A New Approach to the Response Time Measurement Method of OLED TVs

Effect of the line scanning driving of active‐matrix display on the measurement of display temporal characteristics

“…For the same probe diameter, more pixels will be inside the measuring area, and the temporal response will be measured to be larger for the display with a smaller pixel size. 15,16 The relative amplitude inside the circles on the recorded image was calculated using Equation ( 2) to estimate the intensity using an LMD probe of the finite size as follows: Figure 7 shows the relative amplitudes inside the circles with diameters of 6, 45, 90, and 180 image pixels on the recorded image. These ranges correspond approximately to circles with diameters of 4, 29, 59, and 118 pixels on the display, respectively.…”

“…The temporal response time of OLED has been reported to be less than 10-50 μs. 15,16 Hence, an OLED monitor was selected as the sample display to investigate the temporal behavior under the condition of T D < < T C in Figure 3. The selected OLED monitor had a resolution of 3440 Â 1440 pixels, a pixel size of 0.232 mm, and a frame rate of 175 Hz.…”

“…It is known that the scanning driving of the display can affect the measurement of response time. [12][13][14][15][16] However, this effect becomes more noticeable for displays whose response times are comparable to or shorter than the shutter time of a light measuring device (LMD).…”

“…When a display frame changes, signals for the AM display are not simultaneously applied to all the pixels of the display but are applied sequentially line‐by‐line, and the luminance of each pixel changes accordingly with the different timings. It is known that the scanning driving of the display can affect the measurement of response time 12–16 . However, this effect becomes more noticeable for displays whose response times are comparable to or shorter than the shutter time of a light measuring device (LMD).…”

“…The temporal response times of the commercial displays varied. The response time of LCD was reported to be a few milliseconds, whereas the response time of OLED was reported to be less than tens of microseconds (μs) 15,16 . For example, when a probe diameter of 10 mm is used to measure the display of 60 Hz and vertical resolution of 3840, N L × t U = 43 × 4.34 μs = 0.17 ms. As this value is much smaller than a few milliseconds that is the typical response time of then LCD, the effect of the line‐driving on the measured result of LCD can be considered negligible.…”