JP2005174751A - Method of manufacturing fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a fluorescent lamp for easily forming a uniform and appropriate phosphor layer while taking advantage of a merit of suction-applying method. <P>SOLUTION: In the method of manufacturing the fluorescent lamp having a step of forming a phosphor layer 2' by suction-applying phosphor slurry 2 containing thermosetting binder on an inner wall surface of a translucent bulb 1, the phosphor slurry 2 is heated from the side of the peripheral surface after sucking the phosphor slurry 2 in the translucent bulb 1 and the phosphor slurry 2 on the side of the inner wall surface in the translucent bulb 1 is cured to form a cured layer 2'. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a fluorescent lamp, and more particularly to a method for manufacturing a thin tube type or long fluorescent lamp suitable for a backlight of a liquid crystal display device of a liquid crystal display or an instrument display panel.

  As is well known, fluorescent lamps are generally manufactured by the following means. For example, a slurry containing phosphor particles (powder) is flow-coated on the inner wall surface of a light-transmitting bulb such as a glass tube, dried, baked and baked, then placed on the discharge electrode, evacuated, sealed with a discharge medium, and vacuum The required fluorescent lamp is manufactured through processes such as sealing of the exhaust pipe and mounting of the base terminal. In some cases, at least one of the discharge electrodes may be installed on the outer peripheral surface of the translucent bulb.

  In the fluorescent lamp manufacturing method, as described above, a slurry containing phosphor particles (powder) is applied to the inner wall surface of the light-transmitting bulb by flow coating and coating, a slurry collecting step after coating, and coating by spraying dry air. A series of manufacturing operations such as a membrane drying process is regarded as important. That is, it is desired to reduce the diameter of a fluorescent lamp as a backlight light source as the size of the liquid crystal device is reduced, and to increase the diameter and length of the liquid crystal device as the size of the liquid crystal device increases. On the other hand, from the viewpoint of improving the quality of the fluorescent lamp, it is desirable that the thickness of the phosphor layer is uniform throughout.

  However, in the case of the above-described flow coating method, even if a phosphor slurry having a uniform composition system is prepared, it is difficult to completely avoid coating unevenness. In view of such circumstances, a coating method has been developed in which the phosphor slurry is sucked into the light-transmitting bulb and applied instead of the phosphor slurry applied by flow coating.

  Once the phosphor slurry is sucked into the light-transmitting bulb, the sucked phosphor slurry is allowed to flow down and dried by blowing dry air or hot air onto the phosphor slurry layer remaining on the inner wall surface of the light-transmitting bulb. The means for forming a film is regarded as effective in the manufacture of a fluorescent lamp. That is, by adjusting the viscosity of the phosphor slurry and adjusting the flow rate of dry air, it is possible to coat the phosphor slurry without unevenness and to form a phosphor layer with a uniform thickness.

  However, it cannot be said that it is a sufficient means for the demand for a fluorescent lamp having a narrow tube (thin diameter) or a long tube. In other words, it is difficult to adjust the viscosity of the phosphor slurry and the flow rate of dry air, etc. to form a phosphor layer with a substantially uniform thickness, or to form a phosphor layer with an appropriate thickness. The narrowing and lengthening of fluorescent lamps are also limited. Furthermore, when the light-transmitting bulb is reduced in diameter or lengthened, dry air is blown onto the phosphor slurry layer remaining on the inner wall surface of the light-transmitting bulb to form a phosphor layer with an appropriate thickness. There is an inconvenience that it is difficult to form and that uneven application of the phosphor slurry is likely to occur. In other words, it is difficult to obtain a high-quality thin tube type or long type fluorescent lamp at all times, and it is in a situation where it cannot sufficiently meet the requirements.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a method of manufacturing a fluorescent lamp that can easily form a uniform and appropriate phosphor layer while taking advantage of the suction coating method.

The invention of claim 1 is a method of manufacturing a fluorescent lamp comprising a step of sucking and applying a phosphor slurry containing a thermosetting binder to an inner wall surface of a translucent bulb to form a phosphor layer,
In the fluorescent lamp manufacturing method, the phosphor slurry is sucked into the translucent bulb and then heated from the outer peripheral surface side to form a cured layer of the phosphor slurry on the inner wall surface side of the translucent bulb.

  According to a second aspect of the present invention, in the method for manufacturing a fluorescent lamp according to the first aspect, the thermosetting binder has light transmittance.

  In the invention of claim 1 or 2, the translucent bulb is, for example, a glass tube, a quartz glass tube, or a translucent alumina tube, and the outer diameter (or inner diameter), length, and shape of the translucent bulb. In particular, it is not limited. For example, a curved pipe such as a straight pipe shape or a U-shape may be used.

  According to the first and second aspects of the present invention, the phosphor constituting the main component of the phosphor slurry includes a general halophosphate system, a red light emitting phosphor such as europium activated yttrium oxide, and terbium activated lanthanum phosphate. -Green light-emitting phosphors such as cerium, blue light-emitting phosphors such as divalent europium activated barium aluminate and magnesium, and three-wavelength light-emitting phosphors that are a mixture of these rare earth phosphors. The phosphor slurry is prepared by a general method, and a composition system containing a thermosetting binder as one component is adopted.

  Here, examples of the thermosetting binder include acrylic or phenolic thermosetting resins, and more preferably translucent formaldehyde-free acrylic thermosetting resins, and these thermosetting binder components. The composition ratio is not particularly limited, but is generally about 5 to 10% by weight. The viscosity or fluidity and curability of the phosphor slurry are important factors. For example, the viscosity is generally about 30 to 40 Cp (room temperature), and the curability is not fast. preferable.

In the invention according to claim 1 or 2, the suction application of the phosphor slurry to the inner wall surface of the light-transmitting bulb is performed by, for example, immersing one end opening of the light-transmitting bulb in the phosphor slurry and connecting the other end opening to the decompression system. Then, it is carried out by means of sucking (sucking) into the translucent bulb. And, in order to perform the heat treatment of the next step while the phosphor slurry is sucked into the translucent bulb, it is necessary to suck and hold the phosphor slurry.
In the first and second aspects of the invention, the heating means for heating the translucent bulb from the outer peripheral surface in a state where the phosphor slurry is sucked up, brings the entire outer peripheral surface of the translucent bulb to a substantially uniform temperature. It must be possible to raise the temperature. That is, in order to form a phosphor layer having a uniform film thickness by thermosetting the phosphor slurry in the translucent bulb from the inner wall surface side at a uniform speed as a whole, the outer circumferential surface of the translucent bulb Requires a heating function to raise the temperature to a substantially uniform temperature as a whole.

  In order to meet such demands, for example, a cylindrical heating device that inserts a translucent bulb in the length direction, a constant temperature chamber heating device that can insert and mount a plurality of translucent bulbs upright, and the like are used. And the hardening layer of the phosphor slurry on the inner wall surface side of the translucent bulb, in other words, the phosphor layer thickness control / adjustment, the type and composition ratio of the thermosetting binder, the heating temperature, the heating rate of heating, etc. Is done according to. When the phosphor slurry is turned into a cured layer having a required layer thickness on the inner wall surface side of the translucent bulb, the vacuum suction to the phosphor slurry is released, and the remaining uncured phosphor slurry flows down and is collected.

  In the inventions of claims 1 and 2, by controlling the heating temperature or heating conditions of the outer peripheral surface of the light-transmitting bulb, even if it is a thin tube or a long light-transmitting bulb, there is no application unevenness on the inner wall surface. A phosphor layer having a substantially uniform thickness can be formed. That is, it is possible to provide a high-quality fluorescent lamp that exhibits a uniform light distribution over the entire length suitable for a backlight light source or the like of a liquid crystal device.

  According to the present invention, even if a thin tube or a long light-transmitting bulb is controlled by controlling the heating temperature or heating conditions of the outer peripheral surface of the light-transmitting bulb, it is substantially uniform without causing uneven coating on the inner wall surface. A phosphor layer with a sufficient thickness can be formed. Therefore, it is possible to mass-produce a high-quality fluorescent lamp that exhibits a uniform light distribution over the entire length suitable for a light source for a backlight of a liquid crystal device.

  The embodiment will be described below with reference to FIGS. 1 (a), (b), (c) and (d).

  1 (a), (b), (c) and (d) are cross sections schematically showing an embodiment in which phosphor slurry is sucked and applied to the inner wall surface of a glass bulb, and a phosphor layer is formed by heat curing. FIG. That is, one end of a glass bulb 1 having a tube diameter of 3.0 mm and a length of 300 mm is immersed in the phosphor slurry, the other end is connected to a vacuum decompression system, and the phosphor slurry 2 is sucked into the glass bulb 1. Fill as shown in FIG. Here, the phosphor slurry 2 has a viscosity of 35 Cp and contains about 5% by weight of a thermosetting binder.

  Next, as shown in FIG. 1B, a concentric cylindrical heating device 3 is mounted on the glass tube 1 sucked and filled with the phosphor slurry 2, and the outer peripheral surface side of the glass tube 1 is placed. Heat. That is, in consideration of physical properties such as viscosity and curability of the phosphor slurry, the thickness of the phosphor layer to be formed, etc., the heating operation is performed under the temperature / temperature raising conditions selected and set. Here, the mounting arrangement of the cylindrical heating device 3 may be arranged in advance prior to the suction filling of the phosphor slurry 2, and the cylindrical heating device 3 is configured to be openable and closable along the axis. May be good.

  By heating from the outer peripheral surface side of the glass bulb 1, the phosphor slurry 2 in the glass bulb 1 is gradually cured from the inner wall surface side of the glass bulb 1 as shown in FIG. Turn into That is, the cured layer 2 ′ having a substantially uniform thickness can be arbitrarily formed according to the composition adjustment of the phosphor slurry, the type and amount of the thermosetting binder, the heating conditions, and the like. After forming the cured layer 2 'of the phosphor slurry 2, when the vacuum suction system is opened and the uncured phosphor slurry 2 is taken out (flowing down), as shown in FIG. A glass bulb having the layer 2 'on the inner wall surface is obtained.

  Here, the fact that the phosphor can be applied and formed to a required thickness without any unevenness on the inner wall surface of a glass bulb having a tube diameter of about 1.8 to 5.0 mm easily and with a good yield is a uniform light distribution over the entire length. A fluorescent lamp can be provided. In other words, since the light emission luminance in the bulb axial direction is uniform, it is possible to provide a mass production method of a high-quality fluorescent lamp that uniformly irradiates light in the entire axial direction.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention.

(A), (b), (c), (d) is sectional drawing which shows the principal part of an embodiment example typically in order of a process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass tube 2 ... Phosphor slurry 2 '... Phosphor slurry hardening layer 3 ... Heating apparatus

Claims (2)

A method of manufacturing a fluorescent lamp comprising a step of forming a phosphor layer by sucking and applying a phosphor slurry containing a thermosetting binder on the inner wall surface of a light-transmitting bulb,
A method of manufacturing a fluorescent lamp, comprising sucking up the phosphor slurry into a light-transmitting bulb and then heating from the outer peripheral surface to form a hardened layer of the phosphor slurry on the inner wall surface side of the light-transmitting bulb.   2. The method of manufacturing a fluorescent lamp according to claim 1, wherein the thermosetting binder has light transmittance.

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