Microscope Lens

Specially-designed lens option for high-resolution imaging of small light source and display features

Evaluate Individual Display Pixels

As displays gain resolution and pixel-density, there is an increasing need to measure much smaller light-emitting elements to ensure accuracy of light output, color, and other qualities. This is especially true of emissive displays like OLED, LED, or microLED, where each pixel in a display produces its own luminance and therefore can vary in output from pixel to pixel. These individual variations can cause non-uniformity of the display that is visible even at a distance, especially when viewing the display at high bright states. Once measured, discrepancies in output from pixel to pixel can be calculated and applied as corrections. This normalization of pixel outputs produces a display of entirely uniform appearance. These calibrations can be carried over from design to ensure accurate pixel output for the given substrate or pixel layout of devices in production operations.

Characterize Subpixel Patterns

Subpixel patterns like those shown in the image here can be challenging to characterize without a very high-resolution system and optics capable of microscopic measurement. The Microscope Lens provides 5X or 10X magnification of images captured by high-resolution imaging systems (up to 43MP) to enable design manufacturers to ensure accurate subpixel layouts, shapes, and RGB color patterns. As shown, we can achieve extreme detail in a very small spatial area to properly image individual elements with a substantial amount of separation between light regions.

Characterizing Individual LEDs

The physical structure of LEDs (diode sources) is more complex than most other lamp sources. Imperfections in brightness and color can occur due to material, mechanical, or electrical defects within each emitter. Evaluation of individual LEDs may be critical for ensuring the performance of LED-based systems, and the uniformity of brightness and color when LEDs are combined in an array.

The Radiant Microscope Lens can be used to evaluate properties of LEDs alone or in an array, including:

  • LED uniformity
  • LED edge contrast (uniformity falloff)
  • Effect of cross-talk between LEDs (undesired illumination of an LED by a neighboring LED on an array or panel)
  • Cross-section plots showing LED luminance uniformity

Measurement image of a single LED (left) and cross-section showing edge contrast of the LED (right), where luminance level falls off over a given distance in millimeters. Results shown in TrueTest Software.
 

The Microscope Lens is an optional mounting accessory for Radiant’s ProMetric Y Imaging Photometer or ProMetric I Imaging Colorimeter, which attaches using a custom mounting bracket for stability. By mounting a lens directly to a ProMetric imaging photometer or colorimeter, the lens offers a complete solution and the most efficient means of measuring displays with minimal setup and integration time, equipment, or expertise. The Microscope Lens can easily be removed and replaced with standard lenses for additional measurement applications, including measurements that require the full display field of view, such as uniformity of luminance and chromaticity, contrast, mura, and other features.

Microscope Lens Key Features and Highlights:

  • Accurate, reliable measurement of display luminance and chromaticity
  • 5X microscope and add-on 2X teleconverter (converts 5X to 10X lens)
  • Imaging for multiple data points, increasing measurement efficiency
  • Magnification of details captured by high-resolution CCDs (to 43 megapixels)
  • Combination of value, high performance, and flexibility, designed for R&D and quality assurance
  • Easy-to-use measurement control and analysis software

All Radiant ProMetric camera solutions come with ProMetric Software, a powerful software suite that provides intuitive camera setup and control, data acquisition and image analysis. Extensive data analysis and display functions are also supported, including isometric plots, cross-section graphs, radar plots, bitmaps, and CIE color plots. For additional measurement and test sequencing options, TrueTest Software offers the comprehensive range of Radiant display measurement capability.

Typical Applications:

The Microscope Lens is ideal for capturing small details in extremely high resolution. The camera/lens solution offers photometric imaging efficiency to address both off-line and in-line applications:

  • High-resolution imaging of extremely small components and component features
  • Evaluation of display pixels and pixel structures (including subpixel level)
  • Evaluation of individual LEDs, including microLEDs
  • Characterization for display design and R&D
  • Measurement for quality control at end-of-line