So you're looking to upgrade your TV...
Just how much bigger is that new set going to be?
Is it going to be noticeable? Will it be too big?
Use our handy tool to find out!
Enter information about your current TV in the box on the left.
If you don't have all the information, that's OK - just enter what you have.
On the right, enter what information you have about the TV you're interested in.
Sample comparison of 35" traditional TV and a 40" wide-screen.
TV Measurements
Diagonal Dimension (Measurement)
The size of most televisions is given in terms of the "diagonal" measurement of the screen.
A "37 inch TV" measures 37 inches from one corner to the opposite (diagonal) corner.
This makes sense because it provides a consistent comparison of screen area regardless of screen shape.
In LCD and plasma televisions this measurement is made from the corners of the display area.
In older CRT televisions this measurement is often taken from the corners of the cathode-ray tube.
This can be misleading because it is usually bigger than the actual viewable area.
The specifications for some televisions will include a "viewable area" as well as the regular diagonal measurement.
Aspect Ratio
"Aspect ratio" refers to the relationship (or "ratio") of the width and height of the display.
Traditional televisions have an aspect ratio of 4:3. Which means that they are 3/4ths as tall as they are wide.
Newer LCD and plasma televisions are often considered "widescreen." These wider screens usually have an aspect ratio of 16:9 ("Sixteen by nine").
One of the main purposes of the comparison tool on this website is to allow you to meaningfully compare the visual area of screens with different aspect ratios.
When viewing wide-screen content on a 4:3 television, the material will often be "letterboxed" which reduces the visual height of the content in order to show the entire image on the screen.
Learn more about Aspect Ratios, mattes, and letterboxing at widescreen.org.
4:3 Aspect Ratio Screen
16:9 Aspect Ratio Screen
Types of Television Displays
CRT ("Cathode Ray Tube")
This is the type of display used in traditional televisions. The name refers to the large glass tube that makes up the screen.
CRTs work by illuminating dots of phosphor on the screen by firing a beam of electrons from the back of the tube.
Image Courtesy Søren Peo Pedersen
At the rear of the tube, there is an emitter. This emitter sends a beam of electrons towards the screen at the front of the tube.
The beam of electrons passes through a magnetic field which aims it at specific points on the screen at the front of the tube.
The screen at the front of the tube is coated with phosphor that glows when struck by the electron beam.
The phosphor dots are arranged in small groups of red, green and blue. By combining these three primary colors any color can be created.
- viewing angle
- Because the glowing dots are near the surface of the glass, each dot will be equally bright from any viewing angle.
- color fidelity
- Because each dot is self-illuminating, there are no issues with uneven lighting or viewing angles which would cause color variations across the surface of the screen.
- No "dead pixels"
- Since the process of laying down the phosphor dots is quite simple, CRT's don't suffer from the problem of "dead pixels" that effect Plasma and LCD displays.
- Weight
- As a CRT screen gets larger, the glass must get thicker to withstand the pressure of the vacuum inside. This can easily result in televisions weighing hundreds of pounds.
- Burn-in (Phosphor Burn-in)
- The phosphor compounds which create the actual visible light in the display become less luminous with use. This is one of the reasons old television sets look dim. If the display consistently shows the same image for long periods of time, that image can get "burned in" to the screen and appear as a darkened image whenever the display is on. This is most commonly an issue when the display is connected to a computer where common screen elements such as menus or windows may remain on the screen for long periods of time.
While new sets use a number of techniques to drastically reduce the occurrence of burn-in, the overall brightness of the display will diminish over time. - Size
- CRT displays are limited to around 45 inches. They also are deeper than most other displays since the electron gun must be placed far enough behind the screen that the entire surface can be hit by the electron gun. Traditionally, the electron gun had a sweep angle of 90 degrees. In the late 1990's many CRTs started using electron guns with a 100 degree arc, which allowed the tubes to be shorter.
What to Look For:
Most CRT ("Tube") Televisions will not be able to play HD ("High Definition") content. If you are interested in HD, look for these features:
| HDMI Inputs | New devices such as Blu-Ray players use HDMI connectors. |
|---|---|
| 16:9 aspect ratio | High-Def content will often be in the wide-screen format. |
| Digital Cable Ready | If you plan to use your new television with high-definition cable, you probably want a built-in "Digital Cable Ready" tuner. |
LCD ("Liquid Crystal Display")
The liquid crystal display works by shining a constant, pure white light through a liquid crystal "shutter" and then through a colored filter to create each dot (pixel) on the display. Each pixel is actually made up of three of these dots, one each of red, green, and blue.
The liquid crystal "shutters" work by first polarizing the light in one direction, then passing it through a layer of liquid crystal.
The liquid crystals rotate the polarization of the light passing through when current is applied. By varying the current, the amount of rotation can be controlled.
The light then passes through a color filter to remove the other components of the white light, leaving only the desired color.
The colored (and polarized) light now passes through a final polarized filter that is rotated 90 degrees from the original polarizing filter. If the light was not rotated, then no light will pass through the second polarizing filter and the dot will be dark.
If the light was fully rotated, then it will pass through the filter at maximum intensity.
The advantages of a liquid crystal display are:
- Flat
- because there is no large tube involved, the LCD can be much thinner than a display with a tube.
- Lightweight
- because it only requires a light source and the lightweight LCD shutters the liquid crystal display can be much lighter than traditional tube displays.
- Low Power Consumption
- Although the light source must always run at maximum power over the entire surface of the display, LCDs generally require less energy to run than CRT displays and much less energy than Plasma displays. LCD displays that use LED backlights use less energy than any other display.
- Viewing Angle
Because the color filters and liquid crystals sit between the viewer and the light source,
each pixel on an LCD display exists in a small "box" that prevents light from bleeding from one pixel to the next.
The "walls" of these boxes can block the line-of-sight between the light source and the viewer when viewed at an angle, reducing the perceived brightness of that pixel.
Newer and more expensive displays use shallower boxes to minimize this issue.
- Response Time
- Traditionally, LCD displays have been plagued by slow response times, since the liquid crystals take some time to change state. This results in "blurring" or "streaking" in fast-moving images.
Newer models do not suffer from this display "lag" as much, but be sure to check the specs for any model you are considering.
If considering an older LCD model or a very inexpensive unit, make sure to check the response time. Avoid anything over 8 milliseconds.
An excellent article on LCD response time can be found at Practical Home Theater Guide - Color fidelity
- LCD displays use a single light source that must illuminate each pixel in the display evenly.
It can be very difficult to manufacture a light source which is evenly lit across its entire surface.
Inexpensive LCD displays will often have uneven lighting across the display. In addition, on large displays, the viewer's angle from the display can vary quite a bit from the center to the edges of the screen. Because of this the pixels near the edges may appear darker because they are not being viewed head-on. - Contrast
- Because the light source is always "on" behind each dot of an LCD, it's difficult to completely block the light at a given pixel and achieve a true black.
What to Look For:
LCD TVs are a very popular choice. Check these specs on any TV your are considering:
| Response Time | Lower is better. No more than 8 milliseconds |
|---|---|
| Contrast Ratio | Higher is better. At least 1,500:1. |
| Viewing Angle | Best to check this in person, but look for at least 160 degrees. |
| HDMI | You will want at least one HDMI connector for hooking up a Blu-Ray, up-converting DVD, HD Cable, or Satellite player. |
| Digital Cable Ready | If you plan to use your new television with high-definition cable, you probably want a built-in "Digital Cable Ready" tuner. |
| Dead Pixels | Check the manufacture's policy on "Dead Pixels." Some warranties won't cover dozens of dead pixels. |
Plasma
Color plasma screens work on a principal very similar to fluorescent lights. Each colored dot is actually a small cell of neon and xenon gas that can be individually turned on and off.
The name "plasma" comes from the fact that when current is applied to the gas it ionizes into a plasma.
In the original orange plasma displays, this glowing plasma was the color of the display. In modern color displays, the ultraviolet light given off by the plasma causes phosphor to glow much like a traditional CRT display.
- Brightness
- Plasma displays are some of the brightest available.
- Contrast
- Because they can be very bright, and because each dot can be turned off to be black, plasma displays can have very high contrast. However, the individual dots don't actually get "turned off" when dark: a small voltage is maintained so that it can be powered-up quickly. Without this small current, the dot would flicker on much like a fluorescent bulb.
Many older and some current inexpensive sets don't let the dot get all that dark, which diminishes the contrast. Also, older, used televisions may have dimmed, further reducing the contrast.
For best results, purchase a new, "name brand" plasma display.
- Burn-in ("Phosphor Burn-in," "Image Retention")
- The phosphor compounds which create the actual visible light in the display become less luminous with use. This is one of the reasons old television sets look dim. If the display consistently shows the same image for long periods of time, that image can get "burned in" to the screen and appear as a darkened image whenever the display is on. This is most commonly an issue when the display is connected to a computer where common screen elements such as menus or windows may remain on the screen for long periods of time.
While new sets use a number of techniques to drastically reduce the occurrence of burn-in, the overall brightness of the display will diminish over time.
What to Look For:
Plasmas are currently more expensive than similar LCD displays but offer superior color and brightness.
| HDTV | Some older plasmas will be labeled EDTV. This not the same as HDTV. If you plan to watch HD content, avoid the EDTVs. |
|---|---|
| Contrast Ratio | Higher is better. At least 2,000:1. |
| HDMI | You will want at least one HDMI connector for hooking up a Blu-Ray, up-converting DVD, HD Cable, or Satellite player. |
| Digital Cable Ready | If you plan to use your new television with high-definition cable, you probably want a built-in "Digital Cable Ready" tuner. |
Rear-Projection Television ("RPTV")
Like a traditional projector, rear-projection televisions use a bright light source and lens to shine an image on a screen. Unlike a regular projector, they shine this light from the back of the screen.
Rear-projection televisions usually use a mirror so that the projector is not directly behind the screen. This allows for a shorter cabinet depth.
Rear-projection televisions are much thicker than LCD or plasma displays (10-15 inches v.s. 2-4 inches) but much thinner than CRTs.
Because the projector is usually below the screen, rear-projection televisions usually sit directly on the floor and don't use a separate television stand. Because of this, and because of their thickness, they are not suitable for wall-mounting.
Advantages of Rear-Projection:
- Price
- Since the limiting factors on screen size are brightness of the projector and the weight of the enclosure, the cost of a rear-projection display doesn't increase very much as the screen gets larger. This makes them an excellent value for large screens. (Over 50 inches)
- Weight
- Because the screen does not need to be made of glass, rear-projection televisions will usually be much lighter than a similar LCD or plasma unit. The mirror still adds weight, but overall, rear-projections televisions will usually be the lightest option for a given size.
- Size
- As mentioned in the Price section, rear-projection televisions will often offer the largest screen available for a given price point.
- Size
- Compared to LCD and plasma displays where the enclosure is not much larger than the actual display, the cabinets of rear-projection displays appear bulky.
- Lamp Life/Cost
- The bulb in rear-projection televisions that use a traditional projector lamp will eventually burn out (1000-2000 hours of viewing). These bulbs are expensive, and may be annoying to replace.
Rear-projection televisions that use LED light sources don't have this issue. - Contrast
- Unless used in a completely darkened room, rear-projection displays will have better contrast then regular front-projection systems. This is because the reflective screen will reflect all the ambient room light as well as the intended image.
Older rear-projection systems suffered from poor contrast. Newer models feature advances in screen material and projection technologies that overcome these problems. - Bulk
- Rear-projection televisions appear much "bulkier" than similar plasma or LCD displays.
OLED (Organic LED)
OLED displays are thin, light, extremely bright, have outstanding contrast, and low power consumption.
So why aren't they more popular?
As of this writing (late 2008) they are VERY expensive ($2500 for an 11 inch model) and very small (no OLEDS larger then 15 inches are being manufactured.)
Projector ("Front Projection")
This is the true "Home Theater" experience.
The image is projected onto a screen, just like in a theater.