Patent ID: 11953816
Assignee: RICOH COMPANY, LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 15:
16. A wavelength conversion plate comprising:
a conversion region on a base surface, the conversion region including a wavelength converter to receive excitation light and generate a color different from a color of the excitation light; and
a reflection region on the base surface, the reflection region to reflect the excitation light, wherein:
the reflection region includes:
a transmissive diffusion surface to diffuse the excitation light;
a transmissive layer to transmit the excitation light; and
a reflection surface to reflect the excitation light,

the transmissive diffusion surface is in a position separate from a surface closer to the base surface, of the wavelength converter, toward a direction from which the excitation light is incident,
a position of the transmissive diffusion surface is determined such that a relation

0<h<2k

is satisfied, where k represents a thickness of the wavelength converter and h represents a distance between the base surface and the transmissive diffusion surface.