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Background Statement for SEMI Draft Document 5948
NEW STANDARD: GUIDE FOR MECHANICAL STRESS TEST METHODS IN THE MEASUREMENT OF GAS BARRIER PERFORMANCE FOR FLEXIBLE DISPLAY COMPONENTS AND DEVICES UNDER A NORMAL USAGE CONDITION
Notice: This background statement is not part of the balloted item. It is provided solely to assist the recipient in reaching an informed decision based on the rationale of the activity that preceded the creation of this document.
Notice: Recipients of this Document are invited to submit, with their comments, notification of any relevant patented technology or copyrighted items of which they are aware and to provide supporting documentation. In this context, “patented technology” is defined as technology for which a patent has issued or has been applied for. In the latter case, only publicly available information on the contents of the patent application is to be provided.
Background Statement:
Flexible displays, which is thin and flexible, shock-resistant, and not limited by the occasion or space, will become the top choice of consumer electronic products. Gas barrier is one of important preservation components for flexible display devices. Therefore, a suitable guide of standardized mechanical stress testing methods in the measurement of gas barrier performance should be proposed, e.g. measuring water vapor and oxygen transmission rate for flexible display components or devices under a normal usage condition.
Review and Adjudication Information
Task Force Review / Committee AdjudicationGroup: / Flexible Display Task Force / Taiwan FPD Metrology Committee
Date: / February 16, 2017 / April 20, 2017
Time & Timezone: / 14:00~15:30 (UTC+08:00) Taipei / 15:00~16:30 (UTC+08:00) Taipei
Location: / Rm. 223, Bldg. 16,
No. 321, Sec. 2, Kuangfu Rd. / Rm. 223, Bldg. 16,
No. 321, Sec. 2, Kuangfu Rd.
City, State/Country: / Hsinchu, Taiwan, R.O.C. / Hsinchu, Taiwan, R.O.C.
Leader(s): / Sheng-Po Wang, / Tzeng-Yow Lin,
Jia-Ming Liu,
Standards Staff: / Dean Chang, / Dean Chang,
This meeting’s details are subject to change, and additional review sessions may be scheduled if necessary. Contact Standards staff for confirmation.
Telephone and web information will be distributed to interested parties as the meeting date approaches. If you will not be able to attend these meetings in person but would like to participate by telephone/web, please contact Standards staff. Check www.semi.org/standards on calendar of event for the latest meeting schedule.
If you need further assistance, or have questions, please do not hesitate to contact the Flexible Display Task Force:
Sheng-Po Wang,
SEMI Draft Document 5948
NEW STANDARD: GUIDE FOR MECHANICAL STRESS TEST METHODS IN THE MEASUREMENT OF GAS BARRIER PERFORMANCE FOR FLEXIBLE DISPLAY COMPONENTS AND DEVICES UNDER A NORMAL USAGE CONDITION
1 Purpose
Flexible displays, which is thin and flexible, shock-resistant, and not limited by the occasion or space, will become the top choice of consumer electronic products. However, environment resistant and reliability are most critical issues for flexible displays. Gas barrier is one of important preservation components for flexible display devices. Therefore, a suitable guide of standardized mechanical stress testing methods in the measurement of gas barrier performance should be proposed, e.g. measuring water vapor and oxygen transmission rate for flexible display components or devices under a normal usage condition.
2 Scope
2.1 Standardize the testing methods of gas barrier films, including mechanical test methods including bending, torsion, rolling, tension, shocking, and quasi-static strength, for evaluating water-vapor-transmission-rate and Oxygen transmission rate performance of flexible display components or devices under a normal using condition.
NOTICE: This standard does not purport to address safety issues, if any, associated with its use. It is the responsibility of the users of this standard to establish appropriate safety and health practices and determine the applicability of regulatory or other limitations prior to use.
3 Limitations
3.1 This standard is applicable to process of reliability test for flexible display components or devices.
4 Referenced Standards and Documents
4.1 The following referenced standards are indispensable for the application of this standard. For standards with explicit dates, only the edition cited applies. For undated standards, the latest edition of the referenced standard (including any amendments) applies.
4.1.1 IEC 61747-5:1998, Liquid crystal and solid-state display devices – Part 5: Environmental, endurance and mechanical test methods.
4.1.2 IEC 62341-5:2009, Reliability of organic light emitting diode (OLED) displays – Part 5: Environmental testing methods.
4.1.3 ASTM 1249-06 Standard test method for Water Vapor Transmission Rate through plastic film and sheeting using a modulated infrared sensor.
4.1.4 IEC 62715: Flexible display devices – Part 6-1: Mechanical stress test methods.
4.1.5 IEC 62715: Flexible display devices – Part 6-2: Environmental testing methods.
NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions.
5 Terminology
5.1 Water Vapor Transmission Rate (WVTR) —Water vapor and oxygen transmission rate, which is an index of the passage of water vapor through a substance.
5.2 Mechanical Test — Test methods to evaluate the mechanical stability of flexible components or devices.
5.3 Gas Barrier — A single layer or multi-film layers of passivation function that hinders contaminants in vapor or gaseous forms from transmitting into the active device area.
5.4 Substrate —A layer on which the electric components is deposited.
5.5 Coating layer — The layers that are deposited on base film by wet process and/or dry process. They generally provide high gas/water barrier, good adhesion between base film and other layer, a smooth surface, a hard surface, and a resistance against chemicals respectively. The layer may have several properties above.
6 Mechanical Test
6.1 General
6.1.1 The purpose of mechanical test is to simulate usage scenarios of the product. Therefore, the testing methods must include at least one of the situations that mostly happen when the product is used. Also, environmental setting should include different usage conditions. There are several mechanical test methods defined in IEC 61747-5:1998, Liquid crystal and solid-state display devices – Part 5: Environmental, endurance and mechanical test methods. Three typical test methods were suggested in this standard, including bending test, folding test and rolling test as well.
6.2 Static Bending Test
6.2.1 Static bending test shall be performed in a period of time such as 10 hours. The body of display should firmly adhere to the surface of test device during the test where the test device should have a part of sound shape with a certain radius as shown in Figure 1.
Figure 1Apparatus for static bending test
6.3 Dynamic Bending Test
6.3.1 Dynamic bending test shall be performed repeatedly. The apparatus includes holders to fix the two ends of the test sample. The bending radius is defined with the distance and direction of the holders. The number of bending motions, motion speed and bending radius shall be well defined and recorded. The cyclic bending test equipment includes the clamp to hold a bending test sample, the moving part to shuttle, and control system which regulates cyclic bending number, moving distance, and moving speed while testing as shown in Figure 2.
Figure 2Apparatus for bending test
6.4 Folding Test
6.4.1 The purpose of folding test is to simulate the foldable display application products and verify the reliability of flexible components after large number of times of folding. Therefore the test shall be performed repeatedly. The apparatus includes holders to fix the two ends of the test sample as shown in Figure 3. The bending radius is defined with the distance of the holders. The number of bending motions, motion speed and folding radius shall be well defined and recorded.
Figure 3Apparatus for folding test
6.5 Rolling Test
6.5.1 The rollable device is one of the future product forms for flexible displays. The purpose of rolling test is to simulate the rollable display application products and verify the reliability of flexible components after rolling and releasing motions for large number of times. Therefore the test shall be performed repeatedly. The apparatus includes holders to fix the two ends of the test sample as shown in Figure 4.
Figure 4Apparatus for rolling test
7 WVTR Evaluation
7.1 WVTR test could refer to ASTM 1249-06 Standard test method for Water Vapor Transmission Rate through plastic film and sheeting using a modulated infrared sensor. The test sample is a substrate based on barrier layer without devices as shown in Figure 5. Barrier layer (A) is a single layer or multi-film layers of passivation function that hinders contaminants in vapor or gaseous forms from transmitting into the active device area. Substrate (B) should be with flexibility which barrier layer will be deposited onto.
Figure 5Definition of the sample structure for WVTR measurements
8 Calibration and Standardization
8.1 The LMD used for WVTR measurements and mechanical test apparatus shall be calibrated and traced to the accredited laboratory.
9 Procedures
9.1 WVTR initial measurement
9.1.1 WVTR test should be tested using well-calibrated WVTR test equipment before mechanical test.
9.2 Setup the environmental condition
9.2.1 The environmental condition must be maintained as casual usage condition. A standard atmospheric condition shall be a temperature between 20oC and 25oC, related humidity between 50% ± 20%.
9.3 Mechanical test
9.3.1 Static Bending Test
9.3.1.1 Attach the test sample on the test apparatus, the static bending radius and the duration should be setup and maintained to a steady condition. The test sample must be contained under the defined environmental condition during the whole mechanical test procedures. Table 1 lists an exemplary test condition as follows.
Table 1 Test conditions of the static bending test
Parameter / Value / Unitbending radius / 5 / mm
Duration / 10 / hour
Temperature / 20 ~ 25 / ℃
Humidity / 50 ± 20 / %
9.3.2 Dynamic Bending Test
9.3.2.1 Attach the test sample on the test apparatus, the dynamic bending radius and the motion speed should be setup and maintained to a steady condition. The test sample must be contained under the defined environmental condition during the whole mechanical test procedures. An exemplary test condition is listed in Table 2.
Table 2 Test conditions of the dynamic bending test
Parameter / Value / UnitBending radius / 5 / mm
Motion speed / 0.5 / cycle/sec
Temperature / 20 ~ 25 / ℃
Humidity / 50 ± 20 / %
9.3.3 Folding Test
9.3.3.1 Attach the test sample on the test apparatus, the folding radius and the motion speed should be setup and maintained to a steady condition. The test sample must be contained under the defined environmental condition during the whole mechanical test procedures. Table 3 demostrates an exemplary test condition.
Table 3 Test conditions of the folding test
Parameter / Value / UnitFolding radius / 5 / mm
Motion speed / 0.5 / cycle/sec
Temperature / 20 ~ 25 / ℃
Humidity / 50 ± 20 / %
9.3.4 Rolling Test
9.3.4.1 Attach the test sample on the test apparatus, the rolling radius and the motion speed should be setup and maintained to a steady condition. The test sample must be contained under the defined environmental condition during the whole mechanical test procedures. Table 4 lists an exemplary test condition as follows.
Table 4 Test conditions of the rolling test
Parameter / Value / UnitRolling radius / 5 / mm
Motion speed / 0.5 / cycle/sec
Temperature / 20 ~ 25 / ℃
Humidity / 50 ± 20 / %
9.4 WVTR measurement
9.4.1 WVTR test should be tested using a well calibrated WVTR test equipment after mechanical test.
10 Related Documents
[1] IEC 61747-5:1998, Liquid crystal and solid-state display devices – Part 5: Environmental, endurance and mechanical test methods
[2] IEC 62341-5:2009, Reliability of organic light emitting diode (OLED) displays – Part 5: Environmental testing methods
[3] ASTM 1249-06 Standard test method for Water Vapor Transmission Rate through plastic film and sheeting using a modulated infrared sensor.
[4] IEC 62715: Flexible display devices – Part 6-1: Mechanical stress test methods.
[5] IEC 62715: Flexible display devices – Part 6-2: Environmental testing methods.
[6] Tsai-Ning Chen, Dong-Sing Wuu, Chia-Cheng Wu ,Ray-Hua Horng, Hsiao-Fen Wei, Liang-You Jiang, Hung-Uang Lee, Yu-Yang Chang, "Deposition and characterization of ultra-high barrier coatings for flexible electronic applications," Vacuum 84, pp. 1444–1447 (2010).
APPENDIX 1
REPORTING FORM (DEMO)
NOTICE: The material in this Appendix is an official part of SEMI [designation number] and was approved by full letter ballot procedures on [A&R approval date].
Table 5 and Table 6 summarize the examples of results for the static test and dynamic test respectively.
Table 5 Summary of the static test results
Display model no. / TEST 1001Mechanical Test Method / Temperature (oC) / 23
Humidity (%) / 55 %
Mechanism / Folding Test
Radius (mm) / 5
Duration / 100 hours
WVTR Measurement / Temperature (oC) / 23
Humidity (%) / 55 %
WVTR_before (g/m2·day) / 5 ´ 10-3
WVTR_after (g/m2·day) / 1 ´ 10-3
Table 6 Summary of the dynamic test results
Display model no. / TEST 1001Mechanical Test Method / Temperature (oC) / 23
Humidity (%) / 55 %
Mechanism / Folding Test
Repeat times / 100,000
Radius (mm) / 5
Speed (cycle/minute) / 20
WVTR Measurement / Temperature (oC) / 23
Humidity (%) / 55 %
WVTR_before (g/m2·day) / 5 ´ 10-3
WVTR_after (g/m2·day) / 5 ´ 10-3
NOTICE: SEMI makes no warranties or representations as to the suitability of the Standards and Safety Guidelines set forth herein for any particular application. The determination of the suitability of the Standard or Safety Guideline is solely the responsibility of the user. Users are cautioned to refer to manufacturer’s instructions, product labels, product data sheets, and other relevant literature, respecting any materials or equipment mentioned herein. Standards and Safety Guidelines are subject to change without notice.
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