Light source device and image display apparatus

A light source device comprising:

• an excitation light source including:
• one or more light emitters to emit excitation light;
• and
• an optical element to convert the excitation light, emitted from the one or more light emitters, into an excitation beam;
• a wavelength converter including:
• a reflector to reflect the excitation beam;
• and
• a phosphor layer to emit fluorescence having a wavelength different from a wavelength of the excitation beam;
• a dichroic mirror to:
• transmit the fluorescence;
• and
• reflect the excitation beam;
• a light homogenizer having an incident surface to homogenize the excitation beam and the fluorescence incident on the incident surface;
• a first condensing optical system having an optical axis to:
• transmit the excitation beam reflected from the dichroic mirror through one half of an optical effective surface of the first condensing optical system relative to the optical axis;
• and
• condense the excitation beam onto the wavelength converter;
• a second condensing optical system having the optical axis to:
• condense the excitation beam, reflected from the reflector of the wavelength converter and transmitted through an opposite half of the optical effective surface of the first condensing optical system relative to the optical axis, onto a first focal position on the incident surface of the light homogenizer;
• and
• condense the fluorescence emitted from the phosphor layer of the wavelength converter onto a second focal position on the incident surface of the light homogenizer,
• wherein at least one of a position or an orientation of one of:
• the optical element of the excitation light source;
• the dichroic mirror;
• or
• the wavelength converter,
• is adjustable to adjust the first focal position of the excitation beam and the second focal position of the fluorescence on the incident surface of the light homogenizer.