I was looking at a video that showed a Google Prototype the other day and it became obvious to me that they were using a color filter LCOS panel.  I have seen speculation that Google was using DLP or OLED devices but this is clearly wrong.  And any speculation of it being a laser beam scanning device is simply silly (LBS is way too big and expensive)

In some recent videos and articles about Google’s Glass development show the guts of the prototype.   It looked pretty clear it was an LCOS panel mounted on a PCB going through a beam splitter to the light guide for the see-through display.   Below is a crop of the picture from the Verge Article “I Used Google Glass . . . “

What caught my eye was that there were only two wires going to the LED illumination (in a white package — see picture above) which was indicative of a white LED.   A field sequential device would have to have separate wires for each LED (or laser).     To get a color display starting with a white light source, the device had to have color filters on it and so by a process of elimination, it had to be a color filter LCOS device.

Knowing that Himax made color filter LCOS,  I searched through some pictures I took of HiMax’s panels (since they made color filter LCOS) and found some pictures I took at an electronics show Hong Kong in October 2010 (see picture on the right above.   The optical engine was for a about a 10 lumen front projector so the optical engine is a bit different (particularly the lens) but the panel in the Google prototype is a perfect match to the Himax color filter one used used by Shiny Optics (then owned by Himax) in 2010.  In the close up crop (and rotation) next to the Google prototype (see top images), the flex connector on the PC board, the PC board with its mounting holes (red arrows), and PC-board silk screen markings (green and blue arrows) are a match.

Note, the resolution of the Himax display was only 320 by 240 pixels (by 3 colors/pixel) for this panel.     This resolution may seem very low, but remember that Google glass is only putting an image in the upper corner of a person’s field of view so it only covers a small part of the viewing area.   This is also consistent with the latest Google Glass video (frame captured below) which has a low resolution display (note the simple fonts and few text characters across the screen).

It got me that the panel was oriented the wrong way in the Verge video/article (the image would come out long in the vertical direction).  But then another article by Fast Company Co Design article “Google’s Project Glass: Inside The Problem Solving And Prototyping” (see second picture below) had the panel rotated.    Since the Fast Co Design picture shows a smaller system, I assume it is a later prototype, but it uses the same panel (same telltale markings and a “white” LED).

But note, I would tend to doubt that Google is still using color filter LCOS.   Himax has taken most of the information about LCOS down from their site and may be out of this business.  But more importantly, for a low resolution and low brightness (near eye, rather than a projector) application such as this one of only about 320 by 240 pixels (more on the resolution of the Google Glass demo in my next article), a smaller more compact design could be done with a transmissive color filter panel which is what I suspect Google is now using.

Lastly, I’m sorry to be away so long.  I got very busy with work and got out of the habit of posting.  I have some things to write about including more on Google Glass, green lasers, Heads Up Display, and more on technology in general,  so hopefully I will be a bit more frequent.

Karl