JPH0282406A - Luminaire - Google Patents

Abstract

PURPOSE:To prevent temperature at a lamp and inside a casing from rising up by providing the casing made of metal, and heat-conductively connecting a heat conductive member surrounding an electric discharge lamp to the casing. CONSTITUTION:During lighting of a lamp, electrodes 9a and 9b generate heat, and valve walls therearound is heated. Since both ends of a valve 6 are covered with cylindrical metal caps 10a and 10b having excellent heat conductivity and surrounding the electrodes 9a and 9b, the heat radiated from the electrodes 9d and 9b is concentrated on the caps 10a and 10b to heat them. The heat concentrated on the caps 10a and 10b is conducted from supporters 11a and 11b to a metallic casing 1, and then is radiated from the outer surface of the casing 1 to outside air. A heat radiating operation is preferable because the outer surface of the casing 1 is large. Therefore, temperature rising-up at the lamp 5 and inside the casing 1 can be restrained. Furthermore, heating ratio of a luminous diffuse transmitting plate 12 disposed at a front face can be reduced, and particularly, when a liquid crystal panel is disposed at the front face, heat deterioration thereof can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a lighting device that uses a low-pressure discharge lamp as a light source and is suitable as a backlight for a liquid crystal television or a liquid crystal meter.

(Conventional technology) LCD televisions, LCD meters, etc. display light on the LCD screen by shining light from the back of the LCD panel. Such backlights illuminate the entire LCD screen with a predetermined spread. Therefore, a lighting device that can emit light with uniform brightness is required.

This type of backlight has traditionally housed a hot cathode or cold cathode fluorescent lamp in a casing with a quadratic curved bottom and a reflective surface on its inner surface, and the light from this lamp is reflected by the reflective surface. A lighting device is used in which the light is emitted to the outside through a light diffusing and transmitting plate installed in the opening of the casing.

When a hot cathode or cold cathode fluorescent lamp is used as a light source, compared to an incandescent lamp, such a lamp has superior luminous efficiency, generates less heat, has a long life, and has a long discharge path, so the light emitting area is small. It has the advantage that the light distribution is large and the light distribution can be easily made uniform.

In particular, in the case of fluorescent lamps, it is easy to configure the discharge path into a bent shape, such as a U-shape or a W-shape, and such bent fluorescent lamps have a flat light-emitting surface that is wider, so that a predetermined spread can be achieved. This has the advantage of making it easier to illuminate the display surface with uniform brightness.

By the way, when attaching a fluorescent lamp like the one mentioned above to a casing, conventionally a structure was adopted in which caps made of silicone rubber were attached to both ends of the fluorescent lamp, and these silicone rubber caps were fixed to the side walls of the casing. was.

Such a fixed structure has the advantage that the silicone rubber cap absorbs shock and vibration, thereby preventing damage to the lamp, and also has excellent electrical insulation properties.

In particular, when applied to a vehicle meter, etc., it is advantageous in terms of shock resistance and vibration resistance.

(Problems to be Solved by the Invention) However, with the lamp support structure as described above, there is a problem in that the temperature at the end of the lamp and inside the casing increases due to the heat released from the electrodes.

That is, in hot cathode fluorescent lamps as well as cold cathode fluorescent lamps, the electrodes generate heat during lighting, which heats the bulb and is emitted into the casing through the bulb wall. As a result, the lamp temperature and the temperature inside the casing rise, heating the light diffusing and transmitting plate on the front surface. In particular, there is a concern that it will have a major negative effect on the liquid crystal panel on the front side.

The present invention aims to provide a lighting device that smoothly releases heat from an electrode portion to the outside and prevents temperature rise inside the lamp and casing.

[Structure of the invention]

(Means for Solving the Problems) The present invention comprises a casing made of metal, surrounds the outer periphery of the bulb facing the electrode portion of the discharge lamp with a thermally conductive member, and connects the thermally conductive member to the casing. It is characterized by being thermally conductively connected to.

(Function) According to the present invention, the heat released from the electrode part of the discharge lamp is
The heat is transmitted from the heat conductive member provided around the outside of the bulb to the metal casing, and is released to the outside air from the wide outer surface of the casing, thereby preventing a rise in temperature inside the lamp and the casing.

(Example) The present invention will be described below based on an example shown in FIGS. 1 to 3.

In the figure, 1 is a casing, which is made of metal such as iron, stainless steel, or aluminum, and has a hammer-shaped cross section with a quadratic curve. A partition protrusion 2 is attached or integrally formed along the longitudinal direction at the center of the bottom surface of the casing 1. As shown in FIG. 2, this protrusion 2 has a substantially triangular upper cross section. The entire bottom surface and protrusion 2 of the casing 1 are made into a reflective surface 3.

A pair of gutter-shaped support portions 11a are provided on one side wall 4 of the casing 1.
, flb are integrally molded.

A bent fluorescent lamp 5 is accommodated in such a casing l.

In this embodiment, a U-shaped fluorescent lamp 5 is used. That is, 6 is a valve bent into a U-shape, and this valve 6 has straight parts 8a and 8b that are substantially parallel to each other at both ends of a U-shaped bent part 7, and these straight parts 8a
, 8b are sealed with cold cathode type electrodes 9a, 9b.

Further, a phosphor coating (not shown) is formed on the inner surface of the bulb 6, and a predetermined amount of mercury and a starting rare gas such as argon or xenon are sealed inside the bulb G.

The linear portion 8a in such a fluorescent lamp 5,
A metal cylindrical cap 10a is attached to the end of the bulb 6 so as to cover the electrodes 9a and 9b on the outside of the bulb 6.
, lOb, and these metal caps lOb.
oa and lOb are closely fixed to the outer surface of the bulb 6 by means of an adhesive having excellent thermal conductivity, caulking, or the like.

The fluorescent lamp 5 is housed in the casing 1 so that its straight portions 8a and 8b are substantially parallel to the bottom surface of the casing 1. In this case, the protrusion 2 is interposed between the substantially parallel straight parts 8a and gb of the U-shaped valve 6, that is, the protrusion 2 separates the adjacent double-sided line parts 8a and 8b. It is installed.

Note that the protrusion 2 is cut out at a portion facing the bent portion 7 of the U-shaped bulb 6, and the U-shaped bent portion 7 of the lamp 5 is disposed in this cut portion.

In the fluorescent lamp 5, the caps 10a and 10b, which are attached to both ends, are fitted into the gutter-like support portions 11a and llb formed on the side wall 4 of the casing l, and these caps loa and lOb are gutter-shaped. Support part 11
a, It is tightly fixed to llb by caulking. Note that the caps 10a and 10b are provided with a gutter-like support portion 11.
a.

Instead of caulking, an adhesive such as silicone, which has excellent thermal conductivity and electrical insulation properties, may be used to fix the flb.

Further, the U-shaped bent portion 7 of the lamp 5 is supported by an elastic pad 15 such as silicone rubber, which is located at the cutout portion of the protrusion 2 and is attached to the casing 1.

A light diffusing and transmitting plate 12 is attached to the upper opening of the casing l. This light diffusing and transmitting plate 12 is made of acrylic resin or the like and has a milky white color and has a light diffusing effect. A portion 13 is formed.

The thickness of this thick portion 13 gradually becomes thinner as it moves away from the valve 6.

The operation of the embodiment with such a configuration will be explained.

When the fluorescent lamp 5 is energized and turned on, it emits light along the shape of the U-shaped bulb 8.

A part of the light emitted from the bulb 6 is reflected by the reflective surface 3 on the bottom of the casing 1 and directed toward the light diffusing/transmitting plate 12 at the upper end, and the remaining light is directed directly toward the light diffusing/transmitting plate 12. Therefore, almost all of the light emitted from the lamp 5 is irradiated to the outside through the light diffusing and transmitting plate 12.

In this case, the substantially parallel straight portion 8a of the U-shaped valve 6,
Since the protrusion 2 is interposed between 8b, this protrusion 2
reflect the light emitted from the linear portions 8a and 8b upward, respectively, and increase the brightness of the surface of the light diffusing and transmitting plate 12 facing between the linear portions 8a and 8b.

Further, since the thick part 13 is formed on the inner surface of the light diffusing and transmitting plate 12, the thick part 13 faces directly above the bulb 6, so that the amount of light transmitted through the thick part is reduced. As the wall thickness decreases as the distance from the portion 13 increases, the amount of light transmitted increases. Therefore, uneven brightness of the light diffusing and transmitting plate 12 is eliminated.

For this reason, it is possible to provide uniform brightness over the entire surface of the light diffusing and transmitting plate 12.

During lighting of such a lamp, the electrode 9a.

9b generates heat and heats the bulb wall around electrodes 9a and 9b.

In this embodiment, metal cylindrical caps 10a and 10b with excellent thermal conductivity are placed on the outside of the bulb 6 to cover the electrodes 9a and 9b.
The heat released from the cylindrical caps 10 a and 9b
a, is collected in a fob and heated. The heat of these caps loa and lob is transferred to the trough-like support part 1
The heat is conducted to the metal casing l through 1a and llb, and is discharged to the outside air through the outer surface of this casing l. At this time, since the outer surface of the casing l is wide, a good heat dissipation effect is achieved.

Therefore, the rise in the temperature of the lamp 5 and the temperature inside the casing l is suppressed, and the rate of heating the light diffusing and transmitting plate 12 on the front side is reduced, and in particular, the liquid crystal panel (not shown) installed on the front side is thermally degraded. There will be no more letting go.

Note that the present invention is not limited to the above embodiments.

That is, the metal cap 10a and the job are the fourth
As shown in the figure as a second embodiment, an uneven surface 1 is provided on the outer surface.
0aa may be formed.

Further, these metal caps LOa and LOb may also be used as bases by connecting lead wires connected to the electrodes 9a and 9b to these metal caps LOa and LOb.

Further, in the above embodiment, a U-shaped bent lamp was used as the fluorescent lamp 5, but the present invention is not limited to this.
It may be W-shaped or the like. Furthermore, as shown in FIG. 5 as a third embodiment, a straight tube fluorescent lamp 20.20 may be used. Note that in FIG. 5, members having the same functions as those in the first embodiment are designated by the same numbers, and explanations thereof will be omitted.

Furthermore, the present invention is also applicable to cases such as the fourth embodiment shown in FIGS. 6 to 9.

That is, this type of lighting device is sometimes used in a low-temperature atmosphere, and in this case, if the lamp temperature is low, starting performance is not good and the light output during stable lighting is reduced. In order to improve this problem, a method is adopted in which the lamp is heated by an electric heater.

When heating a lamp with a heater, it is desirable to heat the entire lamp evenly, for example, uniformly.

This can be achieved by placing a heater over the entire length of the lamp, but if this is done, the heater will block the light emitted from the lamp when the lamp reaches stable lighting, making it impossible to utilize the light output effectively. There is a problem.

Therefore, in this embodiment, a shape memory spring is used to extend the heater to warm the entire lamp when starting the lamp at low temperatures, and to contract the heater when the lamp reaches stable lighting. It is now moved away from the effective light emitting surface.

The details will be explained below.

In the figure, reference numeral 30 denotes a straight tube type fluorescent lamp, and cold cathode type electrodes 9a and 9b are sealed at both ends of the bulb 31.
A metal cylindrical cap 10a having the same purpose as the first embodiment and covering the periphery of portions a and 9b.

10b is covered.

A coil body 32 is spirally wound around the outside of the valve 31.

As shown in cross section in FIG. 9, the coil body 32 includes a coil wire 34 made of a martensitic transformed shape memory metal made of titanium or nickel alloy, and also serves as a heater, in a focusing tube 33 made of a heat shrink tube or the like. The return coil wire 35 is inserted therethrough. In other words,
A coil wire 34 made of shape-memory metal and a return coil wire 35 that also serves as a heater are bundled with a focusing tube 33 made of a heat-shrinkable tube, and this is formed into a spiral shape to form a valve 3.
It is wrapped around the outside of 1. Note that the return coil wire 35, which also serves as a heater, is covered with an insulating coating 36 for electrical insulation.

One end of this coil body 32 is fixed to the outer surface of one end of the valve 3I by a stopper tube (band) 37 made of, for example, a heat-shrinkable tube shown in FIGS. 6 and 7, and the other end is fixed in the axial direction. It is possible to move freely.

Therefore, when the temperature of such a coil body 32 is below a predetermined temperature, the coil shape or the valve 31 is changed as shown in FIG.
extends in the axial direction of the valve 31 to cover almost the entire length of the valve 31 in a spiral shape, and when the temperature exceeds a predetermined temperature, the coil shape changes as shown in FIG. It contracts in the axial direction of the valve 31 and gathers at one end of the valve 31.

Note that the return coil wire 35 includes a power supply connection lead wire 38.
The power supply connection lead wire 38 is guided through support rings 39 provided at various places on the coil body 32 to prevent it from getting tangled when it is shrunk.

In such a configuration, when the ambient temperature is below a predetermined temperature, the coil shape of the coil body 32 extends in the axial direction of the bulb 31 to cover almost the entire length of the bulb 31 in a spiral shape, as shown in FIG. Therefore, when current is passed through the heater/return coil wire 35 through the power supply connection lead wire 38, the heater/return coil wire 35 generates heat and heats the wall surface of the valve 31. This promotes evaporation of mercury, improves startability, and increases light output.

On the other hand, when the ambient temperature reaches a predetermined temperature or higher, the coil body 32 is caused to
As shown in FIG. 7, the coil shape contracts in the axial direction of the bulb 31 and comes to be gathered at one end of the bulb 31. Therefore, the coil body 32 does not cover the main light emitting surface of the bulb 31, and the proportion of light emitted from the lamp 30 blocked by the coil body 32 is reduced.

Note that when the state shown in Fig. 7 is reached, the power supply connection lead wire 38
The current passing through the heater/return coil wire 35 is stopped.

Such control of energization is possible by measuring the valve temperature with a temperature sensor (not shown).

In addition, in the case of the fourth embodiment, the shape memory spring is
Although a martensitic transformed shape memory metal made of titanium and nickel alloy was used, for example, a trans-in-prene shape memory resin may also be used.

Further, reverse martensitic transformation, which is the opposite of martensitic transformation, may be used.

Furthermore, in the case of the fourth embodiment, since the single wire 35 serves as both the heater and the return coil, there is an advantage that the number of wires used is reduced. The heater wire 4.degree. and the return coil 41 may be separated from each other so that the heater wire 4.degree. and the return coil 41 can be separated from each other, and in this case, the resistance characteristics of the heater and the spring characteristics of the coil can be independently selected.

Furthermore, the present invention is not limited to cold cathode type electrodes;
It may be of a hot cathode type, or it may be a rare gas discharge lamp in which only rare gas is sealed without mercury in the bulb.

〔Effect of the invention〕

As explained above, according to the present invention, the heat emitted from the electrode part of the discharge lamp is transmitted from the thermally conductive member provided around the outside of the bulb to the metal casing, and the outside air is passed through the wide outer surface of the casing. This prevents temperature rise inside the lamp and casing, extending the life of the entire device.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is an exploded perspective view of the entire lighting device, FIG. 2 is a sectional view, and FIG. 3 is a 4 is a perspective view of a metal cap showing a second embodiment of the present invention, and FIG. 5 is an exploded perspective view of the entire lighting device showing a third embodiment of the present invention. 6 to 9 show a fourth embodiment of the present invention, FIGS. 6 and 7 are side views of the lamp showing different operating states of the coil body, and FIG. 8 is a side view of the lamp shown in FIG.
9 is an enlarged cross-sectional view of the coil body shown in the section (■) in FIG. 8, and FIG. 10 is a cross-sectional view of the coil body showing a fifth embodiment of the present invention. ■... Casing, 3... Reflective surface, 5... Fluorescent lamp, 6... Bulb, 9a, 9b... Electrode, 1
0a, 1Ob--cap, lla, llb
-...Gutter-like support part, 12...Light diffusion transmitting plate, 32...Coil body, 34...Shape memory metal coil wire, 35...Heater return coil wire. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 7/'' ■ 2nd VJ Figure 3

Claims (1)

[Claims] A tube-shaped discharge lamp is housed in a casing that is open on one side,
In a lighting device that transmits light emitted from the discharge lamp through a light diffusion and transmission plate provided in the opening and irradiates the front surface of the light diffusion and transmission plate, the casing is made of metal, and the discharge lamp is A lighting device characterized in that an electrode is surrounded by a thermally conductive member, and the thermally conductive member is thermally conductively connected to the casing.