How to Use Ultraviolet Fused Silica Window Plate

How to Use ULTRAVIOLET FUSED SILICA WINDOW PLATE (Technical Instructions)

UltraOpto ULTRAVIOLET FUSED SILICA WINDOW PLATE (UV Fused Silica Window Plate) features high UV transmittance, low hydroxyl content, excellent thermal stability and optical uniformity. It is widely used in deep-ultraviolet lithography, excimer laser systems, UV spectroscopy, semiconductor detection and other high-end optical scenarios. The correct use method directly determines whether the product can exert its optimal performance and extend its service life. The following is a standardized operation guide for the whole process.

I. Pre-use Preparation (Core Premise to Avoid Performance Loss)

Product Parameter Verification & Appearance Inspection

Parameter Matching: Before use, confirm that the model, size, thickness, UV transmittance (especially the key band such as 193nm/248nm) and surface quality grade of the window plate match the requirements of the optical system. Avoid performance mismatch caused by parameter inconsistency.

Appearance Inspection: 

Conduct visual inspection in a Class 100 clean environment. Ensure the optical surface is free of scratches, stains, mold spots and coating peeling, and the edge is free of chipping and corner damage. Defective products will cause light scattering and affect the accuracy of the optical system.

Unpacking Standard: 

Operators must wear clean anti-static clothing and anti-static gloves. Avoid direct contact between skin oil and sweat and the optical surface. Unpack the product only before use; if not used temporarily, rewrap it with anti-static optical special paper and store it in a clean protective box.

Environment & Equipment Preparation

Environment Requirements: 

The use environment should maintain a constant temperature of 20±2℃ and a relative humidity of 30%-50%. Avoid using it in high humidity, high dust and temperature shock environments to prevent surface condensation and dust adsorption. For deep-ultraviolet high-precision scenarios, it is recommended to use it in a Class 1000 clean room equipped with a HEPA filter.

Equipment Debugging: 

Pre-adjust the optical system to ensure that the light source, optical path and detector are in normal working state. The optical path should be aligned without deviation, and the light intensity should be adjusted within the bearing range of the window plate to avoid damage to the optical surface caused by high-energy laser long-term irradiation.

II. Correct Installation Steps (Precision Installation to Ensure Optical Path Accuracy)

Installation Method Selection (Adapt to Different Optical Systems)

Threaded Installation: 

Circular window plates with standard threads can be directly screwed into the threaded interface of optical lenses or lens holders. Apply uniform force during screwing to avoid deformation of the window plate or damage to the thread due to excessive force. After installation, ensure the window plate is perpendicular to the optical path (perpendicularity deviation ≤ 0.1arcmin).

Clamp Installation: 

Square, special-shaped or non-threaded circular window plates are fixed with special optical clamps. The clamp should adopt a stress-free design, and only clamp the non-optical edge area of the window plate to avoid pressing the optical surface and ensure the window plate is flat without offset.

Embedded Installation: 

In integrated optical systems, insert the window plate into the special card slot. The slot size should match the window plate (tolerance ≤ ±0.1mm). Push it into place gently to avoid bumping the edge. After installation, check whether the window plate is coaxial with the optical path.

Key Installation Points

Optical Path Alignment: 

Ensure the optical center of the window plate coincides with the optical path center during installation, with a deviation ≤ 0.05mm. Avoid optical path offset leading to transmittance reduction and wavelength drift.

Direction Confirmation: 

Some high-precision UV fused silica window plates have front and back sides (marked with "IN" for incident surface and "OUT" for emergent surface). Install according to the mark to avoid significant attenuation of UV transmittance caused by reverse installation.

Stress-free Installation: 

No matter which installation method is adopted, avoid external force extrusion and bending of the window plate to prevent stress from damaging the internal structure of the fused silica and affecting optical uniformity.

III. In-use Debugging & Control (Exert Optimal Performance)

Optical Performance Debugging

Transmittance Verification: 

After installation, use an ultraviolet-visible spectrophotometer to detect the actual transmittance of the window plate in the target band (such as 193nm). Confirm that it is consistent with the factory parameters. If there is a deviation, fine-tune the installation angle or optical path position until it meets the standard.

Laser Power Adaptation: 

In high-power excimer laser scenarios, it must be used with an attenuator to control the incident laser power density within the laser damage threshold of the window plate (UltraOpto standard model ≥ 200mJ/cm²@193nm, 10ns pulse). Avoid film layer damage or substrate cracking caused by excessive power.

Contamination Prevention: 

During use, install a dust cover or protective window on the optical system to prevent dust, oil fume and other impurities from adhering to the surface of the window plate. If there is slight contamination, handle it in time (see Section IV for cleaning methods).

In-use Precautions

Avoid Long-term Strong Light Irradiation: When not in use, turn off the light source or cover the window plate in time. Avoid long-term irradiation of high-energy UV light leading to aging of the optical surface and reduction of transmittance.

Prohibit Random Wiping: Do not touch or wipe the optical surface with hands, ordinary paper towels or rags. Hard fibers will scratch the optical surface and affect light transmission.

Avoid Chemical Corrosion: Do not contact the window plate with corrosive substances such as acid, alkali and organic solvents to prevent surface corrosion and performance degradation.

IV. Post-use Maintenance & Storage (Extend Service Life)

Standard Cleaning Process

Surface Dust Removal: 

In a clean environment, use a dust-free air blower to blow off the surface dust along the same direction. Do not use high-pressure air to avoid damaging the optical surface.

Stain Cleaning: 

For stubborn stains, dip a dust-free cotton swab in anhydrous ethanol or special optical cleaner, and gently wipe along the same direction. Avoid repeated wiping to prevent scratches.

Drying Treatment: 

After cleaning, dry the surface with nitrogen gas, and place it in a clean environment to air-dry naturally. Do not use a hair dryer or high-temperature heating to avoid thermal stress deformation.

Standard Storage Requirements

Packaging Requirements: 

After cleaning, wrap it with anti-static optical special paper, put it into a customized hard plastic protective box, and fill the box with dust-free sponge to fix the position and avoid shaking and collision.

Environment Requirements: 

The storage environment should be kept clean, shaded, constant temperature (18-25℃) and constant humidity (30%-50%RH). Avoid storing in high temperature, high humidity and strong light environments. Follow the first-in, first-out inventory management principle.

Special Storage for Coated Products: 

For UV fused silica window plates with anti-reflection coating, vacuum packaging is recommended for storage to isolate oxygen and water vapor and prevent coating oxidation.

V. Common Problems & Solutions

Reduced UV Transmittance: 

Check whether the surface is contaminated or the coating is damaged. Clean the surface or replace the window plate; if it is caused by optical path deviation, fine-tune the optical path position.

Optical Path Distortion: 

Check whether the window plate is stressed or deformed, and replace the clamp with a stress-free design; at the same time, check whether the substrate is cracked and replace the defective product in time.

Surface Condensation: 

Check whether the use environment humidity exceeds the standard, and improve the environmental humidity control; wipe the condensation with a dust-free cotton swab in time to avoid water stains.

UltraOpto UV fused silica window plate can maintain high-precision optical performance for a long time through standardized installation, debugging and maintenance, providing reliable support for deep-ultraviolet optical systems such as lithography and laser detection. For customized use solutions of special scenarios, please contact UltraOpto technical team.