Pixel expansion device and projection equipment

The embodiment of the invention provides a pixel expansion device which comprises a diffraction assembly, a first polarization conversion device and a birefringent crystal device, the diffraction assembly comprises a driving device, plane glass, a first diffraction device and a second diffraction device, and the driving device is used for applying voltage to the first diffraction device and the second diffraction device. The diffractive component is arranged on the substrate, so that the diffractive component has a first state and a second state, in the first state, the diffractive component receives the modulated light and emits the modulated light along a first path, and in the second state, the diffractive component receives the modulated light and emits the modulated light along a second path. The first polarization conversion device is used for receiving the modulated light from the diffraction assembly and selectively switching the polarization state of the modulated light. The birefringent crystal devi