Testing the Microvision SHOWWX and AXAA L1 Laser Pico Projectors

Hey everyone, I'm a longtime lurker who appreciates the information resource this forum has been. Nowadays, I do a lot of science and have a lot of equipment available to me at various labs. I hope to make use of the Microvision Showwx Laser Pico Projector in an upcoming experiment and should be receiving one in a few days.

I was hoping to read a technical discussion of the projector on these forums before I purchased it, but it seems as if no one else has shelled out the money for one. I would like to make this that detailed discussion, so if anyone else was considering on buying one, they can get some much needed 3rd party information here.

Please feel free to pose any questions or tests you would like me to preform on the projector. I will not be opening the unit (sorry!). I have access to a good number of scientific instruments, so feel free to be creative. I'm starting this thread shortly before I receive the projector, because I may end up returning it (if it turns out I cannot use it for what I need). I will, however, try to answer everyone's questions before I do so (so I'm giving everyone a day or two to come up with some questions and tests to save time).

Re: Testing the Microvision SHOWWX Laser Pico Projector

I myself was quite tempted to buy one of these for a while, but decided to hold back and see what they were like, good to see you stepped up to the plate

Re: Testing the Microvision SHOWWX Laser Pico Projector

I'd like to know the picture quality in general, and if the white balance is good. Thanks for doing this, but if I ever buy one it will be taken apart...I take everything apart, it's easy and fun, getting it back together however is a whole 'nother story.

Re: Testing the Microvision SHOWWX Laser Pico Projector

Just got the showwx in. The manual says to charge it for 4 hours before use (I ran it for a bit off the AC adapter just to check it out). Really interesting piece of technology. I've noticed a few quirks already, so I hope to make this a fun thread.

The manual has some interesting specifics on the laser diodes that I hadn't found in previous research:



The class 2 laser warning label is on the bottom of the device. The manual has an extra interesting warning against a class 3b beam (coming right out of the device, it seems). Does anyone know why it warns against "invisible light"? I figure this thing should have a IR filter on it. Or is that just the standard labeling/warning?



Pictures to be posted soon, as it gets dark and the battery charges.

Some interesting side numbers: The AC adapter has an output of 5 volts at 1.6 amps and the battery is 3.7 v with 1.8 Ah.

Re: Testing the Microvision SHOWWX Laser Pico Projector

Interesting! Something you don't want to shine in your eyes at close range then! Well, not that you'd want to do that with a projector anyway, but ...

Looking forward to some pics, especially of the output.

Is it bright compared so say, a regular projector?

Re: Testing the Microvision SHOWWX Laser Pico Projector

Great! Didn't think it would arrive so soon.
Wondering how even the image will be. I presume there shouldn't be any banding at normal viewing distances but how about viewed 2 inches from the screen? Any flicker? How is it during fast scenes in movies?
What instruments do you have at your disposal?

I would even be interested in picture of the outer shell. Screws & such.

Re: Testing the Microvision SHOWWX Laser Pico Projector

It's class 2 because the beam is scanned fast enough past a given point that even though the peak power is >100mW, the average power is <1mW unless you aim the device directly into your eye at close range.

I see "visible and invisible laser radiation when open." The same holds true for even an IR-filtered green pointer.

Re: Testing the Microvision SHOWWX Laser Pico Projector

Case Inspection

The case is made of decent grade plastic. I think I might be spoiled by the Apple's aluminum cases, but this doesn't seem to bad. The whole thing is unbelievably light in weight and the battery feels like half the mass and size.





HaloBlu: The case is made of plastic with four rivet-looking screws. It doesn't look like it's made to be taken apart.





Here's a closeup of the laser opening (there is a flat and clear please of glass you can't see on the very outside). I'll try to get a better macro picture of this at some point, if I can.

Re: Testing the Microvision SHOWWX Laser Pico Projector

Here are some more technical observations. Some of them are a bit preliminary, so I'll try to update them in the future as I refine my measurements.

Speckle

The speckle is fairly noticeable if the image is small (< 1 ft). When the speckle occurs, it appears stronger in the green, teal, and yellow hues. The speckle in the blue and red is much harder to see. This is pretty easy to demonstrate with a standard DSLR camera and some basic image processing:



As speckle is sometimes related to surface properties and wavelength, this effect may not occur on all materials. However, I haven't found any exceptions so far during household use (I will update this if I find one).

Real Life Effect: When the image is large, the speckle grain becomes very subtle (due to the small grain size relative to the giant video). In a dark room (with slightly adapted vision) I easily had a comfortable 80 inch image with pretty much unnoticeable speckle.

Polarization

Interestingly, the green laser is polarized 90 degrees from the red and blue. This is easy to demonstrate by rotating a linear polarizer in front of the projector while projecting a colored pattern (the same one as in the speckle experiment).



Real Life Effect: None that I can think of, as human eyes can't detect polarization. This is a purely technical observation. I'm not totally sure why they would engineer it this way though. If anyone has any ideas please bring them up.

Vertical Scanning

Every other frame the 480 rows of the projected image are moved up and down to fill in the gaps between the pixels. Unfortunately, this vertical scanning effect can be canceled out by moving yourself, or the projector. When this happens you can see large pixel gaps that makes the image almost look like 240 rows high. Each of these 240 rows is in fact two pixel rows with a single pixel row worth of 'gap' between each pair.



Here is the extracted row brightness for 6 images. We can see that the rows are more like sine waves with a 180 degree phase shift for every row movement.



Real Life Effect: There aren't any visible gaps between horizontal pixels. However, you can sometimes see gaps between vertical pixels, if you don't give your eyes enough time to average multiple interlaced frames. The image looks really good if you're sitting still, but they really need to speed up the interlace speed if they're not going to give us progressive scanned images.

Refresh Rate

The refresh rate for this projector is rated at 60 Hz. If this were exact, I should get a image without banding if I set my exposure to 1/60 sec. However, I was unable to eliminate the band even among several different cameras. This makes me think that the refresh rate is some weird non-integer number. By measuring the band size I currently estimate it's a bit under 60 Hz, around 56 Hz. I got this number by the following: 60 - 60*(bandHeight/imageHeight).



Real Life Effect: The downside to this is that I feel as if the refresh rate is a little too slow for people with really sensitive eyes. It bothers me a tiny bit more than a 60 Hz CRT monitor. I think they really ought to speed things up to 120 Hz in future models to eliminate this problem. I wouldn't call this a total deal-breaker though, because in a dark room your eyes blur the frames together (just like at a movie theater with 24 fps).

Re: Testing the Microvision SHOWWX Laser Pico Projector

The blanking on that green laser considering it's DPSS is amazing!

I always thought speckle would be a problem with these, but yeah, you can't really see it at any kid of distance ..

For $500, I'd still say this is a pretty nice deal

Thanks for the writeup!

-Dan

Re: Testing the Microvision SHOWWX Laser Pico Projector

Wow, this is a very in depth review!

I've wondered about those for a while now, and sort of forgot as the bigger Casios came out. Thanks for all the attention to detail! This is a excellent review!

Re: Testing the Microvision SHOWWX Laser Pico Projector

Random Quirks

Startup/Shutdown Time: After pushing the power button, the main projector LED blinks for about 16 seconds and then the red and blue lasers instantly kick in. The green laser takes another 3 seconds after this to slowly increase to full power. When you try to turn the projector off, the lasers power down within a second, but the projector LED lights stay on for another 5 seconds.

Heat and Noise: The Showwx has no internal fan so it is completely silent. Without the VGA adapter, it is remarkably cool, it can get a little warm but is never hot. The VGA adapter is made of metal, and seems to suck the heat out of the projector and hold it. The adapter will actually get hot enough to be uncomfortable to hold.

Resolution Compatibility: The native resolution of 848x480 wasn't supported by my older (~4 years) Dell Latitude D420 laptop. I was able to run it at 600x480, but this crops the image by an appreciable amount. Everything worked fine on my two newer computers (both < 2 years old). The composite video cable worked with my Xbox 360, but only allows 480p (600x480) video. I really wish this thing had a HDMI port.

Ipod Nano Compatibility: The projector plugs into the Ipod Nano directly and runs videos hassle free. Unfortunately, it doesn't work with the picture gallery feature (I think it is supposed to on the IPhone).

Re: Testing the Microvision SHOWWX Laser Pico Projector

dsholz said:

Just got the showwx in. The manual says to charge it for 4 hours before use (I ran it for a bit off the AC adapter just to check it out). Really interesting piece of technology. I've noticed a few quirks already, so I hope to make this a fun thread.

The manual has some interesting specifics on the laser diodes that I hadn't found in previous research:

The class 2 laser warning label is on the bottom of the device. The manual has an extra interesting warning against a class 3b beam (coming right out of the device, it seems). Does anyone know why it warns against "invisible light"? I figure this thing should have a IR filter on it. Or is that just the standard labeling/warning?

Pictures to be posted soon, as it gets dark and the battery charges.

Some interesting side numbers: The AC adapter has an output of 5 volts at 1.6 amps and the battery is 3.7 v with 1.8 Ah.

Click to expand...

For people interested in the Diodes this projector is using the most powerful single mode 635nm Diode by Mitsubishi.:evil:

Link to data sheet
http://www.mitsubishichips.com/Global/content/product/opt/laserdevice/ldindis/638nm/ml5xx54.pdf

Link to article
Mitsubishi Releases ML520G54 Laser Diode for Futre Pocket Projectors

The Blue Diode has nice beam profile too.

Re: Testing the Microvision SHOWWX Laser Pico Projector

I'm buying one

Re: Testing the Microvision SHOWWX Laser Pico Projector

Unfortunately, I don't have access to any fog machines, but it looks like this projector could make for some cool light shows. Here are some pictures taken with the vapor off a pan of boiling water.







I'll see about uploading some videos at some point. Maybe I'll find an actual fog machine somewhere that I can use.

Re: Testing the Microvision SHOWWX Laser Pico Projector

Greetings, I am a new member here today. Thanks for the review.

I have followed Microvision for 20 years, from before they were a public company. This projector is not their first product, they had a monochrome red head gear HUD device several years ago that was bulky and did not sell well. They also had a bar code scanner.

This pico projector is their first color product. It is a scanning laser device – which means that the 3 different color lasers are beamed onto a tiny 1mm mirror that scans the beam back and forth and up and down much like a cathode ray TV set.

The scanning module is very small – the size of a thin mint – and will eventually be used in several different products – like a projector embedded in an iPhone, and an eyeglass form factor retinal display.

To answer a couple of questions in this thread:

The image is not interlaced. The resolution is 848 pixels wide and 480 lines. It is scanned back and forth in the horizontal (fast scan) and up and down in the vertical (slow scan) - 60 frames a second.

The green laser is not a direct emitting green laser diode. It is a frequency doubled laser diode – it takes an infrared laser and doubles the frequency to get the green color – like the green laser pointers. The direct emitting green lasers are not commercially available yet – they will be available this time next year though. The warning label for infrared laser light is for this frequency doubled laser.

Another question was about the polarization of the laser light. The polarization of the light is used to combine the 3 laser light sources into one beam. There is an optical device in the module that is called a combiner. It is hard to describe without a picture – see the patent application referenced here (you may have to download a tiff viewer to see the images)

United States Patent Application: 0070091449

The combiner polarizes the laser light and is used to reflect one color off an angled plate while passing the other color through the plate. This allows for 3 sources to be combined into one beam that is then aimed at the scanning mirror. This is why the green polarization is at 90 deg from the blue and red.

They are developing a 3D projector that will use polarized glasses - like the Avatar 3D glasses.

They are also developing a 720p projector module that will be available this time next year - with brighter lasers and reduced speckle.

They will evolve to a 1080p projector after the 720p.

happy lasing!