J. of IEIJ Vol.88, No.8A

The Abstracts of the Papers
J.Illum. Engng. Inst. Jpn. Vol. 88, 2004

No. 2 February
No. 5 May
No. 8A August
No. 11 November

Mode Transition between the Surface-Color and Aperture-Color Modes Caused by Changes in the Illuminance of a Space
Ichiro KATAYAMA, Kazuyoshi MASUMI and Tsutomu AOKI

Mode transition thresholds between the surface-color and the aperture-color modes of chromatic stimuli were examined. The luminance of the chromatic stimuli on a CRT display was kept constant, and the illuminance of an experimental booth including a subject was varied. The relationship between the mode transition thresholds and brightness-to-luminance (B /L) values of the stimuli was examined in experiment 1, and the relationship between them under a different illuminant was examined in experiment 2. The results of experiment 1 showed that the mode transition thresholds changed with the stimulus chromaticity and correlated highly with the B /L values of the stimuli. Moreover, the values of the mode transition thresholds depended upon not only the stimulus chromaticity but also the experimental method. That is, the values obtained with the constant chromatic stimuli method adopted in the present study were smaller than those with the variable chromatic stimuli method in previous studies. In addition, the results of experiment 2 showed that the mode transition thresholds correlated highly with the B /L values irrespective of the illuminant chromaticity. The results of experiments 1 and 2 lead us to the conclusion that mode transition perception is closely connected with a brightness perception mechanism.

KEYWORDS : color appearance, surface-color, aperture-color, mode transition, brightness-to-luminance ratio

Efficacy Improvement of Mercury-Free Xe Flat Discharge Fluorescent Lamps by Increasing Xe Partial Pressure
Tomokazu SHIGA, Tomokazu YOSHIKAWA, Shigeo MIKOSHIBA and Makoto YASUDA

The luminance and luminous flux of external-electrode, mercury-free,  Xe flat discharge fluorescent lamp for LCD backlights and lighting equipment are equivalent to those of conventional Hg fluorescent lamps. However its efficacy is lower. In this paper, improvement of efficacy was attempted.  First, the electrode width was reduced from 1.0mm to 0.5mm in order to widen the operating pressure margins. This enabled the Xe partial pressure to be increased from 1.2 kPa to 3.0 kPa, which increased efficacy 60%. Then a MgO, which has a high secondary electron emission coefficient, was coated on the dielectric layer, improving efficacy a further 10%. As a results, an efficacy of 35 lm/W with a luminance 10,100 cd/m2 were obtained with a 2.8-inch diagonal lamp.

KEYWORDS : mercury-free, fluorescent lamp, Xe discharge, luminous efficacy, LCD backlighting

Prediction Formula of Luminous Flux Maintenance for Fluorescent Lamps with Thicknesses of Phosphor Layer and Protection Film
Miho SAITO

Minimizing our negative on the environment is a global topics of interest. Achievement of high luminous flux. Maintenance is needed for the manufacture of environmentally friendly fluorescent lamps. At first, using multiple linear regression analysis, the relation of phosphor and protective layer thickness with the luminance flux maintenance is clarified. Next, the prediction formula of luminous flux maintenance is made and it is shown that a prediction formula agree with experimental results.

KEYWORDS : luminous flax maintenance, phosphor layer, thickness of a protective layer, multiple liner regression analysis, fluorescent lamp

Basic Study of Active Thermography Technique Using a FIR Heater
Kazutaka MITOBE, Yoon J HYUN, Yoshihisa KATAYOSE, Jun-ichi OGAWA and Noboru YOSHIMURA

KEYWORDS : far infrared rays, active thermography, natural zeolite, breast cancer, radiator

Evaluation on Color Rendering Effect of Landscape Lighting on Snowy District
Takahiro MATSUI, Mamoru TAKAMATSU, Yoshio NAKASHIMA and Yuukou HORITA

KEYWORDS : landscape lighting, color rendering effect, image estimation, semantic differential technique