Originally Posted by ovawe
2. so if they tried to do strobing on a 120hz IPS (even if 120hz was interpolated) what would the disadvantage vs on TN? response time slow on IPS, so more trailing artifacts?
Yes. It's also the reason why active 3D is not done on computer monitor IPS panels -- too much leakage between refreshes -- crosstalk -- which also interferes with good motion-blur-eliminating stroboscopic backlight operation.
That said, some HDTV (that uses IPS panels) have achieved active 3D shutter glasses operation, and so can benefit from pure stroboscopic backlight operation -- because the ability to do active 3D is a good determinator of improved stroboscopic backlight efficiency, due to the requirement for individual, completely refreshed frames (normally for 3D active shutter glasses). This situation happens to make it practical to shatter the pixel persistence barrier
. This is done by keeping the backlight turned off while waiting for pixel transitions. The stroboscopic flash (during completed refreshes) can be shorter than the time the pixels spent transiting. In this case, motion clarity is no longer bounded by the speed of the LCD panel, but by the speed of the flash instead.
The ASUS VG278H (2ms TN) has an effective MPRT of 1.4ms during LightBoost=10% operation. Problem is that IPS pixel transitions often take a full refresh to finish transiting, leaving little time for stroboscopic backlight operation. At 120Hz, you only have 8.33ms. And that's for all GtG transitions (transitions between all pixel color values), and we all know that a manufacturer rating of "5ms" often means 10ms real-world transition for some shades of colors. In this case, a stroboscopic backlight is not able to bypass pixel persistence. Even LightBoost display still sometimes have problems completely eliminating all faint trailing artifacts, but LightBoost manages to make trailing artifacts disappear by more than 99% (similar in level of intensity to to 3D crosstalk) on the best displays at the best settings.
3. anyone kno what the LG "motion eye care" feature does? seems like it strobes the backlight when i did my finger waggle test, but couldn't see any difference in the video playing on the tv at the store
For good stroboscopic/scanning backlight comparisions, you generally need:
1. Motion at fps=Hz. Frame rate matching refresh rate.
2. No source based blur (e.g. no overcompression, no soft focus, fast camera shutter) in the video material
As a result, it is much easier to analyze using video game material than with video material.
Also, many scanning backlights fall short of their abilities (see Scanning Backlight FAQ
and TFT Central: Motion Blur Reduction Backlights
) so for reasons already explained in these links, scanning backlights do not reduce motion blur as significantly as full-screen-at-once stroboscopic backlights found in active-3D-compatible panels (those types of backlights are the most efficient at eliminating motion blur, by a significant margin).Edited by mdrejhon - 5/9/13 at 1:19pm