| 摘要 |
The difference of luminance between a front surface side and a rear surface side as viewed from the front surface side is reduced in a multi-layered EL lamp. An EL lamp includes a first laminate formed by serially laminating a first transparent electrode, a first luminescent layer and a first insulating layer, a second laminate formed by serially laminating a second transparent electrode, a second luminescent layer and a second insulating layer on the first laminate, and a rear electrode formed on the second laminate, wherein a dielectric constant between the first and second transparent electrodes is set to a value smaller than a dielectric constant between the second transparent electrode and the rear electrode. This can be achieved by limiting the amount of a high dielectric material to be mixed in the first insulating layer to not greater than 90% in terms of a weight ratio of a high dielectric material mixed in the second insulating layer, or by increasing the thickness of the first luminescent layer to 130 to 250% of the thickness of the second luminescent layer. After the adjustment is made in this way, the thickness of the first insulating layer may be set to not greater than 90% of the thickness of the second insulating layer or may be omitted.
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