A lot of modern sets will be labeled with a size class, such as the "43-inch class" or "65-inch class" which means "it's within about a half inch." So a 55-inch class set could actually be 54.68 inches. Kinda like how Hard Drives are designed in powers-of-two ("Gibibytes") but marketed in powers-of-ten ("Gigabytes") so that you wind up with less storage in practice than you thought you paid for.
Resolution is probably the metric you're most familiar with, and certainly one of the easiest to understand, although it's evolved some of the most confusing terminology. Simply put, resolution is the number of pixels (or discrete units of visual space) on the display. Since we're all grown-ups here, I'll ignore anything less than "high definition."
Aspect Ratio: All current high definition ("HD") standards are a
16:9 apsect ratio, which is a comparison of the width of the screen to its height. In other words, if you divide the width by the height, it will always equal
The "p": All HD screens are defined by the number of horizontal lines of progressive scanning required for rendering. So, 720p means the display is 720 pixels in height (and since HD is defined as
16:9, this means it is 1280 pixels wide).
The "K": While "p" designators refer to the number of horizontal pixel rows, the "-K" suffix refers to the approximate number of vertical pixel rows on the display, in thousands. So a 2K display is roughly 2,000 pixels wide. A 4K display is roughly 4,000 pixels wide.
The "HD": All HD screens can be defined by a *HD label. For example, 720p is defined as "HD" (so they mean the same thing). 1080p is defined as Full High Definition (FHD). If you see "_HD" (and it's labeled truthfully) you're looking at a
In short, "-p," "-K," and "-HD" can all be used interchangeably, and specifying any two at once is redundantly redundant, although you'll be hard pressed to find a "2160p TV" because "2160p 4K UHD TV" offers much better marketing juice - it has more numbers and acronyms, therefore is a better product.
LCD: The mainstay of flat-panel display technology, although losing market share to LED. LCD stands for Liquid Crystal Display and they're a great general purpose screen, but aren't considered the best in any meaningful metrics. A traditional LCD screen is either backl-it or edge-lit (using what's called a CCFL - a cold cathode fluorescent lamp), meaning that the light comes either from behind the screen, or the sides. The LCD technology itself controls how that light is reflected to produce a picture.
Plasma: Relatively power hungry but brilliant and crisp, plasma screens offer among the blackest blacks and sharpests contrasts. The sharpness and viewing angle of the plasma display is considered superior, but it comes at a cost: plasma TVs are typically heavier, consume more electricity, and are more susceptible to burn-in (where displaying a static image for long periods of time can irreversibly damage the display).
LED: Light Emitting Diode ("LED") displays are thinner, lighter, brighter, and more power efficient than LCD and Plasmas. They could more accurately be called LED/LCD, because the display technology is actually the same as LCD. It's the lighting that's different — instead of a CCFL, LED/LCD displays use (go figure) LEDs to backlight the display. The choice of LED over CCFL yields all the advantages mentioned, at the expense of... well, expense. LED sets are more costly on average than CCFL sets.
(In common use, they're typically just called "LED" TVs — only RMS would actually call them "LED/LCD" TVs. Holler if you get the joke.)
OLED: OLED (Organic Light Emitting Diode) displays generate their picture without backlighting. That is to say, both the light AND the picture come from the the same source (the diodes). This makes for lighter, thinner, flexible, and more power efficient displays than LEDs and provides wider viewing angles. The blacks produced are the purest possible, and the response time is orders of magnitude faster than LCD technology. Problem is, at the time of writing, they're a lot more expensive and there's healthy evidence to suggest they simply don't age well.
Not much to say here, except that higher is better — and more expensive. Most common TV sets refresh at 60Hz (60 hertz means 60 times per second) but higher refresh rate sets are also available, which provide for diminished motion blur and thus potentially a clearer picture. 120Hz and 240Hz aren't too tough to find, although the difference is subjective.
Simply put, an LCD screen (CCFL or LED) with IPS boasts a wider viewing angle as well as a higher price tag. A worthwhile expense, depending on the use case.
Smart TV: Think of a Smart TV as a television set with the intelligence of a smartphone, but the common sense of a rock. A dull rock. With moss on it. Typically, the big upsell on Smart TVs is that they're able to load applications. For example, you could browse Facebook or watch Netflix videos straight from your TV. If you have anything which can already load up streaming apps (such as a Roku, Apple TV, modern video game console like the XBox or Playstation), then a Smart TV offers nothing of value other than a higher sticker price, pointless complexity, and a massive, obscene, hilarious, ghastly and neglectful array of various vulnerabilities. Seriously, you don't want one of these catastrophes-waiting-for-a-time-to-happen sitting on your network.
Curved TV: Name says it all. When your TV is too big and/or you're sitting too close, curving the glass inward helps you to take in the whole big picture at once. And you're gonna pay royally for it.
3D: Again, name says it all. If you want to pay extra for the privilege of wearing dorky glasses for an experience that wouldn't fool a toddler, you have the freedom to make that choice for yourself.
Now that we're all caught up to speed, I'll get back to my original point, which is that I want a display with high enough quality that when Daniel Craig fires his gun, I should be able to pause the movie and read which brand of ammunition he prefers from the bottom of the cartridge case.
Problem is, my living room isn't huge. Realistically there's just not a permutation of our furniture that permits a 43- or 55-inch class display. So, I want quality. I want a 4K OLED at 240Hz, preferably non-smart. But I also need something not topping 40 inches (38 is about the limit for the space). Problem is? That's a unicorn. There is no "middle" in the current TV market. There aren't many, if any, television sets with quality specs but at a modest size. Even if I loosened my requirements to simply "4K under 40 inches" there's just not enough competition there to give me confidence buying.
All in all, I wound up low-balling. A 32-inch 1080p @ 120Hz. For now, I'll have to be satisfied with nominal levels of grainy loss and back-lit diffusion animated by the disapproving frowns of friends and relatives who, coming to visit, will recognize my lack of dedication and convey the weight of my failure with a sullen stare, framed by furrowed brows and seasoned with a disappointed sigh.