著者

森田 政明 洞口 公俊 山本 修司 片山 就司

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.87, no.12, pp.986-991, 2003-12-01 (Released:2011-07-19)

参考文献数

14

著者

笠井 幹治

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.64, no.11, pp.624-626, 1980-11-01 (Released:2011-07-19)

参考文献数

6

著者

中山 和美 乾 正雄 佐藤 仁人 國友 美希

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.84, no.2, pp.100-106, 2000-02-01 (Released:2011-07-19)

参考文献数

3

被引用文献数

1 2

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This study was conducted to clarify the difference in visual acuity and color recognition between the darker color eyes of Japanese and the fairer color eyes of Westerners at lower illuminance. A series of experiments were carried out in an experimental room in which the illuminance level could be changed. The parameters were the illuminance on a desk and the color of the subject's eyes. Ten illuminance levels, which increased geometrically from 0.001 to 30 lx, were used. The subjects comprised two groups having different eye colors. One group was made up of Japanese, who have dark eyes, and the other Europeans and North Americans with fair eyes. At each illuminance level, after 7 minutes for adaptation, each subject's visual acuity was tested using 4 types of color Landolt rings and color discrimination was tested using 12 different-color cards. The following results were obtained.(1) For a black Landolt ring on a white background, there was very little difference between the two groups' visual acuity.(2) For a green Landolt ring on a blue background, the visual acuity of the dark-eyes group was remarkably lower than that of the fair-eyes group.(3) In the color discrimination test, at an illumination of 1 lx or lower, the dark-eyes group confused colors more than the fair-eyes group.Accordingly, the differences in visual acuity and color discrimination between the two eye-color groups were only in color discrimination at lower illuminance.

著者

藤澤 泰充 橋本 守 荒木 勉

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.81, no.8, pp.656-663, 1997-08-01 (Released:2011-07-19)

参考文献数

10

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Temporal emission characteristics of light emitting diodes (LEDs) for high-speed repetitive current have been investigated. For this purpose, three commercially available LEDs (red, green and blue LEDs) were prepared. Each LED was driven by a specially designed pulse generator constructed using an avalanche transistor to generate high-speed pulse current. Resultant injection current showed a nanosecond duration pulse with peak height of a few amperes. Time responses and spectral profiles of the emission waveforms were measured with respect to the pulsed current. Resultant light durations of the pulsed LEDs were in the nanosecond range. When the injection current increased, the peak emission intensity of the LED increased without saturation. In particular, the ultraviolet component of the blue LED became evident, resulting in peak emission intensity of 30 m W with duration of 5 ns. Lifetime of the pulse-operated LED was over 1O 10 shots, which corresponds to 140 hours running at repetition frequency of 20 kHz.

著者

吉田 忠一 寺尾 善弘 山本 正治

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.72, no.7, pp.367-370, 1988-07-01 (Released:2011-07-19)

参考文献数

6

著者

小野 博之

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.86, no.4, pp.227-232, 2002-04-01 (Released:2011-07-19)

参考文献数

5

被引用文献数

1

著者

吉田 忠一 寺尾 善弘 山本 正治

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.72, no.5, pp.275-278, 1988-05-01 (Released:2011-07-19)

参考文献数

6

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.76, no.3, pp.plate1-plate6, 1992-03-01 (Released:2011-07-19)

著者

向 健二

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.87, no.3, pp.202-205, 2003-03-01 (Released:2011-07-19)

参考文献数

4

著者

角津 敏之

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.86, no.12, pp.906-908, 2002-12-01 (Released:2011-07-19)

著者

向阪 信一 山中 泰彦

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.76, no.7, pp.361-363, 1992-07-01 (Released:2011-07-19)

参考文献数

7

著者

伊東 孝

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.72, no.5, pp.246-250, 1988-05-01 (Released:2011-07-19)

参考文献数

3

著者

武内 徹二

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.81, no.6, pp.500-505, 1997-06-01 (Released:2011-07-19)

参考文献数

17

被引用文献数

1 1

著者

城内 忠志 田中 哲治 石崎 勝司

出版者

一般社団法人照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.83, no.12, pp.922-925, 1999-12-01

被引用文献数

1

著者

高桑 祐吉

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.71, no.3, pp.210-214, 1987-03-01 (Released:2011-07-19)

参考文献数

7

著者

栗木 一郎 石井 渉 内川 恵二

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.84, no.2, pp.107-116, 2000-02-01 (Released:2011-07-19)

参考文献数

13

被引用文献数

7 3

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We conducted four kinds of psychophysical measurements on color vision to investigate whether the change in lens spectral transmittance that comes with aging is the primary factor in the change in color vision. We asked two observers (22 and 24 years old) to adapt to the scene while wearing goggles equipped with filters that simulate spectral transmittance at the retinal level of a person of 80 years old, when worn by 20 years old observer. During the test, which lasted as long as 12 hours, the observers performed (1) unique-white setting, (2) heterochromatic flicker photometry (HFP), (3) heterochromatic brightness matching (HBM), and (4) 100-hue test. The change in the results with and without the goggle showed that only difference in HFP sensitivity coincided exactly with the filter transmittance. A similar tendency was found in the difference between 20 and 80year-old observers in a previous study. The other tests matched with neither the difference in spectral transmittance nor the difference between 20-and 80year-old experimental results. Our results suggest that neural circuits, which may differ from those for illuminant change, play a significant role in correcting the relative spectrum change on the retina.

著者

角取 猛司

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.72, no.5, pp.273-274, 1988-05-01 (Released:2011-07-19)

著者

稲垣 襄二

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.71, no.7, pp.370-374, 1987-07-01 (Released:2011-07-19)

参考文献数

17

著者

大西 まどか 小田 浩一

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.101, no.10, pp.474-483, 2017-10-01 (Released:2017-12-01)

参考文献数

36

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This study aims to explain as quantitatively as possible the readability of Japanese characters in terms of certain elements in the multi-dimensional, and rather qualitative, space of font design. Based on a review of previous studies, two main dimensions have been selected as the most influential on readability ; the relative character size in the bounding box, which we call style, and the stroke width, which we call weight (when discussed in a categorical way). The Gothic fonts were chosen as the target because they are well known to be the most legible. Behavioral evaluations of readability were conducted instead of subjective judgments. In accordance with the reading acuity measurement MNREAD-J, short and easy-to-read sentences were presented to participants, and the time required to read them aloud was recorded along with any reading errors ; this provided three readability indices. Sentences were rendered in one of 12 different fonts consisting of four kinds of style-Old, Standard, Modern, and UD-times three weight levels-Light, Regular, and Bold. Findings for the style suggest that the enlargement of relative size represents a tradeoff with narrowed inter-letter spacing. This means that good legibility of single letter design may not result in good readability of letters in sentences. However, the weight had a notable effect especially in small sizes. Two readability indices were predicted relatively well by participants’ acuity and stroke width. The effect of stroke width had a ceiling between 10 and 15 % of the letter size.

著者

瀬川 かおり 内川 恵二 栗木 一郎

出版者

一般社団法人 照明学会

雑誌

照明学会誌 (ISSN:00192341)

巻号頁・発行日

vol.83, no.11, pp.860-868, 1999-11-01 (Released:2011-07-19)

参考文献数

22

被引用文献数

6 7

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We can perceive small color differences, and we can also perceive color as a group of many different colors (categorical color perception). Visual performances based on small color differences are known to be better in the central visual field than in the periphery. We have clarified the characteristics of categorical color perception in the peripheral visual field. Observers were shown color chips of the OSA Uniform Color Scales set in the central or the peripheral visual field. The chip, which subtended 4deg, was presented at the fovea (Odeg), eccentricities of 30, 50, and 60 deg in the nasal visual field and of 30, 50, 70, 80, and 90 deg in the temporal visual field. A large gray surrounding field was made with a hemisphere and illuminated at a moderate intensity of D65 lights (yielding 2000 scotopic td) to suppress rod activity. The observers reported color appearance of the stimulus with one of the eleven basic color terms. The distributions of the color categories on the xy chromaticity diagram varied little between stimulus locations from 30 deg to the nasal and 70 deg to the temporal visual field. The results of eccentricities greater than nasal 50 deg and temporal 80 deg were remarkable different from those in the locations closer to the fovea. Our results suggest that categorical color perception in the central visual field is maintained across a wide area of the peripheral visual field.