What Are Infrared PMMA Filters?
Definition and Material Overview
Infrared-transmitting (IR) optical plastics are engineered polymer materials designed specifically for optical media applications. OPTOStokes infrared-transmitting acrylic (PMMA) filters—also referred to as IR window plates or IR-transmitting acrylic panels—are black or deep red substrates formulated from a polymethyl methacrylate base.
The defining characteristic of this material is its ability to completely block visible light while maintaining high transparency to near-infrared (NIR) radiation. It appears visually opaque black in the visible spectrum (400–700 nm, transmittance < 1%), while delivering 80% to 95% transmittance in the NIR region above 720–1100 nm. Exact transmission values vary based on component thickness, operational wavelength bands, and color specifications. These materials are widely used in optical instrumentation for manufacturing optical substrates, lenses, prisms, and window plates.
Optical plastics are classified by performance into thermoplastics and thermosetting plastics. Thermoplastics are polymers that can be repeatedly heated and reshaped. The majority of commercial optical plastics currently in use are thermoplastics; OPTOStokes primarily employs Polymethyl Methacrylate (PMMA) and Polycarbonate (PC) for our optical plastic products.
Physical and Optical Properties of PMMA (Acrylic)
PMMA is the most widely used optical plastic due to its excellent optical clarity, mechanical properties, and weather resistance. The table below summarizes the key properties of standard clear PMMA:
| Property | Value | Classification |
|---|---|---|
| Refractive Index (nd) | 1.491 | Crown optical material |
| Abbe Number (Vd) | 57.2 | Low dispersion |
| Visible Light Transmittance | ~92% | Standard clear grade |
| Accelerated Aging (240 hours) | Retains 92% transmittance | Excellent weatherability |
| Outdoor Exposure (10 years) | Retains 88% transmittance | Superior durability |
| Radiation Transmission | UV (>270 nm), X-rays, γ-rays | Absorbs neutron radiation |
OPTOStokes Proprietary IR-Transmitting Acrylic Panels
Leveraging imported raw materials and a proprietary in-house formulation, OPTOStokes IR-transmitting acrylic (PMMA) panels deliver optimal visible-light absorption paired with superior infrared transmission. Our panels outperform standard commercial IR acrylics in both spectral performance and mechanical durability.
Key performance characteristics of OPTOStokes IR PMMA filters:
Exceptional Spectral Performance: Complete visible-light blocking (400–700 nm, transmittance < 1%) for a solid black aesthetic, combined with outstanding NIR transmission (> 92%) across the 800–1600 nm band. Our filters are ideal for NIR filters applications requiring high signal-to-noise ratios.
Superior Mechanical Integrity: Exhibits excellent impact resistance and dimensional stability, making it suitable for diverse and demanding industrial environments.
Optional Surface Treatments: Anti-scratch hard coating (HC) processing is available to significantly enhance surface durability and scratch resistance, extending component lifespan in high-wear applications.
We manufacture custom optical windows and filter panels in a wide range of thicknesses, sizes, and shapes to meet your specific application requirements. Our robust production lines ensure predictable lead times and consistent quality for both prototype and volume production orders.
Key Applications
Infrared PMMA filters are used in a broad range of applications where visible light must be blocked while infrared radiation is transmitted. Common applications include:
Machine vision systems and industrial inspection equipment
Security and surveillance cameras with night vision capabilities
Infrared remote control receivers and gesture recognition systems
Biometric identification devices (fingerprint scanners, iris recognition)
Medical diagnostic equipment and NIR spectroscopy instruments
Automotive driver assistance systems (ADAS)
OPTOStokes Advantage
OPTOStokes maintains an extensive in-stock selection of standard infrared PMMA filters in common sizes and thicknesses, enabling fast delivery for urgent projects. For applications with unique requirements, we offer fully customized solutions including custom dimensions, special spectral formulations, and surface treatments.
All our IR acrylic filters undergo rigorous quality testing to ensure they meet or exceed specified performance parameters. Our commitment to world-class quality and technology ensures reliable performance in even the most demanding applications.
Get Expert Technical Support
Are you looking for high-performance infrared PMMA filters for your application? Do you require custom dimensions, special spectral characteristics, or anti-scratch surface treatments? Our team of optical engineering experts is ready to assist you.
Contact us at [email protected] to discuss your specific requirements, request technical consultation, or obtain a detailed quotation. We can help you select or design the optimal IR acrylic filter solution for your application.
