Wavelength conversion module, method of forming the same and projection apparatus

A method of forming a wavelength conversion module, comprising:

• forming a rough surface on a substrate, wherein the rough surface comprises two first regions and a second region, and the second region is located between the two first regions in a radial direction on the substrate;
• coating a plurality of diffuse reflection particles on the rough surface of the substrate, wherein a second concentration percentage by volume of the plurality of diffuse reflection particles in the second region is greater than or equal to a first concentration percentage by volume of the plurality of diffuse reflection particles in one of the two first regions;
• and
• coating a wavelength conversion material and a bonding material on the substrate to form a wavelength conversion layer, wherein the plurality of diffuse reflection particles are located between the wavelength conversion material and the substrate.

A projection apparatus, comprising:

• a wavelength conversion module, comprising:
• a substrate, having a rough surface comprising two first regions and a second region, wherein the second region is located between the two first regions in a radial direction on the substrate;
• and
• a wavelength conversion layer, located on the substrate and comprising a wavelength conversion material, a bonding material and a plurality of diffuse reflection particles, wherein
• the wavelength conversion material is distributed in the bonding material, and the plurality of diffuse reflection particles are located on the rough surface of the substrate, and the plurality of diffuse reflection particles are located between the wavelength conversion material and the substrate, and wherein a second concentration percentage by volume of the plurality of diffuse reflection particles in the second region is greater than or equal to a first concentration percentage by volume of the plurality of diffuse reflection particles in one of the two first regions;
• and
• an excitation light source, configured to emit an excitation light beam, wherein the excitation light beam is transmitted to the wavelength conversion module and converted into an illumination beam by the wavelength conversion module;
• a light valve, located on a transmission path of the illumination beam and configured to convert the illumination beam into an image beam;
• and
• a projection lens, located on a transmission path of the image beam and configured to project the illumination beam.