JP2006221979A - Vehicle lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle lamp having a high extraction efficiency of emitted light. <P>SOLUTION: The vehicle lamp 1 comprises a positive electrode 23 and a negative electrode 21 which are arranged mutually separated each other and form a first electric field, and a phosphor 25 which is composed of a phosphor substance. Electrons emitted from the negative electrode 21 are accelerated by the first electric field toward the positive electrode 23 and emit light by exciting the fluorescent substance of the phosphor 25. The light emitted from the phosphor 25 on the opposite side of the light emitting direction is reflected by the reflector 11 in the light emitting direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicular lamp used for a vehicle lamp, a marker lamp, and the like.

  Vehicles such as four-wheeled vehicles and two-wheeled vehicles are provided with various vehicle lamps designed according to the application. For example, the vehicle is provided with a vehicle headlamp in order to improve forward visibility when traveling at night, and a direction indicator that indicates the turning direction as an indication of the state of the vehicle relative to other vehicles, A marker lamp such as a brake lamp indicating a brake braking state is provided. Various light sources can be used as the light source used in these vehicle lamps. For example, incandescent bulbs using filaments, halogen lamps using halogen gas, discharge lamps using arc discharge (so-called HID lamps) : High Intensity Discharge Lamp)).

  In recent years, LED lamps using light emitting diodes (LEDs) have also been developed. LEDs are characterized by high brightness and low power consumption, and are expected as next-generation vehicle light sources.

  As a next-generation light source, a field emission lamp (FEL) that emits light by accelerating electrons emitted from an electron source and colliding with the phosphor to excite the phosphor has been proposed. Yes. As this type of lamp, for example, a lamp described in Patent Document 1 can be cited.

In the lamp disclosed in Patent Document 1, a flat plate-like anode and a cathode are arranged to face each other, electrons are accelerated from the cathode to the anode, and the phosphor arranged on the anode is excited by the kinetic energy of the electrons to be visible. The light is emitted in one direction. Further, in this lamp, Patent Document 1 discloses that the magnetic axis between the anode and the cathode is variably controlled by an electromagnet to change the trajectory of electrons to change the optical axis.
JP 2004-193040 A

  In the field emission lamp as described above, light emitted from the phosphor emits isotropically in all directions without depending on the incident direction of electrons incident on the phosphor. Therefore, when trying to extract light in a certain direction, the amount of light extracted is simply reduced to less than half of the total light emission amount, and there is a problem that the efficiency of extracting emitted light is low.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicular lamp having high emission light extraction efficiency.

The above object of the present invention can be achieved by the following constitution.
(1) an anode and a cathode spaced apart from each other to form a first electric field;
A phosphor formed on the anode and made of a fluorescent material,
A vehicle lamp that emits electrons emitted from the cathode by being accelerated toward the anode by the first electric field to excite the phosphor of the phosphor,
A vehicular lamp comprising a reflector that reflects light emitted from the phosphor in a direction opposite to a light emitting direction in the light emitting direction.
(2) The vehicular lamp according to (1), wherein the reflector is disposed so as to surround a side surface of a space between the anode and the cathode.
(3) The vehicular lamp according to (1) or (2), wherein an inner diameter of the reflector increases from the cathode side toward the anode side.
(4) The vehicular lamp according to any one of (1) to (3), further including a third electrode that is disposed between the anode and the cathode and forms a second electric field. .
(5) The reflector includes a through hole that is disposed between the cathode and the anode and penetrates the outer surface and the inner surface of the reflector.
The vehicular lamp according to (4), wherein the third electrode is disposed in the through hole.
(6) The vehicular lamp according to (4), wherein a wall surface of an inner wall of the hole forming the through hole is parallel to a straight line connecting the anode and the cathode.

  The vehicular lamp according to the present invention includes a reflector that reflects light emitted in the opposite direction to the light emission direction from a phosphor excited by electrons and emitting light. Accordingly, it is possible to provide a bright vehicular lamp by irradiating light emitted in the light emission direction from the phosphor to the opposite side to the light emission direction without increasing use efficiency of light emitted from the phosphor. Is possible.

  Further, the light emitted from the phosphor does not depend on the incident direction of electrons and isotropically emitted, and thus propagates at various angles. Therefore, if the reflector is disposed so as to surround the side surface of the space between the anode and the cathode, the light can be reflected in the light emitting direction regardless of the direction in which the light is emitted from the phosphor. The use efficiency of the light emitted from the body can be improved, and a bright vehicle lamp can be provided.

  In addition, according to the present invention, the inner diameter of the reflector is configured to increase as it proceeds from the cathode toward the anode, thereby reducing the number of times the light emitted from the phosphor is incident on the reflector as much as possible. Light can be irradiated in the light emitting direction. Therefore, attenuation of light due to reflection at the reflector can be suppressed as much as possible to suppress a decrease in light amount, and a bright vehicle lamp can be obtained.

  According to the present invention, a third electrode for forming a second electric field may be provided separately from the first electric field formed between the anode and the cathode. By providing the third electrode, an electric field for extracting electrons can be formed independently of an electric field for accelerating electrons, or a converging electric field for converging electrons emitted from the cathode can be formed.

  Further, according to the present invention, the third electrode may be disposed in the through hole formed in the reflector. In particular, if the third electrode and the reflector are integrally formed, an increase in the number of parts when the vehicle lamp is assembled can be suppressed, and the vehicle lamp can be efficiently assembled.

  Further, according to the present invention, if the wall surface of the inner wall of the hole forming the through hole is parallel to the straight line connecting the anode and the cathode, electrons from the cathode to the anode are not inhibited by the wall surface of the through hole. . Therefore, the anode arrival rate of electrons is improved, the light emission efficiency is improved, and a bright vehicle lamp can be provided.

  Hereinafter, an embodiment of a vehicular lamp according to the present invention will be described with reference to the drawings.

  The vehicular lamp of the present embodiment is a lamp applicable as a lamp such as a head lamp, a fog lamp, a turn signal lamp, a tail lamp, a stop lamp, and a back lamp. Moreover, the vehicular lamp of the present embodiment can be applied as various illumination lamps and marker lamps in addition to the lamp itself attached to the vehicle. In the following description, an embodiment as a vehicular lamp attached to a vehicle will be described as an example.

FIG. 1 is an overall sectional view showing a vehicular lamp 1 according to an embodiment of the present invention.
The vehicular lamp 1 according to the present embodiment is an FEL-type vehicular lamp, and a lamp unit 10 that emits light is disposed in, for example, a lamp chamber 1 a that is covered by a lamp body 2 and a light-transmitting cover 3. Configured. The lamp unit 10 is attached to the lamp body 2 via, for example, aiming mechanisms 5 and 5 that can adjust the optical axis of the lamp unit 10. The vehicular lamp 1 of the present embodiment is a lamp that emits light in a light emitting direction from the lamp unit 10 toward the cover 3 and projects light forward.

FIG. 2 is an enlarged cross-sectional view showing only the lamp unit 10 taken out.
The lamp unit 10 includes a reflector 11 having a substantially bowl shape, a convex lens 13 provided in front of the reflector 11, and a lens holder 15 that positions and attaches the convex lens 13 to the reflector 11.

  The reflector 11 is, for example, a reflecting member in which a reflecting surface 11a having a substantially rotational paraboloid shape with the central axis Ax as an axis is formed on the inner surface side. The reflector 11 includes a substantially circular opening 11b, and the lens holder 15 is fixed along an opening edge 11c that defines the opening 11b. On the other hand, a circular through-hole 12 that penetrates the inner surface and the outer surface of the reflector 11 along the central axis Ax of the reflector 11 is formed at the bottom of the reflector 11 opposite to the opening edge 11c. A through hole cover 17 is attached to the through hole 12 so as to close the through hole 12. The through hole cover 17 hermetically seals the through hole 12.

  The lens holder 15 is a substantially cylindrical support member having one end fixed along the opening edge of the reflector 11. An annular lens holding portion 15b is formed at the other end of the lens holder 15, and the convex lens 13 is fitted to the lens holding portion 15b.

  The convex lens 13 is a lens in which the front side one surface 13a is a convex surface and the rear side other surface 13b has a planar shape, and is fixed to the lens holder 15 so that the convex side is the cover 3 side, that is, the front side.

In this embodiment, the internal space 10 a on the inner surface side of the reflector 11 is airtightly sealed from the outside by the reflector 11, the convex lens 13, the lens holder 15, and the through hole cover 17. In the present embodiment, the internal space 10a has been evacuated and decompressed in advance. In other words, in this embodiment, a vacuum container is formed by the reflector 11, the convex lens 13, the lens holder 15, and the through-hole cover 17. The internal space 10a is preferably evacuated to 10 ⁻⁵ torr or less, and more preferably evacuated to 10 ⁻⁷ torr or less.

  In the lamp unit 10 of the present embodiment, the cathode 21, the anode 23, and the phosphor 25, which are main components as the light source, are sealed in the internal space 10a, and the cathode 21, the anode 23, and the phosphor are sealed. 25 constitutes an FEL type light source. In the present embodiment, the cathode 21 is disposed on the one surface 17 a on the inner space 10 a side of the through hole cover 17, and the anode 23 and the phosphor 25 are opposed to the cathode 21 on the rear side plane 13 b of the convex lens 13. Is arranged. The cathode 21 and the anode 23 are disposed along the central axis Ax of the reflector 11, and are formed so that the through hole 12 is disposed between the cathode 21 and the anode 23. In the present embodiment, the wall surface 12 a of the through hole 12 is formed with respect to the central axis Ax of the reflector 11 so that the wall surface 12 a of the hole inner wall forming the through hole 12 does not enter between the cathode 21 and the anode 23. It is formed to be parallel.

  The cathode 21 has, for example, a flat plate shape, and is arranged so that the convex lens 13 side, that is, the anode side plane 21 a is substantially perpendicular to the central axis Ax of the reflector 11. On the anode-side surface 21a of the cathode 21, a cold cathode member (not shown) is disposed. This cold cathode member is composed of carbon nanotubes or the like having a nano-order fine surface structure, and emits electrons by an electric field formed near the surface of the cold cathode member. As a material constituting the cold cathode member of the cathode 21, in addition to the carbon nanotube, for example, a material having a surface shape having a fine structure with a high aspect ratio, such as a material obtained by sharpening silicon and etching. Good.

  The anode 23 is a light transmissive member having a flat plate shape, for example. The anode 23 is made of a light-transmitting substance such as ITO, and other anodes 23 may be made of, for example, a mesh made of a metal material in a mesh shape or a base material such as glass. The thing etc. which vapor-deposited are mentioned.

  A predetermined voltage is applied between the cathode 21 and the anode 23 by a power source (not shown) provided outside the vehicular lamp 1, and a first electric field is formed between the cathode 21 and the anode 23. . The first electric field acts as an electron extraction electric field for extracting electrons from the cold cathode member of the cathode 21 and an electron acceleration electric field for accelerating the electrons. Electrons drawn and accelerated from the cathode 21 are attracted to the anode 23 and collide with the phosphor 25 disposed on the anode 23.

  The phosphor 25 is made of a fluorescent material that emits light by electron collision. The fluorescent material constituting the phosphor 25 is excited when it receives a predetermined energy or more, and transitions to an excited state. When the excited fluorescent material returns to the ground state, the energy of the difference between the excited state and the ground state. Is emitted as light. In the present embodiment, the fluorescent material of the phosphor 19 is shifted to the excited state by the kinetic energy of the electrons that are inclined from the cathode 21 and incident on the phosphor 25, and emitted light is emitted when returning to the ground state. That is, in the present embodiment, the FEL type light source is configured by a configuration in which electrons are emitted from the cold cathode member of the cathode 21 and collide with the phosphor 25 to emit light.

  FIG. 3 is a cross-sectional view schematically showing a light emission pattern of the vehicular lamp 1 of the present embodiment. In FIG. 3, the flow of electrons is indicated by wavy arrows, and the light propagation direction is indicated by solid arrows. Actually, the electrons are emitted from the entire anode-side surface 21a of the cathode 21, but are schematically shown only by an arrow from the center in FIG.

  The light emitted from the phosphor 25 due to the collision of electrons is emitted isotropically regardless of the incident direction of the electrons, and a part of the light is emitted directly to the front side where the convex lens 13 is disposed, and a part of the light is emitted. The light is emitted to the rear side where the cathode 21 is disposed. The light emitted forward and incident on the convex lens 13 is emitted from the lamp unit 10 forward through the convex lens 13 while being refracted by the convex lens 13 as it is. On the other hand, the light emitted to the rear side is reflected to the convex lens 13 side by the reflecting surface 11 a of the reflector 11. The light incident on the convex lens 13 by reflection is emitted forward from the lamp unit 10 through the convex lens 13 while being refracted by the convex lens 13. Light emitted from the lamp unit 10 is irradiated forward from the vehicular lamp 1 through the cover 3.

  Thus, in the present embodiment, the reflector 11 is arranged so as to surround the side surface of the internal space 10a between the anode 23 and the cathode 21, and the light emitted to the cathode 21 side is reflected by the reflector 11 on the convex lens 13 side. It is comprised so that it may be reflected and may be irradiated ahead. That is, the reflector 11 is configured to reflect the light emitted from the phosphor 25 in the direction opposite to the light emission direction in the light emission direction. Therefore, it is possible to irradiate the light emitted from the phosphor 25 in the direction opposite to the light emission direction to the front in the light irradiation direction, and to increase the use efficiency of the emitted light.

  In the above embodiment, the shape of the reflecting surface 11a of the reflector 11 is substantially a paraboloidal shape. However, the shape is not limited to this, and the rear surface of the phosphor 25 is opposite to the light emitting direction. The shape is not particularly limited as long as the emitted light can be irradiated to the front side. Considering the reflection efficiency toward the front side, it is preferable that the inner diameter of the reflecting surface 11a of the reflector 11 is a shape that increases from the cathode 21 side toward the anode 23 side. With such a shape, light can be sent to the front side with as few reflections as possible, and the attenuation of the amount of light due to reflection can be suppressed.

  In particular, when at least a part of the shape of the reflecting surface 11a of the reflector 11 has a substantially rotational paraboloid shape (for example, when only the vertical cross-sectional shape has a substantially rotational paraboloid shape), the phosphor 25 is used. Is preferably arranged near the focal point of the paraboloid of revolution. With this configuration, the light reflected by the reflecting surface 11a can be configured to be substantially parallel to the central axis of the reflector 11, that is, the light emission direction, and light can be efficiently emitted forward. Actually, when the phosphor 25 has a certain width, the light emitting surface of the phosphor 25 becomes large with respect to the focal point, and it is difficult to make it completely parallel light, but at least part of the light is parallel light. And can contribute to an increase in light quantity and convergence of light.

  In particular, when at least a part of the shape of the reflecting surface 11a of the reflector 11 has a substantially spheroid shape (for example, when only the vertical cross-sectional shape is a substantially spheroid shape), the phosphor 25 has a spheroid shape. You may arrange | position so that it may arrange | position in the 1st focus vicinity, and the back focus of the convex lens 13 and the 2nd focus of a rotation ellipse may correspond. With this configuration, the light reflected by the reflecting surface 11a can be configured to be substantially parallel to the central axis of the reflector 11, that is, the light emission direction, and light can be efficiently emitted forward. Actually, when the phosphor 25 has a certain width, the light emitting surface of the phosphor 25 becomes large with respect to the focal point, and it is difficult to make it completely parallel light, but at least part of the light is parallel light. And can contribute to an increase in light quantity and convergence of light.

  In the above embodiment, only the cathode 21 and the anode 23 are arranged as the electrodes. However, the present invention is not limited to this, and an electron extraction electric field from the cathode 21 is formed or electrons emitted from the cathode 21 are converged. A third electrode that forms an electric field may be further disposed between the cathode 21 and the anode 23.

  For example, FIG. 4 is a diagram showing a modification of the vehicular lamp according to the present embodiment. A lamp unit 110 having a configuration in which a gate electrode 30 for electron extraction is further disposed as a third electrode in the through hole 12. It is shown.

  The gate electrode 30 is an electrode that forms an electric field for extracting electrons (second electric field) in the vicinity of the cold cathode member of the cathode 21. The gate electrode 30 is fixed on the wall surface 12 a in the through hole 12 so as to be in the vicinity of the cathode 21, and is integrated with the reflector 11 so as to close the through hole 12. Also in this modified example, the wall surface 12 a of the through hole 12 is formed with respect to the central axis Ax of the reflector 11 so that the wall surface 12 a of the hole inner wall forming the through hole 12 does not enter between the cathode 21 and the anode 23. It is formed to be parallel. The gate electrode 30 has a fine mesh structure, for example, and can pass electrons in the thickness direction of the gate electrode 30, that is, in the direction from the cathode 21 to the anode 23.

  A voltage is applied between the gate electrode 30 and the cathode 21 by a power source (not shown) provided outside the vehicular lamp 1. With this voltage, an electron extraction electric field is formed between the gate electrode 30 and the cathode 21. The electron extraction electric field extracts electrons from the cold cathode member 15 and guides the extracted electrons to the gate electrode 30 side while accelerating. The accelerated electrons pass through the gate electrode 30, and the electrons that have passed through the gate electrode 30 are guided to the anode 23 by the accelerating electric field formed between the cathode 21 and the anode 23, and collide with the phosphor 25 to emit light. To do. The light propagation pattern after light emission is the same as that described with reference to FIG.

  Thus, in this modification, since the gate electrode 30 is provided in the vicinity of the cathode 21, the extraction electric field for extracting electrons from the cathode 21 can be formed independently of the electron acceleration electric field for accelerating the electrons. Further, if the gate electrode 30 is formed integrally with the reflector 11 in advance, the number of parts is reduced in the assembly of the lamp unit, and the assembly efficiency is improved.

  In the present modification, the wall surface 12 a is parallel to the central axis Ax of the reflector 11 so that the wall surface 12 a of the through hole 12 to which the gate electrode 30 is fixed does not enter between the cathode 21 and the anode 23. It is formed as follows. Therefore, electrons drawn from the cathode 21 can be guided to the anode 23 without being inhibited by the wall surface 12a. Therefore, it is possible to improve the electron arrival rate of the electrons and thus to improve the light emission efficiency.

  In the above description, the cathode 21 and the anode 23 are arranged with the through hole 12 interposed therebetween. However, the present invention is not limited to this. For example, the cathode 21 is arranged on the reflecting surface 11a of the reflector 11. May be. Also in this case, a gate electrode 30 may be provided between the cathode 21 and the anode 23 as necessary.

In the above description, the phosphor 25 is described as being disposed on the cathode 21 side surface of the anode 23. However, the present invention is not limited to this, and before the electrons are blocked by the anode 23, the phosphor 25. For example, the phosphor 25 may be disposed on the surface opposite to the cathode 21 of the anode 23.

It is sectional drawing which shows one Embodiment of the vehicle lamp which concerns on this invention. It is sectional drawing which shows a lamp unit. It is sectional drawing which shows typically propagation of the electron and light in a lamp unit. It is sectional drawing which shows the lamp unit of the modification of the vehicle lamp which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle lamp 2 Lamp body 3 Cover 5 Aiming mechanism 10 Lamp unit 10a Internal space 11 Reflector 12 Through-hole 13 Convex lens 15 Lens holder 21 Anode 23 Cathode 25 Phosphor 30 Gate electrode

Claims (6)

An anode and a cathode spaced apart from each other to form a first electric field;
A phosphor formed on the anode and made of a fluorescent material,
A vehicle lamp that emits electrons emitted from the cathode by being accelerated toward the anode by the first electric field to excite the phosphor of the phosphor,
A vehicular lamp comprising a reflector that reflects light emitted from the phosphor in a direction opposite to a light emitting direction in the light emitting direction.   The vehicle lamp according to claim 1, wherein the reflector is disposed so as to surround a side surface of a space between the anode and the cathode.   3. The vehicular lamp according to claim 1, wherein an inner diameter of the reflector increases as it proceeds from the cathode side to the anode side.   The vehicular lamp according to any one of claims 1 to 3, further comprising a third electrode that is disposed between the anode and the cathode and that forms a second electric field. The reflector is provided between the cathode and the anode, and includes a through hole penetrating the outer surface and the inner surface of the reflector,
The vehicular lamp according to claim 4, wherein the third electrode is disposed in the through hole.   5. The vehicular lamp according to claim 4, wherein a wall surface of an inner wall of the hole forming the through hole is parallel to a straight line connecting the anode and the cathode.

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