??????????????? ??????????? (Thermocouples and Thermopiles)

1
????? 3 ????????????
??????????????????????????????????

• ?????????????????????
• ??????????????? ??????????? (Thermocouples and
  Thermopiles)
• ??????????? ???????????????? (Bolometer and
  Thermistors)
• ?????????????? (Pyroelectric)
• ????? Golay cell
• ????????????????????
• ??????????????????????????????( Photoemissive)
  (phototube photomultiplier tube)
• ??????????????????????? (Photoconductive)
• ???????????????????????????? ( Photo voltaic )

2
??????????? Bolometer

• ???????EMW ??????????????????????? far-IR
  ????????
• ?????????????????????? ?????????? ??????? ???
  ????????????????????????? ?????????????????

http//bolo.berkeley.edu/bolometers/introduction.h
tml
3
????????????????????????
Photo tube
Photo current i
Ammeter
Anode
3I0
2I0
Photo cathode
I0
Voltmeter
V
V
-V????????
As a detector , i gt0 ????? 1. V lt -V ????????
2. f??? gt fo ???? l??? lt lo
( Photo current ? photon rate )
4
Photo multiplier tube
???? Photo tube ????? dynode ???????????????????
??????????
Last dynode
Vacuum
terminal
Anode
Electron multiplier (dynoes)
Photo cathode
5
??????????? 1. linearity , Stability ????? 2.
??????????????????????????????????????????
photocathode 3. ???????????????????? single
photon 3. ????????????????????????? 4.
????????????????????????????? ???????????????????
??????????? 4. ????????? ???????
6
?????? P-N
i
diode
i0 ? 10-9 A
V
-diode -solarcell -LED
n-ideality factor
Shockly diode I-V equation
7
?????? P-N ?????????
p
n
i
W
R
e
V
I0 (???????)
I1
I2
I3
I3gt I2gt I1
8
??????????????? P-N ???? Photodetector
i

• 1. Photovoltaic mode
• ?????????????????????????(????????)
• ???????????????????????????(??????????????)
• ???????????????????????? (log)
• ???????????????????????????

V
I0 (???)
I1
2I1
9

• 2. Photoconductive mode
• ?????????????????? ????????????????????????????
• ?????????????????? ??????????????????
• ??????????????????????????
• ????????????????????????

???????????????? ??????????????
i
V
I0 (???)
I1
2I1
???????????? ?????????????????
10
????????? ????????????? 1. ????????????? ???????
???????????????? Photodiode, ????????????????
,????????? 2. ????????????????????????????????
???????????????????? ?????????? 3.
?????????????????????????????????(????????????????
???????) 4. Stability ?????
11
??????????????? (LDR, Photocell)
gt ???????? CdS ?????????????????????????????????
?????? gt ????????????? photoconductive
(???????????????????????)
12
Light response curve
IL-????????? V-??? ????? E-?????????????
13
??????????? 1. ????????????? ??????? 2. ???
?????????????????????? ????????????????? 3.
????????????????????????? ????????????????????
??????????? ??????????? ???????????????? 4.
?????????????????????? ????????????? 5.
Nonlinear 6. Stability ?????
14
Metal-Oxide-Semiconductor (MOS) capacitor
???????????? MOS
??????????????????
Metal


SiO2
- - - - - -
- - - - - -

- - - - -

P-Semiconductor
- -
??????????????
- - - - - -
????????????????????????????? MOS
???????????????????????????
??????????????????????????????????????????????????
?????????????????
Thermal relaxation time(tth) --gt
????????????????????????????????????
15
???????????? (image sensing)
area scanner
line scanner
Point scanner
???
???
???
???????????
????????????
???????????
16
Charge-Coupled Devices(CCD)
???????????
t0
t0
Optical generation
Thermal generation
fs
Tlt tth
fs
Tlt tth
- -
- -
Thermal generation
- - - -
fs
- - - -
fs
t tth
t tth
??????????????? ????????
??????????????? ???????????
CCD ???????????????????????????????????? ???????
Thermal generation ????????????
17
CCD as an image sensor
??????????????????????????????(Pixel)
??????????????????? CCD ??????????? e-h
??????????? SiO2 ????? e- ???????????????????????
????????????????





Metal gate
SiO2
- - - -
-
- -
Semi conductor
-
18
????????????????????? Three phase
G1
t
G1
G1
t
G2
G2
G2
G3
G3
G3
t
-
- -
- - -
x
fs
x
??????????????????????????????? 3 ???
?????????????????????????? ??????????????????????
?????????????????????????????????? CCD ???????
pixel
x
?????????????????
-
- -
- - -
19
?????????
Radiometry ????????????????????????????????????
- ???????? 3x1011 Hz(1000mm) --gt 3x1016
Hz(0.01mm) - ?????????????? joules (energy)
??? watts (power) Photometry
??????????????????????????????????????????????? -
???????? 400nm -- 700nm -
????????????????????????????????????????????
-?????????????? lumen-sec (energy) ??? lumen
(power)
19
20
??????????????
21
Radiant Flux (Radiant power) ????????????????????
???? f dQ/dt watt Ex.. Laser He-Ne
???? 5 mW
Radiant Flux Density (Irradiance and Radiant
Existance) Radiant flux per unit area E
df/dA M df/dA watt/m2
Radiant intensity ??????????????????????????????
?? I df/dw watt/Sr
Radiance ????????????????????????????????????????
? ??? ?????????????????? L d2f/(dAcosqdw)
watt/m2.Sr
21
22
?????????????????? (Radiant energy ) Q
watt s ??????????????????? (Luminous energy )
QV lumens
???????????????? , ????????????????? (Radiant
flux ) f watt ????????????????? ,
??????????????? (Luminous flux) fV lumen
??????????????????? (Radiant intensity ) I
watt /sr ???????????????????? (Luminous
intensity) IV lumen/sr , Candela
1 Lumen ltgt Radiant energy of 1/683 watt at a
frequency of 540x1012 Hz, (standard air
wavelength of 555.016 nm )
1 Candela ltgt a source that emits monochromatic
radiation of frequency 540x1012 Hz and with a
radiant intensity of 1/683 watt per steradian
22
23
?????? (Solid angle)
??????????????????? /???????????????
24
?????????????????
V (l) ??????????????????????? Luminous effiency
25

• ?????????????????????????????????? Spectral
  luminous efficacy Kl ???????????????? fv ???
  f
• CIE ( The Commission Internationale de
  lEclairage )
• K (l) gt Kmax V (l)
• Photopic vision ?? Kmax 683 lumen/W ???
  l 555 nm
• Scotopic vision ?? Kmax 1700 lumen/W ??? l
  507 nm

26
???????????????????? (Luminous intensity)
lm/Sr ,Cd
27
????????? (illuminance)
lm/m2 , Lux
28
????????????? (luminance)
?????????????????? (illuminance) ?????????????
??????????? Cd/ m2
28
29
???????????????????????????????????
29
30
Example

• A light bulb emitting 100 W of radiant power is
  positioned 2 m from a surface. The surface
  is oriented perpendicular to a line from the
  bulb to the surface.
• Calculate the irradiance at the surface. If all
  100 W is emittied from a red bulb at l 650 nm.
  
• Calculate also the illuminance at the surface
  

30