photoelectric tube

Abstract

The photoelectric tube includes a housing including a light-transmitting portion; an electron-emitting portion, held by a recessed portion provided in the housing and including a concave photoelectric element facing the light-transmitting portion within the housing; and an electron-capturing portion, disposed within the housing between the light-transmitting portion and the photoelectric element. At least a portion of the electron-capturing portion is located within a region inside the photoelectric element.

Description

Technical Field

[0001] The present invention relates to a photoelectric tube. Background Art

[0002] A phototube is known, which includes: a shell including a light-transmitting portion; an electron-emitting portion (photocathode) including a photoelectric surface arranged in the shell; and a mesh-shaped or point-shaped electron-capturing portion (anode) formed on the surface of the light-transmitting portion on the electron-emitting portion side (for example, see Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-067494

[0006] Patent Document 2: Japanese Patent Application Publication No. 2018-097925 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In the above-described phototube, if the electron-capturing sections are formed coarsely in a mesh or small in a dot-like manner to increase the probability that light incident on the light-transmitting section from the outside reaches the photoelectric surface, the probability that photoelectrons emitted from the photoelectric surface will be captured by the electron-capturing sections may decrease. On the other hand, if the electron-capturing sections are formed densely in a mesh or large in a dot-like manner to increase the probability that photoelectrons emitted from the photoelectric surface will be captured by the electron-capturing sections, the probability that light incident on the light-transmitting section from the outside reaches the photoelectric surface may decrease. Therefore, the above-described phototube structure cannot be said to have high light detection efficiency.

[0009] An object of the present invention is to provide a photoelectric tube capable of improving light detection efficiency.

[0010] Methods for solving problems

[0011] According to one aspect of the present invention, a photoelectric tube includes: a housing including a light-transmitting portion; an electron-emitting portion held by a recess provided in the housing and including a concave photoelectric surface within the housing facing the light-transmitting portion; and an electron-capturing portion disposed in the housing between the light-transmitting portion and the photoelectric surface, with at least a portion of the electron-capturing portion being located within a region inside the photoelectric surface.

[0012] In the above-described photoelectric tube, the electron-emitting portion includes a concave photoelectric surface within the housing, facing the light-transmitting portion. This facilitates light incident on the light-transmitting portion from the outside to reach the photoelectric surface. This increases the probability that light incident on the light-transmitting portion from the outside will reach the photoelectric surface. Furthermore, at least a portion of the electron-capturing portion is located within the region inside the concave photoelectric surface. This facilitates photoelectrons emitted from the photoelectric surface to reach the electron-capturing portion. This increases the probability that photoelectrons emitted from the photoelectric surface will be captured by the electron-capturing portion. As described above, the above-described photoelectric tube can improve light detection efficiency.

[0013] In one aspect of the photoelectric tube, the photoelectric surface may include a bottom surface and side surfaces, and the side surfaces may be curved such that the slope increases as they move away from the bottom surface. This makes it easier for photoelectrons emitted from the photoelectric surface to reach the electron-capturing unit. Consequently, the probability of photoelectrons emitted from the photoelectric surface being captured by the electron-capturing unit can be further increased.

[0014] In one aspect of the photoelectric tube of the present invention, the photoelectric surface may be circular when viewed from the light-transmitting portion. This allows photoelectrons emitted from the photoelectric surface to more easily reach the electron-capturing portion. This further increases the probability that photoelectrons emitted from the photoelectric surface will be captured by the electron-capturing portion.

[0015] In a photoelectric tube according to one aspect of the present invention, the electron capture portion can be a plate-shaped component configured to divide the area within the housing when viewed from the light-transmitting portion. Thus, light incident on the light-transmitting portion at a large angle of incidence is easily reflected by the pair of main surfaces of the electron capture portion and reaches the photoelectric surface. Therefore, the probability of light incident on the light-transmitting portion from the outside reaching the photoelectric surface can be further increased. Furthermore, the photoelectrons emitted from the photoelectric surface easily reach each of the pair of main surfaces of the electron capture portion. Therefore, the probability of photoelectrons emitted from the photoelectric surface being captured by the electron capture portion can be further increased.

[0016] In one aspect of the photoelectric tube of the present invention, the housing may further include a main body having a recessed portion, the light-transmitting portion may be attached to the main body so as to close an opening of the recessed portion, and the electron-emitting portion and the electron-capturing portion may be supported by the main body. This facilitates and reliably achieves a structure in which at least a portion of the electron-capturing portion is located within a region inside the recessed photoelectric element.

[0017] In one aspect of the photoelectric tube of the present invention, the electron emitting portion can be disposed on the inner surface of the recess, and the electron capturing portion can be mounted on the opening edge of the recess. This allows for an efficient layout in which at least a portion of the electron capturing portion is located within the region inside the recessed photoelectric surface.

[0018] The photoelectric tube according to one aspect of the present invention may further include a conductive portion electrically connected to the electron-capturing portion, with a portion of the conductive portion and a portion of the electron-emitting portion being exposed externally on a surface of the main body opposite the light-transmitting portion. Thus, external wiring can be electrically connected to a portion of the conductive portion and a portion of the electron-emitting portion, respectively, on the same surface (the surface of the main body opposite the light-transmitting portion) where light does not enter the light-transmitting portion and external wiring can be easily connected.

[0019] According to one aspect of the present invention, the photoelectric tube may further include a conductive layer configured to be arranged along the light-transmitting portion in a manner opposite to the photoelectric surface within the housing and to allow light to pass therethrough. Thus, for example, by assigning a negative potential to the electron-emitting portion based on the potential of the electron-capturing portion, and assigning a negative potential (or the same potential as the electron-emitting portion) to the conductive layer based on the potential of the electron-emitting portion, even if a portion of the photoelectrons emitted from the photoelectric surface travel toward the light-transmitting portion, the repulsive force generated between the portion of photoelectrons and the conductive layer will cause the portion of photoelectrons to rebound and easily reach the electron-capturing portion. Therefore, the probability of photoelectrons emitted from the photoelectric surface being captured by the electron-capturing portion can be further increased.

[0020] Effects of the Invention

[0021] According to the present invention, a photoelectric tube capable of improving light detection efficiency can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a top view of a photoelectric cell according to one embodiment.

[0023] Figure 2 It is along Figure 1 A cross-sectional view of a phototube along line II-II is shown.

[0024] Figure 3 It is along Figure 1 A cross-sectional view of a phototube along line III-III is shown.

[0025] Figure 4 yes Figure 1 An exploded perspective view of the phototube is shown.

[0026] Figure 5 This is a cross-sectional view of a photoelectric tube according to a first modification.

[0027] Figure 6 This is a cross-sectional view of a photoelectric tube according to a first modification.

[0028] Figure 7 This is a cross-sectional view of a photoelectric tube according to a second modified example.

[0029] Figure 8It is a perspective view of the electron capturing portion of the phototube according to the second modified example.

[0030] Figure 9 This is an exploded perspective view of a photoelectric tube according to a third modified example. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated descriptions are omitted.

[0032] like Figure 1 、 Figure 2 and Figure 3 As shown, phototube 1 includes a housing 2, an electron-emitting portion 3, an electron-capturing portion 4, a conductive layer 5, a pair of first conductive portions (conductive portions) 6, and a second conductive portion 7. In phototube 1, electron-emitting portion 3 functions as a photocathode, and electron-capturing portion 4 functions as an anode. The light detected by phototube 1 is, for example, ultraviolet light.

[0033] The housing 2 includes a main body 21 and a light-transmitting portion 22. The main body 21 has a recess 23 open on one side in the Z-axis direction. In the main body 21, the recess 23 is defined by a bottom wall 24 and side walls 25. A groove 26 is provided between the recess 23 and the side walls 25, substantially surrounding the recess 23. This improves the withstand voltage characteristics between components assigned different potentials. The main body 21 is, for example, a plate-shaped member (thickness: several millimeters) that is square (side length: approximately 10 mm) when viewed in the Z-axis direction and is formed from an insulating material (such as Kovar glass). The light-transmitting portion 22 is attached to the main body 21 so as to close the opening of the recess 23. The light-transmitting portion 22 transmits light to be detected by the phototube 1. The light-transmitting portion 22 is, for example, a plate-shaped member (thickness: less than 1 mm) that is square (side length: approximately 10 mm) when viewed in the Z-axis direction and is formed from an insulating material (such as quartz glass). In this embodiment, the area inside the housing 2 is maintained at a high vacuum.

[0034] like Figure 4As shown, a base layer 11 is arranged in a frame shape on the end face 25a of the side wall 25 of the main body 21 (the end face on the light-transmitting portion 22 side). On the surface 22a of the light-transmitting portion 22 on the electron-emitting portion 3 side, a base layer 12 is arranged in a frame shape along the outer edge of the light-transmitting portion 22. A bonding layer 13 is arranged in a frame shape between the base layer 11 and the base layer 12. The light-transmitting portion 22 is airtightly bonded to the side wall 25 of the main body 21 by the base layer 11, the base layer 12, and the bonding layer 13. The base layer 11 and the base layer 12 are metal layers (so-called metallization layers) for improving the adhesion between the bonding layer 13 and the main body 21 and the adhesion strength between the bonding layer 13 and the light-transmitting portion 22, and are formed, for example, of Cr / Ni / Cu or Ti / Pt / Au. The bonding layer 13 is formed of a conductive material (for example, a bonding metal such as In or a solder such as AuSn).

[0035] like Figure 1 、 Figure 2 and Figure 3 As shown, the electron emitting portion 3 includes an electrode body 31 and a photoelectric element 32. The electron emitting portion 3 is held by the recess 23 of the main body 21 of the housing 2, while the photoelectric element 32 is disposed within the housing 2. In this embodiment, the electron emitting portion 3 is disposed on the inner surface 23a of the recess 23 of the main body 21. A portion of the electron emitting portion 3 is exposed to the outside of the main body 21a via an opening 21c formed in the surface 21a of the main body 21 opposite the light-transmitting portion 22. More specifically, the bowl-shaped electrode body 31 is fixed to the inner surface 23a of the recess 23, for example, by welding or bonding using a bonding member. The bottom 31a of the electrode body 31, which protrudes in a convex shape, is exposed to the outside of the main body 21a via the opening 21c of the main body 21. The photoelectric element 32 is a photoelectric conversion film formed along the inner surface of the bowl-shaped electrode body 31. The electrode body 31 is formed of a conductive material (for example, a metal material such as Kovar), and the photocathode 32 is formed of, for example, CsTe.

[0036] The photoelectric surface 32 is a concave surface facing the light-transmitting portion 22 side in the housing 2. That is, the photoelectric surface 32 is recessed in the housing 2 toward the side opposite to the light-transmitting portion 22 (that is, the side away from the light-transmitting portion 22). The photoelectric surface 32 includes a bottom surface 32a and a side surface 32b. The bottom surface 32a is a flat surface perpendicular to the Z-axis direction. The side surface 32b is curved in such a manner that the inclination increases as it moves away from the bottom surface 32a (that is, the closer it is to the light-transmitting portion 22). The side surface 32b is connected to the bottom surface 32a in a continuously inclined manner. The bottom surface 32a is circular when viewed from the light-transmitting portion 22 side, and the side surface 32b is annular when viewed from the light-transmitting portion 22 side. That is, the photoelectric surface 32 is circular when viewed from the light-transmitting portion 22 side.

[0037] The electron capturing portion 4 is arranged between the light transmitting portion 22 and the photoelectric element 32 in the housing 2. The electron capturing portion 4 is a plate-shaped component (thickness: about 0.4 mm) formed of a conductive material (for example, a metal material such as Kovar), and is arranged to divide the area in the housing 2 when viewed from the light transmitting portion 22 side. That is, the electron capturing portion 4 is arranged in such a manner that a pair of main surfaces 4a of the electron capturing portion 4 are parallel to the Z-axis direction. When viewed from the Y-axis direction (when viewed in a manner opposite to the main plane of the plate-shaped component), the edge of each main surface 4a is roughly elliptical (including a shape of a smooth arc portion and a straight line portion) extending along the inner surface 23a of the recess 23 and opposite to the inner surface 23a of the recess 23. The electron capturing portion 4 is supported by the main body 21 of the housing 2. In this embodiment, the electron capturing portion 4 is mounted on the opening edge 23b of the recess 23 of the main body 21. More specifically, a pair of end portions 4 b of the electron capturing portion 4 that protrude outward in the X-axis direction are arranged at portions of the opening edge 23 b that face each other in the X-axis direction.

[0038] A portion 41 of the electron capturing portion 4 is located in the region 33 on the inner side of the concave photoelectric surface 32. That is, the portion 41 of the electron capturing portion 4 is located on the side opposite to the light-transmitting portion 22 relative to the opening edge 32c of the concave photoelectric surface 32. A portion 42 of the electron capturing portion 4 other than the portion 41 is located in the region outside the concave photoelectric surface 32 (i.e., outside the region 33). That is, the portion 42 of the electron capturing portion 4 is located on the light-transmitting portion 22 side relative to the opening edge 32c of the concave photoelectric surface 32. The side surface 41a of the portion 41 of the electron capturing portion 4 (the side surface between the pair of main surfaces 4a and the side surface opposite to the photoelectric surface 32) extends along the photoelectric surface 32 when viewed from the Y-axis direction. The electron capturing portion 4 is separated from the photoelectric surface 32 by a predetermined distance in the housing 2 so that the distance between the side surface 41a and the photoelectric surface 32 is approximately uniform, and is not electrically connected to the photoelectric surface 32.

[0039] The conductive layer 5 is arranged at a position closer to the light-transmitting portion 22 than the electron capturing portion 4 in a manner opposite to the photoelectric surface 32 in the housing 2. In the present embodiment, the conductive layer 5 is arranged along the light-transmitting portion 22 in a manner opposite to the photoelectric surface 32 in the housing 2. The conductive layer 5 is separated from the electron capturing portion 4 at a predetermined distance in the housing 2 and is not electrically connected to the electron capturing portion 4. In the present embodiment, the conductive layer 5 is arranged on the surface 22a of the light-transmitting portion 22. That is, the conductive layer 5 is supported by the light-transmitting portion 22. The conductive layer 5 is configured to allow light to be detected by the phototube 1 to pass through. In the present embodiment, the conductive layer 5 is formed into a film-like shape with a thickness set according to the wavelength by a material selected according to the wavelength of the light to be detected by the phototube 1. The material of the conductive layer 5 is, for example, Ni, and the thickness of the conductive layer 5 is, for example, on the order of several nm.

[0040] like Figure 1 and Figure 4 As shown, the conductive layer 5 is located on the inner side of the base layer 12 on the surface 22a of the light-transmitting portion 22. As an example, the conductive layer 5 is square when viewed from the Z-axis direction and is located on the inner side of the square frame-shaped base layer 12. The corner 5a of the conductive layer 5 overlaps with the protrusion 12a of the base layer 12, and overlaps with the protrusion 11a of the base layer 11 via the bonding layer 13. Thus, the conductive layer 5, the base layer 11, the base layer 12 and the bonding layer 13 are electrically connected to each other. The corner 5a is one of a pair of corners of the conductive layer 5 that are opposite in the Y-axis direction. The protrusion 11a is a portion that protrudes inward from one of a pair of corners of the base layer 11 that are opposite in the Y-axis direction, and the protrusion 12a is a portion that protrudes inward from one of a pair of corners of the base layer 12 that are opposite in the Y-axis direction.

[0041] like Figure 1 and Figure 2 As shown, a pair of first conductive portions 6 are electrically connected to the electron capturing portion 4, with a portion of each first conductive portion 6 being exposed to the outside on the surface 21a of the main body 21. More specifically, an end 6a of each first conductive portion 6 on the light-transmitting portion 22 side is electrically connected to an end 4b of a portion 42 provided in the electron capturing portion 4, and an end 6b of each first conductive portion 6 on the opposite side of the end 6a is exposed to the outside on the surface 21a of the main body 21. Each first conductive portion 6 is electrically connected to the electron capturing portion 4 outside the region 33 inside the concave photoelectric cathode 32. Therefore, the electron capturing portion 4 and the pair of first conductive portions 6 are separated from the photoelectric cathode 32, which is assigned a different potential than the electron capturing portion 4 and the pair of first conductive portions 6, thereby improving the withstand voltage characteristics between components assigned different potentials. As an example, each first conductive portion 6 extends in the Z-axis direction at a pair of corners of the side wall 25 of the main body 21 that are opposite in the X-axis direction. The pair of first conductive portions 6 are formed integrally with the electron capturing portion 4 using a conductive material (eg, Kovar).

[0042] like Figure 1 and Figure 3 As shown, the second conductive portion 7 is electrically connected to the conductive layer 5, and a portion of the second conductive portion 7 is exposed to the outside on the surface 21a of the main body 21. More specifically, the end portion 7a of the second conductive portion 7 on the light-transmitting portion 22 side is connected to the conductive layer 5 via the protrusion 11a of the base layer 11, the protrusion 12a of the base layer 12, and the bonding layer 13 (see Figure 4 ) and is electrically connected to the corner portion 5a of the conductive layer 5. The end portion 7b of the second conductive portion 7 opposite the end portion 7a is exposed to the outside on the surface 21a of the main body 21. As an example, the second conductive portion 7 extends in the Z-axis direction at one of a pair of corners of the side wall 25 of the main body 21 that oppose each other in the Y-axis direction. The second conductive portion 7 is formed of a conductive material (e.g., Kovar).

[0043] In the photoelectric tube 1 constructed as described above, for example, a negative potential is assigned to the electron emitting portion 3 based on the potential of the electron capturing portion 4 (ground potential), and a negative potential (or a potential equal to the potential of the electron emitting portion 3) is assigned to the conductive layer 5 based on the potential of the electron emitting portion 3. In this state, if light incident on the light-transmitting portion 22 from the outside passes through the light-transmitting portion 22 and the conductive layer 5 and reaches the photoelectric element 32, photoelectrons are emitted from the photoelectric element 32 due to the photoelectron emission effect. Of the photoelectrons emitted from the photoelectric element 32, those traveling toward the electron capturing portion 4 are attracted to the electron capturing portion 4 and reach the electron capturing portion 4. Of the photoelectrons emitted from the photoelectric element 32, those traveling toward the light-transmitting portion 22 are repelled by the repulsive force generated between the photoelectrons and the conductive layer 5 and reach the electron capturing portion 4. By detecting the photoelectrons (current) that reach the electron capturing portion 4 in this manner, light can be detected. Furthermore, from the perspective of simplifying the power supply to the photoelectric tube 1 by using the same voltage value as much as possible, it is preferable to have the electron emitting portion 3 and the conductive layer 5 at the same potential.

[0044] As described above, in the photoelectric tube 1, the electron emitting portion 3 includes a concave photoelectric surface 32 facing the light-transmitting portion 22 in the housing 2. As a result, the area of ​​the photoelectric surface 32 is increased, for example, compared to a case where the photoelectric surface 32 is flat, and light incident on the light-transmitting portion 22 from the outside can easily reach the photoelectric surface 32. Therefore, the probability that light incident on the light-transmitting portion 22 from the outside reaches the photoelectric surface 32 can be increased. In addition, a portion 41 of the electron capturing portion 4 is located in the region 33 on the inner side of the concave photoelectric surface 32. As a result, the photoelectrons emitted from the photoelectric surface 32 can easily reach the electron capturing portion 4. Therefore, the probability that the photoelectrons emitted from the photoelectric surface 32 are captured by the electron capturing portion 4 can be increased. As described above, according to the photoelectric tube 1, the light detection efficiency can be improved.

[0045] In the photoelectric tube 1, the side surface 32b of the photoelectric surface 32 is curved so that its slope increases as it moves away from the bottom surface 32a of the photoelectric surface 32. This makes it easier for photoelectrons emitted from the photoelectric surface 32 (particularly photoelectrons emitted from the side surface 32b of the photoelectric surface 32) to reach the electron capturing unit 4. Consequently, the probability of photoelectrons emitted from the photoelectric surface 32 being captured by the electron capturing unit 4 can be further increased.

[0046] In the photoelectric tube 1, the photoelectric surface 32 has a circular shape when viewed from the light-transmitting portion 22. This allows photoelectrons emitted from the photoelectric surface 32 (particularly photoelectrons emitted from the side surface 32b of the photoelectric surface 32) to more easily reach the electron-capturing portion 4. Consequently, the probability of photoelectrons emitted from the photoelectric surface 32 being captured by the electron-capturing portion 4 can be further increased.

[0047] In the photoelectric tube 1, the electron capturing portion 4 is a plate-shaped component that is arranged so as to divide the area within the housing 2 when viewed from the light-transmitting portion 22. As a result, light incident on the light-transmitting portion 22 at a large incident angle is easily reflected by each of the pair of main surfaces 4a in the electron capturing portion 4 and reaches the photoelectric surface 32. Therefore, the probability that light incident on the light-transmitting portion 22 from the outside reaches the photoelectric surface 32 can be further increased. Furthermore, the photoelectrons emitted from the photoelectric surface 32 easily reach each of the pair of main surfaces 4a in the electron capturing portion 4. Therefore, the probability that the photoelectrons emitted from the photoelectric surface 32 are captured by the electron capturing portion 4 can be further increased.

[0048] In the photoelectric tube 1, the light-transmitting portion 22 is attached to the main body 21 so as to close the opening of the recessed portion 23, and the electron-emitting portion 3 and the electron-capturing portion 4 are supported by the main body 21. This makes it possible to easily and reliably achieve a structure in which a portion 41 of the electron-capturing portion 4 is located within the region 33 inside the recessed photoelectric surface 32.

[0049] In the photoelectric tube 1, the electron-emitting portion 3 is disposed on the inner surface 23a of the recessed portion 23 of the main body 21, and the electron-capturing portion 4 is mounted on the opening edge 23b of the recessed portion 23 of the main body 21. This allows for an efficient layout in which a portion 41 of the electron-capturing portion 4 is located within the region 33 inside the recessed photoelectric surface 32. Furthermore, the electron-emitting portion 3 and the electron-capturing portion 4 can be stably held, resulting in a highly shock-resistant structure.

[0050] In the phototube 1, a portion of each first conductive portion 6 electrically connected to the electron capturing portion 4, a portion of the second conductive portion 7 electrically connected to the conductive layer 5, and a portion of the electron emitting portion 3 are exposed to the outside on the surface 21a of the main body 21. This allows external wiring to be electrically connected to a portion of each first conductive portion 6, a portion of the second conductive portion 7, and a portion of the electron emitting portion 3 on the same surface (the surface 21a of the main body 21), which does not obstruct the incidence of light on the light-transmitting portion 22 and facilitates connection of external wiring. Furthermore, a desired potential can be applied to each of the electron emitting portion 3, the electron capturing portion 4, and the conductive layer 5.

[0051] In the photoelectric tube 1, a conductive layer 5 configured to allow light to pass therethrough is disposed within the housing 2 along the light-transmitting portion 22, facing the photoelectric element 32. Thus, for example, by assigning a negative potential to the electron-emitting portion 3 relative to the potential of the electron-capturing portion 4 (ground potential), and assigning a negative potential to the conductive layer 5 relative to the potential of the electron-capturing portion 3 (or a potential equal to that of the electron-capturing portion 3), even if some of the photoelectrons emitted from the photoelectric element 32 travel toward the light-transmitting portion 22, the repulsive force generated between the photoelectrons and the conductive layer 5 causes them to rebound and more easily reach the electron-capturing portion 4. Consequently, the probability of photoelectrons emitted from the photoelectric element 32 being captured by the electron-capturing portion 4 can be further increased.

[0052] As an example, the phototube 1 is manufactured as follows. First, the electron emitting portion 3, the integrally formed electron capturing portion 4, the pair of first conductive portions 6, and the second conductive portion 7 (hereinafter referred to as the "electron emitting portion 3, etc.") are placed on a jig. Next, a Kovar glass plate is melted and resolidified on the jig with the electron emitting portion 3, etc., to unitize the electron emitting portion 3, etc. with the main body 21. Next, the surface 21a of the main body 21 is polished so that a portion of each of the first conductive portion 6, a portion of the second conductive portion 7, and a portion of the electron emitting portion 3 are exposed to the outside on the surface 21a of the main body 21. Next, the base layer 11 is formed on the end surface 25a of the side wall 25 of the main body 21. Meanwhile, the conductive layer 5 and the base layer 12 are formed on the surface 22a of the light-transmitting portion 22. Next, in a high vacuum chamber, the base layer 11 formed on the main body 21 and the base layer 12 formed on the light-transmitting portion 22 are bonded via the bonding layer 13, thereby completing the phototube 1.

[0053] Each of the above steps is performed on a wafer containing multiple phototubes 1, each of which has a two-dimensional array of structures. Finally, the individual phototubes 1 are cut out. This reduces the number of assembly steps, thereby reducing manufacturing costs and enabling mass production of miniaturized phototubes 1. In the phototubes 1, since the electron emitter 3 and other components are unitized with the main body 21, the positional accuracy of the electron emitter 3 and other components is improved, preventing displacement of the electron emitter 3 and other components due to vibration and shock.

[0054] The present invention is not limited to the above-mentioned embodiments. Figure 5 and Figure 6 As shown, in the photoelectric tube 1, a portion of the electron emitting portion 3 is not exposed to the outside on the surface 21a of the main body 21, and the electron emitting portion 3 and the conductive layer 5 can also be electrically connected through the wiring 8. Figure 5 and Figure 6 In the photoelectric tube 1 shown, the wiring 8 is formed on the inclined surface 21b of the main body 21. The inclined surface 21b extends from the opening edge 23b of the recess 23 to the end surface 25a of the side wall 25. Figure 5 and Figure 6 In the phototube 1 shown, external wiring can be electrically connected to a portion of each of the first conductive portion 6 and the second conductive portion 7 on the same surface (surface 21a of the main body 21) where light does not interfere with the incidence of light on the light-transmitting portion 22 and where external wiring can be easily connected. For example, a negative potential can be applied to the electron-emitting portion 3 and the conductive layer 5 with reference to the potential of the electron-capturing portion 4 (ground potential). Furthermore, the structure of the conductive portion for electrically connecting external wiring can be simplified.

[0055] like Figure 5 and Figure 6 As shown, in the photoelectric tube 1 in which the electron emitting portion 3 and the conductive layer 5 are electrically connected via the wiring 8, the second conductive portion 7 may not be provided, and a portion of the electron emitting portion 3 may be exposed to the outside on the surface 21a of the main body 21. In this case, by electrically connecting external wiring to a portion of each of the first conductive portions 6 and a portion of the electron emitting portion 3 exposed to the outside on the surface 21a of the main body 21, for example, a negative potential can be applied to the electron emitting portion 3 and the conductive layer 5 with respect to the potential of the electron capturing portion 4 (ground potential) as a reference.

[0056] The electron capture unit 4 is not limited to a plate-shaped component. As an example, Figure 7 and Figure 8 As shown in FIG. 4 , the electron capturing portion 4 may also be a bowl-shaped component having a plurality of light passage openings 4 c. Figure 7 In the photoelectric tube 1 shown, a portion 41 including the bottom of the electron capturing portion 4 is located in a region 33 inside the photoelectric surface 32. Figure 7 In the photoelectric tube 1 shown, light passing through the light-transmitting portion 22 and the conductive layer 5 reaches the photoelectric surface 32 through the plurality of light-passing openings 4c. Figure 7 In FIG. 1 , the light passage opening 4 c formed in the portion other than the cross-sectional portion of the electron capturing portion 4 is omitted from illustration.

[0057] The conductive layer 5 is not limited to being formed in a film shape. As an example, Figure 9 As shown, the conductive layer 5 may be formed in a mesh shape. That is, the conductive layer 5 only needs to be configured to allow light to pass therethrough.

[0058] In the above embodiment and all variations, the region within the housing 2 may be a region enclosed in a discharge gas such as neon or hydrogen. In the above embodiment and all variations, a single first conductive portion 6 may be electrically connected to the electron capturing portion 4 instead of a pair of first conductive portions 6.

[0059] In the above-described embodiment and all of its variations, the photoelectrode 32 need only be a concave surface facing the light-transmitting portion 22 within the housing 2. For example, it need not include a side surface 32b that is curved so that its inclination increases as it moves away from the bottom surface 32a. In the above-described embodiment and all of its variations, the electron capturing portion 4 need only have at least a portion 41 located within the region 33 inside the concave photoelectrode 32. For example, the entire electron capturing portion 4 may be located within the region 33. In the above-described embodiment and all of its variations, the phototube 1 need not include a conductive layer 5. In the above-described embodiment and all of its variations, the first conductive portion 6 may be directly connected to the electron capturing portion 4 or indirectly connected to the electron capturing portion 4 (i.e., via another conductive component). In other words, the first conductive portion 6 and the electron capturing portion 4 may be electrically connected. In the above-described embodiment and all of its variations, the second conductive portion 7 may be directly connected to the conductive layer 5 or indirectly connected to the conductive layer 5 (i.e., via another conductive component). In other words, the second conductive portion 7 and the conductive layer 5 may be electrically connected.

[0060] Description of Reference Numerals

[0061] 1…Photocell

[0062] 2…housing

[0063] 3…Electron emission unit

[0064] 4…Electron capture unit

[0065] 5…conductive layer

[0066] 6…1st conductive portion (conductive portion)

[0067] 21…Main body

[0068] 21a…Surface

[0069] 22…Light transmission part

[0070] 23…concave

[0071] 23a…Inner surface

[0072] 23b…opening edge

[0073] 32…Photoelectric surface

[0074] 32a… bottom

[0075] 32b…side

[0076] 33…area

[0077] 41…part.

Claims

1. A photoelectric tube comprising: a housing including a light-transmitting portion; an electron emitting portion held by a recess provided in the housing and including a concave photoelectric surface facing the light transmitting portion in the housing; and an electron capturing portion disposed between the light transmitting portion and the photoelectric element in the housing; At least a portion of the electron capturing portion is located in a region inside the photoelectric element.

2. The photoelectric tube according to claim 1, wherein The photoelectric surface comprises a bottom surface and a side surface, The side surface is curved such that the slope increases as the side surface becomes farther away from the bottom surface.

3. The photoelectric tube according to claim 1, wherein The photoelectric surface has a circular shape when viewed from the light transmitting portion.

4. The photoelectric tube according to claim 2, wherein The photoelectric surface has a circular shape when viewed from the light transmitting portion.

5. The photoelectric tube according to claim 1, wherein The electron capturing portion is a plate-shaped member, and is arranged so as to divide the region within the housing when viewed from the light transmitting portion side.

6. The photoelectric tube according to claim 2, wherein The electron capturing portion is a plate-shaped member, and is arranged so as to divide the region within the housing when viewed from the light transmitting portion side.

7. The photoelectric tube according to claim 3, wherein The electron capturing portion is a plate-shaped member, and is arranged so as to divide the region within the housing when viewed from the light transmitting portion side.

8. The photoelectric tube according to claim 4, wherein The electron capturing portion is a plate-shaped member, and is arranged so as to divide the region within the housing when viewed from the light transmitting portion side.

9. The photoelectric tube according to any one of claims 1 to 8, wherein The housing further includes a main body having the recessed portion. The light transmitting portion is mounted on the main body in a manner to close the opening of the recessed portion. The electron emitting portion and the electron capturing portion are supported by the main body portion.

10. The photoelectric tube according to claim 9, wherein The electron emission portion is arranged on the inner surface of the recessed portion. The electron capturing portion is provided on an opening edge of the recess.

11. The photoelectric tube according to claim 9, wherein The photoelectric tube further includes a conductive portion electrically connected to the electron capturing portion. A portion of the conductive portion and a portion of the electron emitting portion are exposed to the outside on a surface of the main body portion on the side opposite to the light transmitting portion.

12. The photoelectric tube according to claim 10, wherein The photoelectric tube further includes a conductive portion electrically connected to the electron capturing portion. A portion of the conductive portion and a portion of the electron emitting portion are exposed to the outside on a surface of the main body portion on the side opposite to the light transmitting portion.

13. The photoelectric tube according to any one of claims 1 to 8, wherein: The photoelectric tube further includes a conductive layer, and the conductive layer is arranged along the light-transmitting portion in the housing so as to face the photoelectric surface and to allow light to pass therethrough.

14. The photoelectric tube according to claim 9, wherein The photoelectric tube further includes a conductive layer, and the conductive layer is arranged along the light-transmitting portion in the housing so as to face the photoelectric surface and to allow light to pass therethrough.

15. The photoelectric tube according to any one of claims 10 to 12, wherein: The photoelectric tube further includes a conductive layer, and the conductive layer is arranged along the light-transmitting portion in the housing so as to face the photoelectric surface and to allow light to pass therethrough.

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