표제지

목차

ABSTRACT 12

I. 서론 15

II. 이론적 배경 17

A. LED 등기구 17

1. LED 17

2. LED 동향 18

B. LED 램프용 SMPS 20

1. 전원공급장치 20

2. SMPS의 구조 21

C. 신뢰성 22

1. 신뢰성 평가 22

2. 가속시험 23

III. 열화분석 및 설계 26

A. 필드 사례조사 및 분석 26

B. SMPS 판정기준 27

1. 품질 및 안전기준 27

2. 신뢰성 기준 28

C. 메커니즘 분석 30

1. LED 램프용 SMPS 고장 30

2. FTA 37

3. FMEA 38

D. QFD 설계 40

1. QFD 1단계 40

2. OFD 2단계 41

E. 내구성 실험법 설계 42

1. 고온 동작실험 설계 42

2. 고온고습 동작실험 설계 43

3. 고온 방치실험 설계 45

4. 고온고습 방치실험 설계 45

IV. 실험 결과 및 고찰 47

A. 고온 동작실험 47

1. 누설전류 측정 47

2. 고장분석 57

B. 고온고습 동작실험 59

1. 누설전류 측정 59

2. 고장분석 68

C. 고온 방치실험 75

D. 고온고습 방치실험 78

V. 제안한 실험법의 타당성 검증 81

A. PCB 실험 81

1. PCB 실험 설계 81

2. PCB 실험 결과 84

B. 실험법 판정기준 108

1. 제안한 실험법의 타당성 검증 108

2. 고온고습 동작실험 결과 112

3. 고온고습방치 실험결과 114

VI. 결론 116

1. 고온 동작실험 116

2. 고온고습 동작실험 117

3. 고온 방치실험 117

4. 고온고습 방치실험 118

5. 재현실험 및 검증 118

참고문헌 120

Table 2-1. Comparing the power supply 20

Table 2-2. Acceleration factor model 24

Table 3-1. Status of domestic fire accidents each item(Top 10) 27

Table 3-2. Performance tests of LED converter 28

Table 3-3. Environment tests of LED converter 29

Table 3-4. Life tests of LED converter 30

Table 3-5. SMPS main cause failure analysis 32

Table 3-6. Power Circuit Failure Analysis and Improvement 36

Table 3-7. FMEA of LED Lighting SMPS 38

Table 3-8. QFD Step 1 40

Table 3-9. QFD Step 2 41

Table 3-10. High temperature operating test methods 43

Table 3-11. High temperature and high humidity operating test Methods 44

Table 3-12. High temperature storage test methods 45

Table 3-13. High temperature and high humidity storage test methods 46

Table 4-1. Leakage current measurement of the product A(50℃) 48

Table 4-2. Leakage current measurement of the product B(50℃) 49

Table 4-3. Leakage current measurement of the product C(50℃) 50

Table 4-4. Leakage current measurement of the product A(70℃) 51

Table 4-5. Leakage current measurement of the product B(70℃) 52

Table 4-6. Leakage current measurement of the product C(70℃) 53

Table 4-7. Leakage current measurement of the product A(90℃) 54

Table 4-8. Leakage current measurement of the product B(90℃) 55

Table 4-9. Leakage current measurement of the product C(90℃) 56

Table 4-10. Leakage current measurement of the product A(85℃, 40% R.H.) 59

Table 4-11. Leakage current measurement of the product B(85℃, 40% R.H.) 60

Table 4-12. Leakage current measurement of the product C(85℃, 40% R.H.) 61

Table 4-13. Leakage current measurement of the product A(85℃, 60% R.H.) 62

Table 4-14. Leakage current measurement of the product B(85℃, 60% R.H.) 63

Table 4-15. Leakage current measurement of the product C(85℃, 60% R.H.) 64

Table 4-16. Leakage current measurement of the product A(85℃, 85% R.H.) 65

Table 4-17. Leakage current measurement of the product B(85℃, 85% R.H.) 66

Table 4-18. Leakage current measurement of the product C(85℃, 85% R.H.) 67

Table 4-19. Over voltage test result after high-temperature test 76

Table 4-20. Over voltage test result after high temperature and high humidity test 79

Table 5-1. Production of PCB pattern 82

Table 5-2. PCB environment reproduction test 83

Table 5-3. Free solder PCB insulation resistance(120℃) 86

Table 5-4. OSP PCB insulation resistance(120℃) 89

Table 5-5. Free solder PCB insulation resistance(60℃, 90% R.H.) 92

Table 5-6. OSP PCB insulation resistance(60℃, 90% R.H.) 97

Table 5-7. Free solder PCB insulation resistance(85℃, 85% RH.) 103

Table 5-8. OSP PCB insulation resistance(85℃, 85% RH) 106

Table 5-9. Test methods for fire and shock 110

Table 5-10. High-temperature & high-humidity test 112

Table 5-11. High-temperature & high-humidity operation test results(product D) 112

Table 5-12. High-temperature & high-humidity operation test results(product E) 113

Table 5-13. High-temperature & high-humidity operation test results(product F) 114

Table 5-14. High-temperature & high-humidity non-operation test results... 115

Table 5-15. High-temperature & high-humidity non-operation test results... 115

 Recently, the lighting market is showing a trend of increasing prevalence of various lighting products, due to the increases in national income and industrial development. Among the lighting products, LED lightings are replacing existing lighting as an environment-friendly and energy-saving industrial product since 2000s. LED lightings have made ​​continuous technology development and the LED lightings market is expected its rapid growth for the future. As demand of the LED lightings are increasing reliability, light weight and high efficiency of the power supply have become necessary elements of LED lightings. The SMPS(Switching Mode Power Supply) is a device that meets these requirements. The SMPS which uses a high speed witching system makes possibilities of miniaturization and high efficiency of the light product. So the use of the SMPS is gradually expended as a lighting industrial trend. In the past, the study of lighting was focused on the efficiency and miniaturization of the SMPS but nowadays reliability and safety requirements are more required to study due to the increases of domestic use. The fire accidents which occur from the mechanical factors of electronics are counted around 14,500 cases(34%) causing 400 people casualties(20%) and 9,000 billion won in property damage(30%) as the annual average in last three years, and the electronic fire accidents are not reducing each year but rather increasing. The SMPS of LED lighting is considered as one of the major causes for electronic fire accident, as it takes the fifth position of reasons for domestic fire. The main reason for the fire and the electric shock causing from the SMPS is deterioration of the product due to long-term use. The expansion and the diversification of imported items are also one of main factor for increasing percentage of the fire and electric shock accidents of LED lighting power supply. The manufacturers have also tried to prevent the increase of fire and electric shock accidents through an improvement in manufacturing technology and quality of product. However, there is a limit that prevents the fire and the electric shock accidents from the degradation products. The SMPS for conventional LED lighting is under KC(Korea Certification) certification exam as a target product safety certification. Aside from it, there are a variety of criteria, such as KS (Korea Standard), MIL standard. However, as those criteria are standards for safety and quality aiming at new product, it is not appropriate to apply the standard to deteriorated product due to prolonged use.

In this thesis, I proposed design and analysis of degradation test for LED lamp SMPS. I designed FTA(Fault Tree Analysis), FMEA(Failure Mode and Effect Analysis) in order to analyze the mechanism of the degradation for LED lamp SMPS and designed durability experiments on environment(high temperature operation test, high temperature high humidity operation test, high temperature operation test, high temperature operation test, high temperature high humidity non operation test, high temperature non operation test)experimented through the two-step QFD(Quality Function Deployment) and tested on designed tests. After test, I performed reproducible tests through environmental conditions on the PCB electrochemical-migration.