JPH0650624B2 - Flat fluorescent lamp - Google Patents

Description

The present invention relates to a flat fluorescent lamp suitable as a backlight for a liquid crystal display device or a liquid crystal TV device in a word processor, a personal computer or the like.

(B) Conventional technology Since liquid crystal panels are advantageous in that they are light and thin and consume little power, they are widely used as display devices such as personal computers or word processors in addition to liquid crystal TVs. On the other hand, since the liquid crystal itself does not emit light, it is necessary to use a flat fluorescent lamp as described in Japanese Utility Model Publication No. 54-111985 (93D311).

In addition, the liquid crystal panel has become larger in size in recent years and, for example, A4 size twine has come to be used, and it becomes necessary to increase the size of a flat fluorescent lamp used in such a large liquid crystal panel. It was However, if the glass container is made large, it is necessary to use thick glass in order to prevent the implosion due to the atmospheric pressure, and there is a drawback that it becomes difficult to reduce the weight and the thickness.

In order to solve the above-mentioned drawbacks, the applicant of the present invention previously filed Japanese Patent Application No.
Japanese Patent No. 1-54194 proposes a flat fluorescent lamp in which a reinforcing glass is provided between a pair of upper and lower flat glass plates which face each other to increase the withstand pressure and enable a reduction in thickness.

Incidentally, soda glass which is relatively inexpensive is conventionally used for the above-mentioned flat fluorescent lamp. As shown by the solid line in FIG. 8, the transmittance characteristics of this soda glass are visible light (3800 Å ~
It shows a very high transmittance in the range of 6800Å), but it is not completely flat and contains 0.1% or more of Fe ₂ O ₃ so that the transmittance is highest near green (5500Å) and slightly lower at other wavelengths. There is.

Therefore, on the light emitting surface of the flat fluorescent lamp, since the light is transmitted through the glass for a longer distance in the portion where the reinforcing glass is located, the luminance is slightly lower than that in the other portions and the greenish light is emitted. Become. Therefore, when it is used as a backlight for a color liquid crystal display, there is a drawback that uneven brightness occurs at a specific portion on the screen and the color is modulated to green.

(C) Problems to be Solved by the Invention The present invention has been made in view of the above points, and provides a flat fluorescent lamp in which uneven brightness or color tone change does not occur on the light emitting surface even when a reinforcing glass is used. To do.

(D) Means for Solving Problems The present invention uses, as the reinforcing glass, glass having substantially flat transmittance characteristics in the visible light range.

(E) Action Since the light transmitted through the reinforcing glass does not change in color tone by the above-described means, there is no change in color tone between the light passing through the flat glass and the light passing through the flat glass and the reinforcing glass.

(F) Embodiment One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a flat fluorescent lamp according to this embodiment,
2 (a), (b) and (c) are plan views of the same planar fluorescent lamp, respectively.
It is a sectional view taken along the line A-A 'and a sectional view taken along the line BB'.

In the figure, (1) and (2) are upper and lower flat glass sheets of A4 size (278 mm × 192 mm) each having a fluorescent film (3) and (4) formed on the inner surface thereof, and each of the fluorescent films is a slit-shaped glass. Coater (5)
It is divided into 3 by (6). Further, the upper surface of the upper flat glass (1) is roughened, and the lower surface of the lower flat glass (2) corresponds to the uncoated portions (6) and (6), and is wider than this uncoated portion. Reflective films (7) and (7) made of aluminum foil are formed.
(8) is a frame-shaped frame glass that holds the upper and lower flat glasses at a predetermined interval, and constitutes a glass container together with the upper and lower flat glasses. (9) (9) is a pair of discharge poles with a U-shaped cross section, and auxiliary electrodes (9a) (9a) (9a) (9
are formed respectively, and U-shaped notches (9b) (9b) are formed on the extension of the position of the uncoated portion. (1
Reference numerals 0), (10) ... Lead pieces each having an L-shaped cross section and connected to the auxiliary electrodes by spot welding and projecting to the outside. The lead pieces also have a function of mechanically supporting the discharge pole in addition to an electrical function. Have. (11) (11) is a prismatic reinforcing glass having a height equal to the gap between the upper and lower flat glass and prevents implosion. In addition, this reinforced glass is provided with notches (9b) (9b) ...
The end part fits in and the upper and lower surfaces are uncoated parts.
(5) (6) ... Face and contact. Further, the surface of this reinforced glass is roughened as described later.

Moreover, white plate glass is used for the reinforcing glass (11) in the present embodiment. This white glass has a Fe ₂ O ₃ content of 0.02
The transmittance characteristic is approximately equal to or less than%, and as shown by the dotted line in FIG. 8, it shows a high transmittance in the visible light region and is substantially flat.

Therefore, the light transmitted through the white plate glass is not modulated in a specific color.

In addition, it is obvious that the reinforcing glass may be made of quartz glass, crystal glass, or the like having a low Fe ₂ O ₃ content and a transmittance characteristic that is substantially flat in the visible light region.

Further, (12) is a chip tube in which the inside of the glass container is exhausted and argon gas and mercury are made to flow in, and then the tip is sealed by heat fusion.

Next, a procedure for assembling the flat fluorescent lamp will be described.

First, the upper flat glass whose outer surface has been roughened beforehand (1)
And a fluorescent film (3) leaving an uncoated portion on each inner surface of the lower flat glass (2) on which a reflective film (7) is formed at a predetermined position on the outer surface in advance.
Screen print (4).

Further, a pair of discharge electrodes (9) and (9) on the lower flat glass (2) and a pair of reinforcing glasses fitted to the notches (9b) (9b) of the discharge electrodes as shown in FIG. (11) Place (11) at a predetermined position. In addition, the lead pieces (10) (10) are fixed to the auxiliary electrodes (9a) (9a) on both sides of the discharge electrode by spot welding in advance and on the surface of the reinforcing glass (11) (11). Is roughened.

Next, the frame glass (8) and the chip tube (12) on the lower flat glass (2).
And place the upper flat glass (1) together with the fritted glass,
A sealed glass container is formed by heat fusion.

Finally, the air in the container is evacuated through the chip tube (12), and argon gas and mercury are allowed to flow in, and the tip is heat-sealed to seal it.

Mechanical support of the reinforced glass (11) (11) in the above-mentioned container is performed only by fitting into the notch (9b) as shown in FIG. 3, and the upper and lower flat glass (1) (2) In addition, since it is not necessary to fix it with the fritted glass, uneven brightness due to protrusion of the fritted glass does not occur.

Next, FIG. 4 shows an enlarged cross-sectional view of the reinforced glass (11) in this example. The upper and lower surfaces of the reinforced glass (11) are located facing the uncoated portions (5) and (6) of the upper and lower flat glass (1) and (2), respectively, and the uncoated lower flat glass (2) is uncoated. A reflection film (7) is formed on the lower surface at a position corresponding to the portion (6). Therefore, the light which is incident on the reinforcing glass (11), is diffusely reflected by the side wall, and is directed upward is transmitted through the non-coated portion (5) and the upper flat glass (1) and radiated outward. In addition, the light reflected downward does not apply to the uncoated area below.
The light passes through (6) and the lower flat glass (2), is reflected by the reflective film (7) and goes upward, and is transmitted through the upper flat glass (1) and radiated outward as in the above.

Further, the surface of the reinforcing glass (11) has a particle size of 7.9 μm to 40 μm.
Roughened with a μm abrasive. Therefore, the light incident on the reinforcing glass (11) is diffusely reflected on the side wall, and the uncoated part
(5) Since more light goes to (5), the decrease in brightness or the uneven brightness due to the use of the reinforcing glass (11) is extremely reduced.

Further, the upper surface of the upper flat glass (1) is similarly roughened. Therefore, the reinforcing glass (1
Even if there is a slight difference in the brightness between the 1) part and the other part, the boundary is blurred, so that the uneven brightness is further suppressed.

FIG. 5 shows another embodiment of the reinforcing glass. Since the reinforcing glass (11) in this example has the fluorescent film (12) formed on its side surface, the reinforcing glass (11) itself emits light, and the uncoated portion
More light is emitted to the outside through (5) and the upper flat glass (1).

Next, FIGS. 6 and 7 show another embodiment of the discharge cathode and the reinforced glass. In FIG. 6, a convex fitting part (9c) is formed on the discharge pole (9) by press working, and the fitting step (9c) has a stepped part (9c) at the tip of the reinforcing glass (11). 11a) is inserted and the position is fixed. The stepped portion (11a) is formed to have a thickness equal to or greater than the plate thickness of the discharge electrode (9) so that the fitting portion (9c) does not directly contact the upper and lower flat glass.

Also, in FIG. 7, the discharge pole (9) has a U-shaped second
The auxiliary electrode (9d) is welded. This second auxiliary electrode (9
In d), the distance between the pair of protruding pieces is formed to be the same as or slightly smaller than the thickness of the reinforcing glass (11).
Is elastically clamped.

(G) Effect of the Invention As described above, according to the present invention, even if the reinforcing glass is used, uneven brightness and color tone change do not occur on the light emitting surface.
It is effective as a back light of a display device such as a V, a personal computer or a word processor.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a flat fluorescent lamp according to an embodiment of the present invention, and FIGS. 2 (a), (b), and (c) are plan views of the flat fluorescent lamp, AA 'cross-sectional view, and FIG. BB 'sectional view, FIG. 3 is a perspective view of an essential part showing a mounting structure of the reinforcing glass, FIG. 4 is an enlarged sectional view of the reinforcing glass, and FIG. 5 is an enlarged sectional view showing another embodiment of the reinforcing glass. , FIG. 6 and FIG. 7 are enlarged cross-sectional views showing another embodiment of the mounting structure of the reinforcing glass, and FIG. 8 is a view showing the transmittance characteristic of the glass. (1) (2) …… Upper and lower flat glass, (3) (4) …… Fluorescent film, (5) (6)
…… Uncoated area, (7) …… Reflective film, (8) …… Frame glass, (9)
(9) …… Discharge electrode, (11) (11) …… Reinforced glass.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Katsumi Terada Inventor Katsumi Terada 2-18 Keihan Hon-dori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. Electric Co., Ltd.

Claims (3)

[Claims] 1. A pair of flat glass plates having a fluorescent film formed on the inner surface thereof have a height substantially equal to the distance between the pair of discharge electrodes and the pair of flat glass plates in a glass container facing each other with a predetermined space. A flat fluorescent lamp in which a reinforcing glass is arranged, wherein the reinforcing glass is a glass having substantially flat transmittance characteristics in the visible light range. 2. The flat fluorescent lamp according to claim 1, wherein the reinforcing glass is white plate glass. 3. The flat fluorescent lamp according to claim 1, wherein the reinforcing glass is quartz glass.