DLPC3470 datasheet(45/70 Pages) TI1

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DLPC3470

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DLPS110 – APRIL 2018

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8.3.2.8 3-D Glasses Operation

For supporting 3D glasses, the DLPC3470 controller -based device set outputs synchronization information to

synchronize the Left-eye-to-Right-eye shuttering in the glasses with the displayed DMD image frames.

Two different types of glasses are often used to achieve synchronization. One type relies on an infrared (IR)

transmitter on the system PCB to send an IR synchronization signal to an IR receiver in the glasses. In this case

DLPC3470 controller output signal GPIO_04 can be used to cause the IR transmitter to send an IR

synchronization signal to the glasses. Figure 8 shows the timing for signal GPIO_04..

The second type of glasses relies on synchronization information that is encoded into the light being outputted

from the projection lens. This is referred to as the DLP Link approach for 3D, and many 3D glasses from different

suppliers have been built using this method. This demonstrates that the DLP Link method can work reliable. The

advantage of the DLP Link approach is that it takes advantage of existing projector hardware to transmit the

synchronization information to the glasses. This can save cost, size and power in the projector.

For generating the DLP Link synchronization information, one light pulse per DMD frame is outputted from the

projection lens while the glasses have both shutters closed. To achieve this, the DLPC3470 controller will tell the

DLPA2000 device or DLPA2005 when to turn on the illumination source (typically LEDs or lasers) so that an

encoded light pulse is output once per DMD frame. Since the shutters in the glasses are both off when the DLP

Link pulse is sent, the projector illumination source will also be off except for the when light is sent to create the

DLP Link pulse. The timing for the light pulses for DLP Link 3D operation is shown in Figure 27 and Figure 28.

Figure 27. DLPC3470 controller L/R Frame and Signal Timing for DLP Link

DLPC3470 Datasheet(PDF) 45 Page - Texas Instruments