Wavelength conversion element, method for manufacturing wavelength conversion element, light source apparatus, and projector

A wavelength conversion element comprising:

• a wavelength conversion layer having a first surface including an excitation light irradiated region irradiated with excitation light and a second surface being opposed to the first surface, the wavelength conversion layer wavelength-converting the excitation light into converted light having a wavelength different from a wavelength of the excitation light;
• a reflection member provided on a portion of the second surface that is a portion including a region that coincides in a plan view with the excitation light irradiated region when the first surface is viewed in a direction of a normal thereto, the reflection member including an inorganic oxide layer and reflecting the excitation light and the converted light;
• a first layer disposed in a first region that faces the reflection member and in a second region that does not face the reflection member on the second surface of the wavelength conversion layer;
• a bonding material so provided as to face the first layer;
• and
• a base bonded to the first layer via the bonding material.