Method for removing active metal impurities in wall of quartz tube, quartz tube and high-pressure discharge lamp

Abstract

The invention provides a method for removing active metal impurities in a quartz tube wall, a quartz tube and a high-pressure discharge lamp. The method comprises the following steps: S1, moderately heating a quartz tube, and activating molecular tissues of the quartz tube; and S2, when the quartz tube is heated, negative high voltage is loaded on the peripheral surface (11) of the quartz tube, so that active metal impurities in the wall (12) of the quartz tube penetrate through gaps of the quartz molecular tissues to be discharged to the peripheral surface (11) of the quartz tube under the action of an electric field. When the quartz tube prepared by the method is used for the high-pressure discharge lamp, the problems that the sealing strength of the metal foil (4) and the quartz tube (6) is reduced and the high-pressure discharge lamp leaks air and is poor in fracture due to the fact that active metal impurities in the quartz tube wall (12) are gathered on the surface of the metal foil (4) in the lighting process of the high-pressure discharge lamp can be prevented, and the service life of the high-pressure discharge lamp is prolonged.

Description

Technical Field

[0001] The present invention relates to the optoelectronic field, and particularly to a method for removing active metal impurities in a quartz tube wall and a quartz tube prepared by using the method; the present invention also relates to a high-pressure discharge lamp using the above quartz tube. Background Art

[0002] In a high-pressure discharge lamp widely used in optical devices such as ultraviolet exposure, a pair of positive and negative electrodes are oppositely arranged in a discharge container made of a quartz tube. One end of the positive and negative electrodes is buried in the quartz tube and connected to an external power supply wire through a metal foil. The metal foil and the quartz tube are heat-sealed by an external heat source to form a relatively sealed quartz discharge container. The quartz discharge container is filled with at least 0.03 mg / mm3 of mercury, a gas with a pressure not lower than 20 kPa, and 1×10−8 mol / cm3 to 1×10−3 mol / cm3 of halogen.

[0003] During the lighting process of the above high-pressure discharge lamp, active metal impurities (such as Na+, K+) in the quartz tube wall near the metal foil on the negative electrode side are attracted to the surface of the metal foil under the action of the electric field, resulting in a decrease in the sealing strength between the metal foil and the quartz tube, causing the metal foil to peel off from the quartz tube, and further resulting in a poor rupture of the high-pressure discharge lamp.

[0004] Currently, the main solutions to the above-mentioned problems in the prior art are as follows:

[0005] 1. Removing metal impurities on the inner and outer surfaces of the quartz tube by chemical cleaning. For example, the quartz tube is immersed in a strong acidic liquid medicine so that the metal impurities on the inner and outer surfaces of the quartz tube are corroded and removed.

[0006] However, using the above chemical cleaning method can only remove metal impurities on the inner and outer surfaces of the quartz tube, and cannot remove metal impurities in the quartz tube wall.

[0007] 2. A same-potential line is provided on the outer peripheral surface of the quartz tube corresponding to the metal foil on the negative electrode side of the high-pressure discharge lamp, so that the outer peripheral surface of the quartz tube has the same voltage as the metal foil on the negative electrode side when the high-pressure discharge lamp is lit, to inhibit active metal impurities (such as Na+, K+) in the quartz tube wall.

[0008] However, when using the above method of setting equal voltages, active metal impurities (such as Na+, K+) in the quartz tube wall near the same-potential line side will move towards the same-potential line side, that is, the outer peripheral surface of the quartz tube, while active metal impurities (such as Na+, K+) in the quartz tube wall near the metal foil side of the negative electrode will still gather near the metal foil surface, resulting in a decrease in the sealing strength between the metal foil and the quartz tube, and then the metal foil peels off from the quartz tube, and further the discharge lamp ruptures poorly.

[0009] Therefore, it is necessary to design a method for removing active metal impurities in a quartz tube wall, a quartz tube prepared by using this method, and a high-pressure discharge lamp using this quartz tube. Summary of the Invention

[0010] In view of the technical defects in the background art, the present invention provides a method for removing active metal impurities in a quartz tube wall, a quartz tube prepared by using this method, and a high-pressure discharge lamp using this quartz tube, which solves the above technical problems and meets the actual requirements. The specific technical solutions are as follows:

[0011] A method for removing active metal impurities in a quartz tube wall includes: Step S1: Heat the quartz tube to activate the molecular structure inside the quartz tube. Step S2: Apply a negative high voltage to the outer peripheral surface of the quartz tube relative to the inner surface of the quartz tube, so that the active metal impurities in the quartz tube wall are discharged to the outer peripheral surface of the quartz tube through the gaps between the quartz molecular structures under the action of the electric field. Further, in step S1, when heating the quartz tube, the heating temperature is lower than the softening point temperature of the quartz tube. Further, in step S2, the value of the negative high voltage is: equal to or greater than the critical voltage value for breaking down the quartz tube wall. Further, the operation steps of applying the negative high voltage in step S2 include arranging a metal component on the inner surface of the quartz tube, and connecting the metal component to the positive electrode terminal of a negative DC high-voltage power supply. Arranging a metal part on the outer peripheral surface of the quartz tube, and connecting the metal part to the negative terminal of the negative DC high-voltage power supply.

[0012] A quartz tube in which the active metal impurities in the wall of the entire or partial region of the quartz tube are removed.

[0013] A high-pressure discharge lamp includes a discharge container made of a quartz tube. A pair of positive and negative electrodes are oppositely arranged in the discharge container. One end of each of the positive and negative electrodes is connected to an external power supply wire through a metal foil. A nested quartz tube is used for transition between the metal foil and the discharge container. A relatively sealed discharge space is formed by the mutual fusion of the metal foil, the nested quartz tube, and the discharge container. Further, at least 0.03 mg / mm3 of mercury, a gas with a pressure not lower than 20 kPa, and 1×10−8 mol / cm3 to 1×10−3 mol / cm3 of halogen are filled in the discharge container. Further, the active metal impurities in the wall of the nested quartz tube are removed.

[0014] Compared with the prior art, a method for removing active metal impurities in a quartz tube wall provided by the present invention, a quartz tube prepared by using this method, and a high-pressure discharge lamp using this quartz tube have the following beneficial effects: When the quartz tube prepared by the removal method in the present invention is fused with a metal foil in a high-pressure discharge lamp, it can prevent the decrease in the bonding strength between the metal foil and the quartz tube (i.e., air leakage and cracking defects of the high-pressure discharge lamp) caused by the accumulation of active metal impurities in the quartz tube wall on the surface of the metal foil on the negative electrode side of the high-pressure discharge lamp during the lighting process of the high-pressure discharge lamp, and improve the service life of the high-pressure discharge lamp. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of a method for removing active metal impurities in a quartz tube wall in the present invention.

[0016] Figure 2 It is a schematic diagram of a method for removing active metal impurities in a quartz tube wall during the manufacturing process of a high-pressure discharge lamp in the present invention.

[0017] Figure 3 It is a schematic diagram of the structure of a high-pressure discharge lamp manufactured by implementing the method of the present invention.

[0018] Figure 4 It is a schematic diagram of the structure of a general high-pressure discharge lamp not manufactured by implementing the method of the present invention.

[0019] Among them, 1. Discharge container, 11. Outer peripheral surface of the quartz tube, 12. Inside the quartz tube wall, 13. Inner surface of the quartz tube, 100. High-voltage power supply, 101. Metal component, 102. Metal part, 103. Load resistor R, 1000. High-pressure discharge lamp, 2. Positive electrode, 3. Negative electrode, 4. Metal foil, 5. Power supply wire, 6. Nested quartz tube, 7. Mercury. DETAILED DESCRIPTION OF THE INVENTION

[0020] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "middle", "inner", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0021] The embodiments of the present invention will be described below in conjunction with the accompanying drawings and related embodiments. The embodiments of the present invention are not limited to the following embodiments, and the present invention relates to the relevant necessary components in the technical field, which should be regarded as well-known technologies in the technical field and can be known and mastered by those skilled in the technical field.

[0022] Refer to Figure 1-2 , a method for removing active metal impurities in a quartz tube wall (12), comprising: Step S1: Heat the quartz tube (1) to activate the molecular structure inside the quartz tube. The heating temperature is below the softening point temperature of the quartz tube (1) (about 1300 °C). In this embodiment, the temperature of the quartz tube near the metal foil (4) on the negative electrode (3) side during the lighting operation of the high-pressure discharge lamp (1000) (500 ± 50 °C) is selected as the heating temperature. Step S2: Apply a negative high voltage to the outer peripheral surface (11) of the quartz tube relative to the inner surface (13) of the quartz tube, so that the active metal impurities in the quartz tube wall are discharged to the outer peripheral surface (11) of the quartz tube through the gaps between the quartz molecular structures under the action of the electric field. The specific operation of applying the negative high voltage is as follows: A metal rod (101) is arranged on the inner surface (13) of the quartz tube. The metal rod (101) is connected to the positive terminal of the negative DC high-voltage power supply (100). The metal rod (101) may be other metal components with equivalent functions. For example, it may be composed of Figure 2As shown, the metal combination composed of the negative electrode (3), the metal foil (4), and the external power supply wire (5). To prevent contamination of the quartz tube (1), in this embodiment, the metal rod (101) is selected as a tungsten rod made of the same material as the high-voltage discharge lamp electrode 1000. As Figure 1 As shown, a metal sheet (102) is provided on the outer peripheral surface (11) of the quartz tube. The metal sheet (102) is connected to the negative terminal of the negative DC high-voltage power supply (100). The metal sheet (102) can be other metal components with equivalent functions. For example, it can be a metal winding (such as a copper wire) wound around the outer peripheral surface (11) of the quartz tube. In this embodiment, the metal sheet (102) is selected as a copper sheet.

[0023] In the above embodiment of the present invention, the negative high-voltage value in step S2 is: equal to or greater than the critical voltage value for breaking through the quartz tube wall. According to the test device used in this embodiment, when the wall thickness of the quartz tube is 1 mm, the breakdown critical voltage is about -1.5 KV, and when the wall thickness of the quartz tube is 3 mm, the breakdown critical voltage is about -3.8 KV. Taking the quartz tube with a wall thickness of 3 mm as an example, we select the negative DC high-voltage value of -4 KV.

[0024] To prevent the large current from damaging the circuit loop and excessively damaging the quartz tube tissue after breaking through the quartz tube, the inventor inserts a load resistor R (103) into the circuit loop to control only a micro current to pass through the circuit loop.

[0025] The negative DC voltage loading time is based on the premise of fully removing the active metal impurities in the quartz tube wall (12). It can be any interval during the heating process of the quartz tube (1). In this embodiment, the negative DC high-voltage loading time is selected from the start of heating of the quartz tube (1) to the start of cooling of the heating structure of the quartz tube (1), for a total of 9 minutes.

[0026] A quartz tube prepared by the above method, in which the active metal impurities in the wall of all or part of the quartz tube are removed. The quartz tube is not limited to the raw material state of the quartz tube and can be other forms presented by the quartz tube during the preparation process of the high-voltage discharge lamp (1000). For example, it can be the form of the quartz tube after being assembled and processed with the negative electrode (3), the metal foil (4), and the external power supply wire (5) (as Figure 2 shown)

[0027] The active metal impurities discharged to the outer peripheral surface (11) of the metal by the action of the electric field can be removed by cleaning with a chemical liquid (such as hydrofluoric acid).

[0028] Next, the detection of the high-voltage discharge lamp ([[]] Figure 3 ) using the quartz tube prepared by the above embodiment as the nested quartz tube (6) will be described:

[0029] A high-pressure discharge lamp prepared by using the quartz tube prepared in the above embodiment as the nested quartz tube (6). Figure 3 ) characterized in that a pair of positive electrodes (2) and negative electrodes (3) are oppositely arranged in a discharge container (1) made of a quartz tube, one end of the positive and negative electrodes (2, 3) is connected to an external power supply wire (5) through a metal foil (4), the metal foil (4) and the discharge container are transitioned through the nested quartz tube (6), and a relatively sealed discharge space is formed by the mutual fusion of the metal foil (4), the nested quartz tube (6) and the discharge container (1).

[0030] In an embodiment of the present invention, at least 0.03 mg / mm3 of mercury (7), a gas with a pressure not lower than 20 kPa, and 1×10-8 mol / cm3 to 1×10-3 mol / cm3 of halogen are filled in the discharge container (1).

[0031] In an embodiment of the present invention, the active metal impurities in the nested quartz tube (6) are removed.

[0032] Since the active metal impurities in the nested quartz tube (6) in close contact with the metal foil (4) in the above high-pressure discharge lamp (1000) are removed, when the high-pressure discharge lamp (1000) is lit, it can avoid the decrease in the bonding strength between the metal foil (4) and the quartz tube caused by the accumulation of active metal impurities in the quartz tube near the metal foil (4) on the surface of the metal foil (4), thereby preventing the leakage and rupture of the high-pressure discharge lamp (1000) caused by this, and improving the service life of the high-pressure discharge lamp (1000).

[0033] For the purpose of comparison, the inventor installed and tested the high-pressure discharge lamp prepared in the embodiment of the present invention and a general high-pressure discharge lamp (a high-pressure discharge lamp that does not use the quartz tube prepared in the embodiment of the present invention, hereinafter referred to as a general high-pressure discharge lamp) under the same conditions.

[0034] Comparison table of lighting life test of the high-pressure discharge lamp in the embodiment of the present invention and the general high-pressure discharge lamp: Note: "O" indicates that there is no poor peeling between the metal foil and the quartz tube, nor is there any leakage or rupture of the high-pressure discharge lamp caused by the peeling between the metal foil and the quartz tube. "△" indicates that there is a peeling phenomenon between the metal foil and the quartz tube. "X" indicates that the high-pressure discharge lamp leaks or ruptures due to the peeling between the metal foil and the quartz tube.

[0033] As can be seen from the table, in the high-pressure discharge lamp fabricated according to the embodiment of the present invention, no peeling of the metal foil (4) from the nearby quartz tube (i.e., the nested quartz tube 6) occurred during continuous lighting for 2000 h, nor did problems such as air leakage or rupture of the high-pressure discharge lamp caused thereby. In contrast, for a general high-pressure discharge lamp, peeling of the metal foil (4) from the nearby quartz tube can be observed within 100 h of lighting, and the failure rate of air leakage or rupture of the high-pressure discharge lamp due to the peeling of the metal foil (4) from the nearby quartz tube within 2000 h of lighting is 30%.

[0034] Through the above tests, it can be confirmed that when the quartz tube prepared by the method of the present invention is used as the nested quartz tube (6) in a high-pressure discharge lamp for 1000 hours, it can effectively avoid the decrease in the bonding strength between the metal foil (4) and the quartz tube and problems such as air leakage and rupture of the high-pressure discharge lamp caused by the accumulation of active metal impurities in the quartz tube wall on the surface of the metal foil (4) on the negative electrode (3) side of the high-pressure discharge lamp, thereby improving the service life of the high-pressure discharge lamp.

[0035] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for removing active metal impurities inside a quartz tube wall (12), characterized in that, Including: Step S1: Heat the quartz tube to activate the molecular structure of the quartz tube; Step S2: During the heating of the quartz tube, apply a negative high voltage to the outer peripheral surface (11) of the quartz tube, so that the active metal impurities inside the quartz tube wall (12) are discharged to the outer peripheral surface (11) of the quartz tube through the gaps in the quartz molecular structure under the action of the electric field.

2. A method for removing active metal impurities in a quartz tube wall (12) according to claim 1, characterized in that, In step S1, the quartz tube is heated, and the heating temperature is lower than the softening point temperature of the quartz tube.

3. A method for removing active metal impurities in a quartz tube wall (12) according to claim 1, characterized in that, In step S2, the value of the negative high voltage is: equal to or greater than the critical voltage value for breaking through the quartz tube wall.

4. A method for removing active metal impurities in a quartz tube wall (12) according to claim 1, characterized in that, The operation step of applying the negative high voltage in step S2 includes arranging a metal component (101) on the inner surface (13) of the quartz tube, and connecting the metal component (101) to the positive terminal of the negative DC high voltage power supply (100); arranging a metal part (102) on the outer peripheral surface (11) of the quartz tube, and connecting the metal part (102) to the negative terminal of the negative DC high voltage power supply (100).

5. A quartz tube prepared by the method according to any one of claims 1-4, characterized in that, The active metal impurities in the wall of the whole or partial area of the quartz tube are removed.

6. A high-pressure discharge lamp prepared by using the quartz tube according to claim 5, characterized in that, It includes a discharge container (1) made of a quartz tube, in which a positive electrode (2) and a negative electrode (3) are oppositely arranged. One end of the positive and negative electrodes is connected to an external power supply wire (5) through a metal foil (4). The metal foil (4) and the discharge container (1) are transitioned through a nested quartz tube (6). A relatively sealed discharge space is formed by the mutual fusion of the metal foil (4), the nested quartz tube (6) and the discharge container (1).

7. A high-pressure discharge lamp according to claim 6, characterized in that, The discharge capacitor is filled with at least 0.03 mg / mm 3 of mercury (7), a gas with a pressure of not less than 20 kPa, and 1×10 -8 mol / cm 3 to 1×10 -3 mol / cm 3 of halogen.

8. A high-pressure discharge lamp according to claim 6, characterized in that, The active metal impurities in the nested quartz tube (6) are removed.

Images