plastic optics (original) (raw)

Definition: optical elements made of organic polymer materials

Alternative term: polymer optics

Category: article belongs to category general optics general optics

Related: optical materialsplastic optical fibersinfrared opticsultraviolet optics

Page views in 12 months: 1237

DOI: 10.61835/i75 Cite the article: BibTex BibLaTex plain textHTML Link to this page! LinkedIn

Content quality and neutrality are maintained according to our editorial policy.

📦 For purchasing plastic optics, use the RP Photonics Buyer's Guide — an expert-curated directory for finding all relevant suppliers, which also offers advanced purchasing assistance.

Contents

What is Plastic Optics?

Used Materials

Types of Optical Components

Typical Properties of Plastic Optics

Common Applications

Frequently Asked Questions

What are plastic optics?

What materials are typically used for plastic optics?

What are the main advantages and disadvantages of plastic optics compared to glass optics?

Why are aspheric lenses often made from plastics?

What are common applications for plastic optics?

Summary:

This article provides a comprehensive introduction to plastic optics, also known as polymer optics. It covers the common materials used, such as PMMA, polycarbonate, and polystyrene, and details their fabrication into optical components like lenses, prisms, and fibers.

Key properties of plastic optics are discussed in comparison to traditional optical glasses, highlighting advantages like low cost, light weight, and the ease of manufacturing aspheric and freeform surfaces. Disadvantages such as lower optical quality, higher temperature sensitivity, and unsuitability for high-power applications are also explained.

Finally, the article outlines a wide range of common applications, including ophthalmic lenses, miniature cameras for mobile devices, optical storage systems, and laser safety glasses.

(This summary was generated with AI based on the article content and has been reviewed by the article’s author.)

What is Plastic Optics?

There are various highly transparent organic polymer materials which can be used as optical materials for a range of applications. This area is called plastic optics or polymer optics. Due to their typically amorphous structures, these materials are also called organic glasses. In contrast, traditional optical glasses are inorganic glass materials.

Used Materials

Plastic optics are usually made from organic materials, with the major chemical constituents being carbon, hydrogen and oxygen. One starts with some kind of monomer substance, which is then subject to polymerization (sometimes in the form of polycondensation): macromolecules are formed by combining the monomers. The formed macromolecules usually have the form of chains, and those chains may also have additional connections.

Common polymer materials for optical applications are:

There are numerous trademarks for such materials.

Compared with plastics for other applications, optical plastics must be produced from high-quality pure materials with optimized processes to obtain reasonably good optical properties.

Types of Optical Components

Plastic objects are mostly used in the form of common bulk optical components like lenses (including microlenses), prisms and optical windows. An attractive feature for lenses is that aspheric lenses with high numerical aperture can easily be fabricated with molding and embossing processes — more easily and quickly than with most inorganic glasses. Even freeform optics can be made relatively easily. Also, one can make achromatic lenses, including apochromats, as composite lenses. In addition, it is advantageous that plastic optical components may be fabricated together with their mounts.

Plastic optics are often equipped with coatings for improving the mechanical durability. For example, ophthalmic glasses are often equipped with coatings based on organically modified silica layers. Anti-reflection properties can also be realized, typically with coating designs having four to six layers, e.g. of silica and tantalum pentoxide.Dielectric coatings can also be made as thin polymeric films, e.g. some amorphous fluoropolymer.

There are plastic optical fibers, which are e.g. used as multimode fibers for optical fiber communications over short distances. They are often made with a PMMA core and a cladding made from silicone resin.

Polymers are also used for some integrated optics devices, which may contain waveguides and other features.

Sometimes, special properties of polymers are exploited. For example, there are thermo-optic devices, exploiting the high (often strongly negative) thermo-optic coefficients of polymers. In other cases, optical nonlinearities are utilized.

Significant optical birefringence can be obtained simply by stretching a polymer material like polystyrene. Also, plastic polarizers can be relatively easily made. On the other hand, unwanted birefringence effects need to be avoided by careful process control e.g. in molding processes.

There are also micro-optics made from plastic materials. Indeed, polymer materials are often particularly suited for fabrication techniques as used for micro-optics.

Typical Properties of Plastic Optics

High light transmittance is usually obtained throughout the visible spectral region and to a limited extent in the near infrared. Often, there are absorption features at ≈1.7 μm due to the first overtones of C-H groups and additional absorption at longer wavelengths. However, absorption losses can be low in the three telecommunication windows around 850, 1310 and 1550 nm.

A primary driver for using plastic objects is the typically lower cost. This results from simple fabrication processes. For example, many polymer materials are suitable for molding processes, which are simple and quick and can even deliver aspheric surfaces.

On the other hand, the optical quality tends to be lower than that achievable with optical glasses. Therefore, glasses are still widely used for high-quality optical elements, despite their higher cost.

The refractive indices of optical polymer materials are typically between 1.4 and 1.7, thus similar to those of typical optical glasses. However, their temperature dependence is usually much stronger than for glasses (with strongly negative ($\partial n / \partial T$)), which is essentially caused by their strong thermal expansion (one to two orders of magnitude stronger than for typical glasses). Therefore, plastic optics tend to be much more temperature sensitive than glass optics. They are often suitable only for operating temperatures of up to 60 °C, although polycarbonate materials can be used up to 130 °C.

The wavelength dependence of the refractive index (→ chromatic dispersion) of polymers is relatively strong. This can be a problem, but in some cases the combination of strong dispersion with low refractive index, which is unusual for glasses, can be useful.

Plastics are typically quite soft, i.e., they can relatively easily be deformed or scratched, but also do not break as easily as glasses. For some applications, very soft transparent materials are needed, e.g. liquid silicone.

Most polymers are chemically less robust than glasses; for example, they may absorb water, which changes their properties.

The density of polymers is typically quite low, allowing the fabrication of lightweight components and devices.

Due to residual absorption and the typically quite low thermal conductivity, polymers are usually not suitable for applications involving high optical powers or intensities. Therefore and because of the limited optical quality, they are not common in laser optics.

Polymers can relatively easily be equipped with dyes, for example for use as optical filters based on wavelength-dependent absorption.

Common Applications

Plastic lenses are widely used in ophthalmology. For reading glasses and sunglasses, for example, the low weight and reduced fragility is advantageous in addition to the lower cost. Intra-ocular lenses and contact lenses are basically always made of polymers. Laser safety glasses are often made from polymers with added dyes for spectral filtering.

For mobile devices like smartphones and drones, miniature photo cameras are needed which are basically always based on plastic optics, often with small aspheric lenses. There would be no available space for objectives with multiple spherical lenses, as are typically used for large photo cameras. Impressive image quality is nowadays possible with extremely compact and low-cost camera designs.

Similar aspects apply to optical storage devices, e.g. with CD, DVD and blu-ray disks.

Further, various types of light reflectors are often made of plastics, for example for directing the output of light-emitting diodes.

Frequently Asked Questions

This FAQ section was generated with AI based on the article content and has been reviewed by the article’s author (RP).

What are plastic optics?

Plastic optics, also called polymer optics, are optical components made from highly transparent organic polymer materials. These materials are also known as organic glasses, in contrast to traditional inorganic optical glasses.

What materials are typically used for plastic optics?

Common materials include poly(methyl methacrylate) (PMMA, acrylic), polycarbonate (PC), polystyrene, and liquid silicone. These materials must be produced with high purity to achieve good optical properties.

What are the main advantages and disadvantages of plastic optics compared to glass optics?

Plastic optics are advantageous due to their lower cost, lighter weight, and easier fabrication of complex shapes like aspheric surfaces. However, they typically offer lower optical quality, are softer, more sensitive to temperature, and unsuitable for high-power applications.

Why are aspheric lenses often made from plastics?

Plastic materials are well-suited for molding and embossing processes, which can produce aspheric lenses with high numerical aperture more easily and quickly than the grinding and polishing methods typically used for inorganic glasses.

What are common applications for plastic optics?

Suppliers

Sponsored content: The RP Photonics Buyer's Guide contains 42 suppliers for plastic optics. Among them:

Shanghai Optics, supplier of plastic optics

âš™ hardware

plastic optics

Shanghai Optics produces the highest quality plastic optics in a variety of shapes, including aspheric lenses, optical prisms, cylinder lenses, toroid lenses, and free form optics. Our state of the art in house equipment allows us to use the most efficient ways to produce polymer optical components, including single point diamond turning and machining, CNC machining, and injection molding.

Injection molding is the most common way to manufacture large quantities of polymer optics. During the molding process melted thermoplastics are injected into prepared optical forms. Shanghai Optics has extensive experience in optics molding and especially in developing high quality molds for both standard and custom optics. Our optical design team has experience preparing both single cavity and multi-cavity molds, and molding acrylic (PMMA) lenses, polycarbonate lenses, cyclic olefin polymer lenses, etc.

Avantier, supplier of plastic optics

âš™ hardware

plastic optics

Avantier creates top-notch plastic optics in various shapes, like aspheric lenses, optical prisms, cylinder lenses, toroid lenses, and free form optics. We utilize state-of-the-art equipment, including single point diamond turning and machining, CNC machining, and injection molding to produce polymer optical components efficiently. Injection molding is the most common way we manufacture large quantities of polymer optics. Our experienced team can prepare both single and multi-cavity molds, molding different types of lenses like PMMA, polycarbonate, and cyclic olefin polymer lenses.

Aspheric manufacturing capabilities:

Sinoptix, supplier of plastic optics

âš™ hardware

plastic optics

We offer plastic injection lenses in PMMA, PC or COP, AR treatment possible. Plastic lens matrix and collimators are also available. Custom plastic optics.

Questions and Comments from Users

Here you can submit questions and comments. As far as they get accepted by the author, they will appear above this paragraph together with the author’s answer. The author will decide on acceptance based on certain criteria. Essentially, the issue must be of sufficiently broad interest.

Please do not enter personal data here. (See also our privacy declaration.) If you wish to receive personal feedback or consultancy from the author, please contact him, e.g. via e-mail.

By submitting the information, you give your consent to the potential publication of your inputs on our website according to our rules. (If you later retract your consent, we will delete those inputs.) As your inputs are first reviewed by the author, they may be published with some delay.