A projection display apparatus includes a polarization beam splitter, a first phase compensation plate including two layers, and a light modulator. The probe card assembly includes a plurality of probes supported by a support substrate, each of the plurality of probes including an end portion extending away from the support substrate. The third lens group G3 has a front lens subset G3F of positive refractivity and a back lens subset G3B, and the back lens subset G3B alone is moved orthogonal to the optical axis to correct a blur of an image on the image plane caused by a shake of photographer’s hands. The power installation can make a relatively large amount of power available even when the flow speed of the marine current is relatively low, for example, in the region of 1. A lens assembly including the optical lens is also provided. Nodes in the network transmit link alive symbols to indicate that a link is alive.