JP2008192340A - Cold-cathode fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold-cathode fluorescent lamp with light-emitting luminance improved and light-emitting flickering of fluorescent material restrained. <P>SOLUTION: The cold-cathode fluorescent lamp is structured of a wire-like anode 16 with a fluorescent film 14 inside a vacuum-sealed lamp tube 12 arranged, and a ring-shape cathode 20 with an electric field electron emission film 18 arranged in a ring-like shape around the wire-like anode 16. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, an anode with a fluorescent film and a cathode with a field electron emission film are disposed opposite to each other in a vacuum sealed lamp tube, and electrons are emitted from the field electron emission film toward the anode by applying an electric field between these positive and negative electrodes. The present invention relates to a cold cathode fluorescent lamp that excites the phosphor to emit light by applying the electrons to the phosphor.

  In the cold cathode fluorescent lamp, an anode with a fluorescent film and a cathode with a field electron emission film are arranged opposite to each other on the inner surface of the lamp tube, and a positive DC voltage is applied to the anode to emit electrons from the field electron emission film toward the anode by field emission. The emitted electrons collide with the phosphor on the anode to cause the phosphor to excite and emit light (Patent Document 1).

In the above-mentioned cold cathode fluorescent lamp, an anode with a fluorescent film is formed on the inner surface of the lamp tube, so that the excitation light emission of the phosphor needs to be transmitted through the phosphor itself and the anode, and further through the lamp tube and emitted outside the lamp tube. And the luminance of the excitation light emission decreases. For this reason, it has been necessary to improve the transmittance of excitation light emission by using a phosphor film as a thin film, for example, by forming the phosphor particles constituting the phosphor film into several layers. For this reason, the phosphor particle density of the phosphor film is lowered, and it is difficult to sufficiently increase the excitation light emission luminance from the phosphor film. In addition, flickering is likely to occur in excitation light emission due to charge-up of electrons to the fluorescent film. This flickering of excitation light emission is caused by a so-called electron kicking phenomenon in which electrons emitted from the field electron emission film are kicked by the fluorescent film due to electron charge-up to the fluorescent film.
JP 2002-343279 A

  The problem to be solved by the present invention is to improve light emission luminance and suppress light emission flicker.

  In the cold cathode fluorescent lamp according to the present invention, a wire-like anode with a fluorescent film is disposed in a vacuum-sealed lamp tube, and a ring-like cathode with a field electron emission film comprises an inner surface of the lamp tube, a wire-like anode, The wire-like anode is arranged in a ring shape around the wire-like anode.

  In the present invention, an anode is not disposed between the cathode and the inner surface of the lamp tube, but a ring-shaped cathode is disposed between the anode and the inner surface of the lamp tube. When the fluorescent film is excited to emit light by collision of electrons, the excited light can be transmitted directly through the lamp tube. As a result, the brightness of the excited light is reduced more than when the anode or the fluorescent film needs to be transmitted. Therefore, the fluorescent film does not need to be formed into a thin film in consideration of light transmission, and can be formed into a dense film, so that the emission luminance can be increased. Further, even if there is an electron charge-up of the fluorescent film, the light emission is diffused before reaching the lamp tube from the fluorescent film, so that the light emission flicker is reduced.

  In a preferred aspect of the present invention, the lamp tube has a straight tube shape, and the wire-like anode is disposed along the tube axis direction at a substantially center in the lamp tube, and rings are provided on both ends of the wire-like anode. The cathode is arranged.

  In a preferred aspect of the present invention, the lamp tube has a straight tube shape, and the wire-like anode is disposed approximately along the tube axis in the center of the lamp tube. One ring-shaped cathode is arranged.

  In a preferred aspect of the present invention, the lamp tube has a circle shape.

  According to the present invention, it is possible to emit light uniformly by suppressing the light emission flicker of the phosphor, improve the overall luminance, and greatly increase the light emission efficiency.

  Hereinafter, a cold cathode fluorescent lamp according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a perspective view of the cold cathode fluorescent lamp of the embodiment, and FIG. 2 is a side view of the cold cathode fluorescent lamp of FIG.

  Referring to these drawings, the cold cathode fluorescent lamp 10 includes a lamp tube 12 having a straight tube shape and vacuum-sealed inside. Both ends of the lamp tube 12 in the figure are shown in an open state for convenience of illustration, and the structure of vacuum sealing is not shown in detail. The material of the lamp tube 12 may be a well-known material used for this type of lamp, and is not particularly limited. The lamp tube 12 is not limited to the size of its diameter, but its diameter is uniform in the tube axis direction and is preferably a long cylindrical shape with a circular cross section. A wire-like anode 16 with a fluorescent film 14 is disposed in the lamp tube 12. The shape and the like of the wire-like anode 16 are not particularly limited, but preferably have a circular cross section and a uniform diameter, and are arranged so as to extend in a wire shape in the tube axis direction at the center of the lamp tube 12. The ratio of the diameter and length of the lamp tube 12 to the diameter and length of the wire-like anode 16 is not particularly shown for convenience of illustration, and the embodiment is not limited to the ratio of the diameter and length shown in the drawings. .

  The fluorescent film 14 on the surface of the wire-like anode 16 is a fluorescent film that emits visible light when excited by electron beam irradiation, and is formed with a required film thickness and film density by coating or the like. The phosphor 14 may be a well-known phosphor and is not particularly limited. The phosphor 14 can be formed on the anode 16 by coating or the like by a slurry coating method, a screen printing method, an electric perturbation method, a sedimentation method, or the like. The anode 16 does not need to be made of ITO (indium oxide / tin) which is a transparent conductive film as in the prior art. Further, when the lamp tube 12 is thin, it is difficult to form the anode 16 on the wide inner surface. However, in the embodiment, there is no step of forming the anode 16 on the inner surface of the lamp tube 12, which is advantageous in terms of cost. Further, it is not always easy to form the fluorescent film 14 on the surface of the anode 16 as in the prior art. However, in the embodiment, the fluorescent film 14 is simply immersed in the fluorescent material solution on the surface of the wire-like anode 16. Since it can be formed on the surface of the wire-like anode 16, the manufacturing cost can be reduced.

  Around each end of the wire-like anode 16, a ring-like cathode 20 with a field electron emission film 18 is arranged in a ring shape. Both ring cathodes 20 are preferably substantially perfect circles and both have substantially the same diameter. The distance between the wire-shaped anode 16 and the ring-shaped cathode 20 may be set to a distance at which electrons are emitted from the field electron emission film 18 by field emission when a predetermined high DC voltage is applied between the two electrodes 16 and 20. it can. The field electron emission film 18 is composed of a carbon film made of fine protrusions on the order of nm having a large number of electron emission performances. This carbon film is composed of carbon nanotubes, carbon nanowalls, needle-like carbon films, and the like, and emits electrons due to electric field concentration at the tips of minute protrusions. The ratio of the diameter and length of the wire-like anode 16 to the diameter and size of the ring-like cathode 20 is shown for convenience of illustration, and the embodiment is not limited to the ratio shown in the figure.

  In the cold cathode fluorescent lamp 10 of the embodiment having the above-described configuration, when a DC voltage is applied between the wire-like anode 16 and the ring-like cathodes 20 from a DC power supply (not shown), the wire-like anode 16. An electric field is generated between the two ring-shaped cathodes 20 and electrons are emitted from the field electron emission film 18 of both ring-shaped cathodes 20 in the direction indicated by the arrow 22 by field emission. The emitted electrons collide with the fluorescent film 14 and the fluorescent film 14 emits excitation light as indicated by an arrow 24.

  The power supply to the wire-like anode 16 and the ring-shaped cathode 20 can be applied by connecting a DC power source between the wire-like anode 16 and the ring-shaped cathode 20 or by applying a positive electrode of a DC power source to the wire-like anode. There is a method of connecting and grounding the negative electrode of the DC power supply, while applying a high frequency between the ring-shaped cathodes 20, and the embodiment is not limited to the power supply application method.

  In the above, when the fluorescent film 14 emits excitation light by collision of electrons emitted from the field electron emission film 18 of the ring-shaped cathode 20, the excitation light emission does not pass through the fluorescent film 14 or the anode 16, but directly the lamp tube. As a result of being able to pass through 12, the excitation light emission is emitted outside the lamp tube 12 with almost no reduction in the luminance thereof, and as a result, the emission luminance becomes higher than in the prior art. Further, the fluorescent film 14 does not need to be formed into a thin film in consideration of the light transmission property when emitting the emitted light outside the lamp tube 12, and can be formed into a dense film. Therefore, the emission luminance can be increased. Further, even if the fluorescent film 14 is charged up, the light emission from the fluorescent film 14 is diffused before reaching the lamp tube 12, and thus the light emission flicker can be reduced.

  Referring to FIG. 3, a cold cathode fluorescent lamp 10a according to another embodiment will be described. In this cold cathode fluorescent lamp 10a, one ring-like cathode 20 is provided not at both ends of the wire-like anode 16 but at the central portion. ing.

  In the case of this cold cathode fluorescent lamp 10a, electrons are emitted from the ring-shaped cathode 20 in the direction indicated by the arrow 22 by application of a DC power source between the wire-shaped anode 16 and the ring-shaped cathode 20, whereby the phosphor film 14 is formed. As indicated by an arrow 24, excitation light can be emitted.

  A cold cathode fluorescent lamp 10b according to still another embodiment will be described with reference to FIG. 4. The cold cathode fluorescent lamp 10b has a circle shape, and a wire-like anode 16 has a center in the tube of the circle-shaped lamp tube 12. Are arranged in a circle. The ring-shaped cathode 20 is provided at several locations in the circumferential direction of the wire-shaped anode 16. In the case of this cold cathode fluorescent lamp 10b, electrons are emitted from the ring-shaped cathode 20 in the direction indicated by the arrow when a DC power source is applied between the wire-shaped anode 16 and the ring-shaped cathode 20, thereby exciting the phosphor film 14. Light can be emitted.

  The present invention is not limited to the above-described embodiments, and includes various changes or modifications within the scope described in the claims.

FIG. 1 is a perspective view of a cold cathode fluorescent lamp according to an embodiment of the present invention. FIG. 2 is a side view of the cold cathode fluorescent lamp of FIG. FIG. 3 is a side view of a cold cathode fluorescent lamp according to another embodiment of the present invention. FIG. 4 is a perspective view of a cold cathode fluorescent lamp according to still another embodiment of the present invention.

Explanation of symbols

10, 10a, 10b Cold cathode fluorescent lamp 12 Lamp tube 14 Fluorescent film 16 Wire-shaped anode 18 Field electron emission film 20 Ring-shaped cathode

Claims (4)

  A wire-like anode with a fluorescent film is arranged in a vacuum-sealed lamp tube, and one or more ring-like cathodes with a field electron emission film are arranged around the wire-like anode. Features a cold cathode fluorescent lamp.   The lamp tube has a straight tube shape, and the wire-like anode is arranged in a wire shape along the tube axis direction at a substantially center in the lamp tube, and ring-like cathodes are arranged on both ends of the wire-like anode. The cold cathode fluorescent lamp according to claim 1, wherein:   The lamp tube is a straight tube, and the wire-like anode is arranged in a wire shape along the tube axis direction in the center of the lamp tube, and one ring-like cathode is provided at the substantially center side of the wire-like anode. The cold cathode fluorescent lamp according to claim 1, wherein the cold cathode fluorescent lamp is arranged.   The lamp tube has a circle shape, and the wire-shaped anode is arranged in a wire shape along the tube axis direction at a substantially center in the lamp tube, and a plurality of ring-shaped cathodes are arranged around the wire-shaped anode in several places. The cold cathode fluorescent lamp according to claim 1, wherein the cold cathode fluorescent lamp is arranged.

Images