What They Say
DD contributor Pete Palomaki posted a video showing a teardown of a broken TCL 5 Series TV and found that the FALD LED backlight had YAG phosphor LEDs. The set is advertised as being a QD set so the result was slightly surprising. The RGB peaks of the front of screen spectrum were fairly pure. The diffuser had some white scattering dots on the surface (5:24) with different sized dots towards the edge. There was a QD film in the stack to produce red and green and they both had a <30nm FWHM which is very good (6:19).
The BLU has blue LEDs, but there are four very think yellow dots around each LED (7:09) and these dots are YAG phosphor (which converts some of the blue light to wideband green and red).
The team blocked the phosphor layer to see if the emission at the front of the screen changed, but it didn’t change very much. The lens on the LED is an interesting shape (9:30) and he refers to a paper that describes the lens operation. Taking off a lens shows how a hot spot is very strong if it is absent.
The reasons for the YAG phosphor is not so clear to Palomaki, and he speculates on those reasons.
He previously looked at a Vizio set (Colour Shifts, BEFs and Quantum Dots) and (Pete Palomaki Tears Down a QD TV).
What We Think
Pete is planning another teardown soon. (BR)
