The pressure cementing process of optical components is one of the key techniques used in bonding optical elements—particularly in the production of bifocal lenses and other optical parts employed in medical and scientific optical devices. The primary aim of this method is to minimize optical aberrations, especially spherical and chromatic aberrations, by bonding two or more lenses made of different optical materials.
To ensure the success of the process, specific operational conditions must be met, including:
• High surface smoothness of the optical interfaces
• Perfect matching of the lens curvature centers, ensuring no air gaps exist between the bonded surfaces
• A cleanroom environment, free of dust and airborne particles, with a cleanliness standard of 3 particles per cm²
• The number of Newton’s rings between spherical surfaces should be minimized (target value: N = 0.5)
• High precision in surface flatness, with parallelism accurate to 2–3 seconds of arc
• Temperature control in the cleanroom must be maintained between 22–24°C to prevent delamination during or after the bonding process
Process Overview
Achieving effective lens cementing requires a high degree of skill and attention to detail. Prior to bonding, the lenses must be thoroughly cleaned using appropriate chemical agents to remove all volatile substances and particulates.
The actual cementing is performed under very high pressure—up to 1 bar—to eliminate unwanted residues and ensure strong adhesion. Once bonded, the lenses can only be separated through the application of controlled heat, highlighting the strength and permanence of the pressure bond.
Following bonding, the lenses must undergo rigorous optical inspection using precision instruments such as:
• Interferometers
• Collimators
These tools verify that the resulting lens assembly is free of optical defects and aberrations. This technique is especially crucial in the fabrication of high-quality bifocal lenses and optical components used in medical imaging devices.
Conclusion
Pressure cementing, also known as optical cementing, is regarded as the most accurate and reliable method for producing bifocal medical lenses and high-performance optical systems. When executed under precise conditions and with skilled personnel, it ensures exceptional optical clarity, structural integrity, and long-term durability.