变焦距

To meet the needs of detection of space faint objects for a telescope with large aperture and short focal,a binding drawtube telescope scheme to detect space object is presented to overcome the shortcomings that focal length grows and field of view shrinks with the increasing of aperture size in traditional telescope for space detection.The software methods are used to stack collected images to restrain background random noises and to improve image Signal to Noise Ratio and the detecting ability of the whole system.

为了满足空间暗弱目标探测对大口径、短焦距望远镜系统的要求，克服普通望远镜随着口径的增加焦距变长、视场变小的不足，提出了将多镜筒捆绑在一起对同一空域进行观测，通过软件的方式对采集的图像进行叠加来抑制背景随机噪声、提高图像的信噪比和系统的整体探测能力的设想。

This method is proved feasible from a design example,it also shows that designed system is simple and compact and easy to fucus for zoom lens with large aperture.

标 签 变焦距物镜光学系统大口径成像质量 zoom lens optical system large aperture imaging quality

According to range of the focal distance, dropping UV glue which is crystalline and unexpensive into lens cavity with UV rays, and then forms as soon as solidifies the convex lens. Combining UV curing glue convex lens and variable focus lens, the focal distance range achieves the 8.3~24.5 mm low focal distance effect.

於此之后根据变焦效果的需要，利用UV胶透光性佳、成本低，将UV胶滴定於透镜腔体中，形成一凸透镜，藉由变焦透镜与UV胶透镜结合，焦距变化达到8.3~24.5mm范围的低焦距效果。

For testing zoom lens stray light, it is necessary to understand the role of every test component and their impact on the measurement results.

在对变焦距光学镜头进行杂散光系数测试的过程中，需要了解各测试环节的作用及对测量结果的影响。

A catadioptric step zoom lens for remote supervision TV is designed.

设计了一个用于远距离监视电视的折反射式步进变焦距透镜。

To improve the performance of zoom systems and achieve a good imaging quality in WFOV, and to simplify the mechanical structure for the convenience of design, process and adjustment, a design concept that combines the conventional spheric optics with the aspheric optics was introduced in the design of zoom lens.

为提高变焦距系统的工作性能，使其在大视场时仍具有良好的像质，且系统结构简单，易于机械设计、加工及装调，在设计中引入了传统球面光学设计与非球面相结合的设计思想。

Using two perfect plasma models(concentric sphere and variable focus ellipsoid), which have different shape and different gray distribution, the different cross-section tomograph figure and the gray density diagram are presented . The offset distance formula , which describes the laser beam penetrates through the laser welding plasma, is presented.

对两种理想的等离子体模型(三同心球体和变焦距椭球体)进行了分析，建立了不同剖面的密度分布层析图，给出了激光束穿越球形等离子体时由于折射引起的对光轴的偏移距离的公式。

New from Vicon Industries, Inc., of Hauppauge, New York, are six infrared varifocal lenses that can be used with true day/night cameras to provide sharp, focused images in daylight and at night, particularly in the presence of IR light.

源自美国纽约州Vicon实业公司的新型产品，六款红外变焦距镜头，各类日夜交替式摄像机，可以应用到在白昼、夜晚、尤其是红外光照射的环境下生成清晰的图像。

A varifocal f-theta lens was designed for Nd:YAG laser making scan focusing system, so that it apply to differ making area but change a lens necessarily. the system consists of four lens ,made by glass BK7, SF18 and SF11. The total length of the system is 122.96mm, working at 1064m.

为Nd：YAG激光打标机设计了变焦距f-theta镜扫描系统，以使它适用于不同的打标面积而不必更换镜头，系统由四片透镜组成，材料分别为BK7，SF18和SF11，系统总长度为122.96mm，工作波长1064nm。

The unit includes a removable infrared cut filter, digital signal processing circuitry with a 1/3-inch IT 410,000 pixel CCD, and backlight compensation. A 4x digital zoom complements the 2.5- to 6.0-millimeter varifocal, auto iris lens to ensure detailed close-ups.

摄像机还包括红外可拆卸截止滤光片，数字信号处理电路，1/3英尺IT的41万像素CCD以及背光补偿。4倍数字变焦补偿2.5到6.0毫米的变焦距，自动虹膜镜头确保详细的特写镜头。

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。