NEW: This set utilizes LEDs as backlights driven by the Inverters. These LEDs are manipulated in accordance to the necessary Light Source intensity according to the video content (Contrast Ratio) demands. Control signals to the Inverters are sent out from the T-CON PWB. B+ (24V) is sent from the Power Supply (SMPS). There are 8 Vertical columns and 16 horizontal rows for a total of 128 individual LED Blocks. Each Block contains 12 LEDs (3 X 4).
THE BENEFITS OF LED BACK-LIGHTING
- Much brighter & longer life time - LED100K hoursvs. CCFL 60K hours.
- Expanded color gamut - 110% of ATSC gamut (vs. 90% for CCFL)
- Eco friendly (No Hg “Mercury) & less power consumption.
- Mega Contrast - (2,000,000:1dynamic Contrast Ratio.
LED BACK-LIGHTING
CCFL BACK-LIGHTING
LED BACK-LIGHT SECTION [FOUR BLOCKS]
BACK-LIGHT SECTION - SINGLE BLOCK
BACK-LIGHT INVERTER SECTIONS"M" & "S"
LED LAYOUT
The picture below shows a close up of one of the 1536
individual LEDs contained within the backlights. There are two sides each with
768 LEDs (64 blocks) in each side. And
individual block is manipulated by the T-CON board. These blocks are manipulated
Global (All at once) and in accordance with the video intensity at the specific
location of the block of LEDs for that video content (Local). In other words,
if the video is dark in the area of the screen that is being illuminated by a
block of LEDs, they will be dimmed. Not
counting “Black” there are 3 levels of intensity of the LEDs. The Overall intensity of the backlights is
manipulated by the “Global” Dimming signal from the BCM chip called
Digital-Dimming.
- A minimum of 30V required to light all 12 LEDs in a block Bottom 2 pins on the M Top 2 pins on the ‘S’.
- Panel Disassembly required. (Note during warranty period.) A simple Forward Bias diode check will cause the diode to illuminate if it is good. Check any pin on the right to any pin on the left.
TESTING ONE LED
TESTING TWO LEDs
LOCAL DIMMING
- The picture below shows a relationship between the LEDs reaction to real time video on the screen.
- A good example shown by A, B, C and D show the dark areas of the screen. As can be seen by the backlight LEDs, they are dimmed out in the same area.
- To see a representation of the “Local Dimming” look on the Customer’s Menu, turn on Local Dimming Demo.
GLOBAL LED BACK-LIGHT BRIGHTNESS CONTROL CIRCUIT {Click on picture to Enlarge}
TESTING THE BACK-LIGHT BLOCKS
