LASER, LED Projector Systems
Firstly we would like to clarify,
Projectisle believe in giving you the information you need to select the best
projector for your requirements. We do not want to sell you an item that will
not perform as expected. Every now and then there are issues that manufacturers
don't inform consumers about, in fact
in regards to
they are claiming the opposite:
Laser and LED's do drop in brightness and colour over
do use more power than normal Lamps
They don't last as long as
read on to learn more...............
|3 LED Projection
LED's or Light Emitting Diodes have been around
since 1962. Originally used for indication purposes rather than illumination.
The latest development of high power LED's for projection created the small
pocket portable market. Using Red, Green and Blue (RGB) solid state LED's they
are limited in brightness (40-300 Lumens) and suitable for small screen
Small compact portable RBG LED projectors are now available with
up-to 1000 lumens but this is still substantially below the 2500 minimum
expected by most business professionals. The problem lay with the Green LED's
not being able to produce as much light as the Red and Blue. To increase the
brightness to this level manufacturers had to develop a Hybrid Laser/LED powered
3 LED Light Engine
Laser & LED Projection
This Hybrid system replaced the Green LED with a Laser. Green Lasers were also
too weak to produce enough light so a blue laser sent through a green phosphor
filter. This system has now been adopted by most manufacturers and has increased
the light output substantially.
Solid state projectors do offer benefits. They are a more robust light
source that can take more knocks than a lamp and if
24/7 operation is required will save on maintenance costs. LED projectors also
offer the convenience of near instant on off, with no need to let the lamp heat
up or cool down, but there are drawbacks too. We would like to correct some of
the misinformation that manufacturers would have you believe.
LASER/LED Light Engine developed by Casio
LASER Phosphor Projection System
Laser Phosphor Light Source Projectors
Laser-illuminated projectors use arrays of
laser sources illuminating a microdisplay engine. In the most common
Laser Phosphor approach, a blue laser is used for creating the blue
color in the final image, but the blue laser is also used to illuminate
a yellow phosphor wheel, which emits yellow light. This yellow light is
then split by a prism or color wheel into green and red light.Maximum
color space is limited to the SMPTE standard.
include the Solid State Light Source combined with phosphor to produce
images that adhere to the SMPTE color space.
- High brightness
- True colors
- 20,000 hour life time
- Large screen sizes
- Installation flexibility
3 LASER RGB Projection System
3 Laser RGB Projectors
RGB laser on the other hand, uses the so-called ‘pure laser’ technology.
Here red, green and blue lasers deliver the light directly. The product
of this technique is an absolutely pure colored light that is split into
the three channels. The light is emitted in a very narrow band in
discrete frequencies. This makes it possible to realize a color space
that reaches BT2020 therefore exceeding even that of Adobe RGB.
RGB (Red, green and blue) laser is the only true “pure laser”
which produces the BT2020 color space using only lasers without the need
for additional components such as LED or Phosphor.
- Highest color space available
- 20,000 hour life time
- Higher resolution (native 4K)
- Installation flexibility
Most of us would think about an LED
projector for one of two reasons.
Low power consumption
This is the main
most solid state projectors are quoting 20,000 Hours (some quote 30,000 for the same
But what's the truth?
The latest independent consumer
watchdog research published in the UK Daily Mail newspaper 2014 (open
pdf) has found that more than a
quarter of LED lamps did not reach their quoted life of 15000 hours. Some even
fail to reach 6000 Hours. 66 out of 230 samples failed before 10000 hours.
These LED lamps are the same technology used in the LED projectors
available. The difference is that in projectors they are run at even higher
power to increase the brightness. This reduces the operational hours further.
expected life span of the DLP panel inside the projector. This compares to
10,000 hours for the highest
conventional Lamp life quoted.
When choosing a projector what needs to be remembered here is that when the LED
projector reaches 20,000 hours it must be
thrown away - no replacement lamps are available. In
comparison an inorganic LCD projector offers the longest panel life (20,000+ is
quoted) and can have a new lamp added
What isn't highlighted is that
the 20,000 hours life is a half life, While this has always been the case for
normal lamps as well, with a Lamp driven projector when the brightness drops you
replace the lamp. Hey there we go full brightness again and you can do this may
times if you buy the right machine (sales can help you with this). With a Hybrid
projector because of the complex light system, changing it is not an option the
cost is too high. So in the bin it goes.
advertised hybrids as constant brightness for the life of the projector.
But the truth is that the brightness drops off. At 10,000 hrs the brightness would be 75% and would be 50% at 20,000 hours.
Low Power Consumption?
The claim that LED projectors are environmentally
friendly is debatable. LED's are Mercury free, which is very good for the
environment. But after comparing projectors
our database, LED projectors are generally less
efficient, using more power to produce the same brightness. While many of us
expect the opposite because of our experience of LED lighting used in houses.
This reflects in the operating
costs, being more expensive to run than
traditional projectors (comparison below).
Laser LED Advantage
*NOTE the above comparisons are for individual machines, not averages. It is to
show that if power consumption is an issue then there are better options than
Unfortunately we would love to say all is well and
good with solid state projectors, but there are issues. A number of LED projectors have
had issues in producing consistent brightness. Not so long ago a range of high
lumen machines had to be removed
the market because each time the projector was booted the lumens would vary.
Varying from 3500 lumens to 2000 lumens. One
of the main problems that had to be over come to make high light output LED's
was the amount of power needed to produce substantial Lumens and the subsequent
heat produced. The heat can substantially affect the consistency of the LED to
produce a constant brightness. It remains to be seen that this issue has been
solved, especially on the budget models. It can also be said that the higher
the brightness of the projector the more detrimental to the LED's performance.
If we consider the colour, we are told hybrids produce a large colour
gamut, larger than other projection systems. This has always been an objective
of manufacturers to increase the colour gamut (more colours). While a large colour gamut is good,
it has to be implemented correctly and show an improvement for the viewer. While
we see a big difference between the high end LED projectors and the budget
machines. Neither offer the more accurate colour of 3LCD projectors. LED
projector colours tend to be over the top and in your face, not what you will
see in the normal world. Fine for Data presentations but not for Home cinema,
Art, multimedia and photographic installations. We expect this to improve as the
While we covered general brightness drop-off
earlier. It should be noted that if you have three separate light sources, each
will degrade at different rates.
If you see the graphs below you will see this is true. The colour brightness
changes with time and the spectrum reduces. As the graphs
show the coloured LED's used in projectors
deteriorate at different rates - Red dropping to between 94%-86% after just 2000
hours? (note: each graph
displays the results for three different LED manufacturers)
So LED'S loose colour output but while the Laser wont deteriorate as much over time the organic phosphor filter will degrade.
How this will affect your image remains to be seen.
A lamp system will also suffer a drop but a linear drop in each colour.
Price Comparison (May 2013)
Comparing the prices for an XGA, 2500 Lumen projector:
LED projector is RRP $1599, 20,000 hours - No lamp
Lamp projector is RRP $999, 5,000 hours - $307 lamp
We can see the LED projector is $600 more. The
traditional projector offers 5,000
replacement Lamp costs $307. So 2 additional lamps can be bought with the cash
saved from the initial purchase, giving 15000
operation. So while the initial purchase of the LED projector is dearer it
offers a 30% improvement in Operating hours for the same price but the
traditional projector has the potential of a longer operating life.
While we recognise
the advantages of LED projectors
for being solid state and more robust for mobile presentations, the advantages
and less power have to be questioned along with the image quality over time. We
also wanted to point out here that the system isn't the holy grail of