An excimer lamp includes a housing portion having a sealed internal space, an internal electrode, and a discharge gas with which the internal space is filled. One end side of the internal electrode is electrically connected to a power supply member provided with a metal foil electrically connected to the internal electrode and is sealed together with the power supply member to one end side of the housing portion via a sealing portion. The other end side of the internal electrode protrudes into the internal space. A protrusion length, being a length of the internal electrode in the internal space and a length from one end of the internal space to the other end of the internal electrode, is equal to or less than a length from the other end of the internal electrode to the other end of the internal space in a direction along the axis.

An excimer lamp includes a housing portion having a sealed internal space, an internal electrode, and a discharge gas with which the internal space is filled. One end side of the internal electrode is electrically connected to a power supply member provided with a metal foil electrically connected to the internal electrode and is sealed together with the power supply member to one end side of the housing portion via a sealing portion. The other end side of the internal electrode protrudes into the internal space. A protrusion length, being a length of the internal electrode in the internal space and a length from one end of the internal space to the other end of the internal electrode, is equal to or less than a length from the other end of the internal electrode to the other end of the internal space in a direction along the axis.

An ultraviolet irradiation device includes: a lamp house having at least one surface formed with a light extraction surface; an excimer lamp that is accommodated in the lamp house at a position apart from the light extraction surface in a first direction, the excimer lamp emitting ultraviolet light having a main emission wavelength belonging to a first wavelength band of 190 nm or more and 225 nm or less; a pair of electrodes that applies a voltage to a light-emitting tube of the excimer lamp; an optical filter disposed on the light extraction surface, and that substantially transmits the ultraviolet light having the first wavelength band and substantially fails to transmit ultraviolet light having a wavelength of 240 nm or more and 300 nm or less; and a light diffuser that is disposed between the excimer lamp and the optical filter in the lamp house in the first direction.

An ultraviolet irradiation device includes: a lamp house having at least one surface formed with a light extraction surface; an excimer lamp that is accommodated in the lamp house at a position apart from the light extraction surface in a first direction, the excimer lamp emitting ultraviolet light having a main emission wavelength belonging to a first wavelength band of 190 nm or more and 225 nm or less; a pair of electrodes that applies a voltage to a light-emitting tube of the excimer lamp; an optical filter disposed on the light extraction surface, and that substantially transmits the ultraviolet light having the first wavelength band and substantially fails to transmit ultraviolet light having a wavelength of 240 nm or more and 300 nm or less; and a light diffuser that is disposed between the excimer lamp and the optical filter in the lamp house in the first direction.

An electrodeless laser-driven light source includes a laser that generates a CW sustaining light. A pump laser generates pump light. A Q-switched laser crystal receives the pump light generated by the pump laser and generates pulsed laser light at an output in response to the generated pump light. A first optical element projects the pulsed laser light along a first axis to a breakdown region in a gas-filled bulb comprising an ionizing gas. A second optical element projects the CW sustaining light along a second axis to a CW plasma region in the gas-filled bulb comprising the ionizing gas. A detector detects plasma light generated by a CW plasma and generates a detection signal at an output. A controller generates control signals that control the pump light to the Q-switched laser crystal so as to extinguish the pulsed laser light within a time delay after the detection signal exceeds a threshold level.

An electrodeless laser-driven light source includes a laser that generates a CW sustaining light. A pump laser generates pump light. A Q-switched laser crystal receives the pump light generated by the pump laser and generates pulsed laser light at an output in response to the generated pump light. A first optical element projects the pulsed laser light along a first axis to a breakdown region in a gas-filled bulb comprising an ionizing gas. A second optical element projects the CW sustaining light along a second axis to a CW plasma region in the gas-filled bulb comprising the ionizing gas. A detector detects plasma light generated by a CW plasma and generates a detection signal at an output. A controller generates control signals that control the pump light to the Q-switched laser crystal so as to extinguish the pulsed laser light within a time delay after the detection signal exceeds a threshold level.

Provided is an ultraviolet irradiation device including an excimer lamp, a main emission wavelength of which belongs to a wavelength band of 190-230 nm (first wavelength band), the ultraviolet irradiation device that shows high startability. This ultraviolet irradiation device includes: a lamp house on at least one surface of which a light extraction surface is formed; an excimer lamp accommodated in the lamp house, the excimer lamp that emits ultraviolet light, a main emission wavelength of which belongs to a first wavelength band of 190-230 nm; and a start assist light source arranged in a position in which ultraviolet light, a main emission wavelength of which belongs to a second wavelength band of 250-300 nm, is capable of being irradiated to the excimer lamp.

Provided is an ultraviolet irradiation device including an excimer lamp, a main emission wavelength of which belongs to a wavelength band of 190-230 nm (first wavelength band), the ultraviolet irradiation device that shows high startability. This ultraviolet irradiation device includes: a lamp house on at least one surface of which a light extraction surface is formed; an excimer lamp accommodated in the lamp house, the excimer lamp that emits ultraviolet light, a main emission wavelength of which belongs to a first wavelength band of 190-230 nm; and a start assist light source arranged in a position in which ultraviolet light, a main emission wavelength of which belongs to a second wavelength band of 250-300 nm, is capable of being irradiated to the excimer lamp.

A Far UV radiation system including a Far UV radiation source and a high pass filter. The high pass filter having a cutoff wavelength of 234 nm-237 nm when measured at an incidence angle of zero degrees and adapted to substantially reduce UV C radiation emitted from the Far UV radiation source so that the Far UV radiation system does not emit substantial UV radiation in wavelengths longer than 240 nm. The Far UV radiation system may be adapted to substantially reduce UV C, UV B, and UV A radiation from the Far UV radiation source.

Provided is a portable IPL sterilizer comprising: a body partitioned into a central region and a peripheral region surrounding at least a portion of the central region; a xenon lamp light source for sterilization provided in the central region of the body; and a light-shielding comb part provided in the peripheral region of the body.