| 摘要 |
PURPOSE:To obtain a sufficient ultraviolet ray and besides to improve light output characteristics in a visible region by forming a visible light emitting layer superposed on a visible light and ultraviolet ray emitting layer. CONSTITUTION:On the inner surface of a glass bulb is formed the first light emitting layer, on which the second light emitting layer is formed in superposition. The first light emitting layer is formed with a mixture of visible light emitting phosphor and 280-310nm ultraviolet ray emitting phosphor so that its diffuse transmission factor may become 85-95%. The second light emitting layer is formed with visible light emitting phosphor so that the overall diffuse transmission factor including the first layer may become 80-90%. Thereby, the illumination effect can be effectively improved without loss of health promoting effect owing to irradiation of 280-310nm ultraviolet ray. |
