图形显示设备-Read课件.ppt
2.2 图形显示设备,2.2.1 阴极射线管(CRT)阴极射线管、彩色阴极射线管2.2.2 CRT图形显示器随机扫描、直视存储管、光栅扫描2.2.3 平板显示器（flat-panel display）*液晶显示器、等离子体显示板、薄片光电显示器、发光二极管显示器、激光显示器2.2.4 三维观察设备,2.2.1 阴极射线管(CRT),(一)阴极射线管(二)彩色阴极射线管,(一)阴极射线管,CRTCathode Ray TubeAnode,从外形上看：管颈部分、锥体部分、屏幕部分 从结构上看：电子枪、偏转系统、荧光屏,Flash 演示,1.电子枪,阴极,栅极,加速阳极,聚焦阳极截止电压:栅极负压使电子束电子流为0时的电压值.,2.偏转系统,磁偏转电偏转,电偏转,灯,丝,阴,极,加,速,极,控,制,栅,聚,焦,极,加,速,极,荧,光,屏,图2-7 CRT的构造（电偏转）,水,平,偏,转,板,垂,直,偏,转,板,3.荧光屏(Phosphor Screen),余辉特性-p28余辉时间,(二)彩色阴极射线管,三基色原则:红(Red,R)绿(Green,G)蓝(Blue,B)物理三基色色域-红,黄,蓝,彩色阴极射线管,荫罩式彩色显象管Shadow Mask 穿透式彩色显示 Beam-Penetration,荫罩式彩色显象管,主要结构：三色荧光屏三支电子枪荫罩板,三色荧光屏,荫罩板,三支电子枪,Flash 演示,荧光点的面积比电子束截面大只有15%左右的电子到达屏幕,改进:黑底荫罩管,彩色显象管必须满足的要求,色纯会聚白色平衡 p31,2.穿透式彩色显示原理,红,橙,黄,绿,2.2.2 CRT图形显示器,随机扫描的图形显示器直视存储管图形显示器光栅扫描的图形显示器,1.随机扫描的图形显示器,向量(vector)显示器笔划(Stroke writing)显示器Random-ScanFlash 演示,2.直视存储管图形显示器,直视存储管DVST（direct-view storage tube）,存储管显示器结构示意图,Flash 演示,屏,幕,存储栅,收集栅,写电,子抢,电子流,读出电子抢,写阴极,3.光栅扫描的图形显示器,Raster-Scan Displays,Flash 演示,几个概念,刷新速率：60到80帧/秒(60Hz或80Hz)水平回扫(Horizontal Retrace):行扫描垂直回扫(Vertical Retrace):场扫描(帧扫描)逐行扫描和隔行(interlaced)扫描,像素 pixel或pel,Picture Element的简写Each screen spot that can be illuminated by the electron beam is referred to as a pixel.,帧 Frame,Frame refers to the total screen area.,刷新缓冲存储器 Refresh Buffer帧缓冲存储器Frame Buffer,00000000000000000000000000000000000000011111100000000000111111000000000001111110000000000000000000000000000000000000000,帧缓存,显示器,The Depth of the Frame Buffer,The number of bits that are used for each pixel.,举例,one-bit-deep frame bufferallows 2 colors 8-bit-deep frame bufferallows 28(=256)colors,Full-color systemTrue color system,24 or more bits per pixel,位图 Bitmap,A frame buffer with one bit per pixel is called bitmap,Pixmap,A frame buffer with multiple bits per pixel is a pixmap.,分辨率 Resolution,Resolution is the number of pixel positions that can be plotted.,屏幕长宽比Aspect Ratio,水平点数和垂直点数之比,扫描转换 Scan-Conversion,象素信息从应用程序转换,并放入帧缓冲区的过程,Raster scan,Random scan,走样与反走样,2.2.3 平板显示器（flat-panel display）*,液晶显示器等离子体显示板薄片光电显示器发光二极管显示器激光显示器,2.2.4 三维观察设备*,方法一:采用从变焦距的柔性震动镜面反射CRT图象的技术方法二:显示具有立体感的视图,一.从变焦距的柔性震动镜面反射CRT图象,二.显示具立体感的视图,Display stereoscopic view of the objectProviding different view of each eye.,三种实现方法,利用不同的刷新周期交替地显示两视图将屏幕分半使用头盔式结构,Virtual reality system,Graphics monitorStereoscopic glassesHead-tracking device,
