TW201340511A - Electron-beam-excited uv emission device - Google Patents

Abstract

Provided is an electron-beam-excited UV emission device in which: an electron beam is efficiently beamed onto a semiconductor light-emitting element; high-output UV light can be emitted; the size can be made more compact; and the semiconductor light-emitting element can be efficiently cooled. This invention is characterized in being provided with: a vacuum container having a UV extraction window; a highly thermally conductive support member provided in the vacuum container, the support member having a support surface inclined with respect to the UV extraction window; the semiconductor light-emitting element disposed on the support surface of the support member; and an electron beam source for supplying an electron beam to the semiconductor light-emitting element.

Description

Electron beam excitation type ultraviolet radiation device

The present invention relates to an electron beam excitation type ultraviolet radiation device including an electron beam source and a semiconductor light emitting element that emits ultraviolet rays by an electron beam emitted from the electron beam source.

An electron beam excitation type ultraviolet radiation device that emits ultraviolet light from a semiconductor light emitting element by irradiation with an electron beam is expected to be a light source that emits ultraviolet light that is small and emits high output.

As such an electron beam excitation type ultraviolet radiation device, (1) a laser container having a UV transmission window, and a laser structure having a semiconductor light emitting element disposed on an inner surface of the light transmission window of the vacuum container are disposed. The electron beam source is formed on the inner surface of the bottom wall opposite to the light transmission window of the vacuum container (see Patent Document 1), and (2) the electron beam is incident on one side of the semiconductor light-emitting element from the oblique direction. The light is emitted from one side of the semiconductor light-emitting element that is incident on the electron beam, and the light is emitted from the light-transmitting window disposed on one surface of the semiconductor light-emitting element toward the outside (see Patent Document 2).

However, in the electron beam excitation type ultraviolet radiation device of the above (1), one surface of the semiconductor light emitting element is utilized as light emission. Since the other surface is used as the incident surface of the electron beam, the semiconductor light emitting element cannot be cooled from one of the large areas and the other surface. Therefore, it is difficult to efficiently cool the semiconductor light emitting element. As a result, since the semiconductor light-emitting element generates heat at a relatively high temperature, the light-emitting efficiency of the semiconductor light-emitting element is lowered, and high-output light cannot be emitted, and there is a problem that the semiconductor light-emitting element causes an early failure due to heat generation.

Further, in the electron beam excitation type ultraviolet radiation device of the above (2), since the semiconductor light emitting element can be cooled from the rear surface, the light emission efficiency of the semiconductor light emitting element can be maintained without lowering the light output, but it is necessary to be in the semiconductor. Since the electron gun is disposed obliquely to the front side of one of the light-emitting elements, it is difficult to further reduce the size.

In order to solve such a problem, it is considered that an electron beam source from the electron beam source is incident on one surface of the semiconductor light-emitting element by arranging an electron beam source at a peripheral position of the semiconductor light-emitting element, and radiation is emitted from one surface of the semiconductor light-emitting element. The construction of light. According to this configuration, the semiconductor light emitting element can be cooled from the other surface of the semiconductor light emitting element, and the electron beam source is disposed at the peripheral position of the semiconductor light emitting element, so that the size can be reduced.

However, in the electron beam excitation type ultraviolet radiation device having such a configuration, since the angle of incidence of the electron beam from the electron beam source on one surface of the semiconductor light emitting element is extremely small, the electron beam cannot sufficiently enter the active layer of the semiconductor light emitting element. Internally, it was found that the luminous efficiency was extremely low, and it was difficult to obtain a high-output ultraviolet ray.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3667188

[Patent Document 2] Japanese Laid-Open Patent Publication No. 09-214027

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electron beam that can be efficiently injected into a semiconductor light-emitting element, emit high-output ultraviolet rays, can be miniaturized, and can efficiently cool the semiconductor light-emitting element. Electron beam excited ultraviolet radiation device.

An electron beam excitation type ultraviolet radiation device according to the present invention is characterized by comprising: a vacuum container having an ultraviolet ray take-out window; and a high thermal conductivity supporting member provided in the vacuum container and having a support surface inclined to the ultraviolet ray take-out window The semiconductor light emitting element is disposed on the support surface of the support member, and the electron beam source supplies the electron beam to the semiconductor light emitting element.

In the electron beam excitation type ultraviolet radiation device of the present invention, the support member has a plurality of the support faces, and the semiconductor light-emitting elements are preferably arranged close to each other on each of the support faces.

In such an electron beam excitation type ultraviolet radiation device, it is preferable to provide the electron beam source in accordance with each of the semiconductor light emitting elements.

Further, in the electron beam excitation type ultraviolet radiation device of the present invention, it is preferable to provide an electron beam focusing electrode for focusing the electron beam from the electron beam source toward the semiconductor light emitting element.

According to the electron beam excitation type ultraviolet radiation device of the present invention, since the support surface of the semiconductor light emitting element is inclined with respect to the ultraviolet light extraction window, even in the case where the electron beam source is disposed at the peripheral position of the semiconductor light emitting element, the semiconductor light is emitted. The incident angle of the light from the electron beam source on one of the elements is also sufficiently large, so that the electron beam can be efficiently incident on the semiconductor light emitting element, and the high-output ultraviolet light can be emitted.

Moreover, since the electron beam source can be disposed at the peripheral position of the semiconductor light emitting element, the size of the device can be reduced.

Further, since the supporting member for arranging the semiconductor light emitting element has high thermal conductivity, the semiconductor light emitting element can be efficiently cooled by the supporting member. Therefore, the luminous efficiency of the semiconductor light emitting element is not lowered, and high-output ultraviolet rays can be maintained.

Further, according to the structure in which the support member has a plurality of support faces, and the support surface semiconductor light-emitting elements are arranged close to each other, the ultraviolet radiation area is large, and the high-output ultraviolet rays can be further maintained.

10‧‧‧Vacuum container

11‧‧‧ Container base

12‧‧‧ bottom wall

13a, 13b‧‧‧ side wall

15‧‧‧UV removal window

16‧‧‧Support components

17‧‧‧Support surface

20‧‧‧Semiconductor light-emitting elements

20a‧‧‧ surface

21‧‧‧Substrate

22‧‧‧ Buffer layer

25‧‧‧Active layer

26‧‧‧Quantum wells

27‧‧‧Baffle layer

30‧‧‧Electronic beam source

31‧‧‧Support substrate

32‧‧‧Electron beam release department

33‧‧‧Base

35‧‧‧Extraction electrode

36‧‧‧Electrode holding member

37‧‧‧ Keeping components

40‧‧‧electron beam focusing electrode

41‧‧‧ Keeping components

45‧‧‧ Charge residue prevention component

Fig. 1 is an explanatory view showing a structure of an example of an electron beam excitation type ultraviolet radiation device of the present invention, wherein (a) is a side sectional view and (b) is a plan view showing a state in which an ultraviolet removal window is removed.

Fig. 2 is a cross-sectional view for explaining the structure of a semiconductor light emitting element of the electron beam excitation type ultraviolet radiation device shown in Fig. 1.

Fig. 3 is a cross-sectional view for explaining the structure of an electron beam source of the electron beam excitation type ultraviolet radiation device shown in Fig. 1.

Fig. 4 is an explanatory view showing a structure of another essential part of an electron beam excitation type ultraviolet radiation device of the present invention, wherein (a) is a plan view and (b) is a side sectional view.

Fig. 5 is an explanatory view showing another essential part structure of an electron beam excitation type ultraviolet radiation device of the present invention, wherein (a) is a plan view and (b) is a side sectional view.

1 is an explanatory view showing an example of a structure of an electron beam excitation type ultraviolet radiation device of the present invention, wherein (a) is a side sectional view and (b) is a plan view showing a state in which an ultraviolet removal window is removed.

The electron beam-excited ultraviolet radiation device has a vacuum container 10 having a rectangular shape in a sealed state in a state of a negative pressure, and the vacuum container 10 is provided by one side (the upper side in FIG. 1(a)). The open container base 11 and the opening disposed in the container base 11 are hermetically sealed A rectangular plate-shaped ultraviolet ray take-up window 15 connected to the container base 11 is formed.

In the vacuum vessel 10, from the bottom wall 12 of the container base 11 toward the ultraviolet ray take-up window 15, a columnar high thermal conductivity supporting member 16 extending in a direction perpendicular to the ultraviolet ray take-up window 15 is fixed at the base end. The bottom wall 12 of the container body 11 is disposed in a state of being separated from the ultraviolet ray take-up window 15. At the front end of the support member 16, two semicircular support faces 17 which are inclined to the ultraviolet ray take-up window 15 are formed.

One of the semiconductor light-emitting elements 20 each having a rectangular plate shape on the two support faces 17 of the support member 16 is disposed close to each other in a posture in which the surface 20a is inclined with respect to the ultraviolet ray take-up window 15.

In response to the semiconductor light-emitting device 20, an electron beam source 30 formed by the electron beam emitting portion 32 is formed on the surface of the support substrate 31, and the electron beam emitting portion 32 faces the surface 20a of the semiconductor light-emitting device 20, and is disposed in the posture of the electron beam emitting portion 32. The peripheral positions of the semiconductor light emitting element 20 are specifically the positions between the semiconductor light emitting element 20 and the container base 11 which are close to the side walls 13a and 13b of the semiconductor light emitting element 20. In the illustrated example, the electron beam source 30 is disposed so as to face the semiconductor light emitting element 20 such that the surface of the electron beam emitting portion 32 is perpendicular to the ultraviolet light extraction window 15. The electron beam source 30 is fixed to the bottom wall 12 of the container base 11 through the holding member 37.

Further, between the semiconductor light emitting element 20 and the electron beam source 30, an electron beam from the electron beam source 30 is disposed toward the semiconductor light emitting element 20 The focused annular electron beam focusing electrode 40. The electron beam focusing electrode 40 is transmitted through the holding member 41 and fixed to the bottom wall 12 of the container base 11.

Further, on the inner surface of the ultraviolet ray take-out window 15 of the vacuum container 10, a charge remaining preventing member 45 for preventing the inner surface of the ultraviolet ray take-out window 15 from being charged is provided. The charge residue preventing member 45 of this example is formed by stripe in which a plurality of metal wires are separated from each other and arranged in parallel, and an ultraviolet light transmitting portion is formed by a gap between the metal wires.

The semiconductor light emitting element 20 and the electron beam source 30 are electrically connected to an electron beam (not shown) that is drawn from the inside of the vacuum chamber 10 to the outside, and is electrically connected to the outside of the vacuum vessel 10 for applying an acceleration voltage. Means (omitted from illustration). Further, the electron beam source 30 and the electron beam focusing electrode 40 are electrically connected to the outside of the vacuum container 10 via an electrically conductive wire (not shown) that is pulled out from the inside of the vacuum chamber 10 to make the electrons A beam-focusing electron beam focusing power supply (not shown).

As a material of the container base 11 constituting the vacuum container 10, an insulator such as glass such as quartz glass or ceramic such as alumina can be used.

Further, as a material constituting the ultraviolet ray take-up window 15 of the vacuum container 10, a light that can transmit light from the semiconductor light-emitting element 20 is used, and for example, quartz glass, sapphire or the like can be used.

Further, the pressure inside the vacuum vessel 10 is, for example, 10 ^-4 to 10 ^-6 Pa.

The container base 11 is exemplified as an example of the size of the vacuum container 10. The outer shape has a size of 40 mm × 40 mm × 20 mm, the container base 11 has a thickness of 2 mm, the container base 11 has an opening of 36 mm × 36 mm, and the ultraviolet ray take-up window 15 has a size of 40 mm × 40 mm × 2 mm.

The support surface 17 of the support member 16 is formed in a state of being inclined with respect to the ultraviolet ray take-up window 15, but it is preferable that the angle of inclination of the support surface 17 with respect to the ultraviolet ray take-up window 15 is 15 to 45 degrees. When the inclination angle is less than 15°, the incident angle of the electron beam from the electron beam source 30 on one surface of the semiconductor light emitting element 20 is reduced, so that the electron beam hardly enters the inside of the active layer of the semiconductor light emitting element 20, so that the electron beam hardly enters the inside of the active layer of the semiconductor light emitting element 20, The luminous efficiency of the semiconductor light emitting element 20 is lowered. On the other hand, when the inclination angle exceeds 45°, it is difficult to take out the ultraviolet rays emitted from the semiconductor light-emitting element 20 from the ultraviolet ray take-out window 15 to the outside, and therefore the extraction efficiency of ultraviolet rays is lowered.

Moreover, as the material constituting the support member 16, a metal having high thermal conductivity such as copper or a diamond or the like can be used.

As shown in FIG. 2, the semiconductor light emitting element 20 is formed on one surface of the buffer layer 22, for example, by a substrate 21 made of sapphire, a buffer layer 22 made of, for example, AlN formed on one surface of the substrate 21. And consisting of an active layer 25 having a single quantum well structure or a multiple quantum well structure.

In the semiconductor light-emitting device 20 of this example, the substrate 21 is bonded to the support surface 17 of the support member 16 by welding or the like in a state where the active layer 25 faces the ultraviolet ray take-up window 15 of the vacuum container 10.

The thickness of the substrate 21 is, for example, 10 to 1000 μm, and the thickness of the buffer layer 22 is The degree is, for example, 100 to 1000 nm.

Further, the distance between the active layer 25 of the semiconductor light emitting element 20 and the electron beam source 30 is, for example, 5 to 15 mm.

Further, the distance between the surface 20a of the semiconductor light-emitting element 20 that emits ultraviolet rays and the inner surface of the ultraviolet ray take-up window 15 is, for example, 3 to 25 mm.

The active layer 25 is a single quantum well structure or a multiple quantum well structure formed by In _x Al _y Ga _1-xy N (0≦x<1, 0<y≦1, x+y≦1), single or plural The quantum well layer 26 and the single or complex barrier layer 27 are formed on the buffer layer 22 in this order.

The respective thicknesses of the quantum well layers 26 are, for example, 0.5 to 50 nm. Further, the barrier layer 27 is selected to have a band gap larger than that of the quantum well layer 26. For example, AlN may be used, and each thickness is set to be larger than the well width of the quantum well layer 26, specifically, for example, 1~ 100nm.

The period of the quantum well layer 26 constituting the active layer 25 is appropriately set in consideration of the thickness of the entire quantum well layer 26, the barrier layer 27, and the active layer 25, and the acceleration voltage of the electron beam to be used, but is usually 1~. 100.

The semiconductor light emitting element 20 described above can be formed, for example, by an MOCVD method (organic metal chemical vapor deposition method). Specifically, a carrier gas made of hydrogen and nitrogen is used, and a raw material gas made of trimethylaluminium and ammonia is vapor-deposited on the (0001) surface of the substrate 21 made of sapphire. Thereby, after forming the buffer layer 22 made of AlN having a required thickness, by using a carrier gas formed of hydrogen gas and nitrogen gas, and by trimethyl aluminum, trimethylgallium, and trimethyl A raw material gas of trimethylindium and ammonia is vapor-deposited on the buffer layer 22 to form a desired thickness having an In _x Al _y Ga _1-xy N (0≦x<1,0<y≦1, The single-quantum well structure or the active layer 25 of the multi-quantum well structure formed by x+y≦1), whereby the semiconductor light-emitting element 20 can be formed.

In the respective formation processes of the buffer layer 22, the quantum well layer 26, and the barrier layer 27, conditions such as processing temperature, processing pressure, and deposition rate of each layer are required to form the buffer layer 22, the quantum well layer 26, and The composition, thickness, and the like of the barrier layer 27 are appropriately set.

Further, when the quantum well layer 26 made of InAlGaN is formed, as the source gas, in addition to the above, trimethylindium is used, and the treatment temperature is set lower than the formation of the quantum well layer 26 formed of AlGaN. .

Further, the method of forming the semiconductor multilayer film is not limited to the MOCVD method, and for example, an MBE method (molecular beam epitaxy method) or the like may be used.

As shown in FIG. 3, in the electron beam emitting portion 32 of the electron beam source 30, a plurality of carbon nanotubes are formed on the support substrate 31, and the support substrate 31 of the electron beam source 30 is fixed to the plate-like base. Block 33. Further, in the electron beam source 30, a mesh-shaped extraction electrode 35 for discharging electrons from the electron beam emitting portion 32 is disposed to be disposed away from the electron beam emitting portion 32, and the extraction electrode 35 is held by the electrode. The member 36 is fixed to the base 33. The support substrate 31 and the extraction electrode 35 are electrically connected to a power supply for discharging an electron beam (not shown) provided outside the vacuum container 10 via a conductive wire (not shown) that is pulled out from the inside of the vacuum container 10 to the outside. .

When the size of the electron beam source 30 is taken as an example, the size of the support substrate 31 is 10 mm. , the thickness is 0.15 mm, and the size of the electron beam emitting portion 32 is 3 mm. The thickness was 0.025 mm, and the area of the surface of the electron beam emitted from the electron beam emitting portion 32 was 7 mm ² .

As a material constituting the support substrate 31, a metal material containing any of iron, nickel, cobalt, and chromium can be used.

The method of forming the electron beam emitting portion 32 formed of the carbon nanotube on the support substrate 31 is not particularly limited, and a known method can be used. For example, a metal catalyst layer can be formed on the surface by heating. The support substrate 31 is supplied with carbon source gas such as CO or acetylene, and carbon is deposited on the metal catalyst layer formed on the surface of the support substrate 31 to form a carbon nanotube tube by thermal CVD method and modulation by arc discharge method. The powder of the carbon nanotube formed and the organic binder are contained in a paste formed in a liquid medium, and the paste is applied by screen printing to a surface of the support substrate 31 and dried. Printing method, etc.

Further, as a material constituting the extraction electrode 35, a metal material containing any one of iron, nickel, cobalt, and chromium can be used.

As a material constituting the electron beam focusing electrode 40, a metal material containing any of iron, nickel, cobalt, chromium, aluminum, silver, copper, titanium, or zirconium can be used.

As an example of the size of the electron beam focusing electrode 40, the inner diameter is 7 to 10 mm, the outer diameter is 9 to 12 mm, and the thickness is 0.1 to 1 mm.

The material constituting the charge remaining prevention member 45 is, as a material for forming the metal wire of the charge remaining prevention member 45, in the illustrated example. As the material, metals such as aluminum, silver, gold, platinum, stainless steel, chromium, nickel, titanium, zirconium or the like can be used.

In the case of an example of the size of the metal wire forming the charge remaining prevention member 45, for example, the width of the metal wire is 100 μm, the thickness is 20 μm, and the arrangement pitch of the metal wires is 1500 μm.

In the above-described electron beam excitation type ultraviolet radiation device, when a voltage is applied between the electron beam source 30 and the extraction electrode 35, electrons are emitted from the electron beam radiation source 32 of the electron beam source 30 toward the extraction electrode 35. This electron is accelerated toward the semiconductor light emitting element 20 by an acceleration voltage applied between the semiconductor light emitting element 20 and the electron beam source 30 to form an electron beam. The electron beam is focused toward the semiconductor light emitting element 20 by the electron beam focusing electrode 40, and is incident from the surface 20a of the semiconductor light emitting element 20, that is, the surface of the active layer 25 to the inside. Then, in the semiconductor light emitting element 20, the active layer 25 is excited by injecting an electron beam. Thereby, ultraviolet rays are emitted from the surface 20a of the semiconductor light-emitting element 20 that is incident on the electron beam, and are transmitted through the ultraviolet ray take-out window 15 of the vacuum container 10, and are emitted outside the vacuum container 10.

The voltage applied between the electron beam source 30 and the extraction electrode 35 is, for example, 1 to 5 kV.

Further, the acceleration voltage of the electron beam is preferably 8 to 13 kV. When the acceleration voltage is too small, it is difficult to obtain high-output ultraviolet rays. On the other hand, when the accelerating voltage is excessively large, X-rays are easily generated from the semiconductor light-emitting element 20, and the semiconductor light-emitting device 20 is easily damaged by the energy of the electron beam, which is not preferable.

Further, the voltage applied between the electron beam source 30 and the electron beam focusing electrode 40 is, for example, -0.1 to -2 kV.

In such an electron beam excitation type ultraviolet radiation device, the support surface 17 of the support member 16 in which the semiconductor light emitting element 20 is disposed is inclined with respect to the ultraviolet ray extraction window 15. Therefore, even in the case where the electron beam source 30 is disposed at the peripheral position of the semiconductor light emitting element 20, the incident angle of the electron beam from the electron beam source 30 with respect to one surface of the semiconductor light emitting element 20 can be sufficiently increased. Therefore, the electron beam can be efficiently incident on the semiconductor light emitting element 20, and can emit high-output ultraviolet rays.

Moreover, since the electron beam source 30 can be disposed at the peripheral position of the semiconductor light emitting element 20, it is possible to reduce the size of the device.

Moreover, since the support member 16 in which the semiconductor light emitting element 20 is disposed has high thermal conductivity, the semiconductor light emitting element 20 can be efficiently cooled via the support member 16. Therefore, the luminous efficiency of the semiconductor light emitting element 20 is not lowered, and high-output ultraviolet rays can be maintained.

Further, since the support member has a plurality of support faces, the semiconductor light-emitting elements are arranged close to each other on each of the support faces, and the radiation area of the ultraviolet rays is increased, and the high-output ultraviolet rays can be further maintained.

In the above, the embodiment of the electron beam excitation type ultraviolet radiation device of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications can be applied as will be described later.

For example, in the example shown in FIG. 4, at the front end of the support member 16, a support surface 17 which is inclined with respect to the ultraviolet ray take-up window 15 is formed. In the support surface 17, in a posture in which the surface 20a is inclined with respect to the ultraviolet ray take-out window 15, The plurality of (four in the illustrated example) semiconductor light emitting elements 20 are arranged close to each other. The one electron beam source 30 is disposed at a position around the semiconductor light emitting element 20 in a posture in which the electron beam emitting portion 32 faces the respective surfaces 20a of the semiconductor light emitting element 20.

Further, in the example shown in FIG. 5, four fan-shaped support faces 17 which are inclined toward the ultraviolet ray take-up window 15 are formed at the front end of the support member 16. On the support faces 17, the semiconductor light-emitting elements 20 are disposed close to each other in a posture in which the surface 20a is inclined with respect to the ultraviolet ray take-up window 15. At each peripheral position of the semiconductor light-emitting elements 20, the semiconductor light-emitting elements 20 are arranged, and the four electron beam sources 30 are disposed in such a manner that the electron beam emitting portion 32 faces the surface 20a of the semiconductor light-emitting elements 20.

10‧‧‧Vacuum container

11‧‧‧ Container base

12‧‧‧ bottom wall

13a, 13b‧‧‧ side wall

15‧‧‧UV removal window

16‧‧‧Support components

17‧‧‧Support surface

20‧‧‧Semiconductor light-emitting elements

20a‧‧‧ surface

30‧‧‧Electronic beam source

31‧‧‧Support substrate

32‧‧‧Electron beam release department

35‧‧‧Extraction electrode

37‧‧‧ Keeping components

40‧‧‧electron beam focusing electrode

41‧‧‧ Keeping components

45‧‧‧ Charge residue prevention member

Claims (4)

An electron beam excitation type ultraviolet radiation device comprising: a vacuum container having an ultraviolet ray extraction window; and a high thermal conductivity supporting member provided in the vacuum container and having a support surface inclined to the ultraviolet ray extraction window; The light-emitting element is disposed on the support surface of the support member, and the electron beam source supplies an electron beam to the semiconductor light-emitting element. The electron beam excitation type ultraviolet radiation device according to the first aspect of the invention, wherein the support member has a plurality of the support surfaces, and the semiconductor light-emitting elements are arranged close to each other on each of the support surfaces. The electron beam excitation type ultraviolet radiation device according to claim 2, wherein the electron beam source is provided corresponding to each of the semiconductor light emitting elements. The electron beam excitation type ultraviolet radiation device according to any one of the first to third aspect, wherein the electron beam focusing electrode is provided, and the electron beam from the electron beam source is directed to the front side The semiconductor light emitting element is focused.