<P>用ZEMAX设计了一个简单的聚焦镜,聚焦镜由一个正镜和一个负镜组成,单色平行光入射,零视场,将球差优化为零,又因为无轴外物点,所以彗差,畸变,像散也为零.但焦点前某个位置的斑点图显示光斑边缘光线密度大于中心光线密度, 如图所示.
<img src="data/attachment/forum/dvbbs/2004-5/2004526151916962.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'data/attachment/forum/dvbbs/2004-5/2004526151916962.jpg\');}" onmousewheel="return imgzoom(this);" alt="" />
用实际的镜片验证,这个位置确实存在,在这个位置光斑边缘能量大于中心的能量.</P>
<P>请问这种情况是怎么造成的?怎么解决?</P>