An Experimental Study on Evaluating Glare in Blue
Light Exposure
Daisuke Miyazaki, Kimi Ueda, Soma Kawamoto, Wakako Takekawa, Hirotake Ishii, Hiroshi Shimoda
Graduate School of Energy Science, Kyoto University, Japan
2019/7/26 1
Introduction
• How to improve work performance in an office• by controlling indoor environment
• Exposure to blue light improves human arousal
2
Control indoor
environment
Improve arousal
Improve work
performance
temperature, air flow, lighting
Experiment Result ConclusionIntroduction
Blue Light
• Photoreceptors in the retina called melanopsin cells*• improve human arousal when stimulated
• have spectral sensitivity peaks around the wavelength of 480nm
3
Experiment Result Conclusion
retina
Melanopsin cells
Blue Light Improve arousal
Improve work
performance
*Provencio, I., Jiang, G., Grip, W., Hayes, W., Rollag, D.: Melanopsin: An opsin in melanophores, brain and eye. In: PNAS, Vol. 95, No. 1, pp. 340-345 (1998)
Introduction
Previous Study*
• An experiment was conducted• to evaluate the intellectual concentration improvement
effect by blue light exposure
• As the result,• the feeling of dazzling disturbs intellectual work
4
Experiment Result Conclusion
Blue light exposure
Cause the feeling of dazzling
disturb intellectual
work
*Miyazaki, D., Ueda, K., Kawamoto, S., Takekawa, W., Ishii, H., Shimoda, H., Yabuki, J., Uchida, T., Noguchi, H.: An Experimental Study on Intelligent Concentration Improvement by Blue Light Exposure. In: Proc., Human Interface Symposium 2018 (2018) (In Japanese)
Introduction
Purpose of this Study
• to find which blue light conditions cause feeling of dazzling or disturb intellectual work
• four blue light conditions (shown in next slide)• changing Luminance and Light emitting area
5
Experiment Result Conclusion
Experience Blue Light Conditions
Answer questionnaire
about glare
Evaluate the degree of
glare
Experiment
Introduction
Light Conditions in the Experiment
6
Introduction Result Conclusion
(a) 1 unit 100% luminance output (b) 2 units 50% luminance output
(c) 4 units 25% luminance output (d) 8 units 12.5% luminance output
• Total amount of blue light is the same in all conditions
Experiment
Cognitive Task
7
Introduction Experiment Result Conclusion
UNDO
Meaning category
same differentcorrectwrong
Ineq
ual
ity
ID : 01Finish
PEACH : SOCKS
6742 < 6675
• Comparison Task
Procedure of Experiment
• 25 university students• males from 19 to 26 ages with normal eye sight
8
Introduction Result Conclusion
AnswerPhysical Condition questionnaire and Glare questionnaire
Practice
5
Rest
10
Explanation
15
Rest
10
SET1
5
SET2
5
Rest
10
SET3
5
Rest
10
SET4
5
Total : 90min.
Finalquestion
naire
10
(min.)
Experiment
Questionnaire
• Physical Condition questionnaire• subjective fatigue, arousal, concentration with 100 grades
• Glare questionnaire• subjective dazzling of each light condition with 9 grades
(shown in next slide)
• Final questionnaire (choice and free description)• which conditions were distractive
• which conditions were not acceptable
9
Introduction Result ConclusionExperiment
Glare Questionnaire*
10
Introduction Result Conclusion
*BGI(British Daylight Glare Index): Technical Report No. 10, IES-London, 1967.
• Circle one number to answer
Imperceptive
Perceptible but not unacceptable
Unacceptable but not uncomfortable
Uncomfortable but not intolerable
Intolerable9
8
7
6
5
4
3
2
1
Experiment
Result of Glare Questionnaire
11
Introduction Experiment Conclusion
1
2
3
4
5
6
7
8
9
1台 2台 4台 8台
blue light conditions
1 unit 2 units 4 units 8 units
5.6 1.6
4.2 1.84.8 1.5 4.8 2.0
(a) 1 unit (b) 2 units
(c) 4 units (d) 8 units
Dazzling
Result
Intolerable
1 unit 2 units 4 units 8 units
the number of answers 11 3 6 8
Result of Final Questionnaire
12
Introduction Experiment Conclusion
Distractive
1 unit 2 units 4 units 8 units
the number of answers 17 10 8 8
because light emitting area was large
because intense light was exposed
asymmetrically asymmetry
Result
Conclusion
• Measured the subjective evaluation of glare
• As the result, 3 factors cause feeling of dazzling• Luminance
• Asymmetric irradiation
• Light emitting area
• In the four light conditions,• 2 units condition is the best in the point of glare
13
Introduction Experiment Result Conclusion