Woodman, why LCD&DLP-based RPTVs can not do 1080i HD resolution?

[Smokey]

As you said, LCD and DLP based RPTVs can only do native 720 progressive (1280x720 pixels)* HD signal only, and are not capable of displaying native HD 1080i (1920X1080 pixels)**. But CRT-base RPTV can do 1080i native HD signal.

Is "fixed" pixels the limiting factor for LCD&DLP displays, or is it some other reasons?

* 1280 pixels horizontally, and 720 scan lines vertically.
** 1920 pixels horizontally, and 1080 scan lines vertically.

[woodman]

My dear, dear Smokey-san:
First off, 1080i is not a "resolution" ... it's a scanning format, as is 720p, 480p, 480i, etc. They are all scanning formats, that's all. NOT "resolutions".

The question of what "fixed-pixel" displays are capable of in terms of "resolution" is indeed based upon the number of available pixels to display the image. In the case of LCD and DLP products the number of pixels maxes out at less than a million. CRT-based display products have roughly double that number.

The LCD, DLP, and plasma displays can accept 1080i signals, but must down-convert them to what their native pixel array can show.

[AVMASTER]

Is "fixed" pixels the limiting factor for LCD&DLP displays, or is it some other reasons?

the main limiting factor is how well they can convert the higher format, i.e. take a look at a Gateway PDP vs a Panasonic, a Panasonic PLCD vs a Hitachi or a Optoma DLP projector vs a Vidikron

[Fallen Kell]

The fixed number of pixels is the limiting factor (that and the manufacturing process which is very expensive to place more pixels on screen). There will be some issues with the downconverting of the signal and you can wind up with some jagged edges in colors, etc., but that is just the nature of the beast of downconverting. Because the pixels are fixed in size and number, it is impossible to downconvert the signal without some serious color perception matching on the pixels. Since you will wind up with 2 pixels from the higher definition source being converted to fit in the space of 1 pixel in some cases, it is hard to say what color to give that pixel if one of the colors being displayed is supposed to be bright blue, and the other is suppose to be bright yellow for instance. This is why it will not look as good as when using a native signal of the correct resolution...

[Smokey]

Thanks everybody. Great information as always.

To me, if a monitor can not display native 1080i (which is the most popular format), it makes them a "second class" HD monitor. But I am sure that shortcoming have to be eventually addressed if CRT based displays are to be phased out.