JPH10144260A - Ultra-high-pressure mercury lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To radiate a large quantity of ultraviolet rays without reducing the ultraviolet rays in a short wavelength band, and prevent the generation of a stain in an inner wall of a tube by changing the shape of a glass tube so as to control the vapor pressure of mercury. SOLUTION: Inner diameter of a glass tube 2 is contracted so that a discharge tip 3a of a cathode discharge electrode 3 to be sealed in the glass tube 2 is projected from the end surface of the mercury of a mercury reservoir. The inner diameter of the tube 2 is contracted so that a discharge tip 4a of an anode discharge electrode 4 is arranged inside the mercury end surface 5a so as to form other mercury reservoir. Thickness of the tube 2 in the mercury reservoir, temperature of the cooling water 40 of the wall of the tube 2 and lamp input are constantly maintained, and evaporation area of the mercury end surface 5a is adjusted so as to control the mercury vapor pressure. With this structure, plasma positive column having the same diameter with the inner diameter of the tube 2 is formed, and the absorption of the ultraviolet rays in the short wavelength band in a gap space, in which mercury atoms between the electrodes 3, 4 exist, is prevented, and the generation of a stain near the tube wall is settled in one direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-high pressure mercury lamp, and more particularly to an improvement of an ultra-high pressure mercury lamp capable of controlling the vapor pressure of mercury.

[0002]

2. Description of the Related Art Conventionally, an ultra-high pressure mercury lamp has a mercury vapor pressure of 10 mm.
A mercury lamp that operates at a pressure higher than the atmospheric pressure (actually, 30 to 200 atm) is referred to as a general high-pressure mercury lamp.
Such a super-pressure mercury lamp has a distance between the electrodes of 0.2 mm to several tens.
At 0 mm, a high luminance of several thousand to several tens of thousands of cd / cm ² (stilb) can be obtained, and is widely used for photoetching or exposure.

FIG. 5 shows a straight tube type ultra-high pressure mercury lamp used for exposing a fluorescent screen applied to the inner surface of a face panel of a cathode ray tube. A certain amount of mercury is placed in a quartz discharge tube having a diameter of several mm. And a rare gas for starting.

A conventional ultra-high pressure mercury lamp and a conventional lamp housing for exposing a phosphor screen on a cathode ray tube panel will be described with reference to FIGS.

FIG. 5 is an external view of an ultra-high pressure mercury lamp, and FIG.
7 is a plan view of the lamp housing, and FIG. 8 is a side sectional view of the lamp housing.

The ultra-high pressure mercury lamp 1 will be described in detail with reference to FIGS. Reference numeral 2 denotes a glass tube made of quartz glass having an outer diameter of 4φ and an inner diameter of 1.2φ.
The cathode discharge electrode 3 and the anode discharge electrode 4 each formed of a tungsten rod having a diameter of about φ are sealed, and the tips of the tungsten rods are opposed to each other via an arc length of several mm to several tens mm within the inner diameter of the glass tube 2. . Mercury 5 and 5 are sealed in the inner diameter along the longitudinal direction of the cathode and anode discharge electrodes 3 and 4, and a discharge starting gas such as argon or xenon is sealed.

[0007] One end of the cathode discharge electrode 3 is a glass tube 2
And is electrically connected to a cathode terminal 6 formed of a metal round bar or the like, and is joined to the end face of the glass tube 2 via an adhesive or the like. This cathode terminal 6 is connected to the ground potential.

[0008] One end of the anode discharge electrode 4 is a glass tube 2
, The outer diameter of the glass tube 2 is inserted through the inner diameter of the holder 7 as shown in the sectional view of FIG.
It is fixed to the holder 7 via an epoxy-based adhesive 8.
A metal bush 9 is inserted into the other end of the holder 7 to form an anode terminal, which is connected to a commercial power supply or a high-frequency power supply.

The holder 7 is formed by sintering a ceramic tube having a stepped portion 7a of steatite or the like as shown in FIG.
As shown in FIG. 8, an air-tight bonding is performed with a silicon-based adhesive 10a or an adhesive 8 via an O-ring 10 as shown in FIG.

The anode discharge electrode 4 protruding from the end face of the glass tube 2, that is, the tip of a tungsten rod, for example, vertically sandwiches a lead wire 11 of a predetermined length of 0.1 mmt × 1.5 mmW nickel ribbon, The coil spring 12 is wound around the overlapped portion to perform soldering, and the anode discharge electrode 4 and the lead wire 11 are joined.

A silicon tube 13 is put on such a joint, the end of the glass tube 2 and the lead wire 11, and the inner diameter of the holder 7 is filled with an adhesive 8 and fixed. A bush (anode terminal) 9 fitted in the holder 7 is formed in a cylindrical shape, and the other end of the lead wire 11 is fixed to an end of the bush 9 with solder 14.

FIGS. 7 and 8 show the ultrahigh-pressure mercury lamp 1 constructed as described above inserted through the lamp housing 15, and R (red) and G applied to the inner surface of the face panel of the cathode ray tube.
It is disposed on the lower surface of an exposure table for exposing a fluorescent film such as (green) and B (blue).

Referring to FIGS. 7 and 8, a housing 15 includes a substantially square ultraviolet-ray emitting portion 15a made of metal and a cylindrical ultrahigh-pressure mercury lamp insertion portion 15b. A concentric counterbore hole 16 is formed at a substantially central position of the ultraviolet emitting portion 15a constituting a part of the housing 15, and a substantially rectangular window hole 17 is further formed. A convex lens 18 is hermetically attached to the counterbore 16 with a lens holder 20 via an O-ring 19.

An ultra-high pressure mercury lamp insertion portion 15b constituting a part of the housing 15 has a holder 7 through which the ultra-high pressure mercury lamp 1 described in detail in FIGS. 5 and 6 can be inserted in a direction perpendicular to the direction in which the counterbore 16 is formed. And a stepped insertion hole 21 having a diameter slightly larger than the outside diameter of the glass tube 2. At one end of the stepped insertion hole 21, a first counterbore 21 a for preventing insertion of the ultrahigh-pressure mercury lamp 1 is formed at a step 7 a formed at the outer peripheral portion of the holder 7, and at the other end, the cathode terminal 6 is formed. Is formed with a second counterbore 21b into which a cathode holder 22 for holding the hole can be fitted.

Further, in order to water-cool the glass tube 2 and the holder 7, two water passage holes 23 are formed from the side wall surface in front of the ultraviolet emitting portion 15a in FIG. Water for water cooling is injected from one of the water passage holes 23, and water is discharged from the other water passage hole 23. The ultrahigh-pressure mercury lamp 1 inserted into the stepped insertion hole 21 is cooled by water. Incidentally, reference numeral 24 denotes a ground terminal.

A male screw is formed at an outer diameter portion at the end of the ultrahigh-pressure mercury lamp insertion portion 15b, and a plug having a coupling ring 30 made of an insulating material formed with a female screw to be screwed with the male screw. 26 can be connected.

When the ultrahigh-pressure mercury lamp 1 is inserted into the stepped insertion hole 21 with the above-mentioned plug 26 removed, the stepped portion 7 is positioned at a position where the arc length of the glass tube 2 comes to the lower end of the window hole 17.
Stopped at a. The cathode terminal 6 side is the second counterbore 2
The O-ring 27 is screwed onto the bottomed cylindrical cathode holder 22 side without water leakage. A bottomed cylindrical spring receiver 28 is slidably disposed within the inner diameter of the cathode holder 22, and a coil spring 29 is disposed within the spring receiver 28 so that the end face of the cathode terminal 6 is fixed in one direction. Is pressed by the biasing force.

On the other hand, the plug 26 is a coupling, a ring 3
An outer shell 31 made of an insulator screwed to the outer shell 31 and an inner shell 32 inserted into the outer shell 31 and a carbon or the like, and a funnel is formed in the inner shell 32 so as to make line contact with the bush (anode terminal) 9. A high-voltage terminal 33 is press-fitted and connected to a secondary side of a step-up power transformer or the like via a cord 34 connected to the high-voltage terminal 33. Is supplied, and the ultra-high pressure mercury lamp 1 is turned on to irradiate the exposed surface with ultraviolet rays through the window hole 17.

[0019]

In the above-mentioned ultra-high pressure mercury lamp, when it is normally lit, it is lit using a commercial power supply having a frequency of 50 to 60 Hz. The time T ₁ in the half cycle of discharging in the plasma state is the sum of the rise time T ₀ and the fall time T ₂ , and the sum of the rise time and the fall time T ₂ Σ (T ₀ + T ₂ ) Is a loss time, which is approximately 25%.

On the other hand, the loss time in the sum of the rise time T ₀ ′ and the fall time T ₂ Σ (T ₀ ′ + T ₂ ′) when driven at a high frequency of 10 KHz to 30 KHz is approximately 10% to It is possible to improve the efficiency by 5%.

Further, when a boost voltage is supplied between the anode discharge electrode 4 and the cathode discharge electrode 3 from a commercial AC power supply or a high frequency power supply of 10 KHz to 30 KHz, the mercury pool of mercury 5 is as shown in the enlarged view of FIG. Discharge tips 3a and 4a of tungsten rods of anode and cathode discharge electrodes 3 and 4
a.

In such an ultra-high pressure mercury lamp 1, since the inner walls of the discharge tips 4a and 3a of the positive and negative discharge electrodes are AC-lit for AC lighting, there is a problem that both ends are stained and the ultraviolet radiation performance is deteriorated.

An object of the present invention is to provide an ultra-high pressure mercury lamp that solves the above-mentioned problems. The problem to be solved by the present invention is that the inner wall of the glass tube is not stained and the vapor pressure of mercury is controlled to shorten the mercury. It is an object of the present invention to obtain an ultra-high pressure mercury lamp capable of radiating a large amount of ultraviolet light in a wavelength band without attenuating the light to enhance an exposure effect at the time of exposing a phosphor screen.

[0024]

As shown in FIG. 1, an ultra-high pressure mercury lamp according to the present invention has cathode and anode discharge electrodes 3 and 4 which are sealed in a glass tube 2 so as to face each other. The anode mercury 5 disposed so as to cover the tip of the anode discharge electrode 4 and the tip of the cathode discharge electrode 3 protrude from the cathode mercury end face 5a, and a DC pulse is applied between the anode and the cathode discharge electrodes 4 and 3. In the ultra-high pressure mercury lamp supplied with the boosted voltage, the vapor pressure of mercury 5 in the glass tube 2 is controlled by changing the shape of the glass tube 2.

According to the ultrahigh pressure mercury lamp of the present invention, the electrons e emitted from the tip 3a of the cathode discharge electrode 3
Is absorbed by the mercury end face 5b covering the glass tube, these operations are continuously performed, and the discharge is turned into a plasma state, and the discharge is performed by a DC pulse having a predetermined duty. An ultra-high pressure mercury lamp capable of generating plasma and emitting a large amount of ultraviolet light on the short wavelength side can be obtained.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the ultra-high pressure mercury lamp of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic view of a discharge tube portion of an ultra-high pressure mercury lamp of the present invention, and FIG. 2 is a side sectional view showing one embodiment of the ultra-high pressure mercury lamp of the present invention.

In the ultrahigh pressure mercury lamp 1 according to the present invention,
Only the differences between the ultra-high pressure mercury lamp of the conventional configuration described in FIGS. 5 to 8 and its housing will be described with reference to FIGS.

FIGS. 1 and 2 are schematic views showing the same side cross section as the inside of the glass tube 2 of the extra-high pressure mercury lamp 1 described with reference to FIGS.
Has, for example, an outer diameter of 4 mmφ, an inner diameter of 1.2 mmφ, and a length of approximately 51 mm. The tungsten rod constituting the cathode discharge electrode 3 and the anode discharge electrode 4 has a high frequency lighting frequency of 1
In the case of lighting at 0 KHz or more, a diameter of 0.6 mmφ or more is required. The maximum diameter of a tungsten rod that can be used in the ultrahigh pressure mercury lamp 1 is up to 1.0 mmφ. The range is 0 mmφ.

The discharge tips 3a and 4a of the cathode and anode discharge electrodes 3 and 4 made of these tungsten rods are rounded off because the tungsten rods are cut and then heat-treated in a sealing step in the glass tube 2. For example, in the case of driving at a high frequency of 10 KHz, since the frequency is 200 times or more as compared with the frequency of the commercial power supply, the shape of the tip of the discharge tip 3 a of the cathode discharge electrode 3 stabilizes electron emission. It can be formed in a parabolic shape.

The cathode discharge electrode 3 and the anode discharge electrode 4 are sealed in the glass tube 2. The respective discharge tips 3a and 4a are disposed to face each other with a discharge gap of, for example, about 15 mm, and each tungsten rod projects outward from both ends of the glass tube 2 and is connected to the anode terminal 6 and the lead wire 11 described above. Is done.

In the discharge glass tube 2 of the present invention, the cathode discharge electrode 3 on the cathode side is the mercury end face 5 of the mercury pool of mercury 5.
a, the inner diameter of the glass tube 2 is reduced so that the discharge tip 3a protrudes from the discharge tip 4a of the anode discharge electrode 4.
“a” forms a mercury reservoir for mercury 5 by narrowing the inner diameter of the glass tube so as to be disposed inside the mercury end face 5b. still,
Reference numeral 40 denotes water supplied from the channel hole 23 to cool the tube wall.

Therefore, according to the present invention, the duty ratio of the DC pulse source 41 to the cathode discharge electrode 3 and the anode discharge electrode 4 is 10K.
By supplying a DC component of 30 Hz to 30 KHz, electrons e emitted from the discharge tip 3a of the cathode discharge electrode 3 are absorbed by the mercury end face 5b on the anode discharge electrode 4 side through a discharge gap filled with argon gas or the like. As a result, the ignition discharge is made into a plasma state.

In this case, the positive column formed into a plasma state is a glass tube 2 because a pulsed high frequency is applied.
The plasma becomes a wall-stabilized plasma which has spread almost completely on the inner diameter wall of the vessel.

In general, the wavelength of the spectral distribution of an ultra-high pressure mercury lamp used for exposing a fluorescent screen of a cathode ray tube or a black stripe is fixed, and the wavelength required for exposure is 5000 °.
In particular, it requires an ultraviolet band. 3650
と If there is much ultraviolet light in the following wavelength band, the energy required to print the phosphor film during exposure is so small that it does not affect other parts, so that it is possible to expose the phosphor screen with good resolution. It is required to be able to emit a large amount of wavelengths of 3650 ° or less.

In the present invention, the mercury end face 5b of the anode discharge electrode 4
In consideration of the evaporation area φ of the mercury 5, the thickness t of the glass tube of the mercury reservoir, the temperature of the cooling water 40, the lamp input, etc., the pressure at which the mercury 5 evaporates is controlled.

Now, assuming that the lamp input, the cooling temperature, and the glass thickness t are constant, the evaporation amount of mercury, that is, the vapor pressure can be changed by changing the aperture of the evaporation area φ of the mercury end face 5b.

As described above, by changing the evaporation area of the mercury end face 5b, the vapor pressure of mercury in the plasma generated in the gap space between the cathode and anode discharge electrodes 3 and 4 is controlled, and the high-frequency lamp driving by pulse waves is performed. Since an anode column of plasma having substantially the same diameter as the inner diameter of the glass tube 2 is formed, ultraviolet rays in a short wavelength band are not absorbed in the space where the evaporated mercury atoms exist in the gap space.
Ultraviolet rays of 50 ° or less can be emitted. Further, it is possible to increase the size (thickness) of the point light source of the ultraviolet light emitted from the window hole 17.

FIG. 2 shows a configuration based on the above principle.
Shows the discharge lamp tube part, mercury end face 5b
The aperture diameter glass tube 2, i.e. the evaporation area phi ₁ obtained by a 1.2 mm having the same diameter as the inner diameter, the value is the maximum value, 1.2 mm or less is the optimum value. Generally, the ultra-high pressure mercury lamp 1 is inserted into the housing 15 and arranged horizontally at the lower end of the exposure table. Therefore, the upper limit value of the holding range without the inclination of the mercury end face inside due to surface tension is φ ₁ =
1.2 mmφ.

The diameter of the tungsten rod of the cathode discharge electrode 3 is 0.6 mmφ to 1.0 mmφ, and the aperture diameter of the inner diameter forming the mercury pool of mercury 5 is 1.2 mmφ to 1.6 m.
mφ, which is also a range in which the mercury end face 5a is inclined and does not drip when placed at a horizontal position.

FIGS. 3 and 4 show the glass tube 2 of the present invention.
FIG. 3 is a side sectional view of an extra-high pressure mercury lamp showing another configuration in which the gap space and the anode discharge electrode 4 are changed.
Shows a case where the manner to increase the evaporation area phi ₂ of the cathode-side mercury end face 5b, to increase the plasma of the positive column by expanding the inner diameter d ₁ of the gap space.

FIG. 4 shows a case where the thickness t ₃ of the glass tube wall of the mercury reservoir of the anode discharge electrode 4 is reduced, and the diameter d _{2 of the} gap space is selected to be 1.2 mmφ or less.
Also in the cases shown in FIGS. 2 and 3, the thicknesses such as the tube wall thicknesses t ₁ and t ₂ are selected to be controlled to a predetermined thickness according to the temperature of the cooling water 40.

Since the ultrahigh-pressure mercury lamp of the present invention is driven by a direct current as described above, the discharge surface on the anode side can be used as the mercury end surface. Therefore, it is necessary to control the mercury evaporation area φ of the mercury end surface 5b on the anode side. Thus, the vapor pressure of mercury in the glass tube can be controlled, and the contamination near the electrode tube wall can be reduced in one direction.

In addition, the positive column of the plasma spreads so as to occupy substantially the entire gap space because of the high-frequency (pulse wave) lighting drive. In the remaining 40% of the mercury vapor, short-wavelength ultraviolet rays from the plasma are absorbed, but in this example, plasma is generated almost completely in the gap space. An ultrahigh-pressure mercury lamp that is not absorbed and is optimal as a light source for exposure can be obtained.

Further, considering the area as a point light source,
Since the size in the inner diameter direction (width direction) can be controlled, there is an effect that a point light source having a predetermined size as designed can be obtained.

[0045]

According to the ultrahigh-pressure mercury lamp of the present invention, by controlling the vapor pressure of mercury in the glass tube, it is possible to easily obtain an ultraviolet ray in a short wavelength band suitable for exposure without attenuating ultraviolet rays. Can be

[Brief description of the drawings]

FIG. 1 is a schematic view of a discharge tube part of an ultrahigh pressure mercury lamp of the present invention.

FIG. 2 is a side sectional view showing one embodiment of the ultra-high pressure mercury lamp of the present invention.

FIG. 3 is a side sectional view showing another embodiment of the extra-high pressure mercury lamp of the present invention.

FIG. 4 is a side sectional view showing still another embodiment of the extra-high pressure mercury lamp of the present invention.

FIG. 5 is an external view of a conventional ultra-high pressure mercury lamp.

FIG. 6 is a sectional view taken along the line AA ′ of FIG. 5;

FIG. 7 is a plan view of the lamp housing.

FIG. 8 is a side sectional view of a lamp housing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultra-high pressure mercury lamp 2 Glass tube 3 Cathode discharge electrode 4 Anode discharge electrode 5 Mercury 5a, 5b Mercury end face 40 DC pulse source

Claims (3)

[Claims] An anode mercury disposed so as to cover a tip of an anode discharge electrode of a cathode and an anode discharge electrode which are sealed in a glass tube and a tip of the cathode discharge electrode is disposed on a cathode side. In an ultra-high pressure mercury lamp protruding from a mercury end face and supplied with a boosted voltage of a DC pulse between the anode and the cathode discharge electrode, the shape of the glass tube is changed to change the mercury vapor pressure in the glass tube. An ultra-high pressure mercury lamp characterized by being controlled. 2. The ultra-high pressure mercury lamp according to claim 1, wherein the vapor pressure of mercury is controlled by controlling the evaporation area of the mercury on the anode side of the glass tube. 3. The ultra-high pressure mercury lamp according to claim 1, wherein the vapor pressure of mercury is controlled by controlling the glass thickness of the mercury reservoir on the anode side of the glass tube.