe ime hold r

This is made of a rigidized p lymer (s c as p lyox meth lene (POM), hig den ity

p lyeth lene (HDPE), p ly(meth l methacrylate) (PMMA), p ly(meth l acrylate) (PMA) or

p ly arb nate (PC) to minimize damage to sp cimen as they are mou ted into it It is a

s uare or rectan ular f ame that s p orts a sp cimen on a led e of 4 mm to 6 mm, with the

led e s r ou ded by a sp cimen containment b r ier The b r ier dimen ion s al b large

enou h to ac ommodate al sp cimen without bin in The specimen s al b elevated fom

A

B

C

D

E

F

G

H

IEC

the ta le by a distan e that is large enou h that no sp cimen tou hes the ta le d e to

deflection d rin a test

Fig re 2 s ows a to view an Fig re 3 s ows a side view cros -section

NOT Th k y to th leters is pro id din Fig re3

Fig re 2 – Spe ime holder (top view)

Key

A Ba e s ra e

B Sp cime c ntainme t b rier

C L d e

Figure 3 – Spe ime holder (side view, cros -s ction)

The sp cimen holder, b se an /or heig t adju tment b am desig s al provide a me n of

re e ta i ty by placin the sp cimen holder so the b l dro s onto the centre of the

sp cimen Displacement er or f rom the inten ed dro location s al not b gre ter than 2

mm when p r ormin dro s ≤ 1 m in heig t an not gre ter than 3 mm when p rf ormin dro s

> 1 m in heig t Displacement er ors can b as es ed via the u e of a plumb l ne, a plumb

b b an pres ure-in icatin f ilms, or via other me n whic ena le the ac urate q antification

of inten ed vers s actual dro p sition

5.5 Armature

B

C

A

IEC

B

C

A

IEC