JP5364404B2 - Short arc type discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To substantially suppress illuminance fluctuation of a short arc type discharge lamp. <P>SOLUTION: The short arc type discharge lamp, with a cathode 20 and an anode 30 arranged in opposition inside an arc tube 12 with mercury and rare gas such as Ar sealed inside, is endowed with spectral distribution characteristics satisfying a formula: H<SB>334</SB>/H<SB>546</SB>&ge;0.35(M&ge;15). In the formula, a mercury volume is to be M where an intensity of an emission-line spectrum of 334 nm is represented as H<SB>334</SB>, and an intensity of that of 546 nm, as H<SB>546</SB>. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a short arc type discharge lamp used as a light source in an exposure apparatus or the like, and more particularly to a discharge lamp that suppresses fluctuation (illuminance fluctuation).

  In the short arc type discharge lamp, the anode and the cathode are held in the vicinity of the arc tube, and by applying a voltage, an arc discharge is generated between the electrodes, and light of a specific wavelength such as ultraviolet light is emitted. Since the short-arc discharge lamp has a short distance between the electrodes, it can be regarded as a point light source, and light with high radiance can be obtained.

  If the arc discharge becomes unstable while the lamp is lit, and the arc bright spot moves or the light emission length changes, no light is emitted as a point light source, resulting in illuminance reduction and illuminance fluctuation. In an exposure apparatus or the like, it is necessary to keep the illuminance uniform over the entire exposure surface, and illuminance fluctuations must be suppressed as much as possible.

  A discharge lamp with an improved electrode structure is known as a lamp that suppresses the illuminance fluctuation. For example, the illuminance fluctuation can be achieved by arranging the tip of the electrode on or on the plane including the maximum diameter portion of the arc tube. It suppresses (refer patent document 1). Alternatively, a part of the cathode body is formed in a taper shape, and a protrusion is provided on the taper portion to suppress the contraction and movement of the arc bright spot (see Patent Document 2).

Japanese Patent Laid-Open No. 10-269990 JP 2003-132837 A

  Even if the electrode structure of the lamp is improved, it is difficult to eliminate the illuminance fluctuation that is presumed to be caused by impurities in the arc tube. It is difficult to confirm the composition of impurities in the arc tube at the time of lamp manufacture, and it is impossible to find the correlation between the impurities in the arc tube and the illuminance fluctuation, and to realize a discharge lamp that suppresses the illuminance fluctuation as much as possible. It was difficult.

  The short arc type discharge lamp of the present invention is a discharge lamp capable of preventing illuminance fluctuations and irradiating light without fluctuation regardless of the electrode structure, and a discharge vessel in which at least mercury and a rare gas are enclosed, and the discharge vessel A pair of opposed electrodes. For example, a sealing tube is integrally formed on both sides of an arc tube formed of quartz glass or the like, and a mount component including an electrode support rod that supports an anode and a cathode is sealed in the sealing tube. Also, a rare gas such as Ar is sealed in the arc tube.

The short arc type discharge lamp of the present invention comprises a discharge vessel in which at least mercury and a rare gas are sealed, and a pair of electrodes arranged oppositely in the discharge vessel, and has a spectral distribution characteristic satisfying the following formula: Features.

H ₃₃₄ / H ₅₄₆ ≧ 0.35 (M ≧ 15) (1)

However, the amount of mercury enclosed in the discharge vessel is M (mg / cc), the intensity of the emission line spectrum at ₃₃₄ nm is H ₃₃₄ , and the intensity of the emission line spectrum at 546 nm is H ₅₄₆ .

  In the present invention, in a discharge lamp enclosing mercury, it has been found as a new finding that the spectral distribution characteristic (spectral characteristic) of emitted light has a correlation with illuminance fluctuation, and in particular, the spectrum in the band near 300 nm to 350 nm. Ascertaining that the distribution has an effect on fluctuations in illuminance, a discharge lamp having a spectral intensity in that band that is larger overall and average than that of a conventional discharge lamp is realized. That is, the spectrum of each wavelength in the vicinity of 300 nm to 350 nm has a relatively large intensity over the entire area as compared with the conventional discharge lamp.

One spectral conditional expression that quantitatively represents the spectral characteristics of the present invention is the expression (1). In the discharge lamp using mercury, bright line spectrum _{H 334} most light intensity is high in a band of wavelengths 300Nm～350nm. On the other hand, in other bands, for example, a wavelength region of 500 to 600 nm, the spectral intensity is almost the same as that of the conventional discharge lamp. In particular, there is almost no change in the light intensity of the emission line spectrum _H546 . Therefore, the spectral characteristics of the present invention can be expressed by the ratio between the bright line spectrum H ₃₃₄ and the bright line spectrum H ₅₄₆ .

  In the present invention, not a spectrum of 350 nm or more (g-line 436 nm, i-line 365 nm) used in an exposure apparatus or the like, but a spectral distribution characteristic around 300 to 350 nm, which has not been considered so far, is characterized. By having the spectral distribution characteristic characterized by the above equation (1), a short arc type discharge lamp in which the illuminance fluctuation is sufficiently suppressed is realized.

It is possible to suppress the illuminance fluctuation as long as the spectral ratio H ₃₃₄ / H ₅₄₆ satisfies the expression (1). If the spectral ratio H ₃₃₄ / H ₅₄₆ is approximately 0.35 or more (for example, 0.40), the illuminance fluctuation is suppressed. It is possible to suppress. In a discharge lamp used as a light source in a liquid crystal exposure apparatus, the amount of mercury M is often set in a range of 20 to 50 (mg / cc). In this case, a discharge lamp having a spectral characteristic in which the spectral ratio H ₃₃₄ / H ₅₄₆ is 0.39, and further when the mercury amount M is 30 (mg / cc) or more is 0.42 or more effectively suppresses fluctuations in illuminance. be able to.

On the other hand, the following formula is derived as another spectral condition formula that quantitatively represents the spectral characteristics of the present invention.

H ₃₅₀ / H ₅₀₀ ≧ 1.75 (M> 0) (2)

However, the spectral intensity at ₃₅₀ nm is H ₃₅₀ , and the spectral intensity at ₅₀₀ nm is H ₅₀₀ .

The spectrum H ₃₅₀ has a relatively small spectrum intensity in the wavelength range of 300 to ₃₅₀ nm. On the other hand, the spectrum H ₅₀₀ has a relatively small spectrum intensity in the wavelength range of 400 to 600 nm, and there is no significant change in light intensity from the conventional lamp. Accordingly, when the ratio between the spectrum H ₃₅₀ and the spectrum H ₅₀₀ , that is, the light intensity of the spectrum H _{350 based on} the spectrum H ₅₀₀ satisfies the equation (2), the spectrum intensity is generally large in the wavelength range of 300 to ₃₅₀ nm. Become.

It is possible to suppress the illuminance fluctuation as long as the spectral ratio H ₃₅₀ / H ₅₀₀ satisfies the expression (2). If the spectral ratio H ₃₅₀ / H ₅₀₀ is approximately 1.75 or more (for example, 2.0), the illuminance fluctuation can be suppressed. It is possible to suppress. In particular, the spectrum ratio H ₃₅₀ / H ₅₀₀ is 2.5 when the mercury amount M is 20 (mg / cc) or more, and the spectrum is 2.90 or more when the mercury amount M is 30 (mg / cc) or more. A discharge lamp having characteristics can effectively suppress fluctuations in illuminance.

Furthermore, the following formula is derived as another spectral condition formula that quantitatively represents the spectral characteristics of the present invention.

S ₁ ≧ 800 (M ≧ 15) (3)

However, the relative integrated intensity of light of 300 nm to 350 nm is S ₁ . The relative integrated intensity S ₁ indicates a value obtained by integrating the relative spectral intensity every 300 nm between 300 nm and 350 nm with reference to the emission line spectral intensity H ₃₆₅ of ₃₆₅ nm.

In the present invention, since the spectral intensity around 300nm~350nm is entirely large, the integrated values S ₁ becomes a large value that can not be obtained with conventional lamps. In particular, when the mercury amount M is 20 (mg / cc) or more, the integrated value S ₁ / H ₃₆₅ is 880, and further, the discharge lamp has a spectral characteristic that becomes 950 or more when the mercury amount M is 30 (mg / cc) or more. Can effectively suppress fluctuations in illuminance.

Furthermore, the following formula is derived as another spectral condition formula that quantitatively represents the spectral characteristics of the present invention.

S ₁ / H ₅₄₆ ≧ 8.00 (M ≧ 20) (4)

However, the relative integrated intensity of light of 300 nm to 350 nm is S ₁ , and the intensity of the emission line spectrum of 546 nm is H ₅₄₆ .

Since the light intensity of the bright line spectrum H ₅₄₆ is almost the same as that of the conventional lamp, the value S ₁ / H ₅₄₆ is a large value that cannot be obtained by the conventional lamp. In particular, a discharge lamp having a spectral characteristic in which S ₁ / H ₅₄₆ is 9.0 or more can effectively suppress illuminance fluctuation. Alternatively, if the mercury amount M is 30 mg / cc or more, it is possible to suppress the illuminance fluctuation at 7.0 or more.

The short arc type discharge lamp according to another aspect of the present invention is characterized in that the following expressions are satisfied when the intensity of the emission line spectra at wavelengths of 610 nm, 670 nm, and 365 nm are A ₆₁₀ , A ₆₇₀ , and A ₃₆₅ , respectively.

A ₆₁₀ / A ₃₆₅ ≦ 0.1 and A ₆₇₀ / A ₃₆₅ ≦ 0.2 (5)

  When a large amount of alkali metal such as lithium (Li) is contained as an impurity in the discharge vessel, the influence appears on the spectral distribution characteristics of 600 nm or more. Since lithium has a small ion radius, it escapes from the discharge vessel of the quartz glass having a network structure, so that the residual amount of lithium gradually decreases. As a result, it has been found that the spectral distribution characteristics of the lamp are not stable, causing illuminance fluctuations. In the present invention, since the condition of the formula (5) is satisfied, the illuminance fluctuation caused by alkali metal or the like does not occur.

Alternatively, in order to reduce the influence of the pressure change caused by the temperature rise in the discharge vessel or the like, when the wavelength is 691 nm as a reference, the short arc type discharge lamp has the intensity of emission line spectra of wavelengths 610 nm, 670 nm, and 691 nm as A _610. , A ₆₇₀ , A ₆₉₁ , it has a spectral distribution characteristic satisfying the following formula.

A ₆₁₀ / A ₆₉₁ ≦ 1 and A ₆₇₀ / A ₆₉₁ ≦ 2 (6)

  The manufacturing method of the short arc type discharge lamp according to the present invention inserts a mount part including a cleaned electrode into a cleaned bulb accommodated in the glove box, and heat-treats it in a vacuum furnace attached to the glove box. To do. Then, a rare gas and mercury are sealed in the valve while evacuating with an exhaust stand attached to the glove box. An annealing process is performed on the valve taken out from the glove box.

  As a manufacturing method that does not use a glove box other than the above manufacturing method, for example, a mounting component including an electrode is inserted into a valve, the mounting component is sealed by welding of the valve, and then annealed. Then, evacuation is performed for a predetermined time on the exhaust stand (heat treatment with a laser or a high frequency coil may be further performed for a predetermined time), and rare gas and mercury are enclosed. Thereafter, the chip is separated while being immersed in liquid nitrogen.

According to another aspect of the present invention, there is provided a method for manufacturing a short arc type discharge lamp, comprising: a discharge vessel in which at least mercury and a rare gas are enclosed; and a short arc type discharge lamp provided with a pair of electrodes disposed oppositely in the discharge vessel. The spectral distribution characteristics satisfying at least one of the following formulas, or the characteristics of the illuminance fluctuation rate and the lamp applied voltage fluctuation rate derived from such spectral distribution characteristics: It is determined whether the lamp is provided, and a final process is performed on the lamp having the spectral distribution characteristic or the illuminance fluctuation rate characteristic.

H ₃₃₄ / H ₅₄₆ ≧ 0.35 (M ≧ 15)
H ₃₅₀ / H ₅₀₀ ≧ 1.75 (M> 0)
S ₁ ≧ 800 (M ≧ 15)
S ₁ / H ₅₄₆ ≧ 8.00 (M ≧ 20) (7)

However, the intensity of the emission line spectrum at ₃₃₄ nm is H ₃₃₄ , the spectrum intensity at ₃₅₀ nm is H ₃₅₀ , the spectrum intensity at ₅₀₀ nm is H ₅₀₀ , the intensity of the emission line spectrum at 546 nm is H ₅₄₆ , and the relative integrated intensity of light at 300 nm to ₃₅₀ nm is S _Set to ₁ .

  According to the present invention, it is possible to know whether or not a lamp characteristic with constant illuminance is provided by determining spectral characteristics before the final process, and it is possible to deliver only a discharge lamp with constant illuminance. That is, even if the composition of impurities in the discharge vessel is not clarified, the lamp can be finally manufactured and shipped after confirming that the lamp has reduced illuminance fluctuation. The final process includes, for example, a process performed at the end after the completion of the lamp container manufacturing, gas filling, electrical component deployment, and the like such as dimension inspection. It can be applied only to quality inspection of lamp products.

  According to the present invention, illuminance fluctuations can be sufficiently suppressed in a short arc type discharge lamp.

It is a schematic plan view of a short arc type discharge lamp. It is the figure which showed the spectral distribution characteristic of the short arc type discharge lamp. It is the figure which showed the spectral distribution characteristic by the conventional short arc type discharge lamp. FIG. 5 is a diagram in which the spectral ratio (H ₃₃₄ / H ₅₄₆ ) between the intensity H ₃₃₄ of the emission line spectrum at ₃₃₄ nm and the intensity H ₅₄₆ of the emission line spectrum at 546 nm is plotted based on Table 4. FIG. 5 is a diagram in which the spectral ratio (H ₃₅₀ / H ₅₀₀ ) between the intensity H ₃₅₀ of the ₃₅₀ nm emission line spectrum and the intensity H ₅₀₀ of the ₅₀₀ nm emission line spectrum is plotted based on Table 4. It is the figure which plotted the integrated value of the relative spectral intensity of 300 nm-350 nm. It is a plot of the ratio of the spectrum relative integrated intensity _{S 1} and line spectrum intensity _{H 546} of 546nm in 300Nm～350nm. This lamp and conventional lamp integrated intensity ratio T _{1 /} T _2, it is a plot of the values. This lamp and the value of _H 313 / _{T 1} of the conventional lamp is a plot.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic plan view of a short arc type discharge lamp 10.

  The short arc type discharge lamp 10 includes an arc tube 12 made of transparent quartz glass, and a cathode 20 and an anode 30 are disposed in the arc tube 12 so as to face each other with a predetermined interval. On both sides of the arc tube 12, quartz glass sealing tubes 13 </ b> A and 13 </ b> B are connected to the arc tube 12 and are integrally formed.

  Inside the sealing tubes 13A and 13B, conductive electrode support rods 17A and 17B for supporting the cathode 20 and the anode 30 are disposed, and the conductive lead rods 15A and 15B are interposed through the metal foils 16A and 16B, respectively. Connected. Both ends of the sealing tubes 13A and 13B are closed by the caps 19A and 19B. Further, the sealing tubes 13A and 13B are welded to a glass tube 21 and a glass rod (not shown) provided in the inside, and thereby the discharge space in the arc tube 12 is sealed.

  The arc tube 12 is filled with rare gas such as mercury and argon gas. The amount of mercury is enclosed in the range of about 5 to 50 (mg / cc). For example, when the short arc type discharge lamp 10 is used as the illumination lamp of the liquid crystal exposure apparatus, at least 20 (mg / cc) or more of mercury is enclosed in the arc tube 12.

  The lead bars 15A and 15B are connected to an external power source (not shown), and power is supplied to the cathode 20 and the anode 30 via the lead bars 15A and 15B. When a voltage is applied between the cathode 20 and the anode 30, an arc discharge is generated between the electrodes, and light is radiated out of the arc tube 12 as illumination light.

  FIG. 2 is a diagram showing the spectral distribution characteristics of the short arc type discharge lamp 10. Here, the amount of mercury to be enclosed is 30 mg / cc, and the spectral distribution is shown when the lamp is lit with power of 10 kW. For the measurement of the spectrum, an illuminometer having a slit width of approximately 0.1 mm or less (here, 0.5 mm) and a wavelength width of each light receiving element of around 1 nm (here, 1.2 nm) is used. In addition, relative intensity (illuminance) with the 365 nm spectrum as a reference (= 100) is shown.

  On the other hand, FIG. 3 is a diagram showing spectral distribution characteristics of a conventional short arc type discharge lamp. The conventional short arc type discharge lamp has the same light emission conditions such as mercury content and pressure inside the arc tube.

  The spectral distributions shown in FIGS. 2 and 3 include several mercury emission line spectra, and different emission line spectra are used depending on the usage environment of the lamp. For example, emission line spectra of 365 nm and 436 nm are used as illumination light for an exposure apparatus or the like as i-line and g-line, respectively.

The spectral distribution SA shown in FIG. 2 is characterized by a relatively large spectral intensity in the short wavelength (ultraviolet) region. In particular, the spectrum intensity is generally large in the band near 300 nm to 350 nm, and it appears remarkably in the wavelength region B between the ₃₁₃ nm emission line spectrum H ₃₁₃ and the 365 nm emission line spectrum.

  The spectral distribution SB shown in FIG. 3 is a spectral intensity in the vicinity of 300 nm to 350 nm, but the spectral intensity is generally smaller than that in FIG. In particular, the spectral intensity in the wavelength region B is greatly different from the spectral intensity in FIG.

  The relative magnitude of the spectral intensity in the vicinity of 300 nm to 350 nm is independent of the adjustment of the amount of enclosed mercury and the increase in power, and no impurities that affect the light in the vicinity of 300 nm to 350 nm remain in the arc tube 12. This is due to this. In the present embodiment, a lamp with a sufficiently suppressed illuminance fluctuation is realized by stabilizing the spectral intensity in the vicinity of 300 nm to 350 nm, which is generally not directly involved as illumination light. Even if the amount of rare gas and mercury to be enclosed is changed, the same spectral intensity as in FIG. 2 is generated in the vicinity of 300 nm to 350 nm, and the average spectral intensity in the band near 300 nm to 350 nm is about 20 or more.

  That is, in the conventional short arc type discharge lamp, the spectral intensity in the vicinity of 300 nm to 350 nm is lowered and unstable due to the influence of impurities and the like, and illuminance fluctuation is likely to occur. However, in the case of the short arc type discharge lamp according to the present embodiment, the spectral intensity is large and stable in the vicinity of 300 nm to 350 nm, so that the illuminance fluctuation does not occur.

The spectral distribution SA of FIG. 2 is characterized in that the intensity of the ₆₁₀ nm emission line spectrum H ₆₁₀ and the 670 nm emission line spectrum H ₆₇₀ is small. In the wavelength region of 600 nm or more, there is an emission line spectrum of alkali metal, and in particular, since an atomic spectrum line of lithium (Li) and an atomic resonance spectrum are 610 nm and 670 nm, emission line spectra H ₆₁₀ and H of ₆₁₀ nm and 670 nm ₆₇₀ is an index representing the residual amount of lithium in the arc tube 12.

In the spectral distribution characteristics of FIG. 3, the spectral intensities of the bright line spectra H ₆₁₀ and H ₆₇₀ are larger than the spectral intensities of FIG. This represents a large residual amount of alkali metal such as lithium. For this reason, lithium having a relatively small ion diameter in the alkali metal jumps out of the arc tube with the passage of time, resulting in fluctuations in illuminance.

  Here, a manufacturing method of the short arc type discharge lamp 10 having the spectral distribution characteristic as shown in FIG. 2 will be described below.

  First, the arc tube portion of the glass tube is thermoformed to form a bulb in which sealing tubes are continuously provided on both sides of the elliptical arc tube. Then, in order to remove impurities adhering by thermoforming, valve cleaning is performed by performing valve heat treatment at a high temperature and in a vacuum state. Note that a tip tube for enclosing mercury and a rare gas in a subsequent process is formed at the time of bulb molding.

  On the other hand, in order to remove impurities adhering to the electrode, electrode cleaning is performed in which electrode heat treatment is performed at a high temperature and in a vacuum state. Then, a mounting part including a metal part such as an electrode, an electrode support rod, and a metal foil and a glass tube for holding the metal part is assembled.

  Next, a glove box with a vacuum furnace and an exhaust stand is prepared, and a valve is accommodated in the glove box in a rare gas atmosphere. Then, the mount component is inserted into the glove box and sealed in the sealing tube portion of the valve. After the mounting parts are enclosed, the valves are heat-treated in the attached vacuum furnace. Then, the inside of the valve is evacuated in the attached exhaust stand, and mercury and a rare gas are enclosed.

  After sealing mercury and rare gas, the chip tube is cut off, the mount component is welded to the sealing tube, and the mount component is sealed in the sealing tube. Then, annealing is performed to remove residual stress in a vacuum heat treatment apparatus communicating with the glove box.

  After mounting electrical components such as connection cords on the mount parts, the illuminance fluctuation rate of the light emitted from the lamp is measured with an illuminometer. Specifically, the illuminance is measured at regular time intervals, and the illuminance fluctuation rate for a predetermined period is calculated. When it is confirmed that the illuminance fluctuation rate satisfies the requirements, that is, the spectral distribution characteristic as shown in FIG. 2 appears, process processing as a short arc type discharge lamp is finally performed (quality inspection etc.), and the short arc Type discharge lamp is completed.

  Next, the spectral characteristics shown in FIG. 2 will be described quantitatively. From the spectral intensity when the amount of mercury to be enclosed (mg / cc) is changed, the relative integrated intensity of the spectrum, and the like, it is possible to quantitatively represent the spectral distribution characteristics that bring about a constant illuminance.

Tables 1 and 2 show the spectral intensities of the short arc type discharge lamp of the present embodiment (hereinafter referred to as the main lamp) and the conventional short arc type discharge lamp (hereinafter referred to as the conventional lamp). Here, the value of the relative intensity with the intensity H ₃₆₅ of the emission line spectrum as 100 is shown.

  Next, Tables 3 and 4 divide the wavelength region of 300 nm to 500 nm into four 50 nm, and show the relative spectral integrated intensity of each area. The relative integrated intensity represents a value obtained by integrating the relative spectral intensity every 300 nm between 300 nm and 350 nm with reference to the emission line spectral intensity of 365 nm. In the calculation of the ratio for comparing the relative integrated intensities, the spectral relative integrated intensities from 350 nm to 400 nm are used as the reference (= 1).

Tables 5 and 6 show the ratio (S ₁ / H ₅₄₆ ) of the relative integrated intensity (S ₁ ) of light at 300 nm to 350 nm and the intensity of the emission line spectrum at 546 nm (H ₃₃₄ ) and the intensity (H ₃₃₄ ) of the emission line spectrum at ₃₃₄ nm. Spectral ratio (H ₃₃₄ / H ₅₄₆ ) of ₅₄₆ nm emission line intensity (H ₅₄₆ ), spectral ratio of 350 nm spectral intensity (H ₃₅₀ ) to 500 nm spectral intensity (H ₅₀₀ ) (H ₃₅₀ / H ₅₀₀ ), 300 nm The relative integrated intensity (S ₁ ) of light at ˜350 nm is shown. Each value is obtained based on the spectral intensity and the relative integrated intensity in Tables 1 to 4.

  It is possible to quantitatively represent that the spectral characteristics of the discharge lamp of the present embodiment, that is, the spectral intensity in the vicinity of 300 nm to 350 nm is large by the obtained spectral ratio, integrated value, and the like, compared with the conventional discharge lamp. However, the difference in the spectral characteristics will be described below.

FIG. 4 is a graph in which the spectral ratio (H ₃₃₄ / H ₅₄₆ ) between the intensity H ₃₃₄ of the emission line spectrum at ₃₃₄ nm and the intensity H ₅₄₆ of the emission line spectrum at 546 nm is plotted based on Tables 5 and 6.

The spectrum intensity H ₃₃₄ is the intensity of the emission line spectrum at ₃₃₄ nm included in the band near 300 nm to 350 nm (see FIG. 2). If the intensity H _{334 of the} emission line spectrum is large, the surrounding spectrum intensity is also increased as a whole. Tend to be larger.

On the other hand, the intensity H ₅₄₆ of the emission line spectrum at 546 nm outside the band of 300 nm to 350 nm does not cause a large difference between the conventional lamp and the discharge lamp of the present embodiment. Therefore, the spectral ratio H ₃₃₄ / H ₅₄₆ is a parameter indicating the degree of the overall spectral intensity around 300 nm to 350 nm including the ₃₃₄ nm emission line spectrum.

As shown in FIG. 4, the spectral ratio H ₃₃₄ / H ₅₄₆ of the conventional lamp does not exceed 0.35 even if the mercury amount M is changed. On the other hand, the spectral ratio H ₃₃₄ / H ₅₄₆ of this embodiment exceeds 0.35 when the mercury amount is 16 mg / cc or more. Therefore, when the spectral ratio H ₃₃₄ / H ₅₄₆ satisfies the following expression, it can be considered that a discharge lamp having a spectral distribution characteristic as shown in FIG. 2 is obtained.

H ₃₃₄ / H ₅₄₆ ≧ 0.35 (M ≧ 15) (8)

However, the amount of mercury enclosed in the discharge vessel is M (mg / cc). If the spectral ratio H ₃₃₄ / H ₅₄₆ is 0.35 or more (for example, 0.37, 0.38), it can be considered that the spectral distribution characteristics shown in FIG. 2 are provided. In particular, when the mercury amount M is 30 mg / cc or more, the spectral ratio H ₃₃₄ / H ₅₄₆ becomes 0.42 or more. When H ₃₃₄ / H ₅₄₆ is 0.39 or more, the spectral distribution characteristic shown in FIG. 2 is obtained.

FIG. 5 is a graph in which the spectral ratio (H ₃₅₀ / H ₅₀₀ ) between the intensity H ₃₅₀ of the ₃₅₀ nm emission line spectrum and the intensity H ₅₀₀ of the ₅₀₀ nm emission line spectrum is plotted based on Tables 5 and 6.

Light having wavelengths of 350 nm and 500 nm is not an emission line spectrum, and its spectral intensities H ₃₅₀ and H ₅₀₀ are relatively close to the lowest spectral value (see FIG. 2). When the spectral intensity H ₃₅₀ increases, the spectral intensity around the wavelength of 300 nm to ₃₅₀ nm tends to increase overall. On the other hand, the spectral intensity H ₅₀₀ is not significantly different between the conventional lamp and the discharge lamp of the present embodiment.

Therefore, when the ratio of spectrum H ₃₅₀ to spectrum H ₅₀₀ (H ₃₅₀ / H ₅₀₀ ) satisfies the following formula, it can be considered that a discharge lamp having the spectrum distribution characteristics as shown in FIG. 2 is obtained.

H ₃₅₀ / H ₅₀₀ ≧ 1.75 (M> 0) (9)

If the spectral ratio H ₃₅₀ / H ₅₀₀ is 1.75 or more (for example, 1.80, 1.90), it can be considered that the spectral distribution characteristics shown in FIG. 2 are provided. In particular, when the mercury amount M is 20 mg / cc or more, the spectrum ratio H ₃₅₀ / H ₅₀₀ is 2.50, and when the mercury amount M is 30 mg / cc or more, the spectrum ratio H ₃₅₀ / H ₅₀₀ is 2.90 or more. 2 is provided.

Figure 6 is a plot of relative intensity integrated values _{S 1} of 300Nm～350nm.

As shown in FIG. 6, in the conventional lamp, the relative integrated intensity S ₁ does not exceed 800. On the other hand, when the mercury amount M is 15 mg / cc or more, the relative integrated intensity of the lamp is 800 or more. Therefore, when the following expression is satisfied, it can be considered that a discharge lamp having a spectral distribution characteristic as shown in FIG. 2 is obtained.

S ₁ ≧ 800 (M ≧ 15) (10)

If the relative integrated intensity _{S 1} is 800 or more (eg 830,860), regarded as those equipped with spectral distribution characteristic shown in FIG. In particular, when the mercury amount M is 20 mg / cc or more, the relative cumulative intensity S ₁ is 950 or more.

7, the ratio of the spectrum relative integrated intensity _{S 1} and line spectrum intensity _{H 546} of 546nm in 300Nm～350nm (hereinafter, referred to as the spectral ratio integrated intensity) is a plot of.

As shown in FIG. 7, when the mercury amount M is 20 mg / cc or more, in the conventional lamp, the spectral ratio integrated intensity S ₁ / H ₅₄₆ does not exceed 8.00. On the other hand, in this lamp, the spectral ratio integrated intensity S ₁ / H ₅₄₆ is 8.00 or more.

Therefore, when the following expression is satisfied, it can be considered that a discharge lamp having a spectral distribution characteristic as shown in FIG. 2 can be obtained.

S ₁ / H ₅₄₆ ≧ 8.00 (M ≧ 20) (11)

If the spectrum ratio integrated intensity S ₁ / H ₅₄₆ is 8.00 or more (for example, 8.30, 8.50), it can be considered that the spectrum distribution characteristic shown in FIG. 2 is provided. In particular, in the conventional lamp, the spectral ratio integrated intensity S ₁ / H ₅₄₆ does not exceed 9.00 regardless of the mercury amount M, and if it is 9.00 or more, it can be considered that the spectral distribution characteristics shown in FIG. Further, when the mercury amount M is 30 mg / cc, the spectral distribution characteristic shown in FIG. 2 is obtained at 7.00 or more.

  As described above, when any one of the equations (8) to (11) is satisfied, the spectrum distribution characteristic has a characteristic that the spectrum intensity is generally large in the vicinity of 300 nm to 350 nm as shown in FIG.

  Other than the equations (8) to (11), the spectral distribution characteristics of the present embodiment can be expressed quantitatively, and are expressed by a curve equation as shown below. However, the amount of mercury M is required to be 30 mg / cc or less.

_T 1 the relative integrated intensity of the light 300Nm～350nm, when the relative integrated intensity of the light 350nm~400nm was _{T 2,} the ratio of the relative integrated intensity _{T 1} relative integrated intensities _{T 2} (hereinafter, integrated intensity ratio _{of) T} 1 / T _2, and line spectrum intensity _{H 313} and the ratio of the relative integrated intensity _{T 1} (hereinafter, referred to as bright line intensity _{ratio) H} 313 / _{T 1} is determined. It is shown in Table 7 below.

As is clear from Table 7, the integrated intensity ratio T ₁ / T ₂ of the short arc discharge lamp of this embodiment is greater than the integrated intensity ratio of the conventional lamp at any mercury amount. On the other hand, the value of the bright line intensity ratio H ₃₁₃ / T ₁ of the short arc type discharge lamp of the embodiment is smaller than the bright line intensity ratio of the conventional lamp. Therefore, the conditions of the integrated intensity ratio T ₁ / T ₂ and the bright line intensity ratio H ₃₁₃ / T ₁ representing the characteristics of the spectral distribution characteristics of FIG. 2 are defined as follows.

FIG. 8 is a graph in which the integrated intensity ratio T ₁ / T ₂ of the present lamp and the conventional lamp is plotted based on Table 7. FIG. 9 is a diagram in which the value of the bright line intensity ratio H ₃₁₃ / T ₁ of the present lamp and the conventional lamp is plotted based on Table 7.

As is apparent from FIG. 8, the integrated intensity ratio of this lamp is larger than T ₁ / T ₂ compared to the conventional lamp. This means that the relative spectral intensity in the wavelength region near 300 nm to 350 nm is different from that of the conventional lamp.

Therefore, if the value of the integrated intensity ratio T ₁ / T ₂ is equal to or greater than the condition value according to each mercury amount, it is considered that the same spectral distribution characteristics as those in FIG. 2 are provided. Since the condition value is expressed by a function having the mercury amount M as a variable, a curve G1 is defined based on plots K1 to K3 and K01 to K03 of the main lamp and the conventional lamp. And the following conditional expression is calculated | required by making the curve G1 into a boundary line.

T ₁ / T ₂ ≧ 1-6 (M-5) ² × 10 ⁻⁴ (12)

However, the right side of the expression (12) is expressed by a quadratic function of the mercury amount M with the curve G1 as an approximate expression. It is assumed that the amount of mercury M is used in the range of about 5 to 30 (mg / cc).

On the other hand, when the curve G2 is defined based on the plots L1 to L3 and L01 to L03 shown in FIG. 9, the following conditional expression is obtained using the curve G2 as a boundary line.

H ₃₁₃ / T ₁ ≦ 170 (M + 30) ⁻² −1 × 10 ⁻² ... (13)

However, the right side of the equation (13) represents an approximate expression of the curve G2.

  This lamp satisfying the expressions (12) and (13) means that it has the characteristics of the spectral distribution characteristics shown in FIG. 2, and the characteristics of the lamp are quantitatively expressed by the expressions (12) and (13). can do.

  As described above, it has been explained that the characteristics of the spectral distribution characteristics as shown in FIG. 2 can be quantitatively expressed by the equations (8) to (13). Conversely, a certain discharge lamp has (8) to (13). 2), it is proved that the discharge lamp achieves the spectral distribution characteristic shown in FIG. Therefore, by determining whether or not the spectral distribution characteristics satisfy the expressions (8) to (13) before the final step of the manufacturing process, only lamps having no illuminance fluctuation can be shipped. Even if the rare gas to be sealed is changed to Xe instead of Ar, the equations (8) to (13) are satisfied.

Incidentally, in the spectral distribution characteristic shown in FIG. 2, the spectral intensities of the bright line spectra H ₆₁₀ and H ₆₇₀ are smaller than those of the conventional lamp in the wavelength region of 600 nm or more as described above (see FIGS. 2 and 3). The intensities of the emission line spectra H ₆₁₀ and H _{670 at 610} and ₆₇₀ nm and the emission line spectrum H ₃₆₅ of mercury at 365 nm are shown in Table 8 below. However, the intensity of the bright line spectrum H ₃₆₅ is set as a reference (= 1).

The bright line spectra H ₆₁₀ and H ₆₇₀ are considered to be the bright line spectrum of Li which is an impurity residue. Therefore, when the intensity of the emission line spectra at wavelengths of 610 nm, 670 nm, and 365 nm is A ₆₁₀ , A ₆₇₀ , and A ₃₆₅ , this lamp satisfies the following conditional expression.

A ₆₁₀ / A ₃₆₅ ≦ 0.1 and A ₆₇₀ / A ₃₆₅ ≦ 0.2
.... (14)

On the other hand, Table 9 below shows the intensity of the emission line spectra H ₆₁₀ and H ₆₇₀ at ₆₁₀ and ₆₇₀ nm, and the intensity of the emission line spectrum H ₆₉₁ of mercury at ₆₉₁ nm is used as the reference (= 1).

When the intensity of the emission line spectra at wavelengths of 610 nm, 670 nm, and 691 nm are A ₆₁₀ , A ₆₇₀ , and A ₆₉₁ , this lamp satisfies the following conditional expression.

A ₆₁₀ / A ₆₉₁ ≦ 1 and A ₆₇₀ / A ₆₉₁ ≦ 2 (15)

By using the bright line spectrum H ₆₉₁ as a reference, the value of the spectrum intensity is eliminated as much as possible from the influence of the pressure in the discharge lamp.

  Satisfying the above expressions (14) and (15) means that impurities such as lithium do not remain, and indicates that the lamp can suppress fluctuations in illuminance by the spectral distribution characteristics shown in FIG.

  The illumination fluctuation rate of this lamp and the conventional lamp was measured and compared. As an example of this lamp, a lamp having an arc tube having an outer diameter of 121 mm and a volume of 855 cc, a tungsten anode containing potassium of about 0.002% by weight, and tungsten containing thorium oxide of about 2% by weight A short arc type discharge lamp in which manufactured cathodes were arranged to face each other at an interval of 12 mm was produced. The manufacturing method was performed by the above-described manufacturing method, in which 30 mg / cc of mercury was sealed, and Ar gas was sealed so as to be about 190 kPa at room temperature.

  On the other hand, the conventional lamp manufacturing method is not the above-described manufacturing method, but a conventional manufacturing method. As an example, first, after the mount component is inserted into the valve, a sealing process is performed, and distortion due to residual stress is removed by an annealing process. At this time, a high-purity gas such as argon is sealed in the arc tube at a pressure lower than atmospheric pressure to prevent bulb deformation.

  After annealing, attach a valve to the exhaust stand. In the exhaust stand, an exhaust device and a gas cylinder are connected to a tip tube formed integrally with the valve, and each communicates with the valve through the tip tube. On the other hand, mercury is sealed in a tank formed integrally with the tip tube and stored so as not to evaporate. Then, evacuation and rare gas filling are performed on the arc tube and the inside of the tank, and the gas in the bulb is replaced with high purity gas.

  Then, the arc tube and the tank are evacuated to the bulb, and a rare gas is sealed inside the arc tube. After the tip tube is cut off at a portion close to the exhaust device, the mercury in the tank is moved into the arc tube, and the tip tube is cut off in the vicinity of the bulb while the rare gas inside is liquefied. The amount of mercury enclosed and the arc pressure in the arc tube of Ar gas are set to the same values as in this lamp.

The main lamp and the conventional lamp were turned on at a constant voltage of 10 kW, and the illuminance fluctuation rate was measured with an illuminometer having a strong sensitivity region around 350 nm. As the illuminometer, a multi-side optical system MC-3000-28C (manufactured by Otsuka Electronics Co., Ltd.) was used. The spectroscope of this illuminometer is a blazed holographic type, F = 3, f = 135 mm, measurement wavelength range 220-800 nm, self-operating detection element 512ch, slit width 0.05 mm, per light receiving element The wavelength width is 1.2 nm. Here, detection is performed at a sampling interval of 1 msec, an average is calculated every 20 data, and the average is detected over 1 minute. The maximum value and the minimum value of the average data in one minute and the average value thereof were calculated and obtained by the following formula. However, X is the maximum value, Y is the minimum value, W is the average value, and E is the illuminance fluctuation rate.

E = ((X−Y) / W) × 100 (16)

Table 10 below shows the illuminance fluctuation rate (%) of this lamp and the conventional lamp.

  As shown in Table 10, the illuminance fluctuation rate of this lamp is extremely small, far below 1% required by the exposure apparatus or the like. Even if this lamp and the conventional lamp are manufactured in the same manner with the mercury filling amount set to 5 mg / cc and 15 mg / cc, the same result as the illuminance fluctuation rate shown in Table 10 is obtained, and 0.5% or less is obtained. Satisfied. Moreover, the same result can be obtained even if the illuminance fluctuation rate is defined by a method other than the calculation method described above.

  Instead of the illuminance variation rate, the variation rate of the voltage applied to the lamp may be measured, and the lamp voltage variation rate caused by the illuminance variation due to fluctuation may be measured. Or you may comprise so that it may be confirmed whether it is a lamp | ramp which has the said spectral distribution characteristic using the instrument which measures spectral distribution.

The amount of mercury was changed from that of the lamp of Example 1, and the voltage fluctuation rate was compared with that of the conventional lamp. Conditions other than the amount of mercury are substantially the same as in Example 1. The voltage fluctuation rate is detected at a sampling interval of 1 msec, an average is calculated every 20 data, and the average is detected over 1 minute. The maximum value and the minimum value of the average data in one minute and the average value thereof were calculated and obtained by the following formula. However, X1 is the maximum value, Y1 is the minimum value, W1 is the average value, and V1 indicates the voltage fluctuation rate.

V1 = ((X1-Y1) / W1) × 100 (17)

The following table shows the voltage fluctuation rate (%) of this lamp and the conventional lamp.

  As shown in Table 11, even when the mercury amount M is turned on at 5 mg / cc and 40 mg / cc, it is clear that the voltage fluctuation rate, that is, the illuminance fluctuation rate is smaller than that of the conventional lamp.

10 Short Arc Type Discharge Lamp 12 Arc Tube 20 Cathode 30 Anode SA Spectral Distribution

Claims (11)

A discharge vessel mercury and a rare gas is sealed,
A pair of electrodes disposed opposite to each other in the discharge vessel,
The residual amount of impurities in the discharge vessel is
The amount of mercury enclosed in the discharge vessel is M (mg / cc),
The intensity of the emission line spectrum at ₃₃₄ nm is H ₃₃₄ ,
When the intensity of the emission line spectrum at 546 nm is H ₅₄₆ , the following formula

H ₃₃₄ / H ₅₄₆ ≧ 0.35 (M ≧ 15)

A short arc type discharge lamp characterized by being a residual amount that realizes radiation of light having a spectral distribution characteristic satisfying A discharge vessel mercury and a rare gas is sealed,
A pair of electrodes disposed opposite to each other in the discharge vessel,
The residual amount of impurities in the discharge vessel is
The amount of mercury enclosed in the discharge vessel is M (mg / cc),
The intensity of the ₃₅₀ nm emission line spectrum is H ₃₅₀ ,
When the intensity of the emission line spectrum at 500 nm is H ₅₀₀ , the following formula

H ₃₅₀ / H ₅₀₀ ≧ 1.75 (M> 0)

The meet and, a short arc type discharge lamp, which is a residual amount to achieve the emission of light having a spectral distribution characteristic line spectrum of mercury is present. A discharge vessel mercury and a rare gas is sealed,
A pair of electrodes disposed opposite to each other in the discharge vessel,
The residual amount of impurities in the discharge vessel is
The amount of mercury enclosed in the discharge vessel is M (mg / cc),
When the relative integrated intensity of light of 300 nm to 350 nm with reference to the intensity H ₃₆₅ of the emission line spectrum at 365 nm is S ₁ ,

S ₁ ≧ 800 (M ≧ 15)

A short arc type discharge lamp characterized by being a residual amount that realizes radiation of light having a spectral distribution characteristic satisfying A discharge vessel mercury and a rare gas is sealed,
A pair of electrodes disposed opposite to each other in the discharge vessel,
The residual amount of impurities in the discharge vessel is
The amount of mercury enclosed in the discharge vessel is M (mg / cc),
The relative integrated intensity of light of 300 nm to 350 nm with reference to the intensity H ₃₆₅ of the emission line spectrum of 365 nm as S ₁ ,
When the intensity of the emission line spectrum at 546 nm is H ₅₄₆ , the following formula

S ₁ / H ₅₄₆ ≧ 8.00 (M ≧ 20)

A short arc type discharge lamp characterized by being a residual amount that realizes radiation of light having a spectral distribution characteristic satisfying 2. The short arc discharge lamp according to claim 1, wherein the residual amount of impurities in the discharge vessel is a residual amount that realizes radiation of light having a spectral distribution characteristic that satisfies the following expression.

H ₃₃₄ / H ₅₄₆ ≧ 0.39 (M ≧ 20)
3. The short arc discharge lamp according to claim 2, wherein the residual amount of impurities in the discharge vessel is a residual amount that realizes radiation of light having a spectral distribution characteristic that satisfies the following formula.

H ₃₅₀ / H ₅₀₀ ≧ 2.50 (M ≧ 20) 4. The short arc discharge lamp according to claim 3, wherein the residual amount of impurities in the discharge vessel is a residual amount that realizes light emission having a spectral distribution characteristic that satisfies the following formula.

S ₁ ≧ 880 (M ≧ 20) 5. The short arc discharge lamp according to claim 4, wherein the residual amount of impurities in the discharge vessel is a residual amount that realizes radiation of light having a spectral distribution characteristic that satisfies the following expression.

S ₁ / H ₅₄₆ ≧ 9.00 (M> 0) When the residual amount of impurities in the discharge vessel is A ₆₁₀ , A ₆₇₀ , and A ₃₆₅ , respectively, with the intensity of emission line spectra at wavelengths of 610 nm, 670 nm, and 365 nm, the following equations

A ₆₁₀ / A ₃₆₅ ≦ 0.1 and A ₆₇₀ / A ₃₆₅ ≦ 0.2

The short arc type discharge lamp according to claim 1, wherein the short arc type discharge lamp is a residual amount that realizes radiation of light having a spectral distribution characteristic satisfying the above. When the residual amount of impurities in the discharge vessel is A ₆₁₀ , A ₆₇₀ , and A ₆₉₀ , respectively, the intensity of the emission line spectra of mercury at wavelengths of 610 nm, 670 nm, and 691 nm is

A ₆₁₀ / A ₆₉₁ ≦ 1 and A ₆₇₀ / A ₆₉₁ ≦ 2

The short arc type discharge lamp according to claim 1, wherein the short arc type discharge lamp is a residual amount that realizes radiation of light having a spectral distribution characteristic satisfying the above. A discharge vessel mercury and a rare gas is sealed, there is provided an inspection method of the short arc type discharge lamp having a pair of electrodes disposed opposite to the discharge vessel,
The amount of mercury enclosed in the discharge vessel is M (mg / cc),
The intensity of the emission line spectrum at ₃₃₄ nm is H ₃₃₄ ,
The intensity of the ₃₅₀ nm emission line spectrum is H ₃₅₀ ,
The intensity of the emission line spectrum at 500 nm is H ₅₀₀ ,
The intensity of the emission line spectrum at 546 nm is H ₅₄₆ ,
When the relative integrated intensity of light of 300 nm to 350 nm with reference to the intensity H ₃₆₅ of the ₃₆₅ nm emission line spectrum is S ₁ ,

H ₃₃₄ / H ₅₄₆ ≧ 0.35 (M ≧ 15)
H ₃₅₀ / H ₅₀₀ ≧ 1.75 (M> 0)
S ₁ ≧ 800 (M ≧ 15)
S ₁ / H ₅₄₆ ≧ 8.00 (M ≧ 20)

Short arc type discharge lamp, characterized in that to determine comprises or includes at least any one condition is satisfied spectral distribution characteristic, or the characteristic of the illuminance change rate derived from such spectral distribution characteristics of the Inspection method.

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