What does Liang Wen's 2835 patch mean and where is it used? Seeking introduction

2835 lamp bead is a medium-power SMD ultra-bright LED, with 0.2W and 0.5w. Because its size is 2.8 (width) ×3.5 (length) ×0.8 (thickness) mm, it is named 2835 lamp bead according to the size naming method of SMD LED lamp bead. Generally suitable for medical lamps in medical and other industries.