Lighting device
AssigneeHitachi, Ltd.
InventorKeiichi F. Komatsubara
Life of this patent
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Abstract
A lighting device is provided for emitting superradiant fluorescent light. First material layers are provided which emit predetermined electromagnetic waves of spontaneous emission when supplied with a predetermined energy (e.g. a pumping ray or beam). Second material layers, transparent to the electromagnetic wave, are stacked between the layers of the first material. To provide an improved light emission, the second material layers are arranged so that the interspaces l between the first material layers are smaller than c.multidot..tau..sub.R, where c is the velocity of said electromagnetic wave and .tau..sub.R is a time constant of the spontaneous emission.
Claims13
A lighting device comprising:
- first material layers emitting a predetermined electromagnetic wave of spontaneous emission;
- second material layers substantially transmitting said electromagnetic wave, each of which is stacked between said first material layers so that interspaces l between said first material layers are smaller than c.multidot..tau..sub.R, where c is the velocity of said electromagnetic wave and .tau..sub.R is a time constant of the spontaneous emission;
- and
- means for supplying said first material layers with a predetermined energy so that the spontaneous emission is caused in said first material layers.
A lighting device comprising:
- a plurality of fluorescent material layers emitting an electromagnetic wave of spontaneous emission;
- a plurality of transparent material layers formed alternately with said fluorescent material layers so as to make each of interspaces between said fluorescent material layers have a length l not larger than c.multidot..tau..sub.R where c is a photon velocity of said electromagnetic wave and .tau..sub.R is a time constant of the spontaneous emission;
- and
- means for supplying energy to said fluorescent material layers so as to cause population inversion of electrons in said fluorescent material layers.
Dependencies are inferred from the claim text.