Email format error
Email cannot be empty
Email already exists
6-20 characters(letters plus numbers only)
The password is inconsistent
Email format error
Email cannot be empty
Email does not exist
6-20 characters(letters plus numbers only)
The password is inconsistent
Special Lens
Our special effect camera lenses are designed to correct your vision while providing a superior look and feel.They have the latest fashion trends.
The invention of the concave lens and convex lens
The lens comes from Latin lentil, which comes from the Mediterranean region. In Japanese, this is another loanword, which was called "Tokyo (transparent mirror)" during World War II. Its origin can be traced back to the crystal ball or glass ball used as a fire-making tool in religious ceremonies or as an ornament in ancient civilizations. It is generally believed that the origin of the lens can be traced back to the ancient Roman philosopher Seneca 2000 years ago, who once said that "the crystal ball can enlarge characters".
The lens uses a principle called light "refraction": that is, light bends and changes the direction of travel. A thick spherical convex lens in the middle can converge light; The concave lens with a thick outer ring and hourglass shape can disperse light.
Use of concave lens and convex lens
Lenses have been evolving in two areas: glasses worn in daily life, and instrumental applications of lenses in microscopes, telescopes, and cameras. The first pair of glasses was put into practical use in the 13th century. It is only a simple magnifying glass using a convex lens. At first, it was called "the devil's tool". At the same time, glasses with two lenses were introduced, and myopia glasses with concave lenses were also invented in the 16th century.
Which of the microscope and telescope was invented first?
The correct answer is the microscope, which came out at the end of the 16th century. Later, the Englishman Hooke invented the compound microscope using two convex lenses (objective lens and eyepiece); Almost at the same time, the Dutch invented the single lens microscope. The telescope was invented by the Dutch Lippershey, who used a convex lens as the objective lens and a concave lens as the eyepiece. Galileo then improved this invention and applied it to astronomical observation. It was with this device that he discovered Saturn's rings. In addition, German astronomer Kepler designed a Kepler telescope with the convex lens as an objective and eyepiece.
Lens type
Concave lens and convex lens can be further subdivided into many different types, including a spherical lens with a circular surface, an aspheric lens with a curved surface but aspheric surface, a cylindrical lens with an arched back, an annular lens shaped like a doughnut, and Fresnel lens with washboard surface. On these lenses, light is refracted on the surface of the lens.
However, there are other types of lenses, including self-focusing lenses that produce optical effects with the help of gradient refractive index (the gradient refractive index is generated by the lens material, rather than through the refraction of the lens surface) and diffractive lenses that use the phenomenon of light wave dispersion. Self-focusing lenses are usually used in endoscopes, and diffractive lenses are usually used in CD and DVD players.
