JP3101333B2 - Flat fluorescent lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat fluorescent lamp suitable for use as a back light source of a liquid crystal display device such as a liquid crystal panel for a vehicle, a liquid crystal TV and a liquid crystal projection.

[0002]

2. Description of the Related Art A conventional flat-type fluorescent lamp excites a phosphor with an electron beam to emit light, and is excellent in luminance control and temperature characteristics. FIG. 3 shows a sectional perspective view of the flat fluorescent lamp. The structure will be described with reference to the drawings. 1 is a front panel, 2 is a rear panel, and 3a, 3b and 3c are frame glasses. Then, a phosphor 4 formed on the inner surface of the front panel 1 and a metal back anode 5 formed by vapor deposition of aluminum on the phosphor 4 are arranged. An end of the anode 5 is provided with a carbon paste or the like. High pressure supply unit (not shown)
Is arranged.

[0003] Further, in this glass container, linear cathodes 7, 7, ..., supported by a plurality of columns 6, 6, ..., are provided.
There is a pair of grid meshes 8a and 8b that are grid electrodes. The grid mesh 8a controls the amount of electrons supplied from the linear cathode 7 to the phosphor 4 to which a high voltage is applied, and the grid mesh 8a receives a grid mesh 8a from the anode 5 to enable cutoff. A low voltage is also applied. A back electrode 9 is formed on the inner surface of the back panel 2.

Here, for convenience, the trajectories of electrons in eight directions a to h generated from a linear cathode as shown in FIG. 4 will be considered. FIG. 5 shows a sectional view of a main part of a flat fluorescent lamp. By the back electrode 9, electrons are also generated from the linear cathodes 7, 7,... In the direction of d, e, f of the back panel 2, and the electrons are attracted to the back electrode side. The electron orbit expands. Electrons having directional components of c and g are electrons c1, toward the front panel side.
g1 and electrons c2 and g2 toward the rear panel. The electrons heading to the front panel side are grid mesh 8
The light is diffused by a and 8b and reaches the anode 5. The energy of the arrived electrons passes through the metal back anode 5 to excite the phosphor 4 to emit light with high luminance.

[0005]

In a flat-type fluorescent lamp having a rear electrode 9 and a flat-type electronic device such as a flat display, the electron beam is more intense than a flat-type electronic device having no back-electrode 9. Although it spreads, its effect is not enough, and c1 and g1 are also weaker than a, b and h, so that the phosphor above the linear cathode 7 is inevitably bright and the space between the cathodes 7 and 7 is dark. And uneven brightness.

The unevenness of the shape of the back electrode can be changed to change the potential distribution of the portion formed by the back electrode and the grid mesh to improve the luminance unevenness. However, the uneven back electrode is formed on the back panel. Forming is difficult in manufacturing.

The present invention has been made in view of the above points, and has been made in consideration of the above-mentioned problems. By changing the shape of the back electrode 9, it is possible to improve the luminance unevenness caused by the linear cathode without lowering the overall luminance. It is an object of the present invention to provide a compact fluorescent lamp.

[0008]

According to the present invention, there is provided a flat fluorescent lamp comprising: a glass container comprising a front panel, a rear panel and a frame glass; a phosphor formed on an inner surface of the front panel;
A plurality of linear cathodes arranged in parallel with the front panel and supported by a support member; a back electrode arranged on the inner surface of the rear panel in parallel with the linear cathodes in a stripe pattern; And a grid mesh disposed between the linear cathode and the front panel, wherein the rear electrode is a first rear electrode disposed between the linear cathodes, and directly below the linear cathodes. And a second back electrode disposed on
It is characterized in that control is performed so that a higher voltage is applied to the first back electrode than to the second back electrode.

[0009]

[0010]

[0011]

According to the present invention, as described above, since the back electrode is formed in a stripe shape, the electrons generated from the line-shaped cathode spread and spread on the line-shaped cathode as compared with the case where the back electrode continuously spreads over the entire surface. The resulting luminance unevenness can be improved without lowering the overall luminance.

[0012]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a main part of a flat fluorescent lamp according to an embodiment of the present invention. As shown in FIG. 1, the back electrode 9 has a stripe shape parallel to the linear cathodes 7, 7,... And is formed on the inner surface of the rear panel 2 at the same pitch between the linear cathodes 7, 7,. A pulse voltage is applied to the linear cathodes 7, 7,... To generate thermoelectrons. The generated electrons are applied to the striped back electrode 9 of the present invention.
The electrons of a, b, and h which are drawn toward the front panel have wider electron trajectories than the conventional example shown in FIG. The electrons c and g are also drawn to the front panel side, and some of the electrons d1 and f1 of d and f are also drawn to the front panel side. As a result, the number of electrons between the linear cathodes 7, 7 is increased, and the uneven brightness is improved.

FIG. 2 shows another embodiment of the present invention. The structure of the back electrode is such that first back electrodes 9a, 9a,... Arranged between the linear cathodes 7, 7 and second back electrodes 9b, 9b,. And the first
By controlling the voltage applied to the back electrode 9a and the voltage applied to the second back electrode 9b, dimming can be performed more precisely than in the above-described embodiment. For example, if the voltage applied to the first back electrode 9a is increased, the electrons emitted from the linear cathode 7 are spread, and if the voltage of the second back electrode 9b is reduced, the spread is reduced.

Further, in the above embodiment, the electrons in the e-direction were hardly generated due to the structure. However, in the present embodiment, the electrons in the e-direction are generated. It increases from the case of the embodiment. By making the voltage applied to the first back electrode 9a higher than the voltage applied to the second back electrode 9b, the thermoelectrons generated by the second back electrode 9b are drawn to the first back electrode 9a side. And a part of it goes to the front panel side.

The widths of the first back electrode and the second back electrode may not be the same. For example, when the width of the first back electrode is smaller than the width of the second back electrode, the same effect can be obtained by making the voltage value applied to the first back electrode higher than when the width is equal.

The voltage applied to each electrode is desirably in the order of: anode 5 grid mesh 8b grid mesh 8a first back electrode 9a linear cathode 7, 7,... Second back electrode 9b. In some cases, may be replaced.

[0018]

Since the present invention is configured as described above, the trajectory of electrons generated from the linear cathode to the front panel side can be expanded, and more electrons generated on the back electrode side can be generated on the front panel side. Can be drawn to.
Therefore, it is possible not only to improve the luminance unevenness caused by the linear cathode, in which the upper part of the linear cathode of the flat fluorescent lamp emits light brightly, and the luminance of the upper part between the cathodes is reduced. The brightness of the type fluorescent lamp itself can be improved.

Further, by controlling the voltage applied to the first back electrode and the voltage applied to the second back electrode, more precise light control can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment according to the present invention.

FIG. 2 is a sectional view of a main part of another embodiment according to the present invention.

FIG. 3 is a sectional perspective view of a conventional flat fluorescent lamp.

FIG. 4 is an electron orbit model diagram.

FIG. 5 is a sectional view of a main part of a conventional flat fluorescent lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front panel 2 Back panel 3a, 3b, 3c Frame glass 4 Phosphor 5 Anode 6 Support 7 Line cathode 8a, 8b Grid mesh 9, 9a, 9b Back electrode

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Yagi 2-18 Keihanhondori, Moriguchi City Sanyo Electric Co., Ltd. (56) References JP-A-1-253150 (JP, A) JP-A-63-304555 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 63/06 H01J 61/30

Claims (1)

(57) [Claims] 1. A glass container comprising a front panel, a rear panel, and a frame glass, a phosphor formed on an inner surface of the front panel, and a plurality of phosphors arranged in parallel to the front panel and supported by a support member. A flat fluorescent lamp comprising: a linear cathode; a back electrode disposed on the inner surface of the rear panel in parallel with the linear cathode in a stripe form; and a grid mesh disposed between the linear cathode and the front panel. Wherein the back electrode comprises a first back electrode disposed between the linear cathodes, and a second back electrode disposed immediately below the linear cathodes, wherein the first rear electrode Wherein a control is performed to apply a higher voltage than the second back electrode.