KR100447131B1 - Segmant Space, Field Emission Display Using The Same, And Fabricating Method Thereof - Google Patents

Abstract

The present invention relates to a segmented spacer having curved edges, a field emission display device using the same, and a method of manufacturing the same.

The segmented spacer according to the present invention is characterized by being formed by curved corners of the spacer sliced in the longitudinal direction and the width direction.

Description

Segmented Spacer, Field Emission Display Device Using The Same And Manufacturing Method Thereof {Segmant Space, Field Emission Display Using The Same, And Fabricating Method Thereof}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer, and more particularly, to a segmented spacer having curved edges, a field emission display device using the same, and a manufacturing method thereof.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes (CRTs). Such flat panel displays include liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), and electroluminescence (Electro-) displays. luminescence (EL). In order to improve the display quality, research and development are being actively conducted to increase the brightness, contrast and color purity of flat panel displays.

The FED concentrates a high field on a sharp cathode (emitter), emits electrons by a quantum mechanical tunnel effect, and displays an image by exciting the phosphor using the emitted electrons.

1 and 2, a conventional FED includes an upper plate UP having an anode electrode 4 and a phosphor 6 formed on an upper substrate 2, and a field emission array 20 on the lower substrate 8. ) Is provided with a lower plate DP.

The field emission array 20 of the lower plate DP includes a cathode electrode 10 and a resistive layer 12 formed on the lower substrate 8, an emitter 22 and a gate formed on the resistive layer 12. An insulating layer 14, a gate electrode 16 formed on the gate insulating layer 14, and a focusing insulating layer (not shown) formed on the gate electrode 16. The cathode electrode 10 supplies a current to the emitter 22, and the resistive layer 12 limits the overcurrent applied from the cathode electrode 10 toward the emitter 22 to uniform the emitter 22. It serves to supply current. The gate insulating layer 14 insulates between the cathode electrode 10 and the gate electrode 16. The gate electrode 16 is used as an extraction electrode for extracting electrons. A spacer 18 is installed between the upper substrate 2 and the lower substrate 8 to withstand external atmospheric pressure.

In order to display an image, a negative (-) cathode voltage is applied to the cathode electrode 10 and a positive (+) anode voltage is applied to the anode electrode 4. A gate voltage of positive polarity (+) is applied to the gate electrode 16. The electron beam 24 emitted from the emitter 22 is then accelerated toward the anode electrode 4. The electron beam 24 collides with the phosphor 6 of red, green, and blue (R, G, B) to excite the phosphor 6.

When the above-described FED is a low voltage type which is driven by applying a voltage of 400 to 1000 V to the anode electrode 4, the gap between the upper plate UP and the lower plate DP is set to about 200 to 500 μm, so the design and manufacture of the spacer 18 are possible. And the problem of material selection is relatively easy. However, in the low voltage FED, the luminous efficiency of the low voltage phosphors developed to date is not good and the electron focusing is not active. The high voltage FED developed in response to this has the advantage of being able to use a conventional cathode ray tube phosphor that operates at high voltage. On the other hand, in the high voltage FED, a high voltage of 1 to 10 kV must be applied to the anode electrode 4 to focus the electron beam, so that the distance between the upper plate UP and the lower plate DP should be maintained at least 1 mm. In this case, the spacer 18 has an aspect ratio of 1:20 in order to support the upper plate UP and the lower plate DP without bending or breaking. Accordingly, there is a difficulty in attaching the spacer 18 precisely aligned between the pixels.

As a spacer having a conventional high aspect ratio, processing using a rib-shaped spacer 18a, a cross-shaped spacer 18b, a cylindrical spacer 18c, and photosensitive glass (PSG) as shown in FIGS. 3A to 3E There are various forms such as the type spacers 18d and 18e.

Among these, the rib-shaped spacer 18a has an advantage of stably maintaining a gap between the upper plate UP and the lower plate DP, but has a problem that is difficult to apply to a large panel. That is, it is difficult to apply a spacer having a length of several tens of centimeters to a structure having a high aspect ratio of 1 to 3 mm in a width of several tens of micrometers. In detail, the rib-shaped spacer 18a having a length of several tens of centimeters to be applied to a large panel may not be aligned correctly due to shaking in the process of combining the upper plate UP and the lower plate DP. . Furthermore, the higher the height of the rib spacer 18a, the more the bending occurs even if it is slightly inclined away from the vertical. This problem also occurs in the case of the spacers 18d and 18e shown in FIGS. 3d and 3e using photosensitive glass.

Since the cross spacer 18b shown in FIG. 3B can be positioned only in a portion that needs to support the vacuum stress as shown in FIG. 4, the spacer form is large when the large panel is applied like the rib spacer 18a. The problem of lengthening and the problem of vacuum exhaust can be solved.

However, the cross spacer 18b has the following problems.

First, each discharge cell is formed with a predetermined interval therebetween as shown in FIG. 4, and the cross-shaped spacer 18b is relatively smaller because the vertical gap b is narrower than the horizontal gap a. There is a problem that is difficult to align the wing of the correct position. In detail, as illustrated in FIG. 5A, the lengths of the first and second blades 26a and 26b of the cross spacer 18b are about 1 mm, and the width of each blade 26a and 26b is about 50 μm. In one case, the inclination θ of at least one of the first and second vanes 26a, 26b allows a deviation of about 2 ° or less. However, with current production techniques, it is difficult to have a deviation of 2 ° or less. If the first wing 26a is inclined to have a deviation of 2 ° or more, as shown in FIG. 5B, a space of 25 μm is required on one side and a length of 50 μm on both sides. Therefore, the space (c) of the black matrix on which the cross spacer 18b is to be placed is the minimum with a width of 50 μm + an extra space of 50 μm + an alignment tolerance of 20 μm (± 10 μm) of the cross spacer 18b. Securing at least 120 μm can prevent the cross spacer 18b from invading the phosphor. Accordingly, there is a problem in that the width of the black matrix increases and the luminance decreases.

The second problem is the number and price of spacers required for a panel. The cross spacer 18b needs about 4000 pieces based on 20 inches, and the cylindrical spacer 18c needs about 7000 to 8000 pieces based on 20 inches. Inserting such a large number of spacers into the panel is also difficult to process and there is a problem that the manufacturing cost increases.

The third problem is the processing of the edge portion of the cross spacer 18b. If the edge portion is not smoothed, fine cracks are generated. This crack creates fine glass particles, which causes product defects.

Accordingly, an object of the present invention is to provide a segmented spacer having curved edges, a field emission display device using the same, and a method of manufacturing the same.

1 is a perspective view showing a conventional field emission display device.

FIG. 2 is a cross-sectional view of the field emission display device illustrated in FIG. 1. FIG.

3A to 3E are views showing various forms of the spacers shown in FIGS. 1 and 2.

4 shows a cross spacer mounted between an upper plate and a lower plate;

5A and 5B are diagrams illustrating a phenomenon in which the alignment of the cross spacers shown in FIG. 4 does not match.

6 is a perspective view showing a field emission display device according to the present invention;

FIG. 7 is a cross-sectional view illustrating the field emission display device illustrated in FIG. 1. FIG.

8A to 8D are views illustrating a method of manufacturing the segmented spacer shown in FIG. 7.

9A and 9B show the segmented spacer shown in FIG.

FIG. 10 is a view illustrating a phenomenon in which atmospheric pressure is applied after the segmented spacer shown in FIG. 7 is mounted in a panel to perform vacuum exhaust.

11a and 11b show the stress distribution of the spacer according to the prior art and the invention.

<Description of Symbols for Main Parts of Drawings>

2,32: upper substrate 4,34: anode electrode

6,36: phosphor 8,38: lower substrate

10,40 cathode electrode 12,42 resistive layer

14,44 gate insulating layer 16,46 gate electrode

18,48: spacer 20,50: field emission array

22,52: emitter

In order to achieve the above object, the segmented spacer according to the present invention is characterized in that it is formed by curved each corner of the spacer sliced in the longitudinal direction and the width direction.

The length of the segmented spacer in the longitudinal direction is characterized in that about 1 ~ 2cm.

The remaining area excluding the curved area of the segmented spacer occupies about 70 to 80% of the entire area.

In order to achieve the above object, the field emission display device according to the present invention is formed between the upper plate and the lower plate and the upper plate and the lower plate formed to face each other, and formed by curved each corner after the slice in the longitudinal direction and the width direction And segmented spacers.

The lower plate includes a cathode electrode formed on the lower substrate, an emitter formed on the cathode electrode to emit electrons, a gate electrode controlling an electron emission amount of the emitter portion, and an insulating film for insulating the gate electrode and the emitter. It is characterized by.

The upper plate includes an upper substrate disposed to face the lower substrate, an anode electrode for accelerating the electron beam emitted from the emitter, and a phosphor for emitting visible light by the collision of the electron beam.

The length of the segmented spacer in the longitudinal direction is characterized in that about 1 ~ 2cm.

The remaining area excluding the curved area of the segmented spacer occupies about 70 to 80% of the entire area.

The segmental spacer is characterized in that about several hundred are formed between the upper plate and the lower plate.

In order to achieve the above object, the manufacturing method of the field emission display device according to the present invention comprises the steps of slicing the material of the spacer in the width direction and the longitudinal direction, and each corner of the material of the sliced spacer is curved to form a segmented spacer And forming a segmented spacer between the upper plate and the lower plate.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 6 to 11B.

6 and 7 are a perspective view and a cross-sectional view showing an FED according to the present invention.

6 and 7, the FED according to the present invention is a segment type formed between the upper plate UP and the lower plate DP formed to face the upper plate UP, and the upper plate UP and the lower plate DP. Spacer 48 is provided.

The upper plate UP includes an upper substrate 32, an anode electrode 34, and a phosphor 36 formed thereon.

The lower plate DP includes a lower substrate 38 and a field emission array 50 formed thereon. The field emission array 50 includes the cathode electrode 40 and the resistive layer 42 formed on the lower substrate 38, the emitter 52 and the gate insulating layer 44 formed on the resistive layer 42. And a gate electrode 46 formed on the gate insulating layer 44 and a focusing insulating layer (not shown) formed on the gate electrode 46.

The cathode electrode 40 supplies current to the emitter 52, and the resistive layer 42 restricts the overcurrent applied from the cathode electrode 40 toward the emitter 52, thus making it uniform to the emitter 52. It serves to supply current. The gate insulating layer 44 insulates between the cathode electrode 40 and the gate electrode 46. The gate electrode 46 is used as an extraction electrode for drawing electrons.

The cathode voltage of negative polarity (-) is applied to the cathode electrode 40 of the FED and the anode voltage of positive polarity (+) is applied to the anode electrode 34. The gate voltage of positive polarity (+) is applied to the gate electrode 46. The electron beam is emitted into the vacuum by the high electric field formed by the applied voltage. The electron beam 54 emitted from the emitter 52 is then accelerated toward the anode electrode 34. The electron beam 54 collides with the phosphor 36 of red, green, and blue (R, G, B) to cause the phosphor 36 to emit light.

The segmented spacer 48 serves to support the upper plate UP and the lower plate DP by overcoming the pressure difference between the vacuum space of the upper plate UP and the lower plate DP and the atmospheric pressure. Segmented spacers 48 are formed by filleting or chamfering each corner.

A method of manufacturing the segmented spacer 48 will be described with reference to FIGS. 8A to 8D.

Referring to FIG. 8A, a material 48a of segmented spacers is prepared. As the segmented spacer material 48a, the same material as that of the upper and lower substrates 32 and 38 is used. It is preferably formed of a glass-based material. The height H of the segmented spacer material 48a is equal to the gap between the upper plate UP and the lower plate DP, ie, the cell gap. That is, if the distance between the upper plate UP and the lower plate DP is 2 mm, the height of the segmented spacer material 48a is formed to be 2 mm.

Referring to FIG. 8B, the material 48a of the segmented spacer is sliced in the longitudinal direction. Each width W sliced in the longitudinal direction becomes the width of a later segmented spacer. The thicker the width W, the smaller the number of spacers. The smaller the width W, the larger the number of spacers.

Referring to FIG. 8C, the material 48a of the segmented spacer sliced in the longitudinal direction is cut in the width direction. Each length (L) sliced in the width direction is cut to about 1 ~ 2cm. In the case of a rib-shaped spacer having a length of several tens of centimeters, when applied to a 20-inch panel, it is formed to have a relatively smaller length in order to prevent it from being accurately aligned due to warpage.

Referring to FIG. 8D, the material 48a of the segmented spacer sliced in the width direction and the longitudinal direction is filleted or chamfered to fillet the width direction and the length direction as shown in FIGS. 9A and 9B. Formed segmented spacers 48.

The segmented spacer 48 is formed by applying a predetermined pressure to the material 48a of the segmented spacer sliced in the length and width directions by using a drawing process machine 60 having a rounded outlet 62. Done. Accordingly, the segmented spacers 48 are also formed in rounded corners.

The radius of this fillet may vary depending on the thickness and length of the segmented spacer 48. Preferably, the remaining area of the segmented spacer 48 except for the filleted area is formed to occupy about 70 to 80% of the entire area.

Fillet treatment of each corner of the segmented spacer 48 according to the present invention allows the spacer 48 to be mounted in the panel to perform vacuum evacuation, and then to the segmented spacer 48 even if atmospheric pressure is applied as shown in FIG. 10. The stress to be applied can be reduced. This will be described with reference to FIGS. 11A and 11B.

11A and 11B are diagrams showing stress distribution by performing a computer-assisted finite element analysis (FEM) when a load by atmospheric pressure is applied to a spacer according to the related art and the present invention.

When the spacer is formed between the upper plate UP and the lower plate DP and vacuum evacuation is performed, the upper plate UP and the lower plate DP are bonded together using the material 60 to compress the load in the axial direction by atmospheric pressure. Will receive. In this case, since a localized stress concentration is generated at the edge of the conventional spacer on the surface under load, a stress distribution having a maximum stress of 5.371 appears as shown in FIG. 11A. Accordingly, brittle materials such as glass or ceramic, which are materials of conventional spacers, are generally strong in compression stress and weak in tensile stress, and thus cracks in the spacer due to strong tensile stress on the surface. Will occur. Fine debris generated at this time may cause arcing, resulting in product defects.

On the other hand, according to the present invention, it can be seen that the segmented spacer 48 has a sharply decreased tensile stress on the surface as shown in FIG. 11B by a maximum of 0.573751 by removing the edge portion where stress concentration occurs through fillet treatment. have.

Accordingly, in the related art, spacers are relatively formed to withstand the tensile stress that generates cracks, thereby making the manufacturing process complicated and having a high defect rate as well as high production costs. On the other hand, in the present invention, it can withstand the tensile stress through the fillet treatment, so that the manufacturing process is simplified and the process is simple as well as the cost is reduced by forming relatively less.

As described above, the segmented spacer according to the present invention, the field emission display device using the same, and a method of manufacturing the same are subjected to the fillet treatment or the chamfering treatment of the edges of the segmented spacer. Accordingly, invasion of the phosphor due to warpage of the spacer can be prevented. In addition, it is possible to reduce the stress at the upper end portion can reduce the number of spacers from thousands of conventional to hundreds, which simplifies the process and can reduce the manufacturing cost. In addition, cracks can be prevented and the yield is high.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (10)

Segmented spacers, characterized in that formed by curved each corner of the spacer sliced in the longitudinal direction and the width direction. The method of claim 1, Segmented spacer, characterized in that the length in the longitudinal direction of the segmented spacer is about 1 ~ 2cm. The method of claim 1, Segmented spacers, characterized in that the remaining area excluding the curved region of the segmented spacer occupies about 70 ~ 80% of the total area. An upper plate and a lower plate formed to face each other, And a segmented spacer formed between the upper plate and the lower plate and sliced in the longitudinal direction and the width direction and curved at each corner thereof. The method of claim 4, wherein The bottom plate is A cathode electrode formed on the lower substrate, An emitter formed on the cathode to emit electrons; A gate electrode controlling an electron emission amount of the emitter part; And an insulating film for insulating the gate electrode and the emitter. The method of claim 4, wherein The top plate is An upper substrate disposed to face the lower substrate; An anode electrode for accelerating the electron beam emitted from the emitter; And a phosphor for emitting visible light by the collision of the electron beam. The method of claim 4, wherein And the length of the segmented spacer in the longitudinal direction is about 1 to 2 cm. The method of claim 4, wherein The remaining area of the segmented spacer, except for the curved area, occupies about 70 to 80% of the entire area. The method of claim 4, wherein And about hundreds of segmented spacers are formed between the upper plate and the lower plate. Slicing the material of the spacer in the width and length directions; Curving each corner of the material of the sliced spacer to form a segmented spacer; And mounting the segmented spacer between an upper plate and a lower plate.