Patent Publication Number: US-8125470-B2

Title: Electron source, image display apparatus, and information display reproducing apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to an electron source that is used for a television set, a display of a computer, and an electron beam drawing apparatus or the like, an image display apparatus, and an information display reproducing apparatus. 
     BACKGROUND ART 
     In recent years, an FED (a field emission display) has drawn attention. The FED is generally provided with an RP (a rear plate) having a field emission type electron-emitting device arranged thereon in response to each pixel arranged in a two-dimensional matrix and an FP (face plate) having a light emitting layer that emits a light due to a crash of electrons emitted from an electron-emitting device on the RP. Then, the FP and the RP are opposed with each other to be separated by a spacer. A pressure between the FP and the RP is reduced to a pressure that is lower than atmosphere pressure (a vacuum). 
     As an electron-emitting device, a vertical field emission type electron-emitting device, having a cathode electrode and a gate electrode provided with an opening formed on a surface of a substrate in a vertical direction, may be considered. Then, as an opening shape of the gate electrode seen from the side of the FP, a slit-like (according to a typical example, a rectangular figure) opening and a hole-like (according to a typical example, a circular figure) opening may be considered. 
     As a vertical field emission type electron-emitting device having an electron beam convergent function, an example of an electron-emitting device having a cathode electrode provided with an electron-emitting portion and a gate electrode arranged on a surface of a substrate in a vertical direction at intervals, is disclosed in Japanese Patent Application Laid-Open No. 8-096703. 
     In addition, an example such that vertical field emission type electron-emitting devices are arranged in a matrix on an intersecting portion of a scanning wiring with a signal wiring is disclosed in JP-A No. 2003-151456. 
     DISCLOSURE OF INVENTION 
     In the case of the FED, in order to maintain an interval between the RP and the FP, a spacer may be disposed on a scanning wiring or on a signal wiring. Here, an electron beam emitted from an electron-emitting device is spread, so that the electron beam emitted from the electron-emitting device may be irradiated to the spacer. Then, various problems may be generated, for example, an orbit of an electron beam is changed because the spacer is charged up and an electron-emitting device breaks down because of a creeping discharge due to lowering of a creeping withstand voltage of the spacer. 
     There is a problem such that a high-definition FED cannot be realized if the electron-emitting devices are sparsely arranged in order to avoid such a problem. 
     The present invention has been made taking the foregoing problems into consideration and an object of which is to provide a technique to realize a high-definition field emission type display by reducing spread of an electron beam to be emitted from an electron-emitting device in the vicinity of a first wiring so as to prevent irradiation of the electron beam to a spacer arranged on the first wiring. 
     The present invention employs the following configuration, namely, the configuration comprising: a substrate; a first wiring that is arranged on the substrate; a second wiring that is arranged on the substrate and intersects with the first wiring; and an electron-emitting device having a cathode electrode provided with an electron-emitting member and a gate electrode arranged above the cathode electrode, which is arranged on the substrate and is separated from an intersecting portion of the first wiring with the second wiring; wherein the first wiring is arranged on the second wiring via an insulating layer; the gate electrode is provided with a plurality of slit-like openings that is arranged at intervals; and the opening is arranged so that an extended line in a longitudinal direction thereof intersects with the first wiring. 
     In addition, the present invention employs the following configuration, namely, the configuration comprising: a substrate; a first wiring that is arranged on the substrate; a second wiring that is arranged on the substrate and intersects with the first wiring; and an electron-emitting device having a cathode electrode provided with an electron-emitting member and a gate electrode arranged above the cathode electrode, which is arranged on the substrate and is separated from an intersecting portion of the first wiring with the second wiring; wherein the first wiring is arranged on the second wiring via an insulating layer; the gate electrode is provided with a plurality of slit-like openings that is arranged at intervals; and the slit-like opening is arranged so that one end portion in a longitudinal direction thereof near the first wiring rather than a center portion in a longitudinal direction. 
     According to the present invention, by reducing spread of an electron beam to be emitted from an electron-emitting device in the vicinity of a first wiring, it is possible to prevent irradiation of the electron beam to a spacer arranged on the first wiring, and further, it is possible to realize a high-definition field emission display. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a plan view of an electron source according to an embodiment of the present invention; 
         FIG. 1B  is a cross sectional view taken on a line A-A′ of  FIG. 1A ; 
         FIG. 1C  is a cross sectional view taken on a line B-B′ of  FIG. 1A ; 
         FIG. 2  is a cross sectional view showing an electron source according to the embodiment of the present invention; 
         FIGS. 3A to 3H  are views showing a manufacturing method of the electron source according to the embodiment of the present invention; 
         FIG. 4  is a view showing a configuration of an image display apparatus according to the embodiment of the present invention; 
         FIG. 5  is a view showing a configuration of a fluorescent film of the image display apparatus according to the embodiment of the present invention; 
         FIG. 6  is a view showing a configuration of an image receiving display apparatus using an electron-emitting device according to the embodiment of the present invention; 
         FIGS. 7A to 7J  are views showing a manufacturing method of an electron source according to a first embodiment of the present invention; 
         FIG. 8  is a view showing a cross section in a lateral direction of one opening shaped in a slit of an electron-emitting device according to the first embodiment of the present invention; 
         FIG. 9  is a view showing a constitutional example when the electron source according to the first embodiment of the present invention is operated; 
         FIGS. 10A to 10J  are views showing a manufacturing method of an electron source according to a second embodiment of the present invention; 
         FIG. 11  is a view showing a cross section in a longitudinal direction of one opening shaped in a slit of an electron-emitting device according to the second embodiment of the present invention; 
         FIGS. 12A to 12J  are views showing a manufacturing method of an electron source according to a third embodiment of the present invention; 
         FIG. 13  is a view showing a cross section in a longitudinal direction of one opening shaped in a slit of an electron-emitting device according to the third embodiment of the present invention; 
         FIG. 14  is a plan view of an electron source according to a fourth embodiment of the present invention; and 
         FIG. 15  is a plan view of an electron source according to a fifth embodiment of the present invention. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, with reference to the drawings, preferable embodiments of this invention will be described with an example in detail. However, the scope of the present invention is not limited by its measurement, its material, its shape, and its relative arrangement or the like of a component part described in this embodiment unless there is a specific description. 
     In the electron source according to the present invention, electron-emitting devices are arranged so as to be separated from an intersecting portion of a first wiring that is a scanning wiring with a second wiring that is a signal wiring. As an electron-emitting device, a vertical field emission type electron-emitting device having an electron-emitting member and a gate electrode provided with slit-like openings formed on a substrate is applied. Then, the slit-like openings of the gate electrode are arranged so that a extended lines in a longitudinal direction thereof intersect with the first wiring. In other words, one end portion in a longitudinal direction of the slit-like opening is arranged near the first wiring rather than a center portion in a longitudinal direction. 
     In the vertical field emission type electron-emitting device having the slit-like opening, a convergent effect of an electron beam is different in a longitudinal direction and in a lateral direction of the slit-like opening. 
     Spread of the electron beam in the longitudinal direction of the slit-like opening is decided by an electron emitted from the vicinity of the end portion in the longitudinal direction of the slit-like opening. In the vicinity of the longitudinal-directional end portion of the slit-like opening, the gate electrode is arranged so as to surround an electron-emitting portion 180° or more, so that spread of the electron beam as if the electron is emitted from a vertical field emission type electron-emitting device having a hole-like opening is obtained. 
     On the other hand, spread of the electron beam in the lateral direction of the slit-like opening is decided by the electron emitted from the center portion in the longitudinal direction of the slit-like opening. In the vicinity of the center portion in the longitudinal direction of the slit-like opening, the electron-emitting portion is only sandwiched by two faces of the gate electrode being opposed with each other. Therefore, the vertical field emission type electron-emitting device having the slit-like opening has a smaller convergent effect of the electron beam due to the gate electrode than that of the vertical field emission type electron-emitting device having the hole-like opening. In other words, spread of the electron beam to be emitted from the vertical field emission type electron-emitting device having the slit-like opening is larger than spread of the electron beam to be emitted from the vertical field emission type electron-emitting device having the hole-like opening. 
     In consideration of a cross section of the opening of the vertical field emission type electron-emitting device, in the case of the same opening width (in the case of the hole-like opening, an opening diameter), spread of the electron beam to be emitted from the vertical field emission type electron-emitting device of the hole-like opening is smaller than spread of the electron beam to be emitted from the vertical field emission type electron-emitting device of the slit-like opening. Accordingly, the spread of the electron beam in the longitudinal direction of the slit-like opening is smaller than the spread of the electron beam in the lateral direction of the slit-like opening. 
     Particularly, in the case of the vertical field emission type electron-emitting device having an electron beam convergent function between the electron-emitting member and the gate electrode, the convergent effect very strongly works on the spread of the electron beam, so that the spread of the electron beam in the longitudinal direction of the slit-like opening is made smaller than the spread of the electron beam in the lateral direction of the slit-like opening. This is because that the convergent effect of the electron beam is large and the spread of the electron beam can be kept smaller, since a configuration having an electron beam convergent function between the electron-emitting portion and the gate electrode is arranged so as to surround the electron-emitting portion 180° C. or more. On the other hand, on the center portion in the longitudinal direction of the slit-like opening, the configuration having the electron beam convergent function between the electron-emitting portion and the gate electrode is only arranged so as to sandwich the electron-emitting portion by two faces being opposed to the electron-emitting portion, so that the convergent effect of the electron beam is made smaller since the portion to be surrounded by the configuration is smaller as compared to the convergent effect of the electron beam emitted from the vicinity of the end portion in the longitudinal direction of the slit-like opening. Accordingly, the spread of the electron beam emitted from the center portion in the longitudinal direction of the slit-like opening is made larger as compared to the spread of the electron beam emitted from the vicinity of the end portion in the longitudinal direction of the slit-like opening. 
     According to the present embodiment, by arranging the extended line in a longitudinal direction of the slit-like opening of the gate electrode so as to intersect with the first wiring on which the spacer is disposed, the end portion in the longitudinal direction of the slit-like opening is allowed to be arranged near the first wiring rather than the center portion in a longitudinal direction of the slit-like opening. 
     Thereby, in the vicinity of the spacer arranged on the first wiring, an electron is emitted from the end portion in the longitudinal direction of the slit-like opening having small spread of the electron beam. Therefore, according to the electron-emitting device having the slit-like opening, it is possible to make spread of the electron beam toward the spacer arranged on the first wiring smaller and it is possible to reduce the electron beam to be irradiated to the spacer. Thereby, the high-definition FED can be realized. 
       FIG. 1A  is a schematic plan view of an electron source according to an embodiment of the present invention. Further,  FIG. 1B  is a cross sectional view taken on a line A-A′ of  FIG. 1A , and  FIG. 1C  is a cross sectional view taken on a line B-B′ of  FIG. 1A . In  FIG. 1A , a first wiring  11  is elongated in a horizontal direction of a paper face, and in  FIG. 1A , a second wiring  12  is elongated in a vertical direction of a paper face at a right angle to the first wiring  11  on a lower layer of the first wiring  11 . An insulating layer  13  mediates between the second wiring  12  and the first wiring  11 . On an insulating substrate  14 , the first wiring  11  and the second wiring  12  are formed. An electron-emitting device  15  is arranged being separated from the region where the first wiring  11  and the second wiring  12  intersect with each other, an cathode electrode is connected to the first wiring  11 , and a gate electrode is connected to the second wiring  12 . The electron-emitting device  15  is provided with two slit-like openings that are arranged in a line at intervals. 
       FIG. 2  shows a cross section of the electron-emitting device  15  of  FIG. 1A , and particularly, shows a cross section of one slit-like opening in the electron-emitting device  15 . In  FIG. 2 , a cathode electrode  21  is formed on the insulating substrate  14  as a first layer to be connected to the first wiring  11 . A gate electrode  22  is formed higher than the cathode electrode  21  as the highest layer of the insulating substrate  14  to be connected to the second wiring  12 . An insulating layer  23  is formed lower than the gate electrode  22 . An electron-emitting material  24  as an electron-emitting member is disposed on the cathode electrode  21 . A focusing electrode  25  is disposed on the electron-emitting material  24  and the upper layer of this focusing electrode  25  is the insulating layer  23 . 
     The focusing electrode  25  may be a part of the cathode electrode  21 . Together with the cathode electrode  21 , the focusing electrode  25  is connected to the first wiring  11 . 
     Manufacturing methods of an electron source according to the present embodiment shown in  FIGS. 1A to 1C  and  FIG. 2  will be descried with reference to  FIGS. 3A to 3H . Further, each of  FIGS. 3A to 3H  is a schematic plan view in each step and only shows one pixel area. 
     (Step 1) 
     At first, on the insulating substrate  14  having a surface sufficiently cleaned, the second wiring  12  is arranged ( FIG. 3A ). 
     The second wiring  12  may be formed by a general vacuum deposition technology such as a vapor deposition method and a sputter method or may be formed by a printing technology. A method for forming the second wiring  12  may be appropriately selected by necessary a film thickness and a wiring width. 
     The insulating substrate  14  on which the second wiring  12  is formed may be appropriately selected from among a quartz glass, a glass having an impurity content such as Na reduced, a soda lime glass, a laminated body having SiO 2  formed on a silicon substrate or the like by a sputter method or the like, or an insulating ceramic substrate such as aluminum oxide. 
     (Step 2) 
     Subsequently, the cathode electrode  21  is arranged at the side of the second wiring  12  and the cathode electrode  21  is separated from the second wiring  12 . Then, the electron-emitting material  24  is formed on the cathode electrode ( FIG. 3B ). 
     The size (of land) of the cathode electrode  21  and the size of the electron-emitting material  24  may be the same or may be different. In the case of forming a focusing electrode  25  formed in Step 3 ( FIG. 3C ) also in the area where the first wiring  11  is formed in Step 7 ( FIG. 3G ), the cathode electrode  21  and the electron-emitting material  24  may not be formed in the area where the first wiring  11  is formed. In addition, if a cathode electrode function for injecting an electron in the electron-emitting material  24  is given to the focusing electrode  25  to be formed in Step 3, a step for forming the cathode electrode  21  may be omitted in the present step 2. 
     The cathode electrode  21  is formed by a general vacuum deposition technology such as a CVD method, a vapor deposition method, and a sputter method. For example, the material of the cathode electrode  21  may be appropriately selected from among a metal or an alloy material such as Be, Mg, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al, Cu, Ni, Cr, Au, Pt, and Pd, a carbide such as TiC, ZrC, HfC, Tac, Sic, and WC, a boride such as HfB 2 , ZrB 2 , LaB 6 , CeB 6 , YB 4 , and GdB 4 , a nitride such as TiN, ZrN, and HfN, and a semiconductor or the like such as Si and Ge. The thickness of the cathode electrode  21  is defined in the range of several tens nm to several mm, and preferably, the thickness of the cathode electrode  21  is selected in the range of several tens nm to several μm. 
     The electron-emitting material  24  is formed by a general vacuum deposition technology such as a CVD method, a vapor deposition method, and a sputter method or a technology for dissolving an organic solvent by heat. The material for composing the electron-emitting material  24  will be appropriately selected from among graphite, fullerene, a fiber-like conductive material (including a carbon fiber such as a carbon nano-tube), an amorphous carbon, a diamond-like carbon, and a carbon and a carbon composition having a diamond dispersed, for example. Preferably, a carbon composition having a low work function is employed. A film thickness of the electron-emitting material  24  is defined in the range not more than several μm, and preferably, the film thickness of the electron-emitting material  24  is selected in the range not more than 150 nm. 
     (Step 3) 
     Subsequently, the focusing electrode  25  is formed on the cathode electrode  21  and the electron-emitting material  24  ( FIG. 3C ). 
     The focusing electrode  25  is formed by a general vacuum deposition technology such as a CVD method, a vapor deposition method, and a sputter method. The material of the focusing electrode  25  may be the same as the material of the cathode electrode  21  or a different material may be used. In addition, upon forming the focusing electrode  25 , the same vacuum deposition technology as that used for forming the cathode electrode  21  may be used or a different vacuum deposition technology may be used. 
     In addition, the lengths of the cathode electrode  21 , the electron-emitting material  24 , and the focusing electrode  25  in a direction in parallel with the longitudinal direction of the second wiring  12  may be formed so as to be the same with each other or may be differently formed. However, at least one of the cathode electrode  21 , the electron-emitting material  24 , and the focusing electrode  25  should reach the area where the first wiring is formed. 
     (Step 4) 
     Subsequently, the insulating layer  23  is formed on the area where the electron-emitting device is formed ( FIG. 3D ). 
     The insulating layer  23  may be formed by using any method if it can be arranged on a desired area. As an example, for example, masking the area where the electron-emitting device is formed except for the portion where the insulating layer  23  is arranged, the insulating layer  23  can be formed by a general vacuum deposition technology such as a CVD method, a vapor deposition method, a sputter method, and a plasma method. Alternatively, by using a printing method such as an inkjet system, the insulating layer  23  can be arranged only on a desired area. 
     The insulating layer  23  is formed by a general vacuum deposition technology such as a sputter method, a CVD method, and a vapor deposition method. The material of the insulating layer  23  will be appropriately selected from among SiO 2 , SiN, Al 2 O 3 , Ta 2 O 5 , and CaF or the like. As the material of the insulating layer  23 , a material that can be stand up to a high electric field (namely, a material having high voltage tightness) is desirable. A film thickness of the insulating layer  23  is defined in the range of several tens nm to several μm, and preferably, the film thickness of the insulating layer  23  is selected in the range of several hundreds nm to several μm. 
     (Step 5) 
     Subsequently, the gate electrode  22  is formed on the area where the electron-emitting device is formed so as to be connected to the second wiring formed in Step 1 ( FIG. 3E ). 
     The material of the gate electrode  22  may be the same as the material of the cathode electrode  21  or the material of the focusing electrode  25  described in Step 2 or it may be different material. In addition, the gate electrode  22  may be formed by using the same method as the method for forming the cathode electrode  21  or the method for forming the focusing electrode  25  or the gate electrode  22  may be formed by using a different method. 
     (Step 6) 
     Subsequently, the insulating layer  13  having a contact hole  13   a  is formed on the area where the first wiring is formed ( FIG. 3F ). 
     The contact hole  13   a  is a square hole and the contact hole  13   a  serves to joint the first wiring  11 , the cathode electrode  21 , the electron-emitting material  24 , and the focusing electrode  25 . 
     The insulating layer  13  is formed by a general vacuum deposition technology such as a CVD method, a vapor deposition method, and a sputter method or a printing technology. A thickness and a width of a film necessary for the insulating layer  13  will be appropriately selected depending on a dielectric constant of the insulating layer  13 . 
     (Step 7) 
     Subsequently, the first wiring  11  is formed ( FIG. 3G ). 
     The first wiring  11  may be formed by a general vacuum deposition technology such as a vapor deposition method and a sputter method or may be formed by a printing technology. The first wiring  11  may be formed by the same method as the method for forming the second wiring  12  or may be formed by a different method. In addition, the material of the first wiring  11  may be the same as that of the second wiring  12  or may be a different material. The method for forming the first wiring  11  and the material of the first wiring  11  will be appropriately selected depending on a necessary thickness of the film and a necessary width of the wiring. 
     (Step 8) 
     Finally, a slit-like opening  30  is formed on the area where the electron-emitting device is formed so that the surface of the electron-emitting material  24  is exposed (FIG.  3 H). Through the above-described steps, an electron source of the present embodiment is completed. 
     In this case, the slit-like opening  30  is formed so that the extended line in a longitudinal direction of the slit-like opening  30  intersects with the first wiring  11  or the end portion in the longitudinal direction of the slit-like opening  30  is allowed to be arranged near the first wiring  11  rather than the center portion in a longitudinal direction of the slit-like opening  30 . 
     Further, in  FIG. 3H , the number of the slit-like openings  30  is two, however, the number of the openings  30  will be appropriately decided depending on the work function of the electron-emitting material  24 , a voltage upon driving the electron source, and a shape of an electron beam to be required or the like. In addition, a distance between the opposite gate electrodes  22  (the opening diameter) will be appropriately decided depending on a distance between the materials to form the electron-emitting device, a work function of the electron-emitting material  24 , a voltage upon driving the electron source, and a shape of an electron beam to be required or the like. Normally, the depth of the slit-like opening  30  is defined in the range of several tens nm to several tens μm, and preferably, it is selected in the range of not less than 100 nm and not more than 10 μm. Further, the slit-like opening  30  can be made into the rectangular opening  30 . Then, in this case, the length of a long side of the rectangular opening  30  is at least twice or more than the length of the short side practically, and preferably, it is five times or more than the length of the short side. 
     The slit-like opening  30  is formed so as to penetrate the gate electrode  22 , the insulating layer  23 , and the focusing electrode  25 . The opening  30  is formed by etching. The method of etching may be appropriately selected in response to the materials of the gate electrode  22 , the insulating layer  23 , and the focusing electrode  25  that are targets for etching. 
     Next, an application example of an electron source according to the embodiments of the present invention will be described below. By arranging a plurality of electron sources according to the embodiments of the present invention on a substrate, for example, an image display apparatus can be formed. 
     With reference to  FIG. 4 , the image display apparatus that is obtained by using the electron source according to the present embodiment will be described below. 
     A second wiring  41  and a first wiring  42  intersect with each other. An electron-emitting device  40  is arranged on an intersecting portion of the second wiring  41  with the first wiring  42  being separated from the second wiring  41  and the first wiring  42 . A face plate  46  is formed by a glass substrate  43 , a fluorescent film  44  that is a light-emitting member, and a metal back  45 . On an electron source substrate  47 , a plurality of electron-emitting devices  40  is arranged. A support frame  48  supports the face plate  46  and the electron source substrate  47  with intervening there between. An external package  49  is formed by the face plate  46 , the electron source substrate  47 , and the support frame  48 . 
     The second wiring  41  and the first wiring  42  can have a function as a row directional wiring and a column directional wiring, respectively, however, the second wiring  41  and the first wiring  42  may be connected to the row directional wiring and the column directional wiring, respectively. The face plate  46  is jointed to the support frame  48  by using a flit glass having a low melting point or the like. 
     In addition, by arranging at least one support body (not illustrated) that is referred to as a spacer between the face plate  46  and the electron source substrate  47 , the external package  49  having a sufficient intensity against an atmosphere pressure can be configured. In the case that the external package  49  is large, for example, a plurality of platy spacers is arranged on the first wiring  42  in order to obtain a sufficient intensity. 
     As described above, the image display apparatus is configured by the electron-emitting device  40  arranged on the electron source substrate  47 , the second wiring  41 , the first wiring  42 , and the external package  49 . 
       FIG. 5  schematically shows a part of the fluorescent film  44 . By regularly arranging a phosphor  51  corresponding to an emission color to be displayed and flashing a desired phosphor  51 , an image can be displayed on the outer face of the glass substrate  43 . The phosphor  51  is partitioned by a light absorption member  52 . An object of arranging the light absorption member  52  is to efface a mixed color or the like of each phosphor  51  corresponding to three primary colors that are required in a color display and to prevent degradation of a contrast or the like. For example, the phosphor  51  is arranged in the order of R (red), G (green), and B (blue) in an x direction, and the same color phosphor  51  is arranged in a y direction. The area where such a fluorescent film  44  is arranged becomes a screen of the image display apparatus. 
     An image receiving display apparatus as the information display reproducing apparatus according to the present embodiment is schematically shown in  FIG. 6 . The configuration of the image receiving display apparatus according to the present embodiment includes the image display apparatus having a screen schematically shown in  FIG. 4 . In  FIG. 6 , the image receiving display apparatus is configured by an image information receiver  61  as a receiver, an image signal generation circuit  62 , a driving circuit  63 , and an image display apparatus  64 . 
     At first, the image information receiver  61  outputs image information included in the received broadcast signal. The outputted image information is inputted in the image signal generation circuit  62  and an image signal is generated. As the image information receiver  61 , for example, a receiver such as a tuner which can tune and receive a radio broadcast, a cable broadcast, and a video broadcast via Internet or the like may be considered. The image information receiver  61  can receive not only the image information but also the character information and the voice information. Further, the image information receiver  61 , a TV set can configured together with the image signal generation circuit  62 , the driving circuit  63 , and the image display apparatus  64 . The image signal generation circuit  62  generates an image signal corresponding to each pixel of the image display apparatus  64  from the image information. The generated image signal is inputted in the driving circuit  63 . The driving circuit  63  controls a voltage to be applied to the image display apparatus  64  on the basis of the inputted image signal and displays an image on a screen of the image display apparatus 
     Further, the present invention is not limited to the above-described embodiment and each constituent element may be substituted with a substitute and an equivalent if it achieves the object of the present invention. 
     First Embodiment 
       FIG. 7I  shows a schematic plan view of an electron source that is manufactured according to the present embodiment.  FIG. 8  shows a schematic cross section in a lateral direction of a slit-like opening of an electron-emitting device according to the present embodiment.  FIGS. 7A to 7J  show a manufacturing method of the electron source according to the present embodiment. Hereinafter, a manufacturing step of the electron source according to the present embodiment will be described in detail. 
     (Step 1) 
     At first, on a quartz substrate  71 , of which surface is sufficiently cleaned, Cu having a thickness 3 μm and a width 50 μm is formed as a signal wiring  72  by a printing method ( FIG. 7A ). 
     (Step 2) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and on the side of the signal wiring  72 , a slit-like amorphous carbon film having a thickness 30 nm is formed as an electron-emitting film  73  ( FIG. 7B ). The electron-emitting film  73  is formed by using a plasma CVD method. 
     The width of the slit-like electron-emitting film  73  (in the lateral direction) is defined to be 5 μm and the length thereof (in the longitudinal direction) is defined to be 85 μm. 
     (Step 3) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and a mixed film composed of SiOxNy (x=1 to 2, y=0 to 1) and Al, having a thickness 100 nm, is formed as a resistance layer  74  so as to cover the electron-emitting film  73  ( FIG. 7C ). The resistance layer  74  is formed by using a co-spatter method. 
     (Step 4) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and TiN having a thickness 100 nm is formed by spattering as a convergent and cathode electrode  75 . The convergent and cathode electrode  75  is formed so as to overlap with an area where a scanning wiring  79  is formed in Step 8 ( FIG. 7D ). 
     (Step 5) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and SiO 2  having a thickness 1 μm is formed as an insulating layer  76  on the area where the electron-emitting device is formed ( FIG. 7E ). The insulating layer  76  is formed by using a spatter method. 
     (Step 6) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and TiN having a thickness 100 nm is formed as a gate electrode  77  on the area where the electron-emitting device is formed and the area of the signal wiring  72  ( FIG. 7F ). The gate electrode  77  is formed by using a spatter method. 
     (Step 7) 
     Subsequently, using a mask, SiO 2  having a thickness 5 μm and a width 210 μm is formed as an insulating layer  78  having a contact hole  78   a  so as to contact a scanning wiring  79  to the convergent and cathode electrode  75  ( FIG. 7G ). The insulating layer  78  having the contact hole  78   a  is formed by using a printing technology. 
     (Step 8) 
     Subsequently, by using a mask, Ag having a thickness 13 μm and a width 200 μm is formed as the scanning wiring  79  is formed on the insulating layer  78  ( FIG. 7H ). The scanning wiring  79  is formed by using a printing method. 
     By providing the contact hole  78   a  formed in Step 7, the scanning wiring  79  is allowed to electrically contact the convergent and cathode electrode  75 . 
     (Step 9) 
     Finally, a pattern for lift-off is formed by a photoresist, and a rectangular opening is formed as a slit-like opening  80  on the area where the electron-emitting device is formed ( FIG. 7I ). The slit-like opening  80  is formed by using an etching technology. Through the above-described steps, the electron source according to the present embodiment is completed. The slit-like opening  80  is formed so that the extended line in the longitudinal direction of the slit-like opening  80  is at a right angle to the scanning wiring  79 . 
     Etching in Step 9 is carried out so that the electron-emitting film  73  is exposed. The gate electrode  77  is etched by dry etching using BCl 3 . The insulating layer  76  is etched by dry etching using CF 4 . The convergent and cathode electrode  75  is etched by dry etching using BCl 3 . Then, the resistance layer  74  is etched by wet etching using BHF. Due to these etching, the surface of the electron-emitting film  73  is exposed. Due to wet etching by BHF, the insulating layer  76  is also etched a little. 
     According to the present embodiment, by disposing the resistance layer  74  between the electron-emitting film  73  and the convergent and cathode electrode  75 , as compared to an electron-emitting device with a focusing electrode and a cathode electrode electrically connected like the electron-emitting device shown in  FIG. 2  (namely, an electron-emitting device such that the potential of the focusing electrode is equal to the potential of the cathode electrode), fluctuation of emission of electrons can be reduced. 
     In the electron-emitting device according to the present embodiment, when the electron is injected in the electron-emitting film  73 , the electron necessarily passes through the resistance layer  74 . Therefore, in accordance with change of the current amount flowing through the resistance layer  74 , a voltage drop generated in the resistance layer  74  is changed. If the voltage drop is changed, a potential difference is generated between the convergent and cathode electrode  75  and the electron-emitting film  73 . As a result, an intensity of an electric field to be applied to the electron-emitting film  73  is changed, so that the current amount to be emitted from the electron-emitting film  73  is also changed. 
     Specifically, if the electron is emitted from the electron-emitting film  73 , in accordance with the current amount, the voltage drop occurs in the resistance layer  74 , so that the potential of the electron-emitting film  73  is slightly higher than that of the convergent and cathode electrode  75 . If current amount to be emitted from the electron-emitting film  73  is increased, a potential difference between the convergent and cathode electrode  75  and the electron-emitting film  73  is increased, so that an intensity of an electric field to be applied to the electron-emitting film  73  is weakened. As a result, the current amount to be emitted from the electron-emitting film  73  is reduced. On the other hand, if the current amount to be emitted from the electron-emitting film  73  is reduced, a potential difference between the convergent and cathode electrode  75  and the electron-emitting film  73  is decreased, so that an intensity of an electric field to be applied to the electron-emitting film  73  is intensified. As a result, the current amount to be emitted from the electron-emitting film  73  is increased. Due to occurring of such a phenomenon, according to the electron-emitting device of the present embodiment, it is possible to stabilize the current amount to be emitted from the electron-emitting film  73  and to reduce fluctuation of emission of electrons. 
     In addition, in the electron source of the present embodiment, since the electron-emitting material portion is separated for each slit-like opening  80  ( FIG. 7B ), the current amount to be injected passing through the resistance layer  74  formed thereon is limited for each slit-like opening  80 . As a result, dispersion in fluctuation of emission of electrons between the slit-like openings  80  is reduced. 
     In addition, since the electron source according to the present embodiment is provided with the resistance layer  74  for each electron source ( FIG. 7C ), in the case that a plurality of electron sources according to the present embodiment is arranged in a matrix, dispersion in fluctuation of emission of electrons between respective electron sources is reduced so as to be capable of providing a beautiful image. 
     A spacer  81  having a thickness 1.6 mm and a width 200 μm is arranged on the scanning wiring  79  of the electron source according to the present embodiment ( FIG. 7J ). Further, an FP having the phosphor arranged is arranged thereon, and the electron beam emitted from the electron source is observed. A schematic view of a configuration for driving the electron source is shown in  FIG. 9 . A voltage Va=10 kV is applied to an FP  91  and a voltage Vg=20V is applied to the gate electrode  77 , and the electron beam is observed. For comparison, an electron source such that a shape of an opening and a distance from the spacer to the opening are the same as those of the electron source according to the present embodiment and the extended line in a longitudinal direction of the slit-like opening is in substantially parallel with the scanning wiring (the extended line does not intersect with the scanning wiring) is also manufactured. Comparing the electron source according to the present embodiment with the electron source according to a comparison example, deviation of a position of the electron beam in the electron source according to the present embodiment is largely improved as compared to the comparison example. 
     Second Embodiment 
       FIG. 10I  shows a schematic plan view of an electron source that is manufactured according to the present embodiment.  FIG. 11  shows a schematic cross section in a longitudinal direction of a slit-like opening of an electron-emitting device according to the present embodiment.  FIGS. 10A to 10J  show a manufacturing method of the electron source according to the present embodiment. Hereinafter, a manufacturing step of the electron source according to the present embodiment will be described in detail. The explanation about the parts overlapped with the first embodiment is herein omitted. 
     (Step 1) 
     At first, on a quartz substrate  101 , of which surface is sufficiently cleaned, Cu having a thickness 3 μm and a width 50 μm is formed by a printing method so as to form a signal wiring  102  ( FIG. 10A ). 
     (Step 2) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and on the side of the signal wiring  102 , TiN having a thickness 300 nm is formed as a cathode electrode  103  by a spatter method. On the cathode electrode  103 , a pattern for lift-off is formed by a photoresist, and as an electron-emitting film  104 , an amorphous carbon film having a thickness 30 nm is formed by a plasma CVD method ( FIG. 10B ). 
     (Step 3) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and SiO 2  having a thickness 100 nm is formed as an insulating layer  105  by a spatter method so as to cover the electron-emitting film  104  ( FIG. 10C ). 
     (Step 4) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and a mixed film composed of SiOxNy (x=1 to 2, y=0 to 1) and Al, having a thickness 100 nm, is formed as a resistance layer  106  so as to cover the cathode electrode  103  disposed on the portion that is not covered with the insulating layer  105  by using a co-spatter method ( FIG. 10D ). 
     (Step 5) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and TiN having a thickness 100 nm is formed by a spatter method as a focusing electrode  107 . The focusing electrode  107  is formed so as to be overlapped with the area where a scanning wiring  111  is formed in Step 8 ( FIG. 10E ) 
     (Step 6) 
     Subsequently, a pattern for lift-off is formed by a photoresist, and SiO 2  having a thickness 1 μm is formed as an insulating layer  108  by a spatter method on the area where the electron-emitting device is formed. Then, a pattern for lift-off is formed by a photoresist, and TiN having a thickness 100 nm is formed by a spatter method as a gate electrode  109  on the area where the electron-emitting device is formed and the area of the signal wiring  102  ( FIG. 10F ). 
     (Step 7) 
     Subsequently, by using a mask, SiO 2  having a thickness 5 μm and a width 210 μm is formed as an insulating layer  110  by a printing technology as an insulating layer  110  having a contact hole  110   a  so as to contact a scanning wiring  111  and the focusing electrode  107  ( FIG. 10G ). 
     (Step 8) 
     Subsequently, by using a mask, Ag having a thickness 13 μm and a width  200  pin is formed as the scanning wiring  111  by a printing technology on the insulating layer  110  ( FIG. 10H ). By providing the contact hole  110   a  of the insulating layer  110  that is formed in Step 7, the scanning wiring  111  is allowed to electrically contact the focusing electrode  107 . 
     (Step 9) 
     Finally, a pattern for lift-off is formed by a photoresist, and a rectangular opening is formed as a slit-like opening  112  on the area where the electron-emitting device is formed by an etching technology ( FIG. 10I ). Through the above-described steps, an electron source according to the present embodiment is completed. The slit-like opening  112  is formed so that the extended line in the longitudinal direction of the slit-like opening  112  is at a right angle to the scanning wiring  111 . The method of etching is the same as the first embodiment. 
     According to the present embodiment, by disposing the resistance layer  106  between the focusing electrode  107  and the cathode electrode  103 , all of the electrons to be provided to the electron-emitting film  104  will be routed through the resistance layer  106 . As a result, according to the present embodiment, due to the resistance layer  106  disposed between the focusing electrode  107  and the cathode electrode  103 , the same effect as the first embodiment can be obtained so that fluctuation of emission of electrons can be reduced. 
     In addition, as same as the electron source as the first embodiment, since the electron source according to the present embodiment is provided with the resistance layer  106  for each electron source ( FIG. 10D ), in the case that a plurality of the electron sources according to the present embodiment is arranged in a matrix, dispersion in fluctuation of emission of electrons between respective electron sources is reduced so as to be capable of providing a beautiful image. 
     As same as the first embodiment, on the scanning wiring  111  of the electron source according to the present embodiment, a spacer  113  having a thickness 1.6 mm and a width 200 μm is arranged ( FIG. 10J ). Further, the FP having the phosphor arranged is arranged thereon, and the electron beam emitted from the electron source is observed. For comparison, an electron source such that a shape of an opening and a distance from the spacer to the opening are the same as those of the electron source according to the present embodiment and the extended line in a longitudinal direction of the slit-like opening is in substantially parallel with the scanning wiring (the extended line does not intersect with the scanning wiring) is also manufactured. Comparing the electron source according to the present embodiment with the electron source according to a comparison example, deviation of a position of the electron beam in the electron source according to the present embodiment is largely improved as compared to the comparison example. 
     Third Embodiment 
       FIG. 12I  shows a schematic plan view of an electron source that is manufactured according to the present embodiment.  FIG. 13  shows a schematic cross section in a longitudinal direction of a slit-like (a rectangular) opening of an electron-emitting device according to the present embodiment.  FIGS. 12A to 12J  show a manufacturing method of an electron source according to the present embodiment. The electron source according to the present embodiment is an example that a cathode electrode portion for supplying an electron to an electron-emitting film is defined as a resistance. Here, a characteristic part of the present embodiment is only described and the overlapped explanation is omitted. 
     According to the present embodiment, in Step 2 according to the second embodiment, in place of a step for forming a cathode electrode, as a cathode electrode and resistance  123 , a mixed film composed of SiOxNy (x=1 to 2, y=0 to 1) and Al, having a thickness 100 nm, is formed by a co-spatter method ( FIG. 12B ). In addition, Step 4 of the second embodiment is omitted. Since other steps are equal to the second embodiment, the explanation thereof is herein omitted. 
     According to the present embodiment, using the cathode electrode and resistance  123  as the cathode electrode, the cathode electrode and resistance  123  and the focusing electrode  107  are isolated via the insulating layer  105  in the vicinity of the electron-emitting portion. Thereby, according to the electron source of the present embodiment, the same effects as the first embodiment and the second embodiment can be obtained, so that fluctuation of emission of electrons can be reduced. 
     In addition, since the electron source according to the present embodiment is provided with the cathode electrode and resistance  123  for each electron source as same as the electron source according to the first and second embodiments ( FIG. 12B ), when a plurality of electron sources according to the present embodiment is arranged in a matrix, dispersion in fluctuation of emission of electrons among respective electron sources is reduced and a beautiful image can be provided. 
     As same as the second embodiment, the spacer  113  having a thickness 1.6 mm and a width 200 μm is arranged on the scanning wiring  111  according to the present embodiment ( FIG. 12J ). Further, the FP which the phosphor is arranged is arranged thereon, and the electron beam that is emitted from the electron source is observed. For comparison, an electron source such that a shape of an opening and a distance from the spacer to the opening are the same as those of the electron source according to the present embodiment and the extended line in a longitudinal direction of the slit-like opening is in substantially parallel with the scanning wiring (the extended line does not intersect with the scanning wiring) is also manufactured. Comparing the electron source according to the present embodiment with the electron source according to a comparison example, deviation of a position of the electron beam in the electron source according to the present embodiment is largely improved as compared to the comparison example. 
     Fourth Embodiment 
       FIG. 14  shows a schematic plan view of an electron source that is manufactured according to the present embodiment. The electron source according to the present embodiment is an example that the extended line in a longitudinal direction of the slit-like (a rectangular) opening  80  intersects with the scanning wiring not at a right angle but obliquely. Since the present embodiment is equal to the manufacturing method of the electron source according to the first embodiment, the overlapped explanation is herein omitted. 
     The electron source according to the present embodiment is arranged as same as the first embodiment as shown in  FIG. 9 , and the shape of the electron beam is observed. As same as the first embodiment, for comparison, an electron source such that a shape of an opening and a distance from the spacer to the opening are the same as those of the electron source according to the present embodiment and the extended line in a longitudinal direction of the slit-like opening is in substantially parallel with the scanning wiring (the extended line does not intersect with the scanning wiring) is also manufactured. Comparing the electron source according to the present embodiment with the electron source according to a comparison example, deviation of a position of the electron beam in the electron source according to the present embodiment is largely improved as compared to the comparison example. 
     Fifth Embodiment 
       FIG. 15  shows a schematic plan view of an electron source that is manufactured according to the present embodiment. The electron source according to the present embodiment is an example that the convergent and cathode electrode  75  is connected to the signal wiring  72  and the gate electrode  77  is connected to the scanning wiring  79  on the contrary to the above-described electron source. According to the manufacturing method of the electron source according to the present embodiment, the convergent and cathode electrode  75  is formed so as to be connected to the signal wiring  72  in Step 4 of the first embodiment, and the gate electrode  77  is formed so as to be connected to the scanning wiring  79  in Step 8 of the first embodiment. Other steps are equal to the step of the first embodiment, so that the overlapped explanation is herein omitted. 
     The electron source according to the present embodiment is arranged as same as the first embodiment as shown in  FIG. 9 , and the shape of the electron beam is observed. As same as the first embodiment, for comparison, an electron source such that a shape of an opening and a distance from the spacer to the opening are the same as those of the electron source according to the present embodiment and the extended line in a longitudinal direction of the slit-like opening is in substantially parallel with the scanning wiring (the extended line does not intersect with the scanning wiring) is also manufactured. Comparing the electron source according to the present embodiment with the electron source according to a comparison example, deviation of a position of the electron beam in the electron source according to the present embodiment is largely improved as compared to the comparison example. 
     Sixth Embodiment 
     The electron sources of the first to fifth embodiment is arranged in a matrix of 720×160, and an image display apparatus as shown in  FIG. 4  is manufactured. A plurality of electron sources is arranged at a pitch of 115 μm square and 345 μm high. A voltage of 10 kV is applied to the FP, and a voltage of 20 V is applied between the scanning wiring and the signal wiring. As a result, a high-definition image display apparatus which can be driven in a matrix can be formed. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.