US Patent No. 10,375,782

LED ARRANGEMENT AND LED DRIVING METHOD


Patent No. 10,375,782
Issue Date August 06, 2019
Title Led Arrangement And Led Driving Method
Inventorship Jie Fu, Shanghai (CN)
Shu Xu, Shanghai (CN)
Assignee SIGNIFY HOLDING B.V., Eindhoven (NL)

Claim of US Patent No. 10,375,782

1. A LED arrangement with a light output surface comprising an area of LED chips and an area between the LED chips, the LED arrangement comprising:a rectifier for rectifying a mains input;
a first group of LEDs distributed on the light output surface; and
a second group of LEDs distributed on the light output surface and in series with said first group of LEDs,
wherein said first group of LEDs is adapted to be kept turned on and the second group of LEDs is adapted to be bypassed when the rectified mains input is below a first threshold, and said first group of LEDs and the second group of LEDs are adapted to be kept turned on when the rectified mains input is above the first threshold such that the second group of LEDs are turned on for a second duration less than a first duration for turning on the first group of LEDs in each cycle of the rectified mains input and
a total light output density for the LEDs of the second group per unit area of the light output surface is greater than a total light output density for the LEDs of the first group per unit area of the light output surface, wherein a ratio of an area of LED chips of the second group of LEDs to a second area of the light output surface throughout which the second group of LEDs are distributed, is larger than a ratio of an area of LED chips of the first group of LEDs to a first area of the light output surface throughout which by the first group of LEDs are distributed,
wherein the total light output density for the LEDs of the first group per unit area of the light output surface and the total light output density for the LEDs of the second group per unit area of the light output surface are selected such that a total light output amount for the LEDs of the second group per unit area and per unit time is substantially equal to a total light output amount for the LEDs of the first group per unit area and per unit time.