KR20100012310A - Circular type of mercury free flat light source structure - Google Patents

Abstract

PURPOSE: A flat fluorescent structure of circular type is provided to maintain uniform and stable discharge even when the flat fluorescent structure is formed into a shape of circle and ellipse. CONSTITUTION: A flat fluorescent structure of circular type comprises: an upper plate(110) composed of transparent material of circular type; a lower plate(120) separated from the upper plate with an interval; and a supporting member(130) isolating the upper plate from the lower plate. Discharge gas forms a discharge space by pressure.

Description

Circular type of mercury free flat light source structure}

The present invention relates to a surface light source structure, and more particularly in a mercury-free surface light source structure using a plasma discharge, even if the surface light source structure is formed in a circular or elliptical surface light source that can maintain a uniform and stable discharge It relates to a structure and a manufacturing method.

The surface light source has various application possibilities in a backlight unit (BLU) or a lighting fixture of a passive light emitting display device such as an LCD. However, in the related art, it is difficult to properly configure a surface light source having sufficient brightness and light efficiency. Therefore, a plurality of line light sources and / or point light sources such as fluorescent lamps and LEDs are superimposed and additional optical devices such as diffuser plates and reflecting plates are utilized. Often used after converting to a surface light source.

By the way, in the case of the surface light source converted in this way, the efficiency is drastically reduced, and the manufacturing cost is increased due to the need for ancillary parts to convert to the surface light source. In addition, since the converted surface light source as described above is made by assembling a plurality of light sources, it is difficult to perform partial light emission or luminance control of a predetermined region selected in the secondary space. Therefore, it is possible to develop a surface light source device capable of front emission by itself, active operation such as brightness adjustment within a short time such as one frame level (typically 16.67.ms) of TV video signal, and partial light emission of a certain area. need.

In addition, conventional surface light sources such as fluorescent lamps capable of top emission have used a gas mainly containing mercury as a discharge gas. This is because mercury has excellent discharge characteristics and provides a stable driving voltage margin. However, mercury is expected to be limited in its use in lighting, etc. as an environmentally regulated material. If the temperature of the lamp is low, driving is difficult and efficiency is low. Therefore, development of the surface light source in which discharge gas of mercury is used is also required.

1 is a view schematically showing a surface light source according to the prior art using a mercury-free discharge gas. The surface light source 100 according to the prior art includes an upper plate 10, a lower plate 20, and a partition wall 30, and a voltage is applied to a pair of electrodes X and Y adjacent to a discharge space formed by them. By applying, an electric field is induced in the discharge space to generate a plasma. Ultraviolet (UV) light emitted from the plasma activates the phosphors 18 and 24 applied around the discharge space to emit visible light. In particular, as shown, the case of using the electrodes (X, Y) covered with a dielectric layer inside the discharge space is called a discharge mechanism of the DBD (Dielectric Barrier Discharge) method. Is applied to both electrodes X and Y to drive the surface light source 100. Generally, a driving waveform used to drive the surface light source 100 is illustrated in FIG. 2.

In order to form the surface light source as described above, the partition 30 is formed between the upper plate 10 and the lower plate 20 made of a material such as glass or silica, and a discharge gas is inserted thereinto, and then the upper plate ( 10) and the outer portion of the lower plate 20 is sealed from the outside air. The ends of the electrodes (X, Y) are projected to the end of the surface light source 100 in an appropriate manner so that an electrical connection can be made with an external drive circuit.

Prior to bonding the upper plate 10 and the lower plate 20, the fluorescent layers 18 and 24 are formed at appropriate positions. If necessary, the reflective film layer 22 may be formed so that light can be emitted to one side. As the discharge gas, a gas containing Xe for emitting excitation paper vacuum ultraviolet rays is used, and if necessary, a mixed gas further including an inert gas such as He, Ne, Ar, Kr, or the like is used.

Here, the voltage of the application pulse (that is, the discharge start voltage) that causes the discharge to start is mainly determined by the distance between the electrodes and the pressure. Assuming that the discharge gap (distance between electrodes) of the surface light source is long enough to sufficiently utilize an effective positive column region for glow discharge, the discharge start voltage is mainly determined by the pressure and composition of the gas as follows. Is determined.

V _f = B pd / {ln ( pd ) + ln (A / (ln (1 / γ + 1))}

A, B: Constant according to the type of gas

pd : Discharge gas pressure x discharge gap (distance)

γ : Secondary electron emission coefficient by ion on the surface of cathode surface

3A to 3D show changes over time of the discharge state in the surface light source of the prior art. When an appropriate voltage is applied between the electrodes protected by the dielectric layer, partial discharge starts as shown in FIG. 3A. When the voltage is applied for a sufficient time, as shown in FIG. 3B, a thin band-shaped initial discharge path is shown between the two electrodes. (discharge path) is formed. When the applied voltage is increased after the initial discharge path is formed, the discharge path is extended in the vertical direction in the space between the electrodes (see FIG. 3C). The extended discharge path merges with adjacent discharge paths to fill a discharge space to form a uniform front discharge (see FIG. 3D).

This discharge process includes (i) forming an electric field in the discharge space by applying a voltage between the electrodes, (ii) accelerating charged particles according to the electric field, (i) progressing the Townsend discharge process, and (i) neutralizing from a region with a high density of charged particles. Progress of plasma formation of gas, (v) formation of an initial discharge path along the electric field direction, (i) acceleration of the charged particles inside the plasma toward the opposite polarity electrode, and (i) each cycle of charged voltage after the end of one cycle of the driving voltage signal. Accumulated on the wall potential, (i) wall voltage due to wall potential, (i) voltage is applied to the opposite electrode by the reversed pulse, (x) wall voltage It can be understood that the combined applied voltage consists of the steps of forming a high field. Continuous polarity of the applied voltage is followed by steady front discharge.

4 illustrates a planar structure of the surface light source structure described in Korean Patent No. 10-0798674 filed and registered by the applicant. The discharge space is sealed by a predetermined sealing member outside the structure, and the upper plate 10 is formed with linear main electrode patterns X and Y parallel to each other in the vertical direction. The lower plate 20 opposite thereto is patterned with an auxiliary electrode I having a rectangular shape as a whole. The auxiliary electrode (I) pattern is arranged to surround the discharge space, and in particular, a component (P) parallel to the two main electrode patterns (X, Y) and a component (C) perpendicular to and intersecting between the main electrode patterns. It has a phosphorus upper and a lower portion. By adding an auxiliary electrode having such a structure, it was observed by the present inventors that it is possible to maintain a uniform and stable discharge over the entire surface light source, and to significantly suppress the occurrence of discharge shrinkage phenomenon.

However, such a surface light source structure is manufactured under the assumption of a rectangular surface light source, and when the shape of the surface light source is changed to circular or elliptical, etc., uniform and stable discharge may be performed in the form of the main electrode and the auxiliary electrode as described above. There is a problem that is difficult to maintain.

The present invention is to solve the problems of the prior art, it is an object to provide a surface light source structure that can maintain a uniform and stable discharge even if the shape of the surface light source structure is formed in a circular or oval shape as needed. do.

Surface light source structure according to the present invention for achieving the above object, the upper plate made of a translucent material of a circular or oval; A round or oval lower plate spaced apart from the upper plate at a predetermined interval; A support member spaced between the upper and lower plates to form a discharge space filled with a predetermined discharge gas at a predetermined pressure; A phosphor applied to at least a portion of an inner wall surface of the upper plate and an inner wall surface of the lower plate surrounding the discharge space; A pair of main electrodes patterned at predetermined positions of the upper and lower plates so as to emit visible light by exciting the phosphor by a plasma formed by generating an electric field in the discharge space, each of which has a predetermined driving voltage applied thereto; And an auxiliary electrode patterned on the lower plate or the upper plate to have at least one of a component parallel to at least one of the pair of main electrodes and a component intersecting the pair of main electrodes when looking at the discharge space from the upper plate. Characterized in that.

Here, the pair of main electrodes are point-symmetrical with respect to the center, and each main electrode may be implemented to form a shape in which a predetermined number of linear components are connected.

Alternatively, the pair of main electrodes may be point-symmetrical with respect to the center, and each main electrode may be formed along a circular edge.

In addition, the main electrode may be formed of a linear component constituting a pair spaced apart by a predetermined interval in each distribution line after distributing a predetermined number of diameter lines.

In addition, the pair of main electrodes may be composed of a point component provided in the center and a circle component formed along the circumference.

Preferably, the auxiliary electrode includes a raw component formed along the circumference.

Here, the auxiliary electrode may further include at least one linear component passing through the center.

In addition, the auxiliary electrode may include a linear component passing through the center and a plurality of second linear components parallel to the linear component.

In addition, the auxiliary electrode may include a linear component passing through the center and at least one second linear component perpendicular to the linear component.

Here, a positive pulse, a negative pulse, or a bipolar pulse may be applied to the pair of main electrodes.

In addition, the auxiliary electrode may float, apply a positive or negative waveform synchronized to any one of the pair of main electrodes, or apply a synchronized waveform to all of the pair of main electrodes, and may be grounded. have.

In addition, the upper plate and the lower plate may include a shape in which the circular shape extends in both directions in left and right symmetry.

According to the present invention, even if the shape of the surface light source structure is formed in a circular or elliptical shape, it is possible to maintain a uniform and stable discharge.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is a schematic view for explaining an embodiment of the surface light source structure of the present invention, illustrating a circular surface light source structure. As shown, the surface light source structure of the present embodiment, the upper plate 110 made of a circular transparent material, the circular lower plate 120 spaced at a predetermined interval from the upper plate 110, and the upper plate 110 and the lower plate 120 And a support member 130 spaced apart from each other to form a discharge space filled with a predetermined discharge gas at a predetermined pressure. In this case, Xe may be used as an ultraviolet light source as a kind of gas for forming a mercury-free light source, and He, Ne, Ar, Kr, or the like may be used as a buffer gas. Here, although the shape of the lamp is shown in a circular shape, the shape of the lamp is not limited to that shown, and as shown in FIGS. 6A and 6B, an ellipse, but the circular shape may be embodied in a symmetrically extended form in both directions. .

As illustrated in FIG. 7, a pair of main electrodes are patterned on the upper plate 110 or the lower plate 120 to emit visible light by exciting the phosphor by a plasma formed by generating an electric field in the discharge space. Predetermined driving voltages are applied to the electrodes, respectively.

Here, as shown in FIG. 7A, the pair of main electrodes are point-symmetric with respect to the center, and each main electrode may be implemented to have a shape in which a predetermined number of linear components are connected. Alternatively, as shown in FIG. 7B, the pair of main electrodes are point-symmetrical with respect to the center, and each main electrode may be formed of a curved component along a circular edge. At this time, each of the main electrodes is not the same distance apart, but the part with the longest distance (uppercase S) and the closest distance (lowercase letter s) is generated, in this structure, the distance between the electrodes close to The discharge begins and forms a form in which the discharge is transferred to the whole.

In addition, as shown in FIG. 7C, the main electrodes may be formed of linear components that form a pair spaced apart from each other by a predetermined number after distributing the diameter lines in a predetermined number. The pair of main electrodes may be composed of a point component provided at the center and a circle component formed along the circumference. In such a structure, since the distance between the electrodes is the same, it is possible to start the discharge by using the auxiliary electrode to transition to the total discharge. The shape of the main electrode is not limited to that shown, of course, various modifications may be made.

The auxiliary electrode is formed on the lower plate 120 or the upper plate 110 to have a component parallel to at least one of the pair of main electrodes and / or a component intersecting the pair of main electrodes when looking at the discharge space from the upper plate 110. do. At this time, the auxiliary electrode is a surface facing the surface on which the main electrode is formed, for example, when the main electrode is installed on the upper plate 110, the auxiliary electrode is preferably formed on the lower plate 120. The auxiliary electrode plays an auxiliary role to obtain a uniform front discharge on the lower surface of the lower plate 120.

8 is a diagram illustrating a shape of an auxiliary electrode. The auxiliary electrode may include a raw component formed along a circumference, as shown in FIGS. 8A to 8C. In particular, the auxiliary electrode fills the interior of the original component as shown in FIG. 8, includes at least one linear component passing through the center as shown in FIG. 8C, or a plurality of concentric circles as shown in FIG. 8D. It may be implemented in the form. 8E and 8F, the auxiliary electrode includes a linear component passing through the center and a plurality of second linear components parallel to the linear component, or at least one perpendicular to the linear component and the linear component passing through the center as illustrated in FIG. 8E. It may be composed of the second linear component of. The shape of the auxiliary electrode may be adaptively modified according to the shape of the main electrode. For example, when a pair of main electrodes are point-symmetrical with respect to the center as shown in FIG. 7B and formed of curved components along a circular border, the auxiliary electrodes are respectively shown in FIGS. 9A to 9E. It may include a component parallel to the main electrode and at least one component connecting the parallel component. However, of course, the formation of the auxiliary electrode is not limited to that shown. By the shape of the auxiliary electrode as described above, the auxiliary electrode plays a role of causing a discharge at a low voltage to transition to a total discharge.

Further, in the surface light source structure of the present invention, magnesium oxide is prevented to prevent damage to the phosphor on the inner wall, the exposed glass substrate surface, the electrode surface, or the surface of the dielectric layer covering the electrode by the plasma formed in the discharge space therein. It is preferable to form a protective film made of a material such as (MgO), strontium oxide (SrO), calcium oxide (CaO) or strontium calcium oxide (SrCaO), magnesium strontium oxide (MgSrO), or the like. The protective film may be entirely coated on a surface adjacent to the discharge space of the upper plate 10 and / or the lower plate 120, or may be locally coated as necessary. By forming such a protective film, the life of the surface light source structure can be extended, and the emission of secondary electrons can be promoted to contribute to stabilization of the discharge.

In an exemplary embodiment of the present invention, in order to further increase luminance and efficiency, the phosphor layer may be partially coated according to the position without applying a phosphor having a uniform thickness on the entire surface of the upper plate 110 as in the prior art.

The circular surface light source structure configured as described above may apply a positive pulse as shown in FIG. 10A or a negative pulse as shown in FIG. 10B to a pair of main electrodes, A bipolar pulse as shown in FIG. 10C can be applied. In this case, the auxiliary electrode may be a floating seeker, apply a positive or negative waveform synchronized with the waveform applied to the X or Y of the main electrode as shown in FIG. 11A, or the X of the main electrode as shown in FIG. 11B. And a waveform synchronized simultaneously with the waveform applied to Y, or grounded as shown in FIG. 11C.

The surface light source structure and the driving method thereof according to the present invention can be modified and applied in various forms within the scope of the technical idea of the present invention and are not limited to the above preferred embodiment. In addition, the embodiments and drawings are merely for the purpose of describing the contents of the invention in detail, and are not intended to limit the scope of the technical idea of the invention, the present invention described above is common knowledge in the technical field to which the present invention belongs As those skilled in the art can have various substitutions, modifications, and changes without departing from the spirit and scope of the present invention, it is not limited to the embodiments and the accompanying drawings. And should be judged to include equality.

1 schematically shows a surface light source structure of the prior art.

2 is a schematic view for explaining a method of driving a surface light source structure of the prior art.

3 is a diagram showing a change with time of a discharge state in a surface light source.

4 illustrates a planar structure of a conventional surface light source structure.

5 is a view schematically showing a circular surface light source structure according to the present invention.

6 is a view showing an example of the shape of the main electrode in the circular surface light source structure of FIG.

FIG. 7 is a diagram illustrating an example of a shape of an auxiliary electrode in the circular surface light source structure of FIG. 5.

FIG. 8 is a diagram illustrating another example of a shape of an auxiliary electrode in the circular surface light source structure of FIG. 5.

9 is a diagram illustrating an example of waveforms applied to a main electrode of the circular surface light source structure of FIG. 5.

FIG. 10 is a diagram illustrating an example of waveforms applied to an auxiliary electrode of the circular surface light source structure of FIG. 5.

<Description of Symbols for Main Parts of Drawings>

10, 110: top plate 20, 120: bottom plate

30: partition 130: support member

Claims (18)

A top plate made of a circular or oval translucent material; A round or oval lower plate spaced apart from the upper plate at a predetermined interval; A support member spaced between the upper and lower plates to form a discharge space filled with a predetermined discharge gas at a predetermined pressure; A phosphor applied to at least a portion of an inner wall surface of the upper plate and an inner wall surface of the lower plate surrounding the discharge space; A pair of main electrodes patterned at predetermined positions of the upper and lower plates so as to emit visible light by exciting the phosphor by a plasma formed by generating an electric field in the discharge space, each of which has a predetermined driving voltage applied thereto; And An auxiliary electrode patterned on the lower plate or the upper plate to have at least one of a component parallel to at least one of the pair of main electrodes and a component intersecting the pair of main electrodes when looking at the discharge space from the upper plate; Surface light source structure, characterized in that. The method of claim 1, The pair of main electrodes are point-symmetrical with respect to the center, and each of the main electrodes has a shape in which a predetermined number of linear components are connected to each other. The method of claim 1, The pair of main electrodes are point-symmetrical with respect to the center, and each main electrode is formed along a circular edge. The method of claim 1, The main electrode is a surface light source structure, characterized in that formed after the distribution of a number of diameter lines, a linear component forming a pair spaced apart a predetermined interval inside each distribution line. The method of claim 1, The pair of main electrodes is a surface light source structure, characterized in that consisting of a point component provided in the center and the original component formed along the circumference. The method of claim 1, The auxiliary electrode has a surface light source structure, characterized in that it comprises a circular component formed along the circumference. The method of claim 6, The auxiliary electrode includes at least one linear component passing through the center of the surface light source structure. The method of claim 1, The auxiliary electrode includes a linear component passing through the center and a plurality of second linear components parallel to the linear component. The method of claim 1, The auxiliary electrode includes a linear component passing through the center and at least one second linear component orthogonal to the linear component. The method of claim 1, And applying positive pulses alternately to the pair of main electrodes. The method of claim 1, And applying negative pulses alternately to the pair of main electrodes. The method of claim 1, And applying a bipolar pulse to the pair of main electrodes. The method of claim 1, The surface light source structure, characterized in that for floating the auxiliary electrode. The method of claim 1, And applying a positive or negative waveform synchronized to any one of the pair of main electrodes to the auxiliary electrode. The method of claim 1, And applying a positive or negative waveform synchronized to the auxiliary electrode to the pair of main electrodes. The method of claim 1, Plane light source structure, characterized in that for grounding the auxiliary electrode. The method of claim 1, The discharge gas is a surface light source structure, characterized in that it comprises at least one of Xe, He, Ne, Ar, Kr. The method of claim 1, The upper plate and the lower plate is a surface light source structure, characterized in that it comprises a shape extending in both directions in a symmetrical circular shape.

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