Light wavelength conversion element and projection apparatus

A projection apparatus, comprising an illumination system, a light valve and a projection lens, wherein

• the illumination system comprises an excitation light source, a light wavelength conversion element and a light condensing lens, wherein
• the excitation light source is configured to emit an excitation beam;
• the light wavelength conversion element has a light incident side, the light wavelength conversion element is configured to receive the excitation beam from the light incident side,
• the light wavelength conversion element comprises a substrate and a light wavelength conversion substance;
• wherein
• the substrate has a surface facing the light incident side and is configured to rotate about a center axis, the surface has at least one microstructure protruded toward the light incident side;
• the light wavelength conversion substance is disposed on the surface and covers the at least one microstructure, and a width of the microstructure along a radial direction of the substrate is smaller than a width of the light wavelength conversion substance along the radial direction,
• wherein when the excitation beam is transmitted to the light wavelength conversion substance, the light wavelength conversion substance is excited by the excitation beam and emits a conversion beam, the conversion beam forms a light spot on the light wavelength conversion substance,
• wherein an energy density distribution of the light spot has at least one peak value, a position corresponding to the at least one peak value on the light wavelength conversion substance corresponds to a position of the at least one microstructure, and the illumination system outputs the conversion beam or the excitation beam as an illumination beam;
• the light condensing lens is disposed on a transmitting path of the excitation beam, wherein a focus of the light condensing lens is deviated from the light wavelength conversion substance on the substrate;
• the light valve is disposed on a transmitting path of the illumination beam to convert the illumination beam into an image beam;
• the projection lens is disposed on a transmitting path of the image beam.