Field emission display and method for manufacturing same

Abstract

An exemplary field emission display includes a first substrate (21) and a second substrate (22) being at opposite sides of the field emission display, a metal layer (210) disposed on an inner surface of the first substrate, a transparent electrode (221) disposed on an inner surface of the second substrate and spaced apart from the metal layer, a fluorescent layer (223) disposed on the transparent electrode, and a poly-silicon layer (212) disposed on the metal layer. The poly-silicon layer defines a plurality of tips (218) pointing toward the fluorescent layer. A method for manufacturing a field emission display is also provided.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of part of an FED according to an exemplary embodiment of the present invention.

FIGS. 2-4 are sectional views showing sequential stages of an exemplary method for manufacturing the FED of FIG. 1.

FIG. 5 is a cross-sectional view of a pixel region of a conventional FED.

FIGS. 6-11 are sectional views of one pixel region, showing sequential stages in a process of manufacturing the FED of FIG. 5.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made to the drawings to describe preferred and exemplary embodiments in detail.

Referring to FIG. 1, this is a schematic, cross-sectional view of an FED according to an exemplary embodiment of the present invention. The FED 20 includes a first substrate 21, a second substrate 22, a metal layer 210, a transparent electrode 221, a fluorescent layer 223, and a poly-silicon layer 212 having a plurality of tips 218.

The first substrate 21 may be transparent or opaque, and the second substrate 22 is transparent. The first and second substrates 21 and 22 are disposed parallel to and spaced apart from each other. The metal layer 210 is disposed on an inner surface of the first substrate 21, and is made of aluminum. The metal layer 210 functions as a cathode. The poly-silicon layer 212 is disposed on the metal layer 210. The poly-silicon layer 212 with the tips 218 is formed by an excimer laser micromachining process. In such process, an amorphous silicon layer is converted into the poly-silicon layer 212 via a crystallization process. The tips 218 are spaced apart at regular intervals, and point toward the fluorescent layer 223. The tips 218 are used as electron-emitting sources.

The transparent electrode 221 is disposed on an inner surface of the second substrate 22, and is made of indium tin oxide or indium zinc oxide. The electrode layer 221 functions as an anode. The fluorescent layer 223 is disposed on the transparent electrode 221. The fluorescent layer 223 includes red fluorescent material selected from Y₂O₃:Eu and Y₂O₂S:Eu, green fluorescent material selected from SrGa₂S₄:Eu, Y₂SiO₅:Tb, and ZnS:(Cu, Al), and blue fluorescent material selected from Y₂SiO₅:Ce and ZnS:Ag.

After assembly, a region between the first and second substrates 21, 22 is in a vacuum state, and a distance between the metal layer 210 and the transparent electrode 221 is in the range from 0.2 mm to 1.0 mm. In operation, a voltage is applied to the cathode metal layer 210 and the anode transparent electrode 221, so as to enable the tips 218 to emit electrons. Then the electrons impinge the fluorescent powder of the fluorescent layer 223 to generate red, green, and/or blue light beams, for displaying of images.

As detailed above, the tips 218 of the poly-silicon layer 212 are used as the electrons-emitting sources of the FED 20, and the tips 218 are formed by an excimer laser micromachining process. In this micromachining process, there is no metallic material needed. In particular, unlike with a conventional FED, there is no wastage of valuable metals such as Cr, Cb, and Mo. Therefore the FED 20 can be obtained at a substantially reduced cost.

Referring to FIGS. 2-4, these are schematic, sectional views showing sequential stages of an exemplary method for manufacturing the FED 20. The method includes the following steps:

FIG. 2 shows the initial stage of providing a first substrate 21, which may be transparent or opaque. A metal layer 210 is applied on the first substrate 21 via a physical vapor deposition process. A thickness of the metal layer 210 is in the range from 50 nanometers (nm) to 500 nm. Preferably, the metal layer 210 is made of aluminum.

In the next step illustrated in FIG. 3, an amorphous silicon layer 219 is applied on the metal layer 210 via a chemical vapor deposition process. During the chemical vapor deposition process, the gas source is SiH₄+H₂+PH₃, and the treating temperature is in the range from 100° C. to 500° C. The amorphous silicon layer 219 is a heavily doped amorphous silicon layer, with a thickness in the range from 30 nm to 200 nm.

FIG. 4 illustrates the step of forming a poly-silicon layer 212 with a plurality of tips 218. The amorphous silicon layer 219 is crystallized into the poly-silicon layer 212 via an excimer laser micromachining process. During the excimer laser micromachining process, a plurality of tips 218 is formed on a surface of the poly-silicon layer 212 simultaneously.

The metal layer 210 is used as a cathode. That is, by performing the above-described steps, a cathode substrate is obtained. An exemplary process for manufacturing an anode substrate is as follows:

A second substrate 22 is provided, which is a transparent substrate. A transparent electrode 221 is formed on a surface of the second substrate 22 via a physical vapor deposition process. A thickness of the transparent electrode 221 is in the range from 20 nm to 100 nm. The transparent electrode 221 is made of indium tin oxide or indium zinc oxide. After that, a fluorescent layer 223 is coated on the transparent electrode 221.

In the final step, the first and second substrates 21, 22 are attached together, with the tips 218 pointing toward the fluorescent layer 223. The first and second substrates 21, 22 are parallel to and spaced apart from each other a predetermined distance. A region between the first and second substrates 21, 22 is in a vacuum state. A distance between the metal layer 210 and the transparent electrode 221 is in the range from 0.2 mm to 1.0 mm.

Unlike with conventional FEDs, the tips 218 of the poly-silicon layer 212 are formed by crystallizing the amorphous silicon layer 219 using excimer laser micromachining technology. The process for manufacturing the FED 20 is simple and inexpensive.

It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.

Claims

1. A field emission display, comprising: a first substrate;a second substrate, the first and second substrates being at opposite sides of the field emission display;a metal layer disposed on an inner surface of the first substrate;a transparent electrode disposed on an inner surface of the second substrate, and spaced apart from the metal layer;a fluorescent layer disposed on the transparent electrode; anda poly-silicon layer disposed on the metal layer, the poly-silicon layer defining a plurality of tips pointing toward the fluorescent layer.

2. The field emission display as claimed in claim 1, wherein the poly-silicon layer with the tips thereof is formed by an excimer laser micromachining process.

3. The field emission display as claimed in claim 1, wherein a distance between the metal layer and the transparent electrode is in the range from approximately 0.2 mm to approximately 1.0 mm.

4. The field emission display as claimed in claim 1, wherein the metal layer is made of aluminum, and the transparent electrode is made of at least one of indium tin oxide and indium zinc oxide.

5. The field emission display as claimed in claim 1, wherein the fluorescent layer comprises red fluorescent material selected from Y2O3:Eu and Y2O2S:Eu, green fluorescent material selected from SrGa2S4:Eu, Y2SiO5:Tb, and ZnS:(Cu, Al), and blue fluorescent material selected from Y2SiO5:Ce and ZnS:Ag.

6. The field emission display as claimed in claim 1, wherein the second substrate is transparent.

7. A method for manufacturing a field emission display, comprising: providing a first substrate;forming a metal layer on the first substrate;forming an amorphous silicon layer on the metal layer;treating the amorphous silicon layer to form a poly-silicon layer with a plurality of tips;providing a second substrate;forming a transparent electrode on the second substrate;forming a fluorescent layer on the transparent electrode; andattaching the first and second substrates together such that the tips point toward and are spaced apart from the fluorescent layer.

8. The method as claimed in claim 7, wherein the poly-silicon layer with the plurality of tips is formed by an excimer laser micromachining process.

9. The method as claimed in claim 7, wherein the metal layer is applied on the first substrate via a physical vapor deposition process.

10. The method as claimed in claim 9, wherein the metal layer comprises aluminum, and has a thickness in the range from approximately 50 nm to approximately 500 nm.

11. The method as claimed in claim 7, wherein the amorphous silicon layer is applied on the metal layer via a chemical vapor deposition process.

12. The method as claimed in claim 11, wherein a gas source in the chemical vapor deposition process is SiH4+H2+PH3.

13. The method as claimed in claim 12, wherein a temperature of the chemical vapor deposition process is in the range from approximately 100° C. to approximately 500° C.

14. The method as claimed in claim 11, wherein a thickness of the amorphous silicon layer is in the range from approximately 30 nm to approximately 200 nm.

15. The method as claimed in claim 7, wherein the transparent electrode is applied on the second substrate via a chemical vapor deposition process.

16. The method as claimed in claim 15, wherein the transparent electrode is made of indium tin oxide or indium zinc oxide, and a thickness of the transparent electrode is in the range from approximately 20 nm to approximately 100 nm.

17. The method as claimed in claim 7, wherein the fluorescent layer comprises red fluorescent material selected from Y2O3:Eu and Y2O2S:Eu, green fluorescent material selected from SrGa2S4:Eu, Y2SiO5:Tb, and ZnS:(Cu, Al), and blue fluorescent material selected from Y2SiO5:Ce and ZnS:Ag.

18. The method as claimed in claim 7, wherein a region between the first and second substrates is in a vacuum state after the first and second substrates are attached together, and a distance between the transparent electrode and the metal layer is in the range from approximately 0.2 mm to approximately 1.0 mm.

19. A field emission display comprising: a first substrate;a second substrate, the first and second substrates being at opposite sides of the field emission display;a metal layer disposed on an inner surface of the first substrate;a transparent electrode disposed on an inner surface of the second substrate, and spaced apart from the metal layer;a fluorescent layer disposed on the transparent electrode; anda poly-silicon layer disposed on the metal layer, the poly-silicon layer being uneven.