Glossary of terms

We will review some commonly used terms both in virtual reality, as well as augmented and mixed reality.

Pixels per inch or PPI

A Measure that relates the number of pixels to the inches in a screen.

For the same screen size, the higher the PPI, the higher the screen resolution and the smaller the pixel size.

Pixels per inch PPI

Screen Door effect or SDE

It Is The effect by which the edges of the pixels in the images are appreciated. This effect can be annoying, cause dizziness if the visors are used for a long time and makes it difficult to dive.

Solutions to palliate it are a higher resolution of screen or other technologies, like the increase of the feeling of PPI.

SDE or Grid effect

 Uncanny Valley

Hypothesis that claims that human forms that look too much like real, cause rejection of the view of the user.

In this way, the user’s virtual hand, viewed with a viewfinder, that keeps real proportions very close to reality, would cause repulsion by the user.


The Moving image on the screen shows a wake because the pixels that border the image take a change in brightness (response time).

Ghosting Image

Rays of God (Glare)

Circular Blurring of the image caused by the rings that make up the lenses (for example in Fresnel lenses), consisting of circular grooves.

These concentric circles are usually accentuated with great contrasts of luminosity, causing enough annoyance to the user.

Ray of God or glare


FOV-Field of view

Perceivable Angle by the human eye of the virtual scene. This feature defines the size of what you see in the image.

FOV Field of view

Motion Blur

Effect on which objects give the feeling of leaving a trail when they are moving. This unpleasant effect may cause dizziness or loss of immersion.

Some of the solutions to this problem is to decrease the viewing time of the pixels or increase the rate of soda.

Motion Blur Motion Blurring

Fresnel Lenses.

Design for high-aperture lenses and short focal length, preserving an ideal weight and volume for virtual reality viewfinders.

One of its most relevant features of these convex flat lenses are concentric ring cuts.

Fresnel Lenses

Motion sickness

Disorder produced in the organism due to movement It Usually occurs because of the difference between what you see with the viewfinder and what our organism feels. Dizziness or disorientation is One of the immediate effects.