JPH03210751A - Flat fluorescent lamp - Google Patents

Abstract

PURPOSE:To prevent the deformation of an exposed surface by fitting both ends of a glass bulb along the axis, in a sealing member that seals both ends of the opening along the axis of the glass bulb, and by providing recessed parts for fitting that surrounds both the inner and outer circumferential surfaces thereof. CONSTITUTION:Both ends of the opening of a glass bulb 22 are fitted into recessed parts 27a, 27b for fitting of a pair of metal caps 23a, 23b. When the caps 23a, 23b are heated by high frequency induction heating and so on, the both ends of the opening of the bulb 22 that are in contact with the inner surface thereof are melted by the pair of recessed parts 27a, 27b heated at a high temperature. Since the melted glass is regulated by the inner and outer circumferential walls of the recessed parts 27a, 27b the covering of a part of electrode surfaces 29a, 29b by the molten glass that intrudes therein, is prevented. The shrinking of the electrode effective areas of the electrode surfaces 29a, 29b of the caps 23a, 23b, can thus be prevented, as well as the deformation thereof.

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 lighter and thinner.

(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. 13, 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
The reflected light reflected by a is diffused in a plane by the first and second diffusion plates 4.5, and the brightness on the upper surface of the second diffusion plate 5 is equalized in a plane, thereby creating a surface light source. , so that almost the entire rear surface of the liquid crystal display panel 6 is illuminated almost uniformly.

However, in such a conventional lighting bag rI11,
In order to convert the straight circular tube fluorescent lamp 3, which is a linear light source, into a surface light source, a reflector 2 and first and second diffusion plates 4.5 are required, resulting in a large number of parts.

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. 14 and 15 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.
3b are externally fitted and fixed, and an appropriate amount of mercury and rare gas are sealed inside, and a fluorescent film 14 is coated on the entire inner peripheral surface of the glass bulb 12.

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 have outward flanges 15a and 15 at both open ends.
b is integrally provided.

As shown in FIG. 1, these metal caps 13a and 13b are electrically connected to the lighting circuit 16, and are also configured as electrodes such as cold cathodes.

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, i3b,
For example, after the 13a is airtightly fitted and fixed to the outside, as shown in FIG.
Insert the other metal cap 13b into the cap with its bottom facing downward in the figure.

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 peripheral surface of the lower metal cap 13b and the lower end of the opening of the glass bulb 12 in the drawing.

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 pressure of, for example, 1091 ort. is press-fitted.

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.

(Problems to be Solved by the Invention) However, in such a flat fluorescent lamp 11, the sealing strength between the glass bulb 12 and the pair of metal caps 13a and 13b cannot necessarily be increased, and electrical properties such as discharge stability There is a possibility that the stability cannot necessarily be improved.

That is, as shown in FIG. 17, a pair of metal caps 13a,
Since the open end of the glass bulb 13b is fitted over the outside and heat fused, the outer peripheral surface of the open end of the glass bulb 12 and the pair of metal caps 13
The inner circumferential surfaces of a and 13b are simply joined, and this joint area is not necessarily large.

Furthermore, since the inner circumferential surface of the open end of the glass bulb 12 is free, there is a possibility that the sealing strength between the two cannot necessarily be increased.

Further, as shown in FIG. 18(A), the glass bulb 12
When the glass bulb 12 is heated and melted, the upper and lower surfaces 12a and 12b in the figure, which face each other in the direction of the short axis a in the longitudinal section of the glass bulb 12, may sag inward and deform into a so-called gourd shape.

For this reason, the inner surfaces forming the electrode surfaces of the pair of metal caps 13a and 13b are covered with molten glass in a gourd shape, and the surface area is reduced, which may adversely affect electrical characteristics such as adversely affecting the stability of discharge. There is.

Furthermore, as shown in FIG. 18(B), if the jig holding the pair of metal caps 13a, 13b and its heating temperature are uneven, there is a probability that the melting state of the glass bulb 12 will be uneven. In this case, in addition to the above-mentioned problem, the following problem arises.

In other words, since the pair of metal caps 13a and 13b are also used as electrodes, these metal caps 13a and 13b are also used as electrodes.
, 13b, the glass bulb 12
The area where is not melted and adhered becomes an effective area as an electrode.

In addition, when the cold cathode and the distance between the electrodes are relatively short, that is, when the flat fluorescent lamp 11 is small, the lamp voltage is almost determined by the cathode drop voltage, and the cathode drop voltage is determined by the shape and material of the electrodes. , lamp current, and filled gas pressure are determined by the surface area of the electrode.

Therefore, as shown in FIG. 18(B), if the effective surface area of the pair of metal caps 13a and 13b as electrodes is reduced or the exposed surface shape of the electrode surface is deformed, the desired electrical characteristics cannot be obtained. There is a risk.

The present invention has been made in consideration of the above circumstances, and its purpose is to improve the sealing strength between the glass bulb and a pair of sealing members that also serve as electrodes, and to improve the stability of electrical characteristics. Our objective is to provide a flat fluorescent lamp that can.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a pair of metal caps 13a and 1 which also serve as electrodes.
A recessed portion is formed on the inner surface of the glass bulb into which both ends of the axial opening of the glass bulb are fitted, and is constructed as follows.

That is, in the present invention, a phosphor is coated on the inner surface of a flat cylindrical glass bulb, and both axial opening ends of the bulb are fitted into fitting recesses of a pair of sealing members made of a conductive material. Both the inner and outer circumferential surfaces of both open ends are surrounded and heat fused to airtightly seal these open ends, mercury and rare gas are sealed in this bulb, and the pair of sealing members are connected to electrodes. It is characterized by being shared by each.

(Function) When sealing a pair of sealing members to the axially open ends of a glass bulb, first, both axially open ends of the glass bulb are fitted into the fitting recesses of the pair of sealing members.

Next, this pair of sealing members is heated using, for example, a carbon heater or high frequency induction heating.

Then, the fitting end of the glass bulb fitted into this fitting recess is heated and melted, but both its inner and outer circumferential surfaces are restricted by the inner and outer peripheral walls of the fitting recess, so that the radially inner electrode surface of the glass bulb is heated and melted. This prevents the sealing member from sagging, thereby increasing the stability of the electrical characteristics of the sealing member as an electrode due to the sag.

Furthermore, since both ends of the axial opening of the glass bulb are fitted into the fitting recess of the sealing member, both the inner and outer surfaces of the fitting end are joined to the annular inner and outer circumferential walls of the fitting recess, increasing the joint area. Therefore, it is possible to improve the sealing strength of both of them.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 12.

FIG. 1 is a perspective view of an embodiment of the present invention, and in the figure, a flat fluorescent lamp 21 is formed into a small size, for example, with an axial length of about 21 cm and a width (major axis) direction of about 18 cm. The glass bulb 22 is formed into a flat shape with an oval longitudinal 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 cylindrical shape with an elliptical longitudinal section, and an upper surface 22a in the figure and a lower surface 22b in the figure face each other in the direction of its short axis a, and these upper and lower surfaces Both surfaces 22a and 22b are each formed into substantially flat surfaces.

Further, the glass bulb 22 has a pair of front and rear side surfaces 22C1 and a rear side surface 22d that face each other in the direction of the major axis, 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 the display panel 2a, the rear surface of the liquid crystal display panel can be completely illuminated 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.

The pair of metal caps 23a and 23b have annular fitting recesses 27a on their respective inner surfaces into which both opening ends of the glass bulb 22 are tightly fitted.

27b, respectively.

These fitting recesses 27a and 27b are metal caps 23.
It is formed by pressing the outer bottom surfaces of a and 23b inward in an oval shape.

For this purpose, oval outer recesses 28a, 28b that approximately fit the inner surface of the glass bulb 22 are formed on the outer bottom surfaces of the metal caps 23a, 23b, and the inner surfaces of these outer recesses 28a, 28b are oval. shaped electrode surface 29a,
It becomes 29b.

Next, a method for sealing a pair of metal caps 23a and 23b to both ends of the opening of the glass bulb 22 will be described.

First, as shown in Figure 3 (A),
Both ends of the opening are inserted into the fitting recesses 27a and 27b of the pair of metal caps 23a and 23b, respectively.

Next, when the pair of metal caps 23a and 23b are sequentially heated in the chamber 17 shown in FIG. 16 using a carbon heater or high frequency induction heating, the pair of metal caps 27a and 27b heated to a high temperature Both open ends of the glass bulb 22 that come into contact with the glass bulb 22 are melted.

However, as shown in FIGS. 3(B) and 3(C), the molten glass is restricted by the inner and outer circumferential walls of the fitting recesses 27a and 27b of the pair of metal caps 23a and 23b, respectively, so that the molten glass is 29a and 29b are prevented from hanging inward and covering part of them.

Therefore, as shown in FIG. 3(D), the electrode surfaces 29a of the pair of metal caps 23a, 23b.

It is possible to prevent the effective area of the electrode 29b from being reduced, and also to prevent its deformation.

As a result, stability of electrical characteristics such as discharge stability can be improved.

Further, as shown in FIGS. 3(B) and 3(C), the sealed end of the glass bulb 22 is connected to a pair of metal caps 23a and 2.
3b to both the inner and outer circumferential walls of the fitting recesses 27a and 27b,
Since the bonding area is expanded, the sealing strength can be improved.

In addition, as shown in FIG. 4, each metal cap 23a, 2
Metal plates such as nickel or aluminum may be fixed to the electrode surfaces 29a and 29b of 3b by spot welding or the like.In particular, if LaB6, Zr, etc. having a low work function are used as these metal plates, the cathode drop It is possible to keep the voltage low and improve lamp efficiency.

Next, the operation of the sixth embodiment will be explained.

First, when a required lamp voltage is applied from the lighting circuit 26 between the pair of metal caps 23a, 23b, the electrode surfaces 29 on both inner surfaces of the pair of metal caps 23a, 23b
A planar discharge occurs between a and 29b over almost the entire length in the major axis direction.

This planar discharge excites the mercury in the glass bulb 22,
Generates ultraviolet rays in a planar manner, and this ultraviolet rays
Fluorescent films 24a, 24 on the inner surfaces of upper and lower surfaces 22a, 22b of 2
While exciting almost the entire surface of b in a planar manner, both front and rear sides 2
Visible light is generated by exciting the fluorescent films 24 2c and 22d.

Since the film thickness of the fluorescent film 24a on the inner surface of the upper surface 22a of the glass bulb 22 is thinner than the film thickness of the fluorescent film 24b on the inner surface of the lower surface 22b, the fluorescent film 24a on the upper surface 22a side
The amount of light transmitted through a and outputted to the outside increases, and the light generated in the fluorescent film 24b on the lower surface 22b side is also transmitted through the upper surface 22a and outputted to the outside, and this upper surface 22a is formed as a light emitting surface. .

Therefore, since the flat fluorescent lamp 22 itself is configured as a surface light source that emits light from the light emitting surface 22a with substantially the same luminance over the entire surface, the conventional reflector 2 shown in FIG.
The second diffuser plate 4.5 can be omitted.

Further, since the metal caps 23a and 23b are used in common as the sealing member of the glass bulb 22 and the electrodes, the number of parts can be further reduced.

Therefore, by arranging a liquid crystal display panel (not shown) in parallel on the upper surface 22a of the flat fluorescent lamp 22 configured as described above, it is possible to illuminate the back surface of the liquid crystal display panel almost entirely and with equal brightness. can.

Therefore, according to this embodiment, the conventional reflector 2 and the first,
By omitting the second diffuser plates 4 and 5, it is possible to improve luminance efficiency and reduce the number of parts, resulting in smaller size, lighter weight, and thinner shape.
By flattening the glass bulb 22, it is possible to further reduce the thickness of the glass bulb 22, and also to reduce costs.

In particular, by making the flat fluorescent lamp 21 smaller, lighter, and thinner, it is possible to use the flat fluorescent lamp 21, for example, as a backlight for an ultra-compact liquid crystal display panel in a color electronic viewfinder for a camera-integrated video camera. can.

Incidentally, the flat fluorescent lamp 21 of this embodiment has an axial length of 21 m+a, a width direction (major axis) length of 18 w, an argon gas filling pressure of 100 fort, and a lamp voltage of 120 m.
(2) When the lamp current is 4.8 mA, the brightness of this flat fluorescent lamp 21 is 3500 cd/nf, and the degree of uniformity is 0. It was 43 win, /+ax.

The flat fluorescent lamp 21 of this embodiment has a fitting recess 27a into which both opening ends of the glass bulb 22 are fitted into the pair of metal caps 23a and 23b.

27b, these fitting recesses 27a, 27b and both ends of the opening of the glass bulb 22 are joined on both the inner and outer circumferential surfaces, increasing the joint area and improving the sealing strength between the two.

Further, both opening ends of the glass bulb 22 are recesses 27a into which a pair of metal caps 23a and 23b are fitted.

Since the glass is heated and melted while it is inserted into the metal caps 27b, it is possible to prevent the molten glass from dripping onto the electrode surfaces 29a and 29b of the pair of metal caps 23a and 23b, thereby improving electrical properties such as discharge stability. can increase the stability of

Since the flat fluorescent lamp 21 of this embodiment has outer recesses 28a and 28b formed on the outer bottom surfaces of the pair of metal caps 23a and 23b which also serve as electrodes, the lighting device 31 shown in FIGS. 5 and 7 .41, it can be connected to the lighting circuit without using lead wires or the like.

As shown in FIG. 5, the lighting device 31 has a pair of left and right locking claws 33a, 33b erected on the back surface (top surface in FIG. 5) of the mounting surface of a lighting circuit board 32 on which lighting circuit components (not shown) are mounted. are doing.

The pair of locking claws 33a and 33b are made of a conductive and combustible metal plate or the like, and are erected on the circuit board 32 at a distance approximately corresponding to the axial length of the flat fluorescent lamp 21. , their lower end surfaces are respectively connected to electrical output terminals (not shown) of the lighting circuit board 32, so that a required lamp voltage is applied.

Therefore, as shown in FIG. 5, when the fluorescent lamp 21 is inserted between the pair of locking claws 33a and 33b along its longer diameter direction, the upper ends of the lamps expand outward as shown by the arrows in the figure. bend it to guide its insertion.

Therefore, when the fluorescent lamp 21 is further pushed in, as shown in FIG. Recesses 28a and 28b of 23b
The connector is inserted into the connector removably and electrically contacted at the same time.

For this purpose, the flat fluorescent lamp 21 can be attached to and removed from the lighting circuit board 32 with a single touch using the pair of locking claws 33a and 33b, and at the same time, it is electrically connected to the lighting circuit of the lighting circuit board 32.

Therefore, according to this lighting device 31, the flat fluorescent lamp 21 can be held and fixed very easily, and the flat fluorescent lamp 21 can be held and fixed very easily.
1 and the lighting circuit board 32 can be integrated into a unit and electrically connected to the lighting circuit.

On the other hand, the lighting device 41 shown in FIG.
1 placed horizontally, the fitting body 4 fits into the pair of left and right outer surface recesses 28a and 28b of the fluorescent lamp 21.
3a and 43b are fixed on the lighting circuit board 42.

At least one of the pair of fitting bodies 43a, 43b is configured such that the distal end thereof can move forward and backward in the axial direction.

In other words, at least one of the fitting bodies 43a and 43b is the eighth
As shown in the figure, at the tip of the inner cylinder 44a, which has a cylindrical shape with a lid,
A covered cylindrical outer cylinder 44b is fitted onto the outside so as to be slidable in the axial direction, and a spring member 45 is built into the outer cylinder 44b.
4b is configured so that it can move forward and backward in its axial direction.

Therefore, when fixing the flat fluorescent lamp 21 on the lighting circuit board 42, first, one of the outer recesses, for example 28a, of the flat fluorescent lamp 21 is connected to the retractable, for example, fitting body 43.
a, further push the flat fluorescent lamp 21 toward the fitting body 43a, and retreat the outer tube 44b shown in FIG. 8 toward the inner tube 44a.

In this way, a slight gap is formed between the outer bottom surface of the other metal cap 23b of the flat fluorescent lamp 21 and the inner surface of the other fitting body 43b, and the other metal cap 23b is pushed toward the circuit board 42 side, and the other metal cap 23b is pushed into the other recess 28b. When the fitting body 43b is fitted,
Due to the spring restoring force of the spring member 45 inside the outer cylinder 44b, the flat fluorescent lamp 21 is pushed toward the other fitting body 43b, and the outer cylinder 4
4b expands.

Therefore, with this lighting device 41 as well, the flat fluorescent lamp 21 can be attached to and removed from the lighting circuit board 42 with one touch, and at the same time, the lighting circuit can be electrically connected.

FIG. 9 shows a lighting device 51 that holds the flat fluorescent lamp 11 shown in FIG. 14 and is electrically connected to a lighting circuit.

This is a pair of holding members 53a that elastically sandwich the pair of metal caps 13a, 13b of the flat fluorescent lamp 11 in the axial direction from the outer surfaces of the pair of outward flanges 15a, 15b on the lighting circuit board 52 on which the lighting circuit is mounted. , 53b are fixed.

The pair of holding members 53a and 53b are formed by bending an elastic metal band plate into a substantially flat W-shape, and as shown in FIG. A bottom convex portion 54a is curved to contact and support the bottom surfaces of the pair of metal caps 13a and 13b from below.

Further, the pair of holding members 53a and 53b are a pair of left and right convex portions 54b that protrude inwardly from both sides of the flat fluorescent lamp 11 in the longitudinal direction so as to sandwich and hold the same.

54c are formed on both left and right sides of the upper end of the W-shaped opening so as to curve inward.

Further, the upper ends of the openings of the holding members 53a and 53b are curved so as to expand outward, so as to guide the insertion of the flat fluorescent lamp 11.

Therefore, the flat fluorescent lamp 11 is connected to the lighting circuit board 52.
The pair of holding members 53a, 53 are placed horizontally against the
By pushing between b, a pair of metal caps 23
a, 23b are supported at three points in the radial direction, and a pair of holding members 53a.

53b, the axial direction is held between them, and the holding thereof is ensured.

Further, the pair of holding members 53a and 53b are attached to the lighting circuit board 5.
Since it is electrically connected to a pair of electrical output terminals (not shown) of the lighting circuit of No. 2, the -pair of metal caps No. 1
3a and 13b are elastically held by a pair of holding members 53a and 53b, and at the same time are electrically connected to a lighting circuit.

Therefore, with this lighting device 51 as well, the flat fluorescent lamp 11 can be attached and detached from the lighting circuit board 52 with one touch, and both can be integrated into a unit.

The pair of holding members 53a and 53b are formed into a U-shape as shown in FIG.
It may be formed so that it can be held vertically with respect to the lighting circuit board 52.

The lighting device 61 shown in FIG. 12(A) is a flat fluorescent lamp 1.
A curved plate 62 having elasticity that curves outward is fixed to the outer bottom surface of one of the pair of metal caps 13g and 13b, while the curved plate 62 is fixed on one surface of the lighting circuit board 63 forming the lighting circuit. A pair of receivers 64a and 64b are fixed to sandwich and hold the outer bottom surface of the metal cap 13b and the outer bottom surface of the other metal cap 13b.

The pair of receivers 64a and 64b are made of a conductive material and have, for example, a U-shaped cross section, and one end thereof is electrically connected to a pair of electric output terminals of a lighting circuit (not shown) on the lighting circuit board 63.

Therefore, when fixing the flat fluorescent lamp 11 on the circuit board 63, first, the curved plate 62 of the flat fluorescent lamp 11 is strongly pressed against the inner surface of one of the receivers 64a to elastically deform it, and the outer bottom surface of the other metal cap 13b is Other receiver 6
4b, the flat fluorescent lamp 11 is elastically held in the axial direction by the pair of receivers 64a and 64b, and at the same time is electrically connected to the lighting circuit board.

Therefore, with this lighting device 61 as well, the flat fluorescent lamp 11 can be attached and detached from the lighting circuit board 63 with one touch, and both can be integrated into a unit.

A lighting device 71 shown in FIG. 12(B) is a flat fluorescent lamp 1.
The outer bottom surface of the pair of metal caps 13a, 13b of 1 has a pair of metal rod-shaped support legs 72a, 7 at the center thereof.
2b is fixed by welding or the like so as to protrude outward in the short diameter direction of the flat fluorescent lamp 11, for example.

On the other hand, the lighting circuit board 73 forming the lighting circuit has mounting holes 74 a and 74 b into which the tips of the pair of support legs 72 a and 72 b are fitted, respectively.
The inner peripheral surfaces of these pair of mounting holes 74a and 74b are electrically connected to the electrical output terminals of the lighting circuit, respectively.

Therefore, by fitting the tips of the pair of support legs 72a, 72b into the pair of mounting holes 74a, 74b of the lighting circuit board 73 and soldering them, the flat fluorescent lamp 1
1 can be fixed on the lighting circuit board 73 and electrically connected to the lighting circuit at the same time.

Above the flat fluorescent lamp 11 fixed on the lighting circuit board 73, there is a liquid crystal display (L).
CD) panels can be placed close together and used as a surface light source to illuminate almost the entire surface with equal brightness.

The pair of support legs 72a and 72b are fixed to the flat fluorescent lamp 11 so as to protrude upward and downward from the flat fluorescent lamp 11, as indicated by broken lines in the figure.

Moreover, since each of the flat fluorescent lamps 11.21 has a front and a back surface with the light emitting surfaces 12a and 22a as the front surface, it is also possible to erroneously read the front and back sides of each of the lighting devices 31.21. 41°51.61.71
A so-called foolproof means may be provided to prevent the device from being attached to the device.

〔Effect of the invention〕

As explained above, the present invention provides a fitting recess that surrounds both the inner and outer circumferential surfaces of the glass bulb by fitting both axial ends of the glass bulb into a sealing member that seals both ends of the axial opening of the glass bulb. Therefore, when the opening ends of this glass bulb are heated and melted, the molten glass drips onto the inner surfaces of the pair of sealing members that form the electrode surfaces, reducing the effective electrode surface area and changing the shape of the exposed surface. can be prevented.

Therefore, it is possible to improve the stability of electrical characteristics such as discharge stability caused by deformation of the shape of the exposed electrode surface and reduction of the effective electrode surface area.

Further, since both ends of the axial opening of the glass bulb are fitted into the fitting recess, the sealing strength between the two can be improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the flat fluorescent lamp according to the present invention, FIG. 2 is an exploded perspective view of the embodiment shown in FIG. 1, and FIG. FIG. 3(B) is a partial vertical sectional view showing a state in which both axial ends of the glass bulb of the example shown are fitted into the fitting recesses of a pair of metal caps. FIG. A vertical cross-sectional view showing the state of sealing with the cap, Figure 3 (C) is C in Figure 3 (B).
FIG. 3(D) is a sectional view taken along line D-D in FIG. 3(B), FIG.
The figure is a front view showing the lighting device for the flat fluorescent lamp shown in FIG. 1, FIG. 6 is a partially enlarged view of FIG. 5, and FIG. 7 is a front view of the lighting device for the flat fluorescent lamp 21 shown in FIG. 8 is a partially enlarged vertical sectional view of FIG. 7, FIG. 9 is a perspective view of the lighting device for the flat fluorescent lamp shown in FIG. 14, and FIG. 11 is a front view showing a modified example of the holding member shown in FIG. 10, and FIGS. 12(A) and (B) are views of the fluorescent lamp shown in FIG. 15. A perspective view of another lighting device, FIG. 13 is an exploded perspective view of a conventional lighting device, FIG. 14 is a perspective view of a flat fluorescent lamp, FIG. 15 is an exploded perspective view of the flat fluorescent lamp shown in FIG. The figure is a front view showing the state of vacuum sealing of the flat fluorescent lamp etc. shown in Fig. 14, and Fig. 17 is a partial longitudinal section showing the state of fitting the glass bulb and metal cap of the flat fluorescent lamp shown in Fig. 14. Figure 18 (A) (B)
is a cross-sectional view taken along the line X■-X■ in FIG. 17. 11.21... flat fluorescent lamp, 12.22... glass bulb, 13 a, 13 b, 23 a,
23 b... A pair of metal caps (sealing member that also serves as an electrode), 14.24... Fluorescent film, 16.26...
- Lighting circuit, 27a, 27b = fitting recess, 28a, 2
8b - External recess.

Claims (1)

[Claims] A phosphor is coated on the inner surface of a flat cylindrical glass bulb,
Both axial opening ends of this bulb are respectively fitted into the fitting recesses of a pair of sealing members made of conductive material to surround both the inner and outer circumferential surfaces of both opening ends, and are heat-fused to seal these opening ends. 1. A flat fluorescent lamp characterized in that the bulb is hermetically sealed, mercury and rare gas are sealed in the bulb, and the pair of sealing members are used as electrodes.