Light emitting device and plant cultivation method

A method of using a light emitting device for red light supplement, the method comprising combining the light emitting device with a second white LED light emitting device,

• wherein the light emitting device comprises:
• a light emitting element having an emission peak wavelength in a range of 380 nm or more and 490 nm or less, and
• a red fluorescent material which is excited by light from the light emitting element to emit light having at least one light emission peak wavelength in a range of 580 nm or more and less than 680 nm,
• wherein a ratio of a photon flux R of red light in a range of 620 nm or more and 700 nm or less to a photon flux B of blue light in a range of 400 nm or more and 490 nm or less, R/B, is in a range of more than 20 and 200 or less, and
• wherein the second white LED light emitting device comprises a light emitting element having an emission peak wavelength in a range of 380 nm or more and 490 nm or less, a green fluorescent material, a yellow fluorescent material and a red fluorescent material.

A method of using a light emitting device for red light supplement, the method comprising combining the light emitting device with a first white LED light emitting device,

• wherein the light emitting device comprises
• a light emitting element having an emission peak wavelength in a range of 380 nm or more and 490 nm or less, and
• a red fluorescent material which is excited by light from the light emitting element to emit light having at least one light emission peak wavelength in a range of 580 nm or more and less than 680 nm, wherein:
• a ratio of a photon flux R of red light in a range of 620 nm or more and 700 nm or less to a photon flux B of blue light in a range of 400 nm or more and 490 nm or less, R/B, is in a range of more than 20 and 200 or less, and
• wherein the first white LED light emitting device comprises a light emitting element having an emission peak wavelength in a range of 380 nm or more and 490 nm or less, a yellow fluorescent material and a red fluorescent material,
• wherein when the photon flux of blue light, as calculated through integration of photon flux data in a range of 400 nm or more and 490 nm or less, is referred to as 1, a photon flux G of green light, as calculated through integration of photon flux data in a range of more than 490 nm and 570 nm or less, is 1.7, and
• wherein the two devices are so combined that a ratio of a photon flux Rmix of red light in a range of 620 nm or more and 700 nm or less to a photon flux Rmix of blue light in a range of 400 nm or more and 490 nm or less of a mixed light of light emitted by the light emitting device and light emitting by the first white LED light emitting device, Rmix/Bmix is 3.5.

A method of using a light emitting device for red light supplement, the method comprising combining the light emitting device with a second white LED light emitting device,

• wherein the light emitting device comprises:
• a light emitting element having an emission peak wavelength in a range of 380 nm or more and 490 nm or less, and
• a red fluorescent material which is excited by light from the light emitting element to emit light having at least one light emission peak wavelength in a range of 580 nm or more and less than 680 nm, wherein:
• a ratio of a photon flux R of red light in a range of 620 nm or more and 700 nm or less to a photon flux B of blue light in a range of 400 nm or more and 490 nm or less, R/B, is in a range of more than 20 and 200 or less, and
• wherein the second white LED light emitting device comprises a light emitting element having an emission peak wavelength in a range of 380 nm or more and 490 nm or less, a green fluorescent material, a yellow fluorescent material and a red fluorescent material,
• wherein when the photon flux of blue light, as calculated through integration of photon flux data in a range of 400 nm or more and 490 nm or less, is referred to as 1, a photon flux G of green light, as calculated through integration of photon flux data in a range of more than 490 nm and 570 nm or less, is 1.7, and
• wherein the two devices are so combined that a ratio of a photon flux Rmix of red light in a range of 620 nm or more and 700 nm or less to a photon flux Rmix of blue light in a range of 400 nm or more and 490 nm or less of a mixed light of light emitted by the light emitting device and light emitted by the second white LED light emitting device, Rmix/Bmix is 3.5.