JPS60105159A - Light source for exposure device - Google Patents

Abstract

PURPOSE:To obtain a light source for an exposure device which can achieve a high potential gradient and a high luminous efficiency by covering the entire outer surface of an ultrahigh-pressure mercury lamp by an ultraviolet-ray-deflecting body and providing the reflective body with an opening. CONSTITUTION:A reflective body 2 which is made of a metal such as Al, Rh, SUS or Cr, used as an exposure light source and greatly reflects light with the emission spectrum of within the range of 300-500nm is installed on the outer surface of an ultrahigh-pressure mercury lamp 1. In addition, an opening 3 is formed in the reflective body 2, thereby making a light source for an exposure device. As a result, the emission from a plasma arc 4 installed in the lamp 1 passes through an ionic layer 5 before undergoing regular reflection on the inner surface of the reflective body 2, then the reflected light is returned to the lamp 1. At the same time, the reflected light can be taken outside the light source through the opening 3. Consequently it is possible to produce exposure light which has a high potential gradient and a great luminous intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a light source for an exposure apparatus, particularly to improving the light emitting efficiency of the light source.

[Background of the invention]

The light emitting efficiency of an ultra-high pressure mercury lamp, which is generally used as a light source for exposure equipment, is determined by the potential gradient of the plasma arc (anode/cathode potential difference/arc length: V/W).

FIG. 1 shows the relationship between the emission spectrum and irradiance of an ultra-high pressure mercury lamp (hereinafter referred to as a lamp). In the same figure, A is 8 for a lamp with an arc length of 25III++.
Showing the emission spectrum when applying a voltage of 50v,
The potential gradient at this time is 34 V/fMI. Also,
B shows the emission spectrum when 750V is applied to a lamp with an arc length of 15mm, and the potential gradient at this time is 50V.
/mm. Therefore, from the comparison between A and B in the same figure,
It is clear that the emission intensity differs depending on the difference in potential gradient. In addition, for example, in the case of a png arc water-cooled ultra-high pressure mercury lamp, this potential gradient is 10 for an arc length of 25 wM.
A voltage of 0 OV is considered to be the limit value for bursting, and the potential gradient in this case is 40 V/m.

However, in order to improve the luminous efficiency of the lamp in response to the recent demand for high-density dot-type fluorescent surface formation, the potential gradient f 60 V/wn of the water-cooled lamp described above has been increased.

In other words, if an input of 150° is applied, there is a problem that the plasma arc is not thick and is instantly destroyed by contact between the lamp tube wall and other members.

[Purpose of the invention]

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its main purpose is to provide a light source for an exposure device that can obtain high luminous efficiency by increasing the potential gradient. .

[Summary of the invention]

In order to achieve such an object, the present invention covers the entire outer periphery of the lamp with an ultraviolet reflector and provides an opening in a part of the reflector to obtain light with high luminous efficiency. It is.

[Embodiments of the invention]

Next, embodiments of the present invention will be described in detail using the drawings.

FIG. 2 is a cross-sectional configuration diagram of essential parts showing an embodiment of a light source for an exposure apparatus according to the present invention. In the figure, 1 is an ultra-high-pressure mercury lamp (lamp), and 2 is a reflector made of a metal material with high ultraviolet reflectance and placed around the outer periphery of the lamp 1. This reflector 2 is used as an exposure light source. Emission spectrum between 300 and 500 gates Idl, >Rh) 5US)
Cr)Ni)Ag)Au)B[1BM] Since a large reflected light intensity can be obtained in this order, it is preferable to use these metal materials. Reference numeral 3 denotes an opening that is provided in a part of the reflector 2 and takes out the light reflected on the inner surfaces of the lamp 1 and the reflector 2 to the outside.

In such a configuration, since the ultraviolet light reflector 2 is disposed around the outer circumference of the lamp 1, the light emitted from the plasma arc 4 inside the lamp 1 is partially absorbed by the inner surface of the reflector 2 through the ion layer 5. It is specularly reflected, and the reflected light is returned to the lamp 1 and taken out from the opening 3.

Note that the present invention is not limited to the embodiments described above, and it goes without saying that various modifications can be made without departing from the gist of the present invention. For example, the same effect can be obtained with the structure shown in Fig. 3 as a long arc light source, and the structure shown in Fig. 4 as a short arc light source.
In the short arc light source shown in the figure, the spherical pulp is covered with a spherical ultraviolet light reflector, rather than the elliptical pulp commonly available on the market, to increase the light intensity and prevent fluctuations in the alignment. It is extremely effective.

FIG. 5 shows the results of actually measuring the emission spectrum of a light source using an ultraviolet light reflector made of Rh system, which is completely unaffected by ultraviolet light deterioration, etc., in the above-mentioned embodiments. In the same figure,
In the case of point vision with potential gradient 'f: 36 V/mm (curve A), the atomic spectrum lines at 365 mm, 405 mm, and 436 mm are tb, with a potential gradient of 60 V/mm (curve B)
However, it is clear that an increase in light intensity is observed in broad band regions other than the atomic spectrum.

Furthermore, the sensitivity range of photosensitizers used in color cathode ray tubes and the like is the wavelength range shown in Figure 5, and when this is converted into the wavelength range inputted to the lamp, the same energy as that of the black matrix bulb is obtained. The increase was approximately 1.5 times for dry process balls, approximately 1.8 times for dry process balls, and approximately 2 times for slurry balls.

〔Effect of the invention〕

As described above, the light source according to the present invention has an extremely excellent ζ effect in that raft light with a large emission intensity can be obtained with a given potential gradient.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the relationship between the emission spectrum and irradiance of a lamp, Fig. 2 is a cross-sectional configuration diagram showing an embodiment of a light source for an exposure device according to the present invention, and Figs. FIG. 15 is a perspective view of a main part showing another embodiment of a light source for an exposure device, and is a diagram showing the relationship between the emission spectrum and the irradiance of the light source for an exposure device according to the present invention.

Claims (1)

[Claims] 1. The entire outer periphery of a lamp that obtains light output by plasma discharge is covered with an ultraviolet reflector, and a part of the reflector is provided with an opening for extracting the light output. Light source for exposure equipment. 2. The light source for an exposure apparatus according to claim 1, wherein the reflector is a metal member that provides a high emission spectrum only in a specific wavelength range.