What Is a Fiber-Optic Lens?

A lens is an optical element whose surface is part of a spherical surface made of transparent material. The lens is composed of several lenses. There are two types of plastic lens (glass) and glass lens (glass). Glass lenses are more expensive than plastic. Generally, the lens structure for a camera is: 1P, 2P, 1G1P, 1G2P, 2G2P, 4G, etc. The more lenses there are, the higher the cost. Therefore, a good quality camera should use a glass lens, which has a better imaging effect than a plastic lens, and plays an important role in astronomy, military, transportation, medicine, art and other fields.

[tòu jìng]

A lens is an optical element whose surface is part of a spherical surface made of transparent material. The lens is composed of several lenses. There are two types of plastic lens (glass) and glass lens (glass). Glass lenses are more expensive than plastic. Generally, the lens structure for a camera is: 1P, 2P, 1G1P, 1G2P, 2G2P, 4G, etc. The more lenses there are, the higher the cost. Therefore, a good quality camera should use a glass lens, which has a better imaging effect than a plastic lens, and plays an important role in astronomy, military, transportation, medicine, art and other fields.

Chinese name

lens

Types of

Optical element

Material

Transparent substance

Classification

plastic

Different structure

A convex lens is composed of a transparent lens body that is ground into a spherical surface on both sides, thin on both sides and thick in the middle.

The concave lens is composed of a transparent lens body that is ground into a concave spherical surface on both sides. The two sides are thick and the middle is thin.

Different effects on light

Convex lenses converge light

Concave lens diverges light

Different imaging properties

Convex lenses are refractive imaging

A concave lens is "the light passes through a concave lens and becomes an upright virtual image, while a convex lens is inverted

One. The lens is represented by the lens symbol (a line segment has two V-shaped marks at both ends)

Draw

The knowledge points of the junior high school applied physics knowledge contest about lenses and their application development are:

1. Three principles of lens imaging (three special rays): light parallel to the main optical axis, refracted by the lens and passed through the main focal point; light passing through the optical center is refracted by the lens and the direction is unchanged; passed through the main The light at the focal point is parallel to the main optical axis after being refracted by the lens.

2. Convex lens imaging formula: 1 / u (object distance) + 1 / v (image distance) = 1 / f (lens focal length). Understanding of the law of convex lens imaging:

a) One conclusion: the real is different, the false is the same. That is, the real image is always upside down on the opposite side, not only can be seen and can be taken over with a light screen; the virtual image is always upright on the same side, but can be seen but not taken over with a light screen.

b) Two points of demarcation: focus and 2x focal length. The focus is the boundary between the real image and the virtual image. When the object is located within the focal point of the convex lens, it becomes a virtual image; when the object is located outside the focal point of the convex lens, it becomes a real image. It can be abbreviated as: the focus is divided into reality inside and outside, inside and outside. The point at 2x focal length is the boundary point between the enlarged image and the reduced image. When the object is located between the 2x focal length and the focal point of the convex lens, it becomes a magnified real image; when the object is outside the 2x focal length of the convex lens, it becomes a reduced real image. Can be abbreviated as: 2 times the focal length points inside and outside divided into sizes, large inside and small outside.

Three changes: the size of the image and the change of the image distance: the object moves closer to the focus, the resulting image becomes larger, and at the same time the image distance becomes larger. Changes in the moving speed of the image: the object is located outside the point of 2 times the focal length (u> 2f), the object distance is greater than the image distance, and the real image is reduced by upside down. Between the focal points (f <u <2f), the object distance is smaller than the image distance, and it becomes an upside-down magnified real image, and the object moves faster than the image. The change in distance between object images: When the object is located at 2 times the focal length, and the image is at the other side, the object distance is the smallest, which is equal to 4 times the focal length. When the object is located outside the 2x focal length, the image is between the focal point on the other side and the 2x focal length, the object moves to the 2x focal length, and the distance between the object images becomes smaller; the object moves away from the 2x focal length. The distance between object images becomes larger. When the object is located within the 2x focal length (between the focal point and the point at the 2x focal length), and the imaging is outside the 2x focal length at the other side, the object moves to the point at the 2x focal length, and the distance between the object images becomes smaller; When the focus moves, the distance between object images becomes larger.

The objective lens is a final lens that focuses the electron beam onto the substrate.

Written records of lenses in Europe first appeared in ancient Greece, and glass burning (a convex lens that can gather sunlight to ignite) was mentioned in the dramatic clouds of Aristophanes (424 BC); The natural narrative of ancient Roman writer and scientist named Naturalis Historia , the old Pliny (23-79) also stated that the Roman Empire knew glass burning, and mentioned that the first possible correction of lenses Uses: Said to be an emerald used by Nero to watch fighting games. (Although the information available is not clear, it is presumed to be a concave lens that corrects myopia.) He and Pliny Jr. and Seneca the Younger (365 years ago) both describe glass filled with water. The ball has a zoom function. Arab mathematician Ibn Sahl (c.940c.1000) used known Snell's law to calculate the shape of a lens; Ibn al-Haitham (9651038) wrote the first theory of optics, describing How a lens images the retina of a human eye. The oldest artifact is a quartz lens excavated in Nineveh in Mesopotamia, appearing around 640 BC.

The book "Mozi" during the Warring States Period of China described the law of lens imaging. The second, fourth, and fifth articles in Mozi · Sutra and Mozi · Sutra said respectively the imaging laws of concave and convex lenses.

Recent excavations in the Viking port town of Fröjel, Gotland, Sweden, have shown that crystal lenses can be manufactured in the 11th to 12th centuries, and the quality can be compared with the aspheric lens of the 1950s. Viking lenses can gather sunlight to ignite the flame.

The spectacles were invented in Italy around 1280, before lenses were widely used. Nicholas Kusha is considered to be the first person to use a concave lens for the treatment of myopia in 1451.

The Abbe sine condition proposed by Ernst Abbe (1860) describes the conditions necessary for a lens or other optical system to produce an image as clear as the optical axis in an area away from the optical axis. He reformed the design of optical instruments, such as microscopes, and led the research and development of optical instruments.