JP2007265900A - Lighting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve light emitting efficiency by accelerating heat discharging effect in a lighting apparatus. <P>SOLUTION: The temperature of a tube wall in a glass tube of the lighting apparatus can be lowered by having the heat generated in an electrode 3 inside a cold-cathode fluorescent lamp 2 spread to a terminal for power supply 5 since the terminal for power supply 5 which is connected to a lead line for power supply 4 is brought into contact with an exterior wall of the glass tube in the position facing the electrode 3 of the cold-cathode fluorescent lamp 2. Furthermore, by installing the terminal for power supply 5 so that it is also brought into contact with a housing, since the heat spread to the terminal for power supply is discharged outside through the housing of the apparatus, the environmental temperature inside the apparatus can be lowered. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lighting device, and more particularly to a direct lighting device used as a backlight of a large monitor such as a liquid crystal TV.

  In general, the backlight of a large monitor such as a liquid crystal TV is easy to increase the brightness. Therefore, a phosphor film is formed on the inner wall of the glass tube, and one or more kinds of rare gases and mercury are enclosed inside the glass tube. A direct-type illumination device using a cold cathode fluorescent lamp (also called CCFL) as a light source is used.

  As shown in the assembly perspective view of FIG. 5, the conventional direct illumination device 1 includes a reflector 101 laid on the bottom surface of the back frame 100, and a plurality of cold cathode fluorescent lamps 202 serving as light emitting surfaces inside the back frame 100. Are arranged in parallel. On the upper surface, a diffusion plate 102, a lens sheet 103a, a lens sheet 103b, and a diffusion sheet 104 for reducing luminance unevenness are sequentially stacked and stored in the front frame 105. An inverter 10 is installed on the back side of the back frame 100.

FIG. 6 shows a cross-section of the CC ′ portion of the illumination device 1 shown in FIG. As shown in the figure, in the cold cathode fluorescent lamp 202 fixed by the lamp holding hook 208, the electrodes 203 are arranged at both ends inside the glass tube, and the power supply lead wire 204 connected to the electrode 203 is connected to the outside of the glass tube. It is extended to. The power supply lead wire 204 is connected to a harness wire 205 for conducting power supply from the inverter 10 by soldering. Here, in order to protect the soldering portion 206 to which a high voltage is applied, it is covered with a rubber holder 207 (see, for example, Patent Document 1 and Patent Document 2). In the conventional lighting device having such a configuration, heat generated by the electrode 203 inside the cold cathode fluorescent lamp 202 due to light emission is dissipated by the harness electric wire 205.
JP-A-8-171144 JP-A-8-172508

  However, since the harness wire is covered and the core wire diameter is thin, the conventional lighting device has a problem that heat radiation becomes insufficient, the ambient temperature inside the device rises, and the luminous efficiency of the lamp decreases.

  This invention is made | formed in view of the above, and makes it a subject to promote the thermal radiation effect in an illuminating device and to improve luminous efficiency.

  In the lighting device according to the present invention, a phosphor film is formed on the inner wall of a glass tube, one or more kinds of rare gases and mercury are enclosed in the glass tube, and electrodes are disposed at both ends of the glass tube. The power supply lead wire connected to is connected to the cold cathode fluorescent lamp extended to the outside of the glass tube and the power supply lead wire, and contacts the outer wall of the glass tube at a position corresponding to the electrode. And a power feeding terminal arranged.

  In the present invention, the power supply terminal connected to the power supply lead wire is arranged so as to contact the outer wall of the glass tube at a position corresponding to the electrode of the cold cathode fluorescent lamp, so that the inside of the cold cathode fluorescent lamp is arranged. Since the heat generated at the electrode propagates to the power supply terminal, the tube wall temperature of the glass tube can be lowered.

  The power supply terminal in the lighting device is arranged so as to contact the housing of the device.

  In the present invention, by arranging the power feeding terminal so as to also contact the housing of the apparatus, the heat propagated to the power feeding terminal is dissipated to the outside through the housing of the apparatus. The atmospheric temperature can be lowered.

  The power supply terminal in the illumination device is arranged such that a portion of the glass tube that contacts the outer wall of the glass tube does not exceed the center side of the position corresponding to the tip of the cold cathode fluorescent lamp on the center side. .

  In the present invention, the portion where the power feeding terminal contacts the outer wall of the glass tube is disposed so as not to cross the center side of the electrode corresponding to the tip of the cold cathode fluorescent lamp at the center side, Originally, the discharge that should occur between the electrodes inside the cold cathode fluorescent lamp is surely generated from the tip of the electrode without accidentally occurring at the power supply terminal outside the cold cathode fluorescent lamp, causing lighting failure and discharge delay It is possible to prevent erroneous discharge.

  The lighting device is characterized in that a heat conductive member is disposed between the power feeding terminal and the outer wall of the glass tube.

  In the present invention, by disposing a heat conductive member between the outer wall contact portion of the power feeding terminal and the outer wall of the glass tube, the heat radiation effect by the power feeding terminal is maintained and the external shock and vibration are applied. The load on the cold cathode fluorescent lamp can be reduced.

  The illumination device further includes a lamp holding means that is provided in contact with the outer wall of the glass tube at a position away from the front end of the cold cathode fluorescent lamp at the center side of the electrode and holds the cold cathode fluorescent lamp. And

  In the present invention, the lamp holding means is provided in contact with the tube wall of the glass tube corresponding to the position away from the tip of the cold cathode fluorescent lamp central side of the electrode toward the central side, thereby providing the inside of the cold cathode fluorescent lamp. Since the heat generated in this is also propagated to the lamp holding means, the tube wall temperature in this portion is lowered, and mercury can be kept at the center side inside the glass tube. Thereby, it is possible to prevent the mercury concentration from being biased to the vicinity of the electrode due to the heat dissipation effect by the power supply terminal, and to efficiently consume the mercury.

  According to the present invention, the heat dissipation effect in the lighting device is promoted, and the light emission efficiency can be improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking as an example a direct illumination device used as a backlight of a large monitor of a liquid crystal TV.

  FIG. 1 is an assembled perspective view schematically showing the overall structure of a lighting apparatus according to an embodiment. As shown in the figure, in the lighting device 1, a reflector 101 is laid on the bottom surface of the back frame 100, and a plurality of cold cathode fluorescent lamps 2 are arranged in parallel as light emitting surfaces inside the back frame 100. On the upper surface, a diffusion plate 102, a lens sheet 103a, a lens sheet 103b, and a diffusion sheet 104 for reducing luminance unevenness are sequentially stacked and stored in the front frame 105. An inverter 10 that supplies an operating voltage to the cold cathode fluorescent lamp 2 is installed on the back side of the back frame 100.

  FIG. 2 shows a cross section of the A-A ′ portion shown in the illumination device 1 of FIG. 1. As shown in the figure, the lighting device 1 includes a cold cathode fluorescent lamp 2 and a power feeding terminal 5 connected to an output terminal of an inverter 10 in a back frame 100 in which a reflector 101 is laid on the bottom surface. And a lamp holding hook 6 for holding the cold cathode fluorescent lamp 2.

  In the cold cathode fluorescent lamp 2, a phosphor film 11 is formed on the inner wall of the glass tube, one or more kinds of rare gases and mercury are sealed inside the glass tube, and electrodes 3 are arranged at both ends inside the glass tube. A power supply lead wire 4 connected to the electrode 3 extends to the outside of the glass tube. Here, neon Ne, a rare gas of argon Ar, and mercury Hg are sealed inside a glass tube having a length of about 738 mm, and columnar electrodes 3 are arranged at both ends.

  The power supply terminal 5 is connected to the power supply lead wire 4 and arranged to contact the outer wall of the glass tube at a position corresponding to the electrode 3. Here, it arrange | positions so that the part which contacts the outer wall of a glass tube may not cross the center side rather than the position corresponding to the front-end | tip part of the cold cathode fluorescent lamp center side of the electrode 3. FIG. Furthermore, the power feeding terminal 5 is disposed so as to contact the back frame 100 which is a housing of the apparatus via the reflection plate 101. As the material for the power supply terminal 5, iron, copper, nickel plating or the like having high thermal conductivity is used.

  A heat conductive member 7 is disposed between the power supply terminal 5 and the outer wall of the glass tube. Here, as the heat conductive member 7, a sheet-like heat conductive sheet made mainly of heat conductive silicon is used.

  The structure of the power supply terminal 5 will be described more specifically. FIG. 3 is a perspective view showing the tip of the cold cathode fluorescent lamp 2. As shown in the figure, the power supply terminal 5 is in contact with the lead wire connecting portion 5a connected to the power supply lead wire 4, the outer wall contact portion 5b contacting the outer wall of the glass tube, and the housing of the apparatus. It is comprised with the housing | casing contact part 5c arrange | positioned.

  The lead wire connecting portion 5a is a slit portion in which a part of the end side is cut out at one end portion in the longitudinal direction of a rectangular thin copper plate. Here, the lead wire connecting portion 5a is connected to the power feeding lead wire 4 by pressure contact.

  The outer wall contact portion 5b is a top surface of a pedestal formed by bending the other end portion in the long side direction of the rectangle with respect to a direction parallel to the short side direction of the rectangle. Here, the outer wall contact portion 5b is brought into contact with the outer wall of the glass tube at a position corresponding to the electrode 3 through a heat conductive sheet laid on the surface, and a position corresponding to the tip portion of the electrode 3 on the center side of the cold cathode fluorescent lamp. It arrange | positions so that it may not cross to the center side.

  The housing contact portion 5c is a rectangular central surface. Here, the housing contact portion 5 c is disposed so as to contact the reflecting plate 101 inside the back frame 100.

  With this configuration, in the lighting device 1, the operating voltage from the inverter 10 is supplied to the electrodes 3 disposed at both ends inside the cold cathode fluorescent lamp 2 through the power supply terminal 5. When a high voltage is applied between the electrodes 3, electrons existing in the tube are attracted and collide with the electrode 3 at a high speed, secondary electrons are emitted, and discharge is generated from the tips of both electrodes 3. Due to this discharge, electrons attracted by the anode collide with mercury molecules in the tube, and ultraviolet rays (wavelength 253.7 nm) are emitted to the phosphor coating 11. The ultraviolet rays excite the phosphor to generate visible light, and the cold cathode fluorescent lamp 2 emits light.

  Since the heat generated at the electrode 3 inside the cold cathode fluorescent lamp 2 due to light emission propagates from the outer wall contact portion 5b to the power feeding terminal 5, the tube wall temperature of the glass tube can be lowered. Since the heat transmitted to the power supply terminal 5 is radiated to the outside from the housing contact portion 5c through the housing of the device, the ambient temperature inside the device can be lowered. In this way, the heat dissipation effect in the lighting device is promoted, and the light emission efficiency can be improved.

  In addition, the outer wall contact portion 5b that contacts the outer wall of the glass tube is disposed so as not to cross the center side of the electrode 3 from the position corresponding to the tip of the cold cathode fluorescent lamp at the center side. The discharge to be generated between the electrodes 3 inside the fluorescent lamp 2 is surely generated from the tip of the electrode 3 without being erroneously generated at the power supply terminal 5 outside the cold cathode fluorescent lamp 2. Thereby, it is possible to prevent erroneous discharge that causes lighting failure and discharge delay.

  Further, since the heat conductive member 7 is disposed between the power supply terminal 5 and the outer wall of the glass tube, the heat dissipation effect by the power supply terminal 5 is maintained, and cold cathode fluorescence caused by external shock and vibration is maintained. The load on the lamp can be reduced.

  On the other hand, since the mercury particles inside the cold cathode fluorescent lamp 2 gather at a point where the temperature is low at the time of light emission, the mercury concentration is biased to the vicinity of the electrode due to the heat dissipation effect by the power supply terminal 5. Therefore, in the present embodiment, as shown in the plan view of the cold cathode fluorescent lamp of FIG. 4, the lamp holding hook 6 is placed at the glass tube at a position away from the tip of the cold cathode fluorescent lamp at the center side of the electrode 3 toward the center side. It is provided so as to come into contact with the outer wall. Here, the lamp holding hook 6 is made of a material having high thermal conductivity such as thermoplastic resin or silicon rubber, and a glass tube at a position 50 mm away from the tip of the cold cathode fluorescent lamp center side of the electrode 3 to the center side. It is provided so as to contact the outer wall.

  With such a configuration, the heat generated inside the cold cathode fluorescent lamp 2 is also propagated to the lamp holding hook 6, so that the temperature of the glass wall of this portion of the glass tube is lowered, and the center of the inside of the glass tube is lowered. Mercury can be retained. Thereby, it is possible to prevent the mercury concentration from being biased to the vicinity of the electrode due to the heat radiation effect by the power supply terminal 5 and to efficiently consume the mercury.

  Therefore, according to the present embodiment, the power supply terminal 5 connected to the power supply lead wire 4 is disposed so as to contact the outer wall of the glass tube at a position corresponding to the electrode 3 of the cold cathode fluorescent lamp 2. Since the heat generated at the electrode 3 inside the cold cathode fluorescent lamp 2 propagates to the power feeding terminal 5, the tube wall temperature of the glass tube can be lowered. Further, by disposing the power supply terminal 5 so as to be in contact with the housing of the apparatus, the heat transmitted to the power supply terminal 5 is radiated to the outside through the housing of the apparatus. Can be reduced. Thereby, the heat dissipation effect in the lighting device is promoted, and the light emission efficiency is improved.

  In addition, the portion where the power supply terminal is in contact with the outer wall of the glass tube is disposed so as not to cross the center side of the position corresponding to the tip of the cold cathode fluorescent lamp at the center side of the electrode. The discharge that should occur between the electrodes inside the lamp is surely generated from the tip of the electrode without accidentally occurring at the power supply terminal outside the cold cathode fluorescent lamp. Can be prevented.

  Furthermore, by disposing a heat conductive member between the power supply terminal and the outer wall of the glass tube, while maintaining the heat dissipation effect by the power supply terminal 5, the load on the cold cathode fluorescent lamp due to external impact and vibration is reduced. Can be reduced.

  On the other hand, by providing a lamp holding means in contact with the tube wall of the glass tube corresponding to a position away from the tip of the cold cathode fluorescent lamp center side of the electrode toward the center side, the heat generated inside the cold cathode fluorescent lamp is reduced. Since it propagates to the lamp holding means, the temperature of the tube wall in this portion is lowered, and mercury can be retained at the center side inside the glass tube. Thereby, it is possible to prevent the mercury concentration from being biased to the vicinity of the electrode due to the heat dissipation effect by the power supply terminal, and to efficiently consume the mercury.

  In the present embodiment, the lamp holding hook 6 is provided so as to contact the outer wall of the glass tube at a position 50 mm away from the tip of the electrode 3 on the cold cathode fluorescent lamp center side. However, the present invention is not limited to this, and the electrode 3 may be provided at a position away from the tip of the cold cathode fluorescent lamp center side to the center side in the range of 15 mm to 50 mm. Even in such a configuration, the tube wall temperature of the glass tube is lowered by the heat dissipation effect of the lamp holding hook 6, so that mercury can be kept at the center side inside the glass tube, which is equivalent to the present embodiment. Can produce various effects.

  Further, in the present embodiment, a sheet-like thermally conductive sheet mainly composed of thermally conductive silicon is disposed as a thermally conductive member between the power supply terminal 5 and the outer wall of the glass tube. However, the present invention is not limited to this, and a heat conductive rubber may be disposed. Even in this case, it is possible to reduce the load on the cold cathode fluorescent lamp due to external impact and vibration while maintaining the heat dissipation effect by the power supply terminal.

  In the present embodiment, the lead wire connecting portion of the power feeding terminal and the power feeding lead wire are connected by pressure contact, but the present invention is not limited to this, and the lead wire connecting portion of the power feeding terminal is connected by soldering. It is good also as a structure which connects with the lead wire for electric power feeding.

It is the assembly perspective view which showed roughly the whole structure of the illuminating device which concerns on one embodiment. It is sectional drawing which showed the cross section of the A-A 'part shown with the illuminating device of FIG. It is the perspective view which showed the front-end | tip part of the cold cathode fluorescent lamp in the said illuminating device. It is a top view of the cold cathode fluorescent lamp when the illuminating device of FIG. 1 is seen from the arrow B direction. It is the assembly perspective view which showed roughly the whole structure of the conventional illuminating device. It is sectional drawing which showed the cross section of the C-C 'part of the illuminating device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Illuminating device 2 ... Cold cathode fluorescent lamp 3 ... Electrode 4 ... Feeding lead wire 5 ... Feeding terminal 5a ... Lead wire connection part 5b ... Outer wall contact part 5c ... Housing contact part 6 ... Lamp holding hook 7 ... Heat conduction 10 ... Inverter 11 ... Phosphor coating 100 ... Back frame 101 ... Reflector plate 102 ... Diffuser plate 103a, 103b ... Lens sheet 104 ... Diffusion sheet 105 ... Front frame 202 ... Cold cathode fluorescent lamp 203 ... Electrode 204 ... Lead for power supply Wire 205 ... Harness wire 206 ... Soldering part 207 ... Rubber holder 208 ... Lamp holding hook

Claims (5)

A phosphor coating is formed on the inner wall of the glass tube, one or more kinds of rare gases and mercury are enclosed in the glass tube, electrodes are arranged at both ends of the glass tube, and a power feed lead connected to the electrode A cold cathode fluorescent lamp in which a wire is extended to the outside of the glass tube;
A power supply terminal connected to the power supply lead wire and arranged to contact the outer wall of the glass tube at a position corresponding to the electrode,
A lighting device comprising:   The lighting device according to claim 1, wherein the power feeding terminal is disposed so as to contact a housing of the device. The power feeding terminal is
The part which contacts the outer wall of the said glass tube is arrange | positioned so that it may not exceed the said center side rather than the position corresponding to the front-end | tip part of the cold cathode fluorescent lamp center side of the said electrode. The lighting device described.   The lighting device according to any one of claims 1 to 3, wherein a heat conductive member is disposed between the power feeding terminal and an outer wall of the glass tube. The lamp further comprises lamp holding means for holding the cold cathode fluorescent lamp provided in contact with the outer wall of the glass tube at a position away from the front end of the cold cathode fluorescent lamp on the center side of the electrode. The lighting device according to claim 1.

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