JP2006114325A - Manufacturing method of display device and press-forming die used in the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a display device, capable of flattening the surface of a phosphor layer. <P>SOLUTION: After flattening phosphor layers R, G, B by pressurizing them by using a press-forming die 100 equipped with a plurality of projecting parts formed into projections, corresponding to the phosphor layers R, G, B, a metal back layer, is formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a flat display device in which a front substrate having a phosphor layer and a metal back and a rear substrate having a large number of electron-emitting devices are arranged to face each other, and a press die used in this method.

  2. Description of the Related Art In recent years, various flat-type image display devices have attracted attention as next-generation lightweight and thin display devices that replace cathode ray tubes (hereinafter referred to as CRTs). For example, as a type of field emission display (hereinafter referred to as FED) used as a flat display device, development of a display device (hereinafter referred to as SED) including a surface conduction electron-emitting device as an electron source is being promoted. ing.

  The SED includes a front substrate and a rear substrate that are arranged to face each other at a predetermined interval, and these substrates constitute a vacuum envelope by joining peripheral portions to each other through a rectangular frame-shaped side wall. Yes. A phosphor screen including a phosphor layer of three colors and a light shielding layer is formed on the inner surface of the front substrate, and on the inner surface of the rear substrate, as an electron source for exciting and emitting the phosphor, a large number corresponding to each pixel is formed. The electron-emitting devices are arranged. Each electron-emitting device includes an electron-emitting portion and a pair of electrodes that apply a voltage to the electron-emitting portion. Further, on the phosphor screen, a metal back is formed for acting as an anode electrode and for reflecting light from the phosphor layer excited and emitted to the front substrate side.

  As a method of forming the metal back, for example, a method of forming a metal back on the phosphor screen after flattening the surface of the phosphor screen as a base in advance is known.

Usually, when leveling a layer printed on the surface of the substrate, a method is adopted in which the surface on which the printed layer is formed is faced up and the substrate is left in the air for a certain period of time to flatten the surface of the printed layer. For example, a technique is disclosed in which hot air is applied to lower the viscosity of the alignment film and eliminate unevenness on the surface of the printed alignment film (see Patent Document 1).
JP2003-57625A.

  However, it takes time for a printed layer made of a viscous material to become flat. For example, a flat substrate is left in the atmosphere for a certain period of time, and a phosphor screen composed of a phosphor layer and a black matrix layer formed on the flat substrate is used. It takes 30 minutes to 60 minutes for the surface to become flat. As a result, there is a problem that the manufacturing time becomes long.

  In addition, when a metal back is formed on a non-flat phosphor layer, a non-flat metal back is formed, and light from the phosphor layer is not sufficiently reflected, which causes a problem that the luminance of the display device is lowered.

  The present invention has been made in view of the above points, and an object thereof is to provide a method for manufacturing a display device capable of flattening the surface of a phosphor layer and a press die used in this method.

  To achieve the above object, the present invention provides a method of manufacturing a display device including a flat substrate on which a phosphor screen including a plurality of phosphor layers and a light shielding layer is formed, and pressurizes only the phosphor layer, The surface of the phosphor layer of the phosphor screen is flattened.

  In order to achieve the above object, the press die of the present invention is used in a method for manufacturing a display device including a flat substrate on which a phosphor screen including a plurality of phosphor layers and a light shielding layer is formed, and the phosphor A convex portion disposed opposite to the screen and opposed to the phosphor layer; and a concave portion opposed to the light shielding layer, wherein pressure is applied toward the phosphor screen so that the convex portion is the phosphor. It is characterized by flattening the layer.

  According to the present invention, the surface of the phosphor layer can be flattened in a short time, the metal back formed thereon can be flattened, and the luminance of the display device can be increased.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, an SED will be described as an example of a display device according to an embodiment of the present invention.

  FIG. 1 is a schematic perspective view of a display panel of an SED. As shown in FIG. 1, a display panel 1 of an SED includes a front substrate 10 and a rear substrate 12 each made of a rectangular glass plate, and these substrates are arranged to face each other with a certain gap. The distance between the substrates is set to about 1.0 to 2.0 mm. The front substrate 10 and the rear substrate 12 are joined to each other through a rectangular frame-shaped side wall 14 made of glass, and constitute a flat vacuum envelope having a vacuum inside.

  As shown in FIG. 2, a phosphor screen 16 that functions as an image display surface is formed on the inner surface of the front substrate 10. The phosphor screen 16 is configured by arranging red, green, and blue phosphor layers R, G, and B, and a light shielding layer 11, and these phosphor layers R, G, and B are formed in a stripe shape or a dot shape. ing. A metal back 17 made of aluminum or the like is formed on the phosphor screen 16.

  On the inner surface of the rear substrate 12, a number of surface-conduction electron-emitting elements 19 that emit electron beams are provided as electron sources for exciting and emitting the phosphor layers R, G, and B of the phosphor screen 16. ing. These electron-emitting devices 19 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel. Each electron-emitting device 19 includes an electron emitting portion (not shown) and a pair of device electrodes for applying a voltage to the electron emitting portion. In addition, on the inner surface of the back substrate 12, a large number of wirings 21 for supplying a voltage to the electron-emitting devices 19 are provided in a matrix shape, and end portions thereof are drawn out of the display panel 1.

  The side wall 14 functioning as a bonding member is sealed to the peripheral edge of the front substrate 10 and the peripheral edge of the rear substrate 12 by, for example, a sealing material 20 such as low melting glass or low melting metal, and these substrates are bonded to each other. is doing.

  Further, the display panel 1 includes a rectangular plate-like spacer 22 disposed between the front substrate 10 and the rear substrate 12. The spacers 22 are arranged in a stripe shape, abut against the inner surfaces of the front substrate 10 and the rear substrate 12 so as not to interfere with the respective electron-emitting devices 19 and the phosphor layers R, G, and B, and act on these substrates. The atmospheric pressure load is supported, and the distance between the substrates is maintained at a predetermined value. In addition, the shape of the spacer is not limited to this, and may be, for example, a large number of columnar spacers.

  When displaying an image, the electron-emitting device 19 is driven through the wiring 21 to emit an electron beam from the selected electron-emitting device, and an anode voltage is applied to the phosphor layer 16 and the metal back 17. The electron beam emitted from the electron emitter 19 is accelerated by the anode voltage and collides with the phosphor layer 16. As a result, the phosphor layers R, G, and B of the phosphor screen 16 are excited to emit light and display an image.

  Next, a method for manufacturing this SED will be described.

  First, with reference to FIG. 3 (a), (b), the press die used in the manufacturing process of SED based on this invention is demonstrated. Fig.3 (a) shows the schematic perspective view of a press type | mold, FIG.3 (b) shows the EE arrow sectional drawing of Fig.3 (a).

  As shown in FIGS. 3A and 3B, the press die 100 has a first surface 100A and a second surface 100B. The press die 100 is formed with a plurality of convex portions 101 protruding toward the first surface 100A side. The plurality of convex portions 101 are formed at positions corresponding to the phosphor layers R, G, and B, and the uppermost protruding upper surface 101A is flat. The press die 100 is made of rubber, metal, or the like, and is etched using a mask corresponding to the phosphor layers R, G, and B so that the surface is uneven. The surface of the upper surface 101A of the protrusion 101 is flat. In order to be polished.

  First, a mesh-like light shielding layer 11 is formed on the front substrate 10 using a predetermined pattern corresponding to a dot shape. Between the light shielding layers 11, dot-like phosphor layers R, G, and B are formed by using a photolithography technique. As a result, the surfaces of the phosphor layers R, G, and B constituted by the phosphor particles corresponding to the respective colors are not flat as shown in FIG. 4, and a large surface roughness (unevenness) remains. Therefore, the surfaces of the fluorescent layers R, G, and B are flattened as described below using the press die 100 described in FIG.

  As shown in FIG. 5, the press die 100 is positioned so that the convex portion 101 of the press die 100 and the phosphor layers R, G, and B on the front substrate 10 face each other, and is arranged to face the front substrate 10. The More specifically, the press die 100 is disposed so that the first surface 100A and the front substrate 10 face each other, and the flat upper surface 101A of the convex portion 101 is positioned so as to face the phosphor layers R, G, B. ing.

Thereafter, as shown in FIG. 6, pressure is applied to the phosphor layers R, G, and B from the press die 100 side using a roller 102. In the present embodiment, the surfaces of the phosphor layers R, G, and B can be flattened by a pressure of 10 to 10000 N / cm ² , more preferably 500 to 5000 N / cm ² . After pressurizing the phosphor layers R, G, and B through the press mold 100, the press mold 100 is peeled off to form phosphor layers R, G, and B having a flat surface as shown in FIG. The

  A thin coating film made of an organic resin such as nitrocellulose is formed on the phosphor screen 16 including the phosphor layers R, G, and B having a flat surface by, for example, a spin method. The resulting Al is vacuum deposited and baked to remove organic matter. Therefore, the metal back 17 having a flat surface is formed.

  Thereafter, the electron-emitting device 19 and the wiring 21 prepared in advance are provided, and the back substrate 12 in which the side wall 14 and the spacer 22 are joined, and the phosphor screen 16 and the metal back 17 are formed as described above. The front substrate 10 is placed in a vacuum chamber, the inside of the vacuum chamber is evacuated, and then the first substrate is bonded to the second substrate via the side wall 14. Thereby, the phosphor layers R, G, and B are flattened by the press die 100, and the SED including the flat metal back 17 formed thereon is manufactured.

  As described above, the phosphor screen 16 of the front substrate 10 is pressed by the press mold 100 including the plurality of convex portions 101 whose portions corresponding to the phosphor layers R, G, and B are convex, so that the phosphor layers R, The upper surfaces of G and B are smoothed. As a result, the surface roughness of the phosphor layers R, G, B is reduced in a short time without damaging the phosphor layers R, G, B, and the surfaces of the phosphor layers R, G, B are flattened. Can be. Further, the surface of the metal back 17 formed on the upper surfaces of the phosphor layers R, G, and B is also flattened, the film formability of the metal back 17 is improved, and a good metal back can be obtained. Further, in the display device including the front substrate 10 on which the metal back 17 having a flat surface is formed, the withstand voltage characteristic is improved, and display with high luminance and little luminance deterioration can be realized.

  Further, the phosphor layers R, G, and B constituted by the phosphor particles are pressed by the press die 100, whereby the density of the phosphor particles is increased, and the denseness of the phosphor layers R, G, and B is increased. Will improve. For this reason, when incorporated in a display device, a display with high luminance and little luminance deterioration can be realized. In particular, in a display device driven at a low voltage, it is possible to obtain a display device with high quality without luminance unevenness.

  Note that the phosphor layers R, G, and B formed on the front substrate 10 are extremely thin with a thickness of about 10 μm. Therefore, the convex portion 101 of the press die 100 described above is slightly convex than the other portions. Just being there is effective. Incidentally, when the surface of the light-shielding layer 11 is slightly higher than the phosphor layers R, G, B, in a flat press mold different from the present invention, before contacting the surfaces of the phosphor layers R, G, B. Since the phosphor layers R, G and B are in contact with the light shielding layer 11 and are not sufficiently pressurized, there is a possibility that the phosphor layers are not sufficiently flattened. Further, there is a possibility that the light shielding layer 11 pressed by the flat press mold enters the phosphor layers R, G, and B, and the two are mixed. Further, even when the phosphor layers R, G, B and the light shielding layer 11 are formed to have substantially the same height, if the layers are pressed by a flat press mold, the phosphor layers R, G, B And the light shielding layer 11 may be mixed.

  The press die 100 according to the present invention not only reliably pressurizes and flattens the phosphor layers R, G, B by the convex portions 101 corresponding to the phosphor layers R, G, B, but also slightly increases the film pressure. Even when the phosphor layers R, G, and B that have been formed are pressed, the convex portion 101 serves as a refuge for the light shielding layer 11 extruded by the pressed phosphor layers R, G, and B. Other recesses are secured. For this reason, the possibility that the light shielding layer 11 and the phosphor layers R, G, and B are mixed can be avoided. This is particularly effective when the light shielding layer 11 is higher than the phosphors R, G, and B.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  For example, as described above, the present invention is particularly effective when the light shielding layer 11 is formed higher than the phosphor layers R, G, B. However, the present invention is not limited to this, and the light shielding layer 11 and the phosphor layers R, Even if the phosphor layers R, G, and B are pressed on the surface of the phosphor screen 16 formed with the same heights of G and B using the press mold 100 shown in FIG. Layers R, G, B can be flat. With this configuration, not only the surfaces of the phosphor layers R, G, and B become flat, but also the height difference between the light shielding layer 11 and the phosphor layers R, G, and B can be reduced. A body screen 16 can be formed. Therefore, since the phosphor screen 16 which is the underlayer of the metal back 17 becomes flat, the deposited metal back 17 is more easily formed flat.

  In the present embodiment, it has been described that the phosphor layers R, G, and B are formed in a dot shape by using a photolithography technique. However, the present invention is not limited to this configuration, and is formed in a stripe shape by screen printing. Also good. Correspondingly, in the present embodiment, it has been described that the press die 100 includes the convex portions 101 formed in a dot shape as shown in FIG. 3, but the present invention is not limited to this configuration, and in the long side direction. It may be a long stripe-shaped protrusion or a stripe-shaped protrusion that is long in the short side direction.

  Furthermore, the press die 100 is not limited to the structure formed by etching and polishing as described above, and may be formed by press molding or injection molding, for example. In the present embodiment, it has been described that the metal back 17 is formed on the entire surface of the phosphor screen 16. However, the present invention is not limited to this configuration, and the metal back 17 includes at least the phosphor layers R, G, B. The metal back 17 on the light shielding layer 11 may be removed. In this way, as shown in FIG. 7, when the metal back 17 is formed on the phosphor layers R, G, and B whose upper surface is lower than that of the light shielding layer 11, the surface becomes flat, and thereafter For example, it becomes easy to form a conductive portion that connects each metal back 17 formed on the phosphor layers R, G, and B to the common electrode. In addition, the metal back 17 has been described as being formed in a dot shape using a photolithography technique, but is not limited to this configuration, and a method using a transfer film may be used. That is, a transfer film in which a metal film such as Al and an adhesive layer are laminated in order on a base film such as a polyester resin is disposed so that the adhesive layer is in contact with the phosphor screen, and the base film is pressed after being pressed. Remove. Then, the adhesive layer is baked to decompose and remove organic substances. Thereby, the metal back 17 having a flatr surface can be formed.

  Further, in the present embodiment, it has been described that the press mold 100 pressurizes the phosphor layers R, G, and B using the roller 102. However, the present invention is not limited to this configuration, and a method of applying uniaxial pressure or hydrostatic pressure is used. And may be pressurized.

  Furthermore, in the present embodiment, the phosphor layers R, G, and B have been described as being flattened by being pressed by the press die 100. However, the present invention is not limited to this configuration, and a thermoplastic resin is applied to each color phosphor. The phosphor layers R, G, and B made of the mixed liquid mixture may be formed, and the press mold 100 may be pressurized at the same time. With this configuration, the phosphor layers R, G, and B containing the heated thermoplastic resin have a reduced viscosity, and are flattened by receiving pressure from the press die 100. As a result, the phosphor layers R, G, and B are made flat in a shorter time without being damaged. Further, the surface of the metal back 17 formed on the upper surfaces of the flatter phosphor layers R, G, and B is also flattened like a mirror surface, so that the film formability of the metal back 17 is improved and good. A metal back can be obtained. Further, in the display device including the front substrate 10 on which the metal back 17 having a mirror surface is formed, the withstand voltage characteristic is improved, and display with higher luminance and less luminance deterioration can be realized.

At this time, it is preferable to use a thermoplastic resin having a softening temperature of 50 to 350 ° C. The pressure and heat applied to the phosphor layers R, G, and B through the press die 100 are applied from the viewpoint of the fluidity and mobility of the phosphor particles and the heat resistance of the front substrate 10 that is a glass substrate. Is 10 to 10000 N / cm ² , more preferably 500 to 5000 N / cm ² , and the heating temperature is 50 to 350 ° C., more preferably 100 to 250 ° C. When the heating temperature is lower than 50 ° C., the fluidization of the thermoplastic resin contained in the phosphor layer becomes insufficient, and the phosphor particles are strongly bound to the thermoplastic resin. Therefore, the phosphor particles are strongly bound to the thermoplastic resin. Therefore, in order to release and move the phosphor particles from being bound by the thermoplastic resin, a pressure exceeding 10,000 N / cm ² is required. However, there is a possibility that the phosphor particles are damaged by such an excessive pressure, and the luminance is greatly lowered. Further, heating exceeding 300 ° C. prevents the glass substrate from being deformed due to high temperature, so that sufficient pressurization cannot be performed, and the surface of the phosphor layer may be insufficiently smoothed.

Schematic which shows an example of the display panel which is one embodiment of this invention, 1 is a schematic cross-sectional view of the display panel shown in FIG. Schematic showing a press die according to the present invention, Sectional drawing which shows 1 process of the manufacturing method of the display apparatus which is one embodiment of this invention, Sectional drawing which shows the process following the process shown in FIG. Sectional drawing which shows the process following the process shown in FIG. Sectional drawing which shows the process following the process shown in FIG.

Explanation of symbols

1 ... Display panel,
10: Front substrate,
11 ... light shielding layer,
R, G, B ... phosphor layer,
15 ... Fixed layer,
16 ... phosphor screen 17 ... metal back,
19 ... an electron-emitting device,
100 ... press mold,
100A ... first surface,
100B ... second surface,
101 ... convex part,
101A ... the upper surface of the convex part,
102. Roller.

Claims (6)

In a method for manufacturing a display device including a flat substrate on which a phosphor screen including a plurality of phosphor layers and a light shielding layer is formed,
A method for manufacturing a display device, wherein only the phosphor layer is pressurized to flatten the surface of the phosphor layer of the phosphor screen.   2. The display device according to claim 1, wherein the upper surface of the phosphor layer is pressed by a press mold in which a portion corresponding to the phosphor layer is convex and a portion corresponding to the light shielding layer is concave. Production method. The phosphor layer includes a thermoplastic resin,
The method for manufacturing a display device according to claim 1, wherein the phosphor layer is pressurized while being heated. Used in a method of manufacturing a display device including a flat substrate on which a phosphor screen including a plurality of phosphor layers and a light shielding layer is formed,
The convex portion is disposed opposite to the phosphor screen and includes a convex portion facing the phosphor layer and a concave portion facing the light shielding layer, and pressure is applied toward the phosphor screen so that the convex portion is A press die for flattening the phosphor layer.   The press mold according to claim 4, wherein the convex portion is formed in a dot shape corresponding to the shape of the phosphor layer.   The press mold according to claim 4, wherein the convex portion is formed in a stripe shape corresponding to the shape of the phosphor layer.

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