焦距

Since the focal length is a purely paraxial size, numerous sources of error exist during the focal length

因为焦距是一个近轴尺寸，在实际物镜测量过程中存在许多误差源。

The infrared coupling optical system is a middleinfrared system with a long focal length, larger field and telecentric beam path in image space, which is required to match with the parameters of two homing optical systems.

该红外光学系统是一个要求与2个导引光学系统的光学技术参数相匹配的长焦距、大视场和具有像方远心光路的中红外光学系统。

We do not pursue the perspicuity in visual focus, whereas we ponder over the moments of the meeting and the merging of thoughts.

我们并不刻意追求视觉焦距的明晰，而是去琢磨心思相遇相浑的瞬间。

Furthermore, the author analyzed the influence of different hardwares on image quality, grabbing speed and detecting speed in detail, and proposed some principles about selection of camera lens and plane mirror.

并详细探讨了硬件的选择对图像质量、采集速度、检测速度的影响，给出了镜头焦距和平面镜的确定原则。

In order to study the output characteristics of diode-end-pumped Nd:YAP laser operating at 1341.4nm,the thermal focal lengths of end-pumped Nd:YAP laser were calculated and measured,and the output results of lasers with plane-plane and plano-concave resonators were compared respectively.

为了研究Nd：YAP晶体在LD端面抽运中的1341.4nm激光输出特性，采用理论计算和实验测量了实验系统的热焦距，对比了平平腔和平凹腔激光输出结果。

The latest experimental results of the focusing perfermance of the compound high-energy X-ray lens is designed with PMMA with the parameters of 40 plano-concave elementary lenses positioned in line with axial symmetry, 200 μm radius of the concave surface, 0.15 nm working wavelength, 0.5 mm geometrical aperture and 8 mm length of the compound lens and 1.3 m focus length, are briefly introduced.

报道了这种新型X射线光学元件聚焦性能的最新实验结果。设计的高能X射线组合透镜为聚甲基丙烯酸甲酯材料，包括40个相同的、顺序排布的平凹折射单元，折射单元的球面半径为200 μm，组合透镜的几何口径约为500 μm，长度约为8 mm，焦距约为1.3 m。简要描述了PMMA材料X射线组合透镜的制作技术和制作过程。并给出了X射线组合透镜聚焦性能测试实验系统和实验条件。

Conventional stereoscopic displays can cause viewers to experience eye fatigue and discomfort,as well as compromise image quality, because these displays require the viewers to unnaturally keep the eye focal length fixed at one distance while dynamically changing the convergence point of the left and right eyes to view objects at different distances.

传统的立体显示器需要观众人为地将眼睛的焦距固定在某一个距离，不断改变左、右眼收敛点来观察不同距离的物体，因此会造成眼疲劳和不适感，也降低了图像质量。

When Zeiss Jena in 1985 introduced a new high-end line of Porro Prism binoculars, which originally included the 8x50 Octarem and the 12x50 Dodecarem, they did something very smart: They returned back to the classical design with a long body shape, allowing for longer focal lengths and therefore relaxing the technical requirements inherent in the Nobilem Super without the need to sacrifice optical performance.

1985年Zeiss Jena生产了一款新的高端保罗望远镜，最初包括8x50 Octarem和12x50 Dodecarem，它们在下面事上做的很聪明：返回到了长身躯的传统设计，允许更长的焦距，于是放宽了Nobilem Super固有的技术要求，也不需要牺牲光学性能。

The paper studies the optical properties of a magnet with tilted magnetic poles, calculates the focusing distance and principal plane of the 90° magnet and discusses the magnetic parameter satistying the respectively conditions of double focusing, stigmatic double focusing, maximum dispersion, minimum dispersion and zero dispersion.

本文推导了具有倾斜磁极磁铁的光学特性，计算了90°磁铁的焦距和主平面以及讨论了满足双聚焦、消象散双聚焦、最小色散、最大分辨率、零色散条件的磁铁参数。

A calibration scheme of calibrating some parameters, such as the principal point, focal length, distortion, of star sensor is brought forward.

论文提出了一种对星敏感器的主点、焦距、一阶径向畸变等参数进行标定的方法。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。