Light can be described as a wave of Electromagnetic Radiation, located near the center of the Electromagnetic Spectrum

Transcription

1 LED Color Basics

2 The Spectrum Light can be described as a wave of Electromagnetic Radiation, located near the center of the Electromagnetic Spectrum Different wavelengths are interpreted by the eye as different colors - Visible Region = 380 to 780 nanometers (1nm = meter) - Longer wavelengths = Infrared, Radar, Microwaves, Radio Waves etc. - Shorter wavelengths = Ultra-violet, X-Rays, Gamma Rays, Cosmic

3 Black Body Light Source In physics, a black body is an idealized object that absorbs all electromagnetic radiation that falls on it. Because no light (visible electromagnetic radiation) is reflected or transmitted, the object appears black when it is cold. However, a black body emits a temperature - dependent spectrum of light. This thermal radiation from a black body is termed black-body radiation.

4 What is daylight? Average color temperature April (K) October (K) Direct sunlight 9am-3pm 5,800 5,450 Direct sunlight before 9am & after 3pm 5,400 4,900 Completely cloudy sky 6,700 6,750 Foggy sky 7,500 8,400 Light from a clear, blue sky 26,000 12,000

5 What is daylight? Color influenced by: Elevation above sea level Air pollution

6 The Kelvin Scale K C k candlelight 2680 k 40W incandescent bulb 3000 k 200W incandescent bulb 3200 k sunrise/sunset 3400 k halogen bulb 3400 k twilight k Xenon Lamp / long arc 5500 k sunny daylight at noon k electronic photoflash k cloudy sky k blue sky

7 Color Temperature

8 Color Temperature in Studios Usually all lights inside a TV studio are dimmed by 10% color temperature below 3000 K extension of lamp life time (4 times longer) (according to OSRAM chart)

9 The Mired Scale 2800 steps in Kelvin scale ca. 80 Mired 400 steps in Kelvin scale ca. 80 Mired

10 The Mired Scale Every color temperature can be related to a so called mired-value (micro reciprocal degree Kelvin). exp.: Kelvin Mired Difference Mired Kelvin Mired Kelvin

11 The Mired Scale

12 Different Spectral Characters Continuous-spectrum sources Tungsten halogen Carbon Arc Long-wave Xenon Tungsten Discontinuous-spectrum sources Daylight HMI Florescent Plasma LED Fluorescent Typical LED

13 Light Sources Metal Halide

14 Light Sources Metal Halide Rare Earth Elements: Tin Scandium Sodium Thallium Lithium orange / red radiation blue and green radiation yellow radiation green radiation red radiation

15 Light Sources The Sun CRI 100

16 Light Sources Halogen High Voltage CRI >98 230V 20 lm/w

17 Light Sources Halogen Low Voltage CRI >98 12V / 24V 40 lm/w - Longer lifetime - Shock resistant

18 Light Sources Metal Halide (HMI) Daylight Discharge Lamp 80 lm/w CRI >92

19 Light Sources Metal Halide (HMI) Tungsten Discharge Lamp 60 lm/w CRI >92

20 Light Sources Household Fluorescent Lamp daylight (4300K) tungsten CRI >75 80 lm/w or higher

21 Light Sources Human Eye Senitivity Curve The human eye has different sensitivity for different colors Photopic (normal light) = green peak at 555 nm Scotopic curve (low light) = peak at 507 nm

22 Light Sources Fluorescent Lamp Kino Flo 80 lm/w or higher CRI >93

23 Light Sources Plasma CRI >94 43 lm/w

24 Light Sources ESL Lamps CRI >96 80 lm/w

25 Light Sources LED Magic

26 Light Sources Saves the Planet

27 Light Sources Usual expectations for LED Nearly no energy needed No heat Lives forever Much more light True or not true?

28 Light Sources Energy efficiency High voltage halogen dedolight low voltage Metal Halide (HMI) daylight High CRI fluorescent White Phosphor LED White Phosphor LED CRI > lm/w 40 lm/w 80 lm/w 80 lm/w ~ 60 lm/w (+) (~ 30 lm/w)

29 Light Sources Heat generation High voltage halogen dedolight low voltage Metal Halide (HMI) daylight High CRI fluorescent White Phosphor LED White Phosphor LED CRI > 90 ~ 90% ~ 75% 75% 30% ~ 80-85% ~ 85%

30 Light Sources Operating temperature High voltage halogen dedolight low voltage Metal Halide (HMI) daylight High CRI fluorescent White Phosphor LED White Phosphor LED CRI > C 3100 C 500 C 65 C 85 C max. 85 C max.

31 Light Sources Life expectancy High voltage halogen dedolight low voltage Metal Halide (HMI) daylight High CRI fluorescent White Phosphor LED White Phosphor LED CRI > h h h h h h depending in frequency of ON/OFF cycles. 2 - depending in operating conditions

32 Light Sources Not all LED light sources provide the expected miracles

33 Light Sources performs the incredible

34 Light Sources Typical white LED Typical white LED It was CRI >75 Recently valid improvements, CRI 90 + above 60 lm/w Can come close to 95 perfect color often low output

35 Light Sources Felloni 3 LED CRI TLCI 96-99

36 Light Sources RGBW LED CRI >90 40 lm/w

37 Light Sources RGBW LED Red, Green, Blue and White RGBWA LED Red, Green, Blue, White and Amber No full success. RGBWW LED Red, Green, Blue, Warm White and Daylight White Latest technology Best for skin tones

38 Light Sources Remote Phosphor LED CRI >90 30 lm/w approx.

39 Light Sources White Phosphor LED CRI > lm/w Hopes for Future

40 Color Rendering Groups Colour Rendering Group Colour Rendering Index (Ra) Typical Application Areas 1A Ra Accurate E.g. Colour printing inspection, art galleries, high end retail etc. 1B Ra Good E.g. Retail, Showrooms, Offices, Restaurants,, etc. 2A Ra Moderate E.g. Offices, Classrooms, Supermarkets, etc. 2B Ra Poor E.g. Warehouses, exterior illumination etc. 3 Ra Very Poor E.g. Street Lighting, Parking Areas, Security, etc. 4 Ra Not Important E.g. Street Lighting

41 Color Rendering Groups Important colors for correct skin color rendition

42 Spectral Measurement Isolated blue peak = biohazard Δu'v too big (deviation from Planck curve)

43 LED Binning

44 New dedolight Color Identification dedolight maximal tolerance UV + 0,0054 B = Above the Planck curve green UV - 0,0054 A = Below the Planck curve magenta

45 New dedolight Color Identification B A B0 = +0, ,0009 B1 = +0,001 +0,0019 B2 = +0,002 +0,0029 B3 = +0,003 +0,0039 B4 = +0,004 +0,0049 B5 = +0,005 +0,0054 A0 = -0,0000-0,0009 A1 = -0,001-0,0019 A2 = -0,002-0,0029 A3 = -0,003-0,0039 A4 = -0,004-0,0049 A5 = -0,005-0,0054

46 New dedolight Color Identification Examples: 56B0 31A2 56 = 5600 K B = Color coordinate above Planck curve 0 = UV +0, , = 3100 K A = Color coordinate below Planck curve 2 = UV -0,002-0,0029

47 LED Evaluation TLCI CRI Color Rendition Index TLCI TV Lighting Consistency Index

48 LED Evaluation Litepanels 1x1 Daylight

49 LED Evaluation DLED4

50 LED Evaluation Felloni D50

51 Colorimeter 3 Fotocells with Red, Green and Blue Filters For continuous spectrum only

52 Spectral Measurement ASEQ

53 Spectral measurement Sekonic C-7000 SPECTROMASTER C-7000 spectrometer

54 Spectral Measurement ASENSETEK

55 Spectral measurement ASENSETEK 55

56 CRI Ra, Re, TM30-15

57 IES-TM The Fidelity Index (Rf) Accurate rendition of color under familiar (reference) illuminants. (0-100 scale) Gamut Index (Rg) Average level of saturation relative to reference illuminants.

58 IES-TM Gamut Index (Rg) Rg higher than 100, increase in saturation; lower, decrease. The arrows represent the increase or decrease in chroma.

59 Light Basics The color must be in the light to be seen by the camera!

60 Camera Based Analysis / Reference Light

61 Camera Tests 8 years ago 9 years ago, no good match was possible.

62 Camera Tests 6 years ago Camera preset: 3200 K Camera preset: 5600 K Right side of the face lit with reference light, left side lit with a multi-color LED light, not really achieving matching color

63 Camera Tests 6 years ago KinoFlo Celeb: Preset 3200K KinoFlo Celeb: Preset 3200K

64 Camera Tests 6 years ago Felloni Bicolor HO & DLH4 Felloni Bicolor HO & DLH4

65 Camera Norwegian TV2 Left side = Kinoflo 5600K Right side = Desisti LED daylight Left side = Kinoflo 5600K Right side = DLED4.1 daylight With SONY 1500R Broadcast 3 CCD Camera

66 LED Evaluation Litepanels 1x1 Daylight LED light Reference light

67 LED Evaluation DLED4 LED light Reference light

68 LED Evaluation Felloni D50

69 LED Evaluation Felloni D50 Felloni dedocolor Tungsten 50HO dedolight DLH1x150S 3200K

70 LED Evaluation Felloni D50

71 LED Evaluation Felloni D50 Felloni dedocolor Tungsten 50HO dedolight DLH1x150S 3200K

72 LED Evaluation Felloni D50

73 LED Evaluation Felloni D50 Felloni dedocolor Tungsten 50HO dedolight DLH1x150S 3200K

74 Light Sources Lumen Maintenance IES LM : measuring Lumen Maintenance of LED Light Sources. LM-80 IES TM : projection Long Term Lumen Maintenance of LED Light Source

75 Light Sources Color Maintenance Unlike IESNA TM-21, there are no industry standards to predict long term color maintenance. Color Temperature. CCT describes a yellow-blue axis DLED4T Duv describes a green - magenta axis, if shift below = still good.