ZWB Glass Filter UV Optical Glass plate lens for UV Curing and Flame Sensor

Definition of ZWB Optical Glass plate:

In the diverse and specialized world of optical materials, ZWB glass stands as a critical enabler for applications operating in the ultraviolet (UV) region of the electromagnetic spectrum. The designation "ZWB" follows the German (Jena) glass classification system, where it is recognized as a specific type of UV-transmitting filter glass. Unlike standard optical glasses like BK7 or SF11, which are engineered for excellence in the visible spectrum, ZWB glass is meticulously formulated to achieve a unique and vital property: high transparency to short-wavelength UV radiation while effectively blocking visible and infrared light. This makes it an indispensable component in a wide array of scientific, industrial, and safety equipment.

Properties and Composition of ZWB Optical Glass plate:

The core characteristic of ZWB glass is its distinct spectral transmission profile. It exhibits excellent transmittance in the UV-B and UV-A ranges, typically from about 250-250 nanometers (nm) up to 400 nm. Its transmission curve peaks in this UV region and then drops off sharply, acting as a powerful barrier against visible light (400-700 nm). This behavior is the inverse of common tinted glasses that block UV and transmit visible light.

This unique property is not accidental but is achieved through a specific chemical composition. Traditional ZWB glass is a phosphate-based glass doped with high concentrations of nickel oxide (NiO). The nickel ions within the glass matrix are responsible for its characteristic deep blue-green or almost black appearance to the human eye. These ions possess specific electronic energy levels that absorb photons in the visible spectrum, preventing them from passing through. However, the energy of UV photons is either mismatched with these absorption bands or is sufficient to bypass them, allowing the UV radiation to transmit through the glass with relatively low loss. This fundamental principle makes ZWB glass what is known as a "black glass" UV filter.

Features of ZWB optical glass plate:

High UV Transmission: It allows ultraviolet light to pass through while effectively blocking most visible and infrared light.

Absorbs Visible Light: It appears deep blue or almost black because it absorbs yellow, green, and red wavelengths.

"Black Blue" Glass: Often referred to as a "black blue" glass due to its dark appearance under ambient light.

Applications of ZWB glass plate:

The ability to isolate and transmit pure UV light makes ZWB glass invaluable in numerous fields:

UV Curing and Industrial Processing: One of the most widespread applications is in UV curing systems used in printing, coating, and adhesive bonding. High-pressure mercury or UV-LED lamps emit a broad spectrum of light. ZWB filters are placed in front of these lamps to absorb the visible and infrared components, delivering a concentrated, "cool" beam of UV energy. This pure UV light efficiently initiates the photochemical reaction in UV-curable resins without causing unwanted heat damage to sensitive substrates.

Fluorescence and Spectroscopy: In scientific instrumentation, ZWB glass is crucial as an excitation filter. In fluorescence microscopes and spectrofluorometers, a bright light source (like a xenon lamp) is used. A ZWB filter is placed in the excitation path to provide a clean, monochromatic-looking UV light that strikes the sample. This excites the fluorophores, causing them to emit light at a longer wavelength (visible light), which is then observed or measured through another filter that blocks the UV. This separation of excitation and emission light is fundamental to fluorescence techniques.

Forensic and Chemical Analysis: In forensic science, ZWB filters are used in specialized UV lights to reveal latent fingerprints, bodily fluids, and other evidence that fluoresces under UV illumination. Similarly, in chemistry, it is used to analyze minerals, detect counterfeit banknotes, and study chemical reactions that are photosensitive in the UV range.

Phototherapy and Medical Devices: Certain medical treatments, such as phototherapy for skin conditions like psoriasis and vitiligo, require controlled exposure to specific UV wavelengths. ZWB filters can be used to shape the output of therapeutic lamps, ensuring the patient is exposed only to the therapeutically beneficial UV-A or narrowband UV-B radiation while filtering out harmful or unnecessary wavelengths.

Lighting and Sanitization: While not the primary filter for germicidal UVC (254 nm) lamps, ZWB-type glasses can be used in applications where the specific UV transmission band aligns with the disinfection requirements, ensuring that no visible blue light leaks from the device.

Technical Specifications