Jeroen, Thank you for the richly detailed course on the state of 3D cinema! I now have a lot of Googling to do. However, my original question was a bit simpler. I wondered what would happen if you tried to use LCD shutter glasses with existing displays, as you originally proposed. I have two LCD displays in my home. When I wear polarized sunglasses and view my LCD television, the image is blocked out if I tilt my head 45 degrees to the right (from my perspective), and fully bright if I tilt my head 45 degrees to the left. My other LCD display behaves in the opposite manner. when I tilt my head 45 degrees to the left, the image is blocked out. Obviously both LCD manufacturers made their displays with the final polarizer on a 45 degree bias to horizontal in order to minimize the blocking effect of someone viewing while wearing polarized sunglasses (which are vertically polarized.) I've also noticed this same effect on gas pumps with LCD displays, and with in-car navigation screen displays. So my question was what effect wearing LCD shutter glasses would have on the viewing experience. If the glasses had their final polarization lenses on the same bias as the LCD television, then when the glasses were in the "clear" mode all of the light would get through. However, this same bias on another television might block all light! So the only way to make glasses compatible with all LCD televisions is to have the final polarization either vertical or horizontal, guaranteeing that everybody will see the image, but also that everybody will experience reduced brightness and contrast, unless they cock their head like a Collie hearing her master speak. John ----- Original Message ----- From: Stessen, Jeroen To: opendtv@xxxxxxxxxxxxx Sent: Monday, December 07, 2009 3:14 AM Subject: [opendtv] Re: 1080p questions John Shutt asked: Ø What is the effect of wearing polarized glasses (LCD shutters on 3D glasses Ø are by definition polarized lenses) when viewing an LCD display? The effect, whatever it is, is intentional ! I was referring to 3D displays of the "Arisawa" or "X-pol" type. In front of the last polarizer ("analyzer") a striped retarder is applied. This changes the linear polarization of the light into alternately left and right circular polarized light. The glasses, which are exactly like the RealD glasses in the cinema, have left and right circular polarized filters. The result is that one eye sees only the odd lines, and the other eye sees only the even lines. Each eye sees only 540 lines. Other than this loss of resolution, and the loss of 50% brightness, and often some vertical aliasing due to insufficient anti-aliasing filtering, it is a very pleasant experience ! Without the glasses the same display can be used as a 2D display with the full 1080p resolution. There may be some light loss because of a black matrix that is applied to increase the vertical viewing angle. This is because the striped retarder is currently applied on the wrong side of the glass, so there is a vertical parallax issue. An in-cell retarder would solve that, it is in the pipeline. ...snip... Finally, a 3D LCD panel (or projector), may also be run with frame-sequential XpanD shutter glasses. The response time of the panel now becomes a major issue, causing some crosstalk between the left and right images. It may be improved by running the panel at 240 Hz, inserting black fields (60 times: left, black, right, black, ...), scanning the backlight, and keeping the duty cycle of the 2 glasses well below 50% each. The light output will drop a lot, even though the light was already linearly polarized so the LCD shutter glasses do not take away another 50%. There is the promise of significantly faster LCD panels, based on OBC or Bluephase effect.