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Park, Ji-Hee;Lee, Jung-Ho;Jeong, Jin-Ha;Nahm, Kie-Bong;Ko, Jae-Hyeon;Kim, Joong-Hyun
- Korean Journal of Optics and Photonics
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- v.18 no.6
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- pp.432-440
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- 2007
Optical simulation methods such as a ray tracing technique have been widely used to predict the optical performances of collimating films for LCD backlight applications. It is necessary to optimize simulation conditions which have substantial effect on the simulation result in order to predict accurate performances of collimating films. We have set up a very simple backlight model consisting of a reflection film, a virtual flat light-source, and a prism film, which is a representative collimating film for backlight, in order to analyze the simulation conditions which are strongly correlated with the on-axis luminance gain and the viewing-angle characteristics of prism films. It was found that the dependence of the relative change in the on-axis luminance on the structure and material properties of collimating films can be derived from the above-mentioned simple BLU model and from simulation using it. However, the exact reflection property of the reflection film and the distribution of the incident light onto the optical film were found to be very important for revealing exact viewing-angle characteristics of collimating films.
https://doi.org/10.3807/HKH.2007.18.6.432 인용 PDF KSCI

Lee, Jae-Ran;Kim, Sok-Won;Lee, Yong-San
- Korean Journal of Optics and Photonics
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- v.19 no.3
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- pp.182-186
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- 2008
The prism spectrometer is a standard device for the measurement of refractive index; it is used in undergraduate laboratories. Typically, however, lots of attention is required in the alignment, and the accuracy of the obtained refractive index is not so high in spite of the durability of the device. The maximum and minimum deviation method, which compensates the disadvantages of the prism spectrometer, can be composed cost effectively using a length marking tape and a rotating platform. It can measure the refractive indices accurately by utilizing a wide screen. In this study, the equal sided hollow prism whose length is 26 mm was fabricated and measured the refractive indices of seven kind of liquids (pure water, $C_3H_5(OH)_2$, $CCl_4$, $C_6H_4NH_2$, $CS_2$, $C_6H_4(CH_3)_2)$ by using the prism spectrometer and maximum and minimum deviated laser beam method at the wavelengths of He-Ne laser (${\lambda}$= 632.8 nm) and YVO4 laser (${\lambda}$= 532 nm). The result shows that the data obtained by the latter method are more accurate and precise than those obtained by the former device.
https://doi.org/10.3807/HKH.2008.19.3.182 인용 PDF KSCI

In-Ung Song;Woo-Sung Kwon;Hagyong Khim;Yun-Woo Lee;Jong Ung Lee;Ho-Soon Yang
- Korean Journal of Optics and Photonics
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- v.34 no.3
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- pp.117-123
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- 2023
The size of an optical surface can significantly affect the performance of an optical system, and high spatial frequency errors have a greater impact. Therefore, it is crucial to measure the surface figure error with high frequency. To address this, a new method called rotational prism stitching interferometer (RPSI) is proposed in this study. The RPSI is a type of stitching interferometer that enhances spatial resolution, but it differs from conventional stitching interferometers in that it does not require the movement of either the mirror tested or the interferometer itself to obtain sub-aperture interferograms. Instead, the RPSI uses a beam expander and a rotating Dove prism to select particular sub-apertures from the entire aperture. These sub-apertures are then stitched together to obtain a full-aperture result proportional to the square of the beam expander's magnification. The RPSI's effectiveness was demonstrated by measuring a 40 mm diameter spherical mirror using a three-magnification beam expander and comparing the results with those obtained from a commercial interferometer. The RPSI achieved surface testing results with nine times higher sampling density than the interferometer alone, with a small difference of approximately 1 nm RMS.
https://doi.org/10.3807/KJOP.2023.34.3.117 인용 PDF