WO2002017351A1

WO2002017351A1 - Flat lamp

Info

Publication number: WO2002017351A1
Application number: PCT/KR2001/001423
Authority: WO
Inventors: Hong-Ju Ha
Original assignee: Ha Hong Ju
Priority date: 2000-08-25
Filing date: 2001-08-23
Publication date: 2002-02-28
Also published as: KR20020016379A; KR100749167B1

Abstract

The present invention relates to a flat lamp. The flat lamp of the present invention is characterized in that an electric discharge space is defined between two sheets of glass corresponding to upper and lower substrates by means of bar-shspaed spacers and electrodes for inducing the electric discharge are formed at side walls of the spacers. According to the flat lamp of the present invention constructed as such, it can be utilized as a unidirectional or bidirectional light source. In particular, since the flat lamp generated light having uniform intensity throughout an entire large area thereof, there are advantages in that is is highly bright, it can be conveniently manufactured, and its manufacturing costs can be reduced.

Description

FLAT LAMP

Technical Field

The present invention relates to a flat lamp for emitting light as a surface unit.

Background Art

A light source originates from an incandescent illumination which has been developed in the latter half of the 19th century. The principle of the incandescent illumination is that electric current flows through a filament in a glass bulb in which inert gas is contained or which is in a vacuum state. The filament is rapidly heated and starts to emit incandescent light at about 900 °C . When a temperature of the filament reaches an operating temperature, i.e. 2500-2700 °C, the filament emits a typical "white" light with an optimal flux. It is a fluorescent lamp widely used at present in the home and company that has been further developed from the white light source. The fluorescent lamp is included in a low-pressure electric discharge light source. In such fluorescent lamp, electric discharge takes place within a glass tube in which krypton or argon gas is injected and sealed and of which an inner surface is coated with mixed fluorescent materials. Due to the flow of the electric current between both electrodes of the fluorescent lamp, the gas within the lamp emits invisible bluish green light. The ultraviolet rays emitted as such are alternately transmitted to the fluorescent coating surface such that the lamp emits light.

All the light sources, which have been developed into such various kinds, have started to be developed from a point light source.

The point light source means that light is emitted from a point, as can be seen from the terminology thereof. For example, in case of the fluorescent lamp, the light is emitted even between the respective points. It is a line light source that is further developed from here. That is, a line itself becomes a light source. Now, it is a surface light source for generating light having the same intensity thereof throughout one surface that has not yet been explained.

The surface light source is constructed to emit the light from the entire one surface which constitutes the light source. Thus, in case of the surface light source, a shadow of the surface and a projected shadow thereof appear palely to such an extent that they are not visible to a human eye. Further, color distortion thereof is relatively low. That is, the surface light source allows an entire space to be uniformly illuminated, has a low color distortion, and allows a person in the space to feel cheerful.

If the surface light source rather than the line light source is installed in a place such as a hospital where psychological action exerts great influence on the patient, an atmosphere in a corridor or room of the hospital will be greatly changed.

Further, a neon sign commonly used is an example of the line light source. The neon sign which is often used at the present is a line neon sign. That is, an advertisement pattern is displayed in a state where only edges of the neon sign emit light. Thus, assuming that the advertisement pattern such as a letter or symbol to be advertised is a "circle," light is emitted from only a circumference of the "circle" rather than an entire area of the "circle" in order to display the "circle."

Therefore, it is very difficult to precisely display the advertisement pattern desired by a user through the line neon sign, and there is also a limitation on the advertisement pattern to be expressed. Further, since manufacture of the line neon sign for displaying the advertisement pattern requires human's manual works, it is difficult to mass-produce it. Thus, there is a problem in that the production costs may be increased.

Accordingly, if the surface light source, which can display the advertisement pattern as a surface unit, is employed in the neon sign, more effective neon sign structure can be obtained.

As a result, the surface light source which can emit the light having the same intensity throughout a large surface may be applied to various fields. In the future, progress and development of the surface light source are inevitable. Disclosure of Invention

Accordingly, an object of the present invention is to provide a structure of a flat lamp which can emit light having the same intensity throughout a surface by means of electric discharge. A flat lamp of the present invention for achieving the above object comprises an upper substrate; a lower glass substrate sealed with a bottom surface of the upper glass substrate; and a plurality of spacers which are installed between the bottom surface of the upper glass substrate and a top surface of the lower glass substrate to define an electric discharge space therebetween, and each of which includes electrode portions for inducing electric discharge thereon. Preferably, each of the spacers takes the shape of a bar. Preferably, each of the electrode portions formed on the spacers includes an electrode for inducing the electric discharge, and a dielectric layer formed on the electrode. Preferably, the electrodes are formed on side walls of the spacers such that the electric discharge is induced between the opposite electrode portions.

Preferably, each of the electrode portions further comprises a protective layer formed on the dielectric layer.

Preferably, the flat lamp of the present invention further comprises fluorescent layers defined within the electric discharge space.

Preferably, the fluorescent layers are formed on the bottom surface of the upper glass substrate and/or the top surface of the lower glass substrate. .

Brief Description of Drawings FIG. 1 is a front view of a flat lamp according to the present invention.

FIG. 2 is a plan view showing a structure of a lower substrate structure of the flat lamp according to the present invention.

FIG. 3 is a sectional view showing a structure of an upper substrate structure of the flat lamp according to the present invention. FIG. 4 is a plan view showing a structure of the upper substrate of the flat lamp according to the present invention.

FIG. 5 is an exemplary view showing spacers to form electrode portions of the flat lamp according to the present invention.

FIGS. 6 to 8 are block diagrams illustrating processes of manufacturing the flat lamp according to the present invention.

FIG. 9 is a view showing another embodiment of the flat lamp according to the present invention.

Best Mode for Carrying Out the Invention Hereinafter, a flat lamp according to the present invention will be described with reference to the accompanying drawings.

The flat lamp of the present invention emits light having the same intensity throughout a surface. Further, the flat lamp of the present invention generates the light by means of electric discharge. Thus, according to the flat lamp of the present invention, the electric discharge for generating visible rays takes place between adjacent surfaces.

FIG. 1 is a front view of the flat lamp according to the present invention. FIG. 2 is a plan view of the flat lamp according to the present invention.

The flat lamp of the present invention comprises upper and lower substrates 9, 2 for transmitting light generated through the electric discharge, and spacers 1 installed between the upper and lower substrates 9, 2 for forming an electric discharge space therebetween. Thus, it is preferred that the upper and lower substrates 9, 2 be made of transparent glass materials having high light transmissivity. Each of the spacers 1 is constructed by a bar-shaped member, and may be made of glass material. It is prefeπed that an interval between the upper and lower substrates 9, 2 defined by the spacer 1 be set to about a predetermined value (0.5 - 3 mm). Thus, the height of the spacers 1 is closely correlated with the predetermined interval related to the formation of the electric discharge space. Further, the spacers 1 are composed of plural spacers which are generally arranged uniformly side by side such that the predetermined electric discharge space can be uniformly defined between the upper and lower substrates 9, 2. Thus, the spacers 1 installed on the lower substrate 2 are shown in the plan view of FIG. 2. That is, the bar-shaped spacers 1 are placed over some length on the lower substrate 2. . ^■

Although it is not shown in these figures, in order to seal the electric discharge space formed between the upper and lower substrates 9, 2 to be isolated from the exterior, a sealed portion is arranged at perimeter portions of the upper and lower substrates 9, 2. The sealed portion is a portion for defining the electric discharge space as an internal isolated space. Discharge gas is injected into the electric discharge space sealed as such, in which the electric discharge takes place when electric voltage is applied thereto.

In practice, the sealed portion may be constructed by applying material in the form of paste, which is obtained by mixing a powdered low-melting-point glass and synthetic resin material, along the perimeter portions, or by printing it to have a predetermined thickness thereon. The sealed portion is formed at the final stage after all the elements of the light source have been formed on the upper and lower substrates and the spacers.

After a single flat lamp has been completed through the sealing process, a control circuit (not shown) is connected to the flat lamp such that electric power can be supplied to electrodes formed in the spacers from the outside. That is, when the electric power is applied to the electrodes by means of the control circuit, the discharge gas is discharged in the electric discharge space.

The spacers 1 of the present invention are characterized in that they are installed between the upper and lower substrates 9, 2 for defining the electric discharge space. More specifically, the spacers 1 are characterized in that electrode portions for inducing the electric discharge are formed at side walls of the spacers 1.

Each of the electrode portions formed at the side walls la of the spacers 1 is composed of an electrode 3 formed directly at the side wall la of the spacer 1, a dielectric layer 5 formed on the electrode 3, and a protective layer 7 formed on the dielectric layer 5. At this time, the protective layer is formed to protect the dielectric layer. Thus, in a case where it is not necessary to form the dielectric layer in the electrode or to protect the dielectric layer, the protective layer need not be formed. A high conductive metal electrode or a transparent electrode such as an indium tin oxide (ITO) electrode may be utilized as the electrode 3. The electrode 3 may be formed at a portion of the side wall la as shown in FIG. 1, or may be formed at an entire region of the side wall. Anyway, the electrode 3 is manufactured at the side wall of the spacer 1 in the form of a surface. The dielectric layer 5 is formed to preserve produced charges such that a continuous electric discharge is maintained, and the protective layer 7 is formed to protect the dielectric layer 5 upon electric discharge.

The electrode portion manufactured as such is further formed at the other side wall lb of the spacer 1 to have the same structure. Thus, the electric discharge takes place between the opposite electrode portions positioned between the adjacent spacers.

Further, fluorescent layers 11 are formed on a bottom surface of the upper substrate 9 of the present invention. Each of the fluorescent layers 11 is patterned between the adjacent spacers 1. FIG. 3 is a sectional view of the upper substrate of the flat lamp of the present invention, and FIG. 4 is a plan view thereof.

That is, the flat lamp according to the present invention is constructed such that a fluorescent material for determining a color of the flat lamp is applied to the upper substrate 9 and the fluorescent material is formed between the adjacent spacers 1. Further, the fluorescent material may be applied to an entire surface of the upper substrate 9. If the fluorescent material is applied to the entire surface of the substrate, it is not necessary to perform an alignment process when installing the upper and lower substrates and the spacers therebetween.

Furthermore, the fluorescent layer 11 may be formed on a top surface of the lower substrate 1. As shown in FIG. 9, the fluorescent layer 11 may be formed on both the bottom surface of the upper substrate 9 and the top surface of the lower substrate 1. At this time, if the fluorescent layer formed at the upper substrate 9 is applied at a small thickness thereof to have high light transmissivity whereas the fluorescent layer formed on the lower substrate 1 is applied at a large thickness thereof to have high light reflectance, efficiency of the light source can be improved. Next, a process of manufacturing the flat lamp of the present invention having the above structure will be explained.

FIG. 5 is an exemplary view showing the spacers with the electrode portions formed at the side walls of the spacers in the flat lamp according to the present invention. FIGS. 6 to 8 are process charts for illustrating processes of manufacturing the flat lamp according to the present invention.

A process of forming the electrode portions for inducing the electric discharge at the side walls of the bar-shaped spacers according to the features of the present invention is first performed. In step 100, a plurality of the bar-shaped spacers 1, each of which has diameter and length thereof suitable for forming the electric discharge space, are prepared between the lower and upper substrates 2, 9. Then, the prepared spacers 1 are arranged side by side in a state where the side walls la thereof are directed upwardly (step 103). That is, the plurality of the spacers 1 are arranged as shown in FIG. 5.

Desired electrode patterns are simultaneously formed onto the side walls of the plurality of the spacers 1 arranged side by side as such (step 106). Then, the electrodes 3 are formed onto the side walls of the plural spacers 1 through a fritting process in accordance with the formed patterns (step 109). Alternatively, the electrodes may be formed through a thin-film process. That is, all processes of manufacturing general electrodes may be utilized for manufacturing the electrodes of the present invention.

If the electrodes 3 are formed on the side walls of the plural spacers 1 in step 109, desired patterns of the dielectric layers are simultaneously formed on the side walls of the spacers arranged side by side, and then, the dielectric layers 5 are formed on the electrodes 3 (steps 112 and 115).

In step 115, the electrodes 3 are formed on the side walls of the plural spacers 1 and the dielectric layers 5 are formed on the electrodes 3. Thus, since the plural spacers are arranged side by side, the electrodes and the dielectric layers are simultaneously formed on the side walls of the spacers 1.

Then, the protective layers 7 are formed on the dielectric layers 5 (step 118). Consequently, the electrode portions to be formed on the side walls of the spacers are completed (step 121).

Next, the opposite side walls lb of the spacers 1, in which the electrode portions have already been formed on the side walls la, are directed upwardly by rotating the spacers 180 degrees. Thereafter, the process of forming the electrode portions though steps 106 to 121 is repeated (step 124).

If the process of step 124 is completed, the process of forming the electrode portions for inducing the electric discharge at the both side walls of the spacers 1 is finished (step 127).

Next, two substrates each of which has a predetermined size corresponding to the size of a panel to be formed are prepared and cleaned (step 200). In general, the substrates are constructed by glass substrates.

The patterns of the fluorescent layers are formed on one of the cleaned substrates (step 203). The fluorescent layers 11 will be formed between the adjacent bar-shaped spacers, as shown in FIG. 1. Thus, the patterns of the fluorescent layers made in step 203 should be formed in accordance with the above condition.

If the patterns of the fluorescent layers are formed in step 203, arbitrary fluorescent materials for determining colors of the flat lamp are printed onto the patterns to completely form the fluorescent layers (step 206). A red fluorescent material will be printed if a red flat lamp is to be formed, whereas a green fluorescent material will be printed if a green flat lamp is to be formed.

As stated above, in the present invention, the upper substrate 9 is utilized as a supporting substrate with the fluorescent layers 11 formed thereon. However, the fluorescent layers 11 may be formed on either the upper substrate or the lower substrate.

Further, the fluorescent layers may be formed on all the upper and lower substrates as shown in FIG. 9. The arrangement of the fluorescent layers is appropriately selected in accordance with size and usage of the flat lamp to be manufactured.

Furthermore, the fluorescent layers may be formed on an entire surface of the substrate. In such a case, an alignment process is unnecessary.

The upper substrate 9 with the fluorescent layers 11 formed thereon, the spacers 1 with the electrode portions formed at the side walls thereof, and another cleaned lower substrate 2 are prepared through the above processes.

Next, processes of installing the spacers 1 between the lower and upper substrates 2, 9 and sealing the substrates will be performed.

That is, the plural spacers 1 with the electrode portions formed therein are ananged at predetermined positions on the lower substrate 2 (step 300). Thus, the positions on the . lower substrate 2 where the spacers 1 will be installed should be beforehand determined. At this time, the spacers 1 are arranged such that surfaces thereof with the electrode portions formed thereon can be positioned toward lateral sides thereof. Thus, the electrode portions formed at the left side walls of the respective spacers 1 face the electrode portions formed at the right side walls of the other spacers which are located at the left sides of the spacers 1. Further, the electrode portions formed at the right side walls of the spacers 1 face the electrode portions formed at the left side walls of the other spacers which are located at the right sides of the spacers 1. As viewed from above, the structure in which the spacers 1 are installed on the lower substrate 2 in step 300 is shown in FIG. 2.

Then, the upper substrate 9 with the fluorescent layers 11 formed thereon is placed onto the lower substrate 2 with the spacers 1 installed thereon. At this time, the surface with the fluorescent layers 11 formed thereon is directed downwardly.

Thereafter, the alignment for the lower and upper substrates is adjusted such that the fluorescent layers 11 can be positioned between the respective adjacent spacers (step 303). In step 303, the spacers 1 are installed on the lower substrate 2 and the upper substrate 9 is placed onto the spacers 1. This is shown in FIG. 1 as viewed from front.

If the alignment between the upper and lower substrates 9, 2 is adjusted as such, the upper and lower substrates are sealed with each other by applying a sealing material thereto (step 306). When sealing the substrates in step 306, impurities are removed from the electric discharge space and an extra space into which discharge gas is injected is beforehand formed.

Next, if the impurities including impure gas residing in the sealed electric discharge space are removed (step 309) and the discharge gas is injected therein (step 312), the flat lamp is completed.

Since a predetermined voltage is applied to the flat lamp constructed as such by means of the control circuit (not shown) connected to the outside, the electric discharge takes place between the electrodes facing each other. That is, the electrodes can, in fact, be electrically connected from the outside of the upper substrate 9 and the lower substrate 2 closely fixed to the upper substrate.

Thus, the electric discharge takes place between the opposite electrodes among the electrodes formed on the side walls of the spacers 1. Consequently, the opposite electrodes have electric potentials different from each other such that the electric discharge can be induced therebetween.

The electric discharge induced between the electrodes according to the present invention takes place at entire surfaces of the side walls of the bar-shaped spacers 1 at the same time, and also takes place simultaneously at all electrodes installed in the panel. Thus, the ultraviolet rays having the same intensity are produced, throughout the panel, by the electric discharge. The ultraviolet rays generated as such excite the fluorescent layers 11 to be transformed into the visible rays which are in turn transmitted through the upper substrate 9.

The structure in which the electrode portions for inducing the electric discharge are formed at the side walls of the bar-shaped spacers is very suitable for the large flat lamp. That is, according to the present invention, since the electrodes are formed on the plural spacers, respectively, to induce the electric discharge simultaneously so that the light having the almost same intensity can be generated throughout the entire surface of the large flat lamp, the flat lamp having an ultra large area thereof can be obtained. As described above, it is apparent that the basic feature of the present invention is to define the electric discharge space between two sheets of glass corresponding to the upper and lower substrates by means of the bar-shaped spacers and to form the electrodes for inducing the electric discharge at the side walls of the spacers. Various changes and modifications can be made by those skilled in the art without departing from the technical spirit and scope of the present invention.

Industrial Applicability

As described above, it will be understood that the present invention has the following advantages.

First, the flat lamp of the present invention can generate the light having the same intensity throughout the large surface thereof. Thus, the flat lamp of the present invention can generate highly bright light as compared with the conventional point light source or line light source. In particular, the flat lamp of the present invention can be utilized as a unidirectional or bidirectional light source.

Further, according to the present invention, the electrodes for inducing the electric discharge are substantially formed on the side walls of the spacers which are installed between the upper and lower substrates to define the electric discharge space. Thus, since deformation of the upper and lower substrates due to formation of the light source elements cannot be produced when the upper and lower substrates are sealed, the alignment of the substrates can be easily adjusted.

Furthermore, according to the present invention, discharge induction can be easily performed, the electric discharge can be induced by the low electric power, and the light source for generating the light having the same intensity throughout the large panel can be obtained.

Claims

1. A flat lamp, comprising: an upper glass substrate; a lower glass substrate sealed with a bottom surface of the upper glass substrate; and a plurality of spacers which are installed between the bottom surface of the upper glass substrate and a top surface of the lower glass substrate to define an electric discharge space therebetween, and each of which includes electrode portions for inducing electric discharge thereon.

2. The flat lamp as claimed in claim 1, wherein each of the spacers takes the shape of a bar.

3. The flat lamp as claimed in claim 1, wherein each of the electrode portions formed on the spacers includes an electrode for inducing the electric discharge, and a dielectric layer formed on the electrode.

4. The flat lamp as claimed in any one of claims 1 to 3, wherein the electrodes are formed on side walls of the spacers such that the electric discharge is induced between the opposite electrode portions.

5. The flat lamp as claimed in claim 4, wherein each of the electrode portions further comprises a protective layer formed on the dielectric layer.

6. The flat lamp as claimed in claim 4, further comprising fluorescent layers defined within the electric discharge space.

7. The flat lamp as claimed in claim 6, wherein the fluorescent layers are formed on the bottom surface of the upper glass substrate and/or the top surface of the lower glass substrate.