Verify Consistent Color of Coated Glass Panes

Thermal insulation and solar control coatings reduce heating and cooling costs and add color to architectural glass. To ensure all windows will match once installed, coaters must use the right solution to quantify color on non-scattering surfaces.

Challenge

Controlling the color of coated glass panes holds many challenges:

• Silver layers, thermal insulation, and solar coatings affect the color of the pane
• All panes must match once installed; any color deviation will be easily noticed
• Since glass is non-scattering, conventional inline measurement devices with direct illumination cannot provide accurate color data
• Glass that looks correct on the line may exhibit defects once installed

Solution

A color measurement solution from X-Rite can take contactless measurements to evaluate color and gloss on coated glass panes. The system includes the ColorXRA G3 non-contact spectrophotometer with a Xenon flash lamp to illuminate both UV and visible range and take measurements every second. With a DE* of <0.3 on typical glass samples and repeatability of DE* <0.1 on the calibration mirror, it delivers the same readings as a sphere geometry measurement. The device can be mounted above the pane to take reflectance measurements, or below the pane to capture transmission, too.

ESWin software displays measurement results to characterize glass and coating color so operators can make clear pass/fail decisions, adjust color processes, and ensure glass is in tolerance before shipment. ESWin software also documents color quality records to verify the integrity of the program according to ISO 9001 and identify areas of improvement.

Results

• Improve manufacturing output
• Reduce waste due to color shift
• Detects color issues before installation to avoids the expense of tearing out and reinstalling windows.

How it Works

The ColorXRA G3 can be mounted on a traversing beam for inline measurements above the line or on a stand for QC measurements in the lab. Both devices take non-contact measurements to capture accurate readings, regardless of thickness, without manually adjusting the measurement head.

For multi-silver layer measurements:

• The ColorXRA G3 is mounted 20 mm from the glass pane. It illuminates and picks up from multiple viewing angles (+15° : -15°, +45° : -45°, and +60° : -60°) to show color changes from different observer angles.
• This device captures simultaneous measurements of all geometries to fully quantify color and gloss. A second device can be mounted below the pane for transmission measurements.

For ±15° reflectance and transmission measurements:

• The ColorXRA G3 is mounted 31 mm from the pane. It illuminates the glass at a reflectance angle of 15° and captures a measurement at -15°.
• This device can be mounted above the pane to capture sun protection measurements. A second device can be mounted below to measure functional layers such as low-E and solar protection.

Measurement data is transferred to ESWin software to evaluate whether coatings are within tolerance and consistent before shipment.

Featured Products

ColorXRA G3 Spectrophotometer
Mounted inline or in the lab, this multi-geometry instrument measures from three different angles to replicate how color will shift when viewing angle changes. It offers a spectral range from 330 nm to 1000 nm with 1 nm optical resolution for best-in-class measurement results. Real dual beam measurement delivers excellent short-term stability and automatic wavelength accuracy of <0.1 nm ensures exceptional measurement accuracy and long-term stability.

ESWin CLCC Software
Quality control software that works with the ColorXRA G3 inline instruments to evaluate the color and gloss of functional layers on glass. It presents measurement results in an easy-to-interpret graphic display so operators can make clear pass/fail decisions on the production line and documents color quality records to verify the integrity of the program according to ISO 9001 and identify areas of improvement.

ESWin Quality Control Software
Quality control software that works with the ColorXRA G3 laboratory instruments to evaluate the color and gloss of functional layers on glass. It presents measurement results in an easy-to-interpret graphic display so operators can make clear pass/fail decisions in the lab and documents color quality records to verify the integrity of the program according to ISO 9001 and identify areas of improvement.

Custom Traversing Beam
A customized aluminum frame that can be built to fit any production line and mount the inline spectrophotometer above the web for continuous non-contact measurements from left to center to right.

Achieve Color Compliance

Using the ColorXRA G3 spectrophotometer ESWin quality control software, glass coaters can measure silver layers, thermal insulation, and solar coatings to ensure each pane is within color tolerance before shipment for a harmonious installation.