What Are Common Materials For A Camera Lens

Digital imaging lenses are oft made of multiple lens elements to achieve the required specifications. How are those lens elements made in mass production? The respond to this question depends on the type of element chosen by the lens pattern engineer. Three types of lens elements are commonly used today. They are polished glass elements, molded plastic elements, and molded glass elements. Each blazon of element has its ain unique procedure steps and capabilities. A good understanding of the manufacturing process for each type can help to ensure that the lens pattern can exist successfully realized in practice.

Polished glass: This type of element is the best known and well-nigh common. The elements used by Galileo in his refractive telescope were made by this method. Though the basic idea of how to brand a polished glass element hasn't changed for centuries lot of progress has been made in the speed and precision of the manufacturing procedure. The steps in making a polished drinking glass element involves starting time making a blank from the chosen glass material type. Today there are hundreds of unlike types of drinking glass materials bachelor from several major optical glass manufacturers. Each glass type has different optical, mechanical, chemical, and thermal backdrop. It is the chore of the lens designer to cull the advisable glass material based on the stop application requirement. Once the glass blazon is chosen there are two ways to make a blank. For pocket-size quantity needs i can CNC machine a rough oversized shape resembling the last element. For higher volume production the drinking glass manufacturer can provide a molded bare having the approximate shape. In either case, the glass blank is then mounted on a grinding machine where a grinding cycle forms the ii surfaces of the elements to the required radii. After grinding where the surface radii are approximately formed a final polishing step is used to make each surface shine and shining. An optional optical coating is and then applied to each surface using an optical coater. The final step is to center the element on a centering machine and a precise bore is achieved past grinding downwards the backlog material. This procedure has been perfected over many centuries. The capabilities of this process are amazing. Element sizes ranging from small endoscopic lenses to large telescope mirrors are made using this basic process. However, because of the grinding and polishing processes only flat or spherical shapes tin can be made. If a lens pattern calls for an aspherical element in either drinking glass or plastic we would demand to use the following processes.
Molded plastic: Optical plastic materials offering very attractive properties for certain applications such as mobile imaging cameras. The predominant manufacturing process of plastic is injection molding. The bones process of injection molding is to melt the plastic resin so information technology can flow freely. This fluid is injected under loftier force per unit area to a precision mold cavity. The shape of the mold cavity determines the shape of the lens chemical element. Once the mold cavity is filled it is cooled to let the textile to harden. Once the fabric is solid again information technology is removed from the mold. Depending on the size of the element the wheel time tin can exist every bit short as a infinitesimal. Multi-crenel molds are oftentimes used to achieve high-book production. These characteristics of injection molding allow for the economic production of lens elements with a high degree of precision. A major technical do good of injection molding is that almost whatever shape tin be molded equally long as the mold cavity tin can be fabricated in the starting time place. This freedom allows lens designers to apply aspherical or freeform profiles in the lens blueprint opening upwardly additional performance advantages such as compact size and high image quality. Today almost all mobile camera lenses are made by injection molding method. A major disadvantage of plastic materials is that their index of refraction depends on the environmental temperature. This sensitivity to temperature makes the plastic elements unsuitable for some applications where an extreme temperature environment is expected. There are design techniques 1 can apply to "de-sensitize" lens designs with plastic elements. Sunex has successfully commercialized many hybrid lenses using a combination of plastic and drinking glass elements with such a blueprint strategy.
Molded drinking glass: The glass molding process overcomes the limitation of the drinking glass polishing process every bit outlined above (only flat or spherical surfaces tin be polished). Glass material tin be heated to a betoken where the fabric becomes soft. This soften point varies from glass to glass. The typical glass soften temperature is 500C to 600C. 1 starts with a glass preform made using machining or polishing process. The preform is then heated to the soften point and compressed betwixt two cavity surfaces of a mold. This forces the glass preform to take on the shape of the mold cavity surfaces. Once the preform is sufficiently cooled, the molded element is removed from the glass mold. The primal technical reward is that the surface shape tin can be aspherical or freeform while the material can exist glass instead of plastic. Glass materials have much better temperature and ecology stability making them suitable for a wide variety of applications where extreme temperature or harsh weather condition may exist encountered. The major disadvantage is that the molding process for drinking glass tin have a longer cycle fourth dimension compared with that of injection molding because of the higher soften temperature required for drinking glass. There are too limitations to the shape and materials that can be processed. Thus molded glass elements are only used in applications where this increased cost can be justified. If a design must use molded glass it is preferable to minimize the number of molded drinking glass elements to lower the manufacturing chance and cost.

For a lens pattern to be successfully produced in mass product it is important to choose the best blueprint strategy based on manufacturing process considerations. Should the blueprint be all polished glass elements? Should it contain molded plastic or glass elements? If yes, how many and where? Are the material choices and shape manufacturable by their corresponding processes? Can the required tolerances be accomplished? How to optimize the overall cost and yield? These questions crave in-depth process knowledge not captured past today'due south lens blueprint software such as Optics Studio or Code V. Talk to our engineers about your application requirement. Let us help you to brand your design more manufacturable.