Parallel light source

The invention discloses a parallel light source which comprises a light-emitting element and a light-permeable panel. Light rays emitted by the light-emitting element pass through the light-permeable panel and are converted into parallel light. Birefringent crystals are arranged inside the light-permeable panel regularly. The dimension of the birefringent crystals is the wavelength magnitude of the light rays emitted by the light-emitting element. By means of the parallel light source, the problem that in the prior art, a parallel light source is prone to being diffused is solved, an artificial parallel light source with the larger diameter can be provided, the condition of parallel illumination of sunlight in the natural environment can be simulated perfectly, and the parallel light source has great significance on the development of solar photovoltaic products.