Ushio Denki Kabushiki Kaisha

Kabushiki Kaisha Nikon

Masanori Sugihara

Yukio Yasuda

Akiyasu Yamaguchi

Naohisa Ikeda

Takashi Mori

Tatsushi Igarashi

Akira Miyaji

Kenzo Kai

Yasuo Oonishi

Shinkichi Morimoto

Shouichi Mayama

Yoshiharu Kamatani

Short-arc discharge lamp designed to minimize the phenomenon of foil floating between the metal foil located in the foil sealing area and the sealing quartz component that is in contact with the inside of the metal foil so as to prevent cracks from forming in the foil sealing area, gas leakage from the lamp, and premature breaking of the lamp. The short-arc discharge lamp includes electrodes which are located in an emission space, a metal foil electrically connected to the electrodes, a quartz tube part which surrounds the metal foil, a sealing quartz component in contact with the inside of the metal foil, and a metallic component inserted into the sealing quartz component and electrically connected to the metal foil. The foil sealing area is formed from the metal foil, the quartz tube, and the sealing quartz component, which are sealed against one another. By the sealing action of the foil sealing area, sealing of the emission space is ensured. The short-arc discharge lamp has an electrical input power rating of greater than or equal to 4 kW and an operating pressure during luminous operation of greater than or equal to 2&times;10 Pa, and is operated using direct current. The above-mentioned characteristics are achieved in that the length of the area of a metallic component inserted into the sealing quartz component is greater than or equal to roughly 40% of the total length of the sealing quartz component.

Short-arc discharge lamp

A short-arc discharge lamp ( ) including a light-emitting tube ( ) having at least 15 mg/cc of mercury sealed therein, an anode ( ) and cathode ( ) facing each other and disposed within the light-emitting tube ( ), and a heat-release layer ( ) covering a substantial portion of an outer surface of the cathode ( ) so that when the short-arc discharge lamp ( ) is provided with electricity having a current value of at least 50 A, an inter-electrode power value defined by a ratio Y/X is at least 500 W/mm, X being defined as a distance in millimeters between the anode ( ) and the cathode ( ), and Y being defined as an input power in Watts provided to the short-arc discharge lamp ( ).

To devise a mercury lamp of the short arc type with high power in which an arc tube can be kept unfouled over a long time and the demand for an increase in the amount of radiation can be met, in a quartz arc tube, a cathode and an anode are disposed opposite one another and the arc tube is filled with mercury and a rare gas. At least argon (Ar) and/or krypton (Kr) in an amount from 1.0 to 8 atm at room temperature is added as the rare gas. The amount depends on the value of ((Wd).sup.1/2 /R) where R is half the maximum diameter of the bulb in cm, d is the thickness of the bulb in cm, and W the input power supplied to the lamp in kW.

Mercury lamp of the short arc type

A discharge lamp of the short arc type with good light intensity stability in which arc fluctuation is suppressed is achieved, according to the invention by providing a discharge lamp of the short arc type which has an arc tube which surrounds the discharge space, hermetically sealed portions on the two ends of the arc tube, a cathode and an anode which are arranged opposite one another in the arc tube and which is operated such that the cathode is pointed upward, in by the cathode being supported by an inner lead which is held securely by the hermetically sealed portion, the outside diameter of the cathode being greater than the outside diameter of the inner lead, and by the relationship L.gtoreq.2.5D being satisfied, where D is the outside diameter of the cathode (mm) and L is the axial length of the cathode (mm).

Cathode structure for short arc type discharge lamp

A mercury lamp of the short arc type with a high degree of maintenance of irradiance is achieved in a mercury lamp of the short arc type by the cathode containing thorium oxide and having a tungsten carbide layer on its surface except at tip end area, by at least one of the cathode or anode being provided with metallic tantalum, and by the condition 1.56.ltoreq.VT/SC being satisfied, where SC is the area of the tungsten carbide layer (cm.sup.2) and VT is the volume of the metallic tantalum (mm.sup.3). Alternatively, a high degree of maintenance of irradiance can be achieved in a mercury lamp of the short arc type by the condition 0.043.ltoreq.VT/VW being satisfied, where VW is the volume of the anode (cm.sup.3) and VT is the volume of the tantalum in the lamp bulb (mm.sup.3).

A mercury lamp of the short arc type with high radiant efficiency which satisfies the demand for an increase of the radiation amount of the light source, by suppressing the motion of the bright spot in the vicinity of the cathode tip suppresses the flickering of the irradiance and thus increases the arc stability, is achieved in a mercury lamp of the short arc type in which within an arc tube mercury and at least one rare gas are encapsulated, by either at least Ar being filled as the rare gas at an filling pressure of from 1 to 8 atm, and by the current density in the tip area of the cathode being 10 to 250 A/mm.sup.2 or alternatively, at least Kr being filled as the rare gas at an filling pressure of from 1 to 8 atm, and the current density in the tip area of the cathode being 10 to 310 A/mm.sup.2 during operation of the lamp. By operation of the above described lamp in a vertical orientation with the anode positioned above the cathode a further contribution to the attainment of the noted advantages is achieved.

Mercury lamp of the short arc type and method for operation thereof

A lamp device in which the lamp can be reliably held and moved for adjustment of its position with respect to a concave reflector without being damaged, and in which the position of the lamp can be adjusted with high accuracy is achieved by providing a concave reflector with a cylindrical neck in its center bottom area and a lamp in which there is a hermetically sealed portion on at least one of its ends, and which is arranged with the hermetically sealed portion inserted through the neck of the concave reflector. Furthermore, according to the invention, the lamp device has a lamp base which is attached on the hermetically sealed portion of the lamp, and which extends in the axial direction of the lamp, and has a sleeve component formed of a cylindrical reflector holding portion and a cylindrical lamp base holding portion that are integrally united as one-piece, and in which in the reflector holding portion the neck of the concave reflector is attached. According to the invention, the lamp base is attached in the lamp base holding portion of the sleeve component with an adhesive in the state in which it projects from the outer end thereof.

Lamp device

A cadmium/inert gas discharge lamp of the short arc type, which suppresses an unnecessary emission upstream and downstream of the necessary emission spectra in a wavelength range of 210 to 230 nm, achieves a high efficiency of the emission spectra in the range 210 to 230 nm and can be used in very satisfactory manner for industrial applications. Also, a highly efficient projection exposure device through the incorporation of a cadmium/rare gas discharge lamp of the short arc type having good emission spectrum characteristics in the wavelength range 210 to 230 nm, which can transmit in projecting manner fine image patterns with a large depth of focus. The cadmium/rare gas discharge lamp of the short arc type is arranged within a temperature-regulated quartz bulb, and is provided with a pair of adjacently facing electrodes, together with inert gas selected from xenon, krypton, argon, neon or mixtures of them. Metal cadmium with a pressure of 14 to 200 kPa is encapsulated in the tube in a stationary lighting operation. The lamp is operated in such a way that J/P, i.e. the ratio between a discharge current in a stationary lighting operation J (A) and a cadmium pressure in a stationary lighting operation P (kPa) is in a range 0.13 to 15. Also, a projection exposure device, which has the above-described discharge lamp and a power supply for carrying out the lighting operation of the discharge lamp under the above-described condtions.

Growing community of inventors

Himeji, Japan

Masanori Sugihara