Question OLED herz question

[Traditore]

If "OLED response times are up to 1,000 times faster than LCD, putting conservative estimates at under 10 μs (0.01 ms), which could theoretically accommodate refresh frequencies approaching 100 kHz (100,000 Hz)", why all the TVs are 120hz and only now higher refresh rates emerge on the market?

Just had a dispute with a friend who claimed that 500 and more hz TVs are legit (because, well, oled technology is capable) and not a marketing.

If a TV's processor doubles the frame count and inserts bland frames to further eliminate blur, can we say that it actually refreshes at ~500hz?

Anybody with a truly technical insight on how this works and why?

 

[TJ Hooker]

Guess it depends on what you consider "legit". I consider the "true" refresh rate to be how high a refresh rate the TV can natively accept and display.

Regarding the 'effective' refresh rates TVs advertise, they either use:
a) interpolation, which adds input lag and inserts a frame that is calculated to be 'in between' two real frames (which will be less accurate than a true extra frame)
b) backlight strobing/black frame insertion. No extra information is displayed, they just insert black frames which can reduce persistence and in theory reduce blur.

https://www.rtings.com/tv/tests/motion/image-flicker
https://www.rtings.com/tv/tests/motion/motion-interpolation-soap-opera-effect

Neither of these are as good as having a true, native higher refresh rate.

 

[Glenwing]

If "OLED response times are up to 1,000 times faster than LCD, putting conservative estimates at under 10 μs (0.01 ms), which could theoretically accommodate refresh frequencies approaching 100 kHz (100,000 Hz)", why all the TVs are 120hz and only now higher refresh rates emerge on the market?

The display panel isn't the only component that limits the max refresh frequency. You also need the TV's processor to be able to address lines that quickly, and a cable interface that can send pixel data that quickly.

Just had a dispute with a friend who claimed that 500 and more hz TVs are legit (because, well, oled technology is capable) and not a marketing.

They aren't.

If a TV's processor doubles the frame count and inserts bland frames to further eliminate blur, can we say that it actually refreshes at ~500hz?

The "fake TV refresh rates" can come in multiple forms. Usually the "120 Hz" TVs use frame interpolation, which means that actually do refresh at 120 Hz, but they only take up to 60 Hz input from the source. Then they double the frame rate by calculating what it thinks an "inbetween" frame might look like. This adds massive latency and is nothing like what a "true" 120 Hz experience is like. (On a side note, more and more modern TVs actually do take 120 Hz input, which does make them true 120 Hz displays. But this was extremely uncommon on any model older than a few years ago).

Beyond 120 Hz, generally TVs don't use frame interpolation, because they don't have panels that can refresh that fast or processors that can address lines that fast or calculate interpolated frames that quickly. Instead the "240 Hz" and "480 Hz" TVs use backlight strobing, which mean the display panel only refreshes at 60 Hz (or 120 Hz with interpolation) and they flicker the light source at 240 Hz or 480 Hz or more, and call that a "480 Hz refresh rate" even though it's not refreshing the panel that fast at all. This does a good job of eliminating motion blur, and is a genuinely good feature (and is included in a lot of high end gaming monitors now), but marketing it as a higher refresh rate is completely false.

Last note, plasma TVs commonly had a subfield drive frequency of 480 Hz or 600 Hz, and people often interpret that as "600 Hz refresh rate" just because it is measured in Hz. This is not really a case of false advertisement so much as people interpreting the specs incorrectly (although marketers often took advantage of this by refusing to list the refresh rate, leaving the subfield drive as the only "Hz" measurement on the spec sheet, and things like that, plus some retailers would list it as "refresh rate" because they didn't know any better, so... yeah. But plasma "480 Hz" and "600 Hz" are a different story from LCD fake refresh rates.)