White Papers

Detailed information on our technology and solutions, written by industry experts.

Optical Tests for Automotive Displays

In today’s world the very high picture quality of smartphones and tablets is also expected by consumers for displays in cars. Therefore, the tests commonly used in consumer electronics in development, production and quality assurance should also be applied in the automotive

industry. However, procedures that have been used so far and the use of simple image processing cameras often do not do justice to the task at hand. The displays used in automobiles are developing rapidly. The size and the resolution are constantly increasing to the extent that the 15.6 inch diagonals and 1920 x 1200 pixels find their way into the middle class.

Published by Automobil Elektronik I all-electronics.de on October 22, 2019.

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Methods for Measuring Small Defects in Automotive Curved Displays

Curved displays offer manufacturers new design flexibility for vehicle interiors, but also introduce challenges for display measurement. This paper presents the results of several lab tests measuring a 1500R LED-lit curved display using an imaging colorimeter and analysis software to evaluate the effectiveness of various methods and system specifications to

optimize the accuracy of small defect detection (pixels and lines) in automotive curved displays.

In this White Paper, you will learn:

  • The impact of curved displays on automotive design and human visual comfort
  • Radiant parameters for lab-based testing of line and pixel defect analysis in curved displays
  • Results of testing based on the application of various system resolutions (to 16 megapixels) and depths of field (to F/13)
  • Results of testing based on the use of different test methods, including single-channel analysis, multi-channel analysis, and multi-image analysis
  • Recommended curved display test methods for labs and production environments

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Understanding Imaging System Specifications for Pixel-Level Measurement of Displays: Comparing Measurement Performance of Current CCD and CMOS Sensors

Imaging systems rely on sensors to accurately interpret light as photometric data and enable evaluation of displays. This paper discusses properties of today’s high-resolution sensors used for image-based photometric display testing.

It examines measurement examples to compare sensor type (CCD versus CMOS), pixel size, and signal-to-noise ratio (SNR), and the effect of these properties on the accuracy and repeatability of data for pixel-level display measurement.

In this White Paper, you will learn about:

  • Pixel-level display measurement challenges
  • Importance of measurement repeatability and precision
  • Measurement system specifications
    • Resolution
    • Signal-to-Noise Ratio (SNR)
    • Photo-sensor size and well capacity
    • Photon Transfer Curve (PTC)
  • A comparison of today's CCD vs. CMOS performance for pixel-level measurement

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Method for Repeatable Measurement of Sparkle in Anti-Glare Displays

Anti-glare (AG) films are applied to displays to minimize reflections from ambient light and ensure that important information is viewable. However, displays that use these films and coatings are prone to a visual effect called sparkle, which causes low display clarity that can appear grainy to a human observer.

Measuring perceived sparkle ensures that the quality standard for AG displays is driven by the intended experience of the viewer. Such a measurement can be used not only in quality control during display production, but also in supplier qualification by OEMs who source third-party displays for integration. This paper describes precise geometric, optical, and software parameters of a sparkle measurement method, which has been proven to match human visual perception of display quality with repeatable results. Using this method, OEMs and manufacturers of displays can define precise, measurable tolerances for sparkle and establish standard quality control processes for anti-glare (AG) displays.

In this White Paper, you will learn about:

  • Anti-glare (AG) layer properties and their effect on visual display quality
  • Tools for isolating sparkle for accurate AG display measurement
  • System and measurement parameters that enable repeatable quantification of sparkle percentage
  • How data has been correlated with human perception of display quality

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How to Use Imaging Colorimeters for Automated Visual Inspection of Displays

The use of imaging colorimeters and associated analytical software for automated visual inspection (AVI) of displays is well established. A fundamental difference between imaging colorimetry and traditional machine vision is imaging colorimetry’s accuracy when it comes to matching human visual perception of the properties of light. This white paper describes how imaging colorimetry can be used in a fully-automated test system to identify and quantify defects in high-speed, high-volume production environments.

This white paper describes how imaging colorimetry can be used in a fully-automated testing system to identify and quantify defects in high-speed, high-volume production environments.

In this White Paper, you will learn about:

  • Differences between display inspection methods
  • Measurement components and setup of imaging colorimeter-based display test systems
  • Using AVI to detect common defects in displays to determine repair, reject, or accept actions

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Guide to CCD-Based Imaging Colorimeters

Specially calibrated to replicate human spatial perception of brightness and color, imaging colorimeters and photometers are ideal in a broad range of measurement and inspection applications. With multiple options for CCDs, control electronics, filters, and lenses, these powerful tools can be tailored to meet a your specific application requirements.

Selecting the right CCD-based imaging colorimeter requires understanding a few basic trade-offs in imaging colorimeter architecture. This guide will help you determine right configuration for your needs.

In this White Paper, you will learn about:

  • CCD technology
  • Noise reduction and types of noise
  • Color accuracy related to filters
  • Types of measurement errors and their causes
  • How to choose the best imaging colorimeter for your application

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Automated Solutions for SAE Standard HUD Measurement

Head-up display (HUD) technology is one of the largest growth areas in the automotive market, and standard measurement criteria are rapidly being defined to evaluate HUD performance for quality and safety.

This paper introduces methods for meeting the requirements of the new SAE J1757-2 standard and outlines the advantages of automated measurement systems.

In this White Paper, you will learn about:

  • The SAE (Society of Automotive Engineers) new standard for measuring HUDs: SAE J1767-2
  • Advantages and disadvantages of current SAE-compliant HUD measurement systems
  • Automated Alternatives to current test methods: imaging colorimeters and photometers
  • How automation simplifies SAE measurement criteria

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How to Use Imaging Colorimeters to Correct OLED, MicroLED, and Other Emissive Displays for Improved Production Efficiency and Yields

Emissive OLED, microLED (μLED), and miniLED are emerging as the next wave of technology in the display market. This is exciting because these displays promise improved display performance and visual appearance with greater efficiency than other display technologies, thanks to their individually emissive pixel elements. As manufacturers work to launch commercially viable OLED and microLED displays, high costs due to manufacturing yield issues have hindered widespread technology adoption, most dramatically in large-format implementations, since they drive up consumer prices.

The application of imaging colorimeters improves OLED and microLED display production by ensuring visual quality of displays—measuring brightness and color uniformity at the pixel and subpixel level to correct poor quality displays and safeguard manufacturing investment. An imaging colorimeter system is one very important component in manufacturing processes that boosts efficiency and yields in display production, ensuring optimal price/performance.

In this White Paper you will learn about:

  • Manufacturing challenges of OLED and microLED technology
  • Applications of imaging colorimeters in emissive display measurement and manufacturing
  • The process of "demura" for display measurement and correction
  • How correcting emissive displays improves yield and supports market growth

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