What are the common aberrations in machine vision lenses?

Aberrations are crucial factors affecting image quality, and the imaging quality of different machine vision lenses varies. Even when using the same type of industrial lens, factors such as precision in processing, lens structure, and material differences lead to variations in image quality. Consequently, the prices of industrial lenses vary from hundreds to tens of thousands of yuan.

When selecting industrial lenses, the primary consideration is aberrations, as they significantly impact imaging quality. Here are six common aberrations in machine vision lenses:

1. Spherical Aberration:

    Caused when a monochromatic conical beam is emitted from a point on the optical axis. After refraction through the optical system, if rays of the original beam with different aperture angles do not converge at the same position on the optical axis, a scattered light spot (commonly known as a blur circle) is formed on the ideal image plane along the optical axis. This imaging error is known as spherical aberration.

2. Coma:

    Originating from a monochromatic conical beam emitted from a point outside the optical axis. After refraction through the optical system, if it doesn't form a clear point on the ideal image plane and instead forms a comet-shaped light spot with a bright tail, it is called coma.

3. Astigmatism:

    Arises when a monochromatic conical beam is emitted from a point outside the optical axis at an oblique angle. After refraction through the optical system, it fails to form a clear image point and instead forms a scattered light spot. This imaging error is referred to as astigmatism.

4. Field Curvature:

   Occurs when a clear image of a planar object perpendicular to the optical axis is formed by the optical system. If the image does not lie within a plane perpendicular to the optical axis but on a curved surface symmetrically with respect to the optical axis, where the best image plane is a curved surface, it is termed field curvature. When focusing on the central part of the image, the peripheral areas appear blurry, and vice versa.

5. Distortion:

   Straight lines outside the optical axis within the object plane become curved after imaging through the optical system, resulting in distortion. Distortion aberration only affects the geometric shape of the image without affecting its clarity. This is the fundamental difference between distortion and spherical aberration, coma, astigmatism, and field curvature.

6. Chromatic Aberration:

   Occurs when a white object emits a bundle of white light towards the optical system. After refraction through the optical system, different colors of light fail to converge at a single point, forming a colored image spot, known as chromatic aberration. The cause is the varying refractive indices of the same optical glass for different wavelengths, with shorter wavelengths having higher refractive indices and longer wavelengths having lower refractive indices.

Xinxiwang specializes in the professional sales of machine vision systems, machine vision lighting, machine vision cameras, machine vision lenses, machine vision software, and other related products. Feel free to call us at 028-62705808.