Display Tech

As with modern day, the large amounts of data and information need to be displayed to a user. While there are methods to directly relay information to a user's mind, screens and the like are the most popular. There are three main types of these; regular screens, screenglass, and holograms.

Screens

Screens are roughly the same as today. In fact, they are nearly the same in terms of quality. They're used to display all sorts of stuff, from information to video games to just plain colours. Digital screen technology has not advanced particularily much over the last 900 years, but works just fine. They're simple, reliable, and efficient, and so see use in just about everywhere, from warships to personal computers. Transparent screens are also included in this category, and are used here and there.

Screenglass

The name "screenglass" is somewhat inaccurate, as transparent screens fall under regular screens. Screenglass is essentially what one gets when one takes a wall, be that a starship hull or just a wall, places a grid of cameras on one side, and a grid of screens on the other. When these cameras are properly placed and oriented, and the screens focused towards one point, the final effect is that of a seemingly transparent wall. Looking at the view from other angles than the intended one skews the view somewhat, but this method is still useful. Screenglass is particularily common on starships, especially military ones, as it allows a good view of a situation without needing weakpoints like windows. The screens being, well, screens also allows information like nearby ship and habitat positions or other important locations to be displayed on it. A starship's bridge often has a dome of sorts made of screenglass, wherein the captain can observe the area around them, as the picture at the bottom features.

Holograms

Holograms are the rarest of the three main display methods. Their complexity and price are why they're not too common, but they have quite a few uses. For the most part, they display scenes and situations a 2-dimensional display would be less suited to, like fleet formations or a starship's general status and details. A captain might, for example, have a hologram of the habitat the ship's approaching displayed to see details of it, where to dock for example.
Holograms are contained within a glass tube of sorts, filled with a gas commonly referred to as holo-gas. At the top and bottom of a hologram setup are the projectors. These are lined with a tight grid of emitters. They emit certain wavelengths of light toward the respective emitter. When these beams collide, they release an amount of radiation, which turns into a small amount of light, which spreads into every direction, when interacting with the holo-gas. Where in the collision of the two beams the light-producing reaction happens depends on the relative frequencies of the two beams. This being the case, having two points lit up in the same vertical beam sounds impossible. And technically speaking, it is, but the beam frequencies can be changed fast enough to have it appear as though there are two points on a beam. Of course, this means that the more points there are on an individual line, the less defined and more transparent and flicker-y they get.
Holo-gas is constantly burnt up when a hologram is operational, but at a slow rate, and holo-gas is easily replenished by any ship with decent manufacturing capability.

Availability

Screens are the most common display type by far. They're available just about everywhere, and every mid-size assembler can make one, if it has the right materials on hand. Screenglass is somewhat less so, though the technology to make it is also availably nearly everywhere. It's not as common mainly due to niche use it has, but within that niche, being starships, it's ubiquitous. Holograms are not common. While they're not very high-tech anymore, they are mainly limited by size and complexity, in less advanced regions at least. A hologram setup usually has a large system supporting it, and is often only installed onto large ships, often no smaller than a kilometer or so. In the Core Worlds and similarily advanced regions though, the tech has advanced enough that that is no longer as much of an issue, and holograms have been fitted onto ships as small as cislunar personal civilian craft.

History

Screens have been around since modern day, and have remained remarkably similar. No significant advances in display quality or refresh rate have been made, though most screens are more durable than today. Screenglass has been around since the early 2100s, and is one of the oldest and most common such methods of simulating windows on a starship. Holograms are not new either, having been invented in the 2400s, but are still uncommon enough to be considered a novelty of sorts, excluding those who work aboard large ships at least.

The bridge of the Stalwart Sentinel, utilizing both conventional screens and a large view by screenglass.

Bridge of the Stalwart Sentinel by MadToxin

Hologram Diagram by MadToxin

A display of the specifics of how a hologram works

1. The laser beams are emitted toward each other. Each is a certain, different wavelength to the other, and their frequencies vary based on what is needed.
2. The beams collide, releasing radiation.
3. The higher-frequency beam goes further along the distance, pushing the other beam back. How far depends on the relative frequencies, and is how the positions of the hologram's "pixels" are determined. While the beams are pushing to the position, they trigger the light-releasing effect before settling into a good position, making a thin, brief line to it.
4. The beams settle into place. This place is where the "pixel" is on the hologram. Each shape and component in the hologram is composed of these collision points.
5. The beam collision releases a type of short-lived radiation, which goes out into all directions. It doesn't last long, but enough to interact with nearby holo-gas compounds.
6. The radiation reacts with the compound that composes holo-gas. This releases light in all directions, forming a "pixel" in the hologram. This lasts for as long as the beams are colliding, assuming there is enough holo-gas. Though since the gas is used up slowly, and circulates around the hologram chamber, it lasts for a long while. A reasonably detailed hologram can be kept up for weeks at a time.