ZHCSIG4A July 2018 – June 2019 DLPC3434
Two different types of glasses are often used to achieve synchronization. One relies on an IR transmitter on the system PCB to send an IR sync signal to an IR receiver in the glasses. In this case DLPC3434 output signal GPIO_05 can be used to cause the IR transmitter to send an IR sync signal to the glasses. The timing for signal GPIO_05 is shown in .
The second type of glasses relies on sync 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 sync information to the glasses. This can save cost, size and power in the projector.
For generating the DLP Link sync information, one light pulse per DMD frame is outputted from the projection lens while the glasses have both shutters closed. To achieve this, the DLPC3434 will tell the DLPA2000 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 15 and Figure 16.