Method for making a shadow mask for an opposed discharge plasma display panel

The present invention is to provide a method for making a shadow mask for an opposed discharge plasma display panel by etching one lateral surface of a metal slab to produce a plurality of parallel and equidistant barrier ribs along the vertical and horizontal directions on the lateral surface and a discharging cell by enclosing every four adjacent barrier ribs. A shadow hole is formed at the middle of each discharging cell and etched through the metal slab, and at least one groove interconnected to the shadow holes is produced on another lateral surface of the metal slab by utilizing a rolling process or a stamping process. The adjacent grooves are interconnected with each other, and a plurality of air guide channels is formed on another lateral side, such that a shadow mask can be made in a simple and fast manner, chemical pollutions caused by a traditional double-sided etching can be minimized, and the product yield rate and the manufacturing cost can be effectively improved and lowered.

FIELD OF THE INVENTION

The present invention relates to a method for making a shadow mask for an opposed discharge plasma display panel, and more particularly to a method for making a shadow mask for an opposed discharge plasma display panel by utilizing a machining process, instead of a traditional double-sided etching process, to form a plurality of air guide channels in a simple and fast way on one side of the shadow mask needed for manufacturing the opposed discharge plasma display panel.

BACKGROUND OF THE INVENTION

Referring toFIG. 1for the manufacturing technology of a traditional opposite discharge AC type (AC) plasma display panel (PDP)10, different functional layers are formed on two glass substrates11,12, and the peripheries of the two glass substrates are sealed o form a space between the two glass substrates, and a special gas mixed according to a specific proportion such as helium (He), neon (Ne), xenon (Xe) or argon (Ar), etc is filled in the discharging cell13within the space between the two glass substrates. In the structure of a plasma display panel as shown inFIG. 1, the substrate facing the viewer is a front substrate11, and the front substrate11at its inner side sequentially includes a plurality of parallel transparent electrodes111, auxiliary electrodes (or bus electrodes)112, dielectric layers113, and protective layers (such as manganese oxide, MgO)114, and the corresponding rear substrate12sequentially includes a plurality of parallel data electrodes121, dielectric layers124, protective layers125, barrier ribs122, and evenly coated phosphors123(which could be red, green, or blue phosphors), such that if a voltage is applied to the electrodes111,112,121at related positions, the dielectric layers113,124at the corresponding positions will discharge electricity in the corresponding discharging cells13formed between the adjacent barrier ribs122, enabling the phosphors123to emit the corresponding color lights.

In the AC discharge plasma display panel10as shown inFIGS. 1 and 2, the electrodes on the front substrate11generally go through spluttering and photolithography to form a plurality of mutually isolated and horizontally aligned transparent electrodes111on the inner surface of the front substrate11, and then go through deposition (or spluttering) and photolithography or printing process to form the bus electrode112on the transparent electrode111, such that the bus electrode112reduces the line impedance of the transparent electrode111. The transparent electrode111(including bus electrode112) and the data electrode121disposed at corresponding positions of the rear substrate12form two opposed electrodes, so that if a voltage is applied to these electrodes111,121, their dielectric layers113,124in the corresponding discharging cells13will carry out opposed discharges, and the mixed gas therein will discharge electricity to produce an ultraviolet (UV) light and activate the phosphors123coated on the discharging cell13to emit three visible lights: red, green, and blue and display images. The traditional AC discharge plasma display panel10of this sort is also known as “opposite discharge plasma display panel”.

In the foregoing opposite discharge plasma display panel10as shown inFIGS. 1 and 2, the data electrode121on the rear substrate12is disposed at the bottom of the dielectric layer124and parallel to the corresponding transparent electrode111(also called “scan electrode” or “sustain electrode”) disposed on the front substrate11and vertically coupled to the position of each discharging cell13. A shadow mask20is attached onto the protective layer125at the top of the dielectric layer124, and the space corresponding to each shadow hole21on the shadow mask.20forms each discharging cell13, and the metal conductor around each shadow hole21serves as a barrier rib122for each discharging cell13and is formed by enclosing the adjacent barrier ribs122in the corresponding discharging cell13. The phosphor123is coated evenly onto the wall of the grid barrier rib122, and the coating area of the phosphor123is increased to effectively improve the luminescence efficiency of the plasma display panel10. However, the rear substrate12of the foregoing opposite discharge plasma display panel10is attached to the barrier rib122that is formed by the grid metal conductors disposed around each shadow hole21of the shadow mask20, such that after the front substrate11is attached on another side of the shadow mask20, and the peripheries of the two glass substrates11,12are sealed, each discharging cell13will not discharge or fill air easily due to the grid design of the barrier rib122.

To improve the efficiency of discharging and filling air, the traditional shadow mask20adopts a double-sided etching method as shown inFIG. 3to etch the required barrier ribs122and shadow holes21on one side of the shadow mask20and a plurality of air channels23on the other side of the shadow mask20and at the positions corresponding to the shadow holes21as shown inFIG. 4. Each air channel23is interconnected to the discharging cell13through the shadow hole21for effectively solving the air discharging and filling problem of the discharging cell. However, this method still has the following shortcomings:(1) In the double-sided etching method, the process of etching the barrier ribs122and the air channels23on both sides of the shadow mask20is quite complicated, and the level of difficulty is relatively high, and thus incurring a higher manufacturing cost.(2) In the double-sided etching method for making the shadow mask20, it is not easy to control the width and depth of the air channel23in the etching process as shown inFIG. 5. To ensure that the etched air channel23will not affect the size of the shadow hole21, the etching depth of the discharging cell13is generally reduced to increase the remaining thickness tm of the shadow mask20for etching and producing the air channel23. However, if the etching depth of the discharging cell13in this method is decreased, the coating area of the phosphor will become less, and thus causing an adverse effect to the luminescence efficiency of the opposite discharge plasma display panel.

SUMMARY OF THE INVENTION

In view of the shortcomings of the prior art double-sided etching method, such as a high production cost and a poor luminescence efficiency due to the barrier ribs and air channels being etched on both sides of the shadow mask of the opposite discharge plasma display panel, the inventor of the present invention based on years of experience to conduct extensive researches, and finally invented a method of making a shadow mask for an opposite discharge plasma display panel.

Therefore, it is a primary objective of the present invention is to etch a plurality of parallel and equidistant barrier ribs along the vertical and horizontal directions and on a side of a metal slab by an etching process, and form a discharging cell by enclosing every four adjacent barrier ribs. A shadow hole is disposed at the middle of each discharging cell and etched through the metal slab, and at least one groove interconnected to the shadow hole is produced on another side of the metal slab and at a position corresponding to each discharging cell by a machining process. The adjacent grooves are interconnected with each other, and a plurality of air guide channels is formed on another side, such that a shadow mask required for the opposite discharge plasma display panel can be made in a simple and fast manner. In addition to minimizing chemical pollutions caused by the traditional double-sided etching, the present invention also can effectively improve the product yield rate and lower the manufacturing cost.

Another objective of the present invention is to adopt a single-sided etching process to produce the required barrier ribs, discharging cells, and shadow holes on a lateral surface of the shadow mask, and the other lateral surface of the shadow mask is rolled or stamped along the horizontal direction, vertical direction, aslant direction, or two-dimensional interlacing direction by a rolling process or a stamping process at the position corresponding to each discharging cell to produce a groove interconnected to the shadow hole, such that the adjacent grooves are interconnected with each other to form a plurality of air guide channels for greatly enhancing the air discharging and filling efficiency of the discharging cell and accurately control the width and depth of the air channel, so as to increase the etching depth of the discharging cell and the coating area of the phosphor and effectively enhance the luminescence efficiency of the opposite discharge plasma display panel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a method of making a shadow mask for an opposite discharge plasma display panel. The shadow mask is a thin metal slab40as shown inFIG. 6before the shadow mask is manufactured, and both lateral surfaces of the metal slab40are flat and even. The method of the present invention adopts an etching process to etch a plurality of parallel and equidistant barrier ribs422along the vertical direction and horizontal direction on a lateral surface of the metal slab40, wherein a space is formed by enclosing every four adjacent barrier ribs422to produce a discharging cell43of the opposite discharge plasma display panel, and a shadow hole41is etched at the middle of each discharging cell43and penetrated through the metal slab40. A groove44is produced on another lateral surface of the metal slab40and at a position corresponding to the shadow hole41of each discharging cell43by a machining process instead of a traditional etching process, and the adjacent grooves44are interconnected with each other to form a plurality of air guide channels on the other lateral surface. InFIG. 7, the method of the invention also can select another lateral surface of the metal slab50for producing a plurality of grooves54disposed at the positions corresponding to the discharging cells43by a machining process, and the adjacent grooves54are interconnected to each other to form a plurality of air guide channels on the other lateral surface. A plurality of parallel and equidistant barrier ribs522is etched along the vertical direction and horizontal direction on a lateral surface of the metal slab50, wherein a space is formed by enclosing every four adjacent barrier ribs522to produce a discharging cell53of the opposite discharge plasma display panel, and the middle of each discharging cell53is penetrated through the metal slab50and interconnected with the groove54.

Referring toFIG. 8for the method according to a preferred embodiment of the present invention, a roller65is used to roll another lateral surface of the shadow mask and carry out a machining process, and the roller65includes a plurality of parallel and equidistant circular protruding ribs66disposed along the direction of its central axis. The roller65rolls along the vertical direction (which is the y-axis direction) on a thin metal slab60to produce a plurality of grooves along the vertical direction on the metal slab60and a plurality of air guide channels63on another lateral surface. As described above, the air guide channels63must be designed at a position corresponding to each discharging cell43of the shadow mask and interconnected with each corresponding shadow hole41.

Referring toFIG. 9for the method according to another preferred embodiment of the present invention, the method uses a roller75to roll another lateral surface of the shadow mask, and the roller75includes a plurality of linear protruding ribs77parallel to its central axis, and the linear protruding ribs77are parallel and equidistant with each other. The roller75rolls along the vertical direction (which is the y-axis direction) on a thin metal slab70to produce a plurality of grooves disposed along the horizontal direction (which is the x-axis direction) of the metal slab70and a plurality of air guide channels73on another lateral surface. The air guide channel73must be designed at a position corresponding to each discharging cell43of the shadow mask and interconnected to the shadow hole41.

Referring toFIG. 10for the method according to another further preferred embodiment of the present invention, the method uses a roller85to roll another lateral surface of the shadow mask, and the roller85includes a plurality of parallel and equidistant circular protruding ribs86disposed along its central axis and a plurality of linear protruding rib87parallel to its central axis, and the linear protruding ribs87are parallel and equidistant with each other, such that the roller85rolls along the vertical direction (which is the y-axis direction) on a thin metal slab80to produce a plurality of grooves along the vertical direction (which is the y-axis direction) and the horizontal direction (which is the x-axis direction) on the metal slab80and a plurality of air guide channels83,84along the vertical direction and the horizontal direction on another lateral surface. The air guide channel83,84must be designed at a position corresponding to each discharging cell43of the shadow mask and interconnected with the shadow hole41.

It is worth pointing out that the foregoing embodiments are some of the preferred embodiments of the present invention, but the actual practice of the invention is not limited to these preferred embodiments only. The people skilled in the art can base on the principle of the invention to produce the required barrier ribs, discharging cells, and shadow holes on a lateral side of the shadow mask by using a single-sided etching process, and adopts a machining process such as a rolling process (by using a roller) or a stamping process (by using a mold) to produce a groove interconnected to the shadow hole and disposed along a horizontal direction, vertical direction, aslant direction, and two-dimensional interlacing direction on another lateral surface of the shadow mask and at a position corresponding to each discharging cell, such that the adjacent grooves are interconnected with each other to produce a plurality of air guide channels. Such arrangement is intended to be covered by the scope of the claims of the present invention.

In summation of the description above, the manufacturing process of the present invention can produce a shadow mask for the opposite discharge plasma display panel in a simple and fast manner and use the machining process to accurately control the width and depth of the air channel. The invention not only reduces the chemical pollution problem caused by the traditional double-sided etching and greatly improves the efficiency of discharging and filling the air for the discharging cell and lowers the production cost of the shadow mask, but also increases the etching depth of the discharging cell and the coating area of the phosphor, so as to effectively enhance the luminescence efficiency and yield rate of the opposite discharge plasma display panel.