|
|
CRT Displays
|
LCD Displays
|
|
Resolution
|
Operate at any resolution, geometry and aspect ratio without the need
for rescaling the image.
Run at the highest pixel resolutions generally available.
|
Each panel has a fixed pixel resolution format determined at the time of manufacturer that can not be changed.
All other resolutions require rescaling, which generally results in
significant image degradation, particularly for fine text and graphics.
|
|
Sharpness
|
The CRT beam produces images with softer edges that are not as sharp
as an LCD at its native resolution.
Imperfect focus and color registration also reduce sharpness.
Generally sharper than LCDs at other than native resolutions.
|
Image is perfectly sharp at the native resolution of the panel.
All other resolutions require rescaling, which generally results in
significant image degradation.
If you need fine text and graphics at more than one resolution do
not get an LCD display.
|
|
Interference
|
All color CRTs produce annoying Moiré patterns.
Many monitors include Moiré reduction, which normally doesn't
eliminate the Moiré interference patterns entirely.
|
LCDs using an analog input require careful adjustment of pixel tracking/phase
in order to reduce or eliminate digital noise in the image.
Automatic pixel tracking/phase controls seldom produce the optimum setting.
Timing drift and jitter may require frequent readjustments during the day.
For some displays and video boards you may not be able
to entirely eliminate the digital noise.
|
|
Geometric Distortion
|
Subject to geometric distortion.
Most CRTs have user controls that can reduce or eliminate the distortion.
The more controls available the less distortion you're likely to see.
|
Zero geometric distortion at the native resolution of the panel.
Minor distortion for other resolutions because the images must be rescaled.
|
|
Aspect Ratio
|
Can easily reproduce any desired aspect ratio.
|
Have a fixed resolution and aspect ratio.
For panels with a resolution of 1280x1024, the screen aspect ratio is
5:4=1.25 which is noticeably smaller than the 4:3=1.33 aspect ratio
for almost all other standard display modes. For some applications may
require switching to a letterboxed 1280x960, which has a 4:3 aspect ratio.
|
|
Black-Level
|
Produce a very dark black. Suitable for use even in dimly lit
and dark environments.
|
Have difficulty producing black and very dark grays.
Not suitable for use in dimly lit and dark environments.
|
|
White Saturation
|
Bright-end of the intensity scale is very rugged and seldom results in
saturation and compression.
|
Bright-end of the intensity scale is easily overloaded, which leads to
saturation and compression.
When this happens the maximum brightness occurs before reaching the peak
of the gray-scale or the brightness increases slowly near the maximum.
Requires careful adjustment of the Contrast control.
|
|
Brightness
|
Relatively bright but not as bright as LCDs.
Not suitable for very brightly lit environments.
|
High peak intensity produces very bright images.
Best for brightly lit environments.
|
|
Contrast
|
Produce the highest contrast levels normally available.
|
Lower contrast than CRTs due to a poor black-level.
Don't believe the published contrast ratios.
Real world operational values are substantially lower.
|
|
Gray-Scale
|
Have a perfectly smooth gray-scale with an infinite number of
intensity levels.
|
Have an irregular intensity scale and typically produce fewer
than 256 discrete intensity levels.
For some LCDs portions of the gray-scale may be dithered.
|
Gamma
shape of the gray-scale
|
CRTs have a natural power-law Gamma.
Values may vary from 2.2 to 2.5, but are still close to a perfect power-law,
which is assumed in virtually all professional color
and gray-scale calibrations.
|
The internal Gamma of the panel is very irregular.
Special circuitry attempts to fix it,
often with only limited success.
Affects the accuracy of the gray-scale and color mixtures.
|
|
Color and Gray-Scale Accuracy
|
The reference standard, the very best color and gray-scale.
If you need very accurate color and gray-scale calibration then get a CRT.
|
Pleasing images but not accurate because of problems with black-level,
gray-scale and Gamma.
Reduced color saturation at low intensity levels due to a poor black-level.
Generally not suitable for professional image color balancing.
|
|
Bad Pixels
|
In rare instances 1 or 2 dark phosphor dots, which are hard to detect.
Aperture grille tubes generally have 2 very thin wires that are sometimes
noticeable. Bothers some people but most don't notice.
|
Can have many weak or stuck pixels, which are permanently on or off.
Some pixels may be improperly connected to adjoining pixels, rows or columns.
|
|
Viewing Angle
|
Can be accurately and comfortably viewed from a very wide range of positions
and angles.
|
Limited viewing angle.
Brightness, contrast, gamma and color mixtures vary with the viewing angle.
Can lead to contrast and color reversal at large angles.
Need to be viewed as close to straight ahead as possible.
|
|
Motion Artifacts
|
Have fast response times and no motion artifacts.
Best for rapidly moving or changing images.
|
Slow response times and scan rate conversion result in severe motion artifacts
and image degradation for moving or rapidly changing images.
|
|
Screen Shape
|
Some CRTs have a rounded spherical or cylindrical shape screen.
Newer CRTs are flat.
|
Screens are perfectly flat.
|
|
Emissions
|
Give off electric, magnetic and electromagnetic fields.
There is considerable controversy as to whether any of these pose
a health hazard, particularly magnetic fields.
The most authoritative scientific studies conclude that they are not
harmful but some people remain unconvinced.
|
Produce significantly lower electric, magnetic and electromagnetic fields
than CRTs.
|
|
Cost
|
Less expensive than comparable displays using other display technologies.
|
Considerably more expensive than comparable CRTs.
|
|
Physical
|
Large, heavy and bulky.
Consume a lot of electricity and produce a lot of heat.
|
Thin, with a small foot print.
Consume little electricity and produce little heat.
|
