High color rendering compact HID lamps are being used for indoor lighting.
This is because HID lamps have higher efficiency and longer life than those of incandescent and tungsten halogen lamps. Also HID lamps are more compact and have higher lumen output when compared to fluorescent lamps.
In the future lamp safety will be a important factor, particular being paid to the following areas--
* Shattering. *Ultra violet radiation. *High starting voltage.
It is also expected that higher color rendering is required especially in the red (R9).
The double ended metalhalide lamp is one type of those HID lamps, with acolor temperature of 3000K and 4300K. However the color rendering index (Ra) of both of these lamps was lower than 90.
Dy-T1-I type lamp has excellent color rendering with Ra 90 or more, but the color temperature is high at approximately 6000K.
We tried to lower the color temperature without reducing the Ra, which is particularly important for interior lighting, so it was considered that Ra of 90 or more and R9 of 50 or more was essential.
We developed the 150W Dy-Tl-I type compact metalhalide lamp which has the desirable color temperature around 4300K and excellent color rendering, Ra 90 and R9 of 84. New lamp also designed more safty, about shattering, UV radiation and high starting voltage.

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By increasing the lamp wattage, a number of fixtures can be reduced or higher illuminance can be achieved.
It is well known that kripton filling lamp shows higher luminous efficacy, while it has higher starting voltage and higher lamp current. Oppositely argon filling lamp has lower lamp current that reduces ballast loss and gives higher luminous flux as a result of higher lamp wattage.
Highly loaded T8-1.2m argon lamp shows fairly good luminous efficacy when operated by electronic ballast.For instance, 40W T8 lamp shows over 100 lm/W which is competitive with 102 lm/W of standard 32W T8 lamp.
To prevent the sputtering of the emmision materials, filament preheating up to the temperature of glow-to-arc transition is important.

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It is fitting to celebrate this Diamond Jubilee at the start of the last decade of both a century and a millenium. For the Japanese millenia have come and gone but lighting has seen a revolution this century. Although the Institute appeared long after Sir Joseph Swan's invention of the electric lamp, the use of Kansai bamboo by Thomas Edison marked Japan's early contributions to lighting technology. From those beginnings we all moved steadily but placidly until the ten years of the first “energy crisis” produced more new light sources than had the hundred years since Edison's commercial product, the “wire in the bottle”.
But technology alone, is not the answer in lighting. Light and vision are far too important in our lives to depend solely upon hardware. It is design (or the lack of it) which determines where light falls and how it affects our senses. The best possible design can make our lives better and safer, our homes andwork places moreattractive, and provide the energy management and conservation which is required as we approach the end of the century.
However, energy bureaucrats must not be permitted to “turn out the lights”! Token gestures which suggest, but may not produce, lighting conservation must not interfere with modern industries which substitute the muscles of our eyes for the muscles of our backs. No amount of electrical energy saved is worth an increased expenditure of human visual energy. The nightscape must not be taken from us as we achieve the leisure to enjoy it.
The years through 2000 will see improvements in lamp technology and controls. Will they see equal research on light, vision, and colour and on user acceptance of the lighting Changes which design, technology, and conservation must bring?
Research that keeps human needs in step with lighting technology can lead us all into a new century of lighting excellence which will match the achievements of the Japanese Institute's past seventy-five years.

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