In the optical non-contact measure fields, the white light interferometry technique is well-known. The measure resolutions of vertical and horizontal direction are determined by motion mechanism and grabbed images, respectively. Therefore, to permit measurement resolution of white light interferometry in 3D profile is very important. In this paper, a white light interferometric measurement technique that combines vertical scanning and phase shifting is proposed. High resolution of the vertical scanning technique can grab the images of short pitch displacement. The relationship between interference fringe and changed frequency of these images are solved by the FFT. Then, the interference fringe's center is computed by band-pass filter and maximum power position. The phase shifting is based on five-frame algorithm to acquire fringe order through vertical scanning. In the experiment result, first was used the grating that had calibrated by commercial instrument Talysurf CCI 6000 to calibrate the experiment implement longitudinal resolution, second was measured the roughness calibration gauge of Model SS-NS94/ No. N20674 /Ra 3.0μm. The results show that the resolution is arrived 1nm, it was quite obvious improving the traditional mechanic.
Rapid mixing is essential in biochemical analysis, drug delivery, biomedical inspection, as well as RNA and DNA synthesis and testing. A suitable evaluation method is required for mixing effect comparison in the stage of research and development of mixers. Until now, no satisfactory method was developed to quantitatively evaluate the mixing performance of micromixers. We describe an inspection algorithm that uses image gray level to evaluate the mixing effect in micromixers. Computer simulation results show that the mixed range and the mixing concentration can be recognized. Experiments are implemented in a self-designed two-channel micromixer, in which the diameter of the mixing chamber is 1 mm and height is 200 µm. Experimental results show that the proposed algorithm can clearly display the full-field mixing state in the mixer, so that it is helpful to evaluate the performance of a micromixer. In addition, a mixing efficiency over 90% is obtained within 0.35 s at a flux of 7.81 µl/s in the self-designed mixer. Since the purpose of rapid and uniform mixing is obviously achieved, this mixer can be applied to the field of biomedical diagnosis.
Rapid mixing is essential in many of the micro-fluidic systems targeted for use in the testing of biochip analysis, drug delivery, and analysis or synthesis of blood, among others. A design of a passive micro-mixer is presented in this paper. The mixing is based on the vortex phenomenon of fluid stirring and diffusion. The size of the mixer chip is 10mm×10mm, with a width of the channel of 200μm and a depth of 50μm. This mixer allows fast mixing of small amounts of liquids. A mathematical model that uses gray level contrast to evaluate the mixing efficiency is also proposed. The measurement principle is based on the statistical concept via a quadratic weighting distribution. Experimental results show that the mixing efficiency is over 80% for mixing two liquids with the same polarization and roughly 90% for the mixing of two inks. Thus a new type of biochip can be easily implemented with this system for the application in biomedical diagnostic technology.