Semiconductor light-emitting devices such as LDs (semiconductor laser diodes) and LEDs are widely used in display devices, lighting apparatuses, recording apparatuses, etc. Recently, as a new application of semiconductor light-emitting devices, development of solid-state lighting has been advanced. When semiconductor light-emitting devices are used to replace existing incandescent lamps, there are advantages in that efficiency is high and heat generation is low. Thus, promotion of the replacement is considered to continue.
However, in a white light-emitting apparatus in which a semiconductor light-emitting device and phosphors are combined, a phenomenon of a decrease in light extraction efficiency is exhibited that is caused by occurrence of reabsorption between the phosphors due to the phosphors being not disposed ideally. In addition, a phenomenon is exhibited in which the color of light emission differs depending on the irradiation direction, and thus, the color looks different depending on the irradiation direction.
For example, to avoid reabsorption between phosphors, there is proposed a light-emitting apparatus in which a plurality of phosphors are arranged on a plane so as not to overlap each other in an optical path direction. In addition, for example, there is disclosed a light-emitting apparatus in which by making the distance of a phosphor plate variable with respect to an LED, the irradiation pattern is changed and the color temperature is made variable.
However, forming a plurality of phosphors on a plane such that the phosphors do not overlap each other is difficult in terms of fabrication. In particular, it can be said that fabricating a fine structure is extremely difficult.
USPTO Backgrounds
USPTO Backgrounds