An optical sensing system is disclosed. The optical sensing system includes a printed circuit board (PCB), a supporter and an optical sensor. The PCB includes a top surface, a bottom surface and a through cavity, wherein the through cavity extends downwardly from the top surface to the bottom surface. The supporter has a top surface and a bottom surface. The optical sensor is bonded and coupled to the top surface of the supporter, wherein the optical sensor includes a primary optic structure. Wherein the supporter is flipped over and bonded to the PCB with the top surface facing the through cavity, so that the optical sensor is coupled to the PCB and at least partially extends to the through cavity. Associated electronic devices are also disclosed.本發明實施例揭示一種光學感測系統。該光學感測系統包含一印刷電路板(PCB)、一支撐件及一光學感測器。該PCB包含一頂表面、一底表面及一貫穿腔，其中該貫穿腔自該頂表面向下延伸至該底表面。該支撐件具有一頂表面及一底表面。該光學感測器經接合且耦合至該支撐件之該頂表面，其中該光學感測器包含一主要光學結構。其中該支撐件經翻轉且接合至該PCB，其中該頂表面面向該貫穿腔，使得該光學感測器耦合至該PCB且至少部分延伸至該貫穿腔。本發明實施例亦揭示相關聯電子裝置。
