• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.17-22
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• 2011

LEDs(Light Emitting Diodes) are becoming widely used and increasingly in demand. Quality inspection of the LEDs has become more important. Two-dimensional inspection systems are limited in inspection capability, so threedimensional(3-D) inspection systems are needed. In this paper, a cost-effective and simple 3-D measurement system of LED packages using phase measuring profilometry(PMP) is proposed. The proposed system uses a pico projector to project sinusoidal fringe patterns and to shift phases instead of piezocrystal. It was evaluated using extremely accurate gauge blocks, yielding excellent repeatability of about 12 um(3-sigma). 3-D measurements of various LED packages were performed to demonstrate the applicability and efficiency of the proposed system.

• Korean Journal of Optics and Photonics
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• v.5 no.2
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• pp.191-197
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• 1994

We investigated the properties of various methods of 3 dimensional profilometry to choose the phase shifting technique for the reconstruction of the shape of a given specimen. The pattern was generated by a Twyman-Green interferometer and a PZT was used to shift the fringes on the target surface. The shape was calculated with Hariharan algorithm within the uncertainty of a scaling factor. The optical noise inherent in the laser source was observed to influence the final outcome to a great extent and the need for an exact calibration was noted. noted.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.6
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• pp.800-808
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• 1999

To compare several porcelains made by various manufacturers in shrinkage after firing and investigate the effect of condensation on shrinkage, specimens were prepared and the volume of each body was measured by the phase-shifting profilometry. Baseplate wax was cut by $2.5cm{\times}2cm$ and cast in nonprecious metal(Verabond, U.S.A.), then any surfaces of specimens were abrased and polished on the SiC abrasing papers, preparing 120 specimens. Specimens were divided into six groups according to the porcelain used, and the porcelain used in each group were as follows. Group I : Ceramco dentin porcelain Group B : Creation dentin porcelain Group III : Creation margin porcelain Group IV : Vintage margin porcelain Group V : Vita dentin porcelain Group VI : Vintage dentin porcelain Porcelain was built up on the metal plates using a small spoon and then solution matching to each porcelain was added. The six groups are subdivided into a and b. In subgroup a, only excessive solution was absorbed with tissue and in subgroup b, porcelain was condensed sufficiently. When build-up was completed, the shape was measured using the phase-shifting profilometry. After that, specimens were fired in the furnace programed for each porcelain and then their changed shape were measured again. Using the difference between the two above measurements, the ratio of shrinkage was calculated. Obtained results were as follows ; 1. Regardless of condensation, the volume of fired specimens were not different significantly between the two subgroups a and b in the same group. 2. The ratios of shrinkage were significantly higher in the groups porcelain built-up was condensed than in the groups not condensed 3. The ratios of shrinkage were in the range of 36.81-27.19% in the groups porcelain built up was condensed and 44.52-37.54% in the other groups not condensed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.335-341
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• 2005

The development of Shadow Moire in many kinds of methods for acquiring 3-dimensional information from an object is written in this paper. The fringe is appeared, when a grating mask makes its shadow on the object. The object is moved along x-axis more then 3 times to get phases from its fringe that contains data of the object's height. PMP{Phase Measuring Profilometry) is used for analyzing these images from a CCD camera. The calculated phase is remedied for expending the restricted results due to range of the $tan^{-1}$.