Journal of Science and Technology in Lighting最新文献

{"title":"Combination of Concave and Convex Paraboloids: Theoretical Model of New-type Daylighting System","authors":"Yusuke Tsuji, Hirotaka Suzuki","doi":"10.2150/jstl.ieij200000643","DOIUrl":"https://doi.org/10.2150/jstl.ieij200000643","url":null,"abstract":"We investigate the behaviour of a new-type daylighting system composed of concave and convex paraboloidal mirrors. This system realises converting parallel light into highly-dense parallel before passing through the focal point. It means that the system solves one of the significant problems in daylighting sys -tems: heat problems. In this paper, we set up the theoretical model of our new-type daylighting system, check the model using the two-dimensional ray-tracing code, confirm the relation between simulated data and simulation resolutions, introduce convenient contour maps and three type performance indexes and estimate the performance of our system.","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121066269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effect of Spectral Power Distribution of White Light-Emitting Diodes on Eye Fatigue","authors":"Jun-ichi Sugimoto, Y. Akashi, Yuki Hiraga, M. Inatani, Emi Kaga, Shota Shimonishi","doi":"10.2150/jstl.ieij210000647","DOIUrl":"https://doi.org/10.2150/jstl.ieij210000647","url":null,"abstract":"","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132210689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Relationship between Solid Angle, Eccentric Angle, and Luminance of Glare Source Under the BCD Condition to Understand the Effect of Visual Characteristics on Discomfort Glare","authors":"K. Takase, N. Hara","doi":"10.2150/JSTL.IEIJ190000637","DOIUrl":"https://doi.org/10.2150/JSTL.IEIJ190000637","url":null,"abstract":"Unified glare rating (UGR), which is a general discomfort-glare index, targets design objects such as artificial lighting. Light-source size, position of gaze, etc. are limited to the specific range assumed in the process of developing UGR. Because it is necessary to reflect human visual characteristics to universally predict the rating of discomfort glare according to visual science, it is necessary to understand the ef-fects of visual characteristics on discomfort glare. In this study, which was conducted to systematically investigate visual characteristics in the visual field of discomfort glare, the effects of the solid angle and eccentric angle of the light source on the borderline between comfort and discomfort (BCD) luminance of discomfort glare were experimentally investigated. The results of the experiment revealed that the effect of light-source solid angle on BCD luminance depends on the eccentric angle. The results confirm the necessity of understanding the visual characteristics in terms of the effects of size and position of the light source on discomfort glare.","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132545899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Realization of UV-emitting LEDs","authors":"T. Morishita","doi":"10.2150/JSTL.IEIJ20A000008","DOIUrl":"https://doi.org/10.2150/JSTL.IEIJ20A000008","url":null,"abstract":"As the novel-coronavirus pandemic continues to spread globally, the effectiveness of deep-ultraviolet rays in regard to inactivating the virus is drawing attention. Mercury lamps are widely used as a deepultraviolet light source; however, in recent years, deep-ultraviolet LEDs, which have the advantages of low environmental load and short start-up time, have been attracting attention. The virus is inactivated and sterilization is achieved by its DNA absorbing the deepultraviolet light, which destroys the double-helix structure of the DNA, which thereby loses its amplification function. Accordingly, as shown in Figure 1, the sterilization efficiency of deep-ultraviolet light is the highest in the wavelength region around 265 nm, at which deepultraviolet absorption rate of the DNA is high1). Conventional deep-UV LEDs are manufactured on sapphire substrates and SiC substrates2–4); however, when such substrates are used, the difference in lattice constants and the difference in coefficients of thermal expansion of the semiconductor materials are large. As a result, line defects with density of 108 cm-2 or more occur, and the resulting low luminous efficiency is a problem. Therefore, to reduce that line-defect density, methods such as epitaxial lateral overgrowth (ELO) have been innovated. The correlation between internal quantum efficiency and line-defect density has also been investigated, and it has been reported that a line defect acts as a non-emissive recombination center, so it is very important to reduce line-defect density5, 6). To address these issues, it is very effective to use aluminum nitride (AlN) as the substrate because its physical constants (namely, lattice constant and coefficient of thermal expansion) are similar to those of the semiconductor material. As for LEDs manufactured on an AlN substrate, line-defect density can be suppressed to 105 cm-2 or less. What’s more, taking advantage of the small difference in lattice constants makes it possible to create an LED with high output in the 265-nm wavelength band, in which sterilization efficiency is highest. Utilizing these technologies, we launched a “sterilization LED” commercially in 2017. Moreover, we have developed a “water-sterilization module” using a 265nm LED, and this module demonstrated sterilization performance for Escherichia (E.) coli at flow velocity of 2L/min of 99.9% or more. We commercialized a watersterilization module based on this LED in May 2018. In addition, with the growing interest in deepultraviolet LEDs against the backdrop of the novelcoronavirus pandemic, we are doubling our efforts to further improve the efficiency of LEDs. LED efficiency is expressed as the product of carrier-injection efficiency, internal quantum efficiency, and light-extraction efficiency. Given that fact, we improved (i) carrier-injection efficiency by improving the thin-film structure and (ii) light-extraction efficiency by reducing the absorption coefficient of the AlN substrate to","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124044738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"State-of-the-art Technology: Inactivation of Pathogens Using a 222-nm Ultraviolet Light Source with an Optical Filter","authors":"H. Ohashi, Toru Koi, T. Igarashi","doi":"10.2150/JSTL.IEIJ20A000006","DOIUrl":"https://doi.org/10.2150/JSTL.IEIJ20A000006","url":null,"abstract":"Introduction Ultraviolet (UV) radiation with wavelength of 254 nm has been widely used for sterilization and inactivating viruses. UV radiation with wavelength of 254 nm can effectively inactivate viruses and bacteria; however, irradiating the human body with such UV light can cause skin cancer and internal disorders. Use of UV irradiation at that wavelength in environments in which people are present has thus been avoided. Even so, UV radiation with wavelength of 222 nm has recently been attracting attention because it has a strong effect in terms of sterilization and inactivating viruses in a similar manner to conventional 254-nm-wavelength UV radiation. As for safety, it has been confirmed by multiple medical institutions and universities that 222nm UV is much safer than the conventional 254-nm UV radiation. If UV radiation were harmless to people, it could be used for sterilization and inactivating viruses in any public and commercial facilities in which people are socially active, such as hospitals, schools, and offices. It is therefore expected to balance the tradeoff between suppressing pandemics and maintaining social and economic activities.","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121477055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sterilization Technology Using an Ultraviolet-radiation Source","authors":"A. Tauchi","doi":"10.2150/JSTL.IEIJ20A000007","DOIUrl":"https://doi.org/10.2150/JSTL.IEIJ20A000007","url":null,"abstract":"1. About UV-radiation sterilization Ultraviolet (UV) radiation is classified according to its wavelength as UV-A (wavelength: 315–400 nm), UV-B (280–315 nm), and UV-C (100–280 nm). UV-C, which is the UV radiation contained in sunlight, is absorbed by the ozone layer. UV-A and UV-B, which reach the surface of the earth, cause sunburn, but their sterilization effect is low. UV-C (with short wavelength) imparts high energy per photon, and it can be efficiently absorbed by the DNA and RNA possessed by bacteria and viruses and thereby destroy the genetic information held by the DNA, suppress cell division and proliferation, and sterilize things (i.e., inactivate microorganisms). The maximum absorption of UV by DNA is around the wavelength of 260 nm. Accordingly, as for the light source for UV sterilization, two kinds of lamps are widely used: (i) low-pressure mercury lamps (which efficiently emit the 254-nm bright line of mercury) and (ii) mediumand high-pressure mercury lamps, which have lower luminous efficiency but higher radiation density that low-pressure mercury lamps and generate broad light emission around 260 nm. In recent years, LEDs in the deep-ultraviolet radiation region have also been developed, and they are expected to be a “mercury-free” light source in the future. In this article, the usefulness of such UV-radiation sterilization, including the features and practical examples of various UV-radiation light sources, is explained.","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125545530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Adrian/CIE Visibility Model: A Visibility Level Calculator & Future Research","authors":"Adrienne S. Kline, D. Kline, T. Kline","doi":"10.2150/jstl.ieij200000640","DOIUrl":"https://doi.org/10.2150/jstl.ieij200000640","url":null,"abstract":"Diminished visibility in dim light degrades performance and safety on real-world tasks that depend on the timely detection of visual targets. The goals of this paper are to: 1. review factors that affect nighttime visibility, with an emphasis on driving, 2. provide the reader with online access to an automated modified Adrian/CIE visibility level (VL) calculator (VLC), and 3. suggest future research for enhancing the objective measurement of visibility. Recognizing that luminance contrast is the primary sensory determinant of nighttime visibility, several contrast-detection models have been proposed to quantify visibility in dim lighting. Of these, the Adrian (1989) model accounts for comparatively more of the important variables and has been the most widely accepted. The mathematical steps for calculating target VL in the modified Adrian/CIE model are presented and the VLC user interface is explained in step-by-step order. The VLC provides an easy-to-use tool for calculating target VL. Several additional factors that affect VL that are not currently included in the model provide important research opportunities for enhancing the measurement of target visibility in nighttime conditions. The VLC is an open-access application intended to foster the measurement of VL in professional practice and to foster research to advance the utility of the Adrian/CIE model.","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129806659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance Evaluation and Optimization of Design of Light Focus in Otoscope during Otoscopic Examination by Headlight","authors":"M. Matsumoto","doi":"10.2150/jieij.190000584","DOIUrl":"https://doi.org/10.2150/jieij.190000584","url":null,"abstract":"We evaluated the performance of light focus in an existing otoscope with a headlight employing an LED source. The mechanism of the otoscope was shown, and a coordinate system was set in the otoscope to evaluate the light-focusing performance. Experimental equipment based on the set coordinate system was built using the existing otoscope and headlight. We demonstrated experimental methods for measuring illuminance at the narrow mouth in the otoscope using the built experimental equipment. In the experiments conducted using the experimental methods, the performance of light focus in the existing otoscope was evaluated by measuring the illuminance. The optimal new otoscope for focusing light was designed using a headlight employing the LED source. The otoscope was built using the results obtained by the designs. We evaluated the performance of light focus in the designed otoscope with the otoscopes we built. The experimental equipment was built with the constructed otoscope and the headlight. We demonstrated experimental methods for measuring illuminance at the narrow mouth in the otoscope using the built experimental equipment. In the experiments conducted using the experimental methods, the performance of light focus in the designed otoscope was evaluated by the measured illuminance.","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122646394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Illumination of KOIZUMI R&D Center","authors":"Kotaro Kawano, H. Arita, Hitoshi Kitamura, J. Kanazawa","doi":"10.2150/jstl.ieij19a000003","DOIUrl":"https://doi.org/10.2150/jstl.ieij19a000003","url":null,"abstract":"","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133385486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Directional and Diffused Lights on the KANSEI Evaluation of a Glossy Object and the Scene","authors":"Shoichi Tamane, Tomoharu Ishikawa, Mie Sato, Y. Mizokami, M. Ayama","doi":"10.2150/jstl.ieij190000636","DOIUrl":"https://doi.org/10.2150/jstl.ieij190000636","url":null,"abstract":"Advances of lighting technology make it possible to realize various types of space lighting from strongly directional to highly uniform. In this study, the effect of mixture ratio of directional and diffused light on KANSEI evaluations of the object and scene, black lacquer bowl with tofu sample in nearly uniform and achromatic background is investigated. Subjective evaluations were carried out under various lighting conditions using 15 adjective pairs, such as “ Non-glossy vs Glossy ” , “ Soft vs Hard ” , and “ Ugly vs Beautiful ” , etc., that were selected in the pre-experiment. Results of the subjective evaluation for the adjective pairs are divided into 3 groups in relation to lighting quality. Group 1 that reflect surface property of the object such as “ Non-glossy vs Glossy ” , correlate primarily to highlight luminance with mild correlation to the luminance of non-highlight area, whereas those of Group 2 that reflect nonvisual physical properties such as “ Soft vs Hard ” , correlate primarily to the luminance of non-highlight area with almost no effect from directional light. Adjective pairs of Group 3 that reflect to higher order values of object and/or scene such as “ Cheap vs Luxury ” or “ Realistic vs Fantastic ” , correlate strongly to the luminance contrast between highlight and non-highlight areas.","PeriodicalId":328826,"journal":{"name":"Journal of Science and Technology in Lighting","volume":"52 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120890887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}