US 12,464,621 B2
Light source device
Hiroyuki Yoshino, Tokyo (JP); and Tomokazu Sakashita, Tokyo (JP)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
Appl. No. 18/269,986
Filed by Mitsubishi Electric Corporation, Tokyo (JP)
PCT Filed Jan. 22, 2021, PCT No. PCT/JP2021/002208
§ 371(c)(1), (2) Date Jun. 28, 2023,
PCT Pub. No. WO2022/157917, PCT Pub. Date Jul. 28, 2022.
Prior Publication US 2024/0074017 A1, Feb. 29, 2024
Int. Cl. H05B 45/48 (2020.01); H05B 45/10 (2020.01)
CPC H05B 45/48 (2020.01) [H05B 45/10 (2020.01)] 11 Claims
OG exemplary drawing
 
1. A light source device comprising:
an electric power supply which outputs a voltage with a predetermined value in response to an output of an external power supply, and
at least one light source equipment, wherein
the at least one light source equipment comprises:
light sources which are series connected,
switches which are each connected in parallel with each of the light sources,
a light source drive circuit which supplies a current to a structure including the light sources and the switches in response to output electric power from the electric power supply, and
a switch control circuit which carries out on and off control of the switches,
the at least one light source equipment carries out light dimming control of the light sources by performing on and off control of the switches according to a light turned on duty ratio,
at least two of the light sources have a mutually different light turned on duty ratio, and
each of the light sources of the at least one light source equipment is sequentially light turned on from the one with a larger light turned on duty ratio to the one with a smaller light turned on duty ratio, and in addition, sequentially light turned off from the one with the smaller light turned on duty ratio to the one with the larger light turned on duty ratio.