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Aspherical lenses usually refer to an optical lens that is commonly used to correct spherical aberration in the optical field. So what is spherical aberration? What ability does an aspherical lens have to eliminate spherical aberration to the greatest extent? Let’s learn about them one by one and discover the secrets.
Aspheric lens production process
In the field of optical manufacturing, manufacturing aspherical lenses requires very precise and complex techniques to achieve the uneven curvature of their surface features. Therefore, the manufacture of these lenses requires a more complex manufacturing process than ordinary spherical lenses to ensure that the surface of the lens accurately conforms to the required aspherical profile, so that optical aberrations such as spherical aberration can be corrected. Below we give some reference data and briefly introduce some important parameters in the production of aspherical mirrors. Specific manufacturing data needs to be based on your specific requirements.
| Parameter | Typical Values |
|---|---|
| Diameter(mm) | 10-300 |
| Diameter Tolerance(mm) | ±0.05-±0.2 |
| Peak Slope Error(mrad) | <5 |
| Aspheric Map Error(μm) | <1 |
| Vertex Radius(mm) | 10-2000 |
| Center Thickness Tolerance(mm) | ±0.05-±0.2 |
| Surface Accuracy(WAVES@632.8nm) | λ/10-λ/20 |
| Surface Roughness(nm) | <3-<10 |
Diameter and diameter tolerance define the overall size and allowable variance of a lens, which is critical for assembly into an optical system.
Peak slope error and aspheric map error quantify the deviation of the lens surface from the ideal aspheric shape, affecting the lens’s ability to effectively correct aberrations.
Apex radius represents the curvature of a lens at its most curved point, which is a key factor in determining its focusing characteristics.
Center thickness tolerance is critical to optical performance and affects the mechanical stability of the lens and its optical path length.
Surface accuracy measures the conformity of a lens surface to an ideal shape (expressed in wavelengths of light), which is critical to minimizing optical aberrations.
Surface roughness affects the scattering of light, with lower values indicating a smoother surface, thereby enhancing image clarity and reducing light loss.
Design and Prototyping
The manufacturing process of aspherical lenses starts with optical design. Our excellent optical engineers use advanced software to model and design aspherical lenses according to our customers’ special application requirements. This stage involves defining the aspherical equation of the lens, which determines its curvature.
The general equation of aspheric surfaces is fundamental in the design process and is given by:
z is the sagitta, the distance from the mirror vertex to the surface along the symmetry axis, r is the radial distance from the optical axis, c is the curvature at the vertex (1/R, where R is the radius of curvature at the vertex), k is the conic constant ( Determine the type of conic section represented by the mirror segment: k=−1 represents a parabola, k<−1 represents a hyperbola, 0>k>−1, A, B, C, D,… are used to define aspherical and simple conical shapes The coefficient of the higher-order term of the deviation.
The equations we provide form the backbone of the entire design process, essentially providing a mathematical representation of complex surfaces that significantly improve optical performance by minimizing aberrations. However, the specific design still needs to be modified according to the actual situation.