JP5299405B2 - Electron beam excitation type light source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron beam excitation type light source capable of radiating electron beam uniformly on one surface of a semiconductor light-emitting element, providing high light output without increasing an acceleration voltage of the electron beam, and efficiently cooling the semiconductor light-emitting element. <P>SOLUTION: An electron beam excitation type light source comprises an electron beam source, and a semiconductor light-emitting element excited by electron beam radiated from the electron beam source. The electron beam source has a planar electron beam emission part, and is arranged around the semiconductor light-emitting element. The light is radiated from a surface on which the electron beam from the electron beam source of the semiconductor light-emitting element is incident. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to an electron beam excitation light source including an electron beam source and a semiconductor light emitting element excited by an electron beam emitted from the electron beam source.

An electron beam excitation type light source that emits light from a semiconductor light emitting element by emitting an electron beam is expected as a light source that emits ultraviolet light with a small size and high output.
FIG. 7 is a cross-sectional view for explaining the outline of the configuration of an example of a conventional electron beam excitation type light source. This electron beam excitation type light source emits laser light, and includes a vacuum container 80 having a light transmission window 81 sealed inside in a negative pressure state. A laser structure 85 having light reflecting members 83 and 84 disposed on both sides of the semiconductor light emitting element 82 is disposed on the inner surface of the transmission window 81, and the semiconductor light emitting element 82 is disposed on the inner surface of the bottom wall of the vacuum vessel 80. An electron beam source 86 for irradiating an electron beam is disposed so as to face the laser structure 85. The semiconductor light emitting element 82 and the electron beam source 86 are electrically connected to an electron acceleration means 87 for applying an acceleration voltage provided outside the vacuum vessel 80. An electron beam excitation light source having such a configuration is described in Patent Document 1.

  In the above-described electron beam excitation light source, electrons emitted from the electron beam source 86 are accelerated by an acceleration voltage applied between the semiconductor light emitting element 82 and the electron beam source 86 to form an electron beam. When the electron beam is incident on the semiconductor light emitting element 82 via the light reflecting member 84, light is emitted from the semiconductor light emitting element 82, and this light is resonated by the light reflecting members 83 and 84, so that laser light is emitted. Is radiated to the outside through the light transmission window 81.

However, in the above-described electron beam excitation light source, the semiconductor light emitting element 82 generates heat when irradiated with an electron beam, but one surface of the semiconductor light emitting element 82 is used as a light emitting surface, and the other surface is incident with an electron beam. Since the semiconductor light emitting device 82 is used as a surface, the semiconductor light emitting device 82 cannot be cooled from either the large surface or the other surface, and therefore it is difficult to efficiently cool the semiconductor light emitting device 82. As a result, the semiconductor light emitting element 82 generates heat to a high temperature, thereby reducing the light emission efficiency of the semiconductor light emitting element 82 and not emitting light with high output. There is a problem that it occurs.
In order to obtain light with high output, it is conceivable to increase the acceleration voltage of the electron beam. However, when the acceleration voltage of the electron beam is increased, X-rays are generated from the semiconductor light emitting element 82. is there.

In order to solve such a problem, an electron beam is incident on one surface of the semiconductor light emitting element from an oblique direction by an electron gun, so that light is emitted from the surface on which the electron beam is incident on the semiconductor light emitting element. An electron beam excitation type light source has been proposed (see Patent Document 2). According to this electron beam excitation type light source, the semiconductor light emitting element can be efficiently cooled from the back surface thereof, so that the semiconductor light emitting element can be efficiently cooled, and thus the light emission efficiency of the semiconductor light emitting element is lowered. High output light is maintained without doing so.
However, in such an electron beam excitation type light source, since an electron gun is used to irradiate the semiconductor light emitting element with an electron beam, it is impossible to uniformly irradiate one surface of the semiconductor light emitting element. Since the electron beam is locally focused and irradiated on one surface, there is a problem that the semiconductor light emitting element is deteriorated at an early stage.

Japanese Patent No. 3667188 Japanese Patent Laid-Open No. 09-214027

  The present invention has been made based on the circumstances as described above, and an object thereof is to uniformly irradiate one surface of a semiconductor light emitting device with an electron beam and to increase the acceleration voltage of the electron beam. An object of the present invention is to provide an electron beam excitation light source that can obtain a high light output without any problem and can efficiently cool a semiconductor light emitting element.

An electron beam excitation type light source of the present invention is an electron beam excitation type light source comprising an electron beam source and a semiconductor light emitting element excited by an electron beam emitted from the electron beam source.
The electron beam source has a planar electron beam emitting portion, and is disposed so as to surround the semiconductor light emitting element around the semiconductor light emitting element,
Electrons from the electron beam source are incident on the surface of the semiconductor light emitting device as an electron beam by an acceleration voltage applied between the semiconductor light emitting device and the electron beam source,
In the semiconductor light emitting device, light is emitted from a surface on which an electron beam from the electron beam source is incident.

In the electron beam excitation light source of the present invention, it is preferable that the electron beam emitting portion is composed of carbon nanotubes.
The electron beam source may be formed of an annular belt surrounding the semiconductor light emitting element.
In addition, a plurality of the electron beam sources each made of a partially annular belt may be arranged so as to surround the semiconductor light emitting element.

According to the electron beam excitation type light source of the present invention, the electron beam source having the planar electron beam emitting portion is arranged so as to surround the semiconductor light emitting device in the periphery of the semiconductor light emitting device. An electron beam can be irradiated uniformly and a high light output can be obtained without increasing the acceleration voltage of the electron beam. Moreover, since light is emitted from the surface of the semiconductor light emitting device on which the electron beam from the electron beam source is incident, the semiconductor light emitting device can be cooled from the other surface of the semiconductor light emitting device. Therefore, since the semiconductor light emitting device can be efficiently cooled, the light emission efficiency of the semiconductor light emitting device is not lowered and high output light is maintained.

It is explanatory drawing which shows the outline of a structure in the electron beam excitation type light source which concerns on the 1st Embodiment of this invention, (A) is side sectional drawing, (B) is a plane which shows the state which removed the light transmissive window FIG. It is sectional drawing for description which shows the structure of the semiconductor light-emitting device in the electron beam excitation light source which concerns on 1st Embodiment. It is sectional drawing for description which shows the structure of the electron beam source in the electron beam excitation type light source which concerns on 1st Embodiment. It is explanatory drawing which shows the outline of a structure in the electron beam excitation type light source which concerns on the 2nd Embodiment of this invention, (A) is side sectional drawing, (B) is a plane which shows the state which removed the light transmissive window FIG. It is explanatory drawing which shows the outline of a structure in the electron beam excitation type light source which concerns on the 3rd Embodiment of this invention, (A) is side sectional drawing, (B) is a plane which shows the state which removed the light transmissive window FIG. It is sectional drawing for description which shows the outline of a structure of the modification of the electron beam excitation light source which concerns on 3rd Embodiment. It is sectional drawing for description which shows the outline of a structure in an example of the conventional electron beam excitation type light source.

1A and 1B are explanatory views showing an outline of the configuration of the electron beam excitation light source according to the first embodiment of the present invention. FIG. 1A is a side sectional view, and FIG. It is a top view which shows a state.
This electron beam excitation type light source has a vacuum container 10 whose outer shape is sealed in a negative pressure state and has a rectangular parallelepiped shape, and this vacuum container 10 has an opening on one surface (the upper surface in FIG. 1A). A container base 11 and a light transmission window 15 disposed in the opening of the container base 11 and hermetically sealed to the container base 11 are configured.

In the vacuum vessel 10, the semiconductor light emitting element 20 is disposed such that the surface (upper surface in FIG. 1) 20a faces the light transmission window 15 with a space therebetween, specifically, a peripheral region of the semiconductor light emitting element 20, specifically, An electron beam source in which a planar electron beam emitting portion 32 is formed on a support substrate 31 in a region close to the semiconductor light emitting device 20 other than a region on the front surface and a region on the back surface of the semiconductor light emitting device 20. 30 is arranged so as to surround the semiconductor light emitting element 20. Specifically, the electron beam source 30 is formed of an annular belt-like body, and the semiconductor light emitting element is configured such that the surface of the electron beam emitting portion 32 on which the electron beam is emitted faces the light transmission window 15 of the vacuum vessel 10. In this state, it is fixed to the bottom wall of the container base 11 in the vacuum container 10 via the support member 37. The semiconductor light emitting element 20 and the electron beam source 30 are electrons provided to the outside of the vacuum vessel 10 for applying an acceleration voltage via a conductive wire (not shown) drawn from the inside of the vacuum vessel 10 to the outside. It is electrically connected to acceleration means (not shown).
In addition, the semiconductor light emitting element 20 is fixed to the bottom wall of the container base 11 in the vacuum container 10 via the high thermal conductive member 16 provided on the back surface 20b.

As a material constituting the container base 11 in the vacuum container 10, an insulator such as glass such as quartz glass and ceramics such as alumina can be used.
Moreover, as a material which comprises the light transmission window 15 in the vacuum vessel 10, the material which can permeate | transmit the light from the semiconductor light-emitting device 20 is used, For example, quartz glass, sapphire, etc. can be used.
Moreover, the pressure inside the vacuum vessel 10 is, for example, 10 ⁻⁴ to 10 ⁻⁶ Pa.
An example of the dimensions of the vacuum container 10 is that the outer dimensions of the container base 11 are 40 mm × 40 mm × 20 mm, the thickness of the container base 11 is 2 mm, the opening of the container base 11 is 36 mm × 36 mm, and the light transmission window 15 The dimensions are 40 mm × 40 mm × 2 mm.

  As a material constituting the high heat conductive member 16, a metal having high heat conductivity such as copper, diamond, or the like can be used.

As shown in FIG. 2, the semiconductor light emitting device 20 is formed on a substrate 21 made of, for example, sapphire, a buffer layer 22 made of, for example, AlN formed on one surface of the substrate 21, and on one surface of the buffer layer 22. The active layer 25 has a single quantum well structure or a multiple quantum well structure.
In the semiconductor light emitting device 20 in this example, the substrate 21 is bonded to the high thermal conductive member 16 by brazing or the like with the active layer 25 facing the light transmission window 15 in the vacuum vessel 10.
The thickness of the substrate 21 is, for example, 10 to 1000 μm, and the thickness of the buffer layer 22 is, for example, 100 to 1000 nm.
Moreover, the separation distance between the active layer 25 and the electron beam source 30 in the semiconductor light emitting device 20 is, for example, 5 to 15 mm.
Further, the distance between the light emitting surface of the semiconductor light emitting element 20 and the inner surface of the light transmission 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 consisting of each _{In x Al y Ga 1-xy} N (0 ≦ x <1,0 <y ≦ 1, x + y ≦ 1), a single or A plurality of quantum well layers 26 and a single or a plurality of barrier layers 27 are alternately stacked on the buffer layer 22 in this order.
The thickness of each quantum well layer 26 is, for example, 0.5 to 50 nm. The barrier layer 27 has a composition selected such that the forbidden band width is larger than that of the quantum well layer 26. For example, AlN may be used, and each thickness is larger than the well width of the quantum well layer 26. It is set to be large, specifically, for example, 1 to 100 nm.
The period of the quantum well layer 26 constituting the active layer 25 is appropriately set in consideration of the total thickness of the quantum well layer 26, the barrier layer 27 and the active layer 25, the acceleration voltage of the electron beam used, etc. 1 to 100.

  The semiconductor light emitting element 20 can be formed by, for example, MOCVD (metal organic chemical vapor deposition). Specifically, by using a carrier gas composed of hydrogen and nitrogen and a source gas composed of trimethylaluminum and ammonia, vapor deposition is performed on the (0001) plane of the sapphire substrate 21 to have a required thickness. After forming the buffer layer 22 made of AlN, vapor phase growth is performed on the buffer layer 22 using a carrier gas made of hydrogen gas and nitrogen gas and a source gas made of trimethylaluminum, trimethylgallium, trimethylindium and ammonia. Thus, the active layer 25 having a single quantum well structure or a multiple quantum well structure made of Inx Aly Ga1-xy N (0 ≦ x <1, 0 <y ≦ 1, x + y ≦ 1) having a required thickness is formed. Thus, the semiconductor light emitting element 20 can be formed.

In each step of forming the buffer layer 22, the quantum well layer 26, and the barrier layer 27, conditions such as a processing temperature, a processing pressure, and a growth rate of each layer are determined according to the buffer layer 22, the quantum well layer 26, and the barrier layer 27 to be formed. It can set suitably according to a composition, thickness, etc. of this.
In addition, when forming the quantum well layer 26 made of InAlGaN, trimethylindium is used as a source gas in addition to the above, and the processing temperature is set lower than when the quantum well layer 26 made of AlGaN is formed. That's fine.
The method for 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 can also be used.

As shown in FIG. 3, the electron beam emitter 32 in the electron beam source 30 is formed by supporting a large number of carbon nanotubes on a support substrate 31, and the support substrate 31 in the electron beam source 30 is a plate. It is being fixed on the base 33 of a shape. Further, above the electron beam emitting portion 32 in the electron beam source 30, a net-like extraction electrode 35 for emitting electrons from the electron beam emitting portion 32 is disposed so as to face the electron beam emitting portion 32 with a distance therebetween. The lead electrode 35 is fixed to the base 33 via the electrode holding member 36. The support substrate 31 and the extraction electrode 35 are connected to an electron beam emission power source (not shown) provided outside the vacuum vessel 10 via a conductive wire (not shown) drawn from the inside of the vacuum vessel 10 to the outside. Electrically connected.
As an example of the dimensions of the electron beam source 30, the outer diameter of the support substrate 31 is 25 mm, the inner diameter is 19 mm, the thickness is 0.1 mm, the outer diameter of the electron beam emitting portion 32 is 24 mm, the inner diameter is 20 mm, and the thickness is 0. The area of the surface from which the electron beam is emitted in the electron beam emitting portion 32 is 138 mm ² .

As a material constituting the support substrate 31, a metal material containing iron, nickel, cobalt, or chromium can be used.
A method for forming the electron beam emitting portion 32 made of carbon nanotubes on the support substrate 31 is not particularly limited, and a known method can be used. For example, the support substrate 31 having a metal catalyst layer formed on the surface is heated. , By supplying a carbon source gas such as CO or acetylene, and depositing carbon on the metal catalyst layer formed on the surface of the support substrate 31 to form carbon nanotubes. It is preferable to use a screen printing method or the like in which a paste containing carbon nanotube powder and an organic binder in a liquid medium is prepared, and this paste is applied to the surface of the support substrate 31 by screen printing and dried. it can.
In addition, as a material constituting the extraction electrode 35, a metal material containing any of iron, nickel, cobalt, and chromium can be used.

In the electron beam excitation light source, when a voltage is applied between the electron beam source 30 and the extraction electrode 35, electrons are emitted from the electron beam emitting portion 32 of the electron beam source 30 toward the extraction electrode 35. The electrons travel while being 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 and are converted into an electron beam on the surface 20a of the semiconductor light emitting element 20, that is, the activity. Incident on the surface of the layer 25. In the semiconductor light emitting device 20, the electrons in the active layer 25 are excited by the incidence of the electron beam, and as a result, light such as ultraviolet rays is emitted from the surface of the semiconductor light emitting device 20 on which the electron beam is incident. The light is emitted to the outside of the vacuum vessel 10 through the light transmission window 15 in the vacuum vessel 10.
In the above, the voltage applied between the electron beam source 30 and the extraction electrode 35 is, for example, 1 to 5 kV.
Moreover, it is preferable that the acceleration voltage of an electron beam is 6-12 kV. When the acceleration voltage is too small, it becomes difficult to obtain a high light output. On the other hand, if the acceleration voltage is excessive, X-rays are likely to be generated from the semiconductor light emitting element 20, and the semiconductor light emitting element 20 is easily damaged by the energy of the electron beam, which is not preferable.

  According to such an electron beam excitation light source, the electron beam source 30 formed of an annular belt having a planar electron beam emitting portion 32 surrounds the semiconductor light emitting element 20 around the semiconductor light emitting element 20. Thus, the surface 20a of the semiconductor light emitting element 20 can be uniformly irradiated with an electron beam, and a high light output can be obtained without increasing the acceleration voltage of the electron beam. Moreover, since light is emitted from the front surface 20a of the semiconductor light emitting device 20 on which the electron beam from the electron beam source 30 is incident, the semiconductor light emitting device 20 is connected to the semiconductor light emitting device 20 from the back surface 20b via the high thermal conductive member 16. It is possible to cool. Therefore, since the semiconductor light emitting element 20 can be efficiently cooled, the light emission efficiency of the semiconductor light emitting element 20 is not lowered and high output light is maintained.

FIGS. 4A and 4B are explanatory views showing an outline of the configuration of the electron beam excitation light source according to the second embodiment of the present invention. FIG. 4A is a side sectional view, and FIG. It is a top view which shows a state.
In this electron beam excitation light source, a plurality of (four in the illustrated example) electron beams each having a planar electron beam emitting portion 32 formed on a support substrate 31 in the peripheral region of the semiconductor light emitting element 20. A source 30 is arranged so as to surround the semiconductor light emitting element 20. Specifically, each of the electron beam sources 30 is formed of a partially annular band, and the surface on which the electron beam is emitted from the electron beam emitting portion 32 faces the light transmission window 15 of the vacuum vessel 10. It arrange | positions so that the said semiconductor light-emitting device 20 may be enclosed along the circle | round | yen centering on the semiconductor light-emitting device 20, and it is being fixed to the bottom wall of the container base | substrate 11 in the vacuum vessel 10 via the support member 37 in this state.
Other specific configurations are the same as those of the electron beam excitation light source according to the first embodiment.

  According to such an electron beam excitation type light source, a plurality of electron beam sources 30 each having a planar electron beam emitting portion 32 and made of a partially annular belt-like body are disposed around the semiconductor light emitting element 20. Since the surface 20a of the semiconductor light emitting device 20 is uniformly irradiated with the electron beam, a high light output can be obtained without increasing the acceleration voltage of the electron beam. Moreover, since light is emitted from the front surface 20a of the semiconductor light emitting device 20 on which the electron beam from the electron beam source 30 is incident, the semiconductor light emitting device 20 is connected to the semiconductor light emitting device 20 from the back surface 20b via the high thermal conductive member 16. It is possible to cool. Therefore, since the semiconductor light emitting element 20 can be efficiently cooled, the light emission efficiency of the semiconductor light emitting element 20 is not lowered and high output light is maintained.

FIGS. 5A and 5B are explanatory views showing an outline of the configuration of the electron beam excitation light source according to the third embodiment of the present invention. FIG. 5A is a side sectional view, and FIG. It is a top view which shows a state.
In this electron beam excitation type light source, the semiconductor light emitting element 20 is disposed on the inner surface of the bottom wall of the container base 11 in the vacuum container 10 and the surface (the upper surface in FIG. In the peripheral region of the semiconductor light emitting device 20, a plurality of (two in the illustrated example) are formed by forming rectangular planar electron beam emitting portions 32 on a rectangular support substrate 31, respectively. The electron beam source 30 is disposed at a position sandwiching the semiconductor light emitting element 20. Specifically, the electron beam emitter 32 in each of the electron beam sources 30 is formed by supporting a large number of carbon nanotubes on the support substrate 31, and the support substrate 31 in each of the electron beam sources 30 is Each of the electron beam sources 30 fixes the semiconductor light emitting element 20 by fixing each base plate 33 to the inner surfaces of two opposite side walls of the container base 11. The electron beam emitting portions 32 are arranged so as to face each other at the sandwiched position. Other specific configurations are the same as those of the electron beam excitation light source shown in FIG.

  According to such an electron beam excitation type light source, a plurality of electron beam sources 30 having a planar electron beam emitting portion 32 are arranged at a position sandwiching the semiconductor light emitting element 20 around the semiconductor light emitting element 20. Therefore, the surface 20a of the semiconductor light emitting element 20 can be uniformly irradiated with an electron beam, and a high light output can be obtained without increasing the acceleration voltage of the electron beam. Moreover, since light is emitted from the front surface 20a of the semiconductor light emitting device 20 on which the electron beam from the electron beam source 30 is incident, the semiconductor light emitting device 20 can be cooled from the back surface 20b of the semiconductor light emitting device 20. . Therefore, since the semiconductor light emitting element 20 can be efficiently cooled, the light emission efficiency of the semiconductor light emitting element 20 is not lowered and high output light is maintained.

As mentioned above, although the embodiment of the electron beam excitation light source of the present invention has been described, the present invention is not limited to the above embodiment, and various modifications can be made as follows.
In the electron beam excitation light source of the present invention, the specific shape of the electron beam source is not particularly limited as long as it has a planar electron beam emitting portion. The arrangement position of the electron beam source is not particularly limited as long as the electron beam source is positioned around the semiconductor light emitting element and can enter the electron beam on the light emitting surface of the semiconductor light emitting element. For example, in the electron beam excitation light source according to the third embodiment, the electron beam source 30 has an electron beam emitting portion 32 at the semiconductor light emitting element 20 at a position sandwiching the semiconductor light emitting element 20 as shown in FIG. It may be arranged to face.
Moreover, the electron beam emission part 32 in the electron beam source 30 is not limited to what consists of carbon nanotubes, The thing of various structures can be used if it is planar.

DESCRIPTION OF SYMBOLS 10 Vacuum vessel 11 Container base | substrate 15 Light transmission window 16 High heat conductive member 20 Semiconductor light emitting element 20a Front surface 20b Back surface 21 Substrate 22 Buffer layer 25 Active layer 26 Quantum well layer 27 Barrier layer 30 Electron beam source 31 Support substrate 32 Electron emission part 33 Base 35 Extraction electrode 36 Electrode holding member 37 Support member 80 Vacuum vessel 81 Light transmission window 82 Semiconductor light emitting element 83, 84 Light reflection member 85 Laser structure 86 Electron beam source 87 Electron acceleration means

Claims (4)

In an electron beam excitation type light source comprising an electron beam source and a semiconductor light emitting element excited by an electron beam emitted from the electron beam source,
The electron beam source has a planar electron beam emitting portion, and is disposed so as to surround the semiconductor light emitting element around the semiconductor light emitting element,
Electrons from the electron beam source are incident on the surface of the semiconductor light emitting device as an electron beam by an acceleration voltage applied between the semiconductor light emitting device and the electron beam source,
An electron beam excitation light source, wherein light is emitted from a surface of the semiconductor light emitting device on which an electron beam from the electron beam source is incident.
  The electron beam excitation light source according to claim 1, wherein the electron beam emitting portion is composed of carbon nanotubes. The electron beam excitation light source according to claim 1, wherein the electron beam source is formed of an annular belt surrounding the semiconductor light emitting element . 3. The electron beam excitation light source according to claim 1 , wherein a plurality of the electron beam sources each formed of a partially annular belt are arranged so as to surround the semiconductor light emitting element .

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