CAM BIEN
SO sanh cac cong nghe
cam bien thay the i khong tiep xuc
V
di bat ki iing dung do thay ddi ludn ed sa can nhac g\da Idi ich va gidi ban ma mdi cdng nghe do dem lai. Chinh vi vay, bai viet nay so sanh bdn logi edng nghe do ladng thay the khdng tiep xuc, daa ra t a van viec chpn li/a cdng nghe do sao cho phii hdp nhat.Viec sir dung cdng nghe thay the khdng tiep xuc trong do ladng chinh xae dang phat trien mot each nhanh chdng.
Ngadi sir dung can do chinh xae hdn, dp phan giai nhd hdn micro hoac nano met, va chdng lai khd khan b'e mat hoac vat lieu khdng the dapc cham trong luc do bao gom silicon, thiiy tinh, chiit deo, thanh phan dien va y te thu nhd, gidng nha di/a tren be mat thac pha'm.
Sa phat trien dd da thiic day trien khai cdng nghe mdi, bao gom sd dieu chinh cdng nghe hien tai cho phii hdp nhu'ng yeu cau do ladng mdi, cai thien dp chinh xae
va dp phan giai cho viec do. Cam bien thay dd'i khdng tiep xuc tien tdi md rpng tinh da dang eiia hinh dang, kich thadc va nguyen ly do. Trong thac te, cung nha ddng xoay va cam bien tam giae lazer, dien dung va cam bien dong tieu la pho bien ngay nay.
Nguyen ly dong dien xoay
Nguyen ly do ddng dien xoay la each do cam iing. Mot cudn day dapc ciip bdi ddng dien xoay chieu va sinh ra tir tradng xung quanh cudn day. Neu mot vat dan dien dadc dat trong tir tradng, ddng dien xoay dadc cam u'ng, tao thanh mot tradng dien theo Luat cam iing Faraday Bp dieu khien tinh toan thay ddi trong nang lapng chuyen dd'i t i i cudn day cam bien tdi vat dich va chuyen dd'i nang ladng dd thanh do ladng sa thay doi .
Phadng phap nay ed the dadc sir dung cho tiit ea vat dan dien, sat tir va khdng mang sat tir, la Idi the ciia phadng
phap nay. Kich thadc cam bien thac sti nhd dadc so sanh vdi eac cdng nghe khac, cdng nghe cd dp chinh xae cao va ngan dadc bui, ban, dp am, dau, ap suiit cao va chiit dien mdi trong do khoang each.
Tuy nhien, tin hieu ra va tuyen tinti phu thupc vao dac diem dien va tir ciia doi tapng. Bdi vay, moi sa dieu chinh va tuyen tinh hda dadc yeu cau. chieu dai Idn nhiit cap la 15m va dadng kinh ciia cam bien tang khi tang pham vi do.
Nguyen ly dien dung
vdi nguyen ly dien dung, cam bien va ddi tadng tac ddng gidng y tadng hai ban CI/C song song ciia tu dien. Hai dien ci/c dadc hinh thanh bdi cam bien va ddi mat ddi tadng. Neu ddng xoay chieu vdi tan so khdng dd'i qua tu cam bien, dp Idn ciia dien ap xoay chieu tren cam bien ty le vdi khoang each giu'a hai cdc cua tu. Dien ap bii ed the dieu chinh ciing mot liic dadc phat ra t i i bd khuyech dai dien. Sau do giai dieu bien ciia ea dien ap xoay, sai lech dadc khuyech dai va dau ra nha mot tin hieu tadng ta.
Bdi vi cam bien dadc cau tao giong nha mot vdng bao ve tu, hiiu nha nhOtig y tadng tuyen tinh va dp phan can eii cac ddi tadng kim loai da dat dadc. Cdng nghe cung daa ra dp on djnh nhiet dp cao, khi thay doi tinh d i n dien ciia ddi tadng khdng cd hieu iing trong do ladng. Cam bien dien dung cung ed the do chiit each dien.
Cdng nghe nay nhay cam vdi thay doi trong khe dien mdi dien trd va vi cd tac dung hieu qua Idn nhiit trong viec lam sach, iing dung khd. Chieu dai cap cung thac sa ngan do hieu irng ciia dien dung cap trong sa dieu chinh mach dao ddng.
Nguyen ly tam giac laser
Trong nguyen ly nay, mot diode laser phdng ra mot diem anh sang nhin thiiy len tren be mat cua vat the dang dadc do.
Anh sang bj phan tan trd lai dadc phan xa tir die'm dd la hadng len tren mot mang CCD bdi he thdng thau kinh quang hoc chat ladng cao. Neu doi tadng thay doi vj (Xem tiep trang 55)
46| TU DONG HOA NGAY NAY • (S6 114 - 4/2010)
HQC &LAM
ngade; KS. Bill Ddc Truyen sinh nam 1975 chii nhiem de tai Cai tien to hdp quan lat godng I8O0 md ham Id, thiet ke iing dung md hinh quang lat vao day hpc;
KS. Doan Van Ha sinh nam 1979 Chii nhiem de tai Nghien ciru u'ng dung tro bay lam phu gia vd cd boat tinh de cai thien cae tinh chiit cd ly chii yeu trong san xuiit dng cdng theo cdng nghe rung ep tai Cdng ty TNHH XDCT Hiing Vadng - TR Hd Chi Minh hoac nha tradng hdp eiia sinh vien Le Thj Ngpc Tii, sinh nam 1987 - ngadi nhan giai thadng ciia To chiic WIPO danh cho nha phat minh tre tud'i nhiit vdi edng trinh
"Nghien ciiu thanh phan vat chiit va dac tinh edng nghe eac da bazan Kainozoi khu vac Ndng Cdng - Thanh hda va Phii Quy - Nghe An theo hadng che tao be tdng dam Ian cho cac dap thiiy dien Idn..." dd la nhu'ng ten tud'i cdn rat tre nhang da lam chii va sang tao dadc nhuYig cdng trinh riit dac biet, dang ne trong gidi nhu'ng ngadi lam nghien ciiu, sang tao KH&CN.
Nhu'ng cdng trinh va cac tac gia neu danh tren ehi la mot gdc nhd ciia ban danh sach giai thadng Vifotec nam 2010, chaa phan anh day dii dien mao ciia he thdng giai thadng da van hanh 15 nam qua. PGS.TS Ho Uy Liem - Q. Chii tjch Lien hiep cac Hpi Khoa hpc va Ky thuat Viet Nam - Tradng Ban to chu'c giai thadng nam 2010 nhan djnh rang, cac cdng trinh dadc chpn liTa tham gia giai thadng hang nam la ket qua nghien ciiu, u'ng dung thupc cac chadng trinh, de tai KH&CN trpng diem cap Nha nadc, cac de tai nghien ciiu giai quyet cac van de KH&CN trong san xuiit ciia cae doanh nghiep. 15 nam to chiic, giai thadng da tap hdp dadc mot lac ladng ddng dao cac nha khoa hpc, cae nha edng nghe trong ea nadc tir cac Vien nghien ciTu, eac tradng dai hpc, cac doanh nghiep tich circ tham gia. Cac cdng trinh dat giai da va dang ap dung trong san xuiit, gdp phan mang lai hieu qua kinh te xa hdi cao, gdp phan thiic day san xuiit ciia eac doanh nghiep, nang cao nang suiit, chiit ladng, ha gia thanh san pha'm, thay the nhap khau, tiet kiem ngoai te cung nha ddng vien, khuyen khich, ton vinh cac tai nang KH&CN ciia dat nadc.
So sanh cat cong nghe cam bien...
(Tiep theo trang 46) tri ddi vdi cam bien, sd di chuyen ciia anh sang dadc phan chieu dadc hadng tdi mang CCD va dadc phan tich tin hieu dau ra vj tri chinh xae ciia ddi tadng. Viec do dadc qua trinh sd hda trong dieu khien tich hdp, sau dd chuyen dd'i thanh dau ra ty le qua tadng ta(I/U) va giao dien sd RS232, RS42 hoac USB .
Ldi ich ciia cam bien tam giae laser bao gom mot chiim diem nhd, pham vi do ladng rat dai la cd the, cam bien boat ddng khdng phu thupc kim loai ddi tadng, va
mot khoang each tham chieu cao giu'a cam bien va ddi tapng.
Phadng thiTc dapc md rpng bdi thiet ke cam bien kha Idn va khoang truyen quang hpc taPng ddi sach dadc yeu cau de cam bien boat ddng tin cay.
Ngoai ra, ddi vdi cac muc tieu
phan xa trac tiep, sir lien ket va •*
djnh cd cam bien dac biet dapc yeu cau.
Nguyen ly dong ti^u
Cdng nghe lam viec bang each tap trung anh sang trang len tren be mat ddi tadng vdi viec sa dung mot he thdng thau kinh quang hpc. Cac thau kinh quang hpc dapc sap xep theo each ma anh sang trang dadc phan tan thanh cac anh sang ddn sac vdi dieu khien dp lech mdi mau. Duy nhiit mot chieu dai bade song dapc tap trung chinh xae tren be mat doi tapng hoac kim loai dapc sir dung cho do ladng.
Be mat phan xa va khuyech tan deu cd the dadc do. Vdi chat lieu trong sudt nha thiiy tinh, do ladng dp day mot phia cd the dat dadc ciing vdi do khoang each. Ngoai ra, bdi vi bd phat va nhan dadc sap xep tren mot true, tranh dadc hieu iing mang chan.
Dong tieu daa dp phan giai tdi nano met va gan nha hoat ddng tach khdi vat lieu ddi tadng. Dap u'ng dadc kich thadc vet den khdng ddi, riit nhd. Thu nhd xuyen tam va true phien ban dong tieu cd kha nang do mui khoan hoac cae Id khoan. sa ban che ciia cdng nghe bao gom khoang each bi gidi han giaa cam bien va ddi tadng. Them niJa, tia ddi hdi mdi tradng sach.
Cac tieu chuan lifa chon quan trpng
- Chi rd edng nghe do nao ed ma ban can de do va tai sao?
- Loai mdi tradng ma cam bien can de boat dong trong (thd, chan khdng, ap suiit cao...)?
- Cd gidi ban khdng gian khdng?
- Tuy chinh so vdi tieu chuan eac cam bien
- sa can nhac g\da dp phan giai va dp chinh xae ed the tiet kiem tien bac va thdi gian, nhang se cam bien thu'e hien dii tot trong iing dung.
- Khi Cam bien thdng thadng chdng lai tieu chuan dadc tinh den, cai thien dp chinh xae ludn tien tdi viec xae djnh lai, ph'an m'en cam bien tich hdp thdng minh, cai thien lap rap cd khi hoac san xuat cam bien tir thanh phan hoac vat lieu tot hdn
THANH HUYEN Theo www.sensor.com
(S6 114 - 4/2010) •* T U OONG HO A NGAY NAY SS
