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IEC 62629-1-2: 3D Display Devices — Terminology and Letter Symbols
IEC 62629-1-2:2013 establishes a standardized terminology and set of letter symbols for 3D display devices. As the first standardization effort in the IEC 62629 series, this document provides the foundational vocabulary needed for specifying, measuring, and comparing 3D display technologies across the consumer electronics, professional visualization, and medical imaging industries.
Scope: Covers generic terms related to 3D displays including stereoscopic, autostereoscopic, multi-view, and volumetric displays, along with associated performance specification terminology.
1. Classification of 3D Display Technologies
The standard classifies 3D displays into two primary categories:
| Category | Type | Principle | Examples |
|---|---|---|---|
| Stereoscopic | Time-sequential | Alternating left/right images synchronized with shutter glasses | Active shutter 3D TVs |
| Stereoscopic | Polarization-based | Simultaneous left/right images with orthogonal polarization | Passive polarized cinema |
| Stereoscopic | Spectral separation | Anaglyph (color filter) or spectral comb filtering | Anaglyph glasses, Infitec |
| Autostereoscopic | Parallax barrier | Opaque barrier with slits directing views to each eye | Nintendo 3DS, lenticular displays |
| Autostereoscopic | Lenticular lens | Array of cylindrical lenses directing different images | Multi-view digital signage |
| Autostereoscopic | Directional backlight | Time-sequential illumination from different angles | Head-tracked displays |
| Volumetric | True 3D | Voxels in physical space (rotating screen, stacked layers) | Medical imaging, scientific viz |
2. Key Terminology and Definitions
2.1 General Terms
- 3D display: A display device capable of conveying depth perception to a viewer
- Stereoscopic display: A 3D display requiring eyewear to separate left and right images
- Autostereoscopic display: A 3D display that provides depth perception without requiring special eyewear
- Multi-view display: An autostereoscopic display presenting more than two distinct views simultaneously
- Viewing zone: The region in space where a viewer perceives a correct 3D image
- Lobe: The angular region over which a single view is visible in an autostereoscopic display
Important Distinction: The standard carefully differentiates between “image” and “view.” An image is what is seen by one eye; a view is a perspective rendering. A multi-view display generates multiple views, each potentially seen by one or both eyes depending on viewer position.
2.2 Performance Specification Terms
| Term | Definition | Measurement Unit |
|---|---|---|
| Spatial resolution (3D) | Angular or spatial resolution perceived in the 3D image | Cycles per degree, pixels |
| Depth resolution | Minimum distinguishable depth difference | mm or dioptres |
| Crosstalk (3D) | Unwanted leakage of one view into another | Percent (%) |
| Luminance uniformity | Variation in brightness across the viewing zone | Percent (%) |
| Viewing angle | Angular range over which 3D perception is maintained | Degrees |
| Switching time (2D/3D) | Time to transition between 2D and 3D modes | Milliseconds (ms) |
3. Depth Perception and Display Design
The standard’s informative annexes explain the relationship between human depth perception and 3D display design. Key physiological depth cues include binocular disparity (the primary cue used by stereoscopic displays), accommodation (focus), convergence (eye rotation), and motion parallax. A well-designed 3D display must manage the vergence-accommodation conflict — the mismatch between where the eyes converge and where they focus — to prevent viewer fatigue.
Ergonomic Design Insight: The vergence-accommodation conflict is the primary cause of visual fatigue in 3D displays. Limiting depth range to within 1 dioptre of the display plane and providing smooth motion parallax significantly reduces viewer discomfort.
Engineering Design Insights
- Optical design of lenticular arrays — the pitch, focal length, and slant angle of lenticular lenses must be precisely matched to the underlying pixel grid to avoid moire patterns and ensure uniform view distribution
- Crosstalk management — optical crosstalk between views is the single biggest challenge in autostereoscopic displays; it can be minimized through black matrix optimization, lens profile shaping, and anti-aliasing filters
- Head tracking integration — combining autostereoscopic displays with eye/head tracking extends the usable viewing zone and enables personal 3D experiences without glasses
- Content-aware driving — 2D-to-3D conversion algorithms benefit from the standardized terminology to clearly specify depth map generation, inpainting of disoccluded regions, and view synthesis parameters
- Measurement standardisation — the letter symbols defined in this standard enable unambiguous specification of 3D display performance across manufacturers, essential for procurement and quality assurance
FAQs
Q: Why was IEC 62629-1-2 created as a terminology standard first?
A: Before performance requirements and measurement methods could be standardized, a common vocabulary was needed. The terminology standard provides the foundation for all subsequent 62629 series parts covering measurement methods and specification requirements.
Q: What is the difference between stereoscopic and autostereoscopic displays?
A: Stereoscopic displays require the viewer to wear special glasses (shutter, polarized, or anaglyph) to separate left and right images. Autostereoscopic displays achieve the same separation through optical means at the display surface — parallax barriers, lenticular lenses, or directional backlights — without requiring eyewear.
Q: How does crosstalk affect 3D display quality?
A: Crosstalk causes ghosting — each eye sees a faint remnant of the other eye’s image. At levels above 5%, crosstalk significantly degrades depth perception and causes visual fatigue. High-end 3D displays target below 1% crosstalk for comfortable viewing.