IEC 63251:2023

IEC 63251 ®
Edition 1.0 2023-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Test method for mechanical properties of flexible opto-electric circuit boards
under thermal stress
Méthode d’essai des propriétés mécaniques des circuits optoélectriques
souples sous contrainte thermique

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IEC 63251 ®
Edition 1.0 2023-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Test method for mechanical properties of flexible opto-electric circuit boards

under thermal stress
Méthode d’essai des propriétés mécaniques des circuits optoélectriques

souples sous contrainte thermique

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.180  ISBN 978-2-8322-7750-8

– 2 – IEC 63251:2023 © IEC 2023
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Test method . 7
4.1 General . 7
4.2 Test sample . 7
4.3 Test process . 8
4.3.1 General description of the test . 8
4.3.2 Preconditioning . 9
4.3.3 Test . 9
4.3.4 Recovery . 9
4.3.5 Final measurements . 10
5 Report . 10
Annex A (informative)  Example of optical bending loss test results with general glass
optic fibres . 11
Annex B (informative) Example of preparation method of O-E circuit test samples
(optic fibre type) . 12
B.1 General . 12
B.2 Manufacturing processes of the FOECBs with optic fibres (POF, GOF) . 12
B.3 Manufacturing processes of the FOECBs with optical polymer waveguides . 13
B.4 Characteristics of the optic fibres . 14
Annex C (informative) Example of reflow assembly simulation test results . 15
C.1 General . 15
C.2 Results of reflow assembly simulation test for a LED chip mounted FOECB
with GOF . 15
C.3 Results of reflow assembly simulation test for a transparent FOECB with
GOF for display applications . 16
C.4 Results of reflow assembly simulation test for a polyimide (PI) based FOECB
with GOF . 16
C.5 Results of reflow assembly simulation test for a polymer-based FOECB . 17
Annex D (informative) Example of thermal shock endurance test results . 18
D.1 General . 18
D.2 Results of thermal shock endurance test for an FOECB with GOF . 18
Annex E (informative) Example of humidity storage test results . 19
E.1 General . 19
E.2 Results of humidity storage test for an FOECB with GOF . 19
E.3 Results of humidity storage test for an FOECB with POF . 19
Bibliography . 21

Figure 1 – Schematic diagram of FOECB (top view) . 7
Figure 2 – Schematic diagrams of the FOECB test samples of fibre type . 8
Figure 3 – Schematic diagram of the FOECB test samples of fibre type . 8
Figure A.1 – Bending loss test setup . 11
Figure A.2 – Optical loss versus bending diameter . 11
Figure B.1 – Arrayed structure of the FOECB test samples formed on one sheet . 12

Figure B.2 – Fabrication of the optic circuits with optic fibres . 13
Figure B.3 – Fabrication of the optic circuits with optic polymer waveguide via the
photo-etching method . 13
Figure C.1 – LED chip mounted FOECB. 15
Figure C.2 – Appearance of a LED chip mounted FOECB after the reflow assembly

simulation test . 15
Figure C.3 – Appearance of a transparent FOECB with GOFs after the reflow assembly
simulation test . 16
Figure C.4 – Appearance of a PI based FOECB with GOF after the reflow assembly
simulation test . 16
Figure C.5 – Appearance of a polymer-based FOECB after the reflow assembly

simulation test . 17
Figure D.1 – Appearance of an FOECB with GOF after the thermal shock test . 18
Figure E.1 – Appearance of an FOECB with GOF after the humidity storage test . 19
Figure E.2 – Appearance of an FOECB with POF after the humidity storage test . 20

Table 1 – Thermal endurance test class for FOECB . 9

– 4 – IEC 63251:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TEST METHOD FOR MECHANICAL PROPERTIES OF FLEXIBLE
OPTO-ELECTRIC CIRCUIT BOARDS UNDER THERMAL STRESS

FOREWORD
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