Light emitting device

A light emitting device comprising:

• a board;
• a plurality of first light emitting elements mounted on the board to emit light having a wavelength of 250 nm to 500 nm;
• a plurality of second light emitting elements mounted on the board to emit light having a wavelength of 250 nm to 500 nm;
• a first fluorescent layer formed on each of the first light emitting elements, the first fluorescent layer including a first phosphor;
• and
• a second fluorescent layer formed on each of the second light emitting elements, the second fluorescent layer including a second phosphor being higher than the first phosphor in luminous efficiency at 50° C., being lower than the first phosphor in the luminous efficiency at 150° C.,
• wherein packaging density of the first light emitting elements in a first region of the board is higher than that of the second light emitting elements in a second region.

A light emitting device comprising:

• a board;
• a plurality of first light emitting elements mounted on the board to emit light having a wavelength of 250 nm to 500 nm;
• a plurality of second light emitting elements mounted on the board to emit light having a wavelength of 250 nm to 500 nm;
• a first fluorescent layer formed on each of the first light emitting elements, the first fluorescent layer including a first phosphor;
• and
• a second fluorescent layer formed on each of the second light emitting elements, the second fluorescent layer including a second phosphor being higher than the first phosphor in luminous efficiency at 50° C., being lower than the first phosphor in the luminous efficiency at 150° C.,
• wherein the first light emitting elements are mounted on a first region of the board,
• the second light emitting elements are mounted on a second region of the board, and
• wherein the first region is surrounded by the second region.

A light emitting device comprising:

• a board;
• a plurality of first light emitting elements mounted on the board to emit light having a wavelength of 250 nm to 500 nm;
• a plurality of second light emitting elements mounted on the board to emit light having a wavelength of 250 nm to 500 nm;
• a first fluorescent layer formed on each of the first light emitting elements, the first fluorescent layer including a first phosphor;
• and
• a second fluorescent layer formed on each of the second light emitting elements, the second fluorescent layer including a second phosphor being higher than the first phosphor in luminous efficiency at 50° C., being lower than the first phosphor in the luminous efficiency at 150° C.,
• wherein the first light emitting elements are mounted on a first region of the board,
• the second light emitting elements are mounted on a second region of the board, and
• wherein a thermal resistance of the board in the first region is larger than that of the board in the second region.