JP3554216B2 - Image forming device - Google Patents

Description

を満たす接続長を採ることにより、上記した２次的な放電を抑えられることがわかった。
【００４２】
また接続長を一定にして導電膜４０２５のシート抵抗を変えて評価したところ、同様に上記式（１）を満たすシート抵抗の導電膜とすることにより２次放電が抑えられる。上記シート抵抗としては、好ましくは、１０Ω／□以下であり、さらには４Ω／□以下が好ましい。
【００５０】
さらに、導電膜４０２５は、画像領域の直ぐ近傍に位置する。このため、導電膜４０２５が、画像表示をした時に観察者側（大気側）から見える場合、コントラストが低下する場合があるので、導電膜４０２５を黒色に近づけるのが好ましい。具体的には、導電膜４０２５に黒色顔料を混合させる、あるいは導電膜層導電膜４０２５とガラス基板との間に黒色部材を配置することが挙げられる。この黒色部材としては、蛍光体間に配置する黒色部材（ブラックマトリクス、ブラックストライプ）を延長することにより対応できる。
【００５１】
【発明の実施の形態】
以下、実施例を挙げて本発明を説明する。
【００５２】
（実施例１）
本実施例の画像形成装置は、走査ライン数２４０本（ラインピッチ０．６５ｍｍ）、変調信号ライン数７２０本（２４０×ＲＧＢ、画素ピッチ０．２９×３ｍｍ）の画像形成装置である。図１０に外観を示した。画像表示領域（蛍光膜形成領域）は１５６×２０９ｍｍである。
【００５３】
次に、本実施例で形成した画像形成装置のフェースプレートの構成について説明する。図５に外観を示した。まず、蛍光面の作製工程について説明する。
【００５４】
図６（１）〜（７）に作製工程を示す。
【００５５】
（１）まず引き出し配線４０２１を透明基板上に印刷法により作製する。配線は銀ペーストによる配線でシート抵抗が０．１Ω／□以下となるように作製した。
【００５６】
（２）次に導電膜４０２５を同じく印刷法により作製した。導電膜４０２５はガラスペーストにカーボンを混合したものを用い、厚さ２μｍとなるように作製した。また、その表面の粗さを０．２μｍとした。また、導電膜４０２５のシート抵抗は５０Ω／□であった。導電膜４０２５の接続長Ｗは、前述した式（１）を充分満たすようにＷ＝１５０ｍｍとした。
【００５７】
（３）次に絶縁性のブラックストライプ４０２２を同じく印刷法により作製した。この厚さは３μｍとした。
【００５８】
（４）次にＲＧＢの蛍光体層４００８を同じく印刷法により作製した。用いた蛍光体はＰ２２系の蛍光体で、ＲＧＢ共に平均粒径５μｍのものを用いて、厚さ１５μｍの蛍光体層４００８とした。
【００５９】
（５）次にコロイダルシリカ、界面活性剤などを含んだ水溶液を蛍光面上に塗布し、まず蛍光体層４００８の凹凸部を湿潤させ、ついでポリメタクリレートを主成分とした樹脂を可塑剤とともにトルエン、キシレン等の非極性溶媒中に溶解させ、これを蛍光面上にスプレーし、蛍光体凹凸上にオイルオーバーウオーター型の小滴を載せ，スピンコートにより延伸させたのち、水分と溶剤成分を乾燥除去し厚さ３μｍのフィルミング膜４０２８を作製した。
【００６０】
（６）次に画像領域（蛍光膜形成領域）および導電膜の一部を覆う領域に開口を持ったアルミ蒸着用マスク４０２９を被せて、１０００Å厚のアルミをフィルミング膜４０２８上に蒸着した。
【００６１】
（７）最後に、この基板を焼成炉内で４５０℃まで１℃／ｍｉｎの昇温速度にて昇温させ、３０分この温度を維持したのち、−２．５℃／ｍｉｎの降温速度で冷却させ、樹脂中間層を熱分解除去した。フィルミング樹脂４０２８除去後にメタルバック層４００９は蛍光体層４００８、ブラックストライプ層４０２２、導電膜４０２５に覆い被さるようにして接触する。
【００６２】
このようにして作製したフェースプレートを用いて、電子源基板と３ｍｍ間隔となるようにスペーサ４０２０および支持枠４００７を配置して、図１０に示した画像形成装置を組み立てた。
【００６３】
ここで画像形成装置パネル内には、メタルバックに７ｋＶを印可した際に、メタルバックと電子源基板間で放電を開始するように、電子源基板側に電極を設けた（放電ギャップ形成）。尚この電極は高圧引き出し配線部から離れた画像領域内に作り込んだ。
【００６４】
比較例１として、用いた材料、作製法、接続長以外の寸法は本実施例と同一で、接続長Ｗを５ｍｍとした画像形成装置も作製した。やはりこの画像形成装置にも７ｋＶの放電ギャップを作り込んである。
【００６５】
これら２種の画像形成装置の高圧端子に７．５ｋＶの電位を印加して１分間放置する試験を行なった。比較例１のフェースプレートでは初期に放電ギャップの個所（放電ギャップを形成する電極とメタルバック間）で数回放電した後、その放電により導電膜４０２５に流れ込んだ大電流で、導電膜部分と電子源基板との間で激しく２次的な放電が起り、最後には導電膜４０２５が切断しメタルバックに高圧が印加されなくなってしまった。これに対し本実施例による画像形成装置は、放電ギャップの個所で１分間激しく放電が続くが、その放電電流を原因とする、比較例のような２次的な放電は見られなかった。
【００６６】
（実施例２）
次に別の実施例について説明する。本実施例では走査ライン数４８０本（ラインピッチ０．８５ｍｍ）、変調信号ライン数２４００本（８００×ＲＧＢ、画素ピッチ０．２９×３ｍｍ）の画像形成装置を作成した。
【００６７】
図７（１）にフェースプレートの外観を示した。画像表示領域は４０８×６９６ｍｍである。フェースプレートの製造プロセスは図６に示したものとは、導電膜４０２５と引き出し配線４０２１の作成順序が逆であること意外は、実施例１と同様に形成した。
【００６８】
図７（２）に、図７（１）のＦ−Ｆ‘断面に相当する部位での、本実施例の画像形成装置の部分断面図を示す。本実施例においては、導電膜４０２５は膜厚３μｍの黒色銀系配線でシート抵抗は０．５Ω／□である。導電膜４０２５とメタルバック４００９との接続長Ｗ２は式（１）を十分満たすように５ｍｍの長さを採っている。
【００６９】
高圧導入端子４０１１は直径２ｍｍのタングステンワイヤで、電子源基板４００４を貫通して、取り出し配線４０２１に押し当てて電気的接続をとっている。高圧引き出し線４０２１と導電膜４０２５との接続長Ｗ１は５．７ｍｍとし、式（１）を十分満たす。画像領域およびスペーサ４０２０から導電膜４０２５までの距離Ｌを１２ｍｍとした。
【００７０】
このフェースプレートを用いて、電子源基板とフェースプレートの間隔が２．５ｍｍの画像形成装置を組み立てた。フェースプレートには１０ｋＶの電位を印加したところ、充分な輝度を長時間に渡り安定に表示できた。本実施例の画像形成装置を前記式（４）を満たさないＶａを印可したところ放電と見られる現象が確認されたが、導電膜４０２５が蒸発したと思われる現象は生じなかった。
【００７１】
（実施例３）
次に別の実施例について説明する。本実施例で作成したフェースプレートの模式的平面図を図８（１）に示す。尚、図８（２）は、図８（１）のＧ−Ｇ‘での断面模式図である。本実施例では導電膜４０２５を白色銀配線で作製した。本実施例では導電膜４０２５とガラス基板との間に絶縁性ブラックストライプ４０２２を導電膜まで延長した（図８（２））。その他の構成は実施例１と同様にして画像形成装置を作成した。本実施例で作成した画像形成装置も放電などの現象も見られず、非常に明るく高輝度な画像が長時間安定に得られた。また、白色銀配線を用いても、画像表示面側からは黒色帯の縁取りしか見えず、画像への妨害感は感じられなかった。
【００７２】
導電膜材料として以上実施例で使用したもの以外に、酸化ルテニウムを含む導電膜も使用することができる。
【００７３】
【発明の効果】
以上説明したように、本発明によれば画像形成装置内で放電が発生しても、高圧取り出し配線とメタルバックの接続部分が焼失断線して高圧を印加できなくなることが無くなった。また画像領域端部やスペーサ部分で放電が発生しても、大量の導電性材料が電子源や配線、スペーサなどに蒸着されてダメージを受ける事が無くなった。
【図面の簡単な説明】
【図１】本発明のフェースプレートの模式図である。
【図２】本発明にかかわる高圧引き出し線とメタルバックを中継導電膜で接続する構造の代表例を示す図である。
【図３】メタルバックの密着度を抵抗値で評価するための評価系である。
【図４】放電が発生した際のダメージを受ける領域を示した模式図である。
【図５】本発明の第一の実施例で作成したフェースプレートを示す模式図である。
【図６】本発明の第一の実施例でのフェースプレートの作成工程を示す模式図である。
【図７】本発明の第二の実施例で作成したフェースプレートを示す模式図である。
【図８】本発明の第三の実施例で作成したフェースプレートを示す模式図である。
【図９】電子放出素子をマトリクス配置した電子源の構成を示す模式図である。
【図１０】図９の電子源を用いた画像形成装置の構造を示す模式図である。
【図１１】課題を示す模式図である。
【符号の説明】
４００１ 電子放出素子
４００２ 行方向配線
４００３ 列方向配線
４００４ 電子源基板
４００５ 支持部材
４００６ 透明（ガラス）基板
４００７ 支持枠
４００８ 蛍光膜
４００９ メタルバック
４０１０ 高圧電源
４０１１ 高圧導入線
４０１５ 銀ペースト
４０２０ 大気圧支持構造（スペーサ）
４０２１ 高圧引き出し配線
４０２２ 黒色部材
４０２３ メタルバックの断線部
４０２４ メタルバックが大きく火脹れしている個所
４０２５ 導電膜
４１００ 導電膜
４１０１ アルミ膜
４１０２ 抵抗計
４０２８ フィルミング膜
４０２９ パターンマスク[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a configuration of a face plate of an image forming apparatus, and more particularly, to a connection configuration of a high voltage connection wiring of a face plate and a metal back layer.
[0002]
[Prior art]
An image display device using a cathode ray tube, such as a CRT, has been actively studied for a larger screen. Accordingly, increasing the depth and weight of the cathode ray tube has become an important issue.
[0003]
In order to solve these problems, the present inventors have studied a multi-electron beam source in which a number of surface-conduction emission devices of various materials, manufacturing methods and structures are arranged, and an image display device using the multi-electron beam source. I went.
[0004]
The inventors have attempted to apply a multi-electron beam source by, for example, the electrical wiring method shown in FIG. That is, it is a multi-electron beam source in which a large number of surface conduction emission devices are arranged two-dimensionally and these devices are wired in a simple matrix as shown in the figure.
[0005]
In the figure, 4001 schematically shows a surface conduction electron-emitting device, 4002 shows a row direction wiring, and 4003 shows a column direction wiring. Note that, for convenience of illustration, the matrix is shown as a 6 × 6 matrix, but the size of the matrix is not limited to this, and elements sufficient to display a desired image are arranged and wired.
[0006]
FIG. 10 shows the structure of a cathode ray tube using this multi-electron beam source. An outer container bottom 4005 provided with a multi-electron beam source 4004, an outer container frame 4007, a phosphor layer 4008 and a metal back 4009 are provided. This is a structure including a face plate 4006 provided. Further, a high voltage is applied to a metal back 4009 on the transparent substrate 4006 constituting the face plate by a high voltage power supply 4010 through a high voltage introducing terminal 4011.
[0007]
In a multi-electron beam source in which the surface conduction electron-emitting devices are arranged in a simple matrix, an appropriate electric signal is applied to the row wiring 4002 and the column wiring 4003 in order to output a desired electron beam. For example, to drive a surface conduction electron-emitting device of an arbitrary row in a matrix, a selection voltage Vs is applied to a row-directional wiring 4002 of a selected row, and simultaneously, a row-directional wiring 4002 of an unselected row is applied. Applies a non-selection voltage Vns. In synchronization with this, a drive voltage Ve for outputting an electron beam is applied to the column wiring 4003. According to this method, a voltage of Ve-Vs is applied to the surface-conduction emission devices of the selected row, and a voltage of Ve-Vns is applied to the surface-conduction emission devices of the non-selected rows. If Ve, Vs, and Vns are set to appropriate voltages, electron beams of a desired intensity are output only from the surface conduction electron-emitting devices in the selected row, and a different drive voltage Ve is applied to each of the column wirings. When applied, electron beams of different intensities are output from each of the elements in the selected row. Further, since the response speed of the surface conduction electron-emitting device is high, if the length of time for applying the driving voltage Ve is changed, the length of time for outputting the electron beam can also be changed.
[0008]
The electron beam output from the multi-electron beam source 4004 by the voltage application as described above is applied to a metal back 4009 to which a high voltage is applied, and excites a phosphor 4008 as a target to emit light. Therefore, for example, by appropriately applying a voltage signal corresponding to image information, an image display device can be obtained.
[0009]
In this image display device, since the multi-electron beam source substrate and the face plate are opposed to each other, a thin and lightweight image display device can be realized. Further, by inserting a structure supporting the atmospheric pressure, that is, by inserting a spacer 4020 between the face plate and the electron source substrate, it is possible to increase the area while keeping the thickness low. It is highly expected as a tube.
[0010]
[Problems to be solved by the invention]
As the metal back 4009 on the transparent substrate 4006, a very thin film having a thickness of 500 to 3000 mm is formed on the filming resin, and then the filming resin is removed by baking, and the metal back layer 4009 and the underlayer (phosphor or face) are removed. (A plate). Since the metal back layer is formed in such a process, the metal back layer has many portions floating from the underlying layer, has a very low adhesion to the underlying layer, and has a brittle configuration due to its small thickness. Therefore, when the high-voltage introduction terminal is directly connected to the metal back layer, the reliability of the electrical connection is reduced. Therefore, a thick film (for example, 5 to 20 μm thick) made of a conductive paste containing metal particles such as Ag is used as the high-voltage extraction wiring. The connection was made via the wiring 4021. That is, as shown in FIG. 11A, the thick-film wiring 4021 and the high-voltage introduction terminal 4011 are securely connected with the silver paste 4015 or the like, and the metal back 4009 is formed so as to be in contact with the thick-film wiring 4021. .
[0011]
However, since the filming resin is formed thinner than the thick film wiring 4021 as shown in FIG. 11B by enlarging a portion C in FIG. 11A, the filming resin is thicker. The end of the film wiring 4021 could not be continuously covered, and as a result, the metal back 4009 formed on the filming resin did not become a continuous film. Therefore, disconnection 4023 may occur at the end of the thick film wiring 4021, and a connection failure between the thick film wiring 4021 and the metal back 4009 may occur.
[0012]
In addition, as shown in FIG. 11, when a metal back is formed on a glass substrate 4006 having a smooth surface, after the firing of the filming resin is finished, a large metal back portion is formed on the glass substrate. The wrinkles were swelled and the occurrence of 4024 was observed. Such a metal back wrinkle or swelling 4024 becomes a large floating state of 10 to 100 μm or more in a region on the order of millimeters, particularly when the base is high in flatness such as a glass substrate.
[0013]
Such expansion 4024 of the metal back may cause a discharge when a high voltage is applied between the metal back and the electron source substrate 4004.
[0014]
Furthermore, in some cases, the flat plate type image display device in which the electron source substrate and the face plate are brought into close proximity to each other and a high voltage is applied between them, an electrode on the face plate (a metal back or an anode electrode instead thereof) and an electron In some cases, discharge occurs between the substrate and a source substrate (members such as electron-emitting devices or wiring for driving each electron-emitting device). In some cases, such discharges occur on the surface of the atmospheric pressure supporting member (spacer portion).
[0015]
The current flowing on the face plate due to such discharge is several orders of magnitude larger than the current emitted from the electron-emitting device in normal image display.
[0016]
As described above, when a discharge occurs between the electron source substrate and the electrode on the face plate, a large current is concentrated on the high-voltage extraction wiring.
[0017]
At this time, if the connection portion between the high-voltage lead-out wiring and the metal back has a high resistance, heat is generated instantaneously in the portion during discharge, the gas adsorbed on the surface is released, and the degree of vacuum near the connection portion is reduced. Sometimes it got worse.
[0018]
When the above-described gas is released, a secondary discharge may be generated in the vicinity of the connection between the high-voltage lead-out wiring and the metal back. In such a case, the electrical connection between the high-voltage lead-out wiring and the metal back becomes insufficient, and as a result, it becomes impossible to apply a high voltage to the metal back, thereby making it impossible to display an image.
[0019]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a reliable image forming apparatus that can more reliably connect a metal back on a face plate of an image forming apparatus to a high-voltage lead-out wiring.
[0020]
[Means for Solving the Problems]
The present inventors have conducted intensive studies in order to solve the problems described above, and as a result, the following invention has been obtained.
[0021]
First, the first aspect of the present invention is to solve the problem that the metal back layer is disconnected at this end to cause a contact failure because a filming film cannot be continuously formed at the end of the high-voltage lead-out wiring. . That is, the first invention of the present invention resides in that a lead wiring and a metal back are connected via a conductive film 4025, as schematically shown in FIG. Note that FIG. 1B is a schematic diagram in which a connection portion between the extraction wiring 4021 and the metal back 4009 in FIG. 1A is enlarged.
[0022]
FIGS. 2A to 2C show specific examples in which the first lead wiring 4021 of the present invention and the metal back 4009 are connected via the conductive film 4025.
[0023]
First, FIG. 2A shows the simplest structure, in which a high-voltage lead wire 4021 and a phosphor layer 4008 are formed over a conductive film 4025. Normally, the step can be minimized by aligning the end of the conductive film with the end of the fluorescent film. However, since the phosphor layer 4008 is composed of a group of phosphor particles having a diameter of several μm. In addition, it is difficult to align the ends, and the manufacturing process becomes complicated.
[0024]
Therefore, here, the phosphor layer and the conductive film layer are arranged so as to partially overlap. According to this structure, a step is formed in the phosphor layer 4008 due to the conductive film 4025. However, by setting the thickness of the conductive film to 5 μm or less, more preferably 2 μm or less, filming for metal back film formation is performed. This step can be sufficiently covered without forming the resin thickly. Note that the thickness of the conductive film is preferably smaller than the thickness of the phosphor layer, and more preferably smaller than the average particle size of the phosphor particles constituting the phosphor layer.
[0025]
By doing so, the disconnection of the metal back caused by the absence of the filming film described above does not occur. On the other hand, the conductive film 4025 and the lead wiring 4021 are partially overlapped with each other in order to ensure electrical connection.
[0026]
Further, as shown in FIG. 2 (2) or (3), even when there is a black member (black stripe, black matrix) 4022 between the phosphors of the respective colors, a step formed at a portion where the conductive film and the black member overlap is still small. And filming resin.
[0027]
In FIG. 2B, conduction is achieved by partially covering the conductive film 4025 with the lead wiring 4021. In the case of FIG. 2 (2), the black member 4022 is partially covered with the conductive film. On the contrary, as shown in FIG. 2 (3), even if the black member partially covers the conductive film. good. In the case of the configuration shown in FIG. 2C, the metal back 4009 needs to extend beyond the black member 4022 and cover the conductive film 4025 to make an electrical connection.
[0028]
In addition, in the configuration of FIG. 2 (3), the conductive film partially covers the lead-out wiring, thereby making an electrical connection between the lead-out wiring and the conductive film. In this manner, the electrical connection may be ensured by covering the conductive film with the lead wiring. Further, the black member may be partially covered with a conductive film.
[0029]
Unlike the metal back, the conductive film 4025 is directly formed on the base (glass substrate) by printing or another film forming method. Therefore, as shown in FIG. Since the film can be formed thereon without disconnection, the vertical relationship and the thickness of the high-voltage lead-out wiring are not particularly limited as described above.
[0030]
Next, as described above, when the first configuration of the present invention is employed, the conductive film 4025 is covered with a metal back. At this time, if the surface of the conductive film 4025 is a smooth surface, the metal back on the conductive film 4025 may be expanded or wrinkled as in the case where the metal back is formed on the glass substrate. I will. When such an expansion or wrinkles occur, the reliability of the electrical connection between the metal back and the conductive film decreases.
[0031]
Therefore, a second aspect of the present invention is to provide a conductive film 4025 serving as a base for a metal back with a surface roughness Rz of 0.1 μm or more and a roughness of about 3 to 4 times or less the thickness of the filming resin.
[0032]
FIG. 3 is a schematic diagram showing a state of measurement performed to determine the surface roughness in the above-described range. Specifically, in the measurement of FIG. 3, the surface roughness of the conductive film 4100 was changed, and a metal back 4101 was formed thereon. The degree of floating of the metal back with respect to the conductive film was evaluated by measuring how much the contact resistance between the conductive film and the metal back changed when the surface roughness of the conductive film was changed with a resistance meter 4102. The definition of the surface roughness Rz is based on JIS-B601.
[0033]
In the case where the surface roughness of the conductive film 4100 corresponding to the base of the metal back 4101 is 0.1 μm or less, the formed metal back has a large floating and a high contact resistance or is very unstable.
[0034]
On the other hand, stable when the surface roughness Rz of the conductive film 4100 corresponding to the base of the metal back 4101 is 0.1 μm or more, more preferably 1 μm or more, and about 3 to 4 times or less the thickness of the filming resin. Contact was obtained.
[0035]
On the other hand, when the surface roughness of the conductive film 4100 corresponding to the base of the metal back 4101 is further large, a discontinuity occurs in the metal back due to a step due to the unevenness. However, unlike the case where the metal back is directly covered on the high-voltage lead-out wiring described above, since the steps are not linearly continuous, no disconnection occurs, but the contact resistance is slightly increased.
[0036]
From these results, it is desirable that the above-described conductive film serving as the base of the metal back has a surface roughness of 0.1 μm or more and a roughness of about 3 to 4 times or less the thickness of the filming resin. Got. The surface roughness Rz of the normally used phosphor layer and black member (black stripe) is in this range.
[0037]
Next, in the third aspect of the present invention, when a discharge occurs between the electron source substrate and the electrode (anode) on the face plate, heat is generated at a connection portion between the high-voltage extraction wiring and the metal back, and the high-voltage extraction is performed. In order to cope with a phenomenon that a secondary discharge occurs due to degassing from the vicinity of the wiring, a configuration is adopted in which the resistance of the connecting portion between the lead wiring and the conductive film or between the conductive film and the metal back is reduced.
[0038]
With such a configuration, heat generation in the high-voltage lead-out wiring portion is suppressed, and as a result, the above-described secondary discharge can be suppressed.
[0039]
Specifically, the third aspect of the present invention is to increase the connection length between the high-voltage lead-out wiring and the conductive film, or the connection length between the metal back and the conductive film, or to reduce the sheet resistance of the conductive film to reduce the connection resistance. It is to lower the resistance. Note that the connection length refers to the length of the end face of the conductive film or the lead-out wiring at the connection part between the conductive film and the lead-out wiring, as described in the connection part between the conductive film and the lead-out wiring.
[0040]
When the frequency of occurrence of secondary discharge was evaluated by changing the connection length, the connection length between the conductive film 4025 and the high-voltage lead-out wiring: W1 [mm] and the connection length between the conductive film 4025 and the metal back: W2 [ mm] with respect to the sheet resistance r [Ω / □] of the conductive film 4025.
[Outside 4]

It has been found that the above secondary discharge can be suppressed by adopting a connection length satisfying the following.
[0042]
In addition, when the connection length was fixed and the sheet resistance of the conductive film 4025 was changed and evaluated, a secondary discharge is similarly suppressed by using a conductive film having a sheet resistance that satisfies the above equation (1). The sheet resistance is preferably 10Ω / □ or less, and more preferably 4Ω / □ or less.
[0050]
Further, the conductive film 4025 is located immediately near the image area. For this reason, when the conductive film 4025 is viewed from the observer side (atmosphere side) when an image is displayed, the contrast may be reduced. Therefore, it is preferable to make the conductive film 4025 close to black. Specifically, a black pigment is mixed in the conductive film 4025, or a black member is provided between the conductive film 4025 and the glass substrate. This black member can be dealt with by extending a black member (black matrix, black stripe) disposed between the phosphors.
[0051]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to examples.
[0052]
(Example 1)
The image forming apparatus of this embodiment is an image forming apparatus having 240 scanning lines (0.65 mm line pitch) and 720 modulation signal lines (240 × RGB, pixel pitch 0.29 × 3 mm). FIG. 10 shows the appearance. The image display area (the fluorescent film forming area) is 156 × 209 mm.
[0053]
Next, the configuration of the face plate of the image forming apparatus formed in this embodiment will be described. FIG. 5 shows the appearance. First, a manufacturing process of the phosphor screen will be described.
[0054]
6 (1) to 6 (7) show the manufacturing steps.
[0055]
(1) First, a lead wiring 4021 is formed on a transparent substrate by a printing method. The wiring was made of silver paste and was manufactured so that the sheet resistance was 0.1 Ω / □ or less.
[0056]
(2) Next, a conductive film 4025 was produced by the same printing method. The conductive film 4025 was formed using a mixture of glass paste and carbon and was formed to have a thickness of 2 μm. The surface roughness was set to 0.2 μm. The sheet resistance of the conductive film 4025 was 50 Ω / □. The connection length W of the conductive film 4025 was set to 150 mm so as to sufficiently satisfy the above-described expression (1).
[0057]
(3) Next, an insulating black stripe 4022 was produced by the same printing method. This thickness was 3 μm.
[0058]
(4) Next, an RGB phosphor layer 4008 was produced by the same printing method. The phosphor used was a P22-based phosphor having an average particle diameter of 5 μm for both RGB and a phosphor layer 4008 having a thickness of 15 μm.
[0059]
(5) Next, an aqueous solution containing colloidal silica, a surfactant and the like is applied on the phosphor screen, firstly, the uneven portion of the phosphor layer 4008 is wetted, and then a resin containing polymethacrylate as a main component together with a plasticizer is dissolved in toluene. , Dissolved in a non-polar solvent such as xylene, sprayed on the phosphor screen, placed oil-overwater type droplets on the phosphor irregularities, stretched by spin coating, and dried the water and solvent components The film was removed to form a filming film 4028 having a thickness of 3 μm.
[0060]
(6) Next, an aluminum evaporation mask 4029 having an opening was placed over an area covering an image area (a fluorescent film forming area) and a part of the conductive film, and aluminum having a thickness of 1000 mm was evaporated on the filming film 4028.
[0061]
(7) Finally, the temperature of the substrate is raised to 450 ° C. in a firing furnace at a rate of 1 ° C./min, and after maintaining the temperature for 30 minutes, the temperature is reduced at a rate of −2.5 ° C./min. After cooling, the resin intermediate layer was thermally decomposed and removed. After the removal of the filming resin 4028, the metal back layer 4009 comes into contact with the phosphor layer 4008, the black stripe layer 4022, and the conductive film 4025 so as to cover them.
[0062]
Using the face plate manufactured as described above, the spacer 4020 and the support frame 4007 were arranged at a distance of 3 mm from the electron source substrate, and the image forming apparatus shown in FIG. 10 was assembled.
[0063]
Here, in the image forming apparatus panel, an electrode was provided on the electron source substrate side (discharge gap formation) so as to start a discharge between the metal back and the electron source substrate when 7 kV was applied to the metal back. Note that this electrode was formed in an image area apart from the high-voltage lead-out wiring section.
[0064]
As Comparative Example 1, an image forming apparatus having the same dimensions as the present embodiment except for the materials used, the manufacturing method, and the connection length was used, and the connection length W was 5 mm. Again, this image forming apparatus has a discharge gap of 7 kV.
[0065]
A test was conducted in which a potential of 7.5 kV was applied to the high voltage terminals of these two types of image forming apparatuses and left for 1 minute. In the face plate of Comparative Example 1, after several discharges were initially made at the discharge gap (between the electrode forming the discharge gap and the metal back), a large current flowed into the conductive film 4025 by the discharge, and the conductive film portion and the electrons were discharged. Secondary discharge occurred violently with the source substrate, and finally the conductive film 4025 was cut and high voltage was not applied to the metal back. On the other hand, in the image forming apparatus according to the present embodiment, the discharge continued violently for one minute at the location of the discharge gap, but no secondary discharge caused by the discharge current as in the comparative example was observed.
[0066]
(Example 2)
Next, another embodiment will be described. In the present embodiment, an image forming apparatus having 480 scanning lines (0.85 mm line pitch) and 2400 modulation signal lines (800 × RGB, pixel pitch 0.29 × 3 mm) was prepared.
[0067]
FIG. 7A shows the appearance of the face plate. The image display area is 408 × 696 mm. The manufacturing process of the face plate was the same as that of Example 1 except that the order of forming the conductive film 4025 and the lead wiring 4021 was reversed from that shown in FIG.
[0068]
FIG. 7B is a partial cross-sectional view of the image forming apparatus of the present embodiment at a portion corresponding to the FF ′ cross section of FIG. 7A. In this embodiment, the conductive film 4025 is a black silver-based wiring having a thickness of 3 μm and a sheet resistance of 0.5Ω / □. The connection length W2 between the conductive film 4025 and the metal back 4009 has a length of 5 mm so as to sufficiently satisfy Expression (1).
[0069]
The high-voltage introduction terminal 4011 is a tungsten wire having a diameter of 2 mm, penetrates through the electron source substrate 4004, and is pressed against the extraction wiring 4021 to make electrical connection. The connection length W1 between the high-voltage lead wire 4021 and the conductive film 4025 is 5.7 mm, which satisfies the expression (1) sufficiently. The distance L from the image area and the spacer 4020 to the conductive film 4025 was set to 12 mm.
[0070]
Using this face plate, an image forming apparatus in which the distance between the electron source substrate and the face plate was 2.5 mm was assembled. When a potential of 10 kV was applied to the face plate, a sufficient luminance could be stably displayed for a long time. When the image forming apparatus of the present embodiment was applied with Va that did not satisfy the above formula (4), a phenomenon that was regarded as discharge was confirmed, but a phenomenon that seems to have vaporized the conductive film 4025 did not occur.
[0071]
(Example 3)
Next, another embodiment will be described. FIG. 8A shows a schematic plan view of the face plate created in this embodiment. FIG. 8B is a schematic sectional view taken along line GG ′ of FIG. 8A. In this embodiment, the conductive film 4025 was formed using white silver wiring. In this embodiment, an insulating black stripe 4022 is extended between the conductive film 4025 and the glass substrate to the conductive film (FIG. 8B). The other components were the same as those of the first embodiment to form an image forming apparatus. In the image forming apparatus prepared in this example, no phenomenon such as discharge was observed, and a very bright and high-luminance image was stably obtained for a long time. Further, even when the white silver wiring was used, only the black band border was visible from the image display surface side, and no disturbing feeling to the image was felt.
[0072]
As a conductive film material, a conductive film containing ruthenium oxide can be used in addition to those used in the above-described embodiments.
[0073]
【The invention's effect】
As described above, according to the present invention, even if a discharge occurs in the image forming apparatus, the connection portion between the high-voltage extraction wiring and the metal back is burned and disconnected, so that high voltage cannot be applied. Also, even if a discharge occurs at the end of the image area or at the spacer, a large amount of conductive material is not deposited on the electron source, the wiring, the spacer, and the like, thereby preventing damage.
[Brief description of the drawings]
FIG. 1 is a schematic view of a face plate of the present invention.
FIG. 2 is a view showing a typical example of a structure according to the present invention in which a high-voltage lead wire and a metal back are connected by a relay conductive film.
FIG. 3 is an evaluation system for evaluating the degree of adhesion of a metal back by a resistance value.
FIG. 4 is a schematic diagram showing a region that is damaged when a discharge occurs.
FIG. 5 is a schematic diagram showing a face plate created in the first embodiment of the present invention.
FIG. 6 is a schematic view showing a step of forming a face plate according to the first embodiment of the present invention.
FIG. 7 is a schematic diagram showing a face plate created in a second embodiment of the present invention.
FIG. 8 is a schematic view showing a face plate created in a third embodiment of the present invention.
FIG. 9 is a schematic diagram showing a configuration of an electron source in which electron-emitting devices are arranged in a matrix.
FIG. 10 is a schematic diagram showing a structure of an image forming apparatus using the electron source of FIG.
FIG. 11 is a schematic diagram showing a problem.
[Explanation of symbols]
4001 electron emission element 4002 row direction wiring 4003 column direction wiring 4004 electron source substrate 4005 support member 4006 transparent (glass) substrate 4007 support frame 4008 fluorescent film 4009 metal back 4010 high voltage power supply 4011 high voltage introduction line 4015 silver paste 4020 atmospheric pressure support structure ( Spacer)
4021 High voltage lead-out wiring 4022 Black member 4023 Disconnection portion of metal back 4024 Location where metal back is greatly expanded 4025 Conductive film 4100 Conductive film 4101 Aluminum film 4102 Resistance meter 4028 Filming film 4029 Pattern mask

Claims (8)

An electron source substrate including a plurality of electron-emitting devices disposed on a substrate, a phosphor layer disposed on a transparent substrate disposed to face the electron-emitting devices, a metal back layer covering the phosphor layer, and A face plate provided with a wiring for connecting the metal back layer to a power supply, wherein the wiring and the metal back layer are connected via a conductive film, and a connection length W1 between the conductive film and the wiring is provided. [Mm], and the connection length W2 [mm] between the conductive film and the metal back, with respect to the sheet resistance r [Ω / □] of the conductive film.

An image forming apparatus characterized by satisfying the following. The image forming apparatus according to claim 1, wherein the conductive film has a thickness of 5 μm or less. The image forming apparatus according to claim 2, wherein the conductive film has a thickness of 2 μm or less. 4. The image forming apparatus according to claim 1, wherein the surface roughness Rz of the conductive film is 0.1 μm or more. The image forming apparatus according to claim 4, wherein the conductive film has a surface roughness Rz of 1 μm or more. The image forming apparatus according to claim 1, wherein the metal back layer covers at least a part of the conductive film. The image forming apparatus according to claim 1, wherein the conductive film has a sheet resistance of 10 [Ω / □] or less. The image forming apparatus according to claim 7, wherein the conductive film has a sheet resistance of 4 [Ω / □] or less.

Images