JPH0747791Y2 - Flat fluorescent lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a planar fluorescent lamp, which is preferably used for a backlight of a surface emitting fluorescent lamp, such as a liquid crystal television or a liquid crystal display.

[Prior Art] Conventionally, as a flat fluorescent lamp used for a backlight of various liquid crystal display devices, a pair of glass substrates each having a phosphor film on one surface thereof are arranged substantially parallel to each other and are fluorescent. Arranged so that the body membrane is located inside, cells are formed by joining at the peripheral part via a spacer,
A pair of cold cathode electrodes are arranged to face each other on both sides in the cell,
A cell in which a gas containing a trace amount of mercury vapor is enclosed is disclosed in JP-A-1-231255. Then, by applying a voltage between the electrodes to discharge the mercury vapor, the mercury vapor is excited, and the generated ultraviolet rays excite the phosphor film to emit light. Here, as the glass substrate, a thin glass plate is used to reduce the weight of the fluorescent lamp, but there is a problem that the glass bends inward under a reduced pressure. In order to solve this, as disclosed in JP-A-63-232255 and JP-A-63-149059, there is one in which a reinforcing bar is inserted in the cell.

[Problems to be solved by the present invention] However, in the above-mentioned conventional technique, since the emission of the phosphor is prevented in the portion where the reinforcing bar is provided, a surface light source having uneven emission surface and uniform emission intensity is provided. There was a problem that I could not get it.

According to the present invention, the thickness of the central portion of the cell of the fluorescent lamp is such that even if the glass substrate is slightly recessed inside under the reduced pressure used,
It is intended to provide a fluorescent lamp in which a substantially uniform cell gap can be secured and the light emitting surface has no unevenness.

[Means for Solving the Problems] In the present invention, the periphery of the first and second glass substrates coated with a phosphor film on the inner surface is sealed with a spacer at intervals, and the inside of the sealed cell is formed. A fluorescent lamp in which a gas containing decompressed mercury vapor is filled, and a pair of cold cathodes are arranged to face each other.
In the flat fluorescent lamp, the thickness of the pair of spacers that determines the cell gap is larger in the peripheral portion than in the corner portion of the cell.

In the present invention, the distance between the inner surfaces of the first and second glass substrates of the fluorescent cell is called the cell gap.
The thickness of the at least one pair of facing spacers in the direction that determines the cell gap is determined so that the thickness of the peripheral portion of the light emitting surface is larger than the thickness of the corner portion of the light emitting surface. The cell formed by such a spacer may be a uniformly bright surface light source in which the cell gaps of the central portion, the peripheral portion and the corner portion of the light emitting surface are substantially constant in a state of being sealed at a reduced pressure suitable for light emission. it can. When the thickness of the peripheral portion of the spacer is a and the thickness of the corner portion of the spacer is b, the difference between a and b cannot always be uniquely determined by the thickness of the glass used and the size of the light emitting area. Diagonal length is 76mm (3 inch size)
When using a fluorescent lamp having a light emitting area of from 1 to 150 mm (6 inch size) and a glass substrate having a thickness of 1.1 to 2.3 mm, it is preferable that the thickness is larger than 0.016 mm and smaller than 0.15 mm.

The spacer for the fluorescent lamp of the present invention is not particularly limited as long as it is an electrically insulating material such as glass or ceramics, but glass processed to a predetermined size, especially float glass, is chemically strengthened to improve its mechanical strength. The one that is not subjected to the chemical strengthening treatment is used. Even if the spacer is integrally molded, 4
Two spacers may be glued to seal at the corners of the cell.

[Operation] At least one pair of spacers of the present invention that defines the cell gap of a fluorescent lamp has a thickness that defines the cell gap in the peripheral portion of the cell is larger than the thickness that defines the gap in the corner portion of the cell. Before the glass substrates are attached to each other by the spacers and put into a depressurized state, the cell gap is slightly larger in the central portion than in the peripheral portions or the corner portions. After that, when the cell is depressurized, the central portion of the glass substrate slightly bends inward due to atmospheric pressure, but since the amount of this deflection is corrected by the thickness difference of the spacer, the cell gap during lighting is It remains constant throughout.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view and a plan view of a flat fluorescent lamp of the present invention, FIG. 2 is a sketch of an embodiment of a spacer that can be suitably used in the flat fluorescent lamp of the present invention, and FIG. 1 is a main assembly view of a flat fluorescent lamp of the present invention. In FIG. 3, in the upper glass substrate 1 (first glass substrate), the spacer glass 4 and the lower glass substrate 9 (second glass substrate),
A low-pressure glass (hereinafter referred to as frit) is used as an adhesive to form a depressurized cell (enclosed with mercury and argon gas of 0.04 to 0.8 Pa).

The electrode 2 is welded to the lead piece 3 inside and is set to face the sealed space. The spacer glass 4 (shown in the sketch of FIG. 2 (a)) is notched at the center, and the exhaust pipe 6 is sealed by a frit there. As shown in FIG. 3, a mercury dispenser 8 is inserted in the exhaust pipe 6, and the spacer glass 4 is
A recess is provided so that the lead piece 3 can be set. The glass substrates 1 and 9 are coated with phosphors 10 and 11, respectively. The glass substrates 1 and 9 are bonded to the spacer glass 4 by the frit 5, and the exhaust pipe 6 is bonded to the spacer glass 4 and the glass substrates 1 and 9 by the frit 7.

Each part will be described in detail below.

(1) The upper glass substrate 1, the lower glass substrate 9 and the spacer glass 4 are made of float glass having a soda lime silica composition, and the upper glass substrate 1 and the lower glass substrate 9 are made of a 1.3 mm thick glass plate at 430 ° C. A tempered glass was obtained by immersing the molten salt in heated potassium nitrate for 1 hour. As the spacer glass 4, a pair of facing glass as shown in FIG. 2 (a) was used in which the cell gap was large in the cell peripheral portion. Here, the amount of deflection (difference in thickness), which is the difference between a and b, was 0.09 mm.

(2) The electrode 2 is made of nickel-plated stainless steel having a U-shaped cross section.

(3) The lead piece 3 is made of an oxidized 42Ni-6Cr-Fe alloy.

(4) The frits 5 and 7 are made of lead-containing glass in order to enable bonding with a low melting point.

(5) The exhaust pipe 6 is sealed after exhausting and enclosing argon gas, but lead-containing glass having a low melting point is used to facilitate the sealing.

(6) The mercury dispenser 8 uses a mercury compound that is inserted before sealing and decomposes into mercury by high-frequency heating after sealing.

(7) The phosphors 10 and 11 are applied to the respective inner surfaces of the glass substrate by screen printing. The phosphor is a three-wavelength type of R, G, and B, and each is appropriately blended and used. The diagonal length of the light emitting surface manufactured in this way is approximately
A 7.6 mm (3 inch size) fluorescent lamp is applied with a primary voltage of 9 V and a primary current of 0.22 A to the inverter, and a secondary voltage of 1200 V
(Peak-to-peak value), secondary current 6mA. The light emitting surface had a substantially uniform brightness. A fluorescent lamp was manufactured in the same manner except that the glass spacer shown in FIG. 2 (b) was used. In this case as well, a surface light source was obtained in which the emission brightness was substantially uniform and free of unevenness.

[Effect of the Invention] Since the fluorescent lamp of the present invention has a uniform light emission luminance over the entire light emitting surface, it can provide a uniform display when used as a backlight of a liquid crystal display cell or the like.

[Brief description of drawings]

FIG. 1 is a schematic plan view and a sectional view of a flat fluorescent lamp of the present invention, and FIG. 2 is a sketch of an embodiment of a spacer according to the present invention. FIG. 3 is a main assembly view of the flat fluorescent lamp of the present invention.

Claims (1)

[Scope of utility model registration request] 1. A first and second inner surface coated with a phosphor film.
The glass substrate is sealed around the glass substrate at intervals with a spacer, the sealed cell is filled with a gas containing decompressed mercury vapor, and a pair of cold cathodes are opposed to each other. In the flat fluorescent lamp, the thickness of the at least one pair of spacers facing each other is larger in the peripheral portion than in the corner portion of the cell.