Compound Focusing Lens

Composite focusing lenses typically include different types of lenses (such as convex lenses, concave lenses), lens groups, and may also incorporate some special optical materials or coatings. These components are arranged in a specific order and spacing, and work together to control the propagation and focusing of light. For example, a simple composite focusing lens may be composed of a biconvex lens and a plano concave lens tightly bonded together, where the biconvex lens is used to initially converge the light, and the plano concave lens is used to correct the aberrations and chromatic aberration that the biconvex lens may produce.

working principle
Light convergence and focusing: Each component in a composite focusing lens refracts light. Taking a composite focusing lens containing convex and concave lenses as an example, when light enters the convex lens section, according to the imaging principle of the convex lens, the light will refract towards the central axis direction of the lens and begin to converge. Then, the light enters the concave lens section, which causes the light to diverge. However, since the entire composite focusing lens is designed, the diverging effect of the concave lens is to fine tune the converging light produced by the convex lens. This fine-tuning can precisely control the final focus position of the light, allowing the light to form a clear focal point at the desired position.
Aberration and chromatic aberration correction: A single lens often produces aberrations (such as spherical aberration, coma, astigmatism, etc.) and chromatic aberration during the imaging process. Composite focusing lenses correct these issues by properly combining different optical elements. Lenses of different materials and shapes refract light of different wavelengths differently. By selecting lenses made of materials with complementary dispersion characteristics and combining them in a composite focusing lens, chromatic aberration can be effectively reduced. For aberration correction, for example, using a combination of non spherical lenses and spherical lenses, or a combination of lenses with different curvature radii, to compensate for aberrations after the light passes through multiple refractive elements. In the design of optical microscope objectives, composite focusing lenses can greatly improve the clarity and accuracy of imaging, reduce phenomena such as edge blurring and color distortion.
Application scenarios
In the field of laser processing, composite focusing lenses are key optical components in applications such as laser cutting, laser welding, and laser marking. It can focus the laser beam to a very small spot size, thereby achieving high energy density processing. By precisely controlling the focal position, high-precision machining operations can be carried out on different materials such as metal, plastic, ceramics, etc., and the focal position can be flexibly adjusted according to the thickness of the material and machining requirements.
In the field of optical imaging, it is widely used in optical imaging equipment such as camera lenses, microscope objectives, and telescope objectives. In camera lenses, composite focusing lenses can provide high-quality imaging effects and adapt to different shooting scenes and distances. In microscopes and telescopes, it can improve resolution, allowing observers to see micro or macro object details more clearly.
In the field of optical communication, composite focusing lenses are used to effectively couple laser signals into or out of optical fibers in fiber optic communication systems. By precise focusing and alignment, signal loss can be minimized to the greatest extent possible, improving communication efficiency and quality.
Meanwhile, in some optical communication devices such as optical switches and wavelength division multiplexers, composite focusing lenses also play an important role in controlling the propagation and distribution of optical signals.