• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.205-215
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• 2011

Films are sensitive to ultraviolet rays and in contrast, digital camera sensors are extremely sensitive to infrared rays due to the differences in spectral characteristics. As a result, all digital cameras that use CCD or CMOS are equipped with IR Cut-Off Filter on the overall sensor. Complete block out of infrared rays is ideal, but the actual experiment results showed that infrared rays were not being blocked out completely. Infrared permeability was also different for each camera. Therefore, this study aims to analyze the effect of the minute quantities of infrared rays, which get transmitted due to mechanical properties of IR Cut-Off Filters that are installed on digital cameras, on digital picture images. The results obtained by carrying out a comparative analysis of a UV Filter (infrared transmitting state) and a UV-IR Filter (infrared blocked out state) are as follows. It was confirmed that the minute quantities of infrared rays do affect dynamic range and resolution to some extent, despite the little or no difference in noise and color reproduction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.373-374
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• 2007

• Journal of the Korean Society for Precision Engineering
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• v.24 no.11
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• pp.76-83
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• 2007

The dark-field laser scattering system has been developed to inspect surface defects in infrared cut-off filters and then laser scattering characteristics against the defects are investigated. The qualitative analysis for the reliable and accurate detection performance is described through the correlation between incident angles of a laser and viewing ones of a camera. In this paper, reliable and important information with laser scattering is given for the surface defect inspection of IR filters. Its performance has been verified through various experiments.

• Korean Journal of Optics and Photonics
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• v.35 no.1
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• pp.24-29
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• 2024

We propose a hyperbolic metastructure based on a nanopatterned metal (Ag)-dielectric (PDMS) multilayer and report on its performance in an infrared (IR) cut-off filter for imaging devices. By optimizing the size of the square-shaped Ag nanopattern and the thickness of PDMS surrounding the Ag nanopattern, the proposed IR cut-off filter blocks 99% of light in the 0.70-1.01 ㎛ wavelength band while maintaining a high transmittance of over 94% in the visible region. Here, the cut-off wavelength band starts at a region above the epsilon-near-zero wavelength of the hyperbolic metastructure and ends at the point where plasmonic absorption appears strongly. It is observed that transmittance in the wavelength region longer than the IR cut-off band increases again due to plasmonic coupling among horizontally adjacent Ag nanopatterns. This metastructure can improve the performance of IR-blocking filters as well as allow it to be manufactured ultra-thin, which is applicable to various planar optical elements and integrated optical components.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.58-64
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• 2009

In this paper, an inspection mechanism based on laser scattering has been developed for the surface evaluation of infrared cut-off filters, and optimum conditions of laser scattering are determined using the design of experiment. First of all, attributes and influence factors of laser scattering are investigated and then a laser scattering inspection mechanism is newly designed based on analyses of laser scattering parameters. Also, Taguchi method, one of experimental designs, is used for the optimum condition selection of laser scattering parameters and the optimum condition is determined in order to maximize the detection capability of surface defects. Experiments show that the proposed method is useful in a consistent and effective defect detection and can be applied to surface evaluation processes in manufacturing.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.1
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• pp.193-199
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• 1995

A novel imaging method in which time-division spinning reticle samples different pixel location of input image in different time is presented. The lens collects the beam passing throughthe reticle to a photodetector. Image reconstruction is accomplished by sampling the detector output corresponding to the spinning speed of reticle. Since the time-division reticle system removed the necessity of bandpass filter bank which has sharp cut-off characteristic, high resolution image is obtained without increasing the number of filter. To confirm the validity of this method, a computer simulation and an optical experiment using visual light are presented.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.207-212
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• 2023

Near-infrared (NIR) absorbing dyes have been applied to various applications such as optical filters, biotechnology, energy storage and conversion, coating additive, and traditionally information-storage materials. Because image sensors used in cellphones and digital cameras have sensitivity in the NIR region, the NIR cut-off filter is essential to achieving more clear images. As energy storage and conversion have been important, diverse NIR absorbing materials have been developed to extend the absorption region to the NIR region, and NIR absorbing materials-based research has proceeded to improve device performances. Adding NIR-absorbing dye with a photo-thermal effect to a self-healable coating system has been attractive for future mobility technology, and more effective self-healing properties have been reported. In this report, the chemical structures of representative NIR-absorbing dyes and state of the art research based on NIR-absorbing dyes are introduced.

• Journal of the Optical Society of Korea
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• v.19 no.1
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• pp.102-111
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• 2015

This paper proposes an algorithm for recovering the colors of objects from multiple near-infrared (near-IR) images. The International Commission on Illumination (CIE) color coordinates of objects are recovered from a series of gray images captured under multiple spectral near-IR illuminations using polynomial regression. The feasibility of the proposed algorithm is tested experimentally by using 24 color patches of the Color Rendition Chart. The experimental apparatus is composed of a monochrome digital camera without an IR cut-off filter and a custom-designed LED illuminator emitting multiple spectral near-IR illuminations, with peak wavelengths near the red edge of the visible band, namely at 700, 740, 780, and 860 nm. The average color difference between the original and the recovered colors for all 24 patches was found to be 11.1. However, if some particular patches with high value are disregarded, the average color difference is reduced to 4.2, and this value is within the acceptability tolerance for complex image on the display.

• Korean Journal of Optics and Photonics
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• v.13 no.4
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• pp.363-369
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• 2002

We have designed conductive transparent filters using a low-emissivity coating such as [dielectric|Ag|dielectric] for display applications. The design is the repetition of [$TiO_{2}$|Ti|Ag |$TiO_{2}$] to increase the transmittance in the visible and decrease the transmittance in the near IR. The conductive transparent filters are deposited by a radio frequency(RF) magnetron sputtering system. The optical, structural and electrical properties of the filters were investigated and the optical spectra are compared with simulated spectra. The thickness of the deposited Ag films is above 13 ㎚ to increase the conductivity and that of $TiO_{2}$ films is 24 ㎚ to increase the transmittance in the visible range. Ti blockers are employed to prevent the Ag films from being oxidized by an oxygen gas during the reactive sputtering process. Also, it is shown that the thicker Ti film is necessary as the period increases. Finally, a filter with repetition of the basic structure three times shows the better cut-off near infrared(NIR) and the sheet resistance as low as 2Ω/□ which is enough to shield an unnecessary electromagnetic waves for a display panel.