JP2008010169A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device capable of irradiating light of a phosphor highly efficiently from a field emission lamp. <P>SOLUTION: The lighting device is provided with a field emission lamp 4 and a reflecting sheet (reflection member) 18 which is installed at the rear part of the field emission lamp 4 and reflects to the front emitted light from the rear side of the field emission lamp 4. The field emission lamp 4 has a wire-shape cathode 22 with a field electron emitting site on the surface arranged at the tube center of a cylindrical lamp tube 20, and has an anode 24 with a phosphor installed at the semi-circle portion 20a on front side of the lamp tube 20, and the semi-circle portion 20b on rear side is made transparent so as to transmit the emitted light of the phosphor 24b as an emission light toward the reflecting sheet 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an illumination device using a field emission lamp.

  In the prior art, there has already been proposed one in which a reflector is installed behind the illumination lamp and the emitted light from the rear side of the illumination lamp is reflected forward (see Patent Documents 1 and 2). These reflectors are formed in a shape that repeatedly bends corresponding to a plurality of illumination lamps arranged side by side. However, in the prior art, the reflector is simply disposed behind the illumination lamp without considering the internal structure of the illumination lamp.

  Of the illumination lamps, field emission lamps have a wire-like cathode with a field electron emission site on the surface in the center of a cylindrical tube with a vacuum inside, and fluorescent light is applied to the entire inner surface of the vacuum tube. By providing an anode with a body and applying an electric field between the positive and negative electrodes, electrons are emitted from the field electron emission site on the cathode surface toward the anode, and the emitted electrons collide with the phosphor to excite the phosphor. There is something to make.

Such a field emission lamp is in a vacuum state in which no discharge gas is contained inside due to field electron emission, and the excitation light emission of the phosphor is directly emitted to the outside as emitted light. And since the anode with a phosphor is provided in a planar shape around the inner surface of the lamp tube, the emission of the phosphor is absorbed and attenuated around the entire lamp tube in the process of passing through the anode from the inside of the phosphor. For this reason, even if not only the forward emitted light but also the backward emitted light is reflected forward by the reflector, the light emission amount is considerably reduced.
JP 2005-267852 A JP 2002-156512 A

  Therefore, the problem to be solved by the present invention is to enable emission of the phosphor from the field emission lamp with high efficiency.

  An illumination device according to a first aspect of the present invention includes a field emission lamp, and a reflection member that is installed behind the field emission lamp and reflects light emitted from the rear side of the field emission lamp forward. However, a wire-like cathode having a field electron emission site on the surface is arranged at the center of the tube of the cylindrical lamp tube, and an anode with a phosphor is provided on the inner surface of the front side portion of the lamp tube. The portion is transparent in order to transmit light emitted from the phosphor toward the reflecting plate as outgoing light.

  In the first aspect of the present invention, the light emitted from the phosphor passes through the inside of the anode with the phosphor and emits the light emitted directly from the phosphor through the transparent portion of the lamp tube, in addition to the forward emitted light that is emitted forward to the outside. The backward emitted light exits the transparent lamp tube portion without being attenuated by the phosphor-attached anode, and can be reflected by the reflecting plate. As compared with the case where an anode with a phosphor is provided, the overall light emission luminance can be improved greatly and efficiently.

  According to a first preferred aspect of the present invention, the wire-like cathode has a field electron emission site in a surface region facing the inner surface of the front side portion of the lamp tube, and in a surface region facing the inner surface of the rear side portion. Preferably does not have a field electron emission site.

  In this embodiment, when field electron emission sites are provided around the entire circumference of the wire-like cathode (first case), the phosphors collide with the phosphor out of all the electrons emitted from the entire circumference and cause the phosphor to excite and emit light. When a field electron emission site is provided in the surface area facing the inner surface of the front portion of the lamp tube in the ratio of electrons (second case), it collides with the phosphor out of all electrons emitted from the surface area. When the ratio of electrons that excite and emit the phosphor is compared, the ratio in the second case is higher. As a result of the second case being smaller than the first case with respect to the applied power necessary for exciting and emitting the phosphor with the same luminance, the effect of reducing the power is extremely large.

  An illuminating device according to a second aspect of the present invention includes a field emission lamp, and a reflection member that is installed behind the field emission lamp and reflects light emitted from the rear side of the field emission lamp forward. However, by arranging a wire-like cathode having a field electron emission site on the surface in the center of the cylindrical lamp tube, and providing an anode with a phosphor on the inner surface of the rear side portion of the lamp tube, The light emission is transmitted rearward, and the front side portion is transparent to transmit the light emission of the phosphor.

  In the second aspect of the present invention, the light emitted from the phosphor passes through the inside of the anode with the phosphor, is emitted rearwardly outside, and is reflected by the reflecting member. And the front emission light that passes through the transparent lamp tube portion without being attenuated by the phosphor-attached anode, so that the entire circumference of the inner surface of the lamp tube can be obtained. Compared with the case where an anode with a phosphor is provided, the overall light emission luminance can be greatly improved.

  According to a second preferred embodiment of the present invention, the wire-shaped cathode has a field electron emission site in a surface region facing the inner surface of the rear side portion of the lamp tube, and in a surface region facing the inner surface of the front side portion. Preferably does not have a field electron emission site.

  In this embodiment, when field electron emission sites are provided on the entire circumference of the wire-like cathode (first case), all the electrons emitted from the entire circumference collide with the phosphor and cause the phosphor to excite and emit light. When a field electron emission site is provided in the surface region facing the inner surface of the rear portion of the lamp tube in the ratio of electrons (second case), it collides with the phosphor out of all the electrons emitted from the surface region. When the ratio of electrons that excite and emit the phosphor is compared, the ratio in the second case is higher. And in order to make a fluorescent substance light-emit with the same brightness | luminance, the electric power required for making it emit electrons in the 2nd case needs to be smaller than the 1st case, and the effect of electric power reduction is large.

  In the first and second aspects of the present invention, the meaning that the lamp tube portion is transparent does not mean that the lamp tube portion is completely transparent, but includes transparent or translucent. It is comprised from the material with higher light transmittance than. For example, the lamp tube is made of glass.

  In the first and second aspects of the invention, the front side portion of the lamp tube is a portion of the outer peripheral surface of the lamp tube where mainly forward emitted light is directly emitted forward, and the rear side portion of the lamp tube is mainly This is the portion where the backward emission light is emitted directly to the rear.

  In the first and second aspects of the present invention, the reflecting member may be formed of a member provided in a part of a housing that houses the field emission lamp, or may be formed of a reflecting plate separate from the housing.

  In the first and second embodiments of the present invention, the reflecting member is preferably a reflecting structure having a concave portion at the rear position of the field emission lamp, but the present invention is not limited to this. Moreover, although the cross-sectional shape of this recessed part is not limited, a bent shape, a curved shape, etc. can be included.

  In the first and second aspects of the present invention, the ratio of the front side portion and the rear side portion in the circumferential direction of the lamp tube can be arbitrarily controlled. For example, the front side portion and the rear side portion can be divided into half circumferences.

In the first and second aspects of the present invention, the anode is a transparent electrode such as ITO (indium oxide / tin oxide), IZO (indium oxide / zinc oxide), ZnO, SnO ₂ or an alloy thereof, and the anode is provided on the inner surface of the lamp tube. A phosphor can be provided on the anode. Moreover, it can be set as the metal back structure which provided the fluorescent substance in the lamp tube inner surface, and provided aluminum on the fluorescent substance.

  In the first and second aspects of the present invention, the front side portion and the rear side portion of the lamp tube are substantially half circumferential portions in the circumferential direction. In such a case, the light emission of the phosphor can be efficiently emitted forward and backward.

  In the first and second aspects of the present invention, the field electron emission site is constituted by a carbon film having a number of nm-sized sharp ends. In such a case, it is preferable that the light emission of the phosphor can be efficiently emitted to the outside as emitted light and the characteristics of the field emission lamp capable of emitting electrons from the field electron emission site with a low electric field are not impaired.

  According to the present invention, it is possible to emit light from a phosphor with high efficiency from a field emission lamp.

  Hereinafter, a lighting device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

(Embodiment 1)
1 shows an external configuration of the lighting apparatus according to Embodiment 1, FIG. 2 shows a cross-sectional configuration along the line AA in FIG. 1, and FIG. 3 shows a cross-sectional configuration along the line BB in FIG. 4 (a) and 4 (b) show the configuration of the main part for explaining the operation. Referring to these drawings, this illuminating device 2 has a plurality of field emission lamps 4 and a lamp storage case 6 for storing the plurality of field emission lamps 4 in an array state parallel to each other and at a constant interval. Yes. The lamp housing case 6 can be formed of synthetic resin. The storage housing 6 includes side walls 10 and 12 that rise vertically from the front, rear, left, and right of the outer periphery of the bottom wall 8. The pair of side walls 12 opposed in the longitudinal direction has a structure for supporting both ends of the field emission lamp on the inner surface thereof as a lamp holder, and applies a power supply voltage from the lighting power supply voltage source 14 to the field emission lamp inside the structure. Wiring is laid.

  The bottom wall 8 of the storage housing 6 constitutes a reflection structure that reflects backward emitted light from the rear (back) of the field emission lamp 4 to the front. This reflection structure is configured such that a bent recess 16 is formed in parallel corresponding to the rear (back) position of each field emission lamp 4. These bent recesses 16 extend in the longitudinal direction of the field emission lamp 4. A reflective sheet 18 made of white resin is laid on the surface of the bent recess 16.

  The shape of the bent recess 16 is not a bent shape but may be other shapes such as a circular arc shape in cross section. The bent concave portion 16 can be made of a resin having light reflectivity directly without providing the reflection sheet 18. Further, the reflecting structure can include a configuration in which a plurality of reflecting plates with recesses are provided on the bottom wall 8.

  In the field emission lamp 4, a wire-like cathode 22 having a large number of field electron emission sites on the surface is arranged at the center of a cylindrical tube 20 whose inside is vacuum-tight. In this wire-like cathode 22, a carbon film 22b is formed as a field electron emission site on the surface of the conductor wire 22a. The carbon film 22b is not particularly limited as long as it is a carbon film having a large number of nm-sized sharp edges that emit field electrons. For example, the outer diameter of the carbon film decreases toward the carbon nanotube, the carbon nanowall, and the tip. An acicular carbon film etc. can be illustrated. The conductor wire 22a is a solid or hollow wire. The conductor wire 22a can be entirely composed of a conductive metal, but is not limited thereto, and may be configured such that the inside is an insulating member and a conductive member is provided on the surface thereof.

  The field emission lamp 4 is provided with a phosphor-attached anode 24 in which an anode 24a and a phosphor 24b are laminated on the inner surface of a front half-circumferential portion 20a that is approximately half the circumference of the lamp tube 20, and the remaining half of the circumference in the circumferential direction. The rear half-circumference portion 20b is not provided with the phosphor-attached anode 24, but is left as a transparent portion having a light-transmitting property of the lamp tube 20.

  On the other hand, the wire-like cathode 22 is provided with a carbon film 22b as a field electron emission site in a half surface area facing the inner surface of the front half part 20a of the lamp tube 20 in the whole circumference area, and a rear half part 20b. No carbon film 22b is provided in the remaining surface half-circumferential region facing the inner surface.

  As shown in FIG. 4A, the field emission lamp 4 having the above-described configuration is applied from the surface of the wire-like cathode 22 by applying a DC voltage between the anode 24 with phosphor and the wire-like cathode 22. Electrons are emitted as a field electron emission site from a large number of carbon films 22b extending in the shape of sharp needles with a diameter of nm, and the emitted electrons collide with the phosphor 24b so that the phosphor 24b emits light by excitation. It has become.

  In this case, the carbon film 22b as a field electron emission site has a surface half circumference facing the front half circumference portion 20a of the inner surface of the glass tube 20 in which the phosphor-attached anode 24 is formed in the whole circumference region of the wire cathode 22. Since it is formed only in the region, electron emission is emitted only from the carbon film 22b formed in the half-surface region of the surface as shown by the arrow P, and collides with the phosphor 24b to cause the phosphor 24b to emit light. Can do. Further, since the carbon film 22b is not formed in the remaining half-surface region of the wire-like cathode 22 that does not face the phosphor 24b, even if the carbon film is formed in that region and electron emission is performed, Since it cannot reach the phosphor 24b and collide with it, it is not wasted, and power efficiency is improved.

  Further, in the illumination device of the first embodiment, as shown in FIG. 4B, the anode with a phosphor 24 is provided on the inner surface of the front half-circumferential portion 20a of the lamp tube 20, and the rear half-circumference of the lamp tube 20 is performed. Since the light is not provided on the inner surface of the portion 20b, the light emitted from the phosphor 24b is transmitted not only to the front emitted light Q that passes through the inside of the anode 24 with the phosphor and exits to the outside front, but also to the front emitted light B. Thus, there is rear emission light R that does not pass through the inside of the anode 24 with phosphor but directly emits light from the phosphor 24b through the rear half-circumferential portion 20b of the lamp tube 20 and exits to the outside. In this case, in the first embodiment, the anode 24 with the phosphor is not provided on the entire inner surface of the lamp tube 20, so that the backward emitted light R is not attenuated by the anode 24 with the phosphor and is a transparent lamp. Since it can pass through the tube rear-side semicircular portion 20b and be reflected by the reflection sheet 18, the overall light emission luminance is greatly improved as compared with the case where the anode 24 with phosphor is provided on the entire inner surface of the lamp tube 20. Will be able to.

(Embodiment 2)
A lighting apparatus according to Embodiment 2 of the present invention will be described with reference to FIGS. 5 and 6. FIG. 5 shows a cross-sectional configuration of the illumination device, and FIG. 6 shows a main configuration of the illumination device for explaining its operation. The illumination device 2 according to the second embodiment includes a field emission lamp 4 and a storage housing 6. The reflective structure of the storage housing 6 is the same as that of the first embodiment.

  In the second embodiment, the relationship of the field emission lamp 4 to the reflecting structure is opposite to that in the first embodiment.

  In the following, in the second embodiment, on the inner surface of the lamp tube 20 of the field emission lamp 4, the phosphor-attached anode 24 is provided on the inner surface of the rear half peripheral portion 20b, while on the inner surface of the front half peripheral portion 20a. The wire-like cathode 22 is not provided, and includes a carbon film 22b as a field electron emission site in a surface half-circumferential region facing the inner surface of the rear-side semicircular portion 20b of the lamp tube 20 in the entire peripheral region, The carbon film 22b is not provided in the surface semicircular region facing the inner surface of the semicircular portion 20a.

  In the illuminating device of the embodiment, as shown in FIG. 6A, a carbon film on the surface of the wire-like cathode 22 is applied by applying a DC voltage between the anode 24 with phosphor and the wire-like cathode 22. Electrons are emitted from a number of sharp ends having a size of 22 nm, and the emitted electrons collide with the phosphor 24b, whereby the phosphor 24b can be excited to emit light. In this case, since the carbon film 22b as the field electron emission site is formed only in the surface half circumference region of the wire-like cathode 22 facing the inner surface of the glass tube 4 on which the phosphor-attached anode 24 is formed, the electron emission is It is emitted only from the carbon film 22b formed in the semicircular region of the surface as shown by an arrow P1, and can collide with the phosphor 24b to excite the phosphor 24b, and the carbon film 22b can emit the phosphor 24b. Since it is not formed in the remaining half-surface region of the wire-like cathode 22 that is not opposed to the cathode, electron emission is not wasted and power efficiency is improved.

  In the lighting device of the second embodiment, the anode 24 with the phosphor is provided on the inner surface of the rear portion of the lamp tube 4 so that the light emitted from the phosphor 24b is transmitted rearward, and the front portion is the above-described portion. Since the structure is transparent in order to transmit the light emitted from the phosphor 24b, the front emission light Q1 emits the light emitted from the phosphor 24b directly to the outside front as shown in FIG. 6B. In addition, although the backward emission light R1 is attenuated by the anode 24 with the phosphor, it can be reflected forward by the reflection sheet 18 after passing through the lamp tube portion 20b. Compared with the case where the body-attached anode 24 is provided, the light emission luminance as a whole can be greatly improved.

FIG. 1 is a perspective view showing an external appearance of a lighting apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 3 is a cross-sectional view taken along line BB in FIG. FIG. 4A is a diagram showing an electron emission state from the field electron emission site of the wire-like cathode in the configuration of the main part of the illumination device of the first embodiment, and FIG. It is a figure which shows front emitted light and back emitted light in a part structure. FIG. 5 is a cross-sectional view corresponding to FIG. 2, which relates to a lighting apparatus according to Embodiment 2 of the present invention. FIG. 6A is a diagram showing an electron emission state from the field electron emission site of the wire-like cathode in the configuration of the main part of the illumination device of the second embodiment, and FIG. 6B is the main component of the illumination device of the second embodiment. It is a figure which shows front emitted light and back emitted light in a part structure.

Explanation of symbols

2 Lighting device 4 Field emission lamp 6 Storage case 16 Bent recess 18 Reflective sheet 20 Lamp tube 20a Front half circumference portion 20b Rear half circumference portion 22 Wire-like cathode 22a Conductor wire 22b Carbon film (field electron emission site)
24 Anode with phosphor 24a Anode 24b Phosphor P, P1 Electron emission Q, Q1 Front emission light R, R1 Rear emission light

Claims (6)

Field emission lamps,
A reflection member installed behind the field emission lamp and reflecting the emitted light from the rear side of the field emission lamp forward;
With
The above field emission lamp
A wire-like cathode having a field electron emission site on its surface at the center of a cylindrical lamp tube; and
An anode with a phosphor is provided on the inner surface of the front side portion of the lamp tube, and the rear side portion is transparent in order to transmit light emitted from the phosphor toward the reflecting plate as outgoing light. A lighting device.   The wire cathode has a field electron emission site in a surface region facing the inner surface of the front side portion of the lamp tube, and has no field electron emission site in a surface region facing the inner surface of the rear side portion. The lighting device according to claim 1. Field emission lamps,
A reflection member installed behind the field emission lamp and reflecting the emitted light from the rear side of the field emission lamp forward;
With
The above field emission lamp
A wire-like cathode having a field electron emission site on its surface at the center of a cylindrical lamp tube; and
An anode with a phosphor is provided on the inner surface of the rear side portion of the lamp tube so that the light emitted from the phosphor is transmitted rearward, and the front side portion is transparent to transmit the light emitted from the phosphor. A lighting device characterized by that.   The wire cathode has a field electron emission site in a surface region facing the inner surface of the rear portion of the lamp tube, and no field electron emission site in a surface region facing the inner surface of the front portion. The lighting device according to claim 3.   The lighting device according to any one of claims 1 to 4, wherein a front side portion and a rear side portion of the lamp tube are substantially half-circumferential portions in the circumferential direction of the lamp tube.   6. The illumination device according to claim 1, wherein the field electron emission site is configured by a carbon film having a number of nm-sized sharp ends.

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