JP2005235649A - Cold cathode fluorescent lamp and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the startability of starting electric discharge without deterioration of luminance. <P>SOLUTION: In a cold cathode fluorescent lamp including a glass valve 1, phosphor coat 2 formed on an inner surface of the glass valve 1, noble gas and mercury enclosed in the glass valve 1, and electrodes 3 and 3' connected to a pair of leading-in conductor attached in a sealed condition to both ends of the valve 1, a spatter layer 15 is formed on an inner surface of the phosphor coat 2 near the periphery of one of the electrodes 3 by supplying dc voltage for aging. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cold cathode fluorescent lamp used as a light source for a liquid crystal display device or the like and a method for manufacturing the same.

  As shown in FIG. 4, the basic structure of the cold cathode fluorescent lamp is that a phosphor coating 2 is formed on the inner surface of a straight tube-type glass bulb 1, and rare gas and mercury are hermetically sealed inside the glass bulb 1. In this configuration, a pair of electrodes 3 and 3 ′ are arranged at both ends of the glass bulb 1. Lead electrodes 4 and 4 ′ are connected to the electrodes 3 and 3 ′, respectively, and by supplying power to the electrodes 3 and 3 ′ via the lead wires 4 and 4 ′, the cold cathode fluorescent lamp discharges. Start.

  By the way, if the cold cathode fluorescent lamp is left in a dark or low temperature environment for a long time, the start of discharge is delayed because the number of initial electrons that trigger the discharge has decreased. It becomes. In order to prevent this, in the cold cathode fluorescent lamp shown in FIG. 4, the electrodes 3, 3 ′ are sputtered by passing an overcurrent during aging or extending the aging time. Sputtered layers 5 and 5 ′ are formed on the inner surface of the phosphor coating 2 in the vicinity of 3 ′.

As a measure for improving the startability at the start of discharge, an electron radioactive substance such as a Cs compound is applied to the inner periphery of the end of the electrode or glass bulb as a discharge delay countermeasure material layer (see Patent Documents 1 to 3). Alternatively, alumina is included in the phosphor coating.
Japanese Patent Laid-Open No. 9-326246 JP 2001-15065 A Japanese Patent No. 3164876

  A measure to improve the startability of the discharge start by forming the sputtered layer shown in FIG. 4 (hereinafter referred to as “forced blackening” as appropriate) is the aging of 8 to 12 mA by alternating current for forming the sputtered layer. Although it is necessary to pass an electric current for about 2 hours, there exists a problem that lamp brightness falls by this electricity supply. Specifically, as shown in the graph showing the change in relative luminance with respect to the aging time in the case of the aging current of 10 mA in FIG. 5, the total luminous flux with respect to the initial value after the aging time of 2 hours is reduced by about 3%.

  Similarly, a measure for containing alumina in the phosphor coating is that the discharge delay time increases as the alumina content increases, as shown in the graph showing the relationship of the discharge delay time to the alumina content in FIG. Although shortening, when 10% or more of alumina that achieves the discharge delay time of 100 msec or less, which is the target of the countermeasure, is included, there is a problem that the total luminous flux is reduced by 4% or more as shown in FIG.

  On the other hand, there are other measures to apply the electron radioactive substance, such as an increase in the application process, and the electron radioactive substance scattered from the inner wall surface of the electrode or the glass bulb during lighting, resulting in flickering of the light emitted from the cold cathode fluorescent lamp. There's a problem.

  The present invention has been made in view of the above, and it is an object of the present invention to provide a cold cathode fluorescent lamp and a method for manufacturing the same that accurately improve the startability of the discharge start without lowering the luminance.

  In order to achieve the above object, the present invention according to claim 1 includes a glass bulb, a phosphor coating formed on the inner surface of the glass bulb, a rare gas and mercury sealed in the glass bulb, In a cold cathode fluorescent lamp comprising electrodes connected to a pair of lead wires sealed at both ends of the glass bulb, a DC voltage is fed to the inner surface of the phosphor coating in the vicinity of one electrode. The gist is to have a sputtered layer formed by aging.

  According to a second aspect of the present invention, there is provided a glass bulb, a phosphor film formed on the inner surface of the glass bulb, a rare gas and mercury enclosed in the glass bulb, and both end portions of the glass bulb. In a cold cathode fluorescent lamp having an electrode connected to a pair of lead wires sealed to each other, sputtering is performed on the inner surface of the phosphor coating in the vicinity of one electrode by performing aging by feeding a DC voltage. The gist is to form a layer.

  In the present invention, a large number of spatters are formed in a short time by aging by feeding a DC voltage, so that it is necessary to improve the startability of the discharge start while preventing a decrease in the total luminous flux due to long-term aging. A sputter layer is reliably formed.

  According to the present invention, it is possible to shorten the aging time and prevent a decrease in luminance as compared with the conventional case, and it is possible to form a necessary sputter layer and improve the startability of the discharge start. In addition, since the sputtered layer is formed only in the vicinity of one periphery of the electrode, the ineffective light emitting portion due to the presence of the sputtered layer is at least halved as compared with the conventional case where the sputtered layer is formed in the vicinity of both the periphery of the electrode. be able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a cross-sectional configuration of a cold cathode fluorescent lamp according to an embodiment of the present invention. This cold cathode fluorescent lamp is substantially the same as that shown in FIG. 4 as an example of the conventional structure. A fluorescent coating 2 is formed on the inner surface of the glass bulb 1, and argon, neon, At least one kind of rare gas such as xenon and mercury are sealed, and electrodes 3 and 3 'are sealed at both ends of the glass bulb 1, respectively. And, in order to apply a voltage to each electrode 3, 3 ′, one end of introduction lines 4, 4 ′ is connected to each other, and the other end of the introduction lines 4, 4 ′ penetrates the end wall of the glass bulb 1 in an airtight manner And it is derived outside.

  As a feature of the present embodiment, the sputter layer 15 is formed on the inner surface of the phosphor coating 2 in the vicinity of one electrode 3 by aging by feeding a DC voltage.

  In the embodiment shown in FIG. 1, the phosphor coating 2 is 15 to 25 μm on a glass bulb 1 made of soda glass, borosilicate glass or the like having an outer diameter of 3.0 mm and an axial length of about 500 mm. It is applied.

  In the cold cathode fluorescent lamp having the above-described configuration, the electrode 3 on which the sputter layer 15 is formed is used as an anode, and the lamp is turned on by applying a required inverter voltage. Due to the presence of the sputtered layer 15, the start of discharge is not delayed even when left in a dark or low temperature for a long time.

  2 and 3 are diagrams showing a comparison of discharge delay time and brightness between the cold cathode fluorescent lamp aged with a direct current of 18 mA in this embodiment and the cold cathode fluorescent lamp with a conventional countermeasure. As is clear from both figures, the only thing that can satisfy the target of the discharge delay time of 100 msec is the one applied with the present embodiment and the electron-emitting material. Although a decrease was observed in the case where the electron-emitting material was applied, no decrease was observed in the present embodiment. That is, in the cold cathode fluorescent lamp according to the present embodiment, the startability at the start of discharge is improved without causing a decrease in luminance.

1 is a cross-sectional view of a cold cathode fluorescent lamp according to an embodiment of the present invention. The graph which compared the discharge delay time of said embodiment with the thing of a prior art example. The graph which compared the brightness of said embodiment with the thing of a prior art example. Sectional drawing of the cold cathode fluorescent lamp of a prior art example. The figure which shows the change of the relative total light flux with respect to the lighting time of a cold cathode fluorescent lamp. The figure which shows the relationship of the discharge delay time with respect to the content rate of the alumina in a fluorescent substance film. The figure which shows the change of the relative total light flux with respect to the content rate of the alumina in a fluorescent substance film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass bulb 2 ... Phosphor film 3, 3 '... Electrode 4, 4' ... Lead-in wire 15 ... Sputtering layer

Claims (2)

A glass bulb, a phosphor coating formed on the inner surface of the glass bulb, a rare gas and mercury sealed inside the glass bulb, and a pair of lead wires sealed at both ends of the glass bulb, respectively In a cold cathode fluorescent lamp comprising connected electrodes,
A cold-cathode fluorescent lamp comprising a sputter layer formed by aging by feeding a DC voltage on the inner surface of a phosphor coating in the vicinity of one electrode. A glass bulb, a phosphor coating formed on the inner surface of the glass bulb, a rare gas and mercury sealed inside the glass bulb, and a pair of lead wires sealed at both ends of the glass bulb, respectively In a cold cathode fluorescent lamp comprising connected electrodes,
A method of manufacturing a cold cathode fluorescent lamp, wherein a sputtering layer is formed on the inner surface of a phosphor coating near the periphery of one electrode by performing aging by feeding a DC voltage.

Images