著者

Tomohiro Jishi Kazuhiro Fujiwara Kyohei Nishino Akira Yano

出版者

The Illuminating Engineering Institute of Japan

雑誌

Journal of Light & Visual Environment (ISSN:03878805)

巻号頁・発行日

vol.36, no.3, pp.88-93, 2012-12-01 (Released:2013-03-04)

参考文献数

9

被引用文献数

3 12

---

The CO2 uptake rate (CUR) of the aerial part of cos lettuce (Lactuca sativa) was measured in pulsed and continuous light at an average photosynthetic (wavelength range: 400–700 nm) photon flux density (PPFD) of 100 μmol m-2 s-1 from white light-emitting diodes (LEDs). Three duty ratios of 25, 50, and 75%, combined variously with eight frequencies of 0.1, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, and 12.8 kHz were used for pulsed light irradiation. The CURs were significantly lower at a duty ratio of 50% for frequencies of 0.1–0.8 kHz and at a duty ratio of 25% for all frequencies than those in continuous light although the average PPFD was unchanged. These results indicate that pulsed light at lower duty ratios, combined with lower frequencies, makes CUR of cos lettuce lower than that attained in continuous light. We infer, based on a PPFD-CUR curve obtained with cos lettuce plant used in the experiment, that when greater PPFD is provided, pulsed light at lower duty ratios with lower frequencies is less advantageous than continuous light for photosynthesis.

著者

John D. Bullough Nicholas P. Skinner Kathryn SWEATER Hickcox

出版者

(一社)照明学会

雑誌

Journal of Light & Visual Environment (ISSN:03878805)

巻号頁・発行日

vol.37, no.4, pp.189-193, 2013-03-31 (Released:2014-04-18)

参考文献数

12

被引用文献数

4

---

Even when not directly visible, flicker from light sources at frequencies exceeding 100 Hz can influence perception through stroboscopic effects. Three experiments were conducted to evaluate the impacts of flicker varying in frequency and modulation depth on visual performance, comfort and preference. In one experiment, subjects performed a numerical verification task under flickering illumination from 100 to 1000 Hz and from 25% to 100% flicker. Error rates were lower under higher frequency and lower flicker modulation and visual comfort was slightly higher. In the second experiment, subjects preferred higher frequency and lower modulation than 100 Hz, 100% flicker. In the third experiment, subjects equated perceived quality from illumination with higher frequency or lower modulation flicker when the illuminance was reduced by about half, relative to 100 Hz, 100% flicker. The results were consistent with a recently published model of the perception of stroboscopic effects.

著者

Yoshinobu NAYATANI Hiroaki SOBAGAKI Kenjiro HASHIMOTO

出版者

The Illuminating Engineering Institute of Japan

雑誌

Journal of Light & Visual Environment (ISSN:03878805)

巻号頁・発行日

vol.17, no.2, pp.2_16-2_24, 1993 (Released:2011-02-25)

参考文献数

21

被引用文献数

6 7

---

Using the nonlinear color-appearance model, predicted are the four kinds of color-perception phenomena, which are the Go function studied by Evans, Munsell Values for different hues, purity discrimination, and the Helmholtz-Kohlrausch effect. The analysis confirmed that all the four phenomena are caused by the same common factor, the chromatic strength of spectral color stimulus reported by Evans in 1967.

著者

Naoya HARA Ichiro NAMBA Tarow NOGUCHI

出版者

The Illuminating Engineering Institute of Japan

雑誌

Journal of Light & Visual Environment (ISSN:03878805)

巻号頁・発行日

vol.27, no.3, pp.165-171, 2003 (Released:2004-01-23)

参考文献数

7

被引用文献数

8 10

---

The purpose of this study is to obtain data based on the readability of chromatic documents for use in visual environment design. That data would seem to be the same as the existing data based on the readability of achromatic documents. Experiments are undertaken in order to clarify the influence of color on readability. The results show that the same CIELAB color difference does not have the same influence on readability. In addition, it is thought that the equivalent luminance contrast is invariable irrespective of the size of a letter and is instead determined by the combination of the colors of the letters and the background. It is suggested that the readability of chromatic documents can be estimated by using the equivalent luminance contrast and the existing relationship between the visual factors and readability of achromatic documents.

著者

Kanji KATORI Masahiro FUWA

出版者

The Illuminating Engineering Institute of Japan

雑誌

Journal of Light & Visual Environment (ISSN:03878805)

巻号頁・発行日

vol.9, no.1, pp.1_22-1_32, 1985 (Released:2011-05-20)

参考文献数

12

被引用文献数

3 3

---

With a view to developing a new photometric system which will give a better agreement with the visual impression of the light, the effects of both the visual field sizes and the criteria for measurement of spectral luminous efficiency functions on the shapes of the functions were examined in the case of 2° and 10° fields, by applying two different methods, flicker photometry and direct heterochromatic brightness matching, using the same white reference. A 2° field function by flicker photometry was very similar to Judd’s modified V(λ) function while a 2° field function by direct heterochromatic brightness matching showed hilly humps on both sides of 570 nm. A 10° field function by flicker photometry showed no significant differences from both the CIE y10(λ) and the ETL y10(λ) functions derived from the color matching functions. These findings suggest that the CIE y10(λ) function should be used as a standard photometric observer in the large visual field. A 10° field function by direct heterochromatic brightness matching showed the largest values among the four relative spectral luminous efficiency functions over the whole range of visible wavelengths. The relative spectral luminous efficiency data obtained by heterochromatic brightness matching for the 2° and 10° fields here will provide data useful for development of a new photometric system where a great importance is to be attached to a correspondence between sensation of brightness and photometric quantity.

著者

John D. BULLOUGH Ramesh RAGHAVAN Richard M. PYSAR Yukio AKASHI

出版者

The Illuminating Engineering Institute of Japan

雑誌

Journal of Light & Visual Environment (ISSN:03878805)

巻号頁・発行日

vol.31, no.1, pp.19-24, 2007 (Released:2007-06-08)

参考文献数

18

被引用文献数

1

---

Temporal characteristics of fluorescent lighting systems during starting might affect their acceptance in commercial and residential lighting. The immediate, full onset of light is usually experienced when switching on incandescent lamp systems. For certain systems using fluorescent lamps, delayed onset or initially low light levels might be experienced. Such characteristics could make them unwelcome additions to commercial and residential settings. The results of a study to investigate subjective and behavioral responses to lighting systems having different temporal characteristics upon start-up are presented.