JP2006156098A - Cathode substrate, electron source substrate, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device which can attain enlargement of a screen with lower manufacturing cost compared to that of conventional type. <P>SOLUTION: The display device 10 includes a cathode substrate 20, an electron extractor substrate 30, an anode 40 and a spacer 50, wherein: the cathode substrate 20 includes a glass substrate 21, an electron emitting electrode 22 provided on a bottom surface of a groove 21a formed on the glass substrate 21, and a graphite nanofiber 23 formed on the electron emitting electrode 22; the electron extractor substrate 30 includes a glass substrate 31, an electron extractor electrode 32, formed on the glass substrate 31, which extracts electrons from the graphite nanofiber 23; and the anode 40 includes a glass substrate 41, an anode electrode 42, formed on the glass substrate 41, which captures electrons, and a phosphor layer 43 which emits light by electron collision. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cathode substrate, an electron source substrate, and a display device that emit electrons by an applied electric field.

  Conventionally, such a display device as shown in FIG. 5 is known. A conventional display device 1 shown in FIG. 5 includes an electron source substrate 2 and an anode 3, and the electron source substrate 2 includes an electron emission electrode 2 b formed on a glass substrate 2 a, a carbon nanotube, or a graphite nanoparticle. An electron emission portion 2c formed of a fiber, an insulating layer 2d formed on the electron emission electrode 2b, and an electron extraction electrode 2e that draws electrons from the electron emission portion 2c are provided. The anode 3 is formed on the glass substrate 3a. An anode electrode 3b that is formed and captures electrons, and a phosphor layer 3c that emits light by collision of electrons. The insulating layer 2d provides electrical insulation between the electron emission electrode 2b, the electron emission portion 2c, and the electron extraction electrode 2e. In this configuration, the phosphor layer 3c is caused to emit light by causing the anode to capture electrons emitted by the electric field applied between the electron emission electrode 2b and the electron extraction electrode 2e (for example, , See Non-Patent Documents 1 to 3.).

As a conventional method for manufacturing the display device 1, first, a catalyst layer for generating the electron emission electrode 2b and the electron emission portion 2c is formed on the glass substrate 2a and then patterned. Next, for example, SiO ₂ is formed by vapor deposition or sputtering to form an insulating layer 2d. Further, an electron extraction electrode 2e is formed thereon and then patterned. Thereafter, an opening is formed in the insulating layer 2d by etching to expose the catalyst layer, and then an electron emission portion 2c is formed in the electron emission electrode 2b by the CVD method, whereby the electron source substrate 2 is obtained. The electron source substrate 2 and the anode 3 are arranged to face each other at a predetermined interval, frit sealing is performed, and the inside of the panel is evacuated to obtain the display device 1.
S. Uemura, et al. "Large Size FED with Carbon Nanotubes Emitter", SID '02, pp. 1132-1135 (2002) S. Kang, et al. , "Low Temperature Carbon Nanotubes for Triode-Type Field-Emitter Array", SID '03, pp. 802-805 (2003) M.M. Hirakawa, et al. , "Fabrication of a structure Structure Graphite nanofiber FED by Thermal CVD Method", IDW '02, pp. 199-001. 1065-1068 (2002)

However, in such a conventional display device, SiO ₂ is generally used as the insulating layer 2d, and the difference between the thermal expansion coefficients of SiO ₂ and the glass substrate 2a is large. In the process of forming the electron emission portion 2c on the electron emission electrode 2b by the CVD method, the sealing process of the electron source substrate 2 and the anode 3 and the vacuum evacuation process, etc., the insulating layer 2d is cracked or peeled off. There is a problem that the manufacturing cost increases due to a decrease in the temperature.

Further, in the conventional display device, as the screen becomes larger, it becomes difficult to form the SiO ₂ film with the required film thickness accuracy, and the electrical connection between the electron emission electrode 2b and the electron extraction electrode 2e is difficult. There is a problem that it is difficult to increase the size of the screen because a pinhole that causes a mechanical short circuit is likely to occur.

  The present invention has been made to solve such problems, and provides a cathode substrate, an electron source substrate, and a display device capable of increasing the size of the screen at a lower manufacturing cost than the conventional one. It is.

  The cathode substrate of the present invention includes a substrate having a groove formed thereon and electron emission means for emitting electrons when a predetermined electric field is applied, and the groove is formed on one surface of the substrate, The electron emission means has a configuration characterized in that it is provided inside the groove.

With this configuration, the cathode substrate of the present invention eliminates the insulating layer formed of SiO ₂ and can apply an electric field to the electron emission means using the step of the groove as an insulating layer. To avoid defects such as cracks, peeling and pinholes, ensuring high film formation accuracy, and lowering the production yield, and making the screen larger at a lower manufacturing cost than conventional ones. Can do.

  The cathode substrate of the present invention has a configuration characterized in that the electron emission means is formed of a carbon-based material.

  With this configuration, the cathode substrate according to the present invention is capable of emitting electrons at a relatively low voltage because the electron emitting means for emitting electrons is formed of a carbon-based material, and follows the conventional manufacturing method as it is. Therefore, the manufacturing cost can be kept lower than the conventional one.

  Furthermore, the electron source substrate of the present invention comprises a cathode substrate and an electron extraction electrode that applies the electric field and extracts the electrons from the electron emission means, and the electron extraction electrode has a predetermined distance from the cathode substrate. In this case, the structure is characterized in that they are arranged opposite to each other.

  With this configuration, the electron source substrate of the present invention can apply an electric field to the electron emission means using the step of the groove of the cathode substrate as an insulating layer in the electron extraction electrode, so that the insulating layer has been cracked and peeled off. In addition, problems such as defects such as pinholes, ensuring high film formation accuracy, and a decrease in manufacturing yield can be avoided, and the screen can be enlarged at a lower manufacturing cost than conventional ones.

  Furthermore, the display device of the present invention includes an electron source substrate and an anode for capturing the electrons, and the anode is located on a side different from the side on which the cathode substrate is provided with respect to the extraction electrode. To each other with a predetermined distance from each other.

  With this configuration, in the display device of the present invention, the electron extraction electrode applies an electric field to the electron emission means using the step of the groove of the cathode substrate as an insulating layer, and the anode captures the electrons emitted from the electron emission means. It is possible to avoid problems such as cracks, peeling, pinholes, etc. of the insulating layer that occurred, ensuring high film formation accuracy, lowering manufacturing yield, etc., and screens at a lower manufacturing cost than conventional ones Can be increased in size.

  The present invention can provide a cathode substrate, an electron source substrate, and a display device that have the effect that the screen can be enlarged at a lower manufacturing cost than the conventional one.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the structure of the display device of this embodiment will be described.

  As shown in FIG. 1A, the display device 10 according to the present embodiment includes a cathode substrate 20, an electron extraction substrate 30, an anode 40, and a spacer 50. The cathode substrate 20 and the electron extraction substrate 30 constitute an electron source substrate of the present invention.

  The cathode substrate 20 includes a glass substrate 21, an electron emission electrode 22 provided on the bottom surface of the groove 21 a formed in the glass substrate 21, and a graphite nanofiber (hereinafter referred to as electron emission means) formed on the electron emission electrode 22. "GNF") 23. The electron extraction substrate 30 includes a glass substrate 31 and an electron extraction electrode 32 that is formed on the glass substrate 31 and extracts electrons from the GNF 23.

  FIG. 1B is a plan view of the cathode substrate 20 and the electron extraction substrate 30 as viewed from the anode 40 side. As shown in FIG. 1B, a groove 21a is formed in the glass substrate 21 of the cathode substrate 20, and an electron emission electrode 22 is provided on the groove 21a. The illustration of GNF 23 is omitted.

  The glass substrate 31 of the electron extraction substrate 30 is provided with an opening 31a through which electrons pass and electron extraction electrodes 32 at a predetermined interval in a direction perpendicular to the groove 21a. The direction of the groove 21a is hereinafter referred to as “vertical direction”, and the direction orthogonal to this direction is hereinafter referred to as “lateral direction”.

  The anode 40 includes a glass substrate 41, an anode electrode 42 that is formed on the glass substrate 41 and captures electrons, and a phosphor layer 43 that emits light by collision of electrons.

  The electron emission electrode 22 and the electron extraction electrode 32 are made of chromium having a thickness of about 100 to 300 nm, for example. An electron extraction voltage is applied between the electron emission electrode 22 and the electron extraction electrode 32, and an anode voltage is applied between the electron emission electrode 22 and the anode electrode 42.

  The anode electrode 42 is constituted by a transparent electrode such as ITO (Indium Tin Oxide), and the phosphor layer 43 is formed by applying a phosphor on the anode electrode 42.

  The spacer 50 is made of, for example, glass or ceramics, and the interval between the electron extraction substrate 30 and the anode 40 is set to, for example, about 0.5 mm to 2 mm.

  Next, a method for manufacturing the display device 10 of the present embodiment will be described.

  Initially, the manufacturing method of the cathode substrate 20 is demonstrated using FIG.

  First, as shown in FIG. 2A, the photoresist layer 61 is patterned on the glass substrate 21 so as to have a vertical stripe shape.

  Next, the glass substrate 21 is wet-etched with, for example, a hydrofluoric acid aqueous solution to form the grooves 21a. At this time, the glass substrate 21 is side-etched laterally beyond the range of the photoresist layer 61, and a groove 21a as shown in FIG. 2B is obtained. The groove 21a is formed with a depth of about 5 μm, for example.

  Subsequently, as shown in FIG. 2C, an electron emission electrode film 62 is formed from above the photoresist layer 61 using, for example, chromium. The electron emission electrode film 62 is formed with a film thickness of, for example, about 0.2 μm to 0.3 μm.

  Further, as shown in FIG. 2D, a catalyst layer 63 is formed on the electron emission electrode film 62. The catalyst layer 63 is formed with a film thickness of about 10 nm using, for example, an iron-based alloy. As the iron-based alloy, for example, an alloy of 42% nickel, 6% chromium, and 52% iron is used.

  Next, the photoresist layer 61 is peeled off, and the electron emission electrode film 62 and the catalyst layer 63 formed on the photoresist layer 61 are also removed. As a result, as shown in FIG. 2E, the electron emission electrode film 62 and the catalyst layer 63 are formed on the bottom surface of the groove 21a.

  Then, as shown in FIG. 2 (f), for example, by CVD (Chemical Vapor Deposition), an electron emission electrode in which a fine fibrous GNF 23 made of carbon is formed of an electron emission electrode film 62 is formed. Thus, the cathode substrate 20 is obtained. This step by the CVD method is performed, for example, under conditions where the set temperature is 550 ° C. to 800 ° C. and the reaction time is 5 minutes to 20 minutes. Note that the GNF 23 can be formed at any location on the electron emission electrode 22 by patterning the catalyst layer 63 with a pattern different from that of the electron emission electrode film 62.

  Next, a method for manufacturing the electron extraction substrate 30 will be described. As shown in FIG. 1B, the electron extraction substrate 30 is formed by forming an electron extraction electrode 32 in a lateral direction on a glass substrate 31 provided with an opening 31a in advance. The electron extraction electrode 32 is formed of chromium having a thickness of about 100 to 300 nm, for example. The opening 31a can be formed by a sand blast method, or can be formed by photoetching using photosensitive glass as the glass substrate 31.

  Next, a method for manufacturing the anode 40 will be described. As shown in FIG. 1A, the anode 40 is formed by first depositing, for example, ITO on a glass substrate 41 by a sputtering method or a vapor deposition method to form an anode electrode 42. Then, the phosphor is applied on the anode electrode 42 to form the phosphor layer 43, whereby the anode 40 is obtained.

  The cathode substrate 20, the electron extraction substrate 30, and the anode 40 manufactured as described above are first fixed with the cathode substrate 20 and the electron extraction substrate 30 facing each other to obtain an electron source substrate. Then, the electron source substrate and the anode 40 are fixed by the spacer 50, sealed and evacuated, and then the chip is turned off to obtain the display device 10.

  Note that the materials, dimensions, methods, and the like shown in the manufacturing method described above are examples, and the present invention is not limited to these.

  For example, carbon nanotubes may be formed on the anode electrode 42 instead of the GNF 23. Further, in the step of forming the groove 21a shown in FIG. 2B, a processing method such as sand blasting or dry etching using a reactive gas can be selected instead of the wet etching described above. By selecting and combining the processing methods, the aspect ratio of the groove 21a, the dimension of side etching, and the like can be arbitrarily set, so that the groove 21a can be formed into a desired shape.

  Furthermore, the electron extraction substrate 30 can be changed to that shown in FIGS. 3 and 4, which will be described below. FIGS. 3A and 3B are a side sectional view and a plan view showing an example in which the electron extraction substrate includes one circular window, and FIG. 3C shows a plurality of electron extraction substrates. It is a top view which shows the example provided with this circular window (a side sectional view is omitted). FIGS. 4A and 4B are a side sectional view and a plan view, respectively, showing an example in which the electron extraction substrate is made of a wire.

  First, the electron extraction substrate 70 shown in FIGS. 3A and 3B includes a glass substrate 71 and an electron extraction electrode 72, and the electron extraction electrode 72 has a circular through hole 71 a through which electrons pass. Is formed. With the structure in which the circular through hole 71a is formed, the electron extraction substrate 70 can uniformly extract electrons from the electron emission electrode 22 while maintaining the strength of the glass substrate 71.

  3C includes a glass substrate 81 and an electron extraction electrode 82, and the electron extraction electrode 82 has a plurality of through holes 81a through which electrons pass. . The electron extraction substrate 80 can extract electrons from the electron emission electrode 22 while maintaining the strength of the glass substrate 81 by the structure in which the plurality of through holes 81 a are formed, and facilitates alignment with the cathode substrate 20. be able to.

  Furthermore, the electron extraction substrate 90 shown in FIGS. 4A and 4B is composed of a plurality of metal wires 91 as electron extraction electrodes. Since the electron extraction substrate 90 is provided with a plurality of metal wires 91 in parallel at a predetermined pitch, more electrons can be extracted than the electron extraction substrate 70 described above. The plurality of metal wires 91 can be made of a material having a thermal expansion coefficient combined with that of the glass substrate 21, for example, a 426 alloy.

  Next, the operation of the display device 10 according to the present embodiment will be described with reference to FIG.

  First, an electron extraction voltage is applied between the electron emission electrode 22 and the electron extraction electrode 32, and an anode voltage is applied between the electron emission electrode 22 and the anode electrode 42. For example, a voltage of about 20 V to 60 V is applied as the electron extraction voltage, and a voltage of about 200 V to 2 kV is applied as the anode voltage.

  Next, electrons are emitted from the GNF 23 by an electric field generated by an electron extraction voltage. The electrons emitted from the GNF 23 are accelerated by the electric field due to the anode voltage, pass through the phosphor layer 43, and the phosphor layer 43 emits light, and then reach the anode electrode 42.

  As described above, according to the display device 10 of the present embodiment, the electron extraction substrate 30 draws electrons by applying an electric field to the GNF 23 using the step of the groove 21a of the cathode substrate 20 as an insulating layer. Since the configuration is such that the electrons emitted from the GNF 23 are accelerated and captured, defects such as cracks, peeling, pinholes, etc. of the insulating layer that have occurred in the past, ensuring high film formation accuracy, lowering the manufacturing yield, etc. Problems can be avoided, and the screen can be enlarged at a lower manufacturing cost than the conventional one.

Further, according to the display device 10 of the present embodiment, the step of the groove 21a of the cathode substrate 20 is used as an insulating layer, and the conventional insulating layer formed of SiO ₂ is eliminated. The distance between the electrodes can be set with higher accuracy than the conventional one, and variations in the electron emission voltage can be reduced to realize stable electron emission. Specifically, when setting the distance between the electron emission electrode and the electron extraction electrode, the conventional one is affected by the variation in the thickness of the insulating layer and the variation in the etching dimension that exposes the catalyst layer. This is because the cathode substrate 20 according to the present embodiment is configured to be affected only by the variation in the etching dimension of the groove 21a.

Further, according to the display device 10 of the present embodiment, the step of the groove 21a of the cathode substrate 20 is used as an insulating layer, and the SiO ₂ film forming process used in the conventional one is abolished. With the increase in size, it is not necessary to introduce a large SiO ₂ film forming apparatus, and the screen can be enlarged with less equipment investment.

  Moreover, according to the display device 10 of the present embodiment, the electron emission means for emitting electrons is formed of a carbon-based material, and electrons can be emitted from the cathode substrate 20 with a relatively low electron extraction voltage. Therefore, power saving can be achieved, and the conventional manufacturing method can be followed as it is, so that the manufacturing cost can be kept lower than that of the conventional one.

(A) Side surface sectional view showing the configuration of the display device of the present invention (b) Plan view of the electron source substrate and the electron extraction portion according to the display device of the present invention Manufacturing process diagram of electron source substrate according to display device of the present invention (A) Side sectional view showing an example in which the electron extraction substrate according to the display device of the present invention has one circular window (b) Example in which the electron extraction substrate according to the display device of the present invention has one circular window (C) The top view which shows the example in which the electronic extraction board | substrate which concerns on the display apparatus of this invention was provided with several circular windows (A) Side surface sectional view showing an example in which the electron extraction substrate according to the display device of the present invention is configured by a wire (b) Plan view showing an example in which the electron extraction substrate according to the display device of the present invention is configured by a wire Side sectional view showing the configuration of a conventional display device

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Display apparatus 20 Cathode substrate 21, 31, 41, 71, 81 Glass substrate 21a Groove 22 Electron emission electrode 23 GNF (electron emission means)
30, 70, 80, 90 Electron extraction substrate 31a Opening portion 32, 72, 82 Electron extraction electrode 40 Anode 42 Anode electrode 43 Phosphor layer 50 Spacer 61 Photoresist layer 62 Electron emission electrode film 63 Catalyst layer 71a, 81a Through hole 91 Metal wire

Claims (4)

A substrate on which a groove is formed; and an electron emitting means that emits electrons when a predetermined electric field is applied. The groove is formed on one surface of the substrate, and the electron emitting means is formed on the groove. A cathode substrate characterized by being provided in the interior of the substrate. The cathode substrate according to claim 1, wherein the electron emission means is made of a carbon-based material. A cathode substrate according to claim 1 or 2 and an electron extraction electrode for extracting the electrons from the cathode substrate, wherein the electron extraction electrode is disposed opposite to the cathode substrate at a predetermined interval. An electron source substrate characterized by. 4. An electron source substrate according to claim 3, and an anode for accelerating and capturing the electrons emitted from the electron source substrate, wherein the anode is provided on a side on which the cathode substrate is provided with respect to the extraction electrode. A display device, wherein the display device is disposed opposite to the lead electrode at a predetermined distance from the lead electrode.

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