Laser-phosphor technology: science fiction now science fact

Laser-phosphor technology is advancing rapidly. But what is it, what are the advantages of this technology and for what applications is it best suited?

There are many advantages of lamp-less laser-phosphor light source technology.  For example:
•    There is no lamp and therefore maintenance requirements are minimal
•    Brightness is more consistent than lamp-based projectors, which are subject to brightness fluctuations as the lamp is used (brightness decay) and replaced
•    It is quieter due to higher efficiency and so less requirement for cooling
•    Colour reproduction is brilliant
•    Due to the solid state light engine, the projector is able to operate in unusual positions, including portrait and downward projection

As a result of these benefits, laser-phosphor projectors are ideal for venues where ceilings are high and the projector is fairly inaccessible for maintenance, such as university lecture theatres, digital signage applications and museums/professional installations where usage hours tend to be higher and there are accessibility/maintenance restrictions.

It is also ideal for quieter environments such as smaller meeting rooms or those with low ceilings.

With such a wide choice of projectors – lamp-based, LED and laser - it is important to look at the application and venue to ascertain whether a laser-phosphor projector is the best solution.

If the projector is needed for lengthy usage with minimal downtime or the projector would be fairly inaccessible after installation, then this may be the best option.  

Also if colour accuracy is important, it may also be the best choice – although the colour performance of lamp-based DLP projectors varies with the type of colour wheel used. Some, like Optoma’s EH7700, provide colour wheels options so the colour performance and brightness can be tailored to the application – so it is important to look at all factors.

Optoma has recently expanded its range of laser-phosphor ProScene projectors with the 6,000-lumen ZU650 and the ultra-wide short throw, ZH300W.

The technical bit
Unlike the laser beams you may have seen in Bond films, no raw laser light is emitted from the lens of the projector.  So how does it work and what is the difference between laser and laser-phosphor projectors?

With a pure laser - the red, green and blue light from three laser diode arrays (one each for red, green and blue) is combined then passed through an optical diffuser. It is this diffused light that is used to illuminate the projector’s DLP chip and produce the image.
 
A laser-phosphor projector is slightly different in that it uses one blue laser.  This blue light is diffused and used as the blue light component to illuminate the DLP chip. The blue laser is also used to energise a phosphor wheel that emits yellow light. This is then split into its red and green components and used to illuminate the DLP chip.

Are you ready for the revival of video?

Like the resurgence in interest for vinyl records, video tapes could see a revival according to reports.

 

After the first video cassette recorder (VCR) went on sale at Dixons in 1978, demand for VCRs fell due to the rise of DVD players in the 1990s.

 

But the past few years have seen a huge influx in VHS collectors according to Daily Grindhouse.  Video collectors say films made for VHS look strange when cleaned up for higher-definition DVDs. They prefer the grainer quality of the VHS format, in the same way a vinyl collector might speak about the warmth of a record’s sound.

 

“These are movies that feel too cleaned-up on DVD and Blu-ray, as if they were never meant to look that good. Watching them on VHS is closer to the way the director intended it to look,” Dan Kinem, a VHS collector, told Collectors Weekly.

 

People wanting to reminisce with their old films on their trusty video cassette recorder (VCR) will need a projector to create the full cinema experience.  But modern-day projectors don’t always come with the inputs needed to connect with the older VCR technology.

 

VCRs would not have a HDMI output that can connect to the HDMI inputs in most modern projectors. It is more than likely you will need to use either the composite or S-video ports. 

 

So, if you want to dust off your video classics, you will need to choose a projector carefully to ensure that it has all the inputs that you need.  The Optoma HD36 is a good option as it is bright, has fantastic picture quality but, more importantly, has the plethora of inputs to ensure it is compatible with all devices – both modern and historic.  These include composite and S-video.

 

Composite video cables have a small, metal-tipped plug (also known as a RCA plug) which is usually yellow.  S-Video cables have a slightly larger plug with a series of small, delicate-looking pins jutting out of each end.  If the VCR is really old, it may have a SCART output for which you can get SCART to composite adaptor or cable.

 

You will also need to connect sound from the VCR to the projector via a set of stereo RCA plugs.  These are usually red for the left channel and white for the right.

 

Those that remember, and still have, laser disc players which played vinyl analogue video - the forerunner to DVD - will most likely need to use the SCART to composite adaptor to connect to the projector.