Wavelength conversion wheel and projection device

A projection device, comprising:

• an illumination system, providing an illumination beam;
• a light valve, disposed on a transmission path of the illumination beam to convert the illumination beam into an image beam;
• and
• a projection lens, disposed on a transmission path of the image beam,
• wherein the illumination system comprises an excitation light source and a wavelength conversion wheel, the excitation light source provides an excitation beam, and the wavelength conversion wheel comprises:
• a turntable, having an inner ring portion and a ring-shaped irradiation portion, wherein the ring-shaped irradiation portion is connected to an outer edge of the inner ring portion, and the ring-shaped irradiation portion comprises a wavelength conversion region;
• a wavelength conversion layer, disposed on the wavelength conversion region;
• a pressure ring, pressing against the inner ring portion and having a first surface facing away the turntable;
• an anodized layer, disposed on the first surface;
• and
• a balance weight, disposed on the anodized layer, wherein the surface roughness of the anodized layer is 1 μm to 10 μm,
• wherein the wavelength conversion device is disposed on a transmission path of the excitation beam, the wavelength conversion layer of the wavelength conversion device is adapted to convert the excitation beam into a converted beam, and the illumination beam comprises the converted beam and the excitation beam.