Optical lens assembly process and production processApexeloptic
An optical lens manufacturer is an indispensable part of the machine vision system, which directly affects the quality of imaging and the implementation and effect of the algorithm. Optical lenses can be divided into short focal lenses, medium focal lenses, and telephoto lenses from focal length. The field of view size is divided into wide Angle, standard, and telephoto lens; The structure is divided into fixed optical enclosure focal lens, manual optical enclosure focal lens, automatic optical enclosure focal lens, manual zoom lens, automatic zoom lens, automatic aperture electric zoom lens, electric three variables (aperture, focal length, focus variable) lens, etc.
Optics lens material general resin material or glass material, two kinds of material all have advantages and disadvantages, as easily shattered glass optics, optical performance is good, but due to the different production processes for some of the density of optical glass, casting not only affect their strength, and after grinding and polishing can affect its optical properties.
1. Assembly process of optical lens
Optical lens For such optical lenses, the process of assembling the lens is a process of adjusting aberrations (spherical aberration, coma, astigmatism, field curvature, distortion, and two chromatic aberrations).
The central point method makes use of transmitted light to generate diffraction spots on an aluminized glass plate and then adjusts them through the lens for microsystem observation. In THEORY, IF THE LENS HAS NO aberrATIONS, THE DIFFRACTION points SEEN IN THE EYEPIECE’s FIELD OF VIEW SHOULD BE air points plus a few thin rings, so the adjustment process of the transparent mirror is a real-time process of observing the shape of the diffraction point and changing the lens parameters.
The correspondence between the shape of the diffracted points and various aberrations is summarized as follows:
1. Spherical aberration: the ratio of spot brightness to the entire diffraction spot brightness is incorrect (theoretically 84%) or the diffraction ring is too thick; The general solution is to change the air gap by rotating the holder or adding spacers between the holder (software is required to simulate the mental sensitivity air gap of each and then decide where to change the lens position);
2. Coma: As its name suggests, it is a diffractive spot like the tail of a comet. The general solution is to adjust the coaxial. The gap between the middle two groups and the mirror body was about 0.1 ~ 0.2. It is also important to note that when the lens is first assembled, the difference is often obvious in a daze. It is generally necessary to adjust the coaxial, correct the coma, and then observe the coma to check for other kinds of aberrations.
3. Astigmatism: it is necessary to rotate the lens for observation, which can generally be improved by replacing the lens (the lens with difficult to adjust astigmatism is often because the surface shape of some lenses in the lens exceeds the tolerance.
2. What are the production processes of optical lenses?
Plastic lenses: The earliest plastic lenses were used during the war as telescopes, magnifying glasses, etc., mainly spherical lenses. Later, the optical plastic aspheric lens has gradually become the mainstream in the lens market. For example, most of the lenses used in myopia glasses are aspheric resin optical lenses. At present, plastic lenses are widely used in mobile phones, tablets, and other mobile devices. With the continuous improvement of the pixel of mobile phones, from the original 110,000 pixels to the current 20 million pixels and even higher, to improve the imaging quality, the lenses adopted by mainstream mobile phones are composed of more than 6 optical plastic lenses.
With the rapid development of plastic material technology, plastic lenses are now the main composition of mobile phone lenses. The plastic has good plasticity, low specific gravity, and is lightweight, which can effectively reduce the weight of the system, and the forming freedom is high, and the system mechanism components and optical components can be combined to simplify the system assembly procedure.
The shortcoming of plastic is low heat resistance of plastic, large coefficient of thermal expansion, deformation of optical components and influence of optical characteristics, poor scratch resistance, low mechanical strength, higher inhomogeneity, and easy shrinkage deformation. Plastic lenses are still the mainstream consumer electronics lenses due to their high requirements for low cost, capacity, thinness, and other aspects, and low demand for precision compared with professional optical instruments.
The plastic lens production process is mainly divided into injection molding and lens assembly two parts. Injection molding is referred to as injection molding, through the screw rod to stir the plastic into the injection machine heating cylinder plasticizing, so that it reaches the state of flow, the screw in the process of rotation gradually back, and the plastic is accumulated forward, the screw stops rotating, injection piston through the screw injection into the closed mold membrane cavity to form products.
Plastic aspheric lens molding belongs to the white object molding in injection molding, which is mainly used in the assembly of mobile phone lenses, digital lenses, zoom lenses, and vehicle leases. The lens set is the assembly of accessories immediately. Several lenses, diaphragms, pressure rings, and other accessories are assembled and synthesized into the finished lens according to the requirements of the assembly operation standard book. After assembly, the whole process of the lens assembly is completed through the stray light test, module test, and finished product appearance inspection.
Glass lens: Glass lens is composed of glass lenses. It is mainly used in high-end photography equipment with high imaging quality requirements, such as SLR cameras. The number of lenses can be as many as ten pieces. The traditional glass optical lens is made by manual grinding method, that is, the glass material is melted into the lens coarse embryo at a high temperature, and then the glass spherical lens is made by grinding, grinding, cleaning, coating, and other processes.