JPH0789478B2 - Electric field discharge type 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 fluorescent lamp, and more particularly to a fluorescent lamp which is thin and has a planar light emitting surface so as to be suitable for back lighting of a liquid crystal display. .

[0002]

2. Description of the Related Art FIG. 7 shows an example of the structure of a conventional fluorescent lamp 90 having a flat light emitting surface. A pair of glass substrates 91 each having a fluorescent film 91a coated on one surface are shown in FIG. The pair of electrodes 9 are made to face each other so that the fluorescent film 91a faces the inside, and the cross section between the glass substrates 91 is substantially U-shaped and substantially corresponds to the length of one side of the glass substrate 91.
2 is provided to seal the periphery, and mercury (vapor), argon gas, etc. are sealed inside.

[0003]

However, since the above-described conventional fluorescent lamp 90 is flattened, the electrode 9 is different from that of a conventional fluorescent lamp such as a straight tube type.
The area of 2 becomes enormous, and when a voltage is applied between the electrodes 92, the planar glow discharge instantaneously shifts to a linear arc discharge, and the entire surface of the fluorescent lamp 90 does not emit light.

As a solution to the above, this fluorescent lamp 9
A lighting method is adopted in which a voltage is intermittently applied in a pulsed manner at a time interval of 0 for the duration of the glow discharge described above, but the duration of the glow discharge is 5 μm.
The lighting circuit of the fluorescent lamp 90 becomes very complicated because it is extremely short, about s, and the fluctuation factors such as the ambient temperature must be taken into consideration.
All in all, this kind of lighting system has a problem of being expensive.

Further, since the flattening means is merely a lateral extension of a conventional fluorescent lamp, it is no different from the conventional straight tube type fluorescent lamp in the thickness direction. Therefore, it is necessary to increase the thickness of the glass to withstand external pressure for thinning, which is one of the greatest objectives when flattening, and it is very difficult to reduce the thickness and weight. There was a problem that the target could not be reached, and the solution to these problems became an issue.

[0006]

As a concrete means for solving the above-mentioned conventional problems, the present invention is such that an electrode film is formed on the inner surfaces of two glass substrates facing each other, and the electrodes are At least one of the films is a transparent electrode film to serve as a light emitting surface, and is a transparent dielectric layer except a portion on the inner surface side of the electrode film and where the electrode film is an external electrode portion.
Phosphor layers are sequentially laminated, and the two glass substrates are sealed with a frit glass sealing portion around the outer electrode portions at appropriate intervals with the outer electrode portions being displaced, and a rare gas inside,
Another object of the present invention is to solve the above-mentioned conventional problems by providing an electric field discharge type flat fluorescent lamp characterized by containing a rare gas and mercury.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail based on an embodiment shown in the drawings. Reference numeral 1 in FIGS. 1 and 2 is a flat fluorescent lamp according to the present invention. First, the structure of the flat fluorescent lamp 1 will be described. The flat fluorescent lamp 1 is basically formed by two glass substrates 2 facing each other at appropriate intervals.
In each of the above, the electrode film 3 is formed in advance on one surface by means such as printing or vapor deposition.

At this time, the electrode film 3 is basically I
Although it is assumed that the flat fluorescent lamp 1 is formed of a transparent conductive member such as a TO film, it is clear that only the light emission from one side is used when the flat fluorescent lamp 1 is in use, for example, for back lighting of a liquid crystal display. In some cases, the electrode film 3 formed on one of the glass substrates 2 is made transparent,
The glass substrate 2 side is used as a light emitting surface, and the electrode film 3 formed on the other glass substrate 2 is made opaque to improve conductivity or durability as will be described later. Good as a thing.

A transparent dielectric film 4 is formed on the surface side of the electrode film 3, and at this time, the electrode film 3 in an appropriate range is transparent on one end side of the glass substrate 2. The body film 4 is not covered, and the portion of the electrode film 3 which is not covered is defined as the external electrode portion 3a.

It is assumed that a phosphor film 5 is further formed on the surface side of the transparent dielectric film 4, and the two glass substrates 2 having the above-described structure have the respective phosphor film 5 portions. The edges of the portions where the glass substrates 2 face each other are made to face each other, that is, the electrode films 3 of the respective glass substrates 2 are made to face each other by displacing the portions that are the external electrode portions 3a to the outside. Is sealed by a sealing portion 6 made of frit glass, and a rare gas, or a rare gas and mercury are sealed inside the flat fluorescent lamp 1.

In the following, further details of the above configuration will be described. First, in the glass substrate 2, the surface on the side where the electrode film 3 is formed is previously made into a corrugated uneven surface, and The phosphor film 5 stacked via the electrode film 3 and the transparent dielectric film 4 may be substantially expanded in area to increase the amount of light, and the surface opposite to the above,
That is, it is also possible to make the light emission uniform by performing a matting treatment on the outer surface when the flat fluorescent lamp 1 is completed with fine unevenness called frost.

Further, in the electrode film 3, when it is clear in advance that only one glass substrate 2 side is the light emitting surface H as shown in FIG. 3, it is laid on the other glass substrate 2. It is not necessary to form the electrode film 3G to be transparent. In such a case, if the electrode film 3G is made of a getter material such as niobium, tantalum, or titanium, the vacuum degree in the flat fluorescent lamp 1 can be effectively maintained, and the life of the flat fluorescent lamp 1 can be extended. And will be.

Similarly, when the electrode film 3G may be opaque, the electrode film 3G may be formed as a light-reflecting surface by forming a member having excellent luster such as nickel. In this case, the back surface in the used state. The light emitted to the flat fluorescent lamp 1 is reflected by the light reflecting surface of the glossy surface and directed toward the light emitting surface, which is effective for improving the brightness of the flat fluorescent lamp 1. still,
At this time, if the electrode film 3G is formed of a member having excellent gloss such as titanium, the getter function and the light reflecting surface function can be obtained at the same time.

Next, the one glass substrate 2 side is the light emitting surface H.
In this case, the electrode film 3T (see FIG. 3) laid transparently on the one glass substrate 2 will be described. The electrode film 3T is formed by a known means such as an ITO film. However, the resistance value per unit area of the ITO film is relatively high, and the current value that can be passed is limited. For example, the amount of power supply at a position away from the position where the external electrode portion 3a is provided is insufficient to be dark. May occur.

In order to solve the above situation, in the present invention, as shown in FIG. 4, the above-mentioned transparent electrode film 3 is used.
For example, a structure is provided in which the auxiliary electrode film 7 in the form of a grid is provided on T, and if the auxiliary electrode film 7 is formed by the same means as the opaque electrode film 3G made of the metal member described above, the conductivity becomes Since it is remarkably excellent, even if it is formed to have an extremely narrow width, its purpose can be sufficiently achieved. Therefore, even if the auxiliary electrode film 7 is opaque, it has little influence on the light quantity of the flat fluorescent lamp 1. It becomes possible. The shape of the auxiliary electrode film 7 can be freely set to a shape other than the lattice shape shown in the figure, and the point is that the auxiliary electrode film 7 may have a shape capable of uniformly supplying electric power to the entire surface of the electrode film 3T.

Further, the transparent electrode film 3T formed of an ITO film or the like is poor in flexibility, and there is a property that cracks which easily cause conduction failure due to expansion and contraction of the glass substrate 2 due to temperature change are generated. Have In order to address the above, the present invention provides the electrode film 3 as shown in FIG.
Each T is formed into a mechanically independent unit, such as a grid, so that even if one unit cracks, it does not spread to other units, and each of the units is connected to the auxiliary electrode. It is also possible to electrically connect with the film 7 so that the entire unit has the function of the electrode film 3. The auxiliary electrode film 7 is formed of a getter material similarly to the electrode film 3G, and the dielectric film 4 is formed on the electrode film.
Even if the phosphor film 5 is removed, the auxiliary electrode film 7 is formed through the dielectric film 4 and electrically connected through the contact hole (not shown) provided in the dielectric film 4. You can do it.

Further, FIG. 6 illustrates the phosphor film 5 and, for example, when the flat fluorescent lamp 1 has only one surface as a light emitting surface, the phosphor film 5 is also formed on the glass substrate 2. It may be provided on only one side. This means that when only one surface is used as a light emitting surface, the light emitted from the phosphor film 5 on the back side is not emitted to the light emitting surface unless it passes through the phosphor film 5 on the front side.
Since the light is considerably attenuated at the time of this transmission, it does not substantially double, and therefore, when the brightness is not so required, it can be omitted practically without any trouble.

When only one surface is used as a light emitting surface as described above, the transparent dielectric film 4 on the back surface side becomes invisible from the light emitting surface side, so that the surface thereof has an amalgam shape. If the mercury amalgam layer 8 is applied over the entire surface or in an appropriate range (see FIG. 2) by applying the above-mentioned mercury, only the rare gas should be enclosed inside when performing the sealing described below. Since a simple sealing means such as a method can be performed, the structure described above is provided and the manufacture of the flat fluorescent lamp 1 having no exhaust pipe is simplified. The mercury amalgam layer 8 is reduced to mercury by heating after the flat fluorescent lamp 1 is completed, so that the flat fluorescent lamp 1 turns into mercury vapor and contributes to discharge.

Finally, the structure of the sealing portion 6 will be described. The sealing portion 6 holds two glass substrates 2 at a predetermined interval, and the spacing is the unevenness of light emission. It is required to be uniform in terms of prevention of In view of the above, in the present invention, two glass substrates 2 can be easily formed by previously mixing the sealing portion spacer 9a such as glass beads having a predetermined diameter in the frit glass forming the sealing portion 6. It is possible to face each other at a predetermined interval and to seal them (see FIG. 2).

Further, the space between the two glass substrates 2 is maintained by
Substrate spacers 9b made of glass beads or the like may be dispersed between the glass substrates 2 (see FIG. 2). In this case, if a phosphor is applied to the substrate spacers 9b in advance, When the flat fluorescent lamp 1 is turned on,
The substrate portion spacer 9b also emits light, and prevents black spots and the like from occurring on the light emitting surface. It is also possible to use the sealing part spacer 9a and the substrate part spacer 9b together.

When the flat fluorescent lamp 1 constructed as described above is turned on, when a high frequency power of, for example, 50 KHz is applied from the external electrode portion 3a of the electrode film 3, both electrode films 3 facing each other are both capacitors. As a result, a high-frequency current due to an electric field flows between both electrode films 3 to cause discharge, and the phosphor film 5 is excited and emits light by ultraviolet rays generated by the movement of electrons at this time.

As is clear from the above description, in order to cause the electrode film 3 to have a remarkable capacitor-like action, the distance between the electrode films 3 should be as small as possible without causing dielectric breakdown. The flat fluorescent lamp 1 according to the present invention is also preferably narrower than 1 mm. At this time, the transparent dielectric layer 4 is effective in preventing the above-mentioned dielectric breakdown and, at the same time, extremely effective in making the discharge uniform.

This is effective in thinning the flat fluorescent lamp 1 as a result, and the efficiency of the flat fluorescent lamp 1 is reduced as the conventional construction is thinned. With the above configuration, the efficiency tends to increase as the device becomes thinner, and it is possible to provide a configuration that is essentially suitable for thinning. In addition, the fact that the lighting can be performed with the high frequency power as described above means that the lighting circuit is simplified, and the lighting circuit can be configured with a normal circuit configuration such as an oscillation circuit.

[0024]

As described above, according to the present invention, an electrode film, a transparent dielectric layer, and a phosphor layer are sequentially laminated on the inner surfaces of two glass substrates facing each other, and the two glass substrates are laminated. The substrate is a flat fluorescent lamp in which the periphery is sealed with a sealing portion at an appropriate interval, and the rare gas or the rare gas and mercury are sealed inside to form a flat fluorescent lamp. Even if the distance between the films is set as narrow as possible, that is, in other words, even if the distance between the two glass substrates is set to be narrow, it is assumed that the luminous efficiency does not decrease and the flat fluorescent lamp is made thinner. Therefore, when used as a backlight of a liquid crystal display, for example, it has an extremely excellent effect in achieving miniaturization and weight reduction of the entire device.

Secondly, with the above configuration,
The discharge in the fluorescent lamp is an electric field discharge that does not concentrate in a part by causing arc discharge or the like, for example, it is possible to light with a normal waveform such as a sine wave or a rectangular wave. It is possible to achieve simplification and to achieve an excellent effect in reducing the cost of the system.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an electric field discharge type flat fluorescent lamp according to the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a perspective view showing the main part of another embodiment of the present invention.

FIG. 5 is a perspective view showing another embodiment of the present invention as a main part.

FIG. 6 is a sectional view showing another embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 ... Flat fluorescent lamp 2 ... Glass substrate 3, 3G, 3T ... Electrode film 3a ... External electrode part 4 ... Transparent dielectric film 5 ... Phosphor film 6 ... Sealing part 7 ... Auxiliary electrode Membrane 8: Mercury amalgam layer 9a: Sealing part spacer 9b: Substrate part spacer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01J 61/28 L (72) Inventor Kazuki Kawasaki 2-17 Minami Eda, Midori-ku, Yokohama-shi, Kanagawa 8 (72) Inventor Yoshinori Kure 1178-2, Shinba-cho, Kohoku-ku, Yokohama-shi, Kanagawa

Claims (12)

[Claims] 1. An electrode film is formed on the inner surfaces of two glass substrates facing each other, and at least one of the electrode films is a transparent electrode film to serve as a light emitting surface, and the inner surface of the electrode film is further inside. A transparent dielectric layer and a phosphor layer are sequentially laminated on a portion other than the portion where the electrode film serves as an external electrode portion, and the two glass substrates are appropriately shifted with the external electrode portion portion shifted. A flat fluorescent lamp of an electric field discharge type, characterized in that the periphery is sealed at intervals with a sealing portion made of frit glass, and a rare gas or a rare gas and mercury are sealed inside. 2. The electric field discharge type flat fluorescent lamp according to claim 1, wherein the phosphor layer is provided on only one of the glass substrates. 3. The field discharge type flat fluorescent light according to claim 1, wherein one of the electrode films is formed of a getter material, and the dielectric layer and the fluorescent material layer thereon are removed. lamp. 4. The transparent electrode film of the electrode film is provided with an auxiliary electrode film in a strip shape or a grid shape so as to overlap the transparent electrode film to reduce the resistance. The electric field discharge type flat fluorescent lamp according to claim 1. 5. A transparent electrode of the electrode film, wherein the auxiliary electrode film is provided in a strip shape or a grid shape,
5. The field discharge type flat fluorescent light according to claim 4, wherein the transparent electrode film is divided into a plurality of blocks so as to be electrically connected and mechanically separated by the auxiliary electrode film. lamp. 6. The flat fluorescent lamp of the electric field discharge type according to claim 1, wherein a large number of irregularities are provided on the inner surface side of the glass substrate. 7. The method according to claim 1, wherein the outer surface side of the glass substrate is matt-treated.
The electric field discharge type flat fluorescent lamp described. 8. The electric field according to claim 1, wherein a mercury amalgam layer is provided on the dielectric layer provided on the glass substrate opposite to the light emitting surface. Discharge type flat fluorescent lamp. 9. The electric field discharge type flat surface according to claim 1, wherein the electrode film provided on the glass substrate opposite to the light emitting surface is formed as a light reflecting surface. Fluorescent lamp. 10. The sealing portion spacer made of glass beads or the like is mixed in the sealing portion, and the gap between the glass substrates is held by the sealing portion spacer. An electric field discharge type flat fluorescent lamp according to claim 9. 11. The substrate part spacer made of glass beads or the like is scattered between the two glass substrates, and the gap between the glass substrates is maintained by the substrate part spacer. An electric field discharge type flat fluorescent lamp according to claim 10. 12. The electric field discharge type flat fluorescent lamp according to claim 11, wherein the substrate spacer is coated with a phosphor.