JPH0388252A - Cold cathode fluorescent lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a cold cathode fluorescent lamp suitable for a backlight for illuminating the back side of a liquid crystal display panel, and in particular, relates to a cold cathode fluorescent lamp with an improved cold cathode. This invention relates to cold cathode fluorescent lamps.

(Prior Art) Conventionally, this type of cold cathode fluorescent lamp has a structure as shown in FIG.
For example, a pair of caps 3.degree. 3 on the left and right sides of the figure are externally fitted and fixed to both axial ends of a straight circular glass bulb 2, for example.

A pair of cap bottles 4.degree. 4 is installed on the outer end surface of each cap 3, while a flared glass stem 5, for example, is fixed to the inner end surface of each cap 3, respectively.

A pair of left and right cold cathodes 7 are erected on each stem 5 via a pair of wells 6.6, and these pairs of cold cathodes 7 face each other in the axial direction of the bulb 2.

The bulb 2 has a fluorescent film coated on its inner circumferential surface over the entire surface and over almost the entire length, and mercury and rare gas are sealed inside the bulb 2.

Each cold cathode 7 is made by bending a rectangular cold cathode plate 7a into an inverted V shape as shown in FIGS. , a pair of left and right cold cathodes 7,
7 are facing each other.

For this purpose, the head of the stem 5 (the upper end in FIG. 5(B)) is made to protrude into the inverted V-shaped opening end of each cold cathode plate 7a,
The overall size of these cold cathode plates 7a and stem 5 is reduced.

Further, each cold cathode 7 is supported by a pair of wells 6.6 at the left and right ends in the figure of the inverted V-shaped bent top of each cold cathode plate 7a, and these wells 6.6 are connected to each base. pin 4,4
are electrically connected to each other.

At the axially intermediate portion of each inverted V-shaped inclined surface of each cold cathode plate 7a, as shown in FIG. ) 9 is provided by pressure coating.

The getter 8 is made of, for example, an alloy of zirconium (Zr) and aluminum (AI), and is adapted to absorb impurity gas within the bulb 2. Further, the titanium-mercury 9 is adapted to release a required amount of mercury into the bulb 2.

(Problem to be Solved by the Invention) By the way, each cold cathode 7 emits electrode material from the cold cathode plate 7a during discharge, but a part of it is attached to the inner peripheral surface of the bulb 2 and causes tube wall blackening. arise.

In the conventional cold cathode fluorescent lamp 1 described above, the outer surface of the inverted V-shaped inclined surface of each cold cathode plate 7a faces inward (to the center) of the bulb 2, so that each The electrode material emitted from the inverted V-shaped outer surface of the cold cathode plate 7a in a substantially vertical direction is emitted and adheres to the inner circumferential surface of the bulb 2, causing blackening of the tube wall.

Therefore, there is a problem that this tube wall blackening occurs inside the bulb 2, that is, in the effective light emitting part that effectively emits the light emitted within the bulb 2, and reduces the brightness of this effective light emitting part.

In addition, when pinch-sealing each electrode sealing end of the bulb 2, for example, the flared stem 5 that supports the cold cathode 7 via the well 6.6 can be omitted; Since the cross-sectional shape inside the pinch seal end of No. 2 is approximately V-shaped, which is the opposite shape to the inverted V-shaped cold cathode 7, the installation space for the cold cathode 7 cannot be saved.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a cold cathode fluorescent lamp that can reduce the blackening of the tube wall of the effective light emitting part and increase its brightness.

[Structure of the invention]

(Means for Solving the Problems) The present invention has been made to solve the above problems, and
A cold cathode fluorescent lamp in which a pair of cold cathodes are each sealed in opposite ends of a bulb in the axial direction, and each of the pair of cold cathodes is formed in a shape that expands in the opposing direction. It is.

(Function) A pair of cold cathodes built into both ends of the valve in the axial direction,
Since it has a shape that expands in the opposite direction, its expanded outer surface faces the inner circumference of both axial ends of the bulb, but does not face the inside of the bulb, that is, the effective light emitting part.

Therefore, according to the present invention, the electrode material emitted from the expanded outer surfaces of the pair of cold cathodes is emitted onto the inner circumferential surface of both axial ends of the bulb and adheres to the tube wall, blackening the tube wall. Since the amount of radiation of the electrode material emitted toward the inner circumferential surface of the light emitting part is reduced, the amount of electrode material adhering to the effective light emitting part is reduced, and blackening of the tube wall is suppressed.

Therefore, it is possible to reduce the blackening of the tube wall in the effective light emitting part of the bulb and improve the brightness thereof.

(Embodiment) An embodiment of the present invention will be described below based on FIGS. Reference numeral 11 denotes a pair of left and right cold cathodes 13 and 13 by pinch-sealing both axial ends of a bulb 12 made of glass, for example, in the shape of a straight circular tube.
is hermetically sealed.

The bulb 12 has a fluorescent film (not shown) coated on its inner peripheral surface over almost its entire length, and mercury and rare gas are hermetically sealed therein.

A pair of left and right caps (not shown) are fitted onto the outer periphery of the pinch seal ends 12a, 12b of the valve 12 for sealing the pair of cold cathodes 13, 13.

Each cold cathode 13 is made by bending a rectangular cold cathode plate 13a, which is a thin metal plate, into a V-shape as shown in FIGS. 2(A) and 2(B). A getter 14 of the required width is provided at the middle part in the axial direction, and titanium-mercury (
TiHg) 15 is applied by pressure coating, and electrode material is applied to the parts other than these 14.15.

The getter 14 is made of, for example, an alloy of zirconium and aluminum, and absorbs impurity gas within the bulb 12, and the titanium-mercury 15 releases a required amount of mercury into the bulb 1.

A pair of left and right wells 16.16 are fixed to both sides in the width direction of the V-shaped tip of the cold cathode plate 13a, and these wells 16 are attached to the valve 12, as shown in FIG. 2(B).
The valve 12 is airtightly protruded from the mating surfaces of the pinch seal ends 12a at both axial ends of the valve 12, and is electrically fixed to a cap pin (not shown) implanted in a cap (not shown) by pressure welding or the like.

Therefore, the pair of cold cathodes 13.13 are expanded in the axial direction of the bulb 12 in the opposite direction as shown in FIG. The seal ends 12a and 12b are adapted to the approximately V-shaped vertical cross-sectional shape, respectively.

Therefore, the V-shaped outer surface of each cold cathode 13 is
The height ho of each cold cathode 13 can be reduced while facing the inner circumferential surface of the pinch seal 12a, which is an end portion of the bulb 12, instead of the axially intermediate portion thereof.

Next, the operation of this embodiment will be explained.

When a required lamp voltage is applied between the pair of cold cathodes 13.13 shown in FIG. 1, electrode material is released from each cold cathode 13, and a discharge occurs between the pair of cold cathodes 13. The fluorescent film is excited and the cold cathode fluorescent lamp 11 is turned on.

As shown in FIG. 2(B), since the V-shaped outer surface of each cold cathode 13 faces toward the pinch seal 12a side of the bulb 12, the electrode material emitted from the outer surface of the cold cathode 13 is As shown by the middle arrow, it is radiated vertically toward the inner circumferential surface of the electrode sealing end of the bulb 12, where it adheres and blackens the tube wall.

Therefore, according to this embodiment, the electrode material emitted from the outer surface of each cold cathode 13 is emitted toward the inner surface of the axial end of the bulb 12, and is emitted toward the inner surface of the bulb 12, that is, the inner peripheral surface of the effective light emitting section. Since the amount of electrode material emitted toward the tube is reduced, it is possible to prevent tube wall blackening due to adhesion of electrode material in the effective light emitting portion.

As a result, reduction in brightness due to tube wall blackening in the effective light emitting portion can be reduced.

Furthermore, according to this embodiment, each cold cathode 13 is closed in a V-shape corresponding to the reduced diameter inner peripheral surface of the pinch seal end 12a of the bulb 12, so that the height of the cold cathode 13 is increased. can be reduced to a minimum.

On the other hand, in the conventional cold cathode 7 shown in FIG. 6, it expands in an inverted V-shape, contrary to the V-shaped vertical section in the electrode sealed end of the bulb 12 shown in FIG. 2(B). Therefore, the height h of each cold cathode 7 becomes higher than the height ho of the cold cathode 13 of this embodiment.

That is, according to the cold cathode 13 of this embodiment, the height ho
By the amount that can be lowered, the axial length of the effective light emitting portion of the bulb 12 can be increased, and its brightness can also be increased.

Note that the present invention is not limited to the above embodiments,
For example, the cold cathode 13 may be configured as a plurality of blade-shaped cold cathodes 23 shown in FIG.
33 Any shape is acceptable as long as it expands in mutually opposing directions.

The cold cathode 23 having a plurality of blades has, for example, a lower end in the figure of five thin metal cold cathode plates 23a, and the other ends thereof are v.
The electrode is fixed in such a way that it expands in a letter-shaped manner to expand the electrode surface area.

The trumpet-shaped cold cathode 33 is a trumpet-shaped (cone-shaped) metal cold cathode plate 33a with a well 16 fixed to the reduced diameter end.

In these cold cathodes 23 and 33, similarly to the embodiment described above, it is possible to reduce the decrease in brightness due to the blackening of the tube wall of the effective light emitting part of the bulb 12, and to increase the length of the effective light emitting part.

〔Effect of the invention〕

As explained above, in the present invention, the shape of the pair of cold cathodes housed in both ends of the bulb in the axial direction is formed so as to expand in the opposite direction, so that the expanded outer surface is aligned with the axis of the bulb. It faces toward the inner circumferential surface of both end portions, and does not face the inner circumferential surface of the central portion of the bulb, that is, the effective light emitting portion.

Therefore, the electrode material emitted from the expanded outer surfaces of the pair of cold cathodes adheres to the inner circumferential surfaces of both axial ends of the bulb and causes tube wall blackening, but it is emitted to the inner circumferential surface of the effective light emitting part and does not adhere. It is possible to reduce the blackening of the tube wall, and it is possible to prevent a reduction in brightness due to the tube wall blackening of the effective light emitting portion.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of an embodiment of the cold cathode fluorescent lamp according to the present invention, FIG. 2(A) is a perspective view of the cold cathode shown in FIG. 3(A) and 2(B) are partially enlarged vertical cross-sectional views of the electrode sealed end shown in the figure.
Each perspective view showing a modified example of the cold cathode shown in the figure, No. 4
The figure is a partially cutaway front view showing the overall configuration of a conventional cold cathode fluorescent lamp, FIG. 5(A) is a perspective view of the conventional cold cathode shown in FIG. Side view of Figure 5 (A),
FIG. 6 is an enlarged longitudinal sectional view of the electrode sealed end shown in FIG. 4. 11...Cold cathode fluorescent lamp, 12...Bulb, 12
a...Pinch seal part, 13...Cold cathode, 13a.
...Cold cathode plate, 23...Multi-blade-shaped cold cathode, 33.
...Trumpet-shaped cold cathode. Figure 1 CB) Figure 2 (A) (B) II'': Figure J Figure 4

Claims (1)

[Claims] In a cold cathode fluorescent lamp in which a pair of cold cathodes are sealed in opposite ends of a bulb in opposite directions, each of the pair of cold cathodes is formed in a shape that expands in the opposite direction. A cold cathode fluorescent lamp featuring