optical lens search
The optical lens was a very important component in the machine vision system. It was directly related to the quality of the image and also affected the implementation and effect of the algorithm. In terms of focal length, it could be divided into short focal length lens, medium focal length lens, and telephoto lens. According to the size of the field of view, there were wide-angle lens, standard lens, and telephoto lens. In terms of structure, it could be divided into fixed-aperture fixed-focal length lens, manual fixed-aperture fixed-focal length lens, automatic fixed-aperture fixed-focal length lens, manual zoom lens, automatic zoom lens, automatic aperture electric zoom lens, and electric three-variable (aperture, focal length, and focus can be changed) lens. In the security field, large foreign manufacturers (such as Canon, Nikon, and other Japanese manufacturers) had monopolized the source of lenses for a long time. However, in recent years, domestic lenses (Sunny Optics, Yutong Optics, United Optoelectronics, Fuguang, etc.) have risen. In the middle and low-end market of the security field, domestic companies have occupied an absolute proportion. However, foreign companies (such as Tenglong, Fujineng/Fujinlong, etc.) still have a certain degree of competitiveness in the high-end market. For example, in 1978, Fuji was able to produce the first HD lens and had maintained a leading position in the field of high-end lenses. In terms of global market revenue, the combined revenue of the optical lens industry in the video surveillance, smartphone, and car camera fields in 2017 was nearly 6 billion US dollars. It continued to grow between 2018 and 2019 and was expected to exceed 7 billion US dollars in 2021. In addition, Jiangxi Lianyi Optics Co., Ltd. obtained a patent called "optical lens" on October 19,2024, with the authorization announcement number of CC118348660B. There was also an Atlas of Aerial Photographic Optic Lenses "Russa", which contained the optical structure drawings and main aberrations of almost all the aerial photographic optical lenses "Russar" designed by the Russian scholar Professor Rusinov. The attached table also listed the design parameters (lens curvature radius, optical materials, etc.). It was suitable for optical system design and calculation experts, engineering technicians, university teachers, graduate students, and aerial photography optical enthusiasts. Read more exciting novels for free
The hood of an optical lens
The hood was a device installed at the front of the camera lens, digital camera, and video camera. It was an important part of the lens optical system. Its main uses included: 1. ** Suppression of stray light **: avoid glare and improve image clarity and color reproduction. In different light positions such as backlighting, side backlighting, forward lighting, side lighting, lighting photography or night photography, it can prevent non-imaging light, surrounding scattered light or interference light from entering the lens, avoid fog and halo phenomena, and improve the color saturation and clarity of the picture. 2. ** Protect the lens **: When the lens is accidentally dropped, it can help reduce the damage caused by the fall; it can prevent fingers from accidentally touching the surface of the lens; it can also block the sand, rain, snow, etc. to a certain extent to prevent other things from directly touching the surface of the lens. In terms of usage, the hood in front of all the lenses had been carefully calculated by the manufacturer to help improve the quality of the shot. If the lens was equipped with a crystallizer, although the crystallizer and the hood had no similarities, the hood still needed to be installed. When rotating the crystallizer, the hood could be turned upside down and buckled on the lens, or temporarily removed and placed in the camera bag. It was not necessary to buy the original hood. Buying a hood that matched the lens 'caliber and angle of view could play its role. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The optical parameters on the lens
The following is some common optical parameters on the lens: 1. ** effective focal length (EFL)**: The distance from the center of the lens to the focal point. It could be divided into image focal length (the distance between the main surface of the image and the focal point of the image) and object focal length (the distance between the main surface of the object and the focal point of the object). If the focal length is too short, it will cause the field of view to be too large, causing distortion, difficulty in controlling the angle of the chief ray, low contrast, serious lens bending, difficulty in correcting the phase difference, and other problems. If the focal length is too long, the lens will be too long, which is not conducive to the miniaturized system. Moreover, the field of view is too small to meet the user's needs (FoV>60°). 2. ** Total length of lens (TL)**: It is divided into optical length (the distance between the first surface of the lens and the image surface) and mechanism length (the distance between the end of the lens barrel and the image surface). 3. ** Back focal length (BTL)**: The distance from the last side of the lens in the optical system to the image plane. 4. ** Front focal length (FFL)**: The distance from the first surface of the lens to the object surface in the optical system must be distinguished from the back focal length of the mechanism. 5. ** Mechanical back focal length (FTL/FFL)**: The distance from the last mechanical surface of the lens group to the image surface. 6. ** Field of View (FoV)**: The largest field of view that the camera can capture. It can be divided into diagonal field of view (FoV-D), horizontal field of view (FoV-H), and vertical field of view (FoV-V). The diagonal field of view is the largest, followed by the horizontal field of view, and the vertical field of view is the smallest. The so-called field of view refers to the diagonal field of view of the digital camera module. The size of the field of view was related to the focal length. Generally, the larger the field of view, the shorter the focal length. 7. ** Joules (F/NO.)**: It was the ratio of the effective focal length to the diameter of the pupil, which was used to determine the brightness of the lens. Under the premise of ensuring the same aperture, the shorter the focal length, the smaller the relative aperture should be. In general, the smaller the F/#, the larger the aperture. 8. Distortion: It is the off-axis phase difference. It is the height difference between the intersection point of the off-axis point and the main ray on the image plane and the ideal (paraxial-like) image plane. It is a function of the field of view and has nothing to do with the aperture. Distortion was divided into TV distortion and optical distortion. TV distortion was further divided into pillow type and cylinder type. Distortion is the image quality that users can easily feel. Different application scenarios have different requirements for distortion. For example, Optical-Distortion <3% is not easy to detect by the human eye, and the objective lens generally requires Optical-Distortion <2%. 9. ** relative illumination (Ri)**: The ratio of the central illumination to the peripheral illumination. If the contrast was too low, the center of the image would be bright and the surroundings would be dark (vignette phenomenon, commonly known as dark corners), which would also cause color distortion. The Ri is directly proportional to COS4 (semi-fov). Different semi-fov correspond to different theoretical values of the Ri. When the Ri<50%, the human eye can distinguish it. In serious cases, the four corners of the picture will be completely black. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Bengbu optical lens
Bengbu Ciyt Changtian Optoelectronic Technology Co., Ltd. has optical lens blank and optical lens project. In addition, Bengbu had a certain development in optics-related industries. For example, there were companies involved in optical lens coating technology. For example, Bengbu Ciyt Optoelectronic Technology Co., Ltd. developed an optical lens coating device that could coat optical lenses of different sizes and automatically flip them over to coat them on both sides. There was also a device for processing optical lenses that automatically controlled the amount of polishing liquid squeezed out. There were also companies that planned to invest in the construction of optical module industrial base projects. For example, Laitong Optoelectronics Co., Ltd. planned to invest 1.36 billion yuan in the construction of upstream and downstream industrial bases including optical lenses. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Beijing optical lens
There were many optical lens related companies in Beijing, such as Bo Li (Beijing) Optoelectronic Technology Co., Ltd., Xi Bi Xi Optics (Beijing) Co., Ltd., Beijing Goppu Optoelectronic Technology Co., Ltd., etc. In terms of the optical lens industry, there were optical, optical mirrors, lenses, light sources, photoelectricity, lasers, 3D cameras, artificial intelligence, instruments/meters, photolithographic machines, etc. The proportion of optical, optical mirrors, and lenses was 7.1%, and the proportion of light sources, photoelectricity, and lasers was 4.8%(data for reference only). <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Mobile phone external lens optical lens
The external lens of the mobile phone had many types and functions. For example, there was a PVP optical lens for mobile phone lenses, which was a three-in-one wide-angle + fish-eye + macro lens. This lens was a high-quality optical lens with high clarity, large angle, low distortion, and no dark angle. Its standard set included a 0.67X super wide-angle lens, a 180-degree fish-eye + 15 macro lens (the wide-angle and macro lenses could be freely disassembled), a universal mobile phone clip, a micro-fine cloth fluffy bag, and a plastic carton packaging. There were six colors to choose from. There were also some other mobile phone lenses, such as the Momis X-lens 2-in-1 elite mobile phone lens set made of aluminum alloy and optical lens for 120° wide angle +15X macro. These optical lenses helped to improve the imaging effect of the external lens of the mobile phone and meet the needs of different users for photography, such as expanding the shooting range and clearly showing small objects in macro shooting. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The technical parameters of the optical lens
The main technical parameters of the optical lens were as follows: 1. ** effective focal length (EFL)**: The distance from the center of the lens to the focal point. It was further divided into image focal length (the distance between the main surface of the image and the focal point of the image) and object focal length (the distance between the main surface of the object and the focal point of the object). If the focal length is too short, the field of view will be too large, resulting in distortion, difficulty in controlling the main ray angle, low contrast, serious lens bending, difficulty in correcting the phase difference, and other problems, which is not conducive to the design; if the focal length is too long, the lens will be too long, which is not conducive to the miniaturized system. If the field of view is too small, it is difficult to meet the user's needs (FoV>60°). 2. ** Total length of lens (TL)**: It is divided into optical length (the distance between the first surface of the lens and the image surface) and mechanism length (the distance between the end of the lens barrel and the image surface). 3. ** Back focal length (BTL)**: The distance from the last side of the lens in the optical system to the image plane. 4. ** Front focal length (FFL)**: The distance from the first surface of the lens to the object surface in the optical system must be distinguished from the back focal length of the mechanism. 5. ** Mechanical back focal length (FTL/FFL)**: The distance from the last mechanical surface of the lens group to the image surface. 6. ** Field of view (FoV)**: refers to the largest field of view that the lens can capture. It can be divided into diagonal field of view (FoV-D), horizontal field of view (FoV-H), and vertical field of view (FoV-V). The diagonal field of view is the largest, followed by the horizontal field of view, and the vertical field of view is the smallest. The so-called field of view usually refers to the diagonal field of view of the digital camera module. 7. ** Joules (F/NO.)**: It is the ratio of the effective focal length to the diameter of the entrance pupil, which is used to determine the brightness of the lens. Under the premise of ensuring the same aperture, the shorter the focal length, the smaller the relative aperture should be. In general, the smaller the F/#, the larger the aperture. 8. ** Distortion **: It is the off-axis phase difference. It is the aberrations of the off-axis thin beam. It is the height difference between the intersection point of the off-axis point and the main ray on the image plane and the ideal (near axis) image plane. It is a function of the field of view and has nothing to do with the aperture. The primary distortion changes with the cubic power of the field of view (image height), and the percentage distortion increases with the square of the image height. The distortion varies with different fields of view, and the distortion changes are non-linear. It is only the distortion of the image and does not affect the clarity of the image. Distortion is divided into TV distortion and optical distortion. TV distortion is further divided into pillow type and cylinder type. Different application scenarios have different requirements for distortion. For example, Optical-Distortion <3% is not easy to detect by the human eye, and Optical-Distortion <2% is the distortion requirement of the photographic objective lens. 9. ** relative illumination (Ri)**: The ratio of the central illumination to the peripheral illumination. If the contrast was too low, the center of the image would be bright and the surroundings would be dark (vignette phenomenon, commonly known as dark corners), which would also cause color distortion. The Ri is directly proportional to COS4 (semi-fov). Different semi-fov values correspond to different theoretical values of the Ri. When the Ri<50%, the human eye can distinguish it. In serious cases, the four corners of the picture will be completely black. 10. ** resolution **: It can be defined as the number of pairs of black and white stripes that can be distinguished in millimeters when the lens is used to observe the black-and-white grid pattern. When selecting a lens, the lens resolution is usually required to be slightly higher than the resolution of the picture element. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Classic lens optical structure
The following are the optical structures of some classic lenses: 1. Single-piece lens (one set, one piece): It was first invented by the Englishman Wollaston in 1812. It had a maximum aperture of F16 and was called a crescent-shaped landscape lens. Its structure could not change the aperture. It was mostly used in early simple box-type cameras (mainly for artists to draw pictures). This structure was similar to the structure of the human eye, but because the camera lens only had one lens, the image would have problems such as spherical aberrations, color aberrations, and coma. Lenses with this structure were commonly seen in presbyopic glasses, but strictly speaking, presbyopic glasses could not be called lenses. 2. **1 set of 2 lens structure **: invented by the Frenchman Chevalier in 1821. It was an achromatic lens with a maximum aperture of F14. It was also a lens with a non-changeable aperture. It glued the concave lens and the concave lens together to eliminate some of the color aberrations. In 1839, the Kilux camera invented by Daguerre used this kind of lens. 3. ** Petzval structure (3 sets of 4 pieces)**: In 1840, the Austrian mathematician Professor Petzval used mathematical methods to design a portrait lens with a maximum aperture of F3.7. This structure of the lens is still popular today. 4. ** Double Gauss structure **: It appeared during World War II. 5. [Heavenly Sai structure: 100 years of history.] <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
optical magnification of telephoto lens
In a 35mm film, the 50mm lens had a fixed magnification of one, which was called the header. However, there was no fixed and uniform value for the optical magnification of a telephoto lens. Different telephoto lenses have different optical magnifying powers. For example, mobile phone telephoto lenses may have optical magnifying powers such as 3X, 5X, and 10X, while camera telephoto lenses are commonly seen in different specifications such as 70 - 200mm. The number here represents the focal length of the lens, which is related to the optical magnifying power, but not directly equal to the optical magnifying power. Moreover, the phone's telephoto lens had a 6x magnifying power. The focal length of the lens mentioned in sports photography, such as 400mm, 600mm and other telephoto lenses, also reflected the difference in focal length of different telephoto lenses, which also reflected different optical magnifying abilities. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What is the optical distortion of the lens?
The distortion of ordinary industrial lenses was generally 1% - 2%. The distortion of the dual monocentric lenses of the MTOS was generally less than 0.1%. The distortion rate of the MLM series of monocentric lenses and the MCHR series of macro lenses was 0.0x% - 0.00x%. However, the optical distortion specifications of different types of lenses varied, and the specific values depended on factors such as the design, use, and performance of the lens. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Coaxial-optical lens manufacturer
Coaxial-optical lens manufacturers include Ningbo-Jiangdong Zhang Tianan optical instrument business department, Shenzhen-Dehong Vision Technology Co., Ltd., Shanghai-Puhe Optoelectronic Technology Co., Ltd., etc. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>