María Valladares Álvarez
This final report is aimed at presenting two new technologies in flat panel display: The
LCD (Liquid Crystal Display) and the Plasma display. This final essay is the last requirement for the course Computing Architectures and Environments – CST 337, taking by the student during the Spring semester of 2002 at the California State
University, Monterey Bay. In this course, the student has learned about the components of a computer; by completing this report, she has had the opportunity to explore and learn more about these new technologies. To do the following report the student has reviewed the materials of the course, and has searched for and identified relevant materials on the topic in the Internet.
CST 337: Computing Architectures and Environments
Instructor: Doug MacIntire
It seemed like science fiction, when my brother in law bought his first flat screen to see his favorites TV programs lying on his bed. It was a huge flat screen! That happened not that long ago, perhaps 4 years ago. Today this technological advance is no longer science fiction; it is fairly normal to see flat screens in many different appliances, computers, and
TVs for the most part. I am even looking at these pages on my flat LCD (Liquid Crystal
Display) monitor at home. I was interested in this topic, perhaps because I wanted to know more about what I had and what was new in terms of technology in the market. I wanted to know why LCD could cost two to three times as much as traditional CRT
(Cathode Ray Tube). Monitors cost is an issue, so there should be a reason why I had a
LCD, other wise I would have to stick with a CRT. During my navigation through the
Internet I learned about the Plasma display; then, I was interested in knowing the difference between this, and the LCD display.
This report has five different sections. First section explains how LCD works, then how Plasma Display work, and some of the applications of these technologies. A third section will explore some studies done by plasmapeople.com and the PC Magazine that the student found very interesting. The four section is dedicated to the pricing of these technologies. In the last section the reader can find how CRT are still competitive even though these technologies are offering so many features.
How LCD works
The course’s web site materials present an explanation on how LCD works. A normal passive matrix LCD comprises a number of layers. The first is a sheet of glass coated with a transparent metal oxide. This works as a grid allowing the current pass to activate the screen elements. Then, an alignment layer will align the liquid crystal molecules in the appropriate direction and this is repeated on another glass plate.
After that, there is polarizing layers that will match the orientation of the alignment layers. The light that passes through the layer will create the image on the screen. This works without applying power. If voltage is applied, then the light won’t pass.
But LCD response itself is very slow, and this can lead to a ghosting effect, that is perceiving by the viewer as if the eye is trying to focus. The response time in an area that need improvement. The pixel response on a CRT is nearly instantaneous; if the image weren't refreshed often enough, you'd see a flicker as it faded before the next time it was painted on the screen. By contrast, the liquid crystal material inside the LCD cells must physically move from one position to another in order to block or transmit light. This takes much longer to accomplish and results in that blurring. How Plasma Display works
Alfred Poor, a contributing editor of PC Magazine, explains how
Plasma Display works, in an article of the mentioned magazine.