Electric heating – Metal heating – By arc
Reexamination Certificate
2001-10-04
2003-09-30
Dynn, Tom (Department: 1725)
Electric heating
Metal heating
By arc
Reexamination Certificate
active
06627843
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a casing for a laser device, an inside of which laser light passes through, a production method and cleaning method of the same.
BACKGROUND ART
A cleaning device for cleaning optical components by radiating laser light is conventionally known, and it is disclosed, for example, in Japanese Patent Application Laid-open No. 2000-82856.
FIG. 6
shows the cleaning device disclosed in Japanese Patent Application Laid-open No. 2000-82856, and the prior art will be explained below based on FIG.
6
.
In
FIG. 6
, the cleaning device includes a laser oscillator
101
for oscillating cleaning laser light
102
having a wavelength of an ultraviolet range, a housing chamber
103
for housing an optical component
104
, a gas introduction mechanism
105
for supplying a gas into the housing chamber
103
, and a gas exhaust mechanism
106
for exhausting the gas inside the housing chamber
103
.
On cleaning, the optical component
104
is placed in the hermetically sealed housing chamber
103
, and while an oxygen gas is being introduced into the housing chamber
103
from the gas introduction mechanism
105
, the oxygen gas is exhausted by the gas exhaust mechanism
106
. Subsequently, the cleaning laser light
102
oscillated from the laser oscillator
101
is shaped in beam shaping means
108
, and is radiated to the optical component
104
via windows
107
and
107
. As a result, ozone and oxygen radicals generate from oxygen, and contaminants such as organic matters and the like adhering to the optical component
104
undergo oxidative decomposition and are discharged, whereby the optical component
104
is cleaned. By performing the cleaning as described above, transmittance of the optical component
104
is increased, and its life is increased.
However, the prior art disclosed in the aforementioned Japanese Patent Application Laid-open No. 2000-82856 has the following disadvantage.
FIG. 7
shows a schematic block diagram of an excimer laser device
109
. The excimer laser device
109
includes a laser chamber
112
, a front mirror
115
, a band-narrowing unit
120
for narrowing a bandwidth of laser light
111
, and a monitor module
116
for measuring properties of the laser light
111
. The band-narrowing unit
120
includes a band-narrowing box
121
, and an optical component
113
is placed therein. The monitor module
116
includes a monitor box
117
, and an optical component
114
is placed therein. Further, a light path of the laser light
111
is covered with a cover
119
for preventing the laser light
111
from filtering outside. Hereinafter, the monitor box
117
, the cover
119
and the band-narrowing box
121
for covering the light path of the laser light
111
are generally referred to as the casings
117
,
119
, and
121
.
The laser light
111
is irregularly reflected at surfaces of the optical components
113
and
114
or refracted at insides thereof, and strikes inner walls of the casings
117
,
119
and
121
. In this situation, contaminants such as organic matters and the like also adhere to the inner walls of the casings
117
,
119
and
121
. Consequently, there arises the disadvantage that the contaminants adhering to the inner walls of the casings
117
,
119
and
121
chemically react and are vaporized to adhere to the optical components
113
and
114
, thereby contaminating and damaging them.
In addition, the inner walls of the casings
117
,
119
and
121
have larger surface area as compared with the optical components
113
and
114
, and an amount of adhering contaminants is larger. Accordingly, there arises the necessity to not only clean the optical components
113
and
114
but also remove the contaminants from the inner walls of the casings
117
,
119
and
121
. Furthermore, optical component holders not shown for moving and fixing the optical components
113
and
114
to set optical axis are placed inside the casings
117
,
119
and
121
. The optical component holders are complicated in their shapes and have large surface areas, and a lot of contaminants are also adhering to their surfaces. Consequently, the optical component holders also need to be cleaned.
In the prior art, an article to be cleaned is put into the housing chamber
103
, and then is radiated with the cleaning laser light
102
. However, the casings
117
,
119
and
121
are much larger as compared with the optical components
113
and
114
, and therefore the huge housing chamber
103
is required to house them. In addition, coatings for keeping fine appearance are applied to or seals and the like for calling attention to how to use are stuck on outer walls of the casings
117
,
119
and
121
. Accordingly, even if the casings
117
,
119
and
121
are put into the housing chamber
103
and are radiated with laser light, a large quantity of organic matters generate from the outer walls, whereby the inner walls and the optical components
113
and
114
inside them are contaminated and damaged.
Further, according to the prior art, oxygen is fed into the housing chamber
103
and the cleaning laser light
102
is radiated. Components used in an F2 laser device need to be cleaned by an F2 molecular laser light oscillated from the F2 laser device or cleaning laser light of a shorter wavelength with higher light quantum energy. This is because even if the casings
117
,
119
and
121
are cleaned by cleaning laser light of a longer wavelength, if they are radiated with the F2 molecular laser light with higher light quantum energy again, contaminants generate therefrom.
However, the F2 molecular laser light is absorbed in oxygen very well and attenuated. Therefore, if the F2 molecular laser light is used as the cleaning laser light
102
, the cleaning laser light
102
sometimes does not reach the inner walls of the casings
117
,
119
and
121
in the atmosphere containing oxygen, and thus the effect of cleaning is reduced. Specifically, in the air or in an oxygen atmosphere, it is difficult to use the F2 molecular laser light as the cleaning laser light
102
and thus it is difficult to apply the prior art to the components of the F2 laser devices.
SUMMARY OF THE INVENTION
The present invention is made in view of the above-described disadvantage, and its object is to provide a casing for a laser device, in which contaminants do not generate even if laser light is radiated, a production method and a cleaning method of the same.
In order to attain the above-described object, a casing for a laser device according to the present invention is a casing for a laser device, an inside of which laser light passes through, and has a configuration in that
the inside is previously radiated with cleaning laser light.
According to the above configuration, contaminants adhering to an inner wall of the casing and components therein such as optical component holders and the like can be isolated by radiation of the cleaning laser light. Accordingly, by removing the isolated contaminants, the inside of the casing can be cleaned. Specifically, when the casing is incorporated into the laser device, even if the inside of the casing is radiated with laser light, generation of contaminants is reduced. As a result, it hardly happens that the optical components placed in the inside of the casing are contaminated and damaged, thus reducing the occurrence of power reduction of the laser light and increasing the lives of the optical components.
Further, in the casing for the laser device, the inside may be purged with a predetermined purge gas at a time of the radiation of the cleaning laser light.
According to the above configuration, at the time of the radiation of the cleaning laser light, the purge gas is exhausted, whereby the casing has the isolated contaminants exhausted form the inside. Accordingly, the casing with the inside being clean is provided.
A method of producing a casing for a laser device according to the present invention is
a method of producing a casing for a laser device, an inside of which laser light passes through, and
Itakura Yasuo
Wakabayashi Osamu
Yoshida Fumika
Arms Komatsu Ltd.
Armstrong Westerman & Hattori, LLP.
Dynn Tom
Johnson Jonathan
LandOfFree
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