A high-pressure gas discharge lamp and its laser driving device

Abstract

The present invention discloses a high-pressure gas discharge lamp and a laser driving device thereof, belonging to the technical field of gas discharge lamps. The lamp comprises a lamp housing, a first lamp pole, a second lamp pole, an anode, a cathode, and a cooling device. The first lamp pole and the second lamp pole are respectively located at the anode end and the cathode end of the lamp housing. The anode and the cathode are arranged in a discharge chamber and are located in the axial direction of the lamp housing. They are electrically connected to the connecting pieces at both ends through the first lamp pole and the second lamp pole, respectively. The plasma center is located above the center of the lamp housing. The distances from the anode and the cathode to the center of the lamp housing are set to d1 and d2, respectively, where d1>d2, preferably d1 / d2>2 and d1+d2>18mm. The cooling device is a double-layer conical tube structure with a plurality of small holes at the bottom, which are aligned to cool the lamp housing around the plasma center. The present invention can effectively cool the gas discharge lamp, keeping the gas discharge lamp within a safe temperature range during operation, thereby improving the reliability of the gas discharge lamp and extending its service life.

Description

Technical Field

[0001] The present invention relates to the field of gas discharge lamps, and in particular to a high-pressure gas discharge lamp and a laser driving device thereof. Background Art

[0002] Laser-driven high-pressure gas discharge lamps are widely used in fields such as semiconductor defect detection. They are typically equipped with a dedicated lamp housing system. A laser beam is diverged and then shines on a reflector bowl. After reflection, it is focused at the center of the high-pressure gas discharge lamp, ionizing the gas inside the lamp to form a plasma that emits light. When the high-pressure gas discharge lamp is started, a high voltage is applied between the cathode and anode to facilitate plasma formation. Once started, the plasma is maintained by the laser, eliminating the need for high voltage. The light emitted by the plasma is collected by the reflector bowl and shines on a dichroic mirror. This mirror then reflects the light and separates it from the laser beam for output.

[0003] The electrodes of this type of high-pressure gas discharge lamp only play a supporting role during the startup phase. During stable operation, there is no emission or reception of electrons between the electrodes, thus reducing damage to the electrodes and extending the life of the high-pressure gas discharge lamp. Because this type of high-pressure gas discharge lamp uses a laser beam to provide energy to maintain plasma luminescence, the plasma is concentrated in a smaller area, resulting in a higher temperature at the center of the plasma and a higher proportion of ultraviolet light in the emitted light. In addition, because this type of high-pressure gas discharge lamp is installed vertically with the anode end at the top, the hot air flow within the lamp causes the anode and the surrounding lamp housing to reach higher temperatures, necessitating targeted cooling. Otherwise, the temperature gradient will exceed the tolerance limit of the material, affecting the performance and life of the high-pressure gas discharge lamp. Summary of the Invention

[0004] The present invention aims to provide a high-pressure gas discharge lamp and a laser driving device.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is: a high-pressure gas discharge lamp, comprising a lamp housing, the middle part of which is enclosed to form a discharge chamber; a first lamp pole, which is arranged at the anode end of the lamp housing; an anode, which is connected to the first lamp pole and is located in the discharge chamber; a second lamp pole, which is arranged at the cathode end of the lamp housing; a cathode, which is connected to the second lamp pole and is located in the discharge chamber; the distance from the anode to the center of the lamp housing is set to d1, and the distance from the cathode to the center of the lamp housing is set to d2, and d1>d2.

[0006] In one embodiment, d1 / d2>2 and d1+d2>18 mm.

[0007] In one embodiment, an air filling port is further included, and the air filling port is arranged at the end of the lamp housing.

[0008] In one embodiment, the gas filling port is provided at the cathode end of the lamp housing.

[0009] In one embodiment, a sealing member and a connecting member are further included, wherein the first lamp pole and the second lamp pole are fixedly connected to the lamp housing via the sealing member respectively; and the connecting member is connected to the sealing member.

[0010] In one embodiment, a cooling device is further included, and the cooling device is installed at the anode end of the lamp housing.

[0011] In one embodiment, the cooling device includes an inner shell, an outer shell, an air duct and an air outlet, the outer shell is mounted on the outside of the inner shell, the top and bottom of the inner shell and the outer shell are connected to each other, and the bottom diameter of the outer shell is the same as the maximum transverse diameter of the discharge chamber; the gap between the inner shell and the outer shell forms the air duct, and a plurality of air outlets are evenly arranged at the bottom of the inner shell and the outer shell, aligned with the lamp shell around the center of the plasma.

[0012] In one embodiment, the cooling device further includes an air inlet and a mounting portion, wherein the air inlet is provided on the outer shell and connected to the air duct; the mounting portion is provided on the top of the inner shell and the outer shell; and the cooling device is mounted on the anode end of the lamp housing through the mounting portion.

[0013] The present invention also provides a laser driving device, comprising any of the above-mentioned high-pressure gas discharge lamps.

[0014] In one embodiment, the laser driving device also includes a lamp house system, which includes a laser, a beam expander, a reflector, a dichroic mirror and a reflective bowl. The laser, the beam expander and the reflector are arranged on a horizontal straight line, and the reflector, the dichroic mirror and the reflective bowl are arranged in sequence on a vertical straight line. The high-pressure gas discharge lamp is installed in the reflective bowl along the vertical direction through the connecting piece. The inner surface of the reflective bowl is an ellipsoidal surface, and the center of the high-pressure gas discharge lamp coincides with the focus of the ellipsoidal surface.

[0015] The high-pressure gas discharge lamp proposed in the present invention reduces plasma burning of the anode and lowers the anode temperature by adjusting the distance between the anode and the cathode and adopting an asymmetric layout. A cooling device is also provided to precisely cool the lamp housing around the plasma center, effectively reducing the temperature of the high-pressure gas discharge lamp and keeping it within a safe temperature range during operation, thereby improving the reliability of the high-pressure gas discharge lamp and extending its service life.

[0016] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the laser driving device of the present invention;

[0018] Figure 2 is a schematic cross-sectional view of a high-pressure gas discharge lamp of the present invention;

[0019] Figure 3 Schematic diagram of the cooling device.

[0020] 1-laser driving device; 11-lamp room system; 111-laser; 112-beam expander; 113-reflector; 114-dichroic mirror; 115-reflective bowl; 12-high-pressure gas discharge lamp; 121-lamp housing; 1211-discharge chamber; 1212-first side tube; 1213-second side tube; 122-inflating port; 123-first lamp pole; 124-second lamp pole; 125-anode; 126-cathode; 127-sealing member; 128-fixing member; 129-cooling device; 1291-inner shell; 1292-outer shell; 1293-air duct; 1294-air inlet; 1295-air outlet; 1296-installation part.

[0021] In the drawings, like reference numerals refer to the same drawing elements. DETAILED DESCRIPTION

[0022] In order to make the purpose and technical solution of the embodiment of the present invention clearer, the following will be combined with the appended drawings of the embodiment of the present invention. Figure 1 -Attached Figure 3 , clearly and completely describing the technical solutions of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the described embodiments of the present invention, all other embodiments derived by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the present invention, for the sake of clarity, the following explanation is made: the observer faces the Figure 1 For observation, the upper end of the discharge lamp is the "anode end" and the lower end is the "cathode end". For the convenience of explanation, the up and down, left and right directions in the manual correspond to the observer facing the adjacent Figure 1 The above description is only for the purpose of clearly describing the present invention, and does not indicate or imply that the structures or components referred to must have a specific orientation or be constructed in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] like Figure 1As shown, a laser driving device 1 is used to detect tiny nano-scale defects. The laser driving device 1 includes a lamp chamber system 11 and a high-pressure gas discharge lamp 12. The high-pressure gas discharge lamp 12 is used to detect nano-scale defects in semiconductor wafers. The high-pressure gas discharge lamp 12 is installed in the lamp chamber system 11 in a vertical direction. The lamp chamber system 11 emits a laser beam, which is reflected and focused to make the high-pressure gas discharge lamp 12 emit light. The light emitted by the high-pressure gas discharge lamp 12 is then reflected and output.

[0025] The lamp house system 11 includes a laser 111, a beam expander 112, a reflector 113, a dichroic mirror 114 and a reflector 115. The laser 111 emits a laser beam. The laser 111, the beam expander 112 and the reflector 113 are arranged on a horizontal straight line, and the reflector 113 is tilted. The dichroic mirror 114 and the reflector 115 are arranged in sequence below the reflector 113 and are located on a vertical straight line with the dichroic mirror 114. The dichroic mirror 114 and the reflector 113 are tilted in opposite directions. The high-pressure gas discharge lamp 12 is installed in the reflector 115 in a vertical direction, with the upper end being the anode end and the lower end being the cathode end. The inner surface of the reflector 115 is an ellipsoidal surface, and the center of the high-pressure gas discharge lamp 12 coincides with the focus of the ellipsoidal surface of the reflector 115.

[0026] The laser 111 emits a laser beam, which diverges at a certain angle after passing through the beam expander 112. The laser beam is then reflected by the reflector 113, passes through the dichroic mirror 114, and illuminates the inner surface of the reflective bowl 115. The equivalent focal point of the laser beam and the center of the high-pressure gas discharge lamp 12 are located at the two focal points of the ellipsoidal surface of the reflective bowl 115, respectively. After being focused, the high-power laser beam ionizes the gas within the high-pressure gas discharge lamp 12 to form a plasma. During the startup phase, applying high voltage to both ends of the high-pressure gas discharge lamp 12 facilitates plasma formation. During the stable operation phase, the high-temperature plasma continuously emits light across a continuous spectrum. The higher the temperature, the stronger the ultraviolet component of the emission spectrum. The light emitted by the high-pressure gas discharge lamp 12 is collected by the reflective bowl 115 and reflected by the dichroic mirror 114 for output. Before being output, the emitted light may also pass through a homogenizing device, a collimating device, and the like.

[0027] Please combine Figure 1 and Figure 2The upper end of the high-pressure gas discharge lamp 12 is the anode end, and the lower end is the cathode end. The high-pressure gas discharge lamp 12 includes a lamp housing 121, a gas filling port 122, a first lamp pole 123, a second lamp pole 124, an anode 125, a cathode 126, a sealing member 127 and a fixing member 128. The lamp housing 121 is a symmetrical hollow structure. The two ends of the lamp housing 121 are tubular and the middle is bulb-shaped. The external laser is focused on the center O of the lamp housing 121.

[0028] Reference Figure 2 The gas filling port 122 is disposed at the end of the lamp housing 121. Preferably, the gas filling port 122 is disposed at the cathode end of the lamp housing 121. The gas filling port 122 is used to fill the lamp housing 121 with gas, and the gas filling port 122 is sealed after filling. The gas filling port 122 is generally disposed in the middle portion of the lamp housing 121. However, this arrangement destroys the continuity of the lamp housing 121, causing stress concentration, which can easily cause the high-pressure gas discharge lamp 12 to burst under high temperature and high pressure conditions. By shifting the gas filling port 122 from the middle portion of the lamp housing 121 to the cathode end of the lamp housing 121, the continuity of the lamp housing 121 is maintained, and the pressure resistance of the lamp housing 121 is improved. Furthermore, during operation, the high-pressure gas discharge lamp 12 is generally exposed to high temperatures, with the anode end having a relatively higher temperature. The gas filling port 122 is located at the cathode end, where the temperature is lower than that of the anode end, thereby reducing the probability of the lamp housing 121 bursting.

[0029] Please combine Figure 1 and Figure 2 The first lamp post 123 and the second lamp post 124 are respectively disposed within the lamp housing 121, located on the axis of the lamp housing 121, and located at the anode and cathode ends of the lamp housing 121, respectively. The first lamp post 123 is an anode lamp post, and the second lamp post 124 is a cathode lamp post. The anode 125 is provided at one end of the first lamp post 123 near the center of the lamp housing 121, and the cathode 126 is provided at the second lamp post 124 near the center of the lamp housing 121. The anode 125 and the cathode 126 are disposed opposite each other and are located on the axis of the lamp housing 121. When the external laser is focused on the center O of the lamp housing 121, the laser focus coincides with the center O of the lamp housing 121, the plasma center P is located above the laser focus, the distance from the anode 125 to the center O of the lamp housing 121 is set to d1, and the distance from the cathode 126 to the center O of the lamp housing 121 is set to d2, d1>d2, preferably, d1 / d2>2 and d1+d2>18mm, this asymmetric setting can reduce the burning of the anode 125 by the plasma, thereby reducing the temperature of the anode 125.

[0030] Reference Figure 2The two sealing members 127 are respectively connected to the tail ends of the first lamp pole 123 and the second lamp pole 124, and the sealing members 127 are installed at the two end ports of the lamp housing 121. The first lamp pole 123 and the second lamp pole 124 are fixed in the lamp housing 121 through the sealing members 127. The sealing members 127 are used to seal the connection positions of the first lamp pole 123, the second lamp pole 124 and the lamp housing 121, balance the thermal expansion coefficients between the first lamp pole 123, the second lamp pole 124 and the lamp housing 121, so as to maintain the sealing of the high-pressure gas discharge lamp 12 in the lit and non-lit states, and prevent the gas filled in the lamp housing 121 from leaking; the fixing member 128 is connected to the sealing member 127, and the fixing member 128 is used to install the high-pressure gas discharge lamp 12 at a specific position of the lamp chamber system 11; the cooling device 129 is installed at the anode end of the lamp housing 121.

[0031] Reference Figure 2 The lamp housing 121 includes a discharge chamber 1211, a first side tube 1212 and a second side tube 1213. The center of the lamp housing 121 is surrounded by the discharge chamber 1211, and the discharge chamber 1211 is filled with a gas of specific composition and pressure. The two sides of the discharge chamber 1211 are respectively connected to the first side tube 1212 and the second side tube 1213. The first lamp pole 123 is arranged in the first side tube 1212 and extends in the direction of the discharge chamber 1211, so that the anode 125 is located in the discharge chamber 1211; the second lamp pole 124 is arranged in the second side tube 1213 and extends in the direction of the discharge chamber 1211, so that the cathode 126 is located in the discharge chamber 1211. The inflation port 122 is arranged on the second side tube 1213; the cooling device 129 is mounted on the outside of the first side tube 1212, and the cooling device 129 can be an air cooling device. The air outlet position of the cooling device 129 is aligned with the discharge chamber 1211. Furthermore, the air outlet position of the cooling device 129 is aligned with the periphery of the plasma center P.

[0032] Please combine Figure 2 and Figure 3The cooling device 129 is a conical double-layer structure as a whole, including an inner shell 1291, an outer shell 1292, an air duct 1293, an air inlet 1294, an air outlet 1295 and a mounting portion 1296. The outer shell 1292 is sleeved on the outside of the inner shell 1291. The top and bottom of the inner shell 1291 and the outer shell 1292 are connected to each other. The vertical length of the outer shell 1292 is greater than the vertical length of the inner shell 1291. The bottoms of the inner shell 1291 and the outer shell 1292 form a stepped shape, so that the bottom of the inner shell 1291 is aligned with the anode 125, and the bottom of the outer shell 1292 The diameter is the same as the maximum transverse diameter of the discharge chamber 1211, and the bottom of the outer shell 1292 is aligned with the discharge chamber 1211; the gap between the inner shell 1291 and the outer shell 1292 forms the air duct 1293; the outer shell 1292 is provided with the air inlet 1294, and the air inlet 1294 is connected to a pipeline (not shown in the figure), and the air inlet 1294 is connected to the air duct 1293; a plurality of air outlets 1295 are evenly arranged at the bottom of the inner shell 1291 and the outer shell 1292, and cold air is input from the air inlet 1294, passes through the air duct 1293 and flows out from the air outlet 1295. Because the plasma center P is located above the laser focus, the cold air output from the air outlet 1295 is directed toward the discharge chamber 1211 to cool it. Furthermore, the air outlet 1295 located on the inner shell 1291 is directed toward the area surrounding the anode 125 for cooling, and the air outlet 1295 located on the outer shell 1292 is directed toward the area surrounding the plasma center P for cooling. The air outlet 1295 can precisely deliver the cold air to the area with the highest temperature in the lamp housing 121. The air outlet 1295 is preferably a small hole with a diameter of 0.5 mm. A small diameter of the air outlet 1295 has a higher flow rate and a better cooling effect. The mounting portion 1296 is mounted on the top of the inner shell 1291 and the outer shell 1292. The cooling device 129 is mounted on the anode end of the lamp housing 121 via the mounting portion 1296. Specifically, the cooling device 129 can be mounted, but is not limited to, by threading the mounting portion 1296 and the fixing member 128.

[0033] The high-pressure gas discharge lamp proposed in the present invention reduces plasma burning of the anode and lowers the anode temperature by adjusting the distance between the anode and the cathode and adopting an asymmetric layout. A cooling device is also provided to precisely cool the lamp housing around the plasma center, effectively reducing the temperature of the high-pressure gas discharge lamp and keeping it within a safe temperature range during operation, thereby improving the reliability of the high-pressure gas discharge lamp and extending its service life.

[0034] Although the present invention has been disclosed above with reference to the embodiments, they are not intended to limit the present invention. Anyone with ordinary skill in the art may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent applications.

Claims

1. A high-pressure gas discharge lamp, characterized in that: include A lamp housing, wherein the middle portion of the lamp housing is arranged to form a discharge chamber; a first lamp pole, the first lamp pole being arranged at the anode end of the lamp housing; an anode connected to the first lamp pole and located in the discharge chamber; a second lamp pole, the second lamp pole being arranged at the cathode end of the lamp housing; a cathode connected to the second lamp pole and located in the discharge chamber; The anode and the cathode are arranged facing each other, the distance from the anode to the center of the lamp housing is set to d1, the distance from the cathode to the center of the lamp housing is set to d2, d1>d2, d1 / d2>2 and d1+d2>18mm.

2. A high pressure gas discharge lamp according to claim 1, characterized in that: It also includes an air filling port, which is arranged at the end of the lamp housing.

3. A high pressure gas discharge lamp according to claim 2, characterized in that: The air filling port is arranged at the cathode end of the lamp housing.

4. A high pressure gas discharge lamp according to claim 1, characterized in that: It also includes a sealing member and a connecting member, the first lamp pole and the second lamp pole are fixedly connected to the lamp housing through the sealing member respectively; the connecting member is connected to the sealing member.

5. The high-pressure gas discharge lamp according to claim 1, wherein: It also includes a cooling device, which is installed at the anode end of the lamp housing.

6. A high pressure gas discharge lamp as claimed in claim 5, characterized in that: The cooling device includes an inner shell, an outer shell, an air duct and air outlets. The outer shell is sleeved on the outside of the inner shell. The top and bottom of the inner shell and the outer shell are connected to each other. The bottom diameter of the outer shell is the same as the maximum transverse diameter of the discharge chamber. The gap between the inner shell and the outer shell forms the air duct. The multiple air outlets are evenly arranged on the bottom of the inner shell and the outer shell, and are aligned with the lamp shell around the center of the plasma.

7. A high pressure gas discharge lamp according to claim 6, characterized in that: The cooling device also includes an air inlet and a mounting portion, wherein the air inlet is provided on the outer shell and connected to the air duct; the mounting portion is provided on the top of the inner shell and the outer shell; the cooling device is mounted on the anode end of the lamp housing through the mounting portion.

8. A laser driving device, characterized in that: The high-pressure gas discharge lamp comprises the high-pressure gas discharge lamp described in any one of claims 1-7.

9. The laser driving device according to claim 8, wherein: It also includes a lamp house system, which includes a laser, a beam expander, a reflector, a dichroic mirror and a reflective bowl. The laser, the beam expander and the reflector are arranged on a horizontal straight line, and the reflector, the dichroic mirror and the reflective bowl are arranged in sequence on a vertical straight line. The high-pressure gas discharge lamp is installed in the reflective bowl in a vertical direction. The inner surface of the reflective bowl is an ellipsoidal surface, and the center of the high-pressure gas discharge lamp coincides with the focus of the ellipsoidal surface.

Images