LCD and DLP: Combining tech?

[WriteSimply]

I've heard that SXRD/D-ILA tech are not ideal when dealing with starry nights - - deep blacks but not enough brightness to the stars. This is caused by the auto-iris which reduces the light that shines through the LCD panel. The same iris however makes the SXRD/D-ILA have a better contrast ratio than LCD projectors/RPTVs.

I know that single-chip DLP projectors/RPTVs, which is what normal people would have, have the problem with the rainbow. Specifically because DLP has no color mirrors, color wheels have to be applied to make the color appear. DLP however does have a high contrast ratio and does so without the auto-iris.

Now we have CEs developing new display technology based on these two chips but using lasers. My understanding of lasers is that apart from being bright, they can burn the cones and rods in your eyes. So while laser LCDs/DLP techs are coming soon this fall, I think it's best if somebody else get blinded first.

So here's my suggestion to an alternative future tech of projectors/RPTVs. Combine both LCD and DLP chips into a single system. Working with a new algorithm, this will hypothetically deliver a colorful and brighter picture.

The video signal is divided into chroma (color) and luma (luma) signals, which is somewhat similar to how DLP works, except that the color wheel creates a chroma and luma signal per wheel segment. The chroma signal is delivered to the LCD chip while the luma signal is delivered to the DLP chip. The LCD sits on top of the DLP chip because light HAS to be bounced off the DLP chip.

This combination of LCD and DLP solves all the problems of either technology while harvesting the advantages of both to the maximum. High contrast ratio and great color rendition without the rainbow effect (new faster LCDs to reduce ghosting must be used) can now be achieved by using conventional bulbs. With a little bit of refinement, I believe this combination of technologies can be developed very quickly for the target market of home users.


fuad

[Blackraven]

OLED will beat both current LCD (regardless of CCFL or LED backlight) and DLP on tech specs.

In the line of contrast ratios, response time and power consumption, even combining LCD tech and DLP would not be enough to make a dent on OLED.

LCD tech needs to advance further (blacks are not even as deep as plasma TVs) and DLP-powered RPTVs have FAT ASSES. Heck, even Sony is thinking of using Laser TV tech for use in their SXRD line to shave the rear-end of its RPTV sets.

So for the next decade, it's up to OLED TV and Laser TV to do the job

[WriteSimply]

Originally Posted by Blackraven

So for the next decade, it's up to OLED TV and Laser TV to do the job

But you can't get OLED or LaserHDTV 50"" below US$4000 in the next 2 years.


fuad

[Deciazulado]

Well I think having 2x technologies (DLP -> LCD, or even LCD -> LCD) to increase on/off contrast, though a logical idea on concept, would be costly to implement. Apart from the double-expense components, there's new optical paths to be redesigned too, and in the end, lens and optical flare might make ANSI contrast be similar or even worse than before.

[Ascended_Saiyan]

LCD panel laid on top of a mirror or mirror-like surface? That sounds like LCoS to me.

[Deciazulado]

Quite, but not exactly, WriteSimply meant one light modulator modulated by the light output of another light modulator so you have more on/off contrast and improved color. A simple enough idea (c) fuad and deci but not as simple to implement effectively in practice

flare is the light killer. flare is the little deci that brings total obliteration.
I will face my flare. I will permit it to pass over me and through me.
And when it has gone past I will turn the light meter to see its path.
Where the flare has gone there will be nothing.
Only light will remain. - Blu-Bene Gesserits

[WriteSimply]

Originally Posted by Deciazulado

A simple enough idea (c) fuad and deci

I think flare can be minimized. The main issue for me is fill-ratio. I don't know what the ratio will be if these two techs are combined.


fuad

[Deciazulado]

Well if you're aiming the micromirror bounced pixels back at the LCD's pixel "cells" it would either have to be very precise, or the LCD have small fill ratio (big black borders) kind of like an aperture mask grille and phosphours on a CRT so the "beams" hit the center of the LCD pixels. mmm.. maybe laser precision?

[nhaase]

Since the laser is being projected to the screen, and not your eye, you won't have to worry about it burning your retinas. I don't think the FCC would approve of this (sarcastic w/ the "think"), so don't worry about that.

[takezo]

Originally Posted by WriteSimply

I've heard that SXRD/D-ILA tech are not ideal when dealing with starry nights - - deep blacks but not enough brightness to the stars. This is caused by the auto-iris which reduces the light that shines through the LCD panel. The same iris however makes the SXRD/D-ILA have a better contrast ratio than LCD projectors/RPTVs.

I know that single-chip DLP projectors/RPTVs, which is what normal people would have, have the problem with the rainbow. Specifically because DLP has no color mirrors, color wheels have to be applied to make the color appear. DLP however does have a high contrast ratio and does so without the auto-iris.

Now we have CEs developing new display technology based on these two chips but using lasers. My understanding of lasers is that apart from being bright, they can burn the cones and rods in your eyes. So while laser LCDs/DLP techs are coming soon this fall, I think it's best if somebody else get blinded first.

So here's my suggestion to an alternative future tech of projectors/RPTVs. Combine both LCD and DLP chips into a single system. Working with a new algorithm, this will hypothetically deliver a colorful and brighter picture.

The video signal is divided into chroma (color) and luma (luma) signals, which is somewhat similar to how DLP works, except that the color wheel creates a chroma and luma signal per wheel segment. The chroma signal is delivered to the LCD chip while the luma signal is delivered to the DLP chip. The LCD sits on top of the DLP chip because light HAS to be bounced off the DLP chip.

This combination of LCD and DLP solves all the problems of either technology while harvesting the advantages of both to the maximum. High contrast ratio and great color rendition without the rainbow effect (new faster LCDs to reduce ghosting must be used) can now be achieved by using conventional bulbs. With a little bit of refinement, I believe this combination of technologies can be developed very quickly for the target market of home users.


fuad

Light Bounce of the DLP chip? Don't DLP use tiny little mirrors to progect the image off a DMD chip matrix?

Light can't be seperated into lumanance (brightness) and Croma (color element). Light can only be seperated into 3 primary prism colors. These colors form a dot on the screen called a pixel (picture element), the color of the pixel determined by the level of luma and croma.

Croma And Luma are video signals that travel through a physical media, such as component or coaxil cables, which is then processed by the video chip in your TV, into electrical signals which interact with the DMD matrix and backlight.

According to wikipedia, there are two types of DMD. Single Color wheel, or Tri-color wheel. Single color wheels using old lamp style back lights are known to have Rainbow effects, Though newer Single Wheel are now using LED back lights (which you could put 3 colored ones) which improve color, and eliminated the rainbow effect to exception of a few sensitive veiwers.

Tri Wheel almost works like a CRT but instead of three color cathode ray guns shooting a phosphor laden tube screen, it has three color wheel reflecting prism light to be projected on to the screen.

Rear projection TV's based off LCD have been already made.

I really don't know how LCD technology can be used injunction with DLP.

[WriteSimply]

Originally Posted by takezo

Light Bounce of the DLP chip? Don't DLP use tiny little mirrors to progect the image off a DMD chip matrix?
...
I really don't know how LCD technology can be used injunction with DLP.

LCDs projectors and RPTVs use color LCDs. They create an image and Light passes through them. Look at a laptop screen and that's exactly how it works, just that for projectors/RPTVs the LCDs are much smaller.

DLP uses DMD (Digital Micro Mirror) technology. In itself DMD chips do not have color as they are just that - mirrors. If you have a light source and you feed a signal off a DMD, all you get is a black and white video.

In a 3-chip DMD projector (high end stuff mostly for Digital Cinema projection systems), three light source - Red, Green and Blue - are used to bounce off the DMDs and make one image. Before that is done, the video signal is divided into each of its chroma signals and each of the signals are fed to the corresponding RGB DMDs. The luma is by design automatically handled by the DMD, as each micro mirror handles how much light it reflects.

In a single-chip DMD projector/RPTV, the video signal is divided into RGB, Clear and Dark, and grey in some setups, I believe. This signal is then fed to the DMD while the color wheel that corresponds to the signal is flashed before the light source. The rapid spinning of the wheel and the change of the DMD signal creates the full color effect. However this approach leads to the rainbow effect.

My approach is simple, in theory. Split the signal into chroma (or chroma and half a luma) for the LCD chip while the luma is handled by the DMD chip. This way the colors pop and the contrast ratio on any given scene is high.


fuad