Optical filter lens can be widely used in security, car wear, digital camera, laser, optical instruments and other fields. With the continuous development of the market, lens technology is also more and more widely used.
Lens are made according to the law of refraction of light. Lens are optical elements made of transparent materials such as glass, crystal, etc. A lens is a refractor whose refractive surface is a transparent body of two spheres (a part of the sphere) or a plane of one sphere (a part of the sphere). It has both real and imaginary images.
Convex lens: thick middle, thin edge, double convex, flat convex, concave convex three kinds;
Concave lens: thin middle, thick edge, with double concave, flat concave, convex concave three kinds.
Thin lens is a kind of lens whose thickness of the central part is larger than the curvature radius of its two sides. In the early days, the camera only had a convex lens, so it was called a "single lens". With the development of science and technology, modern lenses have a number of convex and concave lenses of different forms and functions to form a convergent lens, which is called "compound lens". The concave lens in the compound lens corrects various aberrations.
A lens is an optical element made of transparent material with a spherical surface. The lens is composed of several lenses. There are plastic lenses and glass lenses. Glass lenses are more expensive than plastic lenses. Usually, the lens structure used in the camera is: 1P, 2P, 1G1P, 1G2P, 2G2P, 4G, etc. The more lenses, the higher the cost. Therefore, a good quality camera should use glass lens, its image effect is better than plastic lens, which plays an important role in astronomy, military, transportation, medicine, art and other fields.
Optical glass has high transparency, purity, colorless, uniform texture, and good refractive power, so it is the main raw material for lens production. Optical glasses with different chemical composition and refractive index are:
1. Flintstone Glass - Lead oxide is added to the glass composition to increase the refractive index (1.8804)
2. Corona glass - Made by adding sodium oxide and calcium oxide to the glass composition to reduce its refractive index (barium corona glass refractive index is 1.7055)
3. Lanthanum Corona Glass - for the variety found, it has the excellent characteristics of high refractive index and low dispersion, which provides conditions for creating large-caliber high-level lens.
Lens are the basic optical elements that constitute the optical system of a microscope. Objects, eyeglasses and concentrators are composed of single and multiple lenses. According to their different shapes, they can be divided into convex lens (positive lens) and concave lens (negative lens).
When a beam of light parallel to the main optical axis intersects at a point after passing through a convex lens, this point is called the "focus" and the plane through which the focus is perpendicular to the optical axis is called the "focal plane". There are two focal points in the object space, which are called "object focus". The focal plane in this place is called "object focus plane". On the contrary, the focal plane in the image space is called "image focus". The focal plane in this place is called "image focus plane".
When light passes through a concave lens, it becomes a positive virtual image, while a convex lens becomes an inverted real image. Real images can be displayed on the screen, but virtual images can't.