📺
Survey of Alternative Displays
  • Survey of Alternative Displays - 2024 Update Notes
  • 2022 Update Notes
  • Introduction
  • Outline
  • Standard Displays
    • Standard Displays Overview
    • LED
    • Projector
  • Alternative Displays
    • Overview
    • Transparent
    • Volumetric Displays
    • Modified Polarizers
    • Electronic Paper/E-Ink
    • Flexible Displays
    • Lasers and Laser Projectors
    • Lenticular and Multiview Displays
    • Light-field Displays
    • Head Mounted Displays
    • Circular and Non Rectangular
  • Techniques
    • Overview
    • Pepper's Ghost
    • Projection on Static Transparent Material
    • Volumetric Projection
    • Projection on Water or Fog
    • Diffusion and Distortion Techniques
  • Experimental/Other
    • Overview
    • Physical/Mechanical Displays
    • Switchable Glass
    • Drone Displays
    • Ultrasonic Atomization of Water
    • Electrochromic Paint
    • Light activated and other Reactive Surfaces and Materials
    • Scanning Fiber Optics
    • Acoustic Levitation Display
    • Plasma Combustion
    • High Refresh Rate Displays
    • Other Experiments
  • Legacy
    • Overview
    • Cathode Ray Tube
    • Eggcrate and other Numeric Displays
    • Glasses-enabled 3D
    • Pyrotechnics and Other Curiosities
  • Closing Notes
  • Appendix
    • Holograms and the Ideal Display
    • Misleading Terms
    • Notes about Touch Screens
    • Virtual Production and XR
    • LCD Polarizer Removal
    • DIY Transparent Screens
    • Acknowledgements and Additional References
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  • Holograms
  • Autostereoscopic Displays/3D TV's
  • LED TV's
  • 3D LED Displays and Forced Perspective

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  1. Appendix

Misleading Terms

PreviousHolograms and the Ideal DisplayNextNotes about Touch Screens

Last updated 11 months ago

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This section will cover some brief notes on frequently misleading terms used to market various displays. Here are a few:

  • 3D LED Displays and Forced Perspective

Holograms

When viewing close-by objects, there are six major depth cues that help us perceive three dimensions:

  • Perspective foreshortening: farther away objects appear smaller

  • Occlusion: nearer objects hide farther objects

  • Binocular parallax / stereopsis: left and right eyes see different views of the same objects

  • Monocular (motion) parallax: objects shift depending on how far away they are when head is moved

  • Convergence: eyes cross when focusing on close objects

  • Accommodation: eyes’ lenses change focus depending on objects’ distances

Almost all of the displays or techniques in this article have some holographic properties like parallax or multiple viewing angles, but are primarily in a class of their own. Would you call an oil painting a sculpture?

Autostereoscopic Displays/3D TV's

3D TV's are primarily a marketing term for something that is more accurately called an autostereoscopic display. These TV's aren't pushed as much in 2022 because they never really caught on for most of the public, primarily because they overpromised the 3D effect.

LED TV's

This term has been mixed up for a while and is more accurately known as an LED-Backlit TV.

3D LED Displays and Forced Perspective

There have been more and more of these kinds of videos popping up on social media in the last few years. While this isn't necessarily a misleading term, the way they are presented in a video setting is misleading to how they are percieved in real life.

In the first example below, the far end of the digital display is darkened so it looks like part of the building. When the hand passes into this part of the screen it looks as if there is building frontage behind it, tricking the viewer into thinking it must have reached out beyond the dimensions of the display. The illusion is spectacular when viewed from the right angle, but breaks down when the viewer moves to a different vantage point.

And here is a video that kind of debunks what these displays look like when moving around them in an actual city setting:

It should be mentioned that none of the displays mentioned in other sections are in line with the definition of a . A hologram is closer to a photographic medium as it captures an imprint of the light waves that bounce off an object. Most of the media headlines these days with the word “hologram” are typically talking about simple optical tricks or AR. Holograms have taken on a cultural meaning that differs from the scientific definition, similar to the cultural rebranding of “synesthesia” or “literally.” This by Oliver Reylos has a concise summary of what is considered holographic and what isn’t. In his words:

.

LED's as a light source were an important development for backlit LCD's many years ago and allowed the creation of thinner and more energy efficient LCD displays of the traditional CCFL (Cold Cathode Flourescent Light) light source. Unfortunately the marketing term causes them to be mixed up with which use a very different approach for creating light. There are more and more displays and TV's that are starting to use things like technology that will eventually make this even more confusing, but for now you can usually assume that an LED TV or monitor is usually only referring to the backlight.

where they explain this phenomenon fairly well:

There has been a great deal of hype in recent years around the use of various optical illusions such as forced or that make content on large format displays appear three dimensional—in particular using installations that wrap around the building like that at 20 Times Square. The advantage of the wrap-around design is that content can be used to create the impression that the screen is a large cube that has been cut out of the building. Action can then take place on this “stage” area that appears to extend back into the structure. If the stage area is smaller than the screen, objects can be made to appear as though they are moving out of the display.

hologram
article
More on various types of 3D Televisions
LED video displays
microLED
More on LED Backlit TV's
Light Field Labs has a breakdown
perspective
anamorphosis
Hologram
Autostereoscopic Displays/3D TV's
LED TV’s