Systemaufbau und Komponenten
A rugged camera stand carries the LCD monitor on which the samples to be measured are placed and provides continuous adjustment of the working distance of an electronic camera with a b/w sensor. For measurements of scattering and reflectance, a linear lamp is integrated in the optical head behind a slit with a width of 1 mm. Display monitor and sample sheets are placed on the base plate of the stand. The monitor or other display devices can be fixed with commercially available mounting clamps. Thread holes are provided in the base plate.
DEVICE UNDER TEST (DUT) – AG/AR SAMPLE AND DISPLAY
Since the sparkle effect is significantly influenced by the pixel geometry of the monitor, the measurement system can optionally be delivered with specific monitor types according to the application. The pixel shape and size are the determining parameters (please specify). On the other hand any monitor can be used, that can be placed horizontally on the base plate of the stand. The monitor can be exchanged for different applications.
MOTORIZED SHIFTING STAGE (OPTIONAL)
The system is delivered with a software package that automates the
measurements (depending on the equipment) and the evaluation of the
images. The picture at the right shows a sample dialog for sparkle measurement.
- LCD-monitor with a glossy screen as light-source
Best results are typically achieved with monochromatic green monitor image. However the color can be varied according to the application and requirements.
REFLECTANCE, SCATTERING, ANTI-REFLECTION FACTOR
Illumination: linear light source (CCFL).
The intensity of reflected light is recorded as a function of the location on the display.
The shape of the intensity curve describes the scattering characteristics of the AG-layer.
DISTINCTNESS OF IMAGE, MTF
Glossy display without surface treatment (right) and with AG coated glass (left). The image of the pixel array gets blurred.
Luminance modulation obtained from the figure above.
Red: without AG layer,
The scattering AG-layer reduces the amplitude and attenuates high-frequencycomponents (smoothing). A measure for the distinctness or blurring of an image is the Modulation Transfer Function (MTF):