Transcript Snesor Physics

OPTIKA
Photometry
Dr. Seres István
Fotometry
Used quantities:
r
Snesor Physics
angle: length fo arc/radius
i

r
i

Central angle of a circle: 2p (radian)
Solid angle: area/radius squared
A
sr  2
r
(steradián = sr)
Central angle of a sphere: 4p (steradián)
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Fotometry
Snesor Physics
The solid angle of an elementary area:
dA  cos 
d 
2
r
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dA

r
dA cos
d
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Fotometry
Snesor Physics
Overview:
Radiometrical quantity
Unit
Fotometrical
quantity
Unit
Emitted power (Φe)
W
Luminous flux
(Φv)
lm
Irradiation (Ee)
(Power density)
W m-2
Illumination (Ev)
lx
Irradiation density (Le)
W m-2
sr-1
Brilliancy (Lv)
cd m-2
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Fotometry
Luminous flux
Snesor Physics
Sensitivity max of the human eye: 555 nm
Power: 1 watt
Luminous flux: 683 lumen
Maximal spectral utilization
lumen
K m  683
watt
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Spectral sensitivity of the eye
(visibility function)
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Fotometry
Luminous flux
Snesor Physics
láthatósági függvény
1
0.8
l (nm)
Vl
480
0.139
490
0.208
500
0.323
510
0.503
520
0.71
530
0.862
540
0.954
550
0.995
555
1
560
0.995
570
0.952
580
0.87
590
0.757
600
0.631
610
0.503
620
0.381
630
0.265
640
0.175
0.6
0.4
0.2
0
350
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450
550
650
hullámhossz (nm)
750
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Fotometry
Luminous flux
Snesor Physics
The energy emitted by a unit time:
dW

dt
  lm
/lumen/
l2
  Km    el V (l )  dl
l1
 el : em itted _ spectral _ power
V (l ) : visibility _ function
Km : maxim al_ spectral _ utilization, (683lm W 1 )
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Fotometry
Snesor Physics
Luminous flux
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Fotometry
Snesor Physics
Illumination:
Luminous flux on a unit surface
d
E
dA
E   lx
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/lux/
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Fotometry
   lm lumen


P W
watt
 
Snesor Physics
Light utilization
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Fotometry
Fotometers
Snesor Physics
Important properties of light sensors
1. The spectral dependence of the sensor is coincidence with the
visibility function V(λ)
2. The photocurrent is proportional to the illumination
3. The angled irradiation is detected as the cosine of the incliment angle
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Fotometry
Photometers
Snesor Physics
•Subjektiv photometry
• Photocell
• semiconductor diode
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Fotometry
Snesor Physics
Subjektive photometry
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Fotometry
Snesor Physics
Subjective photometry
Bunsen fotometer:
Relative measurement
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Weber photometer
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Fotometry
Snesor Physics
Photocell
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Fotometry
Snesor Physics
Photodiode
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Fotometry
Snesor Physics
Photodiode
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Fotometry
Snesor Physics
Photodiode
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Snesor Physics
Fotometry
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Köszönöm a figyelmet!
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