Based on Lau effect in double grating, the focal distance of lens is measured.
根据计量光栅的特点，可以利用双光栅效应测量透镜焦距。
In measuring the focal distance of lens, the experimental accuracy is often affected by the poor quality in the formation of images.
在测量透镜焦距时，往往由于成像质量差而影响实验的精度。
If you know the FOV, sensor size, and working distance, you can compute the focal length of the lens you need using the following formula.
如果你知道视野FOV，感应器大小，和工作距离，你能用以下之方程序去计算你所需之镜头的焦距。
A lens is primarily defined by its focal length. Figure 4 illustrates the relationship between the focal length of the lens, field of view, sensor size, and working distance.
一个镜头的基础定义是其焦距，图4图示出镜头焦距，视野，感应器大小，和工作距离间之关系。
Focal length: The distance between the centre of a lens and its principal focus.
焦距：镜头中心与其主焦点的距离。
It is shown that by changing the focal length of focal lens and the distance between the axicon and the lens, the center of dark of the bottle beams can be altered effectively.
这些结果表明，改变聚焦透镜的焦距和聚焦透镜到轴棱锥间的距离以及光阑半径，可有效地改变局域空心光束的暗中空区域。
Moreover, applying the matrix method in the close axis optics leads directly to the expression of the focal distance of magnetic lens if the matrix is transmitted by the lens.
此外，应用类似于近轴光学中的矩阵方法，山磁透镜传输矩阵，直接导出了该磁透镜的焦距的表达式。
Abstract: the rules of ganssian light beams extended by lens are disscussed firstey and the relation between the optimum waist extended and focal distance of the lens are found out.
文摘：首次讨论了用透镜来扩展高斯光束的一般规律，找出了最佳扩展束腰与透镜焦距的关系。
This text is to compare Frensnel s zones plate with ordinary lens, on the axle point of light intension and focal distance as well as their difference in use.
当光通过菲涅耳半波带与普通透镜时，可发现在轴上点的光强、焦距以及用途上的不同。
The influences of pump energy, focal length and distance between fiber and lens on SBS reflectivity and waveform in multimode fiber are investigated theoretically and experimentally.
从理论和实验上研究了不同焦距下泵浦能量以及透镜与光纤间距对多模光纤中的SBS能量反射率和脉冲波形的影响。
An experimental investigation of the combination of a long focal distance Bragg-Fresnel lens with a bimorph mirror is described.
描述了对长焦距布拉格-菲涅耳透镜与可变曲率半径反射镜组合所做的实验研究。
Used to observe the details of a simple visual objects, optical devices, is the focal length than the distance between eyes, as much out of the convergence lens.
用来观察物体细节的简单目视光学器件，是焦距比眼的明视距离小得多的会聚透镜。
From the focal distance formula of thin lens, the convergence and divergence nature of each kind of thin lens are discussed in different media.
从薄透镜的焦距公式出发，讨论了各种透镜在不同介质中的会聚与发散性质。
Conjugate method is an accurate, simple and convenient method to measure the focal distance of thin convex lens.
共轭法是一种较为准确和简便的测量薄透镜焦距的方法。
The position of the image and the amplitude variation in the optical field are associated with the focus and the distance from the object to the front focal plane of the lens system.
象的空间位置和光场振幅的变化与透镜系统的焦距以及物体距焦平面的位置有关。
Measuring the focal lengths of thin lens by means of object distance and image distance is a commonly utilized method in geometric optics.
利用物距、像距法测量薄透镜的焦度是几何光学中最常用的方法。
One major problem the researchers had to overcome was the fact that the human eye, with its minimum focal distance of several centimetres, cannot resolve objects on a contact lens.
研究人员必须解决的一个重要的问题是，人眼的最小焦距是几厘米，无法分辨出隐形眼镜上显示的物体。
One major problem the researchers had to overcome was the fact that the human eye, with its minimum focal distance of several centimetres, cannot resolve objects on a contact lens.
研究人员必须解决的一个重要的问题是，人眼的最小焦距是几厘米，无法分辨出隐形眼镜上显示的物体。
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