JPH03210752A - Flat fluorescent lamp - Google Patents

Abstract

PURPOSE:To improve facility at the time of inserting a glass bulb, and to improve the cooling effect of a pair of sealing members by protruding outward flanges on the opening ends of the sealing members of flat fluorescent lamp. CONSTITUTION:A pair of metal caps 23a, 23b are formed into bottomed long cylinders by the drawing of a conductive metal plate and so on, and outward flanges 25a, 25b are protruded on the opening ends thereof, in an integrated manner. When the opening ends along the axis of a glass bulb 22 are fitted to the caps 23a, 23b, even through the alignment is slightly shifted, the opening ends of the bulb 22 are put on the flanges 25a, 25b, and are guided to the opening ends thereof, whereby facility of the insertion can be improved. Since the caps 23a, 23b are connected to a lighting circuit 26, and thereby work as electrodes, the temperature of a flat fluorescent lamp 21 can be reduced by approximately 20 deg.C due to the existence of the pair of flanges 25a, 25b.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a flat fluorescent lamp suitable for a small backlight etc. that illuminates a small liquid crystal display panel from the back side. This invention relates to a flat fluorescent lamp that is further improved in size and thickness.

(Prior Art) Conventionally, as a backlight for illuminating a liquid crystal display panel such as a liquid crystal television from the back, there is a lighting device 1 shown in FIG. 9, for example.

This illumination device 1 has a reflective film 2a coated on the inner circumferential surface of a reflector 2 having a substantially semicircular longitudinal section. The open end of the container 2 is closed by stacking first and second diffusion plates 4.5 on top of each other, and a liquid crystal display panel 6, for example, is stacked in close contact with the upper surface of these diffusion plates 4.5.

In other words, the direct light from the fluorescent lamp 3 and the reflective film 2 of the reflector 2
By diffusing the light reflected by a in a plane by the first and second diffusion plates 4 and 5 and equalizing the brightness on the upper surface of the second diffusion plate 5 in a plane, a surface light source is created. , so that almost the entire rear surface of the liquid crystal display panel 6 is illuminated almost uniformly.

However, in such a conventional lighting device 1, in order to convert the straight circular tube fluorescent lamp 3, which is a linear light source, into a surface light source, the reflector 2 and the first and second diffuser plates 4.5 are used, respectively. The number of parts is increasing.

For this reason, the conventional lighting device 1 does not necessarily have high luminance efficiency, which hinders the reduction in size, weight, and thickness.
There is a problem in that it increases manufacturing costs.

Therefore, a flat fluorescent lamp 1 shown in FIGS. 10 and 11 is considered. This flat fluorescent lamp 11 is not conventionally known, and has a pair of left and right metal caps 13a, 1 on the outer periphery of both ends of the axial opening of a flat cylindrical glass bulb 12.
The open end portions of the glass bulbs 3b are fitted onto the outside and fixed airtightly, and an appropriate amount of mercury and rare gas are sealed inside, and a fluorescent film 14 is coated on almost the entire inner peripheral surface of the glass bulb 12. , the upper surface in the figure is formed as a light emitting surface 15, which illuminates a liquid crystal display panel (hereinafter referred to as an LCD panel) or the like.

On the other hand, the pair of metal caps 13a and 13b are each formed into an elongated cylindrical shape with a bottom by drawing a conductive metal plate, and as shown in FIG. 11, are electrically connected to the lighting circuit 16 and cooled. It is also configured as an electrode such as a cathode.

Therefore, by applying a required voltage between these metal caps 13a and 13b, both 13a and 13b can be
A planar discharge can be caused within the glass bulb 12 between the inner surfaces of the glass bulbs.

Since the flat fluorescent lamp 11 configured in this manner is a chipless type that does not include an exhaust pipe, when filling rare gas such as argon gas into the flat fluorescent lamp 11, it is done by so-called vacuum sealing. .

That is, on the outer periphery of one opening end in the axial direction of the glass bulb 12, a required one of the pair of metal caps 13a, 13b,
For example, after the open end of 13a is airtightly fitted and fixed, the first
As shown in Figure 2, the other metal cap 13b is placed in the fixing recess 18a of the heating carbon stand 18 built in the chamber 17, which is a closed container that can be freely supplied and exhausted. Insert it.

Next, the other open end of the glass bulb 12 is simply inserted into the open end of the metal cap 13b to stand up.

Therefore, a slight gap is formed between the inner circumferential surface of the lower metal cap 13b and the lower end of the middle opening of the glass bulb 120.

Therefore, when the on-off valve 17a of the chamber 17 is opened and the inside of the chamber 17 is evacuated, the inside of the glass bulb 12 is almost simultaneously evacuated through the gap between the metal cap 13b at the bottom in the figure and the lower end of the opening in the figure of the glass bulb 12. Exhausted.

Next, when a rare gas such as argon gas is pumped into the chamber 17, this rare gas passes through the gap between the metal cap 13b and the lower end of the opening of the glass bulb 12, and enters the glass bulb 12 at a rate of, for example, 1°Q Iotr. Noble gas is injected under pressure.

After that, the heating carbon table 6 is heated in this rare gas atmosphere.
For example, a required voltage is applied for a required period of time through a pair of conductors 19a and 19b to heat the substrate.

As a result, the lower metal cap 13b in the figure, which is tightly fitted into the fixing recess 18a of the heating carbon stand 18 that is being heated, is heated, and furthermore, the metal cap 13b that is being fitted into the metal cap 13b that is being heated is heated. The lower end of the opening of the glass bulb 12 is heated and melted in a rare gas atmosphere, and the glass bulb 12 is then cooled to form the metal cap 13.
b hermetically sealed inside.

Note that heat welding between the opening ends of the glass bulb 12 and the pair of metal caps 13a, 13b may be performed by high-frequency induction heating of the pair of metal caps 13a, 132b.

(Problem to be Solved by the Invention) However, in such a flat fluorescent lamp 11, the bodies of the pair of metal caps 13a and 13b are almost straight bodies, and each opening end is connected to both opening ends of the glass bulb 12 into which it is fitted. It is simply an opening to allow it to fit in.
A pair of metal caps 1 are attached to the open end of the glass bulb 12.
There is a problem in that it is not necessarily easy to fit the open ends of 3a and 13b inside, and the workability is low.

In addition, as shown in FIGS. 13(A) and 13(B), when the LCD panel 6 is mounted on the light emitting surface 15 of the flat fluorescent lamp 11 with its lower surface in close contact with the flat fluorescent lamp 11, when the flat fluorescent lamp 11 is turned on, , both the glass bulb 12 and the pair of metal caps 13a, 13b rise in temperature, and the temperature of the pair of metal caps 13a, 13b is higher than that of the glass shown by the curve 8 in the figure, as shown in the curve in FIG. Valve 12
temperature is higher than that of

In FIG. 14, the temperature of the flat fluorescent lamp 11 is plotted on the vertical axis, and the lamp power supplied to the pair of metal caps 13a, 13b is plotted on the horizontal axis. The short axis is 8+nm, the argon gas filling pressure is 3Q jor+, and the pair of metal caps 13a and 13b are made of 426 alloy (52% Fe, 42% Ni).
, a 6% Cr alloy), the temperature of the flat fluorescent lamp 11 is shown when the flat fluorescent lamp 11 is lit at a high frequency of 40 KHz.

By the way, the upper limit temperature for liquid crystal panels is generally about 65 degrees Celsius.
The LCD panel 6 is replaced with a flat fluorescent lamp 11.
When used in direct contact with the LCD panel 6
There is a risk that the temperature will rise above its upper limit temperature, causing deterioration or destruction.

Therefore, the present invention has been made in consideration of the above circumstances, and its purpose is to improve the ease of inserting both axial ends of a glass bulb into the open ends of a pair of sealing members, and to prevent overheating of the LCD panel. The object of the present invention is to provide a flat fluorescent lamp which can be prevented from being destroyed.

[Structure of the invention]

(Means for Solving the Problems) The first invention of the present application provides an axial direction of the glass bulb to the open ends of the pair of sealing members by protruding outward flanges at the open ends of the pair of sealing members. It is designed to improve the ease of insertion of the open end, and is constructed as follows.

In other words, the first invention of the present application is to coat the inner surface of a flat cylindrical glass bulb with a phosphor, and to cover both ends of the axial opening of the bulb with a pair of sealing members made of a conductive material and used for common electrodes. The bulb is airtightly fitted and sealed into the open end, mercury and rare gas are sealed in the bulb, and outward flanges are respectively provided protruding from the open ends of the pair of sealing members.

Further, a second invention of the present application is characterized in that a liquid crystal display panel is installed on the pair of outward flanges.

(Function) <First invention> When the axial opening end of the glass bulb is inserted into the opening end of the sealing member, even if the alignment is slightly shifted, the opening end of the glass bulb will not fit into the opening end of the sealing member. It abuts an outward facing flange on the open end and is guided into the open end.

Therefore, the ease with which the open end of the glass bulb can be inserted into the sealing member can be improved, and the workability thereof can be improved.

In addition, the temperature of the pair of sealing members rises to a relatively high temperature when the flat fluorescent lamp is turned on, but since the outer surface of the sealing members is expanded by the outward flange, the cooling effect can be increased accordingly. can.

<Second Invention> Since the LCD panel is mounted on the pair of flanges of the flat fluorescent lamp 11, an air layer is formed in the space between the flat fluorescent lamp and the LCD panel.

The air layer in this space has a heat shielding effect that prevents the heat generated when the flat fluorescent lamp is turned on from being directly transferred to the LCD panel and causing it to overheat.It also protects the LCD panel, which is sensitive to heat, from overheating and causing its deterioration. or destruction can be prevented.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 8.

FIG. 1 is a perspective view of an embodiment of the present invention, and in the figure, a flat fluorescent lamp 21 has an axial length of about 21 mm, for example.
The glass bulb 22 is formed in a small size with a length in the width (major axis) direction of about 18 mm, and the glass bulb 22 is formed into a flat shape with an oval vertical cross section.

The flat fluorescent lamp 21 is made of this flat cylindrical glass bulb 2.
A pair of left and right metal caps 23a and 23b are fitted and fixed to the outer periphery of both ends of the axial opening of the metal cap 2, respectively, and an appropriate amount of mercury and rare gas are sealed inside.

As shown in FIG. 2, the glass bulb 22 is formed into a flat, elongated cylindrical shape with an elliptical longitudinal section, and the upper and lower surfaces 22a and 22b in the figure are substantially flat.

Further, the glass bulb 22 has a pair of front and rear surfaces 22c and 22d, which face each other in the longitudinal direction, and are formed into outwardly convex curved surfaces.

A fluorescent film 24 is coated on the entire inner circumferential surface of the glass bulb 22.
The lower surface 22b is made thinner than the inner surface film thickness 24b,
By increasing the amount of light that passes through the fluorescent film 24a on the upper surface 22a side, the upper surface 22a becomes a light emitting surface that increases the amount of light output from the upper surface 22a of the glass bulb 22 to the outside.
is formed.

Since this light-emitting surface 22a is formed as a flat surface, surface light is emitted with the same brightness over the entire surface, and therefore, this light-emitting surface 22a
By arranging a liquid crystal display panel (not shown) in parallel on the outer surface of 2a, the back surface of the liquid crystal display panel can be illuminated over the entire surface with substantially equal brightness.

On the other hand, the pair of metal caps 23a and 23b are each formed into an elongated cylindrical shape with a bottom by drawing a conductive metal plate, and outward flanges 25a and 25 are provided at both open ends of the metal caps 23a and 23b.
b is integrally provided.

As shown in FIG. 1, these metal caps 23a and 23b are each electrically connected to a lighting circuit 26, and are also configured as electrodes such as a cold cathode.

Therefore, by applying a required voltage between these metal caps 23a and 23b, both 23a and 23b can be
A planar discharge can be caused within the glass bulb 22 between the electrode surfaces on the inner surface of the glass bulb 22.

Note that the entire outer peripheral surfaces of the pair of metal caps 23a and 23b may be coated with an insulating film such as a glass film to improve electrical insulation.

As shown in FIG. 3, the flat fluorescent lamp 21 configured in this way has a pair of outward flanges 25a,
The mounting position is determined by placing the LCD panel 27 on the frame 25b in a substantially parallel manner, so that the back surface of the LCD panel 27 faces the light emitting surface 22a of the flat fluorescent lamp 21.

For this purpose, as shown in FIGS. 3 and 4FgJ,
From the back of the CD panel 27, the light emitting surface 22a of the flat fluorescent lamp 21 is connected to a pair of outward flanges 25a.

They are spaced apart by an amount corresponding to the protrusion height of 25b, so that an air layer 28 can be formed between them.

Since this air layer 28 has a heat shielding or cooling effect, the heat generated when the flat fluorescent lamp 21 is lit is shielded or cooled by the air layer 28, and the heat generated by the flat fluorescent lamp 21 is directly transferred to the LC.
It is possible to prevent heat from being transferred to the D panel 27, and
Heating of the CD panel 27 can be prevented.

FIG. 5 shows the heat shielding effect of this air layer 28, and the curve C in the figure shows the L
The curved line in the figure shows the temperature change of the LCD panel 27 assembled to the flat fluorescent lamp 11 that is not equipped with the pair of outward facing 7-lunges 25a and 25b, and the former C is more sensitive to the temperature change of the CD panel 27. This shows that the temperature is about 20°C lower than the latter.

That is, according to this embodiment, the pair of outward flanges 25
The temperature of the flat fluorescent lamp 21 is set to about 20°C by a and 25b.
This shows that it is possible to reduce the level of

Therefore, the upper limit temperature for use is approximately 65°C, and LC is susceptible to overheating.
It is possible to prevent overheating of the D panel and prevent its destruction or deterioration.

FIG. 6 is a perspective view of the main parts when the flat fluorescent lamp 21 configured as described above is incorporated into a color electronic vinyl binder for a camera-integrated video camera, etc. In the figure, the mounting part 29 of the color electronic viewfinder is As shown in FIGS. 7 and 8, a pair of caps 30a and 30b are held between the flat fluorescent lamps 21 in the axial direction while the flat fluorescent lamp 21 is erected with its major axis aligned with the vertical direction.
has been established.

These caps 30a and 30b are made of conductive and combustible metal plates or the like, and are electrically connected to a lighting circuit (not shown).

Further, an LCD panel 27 is fixed upright on the mounting portion 29 on the sides of the pair of bases 30a and 30b.
As shown in FIGS. 7 and 8, the back surface of the LCD panel 27 is connected to a pair of outward flanges 25a of the flat fluorescent lamp 21.
, 25b.

Therefore, as described above, the pair of outward flanges 25
a and 25b prevent the back surface of the LCD panel 27 from coming into close contact with the light emitting surface 22a of the flat fluorescent lamp 21,
The two are separated, and an air layer 28. is formed.

Therefore, in this embodiment as well, the heat shielding effect of the air layer 28 can prevent overheating of the LCD panel 27 and prevent its destruction.

In addition, the flat fluorescent lamp 21 is connected to a pair of bases 308° 30b.
By holding it in the axial direction, it is assembled integrally with the color electronic viewfinder, and at the same time, it is electrically connected to a lighting circuit (not shown).

〔Effect of the invention〕

As explained above, in the present invention, the outward flanges are protruded from the open ends of the pair of sealing members of the flat fluorescent lamp, so that it is easy to insert the open end of the glass bulb into the opening of the sealing members. In addition, since the outer surface of the sealing member can be enlarged by the outward flange, the cooling effect of the sealing member can be enhanced.

In addition, since the liquid crystal display panel is installed on a pair of flanges, the second invention prevents the LCD panel and the flat fluorescent lamp from coming into close contact with each other, separates them, and forms an air layer between them. The heat shielding effect of the air layer can prevent the heat generated when the flat fluorescent lamp is turned on from being directly transferred to the liquid crystal display panel.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an embodiment of the first invention of the present application, Fig. 2 is an exploded perspective view of main parts of the embodiment shown in Fig. 1, and Fig. 3 is an embodiment of the second invention of the present application. The front view of the example, Figure 4 is an enlarged view of the ■ section in Figure 3, Figure 5 is a graph showing temperature changes, etc. of the LCD panel shown in Figure 3, and Figure 6 is from the flat fluorescent lamp shown in Figure 1. FIG. 7 is a front view of the color electronic viewfinder, FIG. 8 is a plan view of FIG. 7, and FIG. 9 is a diagram of the conventional illumination device. FIG. 10 is an exploded perspective view of another flat fluorescent lamp, FIG. 11 is an exploded perspective view of the flat fluorescent lamp shown in FIG. 10, FIG. 12 is a front view of a chamber for vacuum sealing, and FIG. 13 (A) is a front view showing the flat fluorescent lamp shown in Fig. 10 attached with the back of the LCD panel in close contact, and Fig. 13 (B) is the same view (A).
14 is a graph showing temperature changes of the glass bulb and the pair of metal caps of the flat fluorescent lamp shown in FIG. 10. 21... flat fluorescent lamp, 22... glass bulb,
23a, 23b...a pair of metal caps, 24...
- Fluorescent film, 25a, 25b... outward flange, 27
...LCD panel, 28...air layer.

Claims (1)

[Claims] 1. A phosphor is coated on the inner surface of a flat cylindrical glass bulb, and both axial opening ends of the bulb are connected to openings in a pair of sealing members made of a conductive material that share electrodes. A flat fluorescent lamp, characterized in that the end portions are hermetically fitted and sealed, mercury and a rare gas are sealed in the bulb, and outward flanges are respectively protruded from the open ends of the pair of sealing members. lamp. 2. The flat fluorescent lamp according to claim 1, further comprising a liquid crystal display panel mounted on the pair of outward flanges.