A holographic diffuser shapes light, it does not show a picture

What you see

A rear-projection screen, backlit sign, or LED fixture looks evenly bright edge to edge, with no visible hot spots, and keeps its brightness across a wide viewing angle rather than dimming from the side. Luminit's own page lists uses spanning 'automotive lighting, exterior/interior lighting, in stages and concert halls, projection systems, monitors and displays,' and landmark lighting installations.

How it works

Luminit's own technical page states its Light Shaping Diffusers use 'a surface relief microstructure, ranging from 3 to 80 microns, that creates a controlled angular distribution of light,' a pseudo-random pattern that 'reduces chromaticity issues, minimizes backscatter, and delivers high transmission efficiency.' Its separate FAQ page states the master pattern is made with 'our patented holographic master recording process': the microstructure begins as an interference pattern recorded once onto a master, then Luminit 'replicates' that pattern onto polycarbonate, acrylic, or glass sheet for volume production rather than recording a fresh pattern per sheet.

Viewing conditions and limits

The FAQ describes the diffusion angle in degrees of full-width half-maximum, 'the angle of diffusion that would be seen after a collimated laser passes through the diffuser,' with standard circular options from 0.5 to 100 degrees and elliptical options from about 10x0.2 to 95x35 degrees, so the usable viewing cone depends on which angle a given sheet is rated for, not on the word holographic alone. Because the pattern is 'random and non-periodic,' the FAQ states it is 'not wavelength-dependent,' working from 400 to 700 nanometres without the colour fringing a periodic grating would show. Glass versions are rated to 500 degrees Celsius; standard film is not.

What it is not

This is not a hologram of a scene in the sense used elsewhere in this guide; no picture is stored or reconstructed in it. 'Holographic' here describes only how the light-scattering microstructure was originated and then replicated, not any image the screen shows. The diffuser is closer in purpose to frosted glass than to a photographic hologram, built to control brightness and angle for whatever a separate projector or LED sends through it.

• What FWHM angle, or elliptical spread, is the specific sheet rated for, since that sets the usable viewing angle, not the word holographic?
• Is it the injection-moulded, film, or glass version, since heat tolerance and durability differ sharply?
• Does the technical sheet describe the microstructure as originated by holographic recording and replicated, or by another method?

Luminit's own pages describe a recorded-and-replicated microstructure that shapes light, a manufacturing description worth checking against any screen marketed simply as holographic.