紫外光

• 此(this; here)PHONETIC
• 糸(silk thread; silk)RADICAL

A silk thread dyed in this distinctive purple color is the noble color of the imperial palace.

• 夕(evening; crescent moon (pictographic))RADICAL
• 卜(divination; fortune-telling)PHONETIC

Evening outside divining fortunes under the moon — that's an external affair.

• ⺌(small light radiating upward)ASSOCIATIVE
• 兀(standing person; upright person)ASSOCIATIVE

Light shining down from above a person standing upright creates the image of 光, meaning light.