LED燈珠漏電的原(yuan)因是什么

1、封裝(zhuang)膠(jiao)體老化、因長時(shi)間使(shi)用(yong)過熱導致封裝(zhuang)膠(jiao)體老化從而造成的(de)漏(lou)電(dian)現象是(shi)正常情況，但(dan)是(shi)這(zhe)種情況的(de)幾率非常小(xiao)，因為現在的(de)LED燈珠(zhu)封裝(zhuang)工藝(yi)相對來說比較成熟了，且(qie)專用(yong)的(de)樹脂(zhi)橡膠(jiao)也(ye)具備良好的(de)保護性。

2、靜電(dian)損壞，很多廠家(jia)一直(zhi)強調(diao)防靜電(dian)保(bao)護，其(qi)主(zhu)要目的就在(zai)于(yu)保(bao)護LED燈珠(zhu)使用(yong)過程(cheng)中(zhong)因為靜電(dian)的緣(yuan)故(gu)造成漏電(dian)，所以在(zai)包裝上廠家(jia)一般都采用(yong)防靜電(dian)鋁(lv)薄袋(dai)。

3、晶片本身漏電(dian)，發光(guang)晶片本身漏電(dian)有很多原因，廠家出廠前都有嚴格的檢測(ce)，所以幾率很小，除此之外(wai)就是使(shi)用過程(cheng)中的其他原因造成晶片漏電(dian)。

4、使用操作(zuo)不當造成的(de)(de)漏電，這種情況是最(zui)多的(de)(de)，但是具體原(yuan)因(yin)也是各種因(yin)素引(yin)起的(de)(de)。

LED漏電原因的分析

1 芯片受到沾(zhan)污引(yin)起漏電

LED芯(xin)(xin)(xin)片(pian)是(shi)非常(chang)(chang)小的(de)(de)(de)(de)，灰塵(chen)等(deng)易對(dui)(dui)它產(chan)(chan)(chan)生(sheng)遮蔽作(zuo)(zuo)用(yong)，最(zui)重要的(de)(de)(de)(de)是(shi)灰塵(chen)、水汽、各種雜質離(li)子會附著與芯(xin)(xin)(xin)片(pian)表面(mian)，不(bu)(bu)僅(jin)會在(zai)表面(mian)對(dui)(dui)芯(xin)(xin)(xin)片(pian)內部產(chan)(chan)(chan)生(sheng)作(zuo)(zuo)用(yong)，還會擴散(san)進入(ru)芯(xin)(xin)(xin)片(pian)內部產(chan)(chan)(chan)生(sheng)作(zuo)(zuo)用(yong)。比如(ru)，銅離(li)子、鈉離(li)子都(dou)很(hen)(hen)容易擴散(san)進入(ru)半(ban)導體材(cai)料中，非常(chang)(chang)微小的(de)(de)(de)(de)數量就可以使半(ban)導體器件的(de)(de)(de)(de)性能嚴重惡化(hua)。對(dui)(dui)于半(ban)導體器件的(de)(de)(de)(de)制造，通(tong)常(chang)(chang)都(dou)要求(qiu)(qiu)有(you)(you)凈(jing)化(hua)等(deng)級非常(chang)(chang)高的(de)(de)(de)(de)潔(jie)凈(jing)廠(chang)(chang)房。可以考察(cha)一下LED封(feng)裝廠(chang)(chang)，上千家(jia)(jia)之中有(you)(you)幾家(jia)(jia)的(de)(de)(de)(de)廠(chang)(chang)房能有(you)(you)什(shen)么樣的(de)(de)(de)(de)潔(jie)凈(jing)等(deng)級?絕大多數都(dou)是(shi)能與大氣直接相通(tong)的(de)(de)(de)(de)房間，根本(ben)談不(bu)(bu)上凈(jing)化(hua)。雖然有(you)(you)人(ren)會說，“我們的(de)(de)(de)(de)廠(chang)(chang)房沒(mei)有(you)(you)灰塵(chen)，很(hen)(hen)潔(jie)凈(jing)”，可是(shi)，潔(jie)凈(jing)程(cheng)度(du)不(bu)(bu)是(shi)用(yong)眼睛來看(kan)的(de)(de)(de)(de)!眼睛是(shi)根本(ben)看(kan)不(bu)(bu)到(dao)芯(xin)(xin)(xin)片(pian)生(sheng)產(chan)(chan)(chan)和封(feng)裝要求(qiu)(qiu)的(de)(de)(de)(de)潔(jie)凈(jing)程(cheng)度(du)的(de)(de)(de)(de)，必須是(shi)用(yong)專門的(de)(de)(de)(de)儀器來檢測。不(bu)(bu)僅(jin)僅(jin)要求(qiu)(qiu)廠(chang)(chang)房要達到(dao)要求(qiu)(qiu)的(de)(de)(de)(de)潔(jie)凈(jing)度(du)，對(dui)(dui)涉及到(dao)芯(xin)(xin)(xin)片(pian)裸露(lu)的(de)(de)(de)(de)工(gong)(gong)序，工(gong)(gong)作(zuo)(zuo)人(ren)員要穿凈(jing)化(hua)工(gong)(gong)作(zuo)(zuo)服，戴(dai)工(gong)(gong)作(zuo)(zuo)帽(mao)，戴(dai)口罩，工(gong)(gong)作(zuo)(zuo)人(ren)員不(bu)(bu)許涂化(hua)妝品等(deng)。這(zhe)些個嚴苛生(sheng)產(chan)(chan)(chan)條件，目前對(dui)(dui)LED封(feng)裝廠(chang)(chang)來講，不(bu)(bu)是(shi)想(xiang)不(bu)(bu)到(dao)，就是(shi)不(bu)(bu)愿做。不(bu)(bu)愿做的(de)(de)(de)(de)原因非常(chang)(chang)簡單，成本(ben)上的(de)(de)(de)(de)增加無法接受——競爭太激烈。封(feng)裝廠(chang)(chang)房達不(bu)(bu)到(dao)要求(qiu)(qiu)的(de)(de)(de)(de)潔(jie)凈(jing)程(cheng)度(du)，那么，LED的(de)(de)(de)(de)質量問題就來了。

早期的LED芯片以及現(xian)在(zai)很多廠家的芯片，都沒有在(zai)芯片的側面做保護(hu)層。現(xian)在(zai)國外一(yi)些(xie)芯片廠商已經開(kai)始在(zai)芯片的側面做保護(hu)層了(le)。但是(shi)，現(xian)在(zai)的保護(hu)層一(yi)般是(shi)采用二氧(yang)化硅材料，而且厚度很薄，保護(hu)能(neng)力是(shi)有限(xian)的。在(zai)潔凈度很差的封裝廠，仍然會由(you)于(yu)沾污造(zao)成(cheng)漏電(dian)現(xian)象。

1.1 芯片側面(mian)沒有(you)做(zuo)鈍化

很多芯(xin)片(pian)(pian)由于各種因素，沒有對芯(xin)片(pian)(pian)的側面(mian)做鈍化保護，使(shi)得芯(xin)片(pian)(pian)劃片(pian)(pian)后，PN結在側面(mian)裸(luo)露于空氣中。

2. 銀膠過(guo)高造成漏電

這個問(wen)題(ti)在LED封(feng)裝業中已是常識(shi)性的、看得見的問(wen)題(ti)了，無需(xu)我多啰(luo)嗦了。

3. 打線偏焊造(zao)成漏電

這個問題(ti)在(zai)LED封裝業中也(ye)是常識性的、看得(de)見的問題(ti)了，也(ye)無需我多(duo)啰嗦了。

4. 應力造成漏電

應(ying)力(li)(li)(li)，往(wang)(wang)往(wang)(wang)是看不(bu)見的(de)，若對(dui)材(cai)(cai)(cai)料的(de)一(yi)些基本性(xing)質不(bu)了(le)解(jie)，則不(bu)太好理解(jie)這個問題。其實(shi)，應(ying)力(li)(li)(li)相(xiang)對(dui)于(yu)日常(chang)可(ke)見的(de)比(bi)如推土(tu)(tu)機推土(tu)(tu)那樣(yang)大的(de)力(li)(li)(li)相(xiang)比(bi)，它(ta)是很難看得見的(de)作用力(li)(li)(li)而(er)(er)已。它(ta)往(wang)(wang)往(wang)(wang)是由于(yu)材(cai)(cai)(cai)料的(de)熱(re)脹冷縮而(er)(er)產生。應(ying)力(li)(li)(li)的(de)影(ying)響(xiang)往(wang)(wang)往(wang)(wang)是在兩(liang)(liang)種(zhong)(zhong)材(cai)(cai)(cai)料的(de)接(jie)(jie)(jie)觸(chu)(chu)方面。應(ying)力(li)(li)(li)作用可(ke)以(yi)是直接(jie)(jie)(jie)壓力(li)(li)(li)，也(ye)可(ke)以(yi)是與材(cai)(cai)(cai)料接(jie)(jie)(jie)觸(chu)(chu)面平行(xing)的(de)橫(heng)向剪(jian)切力(li)(li)(li)。舉一(yi)個簡單的(de)例子，在兩(liang)(liang)根鐵(tie)(tie)軌之間(jian)是有一(yi)段(duan)間(jian)隙的(de)，如果將這個間(jian)隙留的(de)很小，當溫度升高時，兩(liang)(liang)段(duan)鐵(tie)(tie)軌的(de)端面就(jiu)會(hui)接(jie)(jie)(jie)觸(chu)(chu)，甚(shen)至(zhi)擠(ji)壓變形(xing)。這就(jiu)是應(ying)力(li)(li)(li)作用。當兩(liang)(liang)種(zhong)(zhong)不(bu)同(tong)的(de)材(cai)(cai)(cai)料粘結接(jie)(jie)(jie)觸(chu)(chu)時，當溫度發生變化(hua)，若兩(liang)(liang)種(zhong)(zhong)材(cai)(cai)(cai)料的(de)熱(re)膨脹系數不(bu)同(tong)，在接(jie)(jie)(jie)觸(chu)(chu)面由于(yu)延(yan)伸(shen)或收縮尺度不(bu)同(tong)，相(xiang)互間(jian)產生拉力(li)(li)(li)，這就(jiu)是橫(heng)向的(de)剪(jian)切應(ying)力(li)(li)(li)。

在LED中(zhong)，有不(bu)(bu)(bu)同的(de)(de)材料，熱膨(peng)脹系(xi)(xi)數是(shi)(shi)不(bu)(bu)(bu)同的(de)(de)。在溫度反復(fu)變(bian)化的(de)(de)過程(cheng)中(zhong)，各(ge)物質不(bu)(bu)(bu)可(ke)能回(hui)復(fu)到(dao)它們(men)最初接觸時(shi)的(de)(de)狀態，相互間(jian)會保持有一定(ding)的(de)(de)應力(li)。但不(bu)(bu)(bu)一定(ding)會有害。只有當膨(peng)脹系(xi)(xi)數相差太大(da)、工藝條件不(bu)(bu)(bu)合適時(shi)，就可(ke)能留下很(hen)(hen)大(da)的(de)(de)應力(li)。這個應力(li)嚴(yan)(yan)重的(de)(de)會壓(ya)壞芯片，使芯片破損，造成漏電、部分區(qu)域裂開而不(bu)(bu)(bu)亮(liang)，嚴(yan)(yan)重的(de)(de)徹底開路不(bu)(bu)(bu)亮(liang)。應力(li)不(bu)(bu)(bu)是(shi)(shi)很(hen)(hen)大(da)時(shi)，有時(shi)也會產生(sheng)嚴(yan)(yan)重的(de)(de)后(hou)果。

原本(ben)在LED的(de)側(ce)面(mian)就存在著(zhu)懸(xuan)掛鍵(jian)，應力的(de)作用，使得表面(mian)原子發(fa)(fa)生微位移(yi)，這些懸(xuan)掛鍵(jian)的(de)電場更加處于一種(zhong)不平衡狀態，從而造成端面(mian)PN結處的(de)能級狀態發(fa)(fa)生改變，造成漏(lou)電。

5. 使(shi)用不當造成漏電(dian)

這種狀況一般(ban)較少發生。當較高的反向電壓加給(gei)LED，可(ke)能損壞PN結(jie)，造成漏電。

這(zhe)種損(sun)壞，和靜電損(sun)壞的(de)機理是(shi)(shi)相(xiang)同(tong)的(de)。如果不是(shi)(shi)當事人(ren)自己確認，封裝廠的(de)工(gong)程師單(dan)憑損(sun)壞的(de)樣品來看，是(shi)(shi)很難分辨的(de)。

6. 芯片(pian)本身(shen)漏電

通(tong)常，這種情況也是較少發(fa)生。除非芯(xin)片的次品出廠。

一般來講(jiang)，芯(xin)(xin)片在(zai)制造廠(chang)是(shi)(shi)(shi)不(bu)容易受到沾污的。但(dan)是(shi)(shi)(shi)，在(zai)芯(xin)(xin)片的后續分選(xuan)、包裝(zhuang)(zhuang)時，是(shi)(shi)(shi)有可能發生(sheng)沾污的。本人看到過某芯(xin)(xin)片廠(chang)的后續分選(xuan)、包裝(zhuang)(zhuang)車間環境就是(shi)(shi)(shi)沒(mei)有凈(jing)化等級的普通(tong)廠(chang)房。

7. 工藝不當，使得芯片(pian)開裂

芯片(pian)底部膠體不均(jun)勻，或(huo)焊(han)盤(pan)下(xia)面有空洞，打線時可能損傷芯片(pian)產(chan)生漏電或(huo)失效。 焊(han)線機調整不當，打傷芯片(pian)，產(chan)生漏電或(huo)失效。

8. 靜電(dian)問題

在LED行業，似乎將(jiang)靜電當(dang)成了損壞LED的頭號大敵。但本人卻不這么認為。相(xiang)反，將(jiang)它當(dang)成次要問題。

對(dui)于靜電對(dui)LED的損壞問題，本人(ren)在(zai)一(yi)些(xie)(xie)論(lun)壇里(li)有談過【7】。現在(zai)將那些(xie)(xie)內容(rong)搬(ban)過來，并(bing)加以(yi)補充(chong)，以(yi)便(bian)大家(jia)閱讀與(yu)了(le)解(jie)。

8.1 靜電(dian)的(de)產生機理

通常(chang)，靜電的(de)產生(sheng)是由于摩(mo)擦或感應而產生(sheng)。

摩(mo)(mo)(mo)擦靜(jing)電(dian)(dian)是由(you)(you)于(yu)兩(liang)個物(wu)體接觸(chu)摩(mo)(mo)(mo)擦或分(fen)離過(guo)(guo)程中(zhong)產生電(dian)(dian)荷的(de)(de)(de)移動(dong)(dong)而(er)(er)(er)產生。導(dao)體間的(de)(de)(de)摩(mo)(mo)(mo)擦留下(xia)的(de)(de)(de)靜(jing)電(dian)(dian)通常(chang)比較弱，這是由(you)(you)于(yu)導(dao)體的(de)(de)(de)導(dao)電(dian)(dian)能(neng)(neng)力(li)強，摩(mo)(mo)(mo)擦產生的(de)(de)(de)離子(zi)會(hui)在摩(mo)(mo)(mo)擦過(guo)(guo)程中(zhong)及(ji)終止時很(hen)快(kuai)運動(dong)(dong)到(dao)一起而(er)(er)(er)中(zhong)和。而(er)(er)(er)絕(jue)緣體摩(mo)(mo)(mo)擦后(hou)，可能(neng)(neng)會(hui)產生較高的(de)(de)(de)靜(jing)電(dian)(dian)電(dian)(dian)壓，但(dan)是電(dian)(dian)荷量卻很(hen)小。這是由(you)(you)于(yu)絕(jue)緣體本身的(de)(de)(de)物(wu)理結(jie)構(gou)決定的(de)(de)(de)。絕(jue)緣體的(de)(de)(de)分(fen)子(zi)結(jie)構(gou)中(zhong)，電(dian)(dian)子(zi)很(hen)難脫離原子(zi)核的(de)(de)(de)束縛自由(you)(you)移動(dong)(dong)，所(suo)以，摩(mo)(mo)(mo)擦結(jie)果也只能(neng)(neng)產生少(shao)量的(de)(de)(de)分(fen)子(zi)或原子(zi)電(dian)(dian)離。

感(gan)應(ying)靜電是物(wu)體(ti)處于電場之中，受電磁場的作用，物(wu)體(ti)中的電子發生(sheng)移動(dong)而形(xing)成電場。感(gan)應(ying)靜電一般只能(neng)在導體(ti)上產生(sheng)。空(kong)間(jian)電磁場對絕緣體(ti)的作用可以忽略(lve)。

8.2 靜電(dian)的放電(dian)機理

220V的(de)市電(dian)(dian)可以打死(si)人(ren)，可人(ren)們身(shen)上(shang)上(shang)千伏(fu)的(de)電(dian)(dian)壓卻打不死(si)人(ren)，是何道理? 電(dian)(dian)容兩端的(de)電(dian)(dian)壓滿足下列(lie)公(gong)式：

U=Q/C

根據這個公式(shi)可以知(zhi)道，當電容(rong)量很(hen)小時，很(hen)少的(de)電荷量，就(jiu)會產生(sheng)很(hen)高的(de)電壓。

通(tong)常我們的(de)(de)身(shen)體(ti)、身(shen)邊的(de)(de)物(wu)體(ti)，電容都非(fei)常小，當產(chan)生(sheng)電荷后(hou)，很(hen)少的(de)(de)電荷量，也會產(chan)生(sheng)很(hen)高的(de)(de)電壓。

由于(yu)電荷量(liang)很(hen)少，放電時(shi)(shi)，形成(cheng)的電流(liu)非常小，時(shi)(shi)間(jian)非常短，電壓不能維持，極短的時(shi)(shi)間(jian)就(jiu)降下來。

由于人(ren)(ren)體不是絕緣(yuan)體，所以，身體各處(chu)積累的靜電(dian)(dian)荷，在有放(fang)電(dian)(dian)通路的情況(kuang)下，都會匯集過來，所以感(gan)覺(jue)電(dian)(dian)流大些，有電(dian)(dian)擊的感(gan)覺(jue)。人(ren)(ren)體、金屬物品等導體在產生靜電(dian)(dian)后，放(fang)電(dian)(dian)電(dian)(dian)流會比較(jiao)大。

對于絕緣性(xing)能(neng)好的(de)材料，一個是(shi)(shi)產生(sheng)的(de)電(dian)(dian)荷量非(fei)常小，另(ling)一方面，產生(sheng)的(de)電(dian)(dian)荷，很(hen)難流動。電(dian)(dian)壓雖(sui)然高，但某處(chu)有放電(dian)(dian)通(tong)路時(shi)，只是(shi)(shi)接觸點及附近極小范圍內的(de)電(dian)(dian)荷可以(yi)流動放電(dian)(dian)，非(fei)接觸點的(de)電(dian)(dian)荷則不能(neng)放電(dian)(dian)(誰叫它是(shi)(shi)絕緣體呢)。故而，就是(shi)(shi)有上萬伏的(de)電(dian)(dian)壓，放電(dian)(dian)能(neng)量也是(shi)(shi)微(wei)乎其微(wei)的(de)。

8.3 靜(jing)電對電子元器件的(de)危害

靜電會對LED有危(wei)害(hai)，并(bing)不是LED獨(du)有的“專利”，就(jiu)是用硅材料制造的常用的二極管、三極管，也都會受到威脅。甚至建(jian)筑、樹木、動物都可(ke)能被靜電損害(hai)(雷電就(jiu)是一種靜電，我們這里就(jiu)不去考慮它了(le))。

那么，靜電(dian)(dian)是怎么對電(dian)(dian)子元件(jian)損害的(de)呢?我也(ye)不要扯得太遠(yuan)，就只講半導體器件(jian)的(de)問題，而(er)且就局(ju)限于二極(ji)管、三極(ji)管、IC、LED方(fang)面。(否則會啰(luo)嗦太多沖淡(dan)主題)。

電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)對半導(dao)體元器件的(de)(de)損壞，最(zui)終是(shi)有(you)(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)參(can)與(yu)。在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)作用下，由(you)于熱(re)而損壞器件。要(yao)有(you)(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)，就要(yao)有(you)(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)。但(dan)是(shi)，半導(dao)體二極管有(you)(you)PN結(jie)(jie)(jie)，無論是(shi)正(zheng)向(xiang)(xiang)還是(shi)反向(xiang)(xiang)，PN結(jie)(jie)(jie)都會(hui)有(you)(you)阻(zu)擋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)一個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)范圍。正(zheng)向(xiang)(xiang)勢壘低，反向(xiang)(xiang)勢壘則要(yao)高(gao)很多。在(zai)(zai)一個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路中(zhong)，哪(na)里的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)大(da)(da)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)就在(zai)(zai)哪(na)里集中(zhong)。但(dan)就來看(kan)LED，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)正(zheng)向(xiang)(xiang)加(jia)(jia)給(gei)LED時(shi)(shi)，當(dang)外(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)小(xiao)(xiao)于二極管的(de)(de)閾值(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(大(da)(da)小(xiao)(xiao)與(yu)材料禁帶寬度對應(ying))，沒有(you)(you)正(zheng)向(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)全(quan)部(bu)加(jia)(jia)在(zai)(zai)PN結(jie)(jie)(jie)上(shang)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)反向(xiang)(xiang)加(jia)(jia)給(gei)LED時(shi)(shi)，當(dang)外(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)小(xiao)(xiao)于LED的(de)(de)反向(xiang)(xiang)擊穿電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)也(ye)是(shi)全(quan)部(bu)加(jia)(jia)在(zai)(zai)PN結(jie)(jie)(jie)上(shang)，此(ci)時(shi)(shi)，LED的(de)(de)虛焊點也(ye)罷(ba)，支架也(ye)罷(ba)、P區也(ye)罷(ba)、N區也(ye)罷(ba)，統(tong)統(tong)都沒有(you)(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)降(jiang)!因為(wei)沒有(you)(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。當(dang)著PN結(jie)(jie)(jie)擊穿后，外(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)才會(hui)由(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路上(shang)的(de)(de)所有(you)(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)分(fen)擔(dan)。哪(na)個地方電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)大(da)(da)，哪(na)個部(bu)分(fen)承擔(dan)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)就高(gao)。就LED而言，自然是(shi)PN結(jie)(jie)(jie)承擔(dan)了大(da)(da)部(bu)分(fen)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)。在(zai)(zai)PN結(jie)(jie)(jie)上(shang)產(chan)生的(de)(de)熱(re)功(gong)率就是(shi)它上(shang)面的(de)(de)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)降(jiang)乘以電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)值(zhi)。若是(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)值(zhi)不加(jia)(jia)限(xian)制，過(guo)高(gao)的(de)(de)熱(re)量就會(hui)將PN結(jie)(jie)(jie)燒壞，PN結(jie)(jie)(jie)失去(qu)作用而穿通。

IC為什么(me)會(hui)(hui)比(bi)較(jiao)怕靜(jing)(jing)電(dian)(dian)(dian)，因為，IC中(zhong)的(de)(de)每個元(yuan)件(jian)的(de)(de)面積非(fei)常(chang)(chang)(chang)小(xiao)(xiao)，每個元(yuan)件(jian)的(de)(de)寄生(sheng)(sheng)電(dian)(dian)(dian)容(rong)(rong)也(ye)(ye)就(jiu)非(fei)常(chang)(chang)(chang)小(xiao)(xiao)(往往電(dian)(dian)(dian)路(lu)功(gong)能就(jiu)要求寄生(sheng)(sheng)電(dian)(dian)(dian)容(rong)(rong)非(fei)常(chang)(chang)(chang)小(xiao)(xiao))，所(suo)以(yi)，少量的(de)(de)靜(jing)(jing)電(dian)(dian)(dian)電(dian)(dian)(dian)荷就(jiu)會(hui)(hui)產生(sheng)(sheng)很(hen)(hen)(hen)(hen)高的(de)(de)靜(jing)(jing)電(dian)(dian)(dian)電(dian)(dian)(dian)壓，而(er)且每個元(yuan)件(jian)的(de)(de)功(gong)率(lv)耐量通(tong)常(chang)(chang)(chang)也(ye)(ye)很(hen)(hen)(hen)(hen)小(xiao)(xiao)，所(suo)以(yi)，靜(jing)(jing)電(dian)(dian)(dian)放電(dian)(dian)(dian)就(jiu)很(hen)(hen)(hen)(hen)容(rong)(rong)易(yi)損(sun)壞IC。但是(shi)通(tong)常(chang)(chang)(chang)的(de)(de)分立(li)元(yuan)件(jian)，如普通(tong)的(de)(de)小(xiao)(xiao)功(gong)率(lv)二極(ji)管、小(xiao)(xiao)功(gong)率(lv)三(san)(san)極(ji)管都不是(shi)非(fei)常(chang)(chang)(chang)怕靜(jing)(jing)電(dian)(dian)(dian)，因為它們(men)芯(xin)片(pian)的(de)(de)面積比(bi)較(jiao)大(da)，寄生(sheng)(sheng)電(dian)(dian)(dian)容(rong)(rong)也(ye)(ye)比(bi)較(jiao)大(da)，一般的(de)(de)靜(jing)(jing)定不容(rong)(rong)易(yi)在(zai)它們(men)上面積累高電(dian)(dian)(dian)壓。小(xiao)(xiao)功(gong)率(lv)的(de)(de)MOS管，由于柵極(ji)氧(yang)化層(ceng)很(hen)(hen)(hen)(hen)薄，寄生(sheng)(sheng)電(dian)(dian)(dian)容(rong)(rong)小(xiao)(xiao)，所(suo)以(yi)很(hen)(hen)(hen)(hen)容(rong)(rong)易(yi)遭(zao)靜(jing)(jing)電(dian)(dian)(dian)損(sun)壞，通(tong)常(chang)(chang)(chang)會(hui)(hui)在(zai)封裝完成后(hou)將(jiang)三(san)(san)個電(dian)(dian)(dian)極(ji)短(duan)路(lu)后(hou)出廠(chang)。使用中(zhong)也(ye)(ye)常(chang)(chang)(chang)要求在(zai)焊接完成后(hou)再(zai)去掉短(duan)路(lu)線。而(er)大(da)功(gong)率(lv)的(de)(de)MOS管，由于芯(xin)片(pian)面積大(da)，一般的(de)(de)靜(jing)(jing)電(dian)(dian)(dian)也(ye)(ye)不會(hui)(hui)損(sun)壞它們(men)。所(suo)以(yi)你會(hui)(hui)看到(dao)，現(xian)在(zai)功(gong)率(lv)MOS管的(de)(de)三(san)(san)個電(dian)(dian)(dian)極(ji)是(shi)沒有(you)短(duan)路(lu)線保護的(de)(de)。(早期制造廠(chang)還是(shi)將(jiang)它們(men)短(duan)路(lu)后(hou)出廠(chang)的(de)(de))

LED實際(ji)就是(shi)有個二極管，它(ta)的(de)面積相對(dui)IC內(nei)的(de)每個元件(jian)來(lai)講，是(shi)非(fei)常大(da)的(de)。所(suo)以(yi)LED的(de)寄生(sheng)電(dian)容相對(dui)來(lai)說也是(shi)比較大(da)的(de)。所(suo)以(yi)，一般場合的(de)靜電(dian)并(bing)不能(neng)損壞LED。

一(yi)般場合的(de)靜(jing)(jing)電(dian)，尤其(qi)是絕緣體(ti)上產(chan)生的(de)靜(jing)(jing)電(dian)，電(dian)壓會(hui)很(hen)(hen)高，但放(fang)電(dian)電(dian)荷量極微，而(er)且放(fang)電(dian)電(dian)流(liu)(liu)(liu)持續時間很(hen)(hen)短。而(er)導體(ti)上感應(ying)的(de)靜(jing)(jing)電(dian)，電(dian)壓可(ke)能不是很(hen)(hen)高，但是放(fang)電(dian)電(dian)流(liu)(liu)(liu)卻可(ke)能很(hen)(hen)大(da)，而(er)且往往是持續的(de)電(dian)流(liu)(liu)(liu)。這樣對電(dian)子元件的(de)危(wei)害就非常大(da)。

8.4 為什么說靜電對LED的損害是不常發生的呢

先來看一(yi)(yi)個試驗現象。一(yi)(yi)塊金(jin)屬(shu)鐵板上帶(dai)有(you)500V的(de)(de)靜(jing)電(dian)(dian)(dian)，將(jiang)LED放到金(jin)屬(shu)板上(放的(de)(de)方(fang)法(fa)要注意，避免下述的(de)(de)問題發生)，大家說(shuo)LED會被(bei)損壞嗎?這里(li)，LED要被(bei)損壞，通常(chang)應該是(shi)(shi)被(bei)加(jia)上大于(yu)其擊穿電(dian)(dian)(dian)壓(ya)(ya)的(de)(de)電(dian)(dian)(dian)壓(ya)(ya)，也(ye)就是(shi)(shi)說(shuo)LED的(de)(de)兩個電(dian)(dian)(dian)極(ji)要同時接(jie)觸金(jin)屬(shu)板，并具有(you)大于(yu)擊穿電(dian)(dian)(dian)壓(ya)(ya)的(de)(de)電(dian)(dian)(dian)壓(ya)(ya)。由(you)于(yu)鐵板是(shi)(shi)良導(dao)體(ti)，其上各處的(de)(de)感(gan)應電(dian)(dian)(dian)壓(ya)(ya)相等，所謂(wei)500V的(de)(de)電(dian)(dian)(dian)壓(ya)(ya)是(shi)(shi)相對(dui)于(yu)地(di)而言的(de)(de)，所以，LED兩電(dian)(dian)(dian)極(ji)間是(shi)(shi)沒有(you)電(dian)(dian)(dian)壓(ya)(ya)的(de)(de)，自然(ran)也(ye)就不會受(shou)到任何損傷了。除非，你將(jiang)LED的(de)(de)一(yi)(yi)個電(dian)(dian)(dian)極(ji)接(jie)觸鐵板，另一(yi)(yi)個電(dian)(dian)(dian)極(ji)你用(yong)導(dao)體(ti)(未戴絕緣手套的(de)(de)手或導(dao)線)連接(jie)到地(di)或其它(ta)導(dao)體(ti)上。

上面(mian)的(de)(de)試驗現象提示(shi)我們，LED在(zai)靜(jing)電(dian)(dian)場中時(shi)，必須是一(yi)(yi)個電(dian)(dian)極接觸靜(jing)電(dian)(dian)體，另(ling)一(yi)(yi)個電(dian)(dian)極要(yao)接觸地或其(qi)它(ta)導(dao)體才可(ke)能受損。在(zai)實(shi)際生產和應用中，以(yi)LED那(nei)么小的(de)(de)體積，很少(shao)有(you)機會發(fa)生那(nei)樣的(de)(de)事(shi)情，尤其(qi)是批(pi)量發(fa)生那(nei)樣的(de)(de)事(shi)情。偶然(ran)的(de)(de)事(shi)件是可(ke)能的(de)(de)。比如(ru)，LED處(chu)于靜(jing)電(dian)(dian)體上，且一(yi)(yi)個電(dian)(dian)極接觸到靜(jing)電(dian)(dian)體，另(ling)一(yi)(yi)個電(dian)(dian)極剛好是懸空的(de)(de)，此時(shi)有(you)人去(qu)觸及了(le)懸空的(de)(de)那(nei)個電(dian)(dian)極，就可(ke)能損傷(shang)LED。

上面的現象告訴我們，靜電問題(ti)也不(bu)是(shi)可以忽視的。 靜電放(fang)電是(shi)要有導電回路的，不(bu)是(shi)有靜電就有損害。

上(shang)面的(de)現象(xiang)還(huan)提示我(wo)們，當(dang)著僅有(you)極少量(liang)的(de)漏電(dian)問(wen)(wen)題(ti)發生，可以考慮靜電(dian)偶(ou)然損壞(huai)問(wen)(wen)題(ti)。若是(shi)大(da)量(liang)發生，則(ze)更多的(de)可能(neng)是(shi)芯片沾污或應(ying)力(li)的(de)問(wen)(wen)題(ti)。

9. 其它(ta)原因(yin)引起漏電

本(ben)人曾遇到(dao)過這樣(yang)的(de)漏電(dian)(dian)狀況(kuang)，LED被封裝與一(yi)個殼體(ti)中，LED周(zhou)圍灌有(you)軟(ruan)膠(jiao)以防水。可是(shi)從LED的(de)引線上測到(dao)有(you)嚴重的(de)漏電(dian)(dian)。將周(zhou)圍的(de)灌封膠(jiao)去除后，漏電(dian)(dian)消(xiao)失(shi)。這里其(qi)實并不是(shi)LED漏電(dian)(dian)，而是(shi)灌封膠(jiao)有(you)問題。

深圳(zhen)led燈珠是什(shen)么(me)原因(yin)漏電的？

1、深(shen)圳led燈珠(zhu)基礎橡(xiang)膠太厚漏電了。

2、深圳led燈珠技術不當(dang)導(dao)致(zhi)芯(xin)片(pian)破(po)裂等(deng)，例(li)如，燈珠在(zai)焊接(jie)線(xian)時焊接(jie)線(xian)機(ji)操(cao)作不當(dang)，導(dao)致(zhi)磁噴嘴焊接(jie)線(xian)時壓力過大，造(zao)成芯(xin)片(pian)損壞，導(dao)致(zhi)芯(xin)片(pian)破(po)裂等(deng)。3、深圳led燈珠靜電(dian)引起串(chuan)珠漏電(dian)，靜電(dian)通(tong)常是摩擦(ca)引起的，這也(ye)是比較容易(yi)漏電(dian)的原因，所以生產(chan)串(chuan)珠時必(bi)須要求員工穿上(shang)靜電(dian)服和靜電(dian)帽，盡量減少靜電(dian)的產(chan)生。

4、深圳led燈珠晶圓本身(shen)有(you)缺陷，導致(zhi)漏電。

5、深圳led燈珠(zhu)晶(jing)圓(yuan)被污染(ran)過，這(zhe)是(shi)經常(chang)發(fa)生的問題(ti)，也是(shi)經常(chang)發(fa)生的問題(ti)。其原因是(shi)在拿芯(xin)片時運用(yong)時不(bu)注(zhu)意(yi)，讓芯(xin)片沾上灰塵、水蒸(zheng)氣等東西(xi)，LED芯(xin)片是(shi)一種非常(chang)細的東西(xi)，稍不(bu)注(zhu)意(yi)就會(hui)破壞珠(zhu)子的構造(zao)，串珠(zhu)就會(hui)漏電或死。所以(yi)這(zhe)要求工(gong)廠的建筑運用(yong)無塵車間，取芯(xin)片時帶防靜電手套，操(cao)作人員不(bu)允許化裝(zhuang)，作業時應(ying)卷頭發(fa)等一系列(lie)要求。

6、深圳led燈珠焊(han)(han)接(jie)(jie)線(xian)(xian)時，線(xian)(xian)沒有(you)焊(han)(han)接(jie)(jie)，燈珠漏(lou)電。比(bi)如說，線(xian)(xian)被焊(han)(han)接(jie)(jie)、被焊(han)(han)接(jie)(jie)、焊(han)(han)接(jie)(jie)線(xian)(xian)的拉伸(shen)力設定(ding)得不適(shi)當，這(zhe)(zhe)些都表示串(chuan)珠漏(lou)電的現象，但是這(zhe)(zhe)個問題(ti)也經常發(fa)生。