IEC 63145-21-20:2022 - Eyewear display (VR) - Screen door effect (SDE)
Overview
IEC 63145-21-20:2022 specifies standard measurement conditions and methods for quantifying the screen door effect (SDE) in virtual reality (VR) eyewear displays. SDE is defined as the visibility of inter-pixel areas caused by limited spatial resolution or insufficient pixel fill-factor/aperture ratio. This part of the IEC 63145 series provides reproducible procedures for lab testing of SDE using imaging light measuring devices and defined test patterns.
Key topics and technical requirements
- Scope and purpose: Standardizes how to measure SDE as an image-quality metric for VR eyewear displays.
- Measurement systems: Defines the use of a 2D imaging light measuring device (LMD) with a two-dimensional sensor (e.g., CCD). Key LMD recommendations:
- Capture at least a ±2.5° measurement field; measurement field shall be less than 18°.
- Entrance pupil between 2 mm and 5 mm.
- Minimum performance example: 30 cycles per degree at 50% Michelson contrast at the entrance pupil.
- Standard conditions: Environmental, power, warm-up, and dark-room conditions follow IEC 63145-20-10 and IEC 63145-20-20.
- Test patterns: Prescribed patterns include:
- Checkerboard pattern (e.g., 5×5) for alignment and basic SDE observation.
- 4% colour window signal patterns (white, red, green, blue) for localized measurement.
- Measuring points: Centre (single-point) and multi-point (five- or nine-point) measurement layouts; positions can be specified in pixel coordinates or azimuth/elevation angles.
- Procedures and reporting: Includes preparations, measurement procedures, calculations (including Moving Window Average - MWA), and recommended reporting tables and figures. Informative annexes cover MWA algorithms, contrast modulation, visibility, and non-rectangular pixel layouts.
Practical applications and users
- Who uses it:
- VR headset manufacturers and display designers
- R&D and optical engineering teams optimizing pixel fill-factor and optics
- Test laboratories and quality assurance teams performing objective image-quality assessments
- Certification bodies and standards engineers comparing products or verifying compliance
- Why it’s useful:
- Enables consistent, repeatable quantification of SDE across products and labs
- Supports design decisions (pixel layout, optics, aperture) to reduce perceived SDE
- Useful for benchmarking, quality control, and research into perceptual visibility of pixel structure
Related standards
Keywords: IEC 63145-21-20:2022, eyewear display, VR, screen door effect, SDE measurement, 2D imaging LMD, checkerboard pattern, 4% window, pixel fill-factor, Moving Window Average.
Open preview (PDF)Eyewear display - Part 21-20: Specific measurement methods for VR image quality - Screen door effect
