At the Consumer Electronics Show (CES 2024 ) in Las Vegas, Zeiss demonstrated a new technology that opens up completely new fields of application in a transparent glass surface. The 
"Multifunctional Smart Glass" is intended to enable "the optical activation of transparent media" - for example for projection, touch, lighting and filtering applications.
The interesting thing about the new technology is that not only can objects be shown in a kind of transparent display, but also, for example, a transparent and therefore invisible camera can be realized in a pane of glass.
Invisible camera in a pane of glass - Zeiss Holocam
Such a "Holocam" uses holographic coupling, light guiding and decoupling elements in the glass that can guide the incident light onto an image sensor - and thus turn any glass surface into a camera. This technology could eliminate the notch in smartphones. In large screens, on the other hand, such a camera could be integrated centrally so that participants in video conferences can look each other directly in the eye. According to Zeiss, the display quality of a display modified in this way should not be impaired by a holocam.
Many functions can also be implemented without a dedicated display using overlaid holographic elements. For example, these could be operating elements such as switches or controls on a window, which then becomes a kind of screen.
With special holographic coupling elements, a window could even become a light source that can illuminate a room and even simulate daylight. And a holocam sensor could also record "spectral components" to measure incident ultraviolet radiation, for example.
If even windows soon become multifunctional and can even film, the future has probably begun.
;)