Sensing Device Light Blocking Layer Thickness

The patent merges the light blocking function with existing structural layers, specifically integrating the light blocking capability into the electrode layers and insulating layers that are already part of the device architecture. By combining multiple functions (electrode function, insulation function, and light blocking function) into unified layers, the patent achieves improved measurement precision through effective stray light blocking without adding separate light blocking layers that would increase device thickness.

The patent implements multi-functionality in the electrode and insulating layers, which simultaneously serve as electrical components and optical components for blocking stray light. These layers perform multiple roles: providing electrical connectivity, providing insulation, and blocking reflected light from reaching the light receiving element. This multi-functional design improves measurement precision while avoiding additional thickness from dedicated light blocking layers.

The patent introduces light blocking layers as intermediary elements positioned between the light emitting unit and the light receiving element. These intermediary layers strategically block direct light paths from the light source to the receiver while permitting reflected light from the subject to reach the receiver. This mediator approach resolves the contradiction by enabling close positioning of the light emitting unit for improved precision while preventing direct light contamination through the blocking layers.

The patent converts the potentially harmful direct light that could contaminate the receiver into a beneficial configuration by using light blocking layers to selectively prevent direct light paths while maintaining reflected light paths. The structure is designed so that the light blocking layers, which might seem to obstruct light, actually improve precision by eliminating the harmful direct light component while preserving the useful reflected light component that carries the measurement information.