Annular Optical Spacer with Grooved Inner Surface

The optical spacer features a black coating layer applied selectively to its inner surface, creating a local quality difference. The black coating is positioned specifically where light reflection needs to be suppressed (inner surface facing the lens elements), while other surfaces may remain different. This localized application resolves the contradiction by targeting the harmful reflection issue without complicating the overall manufacturing process.

The patent applies a black coating to the optical spacer's inner surface, utilizing color change as a functional property. The black color has low reflectivity and high light absorption characteristics, which directly addresses the problem of unexpected light reflection. This color change approach maintains manufacturing simplicity while effectively suppressing harmful light reflection.

The black coating is applied specifically to the inner surface of the optical spacer that faces the lens elements, creating a localized quality improvement. This targeted approach ensures that the surface with the most critical light interaction receives the enhanced light-absorbing property, thereby reliably suppressing unexpected lights and improving image quality without requiring treatment of the entire spacer surface.

The optical spacer combines the base material (transparent optical plastic or glass) with a black coating layer, creating a composite structure. The base material maintains optical transparency where needed, while the black coating layer provides light absorption and reflection suppression. This composite approach achieves reliable image quality improvement by combining complementary material properties.

The patent utilizes a black coating applied to the optical spacer surface, leveraging the inherent light-absorbing properties of black color. This approach is relatively simple compared to complex surface treatments like atomization, as it can be applied through standard coating processes. The color change method effectively reduces reflectivity and suppresses unexpected lights without significantly increasing manufacturing complexity.

The patent changes the surface optical parameter (reflectivity) by applying a black coating with different optical properties than the base material. This parameter change approach is simpler than complex surface treatments because it relies on the fundamental optical property of black materials (low reflectivity, high absorption) rather than requiring sophisticated surface structuring or atomization processes.