to explain in detail―explain at great length―explain atlarge つぶさに説く - 斎藤和英大辞典
to explain in detail―explain atlarge 逐一説明する - 斎藤和英大辞典
to explain in detail―explain at great length―explain atlarge くわしく説明する - 斎藤和英大辞典
to explainat length―explain atlarge 詳しく説く、具さに説く - 斎藤和英大辞典
To explain in details, a light emitting layer is formed using the phosphorescent material having excellent light emission efficiency even when driving by a small current in at least one or more sub-pixel regions requiring large current drive when compared with other pixels in the organic electroluminescent element composed of sub-pixel regions of red, green, and blue colors. 詳細に説明すると、赤色と緑色と青色のサブ画素領域で構成される有機電界発光素子において、他の画素に比べて高電流駆動を必要とする少なくとも一つ以上のサブ画素領域に低電流駆動時でも発光効率が優れた燐光性物質を用いて発光層を形成する。 - 特許庁