Circular Variable Neutral Density Filter

1. Features

• Adjustable Light Attenuation: The circular variable neutral density filter allows for precise attenuation of light by rotating the filter, enabling linear adjustment of light intensity.
• Wide Wavelength Range: The filter is designed to cover wavelengths from 380 nm to 2500 nm, making it versatile for various applications.
• Durable Construction: Made from K9 material, ensuring high durability and optimal optical performance.
• Precise Optical Performance: Coated with anti-reflection coatings to maintain high transmission and low reflection across the operating wavelength range.
• Customizable Sizes and Specifications: Available in a variety of sizes and densities to meet specific application requirements, with customization options available.

2. General Description

Shape Optics Technologies Pte Ltd (SOT) offers high-performance Circular Variable Neutral Density Filters designed for light attenuation in optical systems. These filters provide a variable, linear attenuation of light as the filter is rotated, enabling precise control of the intensity of transmitted light. The filters are suitable for both white light and laser applications, offering flexibility for use in a wide range of settings.

These neutral density filters are constructed from K9 optical material, ensuring high optical quality and durability. The coated filters provide excellent performance with a wide wavelength range from 380 nm to 2500 nm, covering both visible and infrared spectra. The filter’s design allows for attenuation of light in a large finite aperture by using counter-rotating filters, which provides even greater flexibility in optical setups.

SOT’s circular variable neutral density filters are available in various sizes, including 25mm, 50mm, 60mm, and 100mm diameters, with customizable designs to meet specific customer needs. These filters are ideal for use in scientific instruments, laser systems, and optical measurement applications that require precise and adjustable light control.

3. Spectrum Transmission Curves

If the standard components do not meet the specific requirements for your application, SOT offers customized solutions. Upon request, we can provide filters designed to match your exact transmission and density requirements.

4. Coating Quality

• Adhesion Test: The filters comply with MIL-C-675C military standards for adhesion. The adhesion test involved applying a tape that meets LT-90 specifications onto the lens film layer, which was then removed vertically. After three repetitions, there was no blistering or peeling of the coating.
• Temperature Test: Following MIL-C-675C specifications, the filters were subjected to temperatures ranging from -62±1°C to 71±1°C. After two hours at room temperature (16°C-32°C), the adhesion test showed no film detachment.
• Abrasion Resistance Test: In compliance with MIL-C-675C and CCC-C-440 standards, the abrasion resistance test involved applying a minimum force of 1.0 lbs (0.45 kg) with a gauze tester. After 25 cycles with gauze widths of 1/4 inch (6.4mm) and 3/8 inch (9.5mm), the film surface showed no damage.
• Humidity Test: The filters were placed in a temperature and humidity chamber (49 ±2°C and 95%-100% humidity for 24 hours) under MIL-C-675C criteria. After this, the film remained intact with no peeling, scratches, or defects.
• Solvent and Cleaning Test: Following MIL-C-675C standards, the filters were exposed to acetone and alcohol at room temperature for at least 10 minutes each. After air drying and cleaning with an alcohol-soaked cotton cloth, there was no peeling or scratching of the film surface.
• Salt Spray Test: After 100 hours in a 35°C environment with a 5% saltwater concentration, no damage was observed on the film.

5. Standard Specifications

The Circular Variable Neutral Density Filter comes with the following standard specifications:

6. General Applications and Examples

The Circular Variable Neutral Density Filter is essential in various applications, especially where precise control over light intensity is required. These include:

• Scientific Instruments: Ideal for use in spectroscopy, optical testing, and experiments where varying light intensities are crucial.
• Laser Systems: The filters can be used to attenuate laser light in experimental setups and optical measurement systems.
• Optical Measurement Devices: In applications such as imaging, fluorescence microscopy, and biochemical analysis, these filters provide flexible light control for consistent and reliable results.

The unique feature of rotating to adjust light attenuation makes these filters versatile in both research and industrial settings where accurate light manipulation is required.

7. SOT Strengths and Capabilities

Shape Optics Technologies (SOT) is committed to excellence in optical component manufacturing, offering high-performance solutions that meet the rigorous needs of modern optical applications. With extensive expertise in custom filter design and production, SOT provides precise optical components such as circular variable neutral density filters, which ensure superior performance in both laboratory and industrial environments. Our ability to produce high-quality, customized optical filters and coatings ensures that we can meet the unique specifications of our clients, making SOT a trusted partner for high-precision optical solutions.

8. Standard Products

The Circular Variable Neutral Density Filter is available in the following standard configurations:

Custom configurations are available upon request. Please contact us to discuss your specific requirements.