JPH0727771B2 - Low pressure mercury lamp - Google Patents

Description

TECHNICAL FIELD The present invention relates to a structure of a low-pressure mercury lamp, and more specifically, it provides a low-pressure mercury lamp which is particularly advantageous for use as an exposure light source. That is the purpose.

[Conventional technology]

In the photoexcitation process typified by photo-CVD, a light source that can irradiate a relatively large flat surface with a uniform illuminance distribution, that is, a surface light source is required.

However, the current mercury lamp, which is the light source for excitation,
Since it has a linear light source shape without exception, the required surface light source cannot be obtained as it is.

For this reason, when a surface light source is required, many straight tube mercury lamps are arranged in close parallel to each other or a single elongated mercury lamp is used to obtain a pseudo surface light source using a mercury lamp that is a linear light source. Means such as densely winding a spiral shape or bending and forming a dense spiral shape have been tried.

[Problems to be solved by the invention]

However, in the above-mentioned conventional example, since the circular tube body is basically the light emitting source, the light emitting surface of the pseudo surface light source to be formed follows the arc surface formed by the outer peripheral surface of the circular tube body. Since unevenness is inevitably formed, unevenness of illuminance occurs on the exposed surface, which is a completely flat surface, according to the unevenness of the light emitting surface, and a uniform illuminance distribution cannot be obtained.

In many cases, it is physically impossible to closely arrange the tubes of the mercury lamps that form the independent discharge paths, and the mercury lamps are arranged at regular intervals. As a result, the unevenness of the illuminance on the exposed surface becomes more remarkable.

Further, in order to obtain the maximum efficiency, the low-pressure mercury lamp is always assembled integrally with the cooling means. However, when a large number of mercury lamps are closely arranged in parallel, it is necessary to physically install the cooling means for each mercury lamp. However, even if the assembly of cooling means for individual mercury lamps can be achieved, the adjacent mercury lamps will affect each other thermally, and thus the required temperature control for the mercury lamps is almost impossible. It will be possible.

In short, the conventional technology forms a surface light source by combining a mercury lamp that is originally composed of a circular tube body that forms a linear light source, so that the light irradiation characteristics of the circular tube body that forms a linear light source will inevitably appear. Therefore, the light irradiation characteristic of the circular tube causes unevenness of the illuminance distribution on the exposed surface.

The present invention was devised to eliminate the above-mentioned problems in the conventional example, and it is a technical problem to configure a low-pressure mercury lamp with a flat plate and use this flat plate as an irradiation surface of the low-pressure mercury lamp. It is what

[Means for solving problems]

Hereinafter, the present invention will be described with reference to the drawings showing an embodiment of the present invention.

The means of the present invention comprises: a flat window plate 1 made of an electrically insulating material having a high transparency to the generated light; and a flat plate made of an electrically insulating material provided with a reflection function for the generated light. Having a back plate 2 arranged in parallel with the plate 1, the window plate 1 and the back plate 2 are hermetically connected to each other, and the window plate 1
The airtight space formed between the back plate 2 and the back plate 2 is provided with an elongated discharge path 5
To have a partition plate 3 made of an electrically insulating material for partitioning into, to have discharge electrodes 4 arranged at both ends of the discharge path 5, and to have a cooling function body 6 assembled and arranged on the outer surface of the back plate 2. is there.

[Action]

According to the present invention, as described above, since the sealed space formed between the window plate 1 and the back plate 2 which are flat plates serves as a discharge path, the light emitting surface of the low-pressure mercury lamp, which constitutes the window plate 1 itself, is provided. Therefore, the light emitting surface of the low-pressure mercury lamp thus constructed becomes a flat surface.

Also, a back plate 2 located behind the window plate 1 forming the light emitting surface.
Has a function of reflecting generated light,
All of the generated light rays are emitted to the window plate 1 side.

Further, since the cooling function body 6 is assembled and arranged on the outer surface of the back plate 2 which is a flat plate body, the assembling thereof is simple and the cooling function is exerted on the entire outer surface of the back plate 2. Therefore, the coldest portion 7 can be formed at any desired location of the discharge path 5 formed in a bent or curved shape.

〔Example〕

The following example shows a low-pressure mercury lamp configured to be used in a photoexcitation process. The window plate 1 has a high transparency to light having a wavelength of 184 nm and has a 2 mm thick synthetic quartz surface polished on both sides. Made of wood and used as back plate 2 as window plate 1
The same material is used, and a reflection film portion 2a having a multilayer film structure that efficiently reflects light having a wavelength of 184 nm is formed as a reflection function portion on the outer surface by sputtering.

The partition plate 3 is a transparent quartz plate having a thickness of about 1 mm.

In the embodiment shown in FIG. 1 and FIG. 2, the window plate 1 and the back plate 2 having the same square plate shape of 200 × 200 mm are hermetically sealed by the peripheral wall portion 3a of the partition plate 3 having a width of 10 mm between the peripheral portions thereof. By connecting, an airtight space is formed between the window plate 1 and the back plate 2,
The airtight space is partitioned by the partition wall portions 3b of the partition plate 3 arranged in a zigzag pattern at intervals of 10 mm to form a long and narrow inverted discharge path 5, and the electrodes 4 are attached to both ends of the discharge path 5. ing. The cooling function body 6 mounted on the outer surface of the back plate 2 has an inlet / outlet port 6b that forms an inlet / outlet port for cooling water as a cooling medium, and the entire outer surface of the back plate 2 is attached to the back plate 2 to form a water chamber. Is formed by a cooling frame 6a that forms one surface.

As described above, the cooling function body 6 is configured to be able to control and cool the entire outer surface of the back plate 2, and is arranged to face the entire discharge path 5, so that the optimum inside of the discharge path 5 is obtained. In order to obtain a sufficient mercury vapor pressure, the coldest portion 7 can be formed at a plurality of appropriate desired locations of the elongated discharge path 5, and therefore a light emission operation by uniform discharge is obtained in the entire elongated discharge path 5. be able to.

The effective discharge length of the examples of FIGS. 1 and 2 was 2000 mm, and a surface emission distribution having excellent flatness could be obtained at a total input power of 1000 W and an input density of 5 W / cm ² .

The embodiment shown in FIGS. 3 and 4 is an example in which a spiral discharge wall 5 having a width of 10 mm is formed between a window plate 1 and a back plate 2 by a partition plate 3 formed in a spiral shape. In comparison with the embodiment shown in FIG. 1, the embodiment shown in FIG.
While it is possible to obtain a better discharge state, the structure of the cooling function body 6 becomes slightly complicated, and one electrode 4 is located at the center of the light emitting surface, so the emission intensity is reduced at this one electrode 4 portion. Appropriate measures must be taken to prevent this.

The embodiment shown in FIG. 5 shows that a plurality of discharge paths 5 can be formed in parallel in a combination of a pair of window plate 1 and back plate 2, and when the input power is small, or On the contrary, it is effective when it is desired to obtain a surface light source having a vast light emitting surface.

As the partition plate 3, it is advantageous to use a partition plate having a high transmissivity to the generated light beam, like the window plate 1. This is because the light rays generated in the adjacent discharge paths 5 are mixed with each other, so that the emitted light rays with more uniform illuminance can be obtained.

〔The invention's effect〕

As is clear from the above description, since the present invention can irradiate a flat irradiation surface with light rays with a uniform illuminance distribution, it is possible to directly and extremely achieve the exposure of a flat exposure object. Therefore, the structure of the light source function part in the exposure equipment can be made extremely simple, and the amount of irradiation light can be doubled by the structure of the mercury lamp itself. The amount of irradiation light can be obtained, and the cooling function part is integrated with the lamp body and the cooling function part faces the entire discharge path, so temperature control for obtaining the optimum mercury vapor pressure is simple. It is possible to obtain accurate results, and therefore, it is possible to obtain a number of excellent effects such as always obtaining an efficient discharge operation.

[Brief description of drawings]

1 and 2 show the structure of an embodiment of a low-pressure mercury lamp according to the present invention. FIG. 1 is a front view seen from the window plate side, and FIG. 2 is II in FIG. FIG. 6 is a vertical cross-sectional view taken along the line of FIG. FIGS. 3 and 4 show the structure of another embodiment of the low-pressure mercury lamp according to the present invention. FIG. 3 is a front view seen from the window plate side, and FIG. 4 is II- in FIG. It is a longitudinal cross-sectional view taken along the line II of FIG. FIG. 5 is a front view seen from the window plate side showing the configuration of still another embodiment of the low-pressure mercury lamp according to the present invention. DESCRIPTION OF SYMBOLS 1; Window plate, 2; Back plate, 3; Partition plate, 3a; Peripheral wall portion, 3b; Partition wall portion, 4; Electrode, 5; Discharge path, 6; Cooling function body, 6a; Cooling frame body, 6
b; entrance / exit port; 7; coldest part.

Claims (1)

[Claims] 1. A flat window plate (1) made of an electrically insulating material having a high transparency to a generated light beam, and a flat plate made of an electrically insulating material having a function of reflecting the generated light beam, wherein Back plate (2) arranged parallel to the plate (1)
And an electrically insulating material for airtightly connecting the window plate (1) and the back plate (2) and partitioning an airtight space formed between the window plate 1 and the back plate 2 into an elongated discharge path 5. Made of a partition plate 3, discharge electrodes (4) arranged at both ends of a discharge path (5) formed by the partition plate (3), and a cooling unit assembled on the outer surface of the back plate (2). Function body (6)
And a low pressure mercury lamp.