American inventor Gene Dolgoff started his first LCD projector design in 1968. In 1988 he started Projectorvision inc. Since this first LCD projector, the
technology has been evolving. Today Epson and Sony manufacture LCD panels. Over the last few years the latest LCD panels have been eagerly anticipation
by the industry, each new release producing higher resolutions, better contrast and the faster refresh rates.
LCD's are known to produce great colour definition, offering more shades or variations of colour. Add to this the superior brightness,
no Rainbow Effect and good portability and you'll know why LCD still remains the most a popular choice for presenters.
LCD Panels
In 2006 the manufacturer of DLP, Texas instruments, tested the durability on LCD panels by running the best Home Cinema
machines 24/7 for 3 months. At the end of this test they concluded that the Organic material used in LCD panel gets damaged from the UV
light and heat generated by the projector lamp. This results in discolouring of the panel to amber. This has led to the development
of inorganic LCD panels.
Light path through an 3LCD system
2006, Epson launches the D7 panel. Using
C2Fine Technology,
Incorporating a high temperature polysilicon LCD with an inorganic Vertical Alignment Nematic (VAN) liquid crystal mode. The technology enhance the contrast ratio and
reliability of 3LCD products, especially 1080p MD-TVs based on the technology. In fact, in the central position at the 3LCD booth at InfoComm was a 57-inch 1080p 3LCD
television prototype, the contrast ratio of which was said to be "more than 10,000:1."
The C2FIne panel also improved colour, with over 1.1 billion colours produced
This contrast ratio improvement over traditional 3LCD products comes from VAN's ability to "project" black when no voltage is applied to the pixel
space. In effect, black is VAN's natural state. 3LCD announced that it expects products with C2Fine technology to be available in 2006.
If it sounds similar to the BrightEra panel, Sony and Epson are both in the 3LCD alliance. Which developes 3LCD technology together.
Roll on 10 years, Sony take us into a BrightEra. With an inorganic alignment layer to protect the organics. BrightEra improved LCD durability up to if
not surpassing that of DLP. With the additional benifits of improved light efficiency, higher contrast and faster refresh rates.
Another benefit of Sony's inorganic alignment layer is dramatically more stable color rendition. Compared to previous 3LCD designs, BrightEra panels
produce a more consistent colour across the screen.
Conventional 3LCD panels display white in the absence of voltage, limiting contrast. BrightEra panels display black in the absence of voltage to deliver more than
three times the contrast. That's even prior to optical compensation, a technology that drives contrast higher still!
Laser Systems
Laser Phosphor Technology based on 3LCD Panel Technology
Laser Phosphor projectors use two blue lasers. One to create the blue colour in the final image, an the second to illuminate a yellow phosphor
wheel, which emits the yellow light. This yellow light is then split by a filter into green and red light components.
Blue laser based LCD projectors use three LCD panels to generate the red, green and blue picture part of the visualisation,
leading to vivid colour representation.
Cost-effective
Vivid colour representation
High brightness
Laser Phospher LCD projection system
Dynamic Iris
Iris control goes a very long way in resolving the contrast and black-level issues. In a camera, the iris controls the exposure in conjunction
with the shutter speed. In a projector, it changes the brightness of the image on the screen. If you close down the iris in a projector, it
darkens the overall image, including the darkest grays and deepest black. But the only type of iris that has been available to date in video
projectors has been fixed; multiple settings are often provided , but once you make a selection, the iris size remains unchanged unless you
manually adjust it.
Closing down such a manually adjustable iris will reduce the light levels in both the blacks and peak whites, but this isn't necessarily
a bad thing. Reducing the average picture level on the screen with the iris may improve the overall image by deepening the blacks, thereby
reducing the grayish, washed-out effect of an absolute black level that is too high, without sacrificing adequate punch in brighter scenes.
For this to work, of course, the light output of the projector must be high enough that the overall dimming effect of the stepped-down iris
is tolerable.
Advanced Iris dynamically adjusts the iris to suite the scene. That is, it closes down automatically on dark scenes to provide darker blacks,
and opens up on bright scenes to make optimum use of the projector's available light output. This has raised the contrast ratio to levels
never before seen on an LCD of 2000:1 to 12000:1.
Inorganic
The latest panels include an inorganic alignment film. These new LCD materials were developed to achieve the high picture quality and high
durability of the reflective LCOS type LCD projectors. Current high-brightness projectors generally use LCD materials that are advantageous
for increasing brightness, and the optimum organic alignment film (polyimide) for aligning these LCD materials. One thing to note is the
effect of panel size. Larger LCD panels are less prone to the deterioration because the UV light is spread over a larger surface area.
Industries highest refresh rate - 480Hz
When projecting 3D images or for gaming, Image brightness is greatly reduced 120Hz DLP machines can drop to 40% perceived brightness.
This is due to the switching from Left to right eye images. Increasing the refresh speed reduces this loss. The latest D9 LCD panels have
a refresh rate of 480Hz, 4 times DLP
How 480Hz projector works
Screen Door Effect
Once upon a time, it was widely accepted that LCD projectors had two major weaknesses. First, in commonly available consumer models,
the pixel structure could result in the infamous "screen door effect". That is, because the wiring driving each pixel had to be
routed between the pixels, the pixel spacing, or pitch, was wide enough to make the pixel grid visible at close viewing distances.
The picture below shows the screen door effect on the keys of a piano.
LCD Screen door effect pixel grid
While the picture above is an example of the screen door effect, still noticeable on LCD data projectors but greatly reduced by smooth
screen technology on the latest Home Cinema models. This issue has been over played by DLP manufacturers. To clarify all projector have the
screen door effect, including DLP. Yes to a lesser extent than LCD but for a mirror (used in DLP projection) to be able to move it must
have space around it in exactly the same way LCD requires wiring. The fill factor of a projector panel gives only an indication of the
potential screen door problem. Currently LCD panels have the lowest fill factor of 60%, DLPand LCOS (Dila, SXRD) have the highest at 93%.
The screen door difference between the technologies has also been reduced by the increase in panel resolution and larger LCD panels in home
cinema machines. Micro Lens Arrays have also been used to reduce the screen door and boost Lumens.
Projector and replacement lamp prices are in Aussie Dollars. They include GST and delivery, There are no hidden charges the price you see is the price you pay.
Prices and product availability can fluctuate and are subject to change without notice.
Projector and replacement lamp prices are in Aussie Dollars. They include GST and delivery, There are no hidden charges the price you see is the price you pay.
Prices and product availability can fluctuate and are subject to change without notice.
