The aim must be to achieve the requirements of lens focal length.
其目的是必须达到凸透镜焦距的要求。
The bifocus lens could produce images at the two independent focal length respectively and recovery the object`s depth information according to the two bifocal images, which is the principle of depth estimating using bifocal lens.
成像物镜具有两个独立的焦距，通过对空间物体成像并进行分析可获取其深度信息，此即双焦测距的原理。
Focal length of the lens used, the exposure mode, flash settings and of course the time and date.
KEY：随着每一次按下快门，数码相机记录下了包括镜头所用的焦距，曝光模式，闪光效果在内的所有数据，当然也包括拍照时间和日期。
The ratio of the focal length of a lens or lens system to the effective diameter of its aperture.
光学仪器的目镜上的细线、圆点、十字型细线或金属丝组成的系统。
The paper design start point with a four-group the paraxial lens set with two groups lens of movements, among the first order and three order aberration is ignored. The imprimis acquisition optical zoom focal length start the structure.
本文的初始的设计以四群组成二群移动的理想透镜组，其中不考虑一阶及三阶象差，首先取得光学变焦的初始结构。
The ratio of the focal length to the diameter of a lens system.
颅骨最大长度和最大宽度的比率。
The focal length of a given lens is different for different colors.
一个特定的透镜的焦距因颜色的不同而不同。
If the objective lens is closer to the compact disk than the focal length of the object lens, then the cylindrical lens creates an elliptical image on the photodetector array.
如果物镜与光盘之间的距离短于物镜的焦距，柱面透镜就会使在光电探测器阵列上的成像变成椭圆影像。
Auto sensitivity control function automatically sets the optimum sensitivity between ISO 100 and ISO 3200, based on the subject`s brightness level and the lens` focal length.
自动灵敏度控制功能自动设定最佳的灵敏度与使用ISO 100和ISO 3200的基础上，主体的亮度水平和镜头焦距。
A device for modifying the enlargement factor by modifying the focal length and a device for adapting the parallax between the lens systems of the visual aid to the focal length that is adjusted according to the distance of the telescopic spectacles from the object are also allocated to the lens systems.
透镜系统还配置一个用于通过改变透镜系统的焦距来改变放大倍数的装置和一个使助视器的透镜系统之间的视差适配于根据望远镜与对象之间的距离而被调整的焦距的装置。
Infinitive Optical systam, Tube Lens Focal Length 200mm
无限远光学系统，管镜焦距200mm
As substitute for fluorite lens, a double-layer DOE is used in a long focal-length apochromatic objective lens.
0引言表面微结构衍射光学元件在现代光学系统中的应用越来越广泛[1-2]。
As substitute for fluorite lens, a double-layer DOE is used in a long focal-length apochromatic objective lens. The modulation transfer function of this hybrid optical system is suggested for evaluating diffraction efficiency of the multilayer DOE. The results show the diffraction efficiency has a wide and symmetrical distribution in the whole waveband.
利用双层衍射光学元件替代萤石透镜校正混合光学系统的二级光谱，设计并制作了一套长焦距物镜，并利用系统调制传递函数评价了多层衍射光学元件衍射效率，测试结果表明衍射效率在整个设计波段内以较高的数值平均分布。
Taking the laser diode line generator as the light source, the parallel laser screen unit was formed by using aplanatic cylindrical Fresnel lens with long focal length. By splicing seamlessly with multiple parallel laser-screen units, the large area laser screen can he constructed.
以半导体激光线发生器为光源，用长焦距消球差的柱面菲涅耳透镜形成平行激光幕单元，通过多个平行激光幕单元的无缝拼接可形成大面积靶面。
AW: In general terms in the design of a lens the size of the lens can be minimized when the focal length and back focus distance are roughly equal.
伍尔兹：从总体上看在设计镜头大小的镜头时，可以减少焦距和背部重点距离大致相等。
In the lens assembly, plastic lenses were chosen instead of glass/plastic hybrid or all glass lenses for the cost and production consideration. The back focal length of the digital camera was increased by 0.8116 mm with the lens assembly. Therefore, it can guarantee a better performance for the telecentric beam path. The profiles of the three lenses were designed as aspheric surfaces so as to correct the aberration and ensure the excellent optical performance.
该数码相机镜头结构的特点是：模块仅包括3块透镜；选择塑料镜头代替玻璃/塑料混合镜头或者全玻璃镜头，降低了系统的生产成本；系统的后焦距增大到0.8116mm，能够确保良好的远心光路性能；透镜表面完全采用非球面设计，较好地校正了球差等各种像差，使透镜具有良好的光学成像性能。
The spot patterns of the backward scattering light does not change with the pumping light spot, but its size is enlarged with the increase of the focal length of the lens. There exists maximum for the pulse width and the energy of the scattering light, which rise and then fall, with the rise of the gas pressure of the medium. The energy reflectivity is 1%～3%, and there exists pulse width compression effect for the backward scattering light, related with gas pressure of the medium.
任意改变抽运光的光斑形状均不影响后向散射光的光斑形状，随透镜焦距的增加散射光光斑口径增大；散射光的脉冲宽度和能量大小随介质气压的升高先升后降，存在极值现象；能量反射率为1％～3%；后向散射光脉宽具有脉宽压缩特性，且与介质气压有关；用聚焦透镜和介质池取代激光器的后镜，可自动成腔输出激光。
Beijing Fangwei Electronics Co., Ltd., the main research and development products: anti-theft security system alarm system host infrared detector monitoring system hard drive video camera audio and video wireless transmitter video compression card monitoring equipment, in particular to promote the focal length of 200 mm lens color infrared waterproof perturbation As the network of video cameras network server wireless video transmitters pc hard drive digital video recorders embedded in digital audio and video compression DVR card also known as compression card infrared detectors monitor the infrared detectors on the radio for highway camera: The road monitoring Minimum illumination light curb high-definition color video camera license plate identification camera blackout probe.
北京方伟电子有限公司，主要研发产品有：安防系统防盗系统报警主机红外探测器监控系统硬盘录象摄象机无线音视频发射器视频压缩卡监控设备特别推介焦距200mm镜头彩色红外线防水摄象机网络摄象机网络视频服务器无线视频发射器 pc式数字硬盘录象机嵌入数字硬盘录像机音视频压缩卡又称监控压缩卡红外线探测器红外线对射探测器高速公路专用摄象机：道路监控强光抑制高解析低照度车牌识辨摄像机彩色摄象机停电探测器。
Dynamic focal length of thermal lens and light deviation angle is computed with Light transfer matrix, q parameter and ABCD law.
该方法通过高速相机以5Khz的拍摄频率获取TEM00模He-Ne激光的光斑尺寸和位移变化，运用光学矩阵、q参数和ABCD法则，计算得到了动态热透镜焦距和光走离角。
The compact scheme of optical system is proposed, which solves the big volume problem resulting from the long focal length. The folding scheme of the optical system is proposed and the optical parameters of telephoto lens are designed.
c。进行了光学系统紧密结构设计，提出了折叠式光学系统设计方案，并设计了摄远型傅立叶物镜，解决了由于长焦距镜头所导致的仪器体积庞大问题。