Near-infrared absorbing composition, near-infrared absorbing film, and image sensor for solid-state imaging element

The patent introduces a specific solvent as an intermediary substance between the phosphonic acid copper complex and water. This solvent acts as a mediator that prevents direct interaction between the copper complex and water molecules, thereby maintaining dispersion stability while preserving near-infrared absorption performance. The solvent creates a protective environment that stabilizes the copper complex dispersion without compromising its optical properties.

The patent changes the chemical composition parameters of the dispersion system by selecting a solvent with specific properties (likely hydrophobic or low water solubility). This parameter change in the solvent composition prevents water from causing aggregation of the copper complex, thus improving dispersion stability while maintaining the near-infrared absorption capability of the copper complex.

The solvent serves as a protective intermediary that allows higher concentrations of copper complex to be dispersed without immediate aggregation. By mediating the interaction between copper complex molecules and the environment (heat and moisture), the solvent enables increased copper complex concentration for better near-infrared absorption while preventing the harmful aggregation effect.

The patent applies beforehand cushioning by pre-selecting a solvent that provides protective effects against heat and moisture-induced aggregation before these harmful factors act on the copper complex. The solvent creates a stable dispersion environment in advance, cushioning the copper complex from aggregation even at higher concentrations and under thermal or humid conditions.