一、光電傳感器工作原理
光(guang)(guang)(guang)電(dian)傳感器(qi)(qi)是(shi)通(tong)過(guo)把光(guang)(guang)(guang)強度的(de)變(bian)化轉換(huan)成電(dian)信號的(de)變(bian)化來(lai)實現控制的(de)。一般(ban)情況下,它是(shi)由(you)發(fa)(fa)(fa)送(song)(song)器(qi)(qi)、接收(shou)器(qi)(qi)和檢測電(dian)路(lu)三部(bu)分構成。發(fa)(fa)(fa)送(song)(song)器(qi)(qi)對準目標發(fa)(fa)(fa)射光(guang)(guang)(guang)束(shu),發(fa)(fa)(fa)射的(de)光(guang)(guang)(guang)束(shu)一般(ban)來(lai)源于半導體(ti)光(guang)(guang)(guang)源,發(fa)(fa)(fa)光(guang)(guang)(guang)二(er)(er)極管(guan)、激(ji)光(guang)(guang)(guang)二(er)(er)極管(guan)及(ji)紅外發(fa)(fa)(fa)射二(er)(er)極管(guan)。光(guang)(guang)(guang)束(shu)不間(jian)斷地發(fa)(fa)(fa)射,或者改(gai)變(bian)脈(mo)沖寬度。接收(shou)器(qi)(qi)有光(guang)(guang)(guang)電(dian)二(er)(er)極管(guan)、光(guang)(guang)(guang)電(dian)三極管(guan)、光(guang)(guang)(guang)電(dian)池組成。在接收(shou)器(qi)(qi)的(de)前面,裝有光(guang)(guang)(guang)學元件(jian)如透鏡和光(guang)(guang)(guang)圈等。在其后面是(shi)檢測電(dian)路(lu),它能濾出有效信號和應(ying)用(yong)該信號。
二、光電傳感器有哪幾種
1、光電傳感器按外殼型狀分類:圓柱型,方型。
光電傳感器的(de)外殼現在(zai)是根據客戶的(de)安裝環境而(er)選(xuan)擇(ze)圓(yuan)型或(huo)方型,這個沒有規定的(de)。
2、光電傳感器按檢測方式分類:對射式、鏡反射式、漫反射式。
對射式光(guang)電(dian)(dian)傳(chuan)感(gan)器(qi)(qi)是光(guang)電(dian)(dian)傳(chuan)感(gan)器(qi)(qi)里檢測(ce)距離最遠的,距離可(ke)達幾米(mi)甚(shen)至十幾米(mi)。安裝必須(xu)要一(yi)個(ge)發(fa)光(guang)器(qi)(qi)和(he)接收器(qi)(qi)對著安裝。
鏡反射式光電傳感器的檢測距離比對射傳感器的檢(jian)測距離稍微短(duan)一些,但(dan)是(shi)安(an)裝卻比對射光傳(chuan)感器方便很多(duo),可以在窄小的空間安(an)裝,只要配合安(an)裝反光鏡(jing)即(ji)可,特點就(jiu)是(shi)專業檢(jian)測透(tou)明(ming)物體的有無。
漫反射光電(dian)傳(chuan)感(gan)器的檢測(ce)距(ju)離就(jiu)不如上(shang)面(mian)兩個(ge)了,但是漫反射光電(dian)傳(chuan)感(gan)器的安裝方式、安裝位置都(dou)比(bi)前兩個(ge)更方便。
3、光電傳感器按光源分類:可見紅光、不可見紅外光、激光。
光(guang)電傳(chuan)感(gan)器的(de)(de)光(guang)源(yuan)是根據客戶的(de)(de)要求和檢(jian)測(ce)物(wu)體、檢(jian)測(ce)環境而選擇(ze),可見光(guang)紅光(guang)和不(bu)(bu)可見紅光(guang)會(hui)(hui)隨(sui)著距離(li)的(de)(de)遠近而改變光(guang)斑(ban)(ban)的(de)(de)大小,但(dan)是激光(guang)卻(que)不(bu)(bu)會(hui)(hui),激光(guang)不(bu)(bu)會(hui)(hui)因為距離(li)而改變光(guang)斑(ban)(ban)的(de)(de)大小,激光(guang)適(shi)合(he)檢(jian)測(ce)小物(wu)體或微型物(wu)體的(de)(de)有無(wu),計(ji)數,定位等(deng)應(ying)用。
三、光電傳感器的實際應用
光電(dian)(dian)傳感(gan)器可以(yi)用于檢(jian)測(ce)直接引起(qi)光量(liang)變(bian)化的(de)非電(dian)(dian)量(liang),如光強(qiang)、光照度(du)、輻射測(ce)溫、氣(qi)體成(cheng)分分析等;也可用來檢(jian)測(ce)能轉換成(cheng)光量(liang)變(bian)化的(de)其(qi)他非電(dian)(dian)量(liang),如零件直徑、表面粗糙度(du)、應變(bian)、位移、振動、速度(du)、加速度(du),以(yi)及(ji)物(wu)體的(de)形(xing)狀(zhuang)、工作狀(zhuang)態的(de)識(shi)別等。
1、條形碼掃描筆
當掃描筆頭在條(tiao)(tiao)(tiao)形(xing)碼(ma)上(shang)移動時,若遇(yu)到黑色線(xian)條(tiao)(tiao)(tiao),發光(guang)(guang)二極(ji)管(guan)(guan)的光(guang)(guang)線(xian)將被(bei)黑線(xian)吸(xi)收(shou),光(guang)(guang)敏(min)(min)三(san)極(ji)管(guan)(guan)接收(shou)不到反(fan)射(she)光(guang)(guang),呈高阻(zu)抗,處(chu)于截(jie)止(zhi)狀態。當遇(yu)到白色間隔時,發光(guang)(guang)二極(ji)管(guan)(guan)所(suo)發出(chu)的光(guang)(guang)線(xian),被(bei)反(fan)射(she)到光(guang)(guang)敏(min)(min)三(san)極(ji)管(guan)(guan)的基極(ji),光(guang)(guang)敏(min)(min)三(san)極(ji)管(guan)(guan)產生光(guang)(guang)電(dian)流(liu)而導通。整個條(tiao)(tiao)(tiao)形(xing)碼(ma)被(bei)掃描過之后,光(guang)(guang)敏(min)(min)三(san)極(ji)管(guan)(guan)將條(tiao)(tiao)(tiao)形(xing)碼(ma)變形(xing)一個個電(dian)脈沖(chong)信號,該(gai)信號經放大、整形(xing)后便形(xing)成脈沖(chong)列,再經計(ji)算機(ji)處(chu)理(li),完(wan)成對條(tiao)(tiao)(tiao)形(xing)碼(ma)信息的識別。
2、簡易感光報警器
當(dang)無光(guang)照時(shi)(shi),硅光(guang)電(dian)池(chi)無電(dian)壓(ya)(ya)產(chan)生,此時(shi)(shi)硅光(guang)電(dian)池(chi)相當(dang)于一個電(dian)阻串接在(zai)放大器的(de)基(ji)極(ji)電(dian)路上(shang)。當(dang)有光(guang)照時(shi)(shi),硅光(guang)電(dian)池(chi)產(chan)生電(dian)壓(ya)(ya),該電(dian)壓(ya)(ya)與R2上(shang)的(de)電(dian)壓(ya)(ya)一起加在(zai)VT1管的(de)基(ji)極(ji),于是(shi)VT1導通,VT2、VT3也隨(sui)之導通,繼電(dian)器K工(gong)作,其觸點(dian)被(bei)吸合,蜂(feng)鳴器發(fa)出報(bao)警聲(sheng)響。
3、產品計數
產(chan)品(pin)(pin)在(zai)傳送(song)帶上運(yun)行時,不斷地遮擋光(guang)(guang)源(yuan)到(dao)光(guang)(guang)敏器(qi)件間(jian)的(de)(de)光(guang)(guang)路,使光(guang)(guang)電脈沖電路隨(sui)產(chan)品(pin)(pin)的(de)(de)有無(wu)產(chan)生一個個電脈沖信號。產(chan)品(pin)(pin)每(mei)遮光(guang)(guang)一次,光(guang)(guang)電脈沖電路便產(chan)生一個脈沖信號,因此(ci),輸(shu)出的(de)(de)脈沖數即代(dai)表產(chan)品(pin)(pin)的(de)(de)數目。該脈沖經計數電路計數并由顯(xian)(xian)示電路顯(xian)(xian)示出來(lai)。
4、光電式煙霧報警器
沒有(you)(you)煙霧(wu)(wu)時,發光二極管(guan)(guan)(guan)發出的光線直線傳播,光電三極管(guan)(guan)(guan)沒有(you)(you)接收信號,沒有(you)(you)輸(shu)出;有(you)(you)煙霧(wu)(wu)時,發光二極管(guan)(guan)(guan)發出的光線被煙霧(wu)(wu)顆粒折射,使三極管(guan)(guan)(guan)接受(shou)到光線,有(you)(you)信號輸(shu)出,發出報警。
5、防盜報警電路
將光電斷路器安(an)裝于(yu)抽屜(ti)的背后,并設一(yi)電(dian)(dian)(dian)(dian)(dian)(dian)源開(kai)關(guan)置于(yu)隱(yin)蔽的地方,當需要防(fang)盜(dao)時(shi),將開(kai)關(guan)合上。平時(shi)由于(yu)擋(dang)(dang)板插入槽口(kou),光電(dian)(dian)(dian)(dian)(dian)(dian)三(san)極僅有暗電(dian)(dian)(dian)(dian)(dian)(dian)流,BG不導通,繼電(dian)(dian)(dian)(dian)(dian)(dian)器J不吸(xi)合。當小偷(tou)撬開(kai)抽屜(ti)時(shi),一(yi)拉開(kai)抽屜(ti)則擋(dang)(dang)板離開(kai)槽口(kou),光電(dian)(dian)(dian)(dian)(dian)(dian)三(san)極管的光電(dian)(dian)(dian)(dian)(dian)(dian)流使R2上產生接近(jin)電(dian)(dian)(dian)(dian)(dian)(dian)源的電(dian)(dian)(dian)(dian)(dian)(dian)壓,BG導通,繼電(dian)(dian)(dian)(dian)(dian)(dian)器吸(xi)合,發出報(bao)警(jing)信號(hao)。
6、公共汽車關門安全指示器
當車門(men)(men)(men)關好時,擋板插入光(guang)電(dian)斷(duan)路器槽(cao)口(kou),光(guang)電(dian)三極(ji)管無工(gong)作(zuo)電(dian)流,其輸(shu)(shu)(shu)出為(wei)高電(dian)平(ping);當三個車門(men)(men)(men)全關好時,則(ze)(ze)相應地輸(shu)(shu)(shu)出三個高電(dian)平(ping)信(xin)號。則(ze)(ze)與(yu)門(men)(men)(men)的輸(shu)(shu)(shu)出為(wei)高電(dian)平(ping),綠燈亮。若(ruo)其中(zhong)有一個車門(men)(men)(men)沒關好(或(huo)沒關嚴),則(ze)(ze)與(yu)門(men)(men)(men)輸(shu)(shu)(shu)出為(wei)低電(dian)平(ping),使紅燈亮。