cảm biến phát xạ.ppt

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Bi tho lun: CM BIN PHT X (EMISSION SENSOR)Sinh vin:.H Minh Huy Trn Quang Khnh. L Mnh Khi.

Ni dung

1.1 1.2 1.3 1.4 1.5 1.6

khi qut. nguyn l hot ng chung. cc phn t cm bin pht x. cu to chung. phn li cm bin pht x. ng dng

1.1 .KHI QUT

1.1.1 Khi nim 1.1.2 C ch pht x

1.1.1 Khi nim

Cm bin pht x l loi cm bin m tn hiu quang c chuyn i thnh tn hiu in nh hin tng pht x quang in. Hin tng pht x quang in l g? Hin tng pht x quang in hay cn gi l hiu ng quang in ngoi l hin tng cc in t c gii phng khi b mt vt liu to thnh dng khi chiu vo chng 1 bc x nh sng c bc sng nh hn ngng nht nh v c th thu li nh tc dng ca in trng.

1.1.2 c ch pht xC ch pht x xy ra qua 3 giai on: + Hp th photon v gii phng in t bn trong vt liu. + in t va gii phng di chuyn n b mt. +in t thot kh b mt vt liu.

1.2 nguyn l hot ng chung

Nguyn l hot ng: Khi chiu vo ngun sng thch hp vo cm bin, tnh cht dn in ca cm bin thay i, lm mch tn hiu cm ng thay i theo. Nh vy thng tin nh sng c chuyn thnh thng tin ca tn LED hiu inAM P

AM P

V A T T H E

PhotoTransistor

1.2 nguyn l hot ng chung

u pht ca cm bin pht ra mt ngun sng v pha trc. Nu c vt th che chn, ngun sng ny tc ng ln vt th v phn x ngc li u thu, u thu nhn tn hiu nh sng ny v chuyn thnh tn hiu in. Tu theo lng nh sng chuyn v, m chuyn thnh tn hiu in p v dng in v khuych i thnh tn hiu ra. (Hnh 6.1)

1.3 cc phn t cm bin pht x

1.3.1 T bo quang in solar cell. 1.3.2 t bo quang dn chn khng (vacuum

photoconductive cell)

1.3.3 t bo quang dn np kh (gas-filled

photoconductive cell)

1.3.1 t bo quang in-solar cell

1.3.2 t bo quang inT bo quang in: l ng chn khng c 2 cc A v K ni vi ngun in. Khi chiu nh sng c nng lng thch hp vo Katt s lm in t thot khi K v b A ht to thnh dng in.

1.3.2 t bo quang dn chn khng

Gm 1 ng hnh tr c 1 ca s trong sut c ht chn khng, p sut khong 106 108 mmHg.

1.3.3 t bo quang dn kh

T bo quang in dng kh c cu to nh t bo quang in chn khng, ch khc bit ch l t bo quang in dng kh th ng thy tinh cha y kh .Thng l kh Ag(acgon) di p sut 10-1 10-2 mmHg

1.4. cu to chungCu to

1.4 Cu to chungLED u pht

AMP

u thu

AMP

Photo-transistor

Vt Th

1.4

in p

Cu to

in p

ON Mc ngng

OFF

Cng sngLng nh sng nhn v s c chuyn t l thnh tn hiu in p (hoc dng in) v sau c khuch i.

Cng sngSensor xut tn hiu ra bo c vt nu mc in p ln hn mc ngng

1.5 phn loi cm bin pht x

1.5.1 1.5.2 1.5.3 1.5.4

cm cm cm cm

bin bin bin bin

quang pht x c lp . quang pht thu chung. quang khuch i. quang phn x gii hn

1.5.1 cm bin quang thu pht c lp

c im: tin cy cao Khong cch pht hin xa Khng b nh hng bi b mt, mu sc vtKhong cch pht hin au phat au thu

1.5.2 Cm bin quang pht thu chung

c im: D lp t. B nh hng bi mu sc, b mt vt, nn . . .

au phat va au thu

Khoang cach Phat hien

Gng

1.5.3 Cm bin quang khuych i

c im: D lp t. B nh hng bi mu sc, b mt vt, nn . . .

Khong cch pht hinVt

1.5.4 Cm bin quang phn x gii hn

c im: Ch pht hin vt trong vng pht hin gii hn Khng b nh hng bi mu nn pha sau cm bin L tng cho nhiu ng dng cn trit tiu nn.Khong cch pht hin. Trc thu

Trc pht

V t

1.6 ng dng

1.6.1 ng dng trong truyn hnh. 1.6.2 ng dng trong cng nghip

1.6.1 ng dng trong truyn hnh.

ng dng trong my nh, my quay phim,... B phn cm nhn nh sng c bn ca CCD l MOS hot ng nh mt photodiode v thit b lu tr Ca (gate) v b mt to thnh mt t in, trong Gate c phn cc dng Bc x quang i vo thit b qua Gate v lp Oxide lm gii phng electron vo vng cha Mt electron trong vng cha t l vi cng bc x

1.6.1 ng dng trong truyn hnh

o mt in tch c th thc hin bng cch phn cc ngc MOS x qua mt in tr R in p V0 s t l trc tip vi cng nh sng Cm bin CCD gm lng ln cc t MOS t gn nhau Cc t MOS c o mt in tch ln lt theo tng hng CCD c th xem nh mt mng b nh, c duy tr tnh ton vn ca thng tin cho ti khi c c ra cm nhn mu sc, cc b lc c s dng tch cc mu thnh cc thnh phn c bn (RBG) Mi mu sc c bn c cm nhn ring bit v to thnh mt phn ca tn hiu. Mt CCD mu s bao gm 3cell cho mi pixel (mi cell cho 1mu c bn)

1.6.2 ng dng trong cng nghip

1.6.2.1 Pht hin bng nim phong trn np l/hp 1.6.2.2 Pht hin mu bnh trn bng chuyn. 1.6.2.3 Phn bit chiu cao ca np.

Pht hin bng nim phong trn np l/hp

Np l/hp c bc bi mt lp plastic bo v nim phong ngn khng kh, v bc ny rt mng, trong sut, v bng lng. Mt sensor truyn thng khng th pht hin c chnh xc i tng c bng cao nh vy. Omron sng ch ra loi sensor c th p ng c yu cu trn l: E3X-NL11 dng vi u E32-S15L1 vi tin cy cao

Pht hin mu bnh trn bng chuyn.

Pht hin mu bnh, ko vi kch tht v hnh dng, mu sc khc nhau m khng cn phi ci t, thit lp phc tp. E3S-CL l loi Photosensor ca OMRON vi khong cch pht hin xc nh v iu chnh c d dng.

Phn bit chiu cao ca np.

E3G-L1 l loi photosensor t c khong cch th h mi. N c th pht hin 1 cch chnh xc s khc bit d l nh nht v chiu cao vt. Hot ng ca sensor khng b nh hng bi mu sc, cht liu, nghing dc, bng v kch tht vt th. C th d dng chnh c khong cch pht hin ca sensor bng nn hin th kp.