national institute of metrology(nim), china - · pdf filenational institute of...

National Institute of Metrology(NIM), China

LIN Yandong

2016.9.22

CCPR meeting

Challenges 1

2

3

5

Solutions

LED Filament Standard Lamps

Summary

4 Results

LED Sources in Photometry

Content

• Incandescent lamps are rapidly phasing out around the world.

»

LED Sources in Photometry-Challenges

Source: wikipedia 2016.9

Source: wikipedia 2016.3

• LED lamps are widely used


• Challenges for photometry: Light sources to be measured are significantly different from standard lamp

– (1) Spatial distribution of luminous intensity: directional vs uniform


LED Bulb Incandescent Lamp

• Challenges for photometry – (2)Spectral power distribution:

• Large deviation from CIE illuminant A – Spectral shape – narrowed band


• This presentation mainly focus on Luminous flux ( Luminous intensity, illuminance, luminance)

• Solutions: measurement facility or standard artifact • 1. To set up a goniophotometer or a high quality integrating sphere measurement

facility and make spatial distribution corrections – Pros: Suitable to all kinds of LED lamps – Cons: High cost for each measurement facility

• Goniophotometer: less efficient • integrating sphere: not easy for users at different level of lab to make the

corrections

• 2. To establish a set of standard LED lamps for the maintenance and dissemination of photometric quantities

– Pros: • Easy to disseminate and keep the accuracy • Low cost for the whole traceability system

– Cons: How many kinds of LED lamps are necessary?

LED Sources in Photometry-Solutions

• Characteristics of standard lamp: – Spatial luminous intensity distribution – Stability: short term and long term – Reproducibility – Robust: transportation – Warm-up time: short – ------

• A good candidate of standard lamp:

– LED Filament Lamp

LED Sources in Photometry- LED Standard Lamps

Comparable to incandescent lamp,

much shorter than normal LED lamps

Luminous Flux Vs. time (s)

Warm up time

Characterization of LED Filament Lamp LED Sources in Photometry

-Results of LED Filament Standard Lamps

Stability in 53min after 6.5 min warm-up: The fluctuation is 192ppm( peak-peak), 45 ppm(stdev).

lamp after seasoned

Characterization

Short term stability

LED Sources in Photometry - Results of LED Filament Standard Lamps

0.998

0.999

1

1.001

1.002

1.003

0 5 10 15 20 25 30 35 40 45 50 55 60

rela

tive

TLF

Time/m 0.9998

0.9999

1

1.0001

1.0002

0 10 20 30 40 50 60

rela

tive

TLF

Time/m

Characterization

4W LED Filament Lamp after 2000 h seasoning


Stability

0.9993

0.9994

0.9995

0.9996

0.9997

0.9998

0.9999

1

1.0001

1.0002

0 5 10 15 20 25 30 35 40

relti

ve T

LF

time/h

stability of 35 hours

2666

2667

2668

2669

0 10 20 30 40

CC

T

Time/h

Characterization

0.9995

1.0000

1.0005

1.0010

1.0015

1.0020

Rel

ativ

e Va

lue

Operating time(h)

Aging Characteristics of a new 4W LED Filament Lamp

Voltage

Current

Luminous Flux

0.2 5 10 15 20 25 30

The decrease of Luminous Flux is 0.16% The decrease of Voltage is 0.05%


Aging

Aging (2475h)


0.982

0.984

0.986

0.988

0.990

0.992

0.994

0.996

0.998

1.000

1.002

0 500 1000 1500 2000 2500 3000

Nor

mal

ized

Lum

inou

s Fl

ux

operating time/h

Aging Characteristics of DC Lamp

DC20160229-1#

DC20160229-2#

DC20160229-3#

DC20160229-4#

Aging (2475h)


0.9750

0.9800

0.9850

0.9900

0.9950

1.0000

1.0050

0 500 1000 1500 2000 2500 3000

Nor

mal

ized

lum

inou

s flu

x

operating time/h

Aging of AC lamp

AC20160229-1#

AC20160229-2#

AC20160229-3#

AC20160229-4#

Within 0.1%

Reproducibility

1)Turning on ;2) Burning 24 min;3) Turning off 30 min 4) Turning on…Repeat for 3 rounds

Short-term reproducibility:


0.998

1.000

1.002

1.004

1.006

1.008

1.010

1.012

0 5 10 15 20 25 30

a.u.

time/m

reproducibility

Long-term Reproducibility (5 months)

Characterization

Stored in the laboratory without burning except for measurement.

17-avr. 14-mai 21-août 02-sept.DC201611 1.0000 1.0007 1.0001 1.0000DC201615 1.0000 0.9986 0.9987 0.9975DC201616 1.0000 0.9994 0.9995 0.9989

0.99550.99600.99650.99700.99750.99800.99850.99900.99951.00001.00051.0010

Rel

ativ

e C

hang

es o

f LF

After 500h burning


Flicker

Characterization

Characterization

Standard AC driven LED filament lamp

Standard DC driven LED filament lamp

There is no flicker for LED filament standard lamp.

AC incandescent lamp

Commercial LED filament lamp


Burning at different current of lamp AC20160229-7#

Characterization

Characterization

0.93

0.94

0.95

0.96

0.97

0.98

0.99

1

1.01

1 29 57 85 113

141

169

197

225

253

281

309

337

365

393

421

449

477

505

533

561

589

617

645

673

701

10mA20mA

Relative TLF Vs. time(s)

Current TLF/lm x y CCT/K

10mA Initial 245.38 0.4684 0.4190 2649

End 240.49 0.4682 0.4189 2650

20mA Initial 486.94 \ \ \

End 465.37 0.4664 0.4179 2667


Burning position

Characterization

Angle Photocurrent

Relative Photocurrent

0° 6.8643 1.0004

45° 6.8613 1.0000

90° 6.8613 1.0000

135° 6.8645 1.0005

180° 6.8677 1.0009

225° 6.8698 1.0012

270° 6.8709 1.0014

315° 6.8688 1.0011

4W lamp is not sensitive to burning position, while 8W shows sensitive to burning position.

4 W LED Filament Lamp

Angle Photocurrent

Relative Photocurrent

0° 14.991 1.0035

45° 14.958 1.0013

90° 14.939 1.0000

135° 15.016 1.0052

180° 14.986 1.0031

225° 15.038 1.0066

270° 15.037 1.0066

315° 15.013 1.0050

8 W LED Filament Lamp

0°

45°

90°

135°

180°

225°

270°

315°

4W 8W

LED Sources in Photometry -Results of Standard Filament LED Lamps

Temperature dependent properties

Characterization

Characterization LED Sources in Photometry

- Results of LED Filament Standard Lamps

0.97

0.975

0.98

0.985

0.99

0.995

1

1.005

20 22 24 26 28 30

Relative TLF

Temperature（℃）

Luminous Flux Vs.Temperature

LED Filament 1

LED Bulb

Incandescent Lamp

LED Filament2LED Filament Lamp: 0.14%-0.20%/℃

Characterization of LED Filament Lamp

Spatial luminous intensity distribution of different type of LED filament lamp (TFL)


LED filament lamp for luminous intensity

Characterization

Characterization

Distance d/m Photo

Current ip

ip*d^2 Deviation

(normalized at 6999.1mm)

0.4774 377.49 86.0340 -0.02%

0.9802 89.547 86.0360 -0.02%

1.4918 38.683 86.0877 0.04%

1.9613 22.374 86.0660 0.01%

2.8637 10.491 86.0327 -0.02%

4.2080 4.8568 86.0006 -0.06%

5.8526 2.5098 85.9680 -0.10%

6.9991 1.7567 86.0537 0.00%


Luminous Intensity : 587 cd CCT: 2747 K

Characterization

Summary

Standard LED filament lamp Vs. Incandescent standard lamp

Incandescent lamp

LED filament lamp

Drift rate 0.02% About 1/10 of Incandescent lamp

Life time <2000 h >5000 h Warm up time 5-10 min 6-12 min Short time stability 0.02%-0.05% 0.02%-0.05% Reproducibility 0.1% 0.1% Shelf life good Under investigation Transportation Fragile Robust Temperature dependency

None ~ 0.2% /℃

Spatial distribution Good Under improvement

LED Sources in Photometry-Summary

Characterization

Summary

The clan of standard LED filament lamp

Driver Power CCT Bulb

AC 4W 2700K Clear

DC 6W 4000K Frosted

7W 6500K

Warm White ~2700K Cool White ~4000K Day White ~6500K


LED Sources in Photometry

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