Patent ID: 7588838

Claim:
An electroluminescence device, comprising: a luminescent layer having a multitude of electroluminescent particles distributed in a binder, said particles forming at least a first particle group and a second particle group; and electrodes for applying a voltage to said luminescent layer, wherein each of the electroluminescent particles forming said first particle group comprises a dielectric core having a first dielectric constant and a fluorescent coating layer made of a first fluorescent material, each of the electroluminescent particles forming said second particle group comprises a dielectric core having a second dielectric constant which is different from said first dielectric constant and a fluorescent coating layer made of a second fluorescent material, said first and second fluorescent materials are fluorescent materials that produce different luminescent colors from each other, and said first dielectric constant and said second dielectric constant are selected based on properties of the fluorescent coating layers, such that said first particle group and said second particle group have a substantially identical apparent voltage-brightness characteristic or a substantially identical deterioration pattern of an emission lifetime.