*CHNG IICM BIN QUANGI. T bo quang dnII. PhotoiotIII. PhototranzitoIV. Phototranzito hiu ng trngV. Cm bin quang pht xVI. Cm bin quang nhitVII. Cm bin hnh nh

*I. T bo quang dn 1. Nguyn l hot ng Mu bd loi n, Nd, mc n.lng Wd ln, no nhTrong ti: - gii phng hd do nhit - ti hp ph.trnh ng: tr. thI cn bng: dn trong ti:Chiu sng: - g.phng hd do ch. sng:

- g.phng hd do nhit a(Nd n)- ti hp r.n2 ph.trnh ng: s photon ti mu:s photon h.th:s t g.phng trong 1s v 1 v t.tch: dn khi ch.sng: Nguyn l: chiu a.sng thch hp v mnh n >> nor - h.s tI hptr.thi c.bng:

*2. Vt liu - a t.th: - n t.th: 3. Cc c trng a. in tr in tr ti ph thuc: hnh hc, kch thc, nhit , bn cht v.liu in tr khi ch.sng: gim nhanh khi ri tng Mch tng ng: 2 in tr mc song song:Rco - in tr tiRcp - in tr q.in: b - h s ph thuc v.liu, n., ph .sng, = 0,5 1 CdS, CdSe, CdTe, PbS, PbSe, PbTe Ge, Si t.khit hoc p.tp Au,Cu,In SbIn, AsIn. TD: + PbS, CdS, CdSe: 104 -109+ SbIn, SbAs, CdHgTe: 10 - 103 Rc ph thuc khng tuyn tnh vo

Rco

Rcp

*b. nhy dn: Gc = Gco + Gcp Gco - dn trong ti: Gcp - dn khi c/s: t in p V dng in: dng ti Io = Gco.V dng q.in Ip = Gcp.VIo Ip dng qua TBQD khi chiu sng:I = Ip = (V/b). b - h.s p.thuc v.liu, n. v ph a/sng =0,51 - TBQD l CB khng tuyn tnh, nhy khi ch.sng - nhy V (khi V nh h.ng Joule khng lm thay i n.) p ng p.thuc b.sng

* nhy ph Khi V=10v, b mt =1cm2, S() = 10-110 A/W4. ng dng iu khin rle

*II. Phtit1. Nguyn l hot ng BD n v p tip xc th tip xc, hng ro th- Vd = 0: + Dng kh.tn h.dn c bn Icb do ion ho + Dng h.dn khng c bn Io Hai dng bng nhau ngc chiu - Vd 0: ro th thay i thay i Icb v vng ngho in p ngc - dng ngcchiu sng chuyn tip: vng ngho: pht sinh cp .t-l trng .t-l trng b tch cp do .trng ch.ng cun cng chiu h.dn khng c bn Ir Nguyn l photoit: Phn cc ngc v chiu sng vng chuyn tip tng dng khng c bn (dng ngc Ir)

*2. Cu to Yu cu: a/s phi n c vng ngho a/s suy gim khi i vo vt cht

105 cm-1 lp p phI rt mng: < 5m3. Cc ch hot ng a. Ch quang dn phn cc ngc Vd

*nh gi Vb bng cch o th h mch Voc:

- C/sng yu IpIob. Ch quang th Vd=0 c/sng Ip gim h.th t.xc gim ro th Vb tng Icb sao cho dng qua photoiot Ir = 0Voc nh, p.thuc t.tnh vo Voc ln, p.thuc khng t.tnh o dng ngn mch: ni tt 2 u photodiot bng Rm

*III. Phototranzito1. Nguyn l hot ng Tranzito c lp ch.tip: - cu to- nguyn l hot ng Phototranzito:- tranzito NPN, chiu sng vng B, - ch t .p trn C ph.cc ngc ch.tip B-C - .p ch yu ri trn ch.tip B-C, VBE 0,6 0,7vn c/sng B-C, ch.tip B-C ging photoiot p.cc ngc cho Ir= Io+Ip Ir c xem nh dng baz ca tranzito kh. i ln s t.ng: phototranzito = photodiot (Ir ti baz) + tranzito (kh.i ): Ic = Ir + Ir 2. Cu to

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*3. Ch hot ng a. Chuyn mch th.tin dng nh phn: - c hoc khng c bc x a/s - ln hn hoc khng ln hn ngng b. Ch tuyn tnhtn hiu a/s: (t) = o + 1(t)ic(t) = Ic(o) + S. 1(t)

4. nhyIcp = (+1)Ip

*IV. Phototranzito hiu ng trng 1. Nguyn l hot ng Tranzito h/ng trng (cu to v nguyn l hot ng) Phototranzito hiu ng trng: l tranzito h/ng trng c ch,tip cc ca phn cc ngc v c th chiu sng ch.tip ny iu khin rng knh dn v do lm thay i dng mng

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*Ir = Io + Ip Io - dng ti Ip - dng quang in Ip = Sg. Sg- nhy ca diot cng-knhVGS = Rg(Io + Ip) EgCh.sng tng Ip VGS tng gim b rng knh gim ID2. nhy Ip VGS ID G- h.s kh.i dng ca diot cng-knh Sg- nhy ca phtdiot cng-knh3. ng dng B gim in pEg v V1 c nhVo < V1khi tng Vo tng dn n gi tr ngng

*V. Cm bin quang pht x1. C ch hot ng v vt liu ch to C ch pht x:3 giai on: - hp th photon v g.phng .t bn trong v.liu- .t va c g.phng di chuyn n b mt- .t thot khi b mt vt liu hiu sut lng t : khong 10%, t khi vt qu 30%. Vt liu photocatot:- AgOCs (vng hng ngoi)- Cs3Sb, (Cs)Na2KSb (a/s nhn thy v t ngoi)- Cs2Te, Rb2Te v CsT (vng t ngoi)-hp cht III-V: GaAsx Sb1-x, Ga1-xInxAs (h. ngoi) 3 loi CB pht x:- T bo quang in chn khng- T bo quang in dng kh- Thit b nhn quang

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*2. Thit b nhn quang a. Nguyn l: .t pht x n.lng ln (t phtcatot) bn ph b mt .cc pht x t th cp s t th cp > s t ti khuch i tn hiu b. Cu to:H s kh.i: 1 t s cp va chm to ra t th cp n in cc to ra M = n t th cp c- h s thu in t in cc t - h s chuyn ti M = c(t .)n n = 5 15, h.s pht x th cp = 5 10c, t > 90%, M 106 108c. nhy: Dng catt T()-h s truyn qua ca ca s Dng anot nhy Sk- nhy ca phtcatot

*d. S s dngVm = IA.Rm

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*VI. Cm bin quang nhit1. c trng chung CB quang: thay i t/c vliu do tc dng trc tip tc thi ca a/sCB quang nhit: nlng a/s thay i n CB thay i t/c CB- nng nhitTrng hp nh sng khng i: = oTrng hp nh sng bin iu = o+ 1costB qua ch qu (t) v thnh phn khng i ca nng nhit:Nhn xt: - mun tng T phI gim G - mun gim thi gian p ng phi gim G

* Cc loi cm bin quang nhit:- in tr quang nhit- Cp nhit- Cm bin ho in2.Cm bin ho in a. Nguyn l hot ng Tinh th ho in c phn cc in t pht ph thuc nhit in tch: Q = A. (A- din tch b mt, - mt .tch )Ch.sng nh. tng g.phng .tch trong th tch, chng ch.ng n b mt v trung ho vi .tch b mt gim phn ccd- b dy - in tr sutb. nhy Ch.sng lm tng nh. dn n thay i phn cc in do gy ln dng quang in:

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*nh sng bin iu dng = 1cost bin th.i dng q.in-h s ho in ca v.liu- dn nhit ca v d.tch b.mt nhy dng:c. S s dng S chuyn dng thnh th:

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*VII. Cm bin hnh nh 1. Nguyn l chung- Tp hp ca nhiu CB quang xp theo mt trt t trn mt phng. - CB(x,y) cho tn hiu in q(x,y) t l vi sng E(x,y) ca im nh q.hc (x,y) - Tn hiu ca cc CB c ghi li theo mt trt t v th t nht nh. - Thit b phn tch (c mch ch.i tn hiu) s da trn tp hp cc tn hiu thu c v q.lut ghi cc tn hiu ti hin li hnh nh q.hc trn mn hnh. 2. Cm bin hnh nh t hpL mch t hp gm tp hp cc vi CB v cc b phn tch hnh nh cng ch to trn 1 phin Si bng cng ngh MOS. Mi vi CB l mt t in quang cc nhb tr theo ng thng (t 256 n 2048 t)b tr theo ma trn: 244 hng 488 ct 190 hng 380 ctT hp cc in tch ca cc t theo nhng khong t xc nh c chuyn n cc thanh ghib tr lch nhau cho php ghi v phn tch hnh nh

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