JP4249740B2 - Luminance recovery method and apparatus for cold cathode tube - Google Patents

Description

The present invention relates to a method and an apparatus for recovering the brightness of a cold cathode tube using a discharge in mercury vapor.

Cold cathode tubes are widely used as light sources for LCD modules, for example, taking advantage of their small size and long life (for example, Patent Document 1). Although the cold cathode fluorescent lamp has a long life, the luminance decreases as the lighting time elapses. Therefore, an old cold cathode tube having a luminance below a certain level was replaced with a new one, and the old cold cathode tube was discarded.

JP-A-11-149905

  However, there is a case where the cold cathode tube cannot be replaced due to out of stock of new products or discontinuation of production, which causes great inconvenience to the user. In particular, in the case of discontinuation of production, products using the cold cathode tubes must be discarded. Also, with the recent increase in interest in environmental conservation, it has become a problem to dispose of cold cathode tubes containing harmful mercury easily. For this reason, there is an increasing potential demand for reuse of cold cathode fluorescent lamps, but no effective countermeasure has been found at present.

An object of the present invention can realize reuse of the cold cathode tube is to provide a luminance recovery method and apparatus of the cold cathode tube.

The present inventor has obtained the following knowledge as a result of repeated studies to achieve the above object. The main reason for the brightness of the cold cathode tube is lowered, the mercury should be vapor in the cold cathode tube is to liquefy some reason. If the cold cathode tube is heated until the liquefied mercury is vaporized again, the luminance is restored. The present invention has been made based on this finding.

That is, the luminance recovery method according to the present invention is a method for recovering the luminance of a cold cathode tube using discharge in mercury vapor, and heating the cold cathode tube until liquefied mercury is vaporized. Features .

Mercury in the cold cathode tube begins to liquefy part in the course of operation, the steam which contributes mercury emission decreases with this, the luminance decreases. Here, when the cold cathode tube is heated until the liquefied mercury is vaporized again, the vaporized mercury maintains the vapor state without returning to the liquid even when the cold cathode tube is cooled. Therefore, the brightness of the cold cathode fluorescent lamp can be restored to a new value. In this way, an old cold cathode tube can be regenerated as a new one with a simple method of “heating the cold cathode tube ”, so that it can meet the user's repair request regardless of whether the cold cathode tube is out of stock or discontinued. become able to. In addition, since the cold cathode tubes can be reused, the number of discarded cold cathode tubes is reduced.

The cold cathode tube may be heated by leaving the cold cathode tube in a constant temperature bath set at a constant temperature for a certain period of time . It is a thermostat which is also where the equipment, since it is only necessary to leave the cold cathode tube in a constant temperature bath, can be heated very briefly CCFL.

By heating by the induction heating device a heating element in contact with or close to the cold cathode tube, heating the cold-cathode tube may be. The heating element is a conductor or a ferromagnetic material. At this time, the heating element is a ferromagnetic foil winding a cold-induction heating device has an air core coil for generating a high-frequency magnetic field, an empty cold cathode tubes wound on a ferromagnetic foil It is good also as inserting in a core coil . The ferromagnetic material generates heat not only due to eddy current but also due to hysteresis loss, so that heat can be generated efficiently.

The cold cathode tube does not break the filament like the hot cathode tube due to its electrode structure. Therefore, the life of the cold cathode tube is mainly determined by a decrease in luminance. Therefore, by recovering the luminance of the cold cathode tubes, the number of discarded cold cathode tubes can be greatly reduced, so that the effect of the present invention is most remarkable. In addition, the cold cathode tube in this invention contains all what light-emits using the discharge in the vapor | steam of mercury, and is not limited to a cold cathode tube or a hot cathode tube.

Cold luminance recovery device according to the present invention is a device for restoring the brightness of the cold cathode tube using a discharge in mercury vapor, and heating means for heating the cold cathode tube, which is heated by the heating means energizing means for lighting the cold cathode tube by energizing the cathode tube, a brightness measuring means for measuring the luminance of the cold cathode tube which is energized by the energizing means, the heating means based on the luminance measured by the luminance measuring means And a control means for controlling . At this time, the control unit has a function of stopping the heating of the cold cathode tube by the heating unit when the luminance measured by the luminance measuring unit becomes a certain level or more . According to the luminance recovery device of the present invention, it is possible to automatically recover a cold cathode tube having reduced luminance to a certain luminance.

According to the present invention, by an extremely simple method of simply heating the cold-cathode tube, it is possible to restore the brightness of the old cold-cathode tube, it is possible to realize a re-use of the cold cathode tube. Therefore, it is possible to respond to the user's repair request regardless of whether the cold cathode tube is out of stock or discontinued, and the service to the user can be improved. Moreover, the reuse of the cold cathode tube, it is possible to reduce the cold-cathode tube to be discarded, along with can be effectively utilize resources, it can contribute significantly to environmental protection.

  FIG. 1 is a conceptual diagram showing a first embodiment of a luminance recovery method according to the present invention. Hereinafter, description will be given based on this drawing.

  First, a terminal monitor 1 having an LCD display failure such as a dark display screen or no display screen is prepared. Then, the terminal monitor 1 is disassembled to take out the LCD module 2, and the LCD module 2 is disassembled to take out the cold cathode tube 5 of the backlight.

  Subsequently, the covered lead wire 3 connected to the cold cathode tube 5 is removed together with the connector 4. The remaining cold-cathode tube 5 is placed in a thermostat 6 and heated for a certain time. After the elapse of time, the coated lead wire 3 is reconnected to the cold cathode tube 5 and incorporated into the LCD module 2 to be modularized again.

  Finally, after confirming that the brightness of the display screen of the LCD module 2 has been restored, the LCD module 2 is incorporated into the terminal monitor 1. As a result, the terminal monitor 1 can be used again.

  2 to 4 are cross-sectional views showing the cold cathode tube 5. Hereinafter, the light emission principle, light emission attenuation and luminance recovery of the cold cathode tube 5 will be described with reference to these drawings.

  The light emission principle will be described with reference to FIG. The inner wall surface of the glass tube 7 of the cold cathode tube 5 is thinly coated with a phosphor 8 serving as a light emitter. Inside the glass tube 7, gaseous mercury 9 and an inert gas 10 made of argon and neon are enclosed. Electron emission electrodes 11 made of molybdenum or tungsten are provided at both ends of the glass tube 7. Electric power is supplied to the electron emission electrode 11 from the outside of the glass tube 7 by the external electrode 12.

When an alternating electric field of about 1 kV and 50 kHz generated by an inverter (external power supply circuit) (not shown) is applied to the external electrode 12, electrons 13 are generated from the electron emission electrode 11 by this electric field. That is, by entering a discharge state, electrons 13 collide with gaseous mercury 9 floating in glass tube 7, and ultraviolet rays 14 are emitted from mercury 9. When the ultraviolet rays 14 give the phosphor 8 energy necessary for light emission, the phosphor 8 is excited to emit light. In general, the light emission principle of a cold cathode tube is the same for home use and industrial use.

  The light emission attenuation will be described with reference to FIG. The gaseous mercury 9 contained in the glass tube 7 gradually becomes liquid mercury 15 by lighting for a long time. Possible causes of liquefaction include dust emitted from the electron emission electrode 11, partial temperature drop along the tube wall of the glass tube 7, and deviation of the alternating electric field waveform of the inverter. As a result, since the ultraviolet rays 14 are reduced with the reduction of the gaseous mercury 9, the life symptoms are finally reached.

  The luminance recovery will be described based on FIG. The liquefied mercury 15 can be returned to gaseous mercury 9 by heating from the outside. Once the mercury 9 returned to the gaseous state was cooled, it did not become liquid, and it was confirmed that the brightness could be restored.

  FIG. 5 is a graph showing the relationship between the heating temperature and time for the cold cathode tube 5 and the luminance increase rate. Hereinafter, a description will be given based on FIGS. 1 and 5.

  As shown in FIG. 1, the cold cathode tube 5 was placed in the thermostat 6 and the heating temperature and time were changed. As a result, an increase in luminance was confirmed as shown in FIG. 5. In FIG. 5, this increase in luminance is expressed as a ratio from the non-light emitting state to the new initial luminance. It was also confirmed that the heating temperature was optimal for 20 to 30 minutes in the vicinity of 356.58 ° C., which is the boiling point of mercury. That is, the brightness of the cold cathode tube 5 can be effectively recovered by leaving the cold cathode tube 5 in the thermostat 6 set to 350 ± 20 ° C. for 20 minutes or more and 30 minutes or less. However, it was found that it was not possible to restore the initial brightness of the new product. This is because the light transmittance of the cold cathode fluorescent lamp 5 is reduced because the glass tube is discolored by ultraviolet rays.

  FIG. 6 is a conceptual diagram showing a second embodiment of the luminance recovery method according to the present invention. Hereinafter, description will be given based on this drawing.

  In the present embodiment, the cold cathode tube 5 which has reached the luminance life is wound with the ferromagnetic foil 20, and these are placed in a coiled high frequency ring cylinder 17 (that is, an air-core coil). Is energized by a high frequency power source 18 to locally heat the cold cathode tube 5. That is, the high frequency ring cylinder 17 and the high frequency power supply 18 constitute an induction heating device.

  First, a terminal monitor 1 having an LCD display failure such as a dark display screen or no display screen is prepared. Then, the terminal monitor 1 is disassembled to take out the LCD module 2, and the LCD module 2 is disassembled to take out the cold cathode tube 5 of the backlight.

  Subsequently, a ferromagnetic foil (foil) 20 made of iron, nickel, cobalt or the like is wound so as to wrap the cold cathode tube 5. As a commercial product of the ferromagnetic foil 20, a pyrofoil manufactured by Dainippon Ink and Chemicals, Inc. was used.

  Subsequently, the cold cathode tube 5 in a state where the ferromagnetic foil 20 is wound is placed in the high frequency ring cylinder 17 and induction heating is performed. The heating element is a ferromagnetic foil 20. At this time, the cold-cathode tube 5 is connected to the inverter 19 and turned on. Since the ferromagnetic foil 20 is generated not only by eddy current but also by hysteresis loss, it can efficiently generate heat. In addition, since the mercury in the cold cathode tube 5 to be heated is a very small amount, no eddy current is generated, so that it does not generate heat by itself.

  The high frequency power supply 18 is set to an output of 30 kW and 80 kHz. By passing a current through the high-frequency ring cylinder 17, the ferromagnetic foil 20 rises to 350 ° C. in 2 to 3 seconds and starts to heat the cold cathode tube 5. In this state, high-frequency output is stopped at a point where an arbitrary increase in luminance is observed while observing an increase in luminance at the end of the cold-cathode tube 5 with a color luminance meter (not shown).

  Thereafter, the cold cathode tube 5 is incorporated into the LCD module 2 to be modularized again. Finally, after confirming that the brightness of the display screen of the LCD module 2 has been restored, the LCD module 2 is incorporated into the terminal monitor 1. As a result, the terminal monitor 1 can be used again.

  Instead of the ferromagnetic foil 20, a conductor foil may be used. In this case, heat is generated only by eddy current.

  FIG. 7 [1] is a block diagram showing an embodiment of a luminance recovery apparatus according to the present invention. Hereinafter, description will be given based on this drawing.

  As shown in FIG. 7 [1], the luminance recovery device 100 of the present embodiment energizes the cold cathode tube 5 heated by the heating unit 101 and the heating unit 101 that heats the cold cathode tube 5 whose luminance has decreased. In this way, the current-carrying means 102 for turning on the cold-cathode tube 5, the brightness measuring means 103 for measuring the brightness of the cold-cathode tube 5 energized by the current-carrying means 102, and heating based on the brightness measured by the brightness measuring means 103 And a control means 104 for controlling the means 101.

  The heating means 101 is, for example, the above-described constant temperature bath or induction heating device. The energizing means 102 is a power source that supplies electric power necessary for lighting the cold cathode tube 5. The luminance measuring means 103 is composed of, for example, a lens, a filter, a photodetector, etc., and outputs an electrical signal corresponding to the received luminance. The control means 104 is composed of, for example, a microcomputer and its program, and receives luminance data from the luminance measuring means 103 and outputs control signals to the heating means 101, the energizing means 102 and the luminance measuring means 103 based on the data. .

  FIG. 7 [2] is a flowchart showing the operation of the luminance recovery apparatus 100. Hereinafter, a description will be given based on FIGS. 7 [1] and [2].

  The cold cathode tube 5 is positioned in advance so that the wiring from the energizing means 12 is connected to the cold cathode tube 5 so that it can be heated by the heating means 101 and measured by the luminance measuring means 103. Subsequently, the control means 104 starts to operate as follows. First, heating, energization, and measurement are started (step 201). Then, for each sampling time, it is determined whether or not the luminance has reached a certain level (step 202). If the brightness is below a certain level, continue heating, energization, and measurement. On the other hand, if the luminance is above a certain level, the luminance of the cold-cathode tube 5 has been recovered, and heating / energization / measurement is stopped (step 203). According to the luminance recovery device 100, the cold cathode fluorescent lamp 5 whose luminance has decreased can be automatically recovered to a certain luminance.

  Although not shown, if the luminance is less than a certain value even after a certain period of time, an error signal is output and heating / energization / measurement is stopped. Or you may make it raise heating temperature and to continue heating, electricity supply, and a measurement. The control unit 104 only needs to have a function of stopping the heating of the cold cathode tube 5 by the heating unit 101 when the luminance measured by the luminance measurement unit 103 becomes equal to or higher than a certain level. You may make it leave the control with respect to 103 to another means.

  Needless to say, the present invention is not limited to the above embodiments. For example, the present invention can be applied to a household fluorescent lamp or a high-intensity mercury lamp instead of a cold cathode tube.

It is a conceptual diagram which shows 1st embodiment of the brightness | luminance recovery method which concerns on this invention. It is sectional drawing of the cold cathode tube which shows the light emission principle. It is sectional drawing of the cold cathode tube which shows light emission attenuation | damping. It is sectional drawing of the cold cathode tube which shows brightness | luminance recovery. It is a graph which shows the relationship between the heating temperature and time about a cold cathode tube, and a luminance increase rate. It is a conceptual diagram which shows 2nd embodiment of the brightness | luminance recovery method which concerns on this invention. FIG. 7 [1] is a block diagram showing a configuration, and FIG. 7 [2] is a flowchart showing an operation, showing an embodiment of a luminance recovery device according to the present invention.

Explanation of symbols

5 Cold cathode tube 6 Thermostatic bath 7 Glass tube 8 Phosphor 9 Mercury (vapor)
10 Inert Gas 11 Electron Emission Electrode 12 External Electrode 13 Electron 14 Ultraviolet 15 Mercury (Liquid)
17 High-frequency ring cylinder (air-core coil)
18 High frequency power supply (part of induction heating device)
DESCRIPTION OF SYMBOLS 20 Ferromagnetic foil 100 Luminance recovery apparatus 101 Heating means 102 Current supply means 103 Luminance measuring means 104 Control means

Claims (2)

Heating the cold cathode tube,
The cold cathode tube is turned on by energizing the heated cold cathode tube,
Measure the brightness of the cold cathode tube that is energized,
When the measured luminance is above a certain level, the heating of the cold cathode tube is stopped.
A method for recovering the brightness of a cold cathode tube .
Heating means for heating the cold cathode tubes ;
Energizing means for lighting the cold cathode tube by energizing the cold cathode tube heated by the heating means;
A luminance measuring means for measuring the luminance of the cold cathode tube that is energized by the energizing means;
Control means for controlling the heating means based on the brightness measured by the brightness measuring means ,
This control means has a function of stopping the heating of the cold cathode tube by the heating means when the brightness measured by the brightness measuring means becomes a certain level or more.
A brightness recovery device for a cold cathode tube .

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