• KIEAE Journal
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• 제7권6호
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• pp.37-43
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• 2007

Discomfort glare is an important factor influencing appraisal for lighting environment. Unified Glare Rating (UGR) which has been proposed by CIE is one of the formula for evaluating discomfort glare. Position index is an important factor in the UGR formula. Position index was proposed by Guth in 1949. It has been used until present limiting upper visual field. Lower visual field has different sensation of brightness in comparing with upper visual field. Therefore, it is necessary to propose position index about lower visual field. The objective of this study is to investigate the brightness sensation in upper and lower visual field. First, the visual field was measured on the self-made Glare Tester. Second, luminance of the Borderline between Comfort and Discomfort (BCD) was measured on the glare Tester. Circular sources of brightness were located at various angular distances from the line of vision along five meridians, $0^{\circ}$, $45{\circ}$, $90{\circ}$, $-45{\circ}$, $-90{\circ}$. The size of the glare source is 0.0011sr. The luminance of the surrounding field, which extended over the entire visual field, was maintained $34ccd/m^2$. Ten subjects aged from 25 to 29 were participated in the experiment. The results show that the luminance of BCD on the line of vision is $4337cd/m^2$ and the glare sensation of the lower visual field is more sensitive than the upper visual field.

• KIEAE Journal
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• 제7권5호
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• pp.29-34
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• 2007

Discomfort glare from windows is an important issue in window and daylighting design. This study aims to investigate the effect of luminance difference between the lower and the upper part of a large glare source. Experiments were conducted using a luminous body divided into two parts, the upper part and the lower part. The degree of discomfort glare from the luminous body was examined. The result shows that the part with lower luminance is perceived as a glare source when the part has higher luminance then the background luminance. The degree of discomfort glare was estimated for the experimental conditions, and compared to the observations. The estimation was made using two methods: one summed the glare sensation for each section, and the other used the average luminance of the whole luminous body. The result of the comparison shows that the method using the average luminance has approximate values to the observations. Consequently, the use of the average luminance was proposed for evaluation of discomfort glare from non-uniform large glare sources.

• 설비공학논문집
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• 제23권1호
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• pp.61-72
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• 2011

The influences of luminous environment on visual responses and fatigue sensation in art galleries were examined in this study. Field measurements and survey were performed in three galleries under various illuminance and luminous conditions. Result implies that vertical illuminance on art paintings needed to be somewhere between 200 lx and 300 lx to avoid visual discomfort. The vertical illuminance difference between consecutive paintings should not exceed 100 lx to keep visually comfortable environment. Visual comfort sensations were related to glare, visual stimulus, reflection from paintings, illuminance variation, and the sensation that subjects can clearly see the paintings. The sensation of fatigue was significantly influenced by the changes of luminous element that caused visual stimulus and discomfort. The sensation of eye fatigue among physical fatigue was primarily influenced by the glare, visual stimulus and comfort. The psychological fatigue was also influenced by eye fatigue, visual comfort, brightness and satisfaction with color of light.

• 조명전기설비학회논문지
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• 제23권1호
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• pp.9-17
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• 2009

인공조명으로부터 유발되는 볼쾌글레어는 건강건축의 조명환경을 위한 중요한 평가요소이다. 글레어는 인간의 전체시야범위 내에서 휘도와 휘도대비에 의해 발생되는 감각으로서 정의되며, 시각적 작업을 수행하는 재실자에게 시작업의 방해를 일으켜 시각적 불쾌감을 유발할 수도 있다. 글레어는 글레어 광원의 위치, 글레어 광원의 밝기, 글레어 광원의 크기와 배경의 휘도에 의한 영향으로 평가될 수 있다. 따라서 변수를 제외한 나머지 요소들을 일정한 상태로 유지할 수 있는 실험기기가 글레어 평가를 위해 필요하다. 최근까지 글레어 평가기기의 성능한계로 인하여 글레어 요소들 간의 상관관계를 확인함에 있어서 제한이 있었다. 이에 선행연구를 참고하여 글레어 실험기기를 제작하고 이 기기를 글레어측정기기라고 명명하였다. 글레어측정기기는 지름 2[m] 반구형 스크린 내부 표면을 균일한 배경휘도 형성을 위해 흰색 무광택 도료로 마감하였으며, 광원들이 내부에 설치되어 있다. 글레어 광원은 $0{\sim}150,000[cd/m^2]$까지 조정이 가능하며 12개의 백열램프에 의한 배경휘도는 $0{\sim}350[cd/m^2]$까지 조정이 가능하다. 글레어 측정기기를 사용하여 피험자를 대상으로 시야범위 한계, 시선상의 BCD휘도와 상하부 시야에서의 BCD휘도 측정에 대한 연구가 진행되었다.

• 조명전기설비학회논문지
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• 제23권2호
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• pp.1-9
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• 2009

자연채광은 건물 재실자에게 시각적 편안함과 쾌적함을 제공하여 건강성을 향상시키며 조명 에너지를 절약할 수 있는 중요한 조명환경 요소이다. 자연광에 의해 발생되는 창면에서의 글레어는 장시간 노출될 시 시각의 저하, 시각적 불쾌감의 원인이 된다. 창면에 의한 불쾌글레어 평가시에는 창면에서 글레어 광원을 어떻게 선별할 것인가가 중요한 문제이다. 기존의 불쾌글레어 평가법을 적용하더라도 글레어 광원을 한정할 방법이 없다. 따라서 본 연구에서는 글레어 광원 선별방법을 모색하기 위하여 불균일한 대광원의 휘도차가 불쾌글레어감에 미치는 영향을 검토하였다. 이를 위하여 $120{\times}120[cm]$의 정사각형 모형창을 제작하였다. 실험변수는 균일과 불균일한 휘도분포의 광원의 휘도비와 광원크기로 선정하였다. 실험방법은 모형창을 3분할한 후, 각기 다른 휘도비를 설정하여, 1[m], 1.5[m], 3[m] 거리에서 불쾌글레어를 평가하도록 하였다. 실험 결과 두 개의 결론을 얻었다. 첫째, 광원의 평균휘도가 증가할수록 불쾌글레어 평가값이 증가하였으며, 둘째, 창면 상부의 천공 부분만을 글레어 광원으로 볼 수 없으며 하부면도 블쾌글레어 평가에 영향을 주는 것으로 나타났다. 본 연구의 결과는 채광창으로부터의 불쾌글레어 평가 시 글레어 광원을 선택하는 기준으로 활용될 수 있을 것이다.

• 설비공학논문집
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• 제22권8호
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• pp.553-561
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• 2010

This study examines the influence of light variation on visual responses in a small office space where a daylight dimming control system is applied. Field measurements and survey were performed in a full-scale mocked-up small office space under clear sky day conditions. Maximum fluctuation range for desktop was 133.5 lx and it just happened once for entire monitoring period. For the majority of time, the fluctuation range did not exceed 50 lx, which did not cause visual discomfort to subjects. The daylight dimming control system successfully kept required illuminance levels for an office environment when desktop illuminance by daylight ranged up to 300 lx. The most serious contributor to the sensation of glare was direct daylight through window. The dimming of electric light was not a significant contributor to visual discomfort for the subjects under clear sky day conditions. Visual comfort was significantly influenced by the sensation of glare, feeling for visual stimulation and distraction, and required illuminance level.

• 설비공학논문집
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• 제23권4호
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• pp.287-296
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• 2011

This study examines the influences of correlated color temperature and illuminance on visual perception and temporary mood sensation in a small office. Field measurements and surveys were conducted in a full-scale mock-up model. Twenty subjects participated in the survey under six lighting conditions formed by three color temperature and two illuminance levels. Results indicate that 4000 K color temperature was effective to mitigate glare sensation from light source. Lamps with low color temperature such as 2700 K was not recommended for office lighting since they are likely to caused glare and visual discomfort. Preferred color temperature was 4000 K and 6500 K for 750 lx and 500 lx target illuminance respectively. The increase of illuminance was not an effective contributor to improve mood perception. The illuminance should be lower than 500 lx to achieve good mood, but the illuminance level in office space should be considered with visual performance simultaneously. This study suggests that fluorescent lighting fixtures with 4000 K lamps would be usefully used for office lighting since they formed friendly conditions for better visual performance.