JP6495755B2 - UV detector - Google Patents

Description

  The present invention relates to an ultraviolet detector.

  As an ultraviolet detector utilizing the photoelectron emission effect and discharge phenomenon, a light-transmitting container in which discharge gas is enclosed, a cathode discharge part disposed in the container, and a cathode penetrating the sealing part of the container What is equipped with the cathode which has a support part, the anode discharge part arrange | positioned in a container, and the anode which has an anode support part which penetrates the sealing part of a container is known (for example, refer patent document 1). .

JP-A 49-59568

  In the ultraviolet detector as described above, it is preferable to accurately detect light in a predetermined ultraviolet region even under visible light, and the detection sensitivity should be uniformed while suppressing variation among individuals. Is preferred.

  An object of the present invention is to provide an ultraviolet detector that can accurately detect light in a predetermined ultraviolet region even under visible light and can achieve uniform detection sensitivity with a simple configuration. And

  The ultraviolet detector of the present invention has a light-transmitting container having a discharge gas sealed therein, a cathode discharge part arranged in the container, and a rod-like support part penetrating the sealing part of the container A cathode and a rod-like anode having an anode support part disposed in the container and an anode support part penetrating the sealing part, and either the cathode or the anode includes a cathode discharge part and an anode discharge part And the cathode support portion and the anode support portion are opposed to each other at a second interval larger than the first interval, and at least a surface of the cathode discharge portion is provided. The first material to be configured has higher average sensitivity to light in a predetermined ultraviolet region than average sensitivity to light in the visible region, and average sensitivity to light in the visible region as compared with the second material constituting at least the surface of the cathode support portion. Is low.

  In this ultraviolet detector, the first material has a higher average sensitivity to light in a predetermined ultraviolet region than an average sensitivity to light in the visible region, and a lower average sensitivity to light in the visible region than the second material of the cathode support. The cathode discharge part and the anode discharge part are opposed to each other at a first interval smaller than the second interval between the cathode support part and the anode support part. As a result, a region where discharge is likely to occur between the cathode and the anode overlaps with a region having high sensitivity to light in a predetermined ultraviolet region, so that photoelectron emission and discharge caused by light in the visible region are suppressed and visible. Even under light, it is possible to accurately detect light in a predetermined ultraviolet region. Furthermore, since the first interval and the second interval are configured by providing a bent portion on one of the cathode and the anode, for example, compared to a case where the bent portion is provided on both the cathode and the anode, The first interval and the second interval can be configured with high accuracy. As a result, the detection sensitivity can be made uniform with a simple configuration. As described above, according to the ultraviolet detector, light in a predetermined ultraviolet region can be accurately detected even under visible light, and detection sensitivity can be made uniform with a simple configuration.

  In the ultraviolet detector of the present invention, the difference in thermal expansion coefficient between the second material and the container material may be smaller than the difference in thermal expansion coefficient between the first material and the container material. As a result, it is possible to reliably suppress the occurrence of changes in the first interval and the second interval due to a defect in the sealing portion, and to achieve uniform detection sensitivity.

  In the ultraviolet detector of the present invention, the bent portion may be provided on the anode. Thereby, the influence of the bending part with respect to the cathode discharge part used as a photoelectron emission area | region can be suppressed, and the detection sensitivity can be made further uniform.

  In the ultraviolet detector of the present invention, at least a part of the bent portion may face the cathode discharge portion. For example, when the bent portion provided on the anode is provided at a position facing only the cathode support portion, the cathode support portion may face the anode discharge portion at the first interval. Photoelectron emission and discharge due to light in the visible range may occur between the anode discharge portion and the anode discharge portion. By causing at least a part of the bent portion provided on the anode to face the cathode discharge portion, the cathode support portion is spaced apart from the anode by at least the first interval. Ultraviolet light can be detected with higher accuracy.

  In the ultraviolet detector of the present invention, the bent part may be provided in the cathode discharge part. As a result, even if a discharge occurs in the middle of the bent portion, the discharge is caused by light in a predetermined ultraviolet region, so that light in the predetermined ultraviolet region can be detected with higher accuracy.

  In the ultraviolet detector of the present invention, the cathode discharge part may be a rod-shaped member made of the first material. By configuring the cathode discharge part with a rod-shaped member made of the first material, for example, compared to the case where the surface of the cathode discharge part is formed by forming the first material in a film form on a desired substrate. In addition, it is possible to suppress a possibility that the first material is peeled off due to discharge, and to extend the life.

  In the ultraviolet detector of the present invention, the width of the cathode discharge part may be larger than the width of the anode discharge part when viewed from the direction in which the cathode discharge part and the anode discharge part face each other. Thereby, the detection sensitivity with respect to the light of a predetermined ultraviolet region can be made higher.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is under visible light, the ultraviolet detector which can detect the light of a predetermined ultraviolet region accurately and can aim at equalization of detection sensitivity with a simple structure can be provided.

It is sectional drawing of the ultraviolet detector of embodiment. It is the figure which looked at the ultraviolet detector of FIG. 1 from the A direction. It is a graph which shows the spectral sensitivity characteristic in case a cathode discharge part consists of nickel, and a cathode discharge part consists of kovar. It is sectional drawing of the ultraviolet detector of a 1st modification. It is the figure which looked at the ultraviolet detector of FIG. 4 from the B direction. It is sectional drawing of the ultraviolet detector of a 2nd modification. It is sectional drawing of the ultraviolet detector of a 3rd modification. It is sectional drawing of the ultraviolet detector of a 4th modification.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are used for the same or corresponding elements, and duplicate descriptions are omitted.

  As shown in FIGS. 1 and 2, the ultraviolet detector 1 includes a container 10, a cathode 20, and an anode 30. The ultraviolet detector 1 is a sensor that detects light in a predetermined ultraviolet region using a photoelectron emission effect and a discharge phenomenon, and is used as, for example, a flame sensor. In addition, in FIG. 2, the container 10 is permeate | transmitted and the external shape of the container 10 is shown with the virtual line.

  The container 10 has a substantially cylindrical main body portion 11 and a flat sealing portion 12. The container 10 is made of a material having optical transparency (ultraviolet ray transparency) such as Kovar glass. The container 10 is filled with a discharge gas such as neon or argon, and the container 10 is kept airtight.

  The cathode 20 is a rod-shaped electrode having a cathode discharge part 21 disposed in the container 10 and a cathode support part 22 that penetrates the sealing part 12 of the container 10. Each of the cathode discharge part 21 and the cathode support part 22 is a rod-like member having a linear shape and a circular cross section. The diameter of the cathode discharge part 21 is larger than the diameter of the cathode support part 22. The cathode discharge portion 21 is a material (hereinafter referred to as “a material having a higher average sensitivity to light in a predetermined ultraviolet region than the average sensitivity to light in the visible region” and having a lower average sensitivity to light in the visible region than the material of the cathode support portion 22. The first material). Examples of such a first material include metals such as nickel, platinum, and gold. The cathode support part 22 is made of a material different from the cathode discharge part (hereinafter referred to as “second material”). The difference in thermal expansion coefficient between the second material and the material of the container 10 is smaller than the difference in thermal expansion coefficient between the first material and the material of the container 10. An example of such a second material is a metal such as Kovar. The cathode discharge part 21 and the cathode support part 22 are connected to each other on the end face in the longitudinal direction, for example, by welding so that the centers of the cathode discharge part 21 and the cathode support part 22 coincide with each other when viewed from the longitudinal direction (extend coaxially as the cathode 20). ing.

  The cathode support part 22 includes a cathode connection part 24 connected to the cathode discharge part 21, a cathode sealed part 25 sealed (air-tightly sealed) to the sealing part 12 of the container 10, and the outside of the container 10. And a cathode lead portion 26 extending to the surface. The cathode 20 is fixed to the container 10 by sealing the cathode sealed portion 25 to the sealing portion 12 of the container 10. The cathode 20 is fixed so that the cathode discharge portion 21 and the cathode support portion 22 are parallel to the center line C of the container 10. The cathode lead portion 26 is used for electrical connection with an external circuit.

  The anode 30 includes an anode discharge part 31 disposed in the container 10, an anode support part 32 that penetrates the sealing part 12 of the container 10, and a bend provided between the anode discharge part 31 and the anode support part 32. And a bar-shaped electrode having a portion 33. The anode 30 is a member obtained by bending a straight rod-shaped member having a circular cross section into a crank shape at a bending portion 33 so that the axis in the extending direction is shifted between the anode discharge portion 31 and the anode support portion 32. The anode discharge part 31 and the anode support part 32 are formed linearly. The diameter of the anode 30 is smaller than the diameter of the cathode discharge part 21, for example, the same as the diameter of the cathode support part 22. The anode 30 is made of a metal such as Kovar, for example, and may be the same second material as the cathode support portion 22.

  The anode support part 32 includes an anode connection part 34 connected to the bending part 33, an anode sealed part 35 sealed (air-tightly sealed) to the sealing part 12 of the container 10, and an outside of the container 10. An anode lead portion 36 extending therethrough. The anode 30 is fixed to the container 10 by sealing the anode sealed portion 35 to the sealing portion 12 of the container 10. The anode 30 is fixed so that the anode discharge part 31 and the anode support part 32 are parallel to the center line C of the container 10. The anode lead portion 36 is provided for electrical connection with an external circuit.

  The cathode discharge part 21, the cathode support part 22, the anode discharge part 31, the anode support part 32, and the bending part 33 are located on the same plane. The cathode discharge part 21, the cathode support part 22, the anode discharge part 31, and the anode support part 32 are parallel to a predetermined line in the plane (for example, the center line C of the container 10).

  As shown in FIG. 1, the cathode 20 and the anode 30 face each other in a direction orthogonal to the center line C of the container 10. The cathode discharge part 21 and the anode discharge part 31 are opposed to each other at a first distance D1. And the cathode support part 22 and the anode support part 32 which were separated by the bending part 33 are mutually opposed by the 2nd space | interval D2 larger than the 1st space | interval D1. That is, the bent portion 33 is a sealed portion from the end portion of the bent portion 33 on the anode support portion 32 side (the end of the bent portion 33) where the cathode discharge portion 21 and the anode discharge portion 31 face each other at the first interval D1. 12, the anode support portion 22 and the anode support portion 32 are provided on the anode 30 so as to face each other at the second distance D2. The bent portion 33 faces the cathode discharge portion 21 in a direction orthogonal to the center line C of the container 10. More specifically, in the bent portion 33, at least the end portion on the anode discharge portion 31 side (starting end of the bent portion 33) faces the region including the end portion on the sealing portion 12 side in the cathode discharge portion 21. Yes. Therefore, in the end part (boundary part with the cathode support part 22) by the side of the sealing part 12 among the cathode discharge parts 21, the distance between the anodes 30 is larger than 1st space | interval D1, and 2nd space | interval. D2 or less. The tip 21 a of the cathode discharge part 21 and the tip 31 a of the anode discharge part 31 are opposed to each other in a direction orthogonal to the center line C of the container 10.

  As shown in FIG. 2, when viewed from the direction in which the cathode discharge portion 21 and the anode discharge portion 31 face each other (the direction in which the cathode 20 and the anode 30 appear to overlap), the width of the cathode discharge portion 21 is the anode discharge. It is larger than the width of the part 31. Therefore, the cathode discharge portion 21 protrudes from the anode discharge portion 31 when viewed from the direction in which the cathode discharge portion 21 and the anode discharge portion 31 face each other. The width direction of the cathode discharge part 21 and the anode discharge part 31 is a direction orthogonal to the plane on which the cathode discharge part 21, the cathode support part 22, the anode discharge part 31, the anode support part 32, and the bending part 33 are located. is there.

  Next, the characteristics of the first material and the second material will be described. The first material used for the cathode discharge unit 21 is a material having higher average sensitivity to light in a predetermined ultraviolet region (for example, 185 nm to 260 nm) than the average sensitivity to light in the visible region (for example, 400 nm to less than 700 nm). The average sensitivity to light in the visible range is lower than that of the second material used for the cathode support 22. Further, when attention is paid to a value obtained by dividing (dividing) the average sensitivity with respect to the light in the predetermined ultraviolet region by the average sensitivity with respect to the light in the visible region, the value of the first material used for the cathode discharge portion 21 is determined by the cathode support. It is larger than the said value of the 2nd material used for the part 22. FIG. In particular, in this example, the first material has substantially no sensitivity to light in a wavelength range of 260 nm or more (including the visible range and the infrared range). In other words, in photoelectron emission, it can be said that the first material has higher selectivity for light in the ultraviolet region than the second material. In addition, the average sensitivity with respect to light in a predetermined wavelength range is an average value of sensitivity in the wavelength range, for example, an arithmetic average value.

  This will be further described with reference to a specific example. As shown in FIG. 3, when the cathode discharge part 21 is made of nickel which is an example of the first material, the cathode discharge part 21 is sensitive to light in the ultraviolet region of about 252 nm or less. And has no sensitivity to light in a wavelength range greater than about 252 nm. On the other hand, when the cathode discharge part 21 consists of Kovar which is an example of a 2nd material, the cathode discharge part 21 has a sensitivity with respect to the light of a wavelength range larger than about 252 nm. Thus, nickel is a material having a higher average sensitivity to light in a predetermined ultraviolet region (about 252 nm or less) than the average sensitivity to light in the visible region (that is, “0”), and in the visible region as compared to Kovar. It is a material with low average sensitivity to light.

  Next, the operation principle of the ultraviolet detector 1 will be described. In use, a voltage is supplied between the cathode 20 and the anode 30. Since the cathode discharge portion 21 and the anode discharge portion 31 face each other close to each other at the first interval D1, the discharge is easily generated between the cathode 20 and the anode 30 and functions as a discharge region. On the other hand, the cathode support part 22 and the anode support part 32 are opposed to each other with a second distance D2, and thus hardly function as a discharge region. When light in a predetermined ultraviolet region is incident on the cathode discharge part 21 through the container 10 in the use state, photoelectrons are emitted from the cathode discharge part 21 (photoelectron emission effect). The photoelectrons are attracted to the anode discharge portion 31 and collide with the discharge gas molecules in the container 10 to ionize the discharge gas molecules. Of the electrons and positive ions generated by ionization, the electrons further collide with other discharge gas molecules and ionize to reach the anode discharge portion 31. On the other hand, positive ions are accelerated toward the anode discharge part 31 and collide with the anode discharge part 31 to generate many secondary electrons. By repeating the above phenomenon, a current flows between the cathode 20 and the anode 30, and a discharge state is obtained. The ultraviolet detector 1 detects light in a predetermined ultraviolet region using a photoelectron emission effect and a discharge phenomenon.

  As described above, in the ultraviolet detector 1, the average sensitivity for light in the predetermined ultraviolet region is higher than the average sensitivity for light in the visible region, and the average for visible light compared to the second material of the cathode support portion 22. A first material with low sensitivity is used for the cathode discharge part 21, and the cathode discharge part 21 and the anode discharge part 31 are separated from each other by a second distance D 2 between the cathode support part 22 and the anode support part 32 in the sealing part 12. The first interval D1 is smaller than the first interval D1. As a result, a region where discharge is likely to occur between the cathode 20 and the anode 30 overlaps a region sensitive to light in a predetermined ultraviolet region, so that photoelectron emission and discharge caused by light in the visible region are suppressed. Even under visible light, light in a predetermined ultraviolet region can be detected with high accuracy. Furthermore, since the bent portion 33 is provided in the anode 30, for example, the first interval D1 and the second interval D2 can be accurately set as compared with the case where the bent portion 33 is provided in both the cathode 20 and the anode 30. Can be configured. As a result, the detection sensitivity can be made uniform with a simple configuration. As described above, according to the ultraviolet detector 1, light in a predetermined ultraviolet region can be accurately detected even under visible light, and detection sensitivity can be made uniform with a simple configuration. Further, since a material different from that of the cathode discharge part 21 is used for the cathode support part 22, the material suitable for sealing at the sealing part 12 is selected as the material of the cathode support part 22. It is possible to prevent the discharge gas from escaping from the portion 12 and to extend the life.

  For example, the wavelength range of the gas burner flame (city gas) is greater than about 185 nm, and the wavelength range of sunlight is greater than about 280 nm. Further, the wavelength range of light output from the tungsten bulb is larger than about 300 nm. Therefore, according to the ultraviolet detector 1, even in the presence of sunlight or light output from a tungsten bulb, it is possible to accurately detect ultraviolet light contained in the flame of the gas burner.

  In the ultraviolet detector 1, the first material of the cathode discharge part 21 has substantially no sensitivity to visible light. Thereby, it is possible to more reliably suppress photoelectron emission and discharge caused by light in the visible region, and detect light in a predetermined ultraviolet region with higher accuracy.

  Further, in the ultraviolet detector 1, the difference in thermal expansion coefficient between the second material used for the cathode support part 22 and the material of the container 10 is different between the first material used for the cathode discharge part 21 and the material of the container 10. It is smaller than the difference in thermal expansion coefficient. Thereby, it is possible to surely suppress the occurrence of changes in the first interval D1 and the second interval D2 due to a failure in the sealing portion 12 and to make the detection sensitivity more uniform, and to ensure the sealing portion 12. It is possible to prevent the discharge gas from escaping from, and to extend the life.

  Further, in the ultraviolet detector 1, the bent portion 33 is provided on the anode 30, and thereby the influence of the bent portion 33 on the cathode discharge portion 21 serving as a photoelectron emission region, for example, connection with the cathode support portion 22 by bending work. The influence on the part can be suppressed, and the detection sensitivity can be further uniformized.

  In the ultraviolet detector 1, the bent portion 33 faces the cathode discharge portion 21. For example, in the present embodiment, when the bent portion 33 provided on the anode 30 is provided at a position facing only the cathode support portion 22, the cathode support portion 22 and the anode discharge portion 31 generate discharge. Opposite at a first interval D1 that is easy. For this reason, there is a possibility that photoelectron emission and discharge due to light in the visible range may occur between the cathode support 22 and the anode discharge unit 31 that have low selectivity for light in the ultraviolet range. By causing at least a part of the bent portion 33 provided on the anode 30 to face the cathode discharge portion 21, the cathode support portion 22 is separated from the anode 30 by at least a distance greater than the first distance D 1. Can be detected, and light in a predetermined ultraviolet region can be detected with higher accuracy.

  In the ultraviolet detector 1, the cathode discharge portion 21 is a rod-shaped member made of the first material, and the cathode support portion 22 is a rod-shaped member made of the second material. The cathode discharge portion 21 and the cathode support portion 22 Are connected to each other. By configuring the cathode discharge portion 21 with a rod-shaped member made of the first material, for example, the surface of the cathode support portion 22 is configured by forming the first material in a film shape on a desired base material. In comparison, it is possible to suppress the possibility that the first material is peeled off due to the discharge, and to extend the life.

  In the ultraviolet detector 1, the width of the cathode discharge part 21 is larger than the width of the anode discharge part 31 when viewed from the direction in which the cathode discharge part 21 and the anode discharge part 31 face each other. Thereby, the detection sensitivity with respect to the light of a predetermined ultraviolet region can be made higher. Moreover, since the diameter of the cathode discharge part 21 is larger than the diameter of the cathode support part 22, a level | step difference arises in the connection part. Even at this level difference, the cathode support portion 22 is separated from the anode 30, so that the discharge at the cathode support portion 22 is suppressed and the detection sensitivity for light in a predetermined ultraviolet region can be further increased.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and may be modified without departing from the gist of the present invention or applied to other embodiments. .

  For example, like the ultraviolet detector 1A of the first modification shown in FIGS. 4 and 5, the cathode discharge part 21A may be formed in a flat plate shape. As shown in FIG. 5, in the ultraviolet detector 1 </ b> A as well, from the direction in which the cathode discharge portion 21 </ b> A and the anode discharge portion 31 face each other (the direction in which the cathode 20 and the anode 30 appear to overlap) as in the above embodiment. When viewed, the width of the cathode discharge part 21 </ b> A is larger than the width of the anode discharge part 31. Even with such an ultraviolet detector 1A, similarly to the above-described embodiment, it is possible to accurately detect light in a predetermined ultraviolet region even under visible light, and uniform detection sensitivity with a simple configuration. Can be planned. In particular, in this embodiment, it becomes easier to increase the width of the cathode discharge part 21A when viewed from the direction in which the cathode discharge part 21A and the anode discharge part 31 face each other. Furthermore, since the width of the cathode discharge part 21A can be increased with a small amount of material, the tip part of the electrode can be reduced in weight and the earthquake resistance can be improved. In addition, in FIG. 5, the container 10 is permeate | transmitted and the external shape of the container 10 is shown with the virtual line.

  Moreover, the cathode discharge part 21B may be contacting the sealing part 12 like the ultraviolet detector 1B of the 2nd modification shown by FIG. In the ultraviolet detector 1 </ b> B, the tip of the cathode discharge part 21 </ b> B on the sealing part 12 side is embedded in the sealing part 12. Therefore, the cathode support portion 22B does not have the cathode connection portion 24. Even with such an ultraviolet detector 1B, similarly to the above-described embodiment, it is possible to accurately detect light in a predetermined ultraviolet region even under visible light, and uniform detection sensitivity with a simple configuration. Can be planned. Further, since only the cathode discharge part 21B having high selectivity to ultraviolet light is exposed to the inside of the container 10, it is possible to more reliably suppress the occurrence of photoelectron emission and discharge due to visible light, It is possible to more accurately detect light in the ultraviolet region. Even when the tip of the cathode support portion 22B is embedded in the sealing portion 12 in this way, the majority of the portion sealed by the sealing portion 12 is the cathode sealed portion 25, so that the sealing portion 12 The cathode 20 can be sealed without any problem.

  Moreover, the bending part 23C may be provided in the cathode 20 like the ultraviolet detector 1C of the 3rd modification shown by FIG. In the ultraviolet detector 1 </ b> C, the cathode support portion 22 is provided with a bent portion 23 </ b> C. Further, the anode 30 is not provided with the bent portion 33, and the anode 30 is formed in a linear shape. The bent portion 23C faces the anode support portion 32. Even with such an ultraviolet detector 1C, similarly to the above-described embodiment, it is possible to accurately detect light in a predetermined ultraviolet region even under visible light, and uniform detection sensitivity with a simple configuration. Can be planned.

  Further, a bent portion 23D may be provided in the cathode discharge portion 21 as in the ultraviolet detector 1D of the fourth modified example shown in FIG. In the ultraviolet detector 1 </ b> D, the bent portion 23 </ b> D faces the anode discharge portion 31. Even with such an ultraviolet detector 1D, similarly to the above-described embodiment, it is possible to accurately detect light in a predetermined ultraviolet region even under visible light, and uniform detection sensitivity with a simple configuration. Can be planned. In particular, even if a discharge occurs in the middle of the bending portion 23D, the discharge is caused by light in a predetermined ultraviolet region, so that light in a predetermined ultraviolet region can be detected with higher accuracy.

  Moreover, in the said embodiment, while the cathode discharge part 21 is a rod-shaped member which consists of 1st materials, the cathode support part 22 is a rod-shaped member which consists of 2nd materials, and the cathode discharge part 21 and the cathode support part 22 mutually Although connected, the cathode discharge part 21 may be formed by forming the first material in a film shape so as to cover a part of the surface of the desired base material. For example, the base material which consists of the 2nd material of the length which match | combined the cathode discharge part 21 and the cathode support part 22 in the said embodiment is prepared, for example, 1st so that the desired one end side of the said base material may be covered. The film-like cathode discharge part 21 may be formed by performing a plating process using a material or the like.

  Moreover, in the said embodiment, although the bending part 33 was facing the area | region including the edge part by the side of the sealing part 12 among the cathode discharge parts 21, the sealing of the cathode discharge part 21 is carried out by the bending part 33. The distance from the anode 30 at the end portion on the side of the portion 12 (boundary portion with the cathode support portion 22) only needs to be equal to or greater than the first distance D1, and the bent portion 33 faces the intermediate portion of the cathode discharge portion 21. It may be. Moreover, the bending part 33 may be bent more steeply or may be bent more gently. Further, the cathode support portion 22 and the anode support portion 32 are not spaced apart at a constant distance by the second distance D2, but the spacing distance may change. Further, when viewed from the direction in which the cathode discharge portion 21 and the anode discharge portion 31 face each other, the width of the cathode discharge portion 21 may be substantially the same as the width of the anode discharge portion 31. May be smaller. The diameter of the cathode discharge part 21 may be the same as the diameter of the cathode support part 22 or may be smaller than the diameter of the cathode support part 22.

DESCRIPTION OF SYMBOLS 1,1A, 1B, 1C, 1D ... UV detector, 10 ... Container, 12 ... Sealing part, 20 ... Cathode, 21, 21A, 21B ... Cathode discharge part, 22, 22B ... Cathode support part, 23C, 23D ... Bending part, 30 ... anode, 31 ... anode discharge part, 32 ... anode support part, 33 ... bending part, D1 ... first interval, D2 ... second interval.

Claims (5)

A light-transmissive container filled with a discharge gas;
A rod-shaped cathode having a cathode discharge part disposed in the container, and a cathode support part penetrating the sealing part of the container;
An anode discharge part arranged in the container, and a rod-shaped anode having an anode support part penetrating the sealing part,
Only one of the cathode and the anode has the cathode discharge portion and the anode discharge portion facing each other at a first interval, and the cathode support portion and the anode support portion are larger than the first interval. Bending parts are provided so as to face each other at two intervals,
The first material constituting at least the surface of the cathode discharge part has a higher average sensitivity to light in a predetermined ultraviolet region than the average sensitivity to light in the visible region, and is a second material constituting at least the surface of the cathode support part. compared average sensitivity to light in the visible region and is rather low,
The bent portion is provided on the anode, and at least a part of the bent portion is opposed to the cathode discharge portion . A light-transmissive container filled with a discharge gas;
A rod-shaped cathode having a cathode discharge part disposed in the container, and a cathode support part penetrating the sealing part of the container;
An anode discharge part arranged in the container, and a rod-shaped anode having an anode support part penetrating the sealing part,
Only one of the cathode and the anode has the cathode discharge portion and the anode discharge portion facing each other at a first interval, and the cathode support portion and the anode support portion are larger than the first interval. Bending parts are provided so as to face each other at two intervals,
The first material constituting at least the surface of the cathode discharge part has a higher average sensitivity to light in a predetermined ultraviolet region than the average sensitivity to light in the visible region, and is a second material constituting at least the surface of the cathode support part. compared average sensitivity to light in the visible region and is rather low,
The bent part is an ultraviolet detector provided in the cathode discharge part . The ultraviolet detector according to claim 1 or 2 , wherein a difference in thermal expansion coefficient between the second material and the material of the container is smaller than a difference in thermal expansion coefficient between the first material and the material of the container. The said cathode discharge part is an ultraviolet detector as described in any one of Claims 1-3 which is a rod-shaped member which consists of said 1st material. The ultraviolet ray according to any one of claims 1 to 4 , wherein a width of the cathode discharge part is larger than a width of the anode discharge part when viewed from a direction in which the cathode discharge part and the anode discharge part are opposed to each other. Detector.

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