by : r. s. mandal · 2006. 5. 10. · t5 good t12. 70% t12 80% t8 t5. visual environment vp visual...

By : R. S. Mandal

Light Sources

Heat radiation Electrical radiation Luminescenceglow worm

natural

light sources

sun

lightning

Heat radiation Electrical radiation Luminescence

incandescent lamps mercury lamps

(without phosphor)

metal haline lamps

sodium lamps

diodes

blended mercury lamps

fluorescent lamps

mercury lamps (with phosphor)

tungsten halogen lampsartificial

light

sources

Light Sources

Basics of lighting

Luminous flux

Luminous flux is the light output

of a light source.

Unit: 1 lumen (lm)

Light intensity

Light intensity is the measure

of lightoutput in a specified

direction.

Unit: candela (cd)

Light intensity

Basics of lighting

Basics of lighting

Illumination

Average illumination of a

surface is luminous flux

per unit area.

Lux =Lumen

m2

300 Luxroom center

2500 Luxinside window

10 Lux in the cellar

6000 Luxunder marquee

100000 Luxin the Sun

10000 Lux in the shadow

Illumination (Lux)

Basics of lighting

LuminanceLuminance is the measure of the

brightness of a surface

upon the eye.

Unit: 1 candela/m2 (cd/m2 )

Luminance depend on the surface

size seen and the light intensity,

reflected by the surface regards

the eye.illiuminated surface

visible surface

light intensity

T12

65%

T8

72%

T5

85%

6000K Daylight

4000K Cool White

3000K Warm White

2,700K Warm

ModelingModelingModeling

Relative response

of the human eye

to the colours

present in daylight

380

0,5

1,0

0

780

700 (nm)600500400

Sunbed lamps

Photocopying lamps

Black-glass lamps

U.V. I.R.Light

GLS lamps

Halogen lamps

Fluorescent lamps

Low pressure sodium

HID lamps:

- mercury HQL (MBF)

- sodium NAV (SON)

- metal halide HQI

Heating lamps

(cooker lamps)

Natriumdampf-Niederdrucklampen

The effect of colour on visibility

BetterT8

BestT5

GoodT12

70%

T12

80%

T8

T5

VISUAL ENVIRONMENTVISUAL ENVIRONMENTVpVp Visual PerformanceVisual Performance

Visual AmbienceVisual Ambience VaVa VcVc VVisualisual ComfortComfortTyping

VDUTelephoning

Thinking

Reading

Writing

Discussion

QUALITY FEATURES IN LIGHTINGQUALITY FEATURES IN LIGHTING