JP2730004B2 - Light source device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device that collects light from a short arc discharge lamp using a condenser mirror and uses the collected light.

[Related Art] Various processes such as curing and drying of adhesives, paints, inks, resists, and the like, and exposure of a mask pattern on a semiconductor wafer are performed by light irradiation. A short arc discharge lamp such as a xenon lamp or an ultra-high pressure mercury lamp is used for the light irradiation.

FIG. 4 is an explanatory view showing a schematic configuration of a main part of a light source device using a short arc type discharge lamp, and 8 is a lamp body.
The lamp body 8 is an ultra-high pressure mercury lamp (hereinafter, referred to as a lamp), which is a short arc type discharge lamp as a light source.
An elliptical converging mirror 2, a reflecting mirror 3, an integrator lens 4, and an image forming lens 6 for condensing the light. Reference numeral 7 denotes a position adjusting mechanism for the lamp 1. When mounting the lamp 1, the center of the arc of the lamp 1 is arranged at the second focal point of the elliptical focusing mirror 2, and the light from the lamp 1 via the elliptical focusing mirror 2 is reflected by the reflecting mirror 3. The light is reflected and enters the integrator lens 4 (which is located at the second focal point of the elliptical condenser mirror 2).

Therefore, it is necessary to install the lamp 1 so that the center of the arc is located at the first focal point of the elliptical condenser mirror 2. Otherwise, the light of the lamp 1 cannot not only collect the light to the integrator lens 4 with high accuracy, but also
The irradiation surface 9 cannot be uniformly irradiated with light at a high illuminance.

Therefore, it is necessary to adjust the center of the arc of the lamp 1 so as to be at the first focal point of the elliptical focusing mirror 2.

When adjusting the lamp 1, after removing the upper lid of the lamp body 8,
An operator puts his hand in the lamp body 8 and operates the position adjustment mechanism 7 to move the lamp 1 in the height direction and the vertical and horizontal directions on the plane. At that time, the position of the lamp 1 is
The following two methods have been considered as a method for confirming whether or not the discharge lamp is accurately positioned at the desired position, that is, a conventional method for monitoring the arc position of a discharge lamp.

As shown in FIG. 4, a light receiver of an irradiation monitor 10 is provided on an irradiation surface 9.
With the position 10a, the position of the lamp 1 is monitored by monitoring the illuminance distribution of the irradiation surface 9 while adjusting the position of the lamp 1 by the position adjusting mechanism 7 to know the position of the arc of the lamp 1. Then, when the illuminance is maximum and the illuminance distribution becomes uniform, it can be confirmed that the arc is at the position of the first focal point of the elliptical converging mirror 2.

As shown in FIG. 5, the arc image of the lamp 1 is converted to the holes 2a and 2b of the elliptical converging mirror 2 and the lenses 11a, 12a, 14a, 15a and 11
b, 12b, 14b, 15b, and a lens system composed of mirrors 13a and 13b for turning, monitor while enlarging and forming images on two screens 16a (X-axis, Z-axis) and 16b with a crosshair formed at the center, The position adjusting mechanism of the lamp 1 is operated to form an image of the arc at the center of the two screens with cross hairs, and the arc is positioned at the first focal point.

[Problems to be Solved by the Invention] As described above, in the conventional method of monitoring the arc position of a discharge lamp, in the above-described method, the irradiation surface is located inside the mechanical structure of the apparatus. In some cases, the receiver cannot be placed directly on the irradiation surface, and it is difficult to monitor on the irradiation surface.

Even if the receiver can be placed on the irradiation surface, adjust the position while looking at the receiver because the operating part of the position adjustment mechanism of the discharge lamp and the irradiation surface are far apart. Is difficult.

Also, in the above method, the arc image is usually about 3 _mm.
Since it is difficult to project the image on the screen at the same magnification and visually monitor it, it is necessary to magnify the arc image by, for example, about 5 times. Therefore, it is necessary to magnify and form the arc image. .

Therefore, in order to enlarge and combine the arc images, a large number of lenses and a folding mirror are required. In addition, the optical path length for each lens becomes large, and the device becomes large, and a large number of mirrors are formed. There is a problem that adjustment at the time of assembly by using a lens or a mirror is difficult.

The present invention has been made in order to solve such a conventional problem, and it is possible to perform monitoring without placing a light receiver on an irradiation surface, and because the number of lenses and mirrors required for arc monitoring is small, the optical path length is reduced. It is an object of the present invention to provide a light source device that is short, small, and easily adjusted during assembly.

[Means for Solving the Problems] In order to achieve the above object, a light source device according to the present invention uses a focal point position of a condenser mirror as an object point and is orthogonal to each other in a plane perpendicular to a tube axis direction of a discharge lamp. Two or more imaging optical systems having an optical axis, a photoelectric conversion element provided at a position of an image point of the imaging optical system and having an incident surface divided into a plurality of segments, and an electric signal from each segment , And display means for displaying the result of the comparison by the comparing means.

[Operation] In the light source device having the above configuration, the comparison result displayed on the display means indicates the position of the arc of the discharge lamp with respect to the focal point of the condenser mirror.

Embodiment FIG. 1A is a schematic explanatory view of a main part of a light source device according to an embodiment of the present invention, and FIG. 1B is a diagram illustrating each of the imaging optical systems in FIG. In the figure for explaining the optical axis, the tube axis direction is defined as the Z axis, and a plane perpendicular to the Z axis is defined as a plane including the X axis and the Y axis. L ₁ is a first imaging optical system, L ₂ represents the second imaging optical system, respectively. Fig. 2 (a),
(B) is an explanatory view of the incident surfaces of two photoelectric conversion elements used in the arc monitor system of the light source device of FIG. 1.

In Figure 1, the optical axis of the imaging optical system L ₁ coincides with the Y-axis, the optical axis of the imaging optical system L ₂ coincides with the X-axis, X-axis and Y-axis are orthogonal to each other.

In FIG. 1 and FIG. 2, the arc of the lamp 1 is first formed with respect to the X-axis and Z-axis directions from the hole 2a of the elliptical converging mirror 2 via a pinhole plate 17a having a dimming function. 1
After passing through 8a, it is reflected by the mirror 19a for turning back,
The light passes through 0a, is incident on the photoelectric conversion element 20a, and is projected.
Similarly to the X-axis and Z-axis directions, in the Y-axis direction, a pinhole plate 17b, an imaging lens 18
b, the light enters the photoelectric conversion element 20b via the folding mirror 19b and the filter 30b and is projected.

Incidentally, in the light source device shown in FIG. 1, the arc length of the lamp 1 is about 3 _mm , but the holes 2a and 2b of the elliptical converging mirror 2 are provided.
Since the light emitted from the lens is very strong, guiding all the light beams from the holes 2a and 2b to the imaging optical system will damage each optical component and the photoelectric conversion elements 20a and 20b. Board 1
7a and 17b are provided to reduce the light and reduce the light flux from the elliptical condenser mirror 2.

Further, after being converted into an electric signal by the photoelectric conversion elements 20a and 20b, a signal processing unit 21 disposed in the light source device of FIG.
The current-voltage conversion is performed, the voltage value is further compared by the comparing means, and based on the output, the arcing is performed by the display means 22 comprising a zero-center voltmeter for each of the X, Y, and Z axes. An indication about the position is made. The details are described below.

In the present embodiment, the photoelectric conversion elements 20a and 20b use a photodiode, and the incident surface thereof has four segments D ₁ and D which are electrically insulated from each other as shown in FIG.
_2, D _3, D ₄ and _{D 5, D 6, D 7} , D 8, made of. Accordingly, the photoelectric conversion elements 20a, 20b are segments _{D 1, D 2, D 3} , D 4 and _{D 5, D 6, D 7} , D 8
Photodiodes D ₁₀ , D ₂₀ , D ₃₀ , D ₄₀ and D
₅₀ , D ₆₀ , D ₇₀ , D ₈₀
The origin 0 of each of a and 20b is located on each optical axis.
Each of the photoelectric conversion elements 20a and 20b is set so that each incident surface is perpendicular to each optical axis. Such a configuration of the photoelectric conversion elements 20a, with respect to 20b, when the arc of the lamp 1 is not correctly positioned at the focal point of the elliptical condensing mirror 2, each of the segments D ₁ and D _3, D ₂ and D ₄ or will be a difference in the light beam is generated which strikes the D ₅ and D _7, the difference of the light is converted into a current, converted by the signal processing circuit 21 into a voltage, the photodiode D ₁₀
And in the D _30, D ₂₀ and D ₄₀ or D ₅₀ and D _70, the difference voltage based on the difference between the photocurrent is generated, monitored and displayed on the display means 22 compares the difference. Conversely, when the arc is correctly positioned at the focal point, there is no difference between the current and the voltage, and therefore, the display means 22 indicates 0 to that effect.

Incidentally, in this embodiment, as not relevant with regard since the photoelectric conversion element 20a is monitored only the displacement of the arc relative to the Y-axis direction segments D ₆ and D ₈ (photodiode D _60, D ₈₀₎ Are dealing.

The light of the arc is converted to a photoelectric conversion element using FIG.
Processing after photoelectric conversion in 20a and 20b will be described.

From the arc is the focal point of the elliptical condensing mirror 2, for example if the shift even slightly in the X-axis direction, a difference in current of the photodiode D ₁₀ and D ₃₀ is generated, a current - converted by the voltage conversion circuit 211 into a voltage, the comparator circuit An output is provided at 217, and this output causes the needle of the voltmeter at the zero center of the display means 22a in the X-axis direction to swing rightward or leftward, thereby displaying the positional deviation. Similarly,
The displacements in the Y-axis direction and the Z-axis direction are also displayed on the display means 22c and 22b in the respective directions.
Adjust the displacement.

When the arc of the lamp is correctly positioned at the focal point of the condenser with respect to each of the X-axis, Y-axis, and Z-axis, the display means in the X-axis direction, the Y-axis direction, and the Z-axis direction. Of course, the needle of the voltmeter at the zero center is set to point to zero. The display unit may be a normal zero-left display unit, but a zero-center display unit is preferable because the direction of the deviation can be determined.

Further, the X-axis, the Y-axis, and the Z-axis may be independently monitored using another photoelectric conversion element and an imaging optical system.

[Effects of the Invention] As described above, the light source device according to the present invention includes:
Two or more imaging optical systems having optical axes orthogonal to each other in a plane perpendicular to the tube axis direction of the discharge lamp with the positions of the focal points of the condenser mirrors as object points, and the positions of the image points of the imaging optical systems A photoelectric conversion element having an incident surface divided into a plurality of segments, comparison means for comparing electric signals from each segment, and display means for displaying a result of comparison by the comparison means. There is no need to directly place the light on the irradiation surface of the light receiver of the illuminance monitor, and furthermore, the number of lenses and mirrors can be reduced and the optical path length can be shortened, so that the apparatus can be downsized, and thus the assembly of the arc monitoring mechanism can be performed. Easy.

[Brief description of the drawings]

FIG. 1 (a) is a schematic explanatory view of a main part of a light source device according to an embodiment of the present invention, and FIG. 1 (b) is for explaining each optical axis of the imaging optical system of FIG. 1 (a). FIGS. 2 (a) and 2 (b) are explanatory diagrams of incident surfaces of two photoelectric conversion elements used in FIG. 1, and FIG. 3 is a photoelectric conversion element and a signal processing circuit used in FIG. And a circuit block diagram for explaining the display section in terms of an electric circuit. FIG. 4 is an explanatory view showing a schematic configuration of a main part of a light irradiation apparatus using a short arc type discharge lamp. FIG. 3 is an explanatory view schematically showing a monitor device of FIG. In the figure. 1: Lamp, 2: Elliptical condenser mirror 2a, 2b: Hole 7: Discharge lamp position adjustment mechanism 17a, 17b: Pinhole plate 18a, 18b: Imaging lens 19a, 19b: Mirror 20a, 20b: Photoelectric conversion element 21 : Signal processing circuit 22: Display means 30a, 30b: Filter

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-109461 (JP, A) JP-A-58-195825 (JP, A)

Claims (1)

(57) [Claims] 1. A light source device comprising a short arc type discharge lamp, a condenser mirror in which an arc of the discharge lamp is to be disposed at a focal point thereof, and a position adjusting mechanism of the discharge lamp, wherein a focal point of the condenser mirror is provided. Two or more imaging optical systems having optical axes orthogonal to each other in a plane perpendicular to the tube axis direction of the discharge lamp with the position as an object point, and a plurality of imaging optical systems are provided at the positions of the image points of the imaging optical system; A light source comprising: a photoelectric conversion element having an incident surface divided into segments; comparing means for comparing electric signals from each segment; and display means for displaying a result of the comparison by the comparing means. apparatus.