An optical system of the disclosure includes: a fluorescent unit that includes a phosphor region excited by a first color light beam to output fluorescent light including at least one color light beam, and outputs the first color light beam in a first period and outputs the fluorescent light in a second period; one or two light valves illuminated by at least one of the first color light beam or the fluorescent light; and a region division element including first and second regions and disposed on an optical path between the fluorescent unit and the one or two light valves, the first region outputting the first color light beam and the fluorescent light from the fluorescent unit to be able to reach the one or two light valves, the second region outputting the fluorescent light from the fluorescent unit to be able to reach the one or two light valves.

To provide a phosphor wheel capable of restraining vibration caused by a driving unit for rotatably driving a wheel and reducing noise in a high frequency band. The phosphor wheel includes: a wheel substrate that has a surface on which a fluorescent material is provided; a driving unit that rotates the wheel substrate; a support portion that supports the driving unit and is fixed to a housing; and a buffer member that is provided to fill a space between the support portion and a part of the housing.

Provided is a partial drive-type light source device including an excitation light source that is formed from a plurality of light-emitting elements and is partially drivable, a phosphor sheet disposed at a position separated from the excitation light source and containing a phosphor that converts at least part of a wavelength region of incident light from the excitation light source and releases emitted light in a wavelength region differing from the incident light, and a wavelength-selective reflection film that is disposed between the excitation light source and the phosphor sheet and that transmits at least part of light in the wavelength region of the incident light from the excitation light source and reflects at least part of light in the wavelength region of the emitted light from the phosphor sheet.

An illumination device includes: a laser light source; a cylindrical body disposed such that light emitted from the laser light source enters the cylindrical body at a first end portion side of the cylindrical body and passes through the cylindrical body; a reflector disposed so as to reflect light passing through the cylindrical body; and a ring assembly comprising a ring-shaped inner circumferential surface configured to reflect and propagate light from the reflector. The reflector includes: a first reflecting surface configured to reflect a first portion of light emitted from the laser light source, and a second reflecting surface configured to reflect a second portion of light emitted from the laser light source. The ring assembly further includes a fluorescent surface adapted to emit fluorescence by light reflected and propagated at the inner circumferential surface.

An illumination device includes: a laser light source; a cylindrical body disposed such that light emitted from the laser light source enters the cylindrical body at a first end portion side of the cylindrical body and passes through the cylindrical body; a reflector disposed so as to reflect light passing through the cylindrical body; and a ring assembly comprising a ring-shaped inner circumferential surface configured to reflect and propagate light from the reflector. The reflector includes: a first reflecting surface configured to reflect a first portion of light emitted from the laser light source, and a second reflecting surface configured to reflect a second portion of light emitted from the laser light source. The ring assembly further includes a fluorescent surface adapted to emit fluorescence by light reflected and propagated at the inner circumferential surface.

The present invention has as its object the provision of a fluorescent light source device capable of stably obtaining high luminous efficiency and a production process of the same.

The fluorescent light source device of the present invention includes a fluorescent plate which has a fluorescent light-emitting layer formed of a polycrystalline material and in which a periodic structure body is formed on an excitation light incident side of the fluorescent light-emitting layer. The fluorescent plate has a thermal diffusion layer which is directly bonded to a front surface of the fluorescent light-emitting layer on the excitation light incident side and has a thermal conductivity larger than that of the fluorescent light-emitting layer, and a high thermal conductive layer provided on a back surface of the fluorescent light-emitting layer opposite to the excitation light incident side. The high thermal conductive layer is formed of a light reflection layer and a bonding layer made of a metal, and the fluorescent plate is provided so as to cover a part of a surface of a heat dissipation substrate disposed on a side of the high thermal conductive layer side.

An optical unit according to one aspect of the present invention includes a substrate, and a fluorescent layer provided on the substrate. The fluorescent layer includes an adhered portion adhered to the substrate and a non-adhered portion that is not adhered to the substrate. The substrate has a concave portion containing an air gap and an adhesive. The adhered portion is part in the fluorescent layer corresponding to a region where the adhesive is provided. An end of the fluorescent layer is located outside the concave portion.

A photoconversion device includes a first wavelength converter and a long-pass filter. The first wavelength converter receives excitation light from an output portion and emits fluorescence having a longer wavelength than the excitation light. The long-pass filter transmits the fluorescence emitted by the first wavelength converter and reflects the excitation light transmitted through or reflected from the first wavelength converter to enter the first wavelength converter.

A light source unit of a vehicle lighting system includes: a light source to emit excitation light; a light generating unit including a luminescent layer to emit generation light by being irradiated with the excitation light and a holding member holding the luminescent layer; and a lens member to output generation light from the luminescent layer toward the front, with the light source unit mounted on the vehicle.

A light source unit of a vehicle lighting system includes: a light source to emit excitation light; a light generating unit including a luminescent layer to emit generation light by being irradiated with the excitation light and a holding member holding the luminescent layer; and a lens member to output generation light from the luminescent layer toward the front, with the light source unit mounted on the vehicle.