noun
luminous flux
Physics term for the total amount of visible light emitted by a source per unit time, measured in lumens.
LEDの光束はルーメンで表される。
The luminous flux of an LED is expressed in lumens.
noun
beam of light; pencil of light
General term for a narrow, directed stream of light, such as a searchlight beam or a shaft of sunlight.
雲の切れ間から光束が差し込んだ。
A beam of light shone through a break in the clouds.