Basic research of a laser scanner having a wide field of view with the almost same resolution as a scanning electron microscope

我们研制的激光扫描器由半导体激光器、准直透镜、旋转平面镜、铁透镜和光电二极管组成。它采用了扫描共聚焦显微镜系统。fe透镜由几个光学透镜组成。他们被固定在一个铝外壳与收缩fitter，一个新的机器元件，我们已经开发。通过使用具有收缩拟合器的fe透镜，我们可以在0摄氏度至+60摄氏度的任何温度下，在10毫米的宽扫描宽度上将激光光斑的直径保持在几乎3_1米。观察测试图以估计我们的激光扫描仪的放大率。然后可以发现，通过将激光扫描仪转换为光学显微镜的物镜透镜的放大率，激光扫描仪的放大率几乎为x20。那是激光扫描仪捕捉到的图像的垂直抖动。这是因为支撑旋转平面镜的球轴承引起的振动。因此，自动空气轴承被用来代替球轴承。在平面镜粘附到空气轴承之后，通过调整镜保持器的重量来动态平衡组件。因此，扫描仪捕获的图像的垂直抖动能够被降低到某个固定值。此外，还对激光扫描仪的软件进行了改进，使激光扫描仪能够正确检测激光扫描的起始点。本研究所用的A/D转换板是100 MHz的高速A/D转换板，它将反射光强度转换成数字化数据。因此，我们可以观察到的对象在0.5 - 1米的间隔超过10毫米的宽扫描宽度。我们做的激光扫描仪安装在防振装置，使振动的外部影响最小。

A laser scanner we have developed consists of a semiconductor laser, collimator lens, a rotating flat plane mirror, a fe lens and a photodiode. It has adopted a scanning con focal microscope system. The fe lens consists of several optical lenses. They were fixed in an aluminum housing with a shrink fitter, a new machine element we have already developed. By using the fe lens with the shrink fitter we made it possible to keep the diameter of the laser spot constant at almost 3_1 m over a wide scanning width of 10mm at any temperature from 0 degrees C to +60 degrees C. A test chart was observed to estimate the magnification of our laser scanner. Then it could be found that the magnification of the laser scanner was almost x20 by conversion of it to that of an objective lens of an optical microscope.We have almost succeeded in trail production of the laser scanner except for one thing. That was a vertical jitter of the image captured by the laser scanner. This was because of the vibration caused by the ball bearing which supported the rotating flat plane mirror. Thus a self-acting air bearing was used instead of the ball bearing. After the flat plane mirror was adhered to the air bearing, the assembly was dynamically balanced by adjusting the weight of the mirror holder. As a result, the vertical jitter of the image captured by the scanner was able to be made below into a certain fixed value. In addition the software of the laser scanner was also improved to detect correctly the starting point of the laser scanning.The A/D converter board used in this research, which changes the catoptric light intensity into digitized data, was the high-speed type of 100MHz operation. Thus we could observe the object at intervals of 0.5 1 m over the wide scanning width of 10 mm. The laser scanner we made was installed on the anti-vibration device to make external influence of vibration minimum.