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Apparatus for measuring a small gap using a Savart plate
Apparatus for measuring a small gap using a Savart plate
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机译:使用Savart板测量小间隙的设备
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摘要
An apparatus that can measure a space between a first surface and a second surface such as the air bearing between a slider and a disk. The apparatus may include a light source that can reflect a light beam from the slider and the disk. By way of example, the light beam can be reflected off of an Al2O3 cap of a slider. A birefringent element such as a Savart plate may split the reflected light beam into an ordinary beam and an extraordinary beam. The ordinary and extraordinary beams may combine to form an interference pattern that is detected by a photodetector. A controller receives data from the photodetector. The apparatus may have a mechanism which can vary a phase between the ordinary and extraordinary beams so that the controller can calculate a phase value phi. The controller then computes the space from the phase value phi. The variation in phase between the beams may be created by tilting the birefringent element, or moving the reflected light beam directed into the birefringent element. The apparatus can determine the space without performing a retract calibration routine that moves the slider as is required in the prior art.
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机译:一种可以测量第一表面和第二表面之间的空间的设备,例如滑块和磁盘之间的空气轴承。该设备可以包括可以反射来自滑块和盘的光束的光源。举例来说,光束可以从滑块的Al 2 O 3盖反射出来。诸如Savart板的双折射元件可以将反射光束分成普通光束和非常规光束。普通光束和异常光束可以组合以形成由光检测器检测到的干涉图案。控制器从光电探测器接收数据。该设备可以具有可以改变寻常光束和异常光束之间的相位的机构,使得控制器可以计算相位值phi。然后,控制器根据相位值phi计算空间。光束之间的相位变化可以通过倾斜双折射元件或移动被引导到双折射元件中的反射光束来产生。该设备可以确定空间而无需执行如现有技术中所要求的移动滑块的缩回校准程序。
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