The present invention provides a safe ultraviolet light irradiation device that uses ultraviolet light safe to the human body and has a wide range of microorganism elimination and sterilization effects, and also provides an ultraviolet light emitting element provided with: an electrode substrate having a pair of electrodes; at least one cylindrical or flattened cylindrical glass tube disposed on the electrode substrate so as to face both of the electrodes, the glass tube having both end parts sealed; a xenon gas-containing discharge gas enclosed inside the glass tube and generating an electric discharge due to a voltage applied to the electrodes; and a phosphor layer formed on an inner surface of the glass tube and emitting light when excited by the electric discharge, wherein the glass tube is made of borosilicate glass or quartz glass; and the phosphor layer is made of a phosphate-based fluorescent material and has an emission spectrum having a peak half value width within a wavelength range of 50 nm or less with a peak at a wavelength of 20310 inm on an illuminance basis.

The purpose of the present invention is to provide an irradiation unit and a lamp unit in which the risk of damaging a lamp is reduced due to simplified replacement of the lamp. The present invention includes: a lamp unit on which an excimer lamp is mounted, the excimer lamp having a light-emitting tube that extends in a first direction and a first electrode and a second electrode that are arranged to face each other in a radial direction of the light-emitting tube; and a housing which accommodates the excimer lamp due to the lamp unit being inserted therein, the lamp unit includes a plate material, a restriction member which protrudes from a first main surface and restricts movement of the excimer lamp inside the housing, and a power supply portion that is disposed on a second main surface side of the plate material positioned outside of the housing and that supplies electric power to the excimer lamp when the plate material closes an insertion opening.

An LSP broadband light source is disclosed. The LSP broadband light source may include a pump source configured to generate a pump beam and one or more collimating optical elements configured to collimate the pump beam into a collimated pump beam. The light source may include one or more focusing optical elements and a beamsplitter located at a conjugate plane between the one or more collimating optical elements and the one or more focusing optical elements. The light source may include a gas containment structure. The beamsplitter may be configured to split the collimated pump beam into a set of pump beamlets, wherein the one or more focusing optical elements are configured to focus the set of pump beamlets to a set of focus positions within the gas to generate multiple plasma regions at the different focus positions.

An LSP broadband light source is disclosed. The LSP broadband light source may include a pump source configured to generate a pump beam and one or more collimating optical elements configured to collimate the pump beam into a collimated pump beam. The light source may include one or more focusing optical elements and a beamsplitter located at a conjugate plane between the one or more collimating optical elements and the one or more focusing optical elements. The light source may include a gas containment structure. The beamsplitter may be configured to split the collimated pump beam into a set of pump beamlets, wherein the one or more focusing optical elements are configured to focus the set of pump beamlets to a set of focus positions within the gas to generate multiple plasma regions at the different focus positions.

The inactivation apparatus includes: an excimer lamp that includes a luminous tube, and a pair of electrodes, and generates ultraviolet light having a main emission wavelength band within a range of 190 nm or more and less than 240 nm in the luminous tube when a voltage is applied between the pair of electrodes; and an optical filter into which ultraviolet light generated by the excimer lamp is incident, the optical filter transmitting ultraviolet light having a wavelength within a range of 190 nm or more and less than 240 nm and substantially not transmitting ultraviolet light having a wavelength within a range of 240 nm or more and less than 280 nm, in which a sealing pressure ratio of the halogen gas to the noble gas in the luminous gas sealed in the luminous tube is 2% or more and less than 5%.

The inactivation apparatus includes: an excimer lamp that includes a luminous tube, and a pair of electrodes, and generates ultraviolet light having a main emission wavelength band within a range of 190 nm or more and less than 240 nm in the luminous tube when a voltage is applied between the pair of electrodes; and an optical filter into which ultraviolet light generated by the excimer lamp is incident, the optical filter transmitting ultraviolet light having a wavelength within a range of 190 nm or more and less than 240 nm and substantially not transmitting ultraviolet light having a wavelength within a range of 240 nm or more and less than 280 nm, in which a sealing pressure ratio of the halogen gas to the noble gas in the luminous gas sealed in the luminous tube is 2% or more and less than 5%.