JP2008166048A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device capable of suppressing discharge caused by a potential rise of a spacer. <P>SOLUTION: The image display device includes a front substrate 2 having a high voltage region 20 including a common electrode 33 formed in a periphery, a ground region 50 having a ground electrode 51 for surrounding the high voltage region 20, and a gap 40 formed between the high voltage region 20 and the ground region 50. A spacer 8 with lower electrical resistance than at least the gap 40 is arranged and extended so as to cross the gap 40 from the high voltage region 20 to the ground region 50 between the front substrate 2 and a back substrate 4. A track electrode 52 electrically connected to the spacer 8 is arranged in the ground region 50. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image display apparatus that displays an image by emitting electrons from an electron-emitting device provided on a back substrate and exciting and emitting a phosphor layer provided on the front substrate.

  In recent years, a liquid crystal display, a field emission display (FED), a plasma display (PDP), etc. are known as a display device having a vacuum envelope having a flat flat panel structure. In addition, as one type of FED, development of a display device (SED) including a surface conduction electron-emitting device is underway.

  The SED has a front substrate and a rear substrate that are arranged to face each other with a predetermined gap. These substrates are joined to each other at peripheral edges via rectangular frame-shaped side walls, and the inside is evacuated to form a flat envelope having a flat panel structure.

  On the inner surface of the front substrate, a phosphor screen having a metal back is formed on the phosphor layer of three colors, and on the inner surface of the rear substrate, a large number of electron-emitting devices that emit electrons that excite the phosphor layer are aligned. Has been placed. On the inner surface of the rear substrate, a large number of wirings for driving the electron-emitting devices are provided in a matrix, and the end portions are drawn out of the vacuum envelope.

  A plurality of plate-like spacers are provided between the front substrate and the rear substrate. These spacers function to support the atmospheric pressure load and maintain a gap between the substrates by contacting the inner surfaces of the front substrate and the rear substrate.

  When operating the SED configured as described above, an anode voltage is applied to the metal back to apply a high voltage of about 10 kV between the substrates, and each electron-emitting device is selectively driven via a drive circuit connected to the wiring. Apply voltage. Thereby, an electron beam is selectively emitted from each electron-emitting device, and the corresponding phosphor layer is irradiated with the electron beam, and the phosphor layer is excited and emitted to display a color image. .

  In the SED having the above structure, since an anode voltage of about 10 kV is applied between the front substrate and the back substrate facing each other through a minute gap of about 1 to 2 mm, a problem of discharge often occurs between the substrates. When a discharge is generated between the substrates, an electric charge charged on the entire surface of the metal back is concentrated on the discharge portion, and an excessive discharge current flows.

For this reason, conventionally, a metal back soft flash structure is known in which the metal back is divided into a plurality of strip-like elongated regions to reduce charge concentration due to discharge and to reduce damage due to discharge (Patent Document 1). .
JP 2006-185701 A

  In the display device having the above-described configuration, a gap portion having a high resistance film is formed between the high voltage region to which the anode voltage of the front substrate is applied and the grounded ground region, and a spacer is provided in the gap portion. There may be a crossing configuration. If the spacer has a lower resistance than the high resistance film in the gap portion, the current concentrates on the spacer. In addition, when an electron emission point is generated at the contact portion between the spacer and the substrate, the current concentration is further increased. In particular, when a high-resistance material is used for the grounding region, the voltage at the current concentration portion increases, and there is a possibility that electric discharge will occur due to electric field concentration.

  Patent Document 1 discloses a configuration for avoiding discharge damage in a high voltage region where an image is formed. However, there is no disclosure of a method for avoiding the discharge damage due to the increase in the potential of the ground region due to the current flowing through the spacer provided so as to cross the gap portion between the high voltage region and the ground region.

  Accordingly, an object of the present invention is to provide an image display device capable of suppressing discharge in the above configuration.

  In order to achieve the above object, an image display device of the present invention has a plurality of phosphor layers, a common electrode for applying a voltage is formed around the high voltage region for forming an image, and a ground surrounding the high voltage region. A front substrate having a ground region having electrodes, a gap formed between the high voltage region and the ground region, a rear substrate having a plurality of electron-emitting devices corresponding to a plurality of phosphor layers, and a front substrate; In order to maintain a distance from the rear substrate, a spacer having an electrical resistance lower than that of the gap is disposed between the front substrate and the rear substrate so as to extend across the gap from the high voltage region to the ground region. In a display device having a vacuum envelope in which the peripheral portions of the front substrate and the rear substrate disposed opposite to each other are sealed to make a vacuum inside, the spacer is electrically connected to the spacer in the ground region Having an electrode part The features.

  In the image display device of the present invention configured as described above, since the spacer is electrically connected to the electrode portion, an increase in the potential of the grounding region can be suppressed even when a current flows through the spacer.

  Moreover, the electrode part of the image display apparatus of this invention may be formed along the gap.

  Further, the spacer and the electrode portion may be electrically connected via a first resistance material.

  Further, the first resistance material may be a film-like member formed so as to cover the electrode portion.

  Moreover, the electrode part may be partially divided, and the spacer may be disposed in the divided part. In this case, it is possible to increase the degree of freedom in the layout arrangement of the spacers and electrode portions.

  Further, the spacer and the electrode portion may be electrically connected via a first resistance material and a second resistance material provided in the divided portion.

  Moreover, the electrode part and the ground electrode may be directly electrically connected. In this case, since the current from the spacer easily flows to the ground electrode, the potential increase can be more reliably suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the image display apparatus which can suppress discharge can be provided.

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

  First, referring to FIGS. 1 to 3, an SED (Surface-Conduction Electron-Emitter Display) will be described as an example of an image display device according to an embodiment of the present invention. FIG. 1 is a perspective view showing an SED vacuum envelope 10 (hereinafter also referred to as a display panel 10) in a state where a front substrate 2 is partially cut away. 2 is a cross-sectional view of the vacuum envelope 10 of FIG. 1 taken along line II-II. FIG. 3 is a partially enlarged sectional view in which the section of FIG. 2 is partially enlarged.

  As shown in FIGS. 1 to 3, the display panel 10 includes a front substrate 2 and a rear substrate 4 each made of a rectangular glass plate, and these substrates are separated from each other with a gap of about 1.0 to 2.0 mm. Opposed in parallel. The back substrate 4 has a size that is slightly larger than the front substrate 2. Further, the front substrate 2 and the rear substrate 4 are joined to each other through a rectangular frame-shaped side wall 6 made of glass, and constitute a vacuum envelope having a flat flat panel structure with a vacuum inside.

  A phosphor screen (image forming region) 12 that functions as an image display surface is formed on the inner surface of the front substrate 2. The phosphor screen 12 is configured by arranging red, blue, and green phosphor layers R, G, and B and a light shielding layer 11 and has a metal back 14 made of aluminum or the like. The phosphor layers R, G, B are formed in stripes or dots.

  On the inner surface of the back substrate 4, a number of surface-conduction electron-emitting devices 16 that emit electron beams for exciting and emitting the phosphor layers R, G, and B of the phosphor screen 12 are provided. These electron-emitting devices 16 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel, that is, for each of the phosphor layers R, G, and B. Each electron-emitting device 16 includes an electron emitting portion (not shown) and a pair of device electrodes for applying a voltage to the electron emitting portion. Further, on the inner surface of the back substrate 4, a large number of wirings 18 for applying a driving voltage to the respective electron-emitting devices 16 are provided in a matrix shape, and end portions thereof are drawn out of the vacuum envelope 10. Yes.

  The side wall 6 functioning as a bonding member is sealed to the peripheral edge of the front substrate 2 and the peripheral edge of the back substrate 4 by, for example, a sealing material 19 such as low melting glass or low melting metal, and these substrates are bonded to each other. is doing. In this embodiment, the back substrate 4 and the side wall 6 are bonded using frit glass 19a, and the front substrate 2 and the side wall 6 are bonded using indium 19b.

  Further, the display panel 10 includes a plurality of elongated plate-like spacers 8 between the front substrate 2 and the rear substrate 4 in order to maintain a distance between the front substrate 2 and the rear substrate 4. As will be described later, the spacer 8 extends from the high pressure region 20 to the grounding region 50 so as to straddle the gap 40 while being in contact with the gap 40 (see FIG. 4).

  Each spacer 8 abuts on the upper end 8 a that abuts on the inner surface of the front substrate 2 via the metal back 14 and the light shielding layer 11 of the phosphor screen 12 and the wiring 18 provided on the inner surface of the rear substrate 4. It has a lower end 8b. The plurality of spacers 8 support an atmospheric pressure load acting from the outside of the front substrate 2 and the rear substrate 4 and maintain the distance between the substrates at a predetermined value.

  The spacer 8 is preferably flat and formed from a material such as glass or ceramics. The present invention can be preferably applied regardless of whether the spacer 8 is insulating or conductive. However, when applying a high potential of several kV or more to the metal back 14, it is necessary that at least the spacer has conductivity. As such a conductive spacer, a spacer in which an insulating base material is coated with a conductive film, or a spacer that is conductive (not only the surface but also the inside) can be used. . However, if the spacer has high conductivity, there is a problem that power consumption as an image forming apparatus increases. Therefore, the spacer has a resistance that allows a minute current to flow between the conductive member (image forming member) on the face plate and the conductive member (wiring included in the electron source region) on the rear plate. preferable.

  Further, the SED includes a voltage supply unit (not shown) that applies an anode voltage to the metal back 14 of the front substrate 2. For example, the voltage supply unit increases the potential of the phosphor screen 12 by applying a high voltage of about 10 kV to the metal back 14. As a result, a potential difference of about 10 kV is formed between the grounded back substrate 4 and front substrate 2.

  When an image is displayed on the SED, a voltage is applied between the element electrodes of the electron-emitting device 16 via a drive circuit (not shown) connected to the wiring 18, and an electron beam is emitted from the electron-emitting portion of any electron-emitting device 16. And an anode voltage is applied to the metal back 14. The electron beam emitted from the electron emitting portion is accelerated by the anode voltage and is applied to the phosphor screen 12. As a result, the phosphor layers R, G, and B of the phosphor screen 12 are excited to emit light and display a color image.

  When manufacturing the display panel 10 having the above-described structure, the front substrate 2 provided with the phosphor screen 12 is prepared in advance, the electron-emitting devices 16 and the wirings 18 are provided, and the side walls 6 and the spacers 8 are joined. Prepared rear substrate 4 is prepared. Then, the front substrate 2 and the rear substrate 4 are arranged in a vacuum chamber (not shown), the inside of the vacuum chamber is evacuated, and then the front substrate 2 is bonded to the rear substrate 4 through the side wall 6.

  Next, FIG. 4 shows a schematic plan view of the front substrate (anode substrate) of the present embodiment. FIG. 5 shows an enlarged view of a portion A in FIG. In FIG. 4, the spacer is omitted.

  An image forming area 12 is formed in the high pressure area 20 of the front substrate 2. A common electrode 33 made of Ag is formed around the metal back 14 formed inside the surface of the image forming region 12.

  A ground electrode 51 and a track electrode 52 as an electrode portion are formed in the ground region 50 on the outer peripheral portion of the front substrate 2. The ground electrode 51 is formed on the outermost peripheral portion of the front substrate 2, and a low-resistance track electrode 52 is formed along the gap 40 to be described later.

  A gap 40 to which a high resistance film is applied is formed between the high voltage region 20 and the ground region 50. The common electrode 33 and the track electrode 52 are both printed on the film-like resistance material 60 and cover the common electrode 33 and the track electrode 52. As a result, it is possible to eliminate a portion where the metal is exposed in the ground region 50 serving as a cathode. The resistance member 60 and the ground electrode 51 are electrically connected.

  As shown in the enlarged view of part A in FIG. 5, the spacer 8 extends to a portion where the track electrode 52 is formed. The spacer 8 may have a lower resistance than the high resistance film in the gap 40, and in this case, the current flowing from the high voltage region 20 to the ground region 50 is concentrated on the spacer 8. In such a case, if the track electrode 52 is absent, the potential of the ground region 50 rises due to the resistance of the resistance material 60. As a result, electric field concentration occurs in the spacer 8 and there is a possibility of discharging. However, in this embodiment, the spacer 8 is electrically connected to the track electrode 52 via the resistance material 60. For this reason, the current flowing through the spacer 8 flows to the track electrode 52 through the resistance material 60, so that the potential increase of the spacer 8 can be suppressed and the occurrence of discharge due to potential concentration in the spacer 8 can be prevented. it can.

  FIG. 6 is an enlarged view of part A showing another configuration example of the track electrode. The track electrode 52 formed on the inner periphery of the ground electrode 51 in FIG. 5 is configured to be electrically connected to the ground electrode 51 via the resistance material 60. In contrast, in the configuration shown in FIG. 6, the track electrode 52 and the ground electrode 51 are electrically connected by the Ag electrode 53. As a result, the current from the spacer 8 is likely to flow not only to the track electrode 52 but also to the ground electrode 51, so that the potential increase of the spacer 8 can be more reliably suppressed. The Ag electrode 53 is preferably made of Ag as a material, but is not limited thereto. 5 illustrates a configuration in which the Ag electrode 53 is provided only at one place, but a plurality of Ag electrodes 53 may be provided.

  FIG. 7 is an enlarged view of a portion A showing still another configuration example of the track electrode.

  The track electrode 52 in the above-described example has a shape that surrounds the metal back 14 without a break. On the other hand, the track electrode 52a shown in the configuration example of FIG. 7 is divided at a portion where the spacer 8 extends. The divided distance is about 0.5 mm. A second resistance material 60b is formed in the divided portion. The second resistance member 60 b serves as a base of the spacer 8 and electrically connects the spacer 8 and the ground electrode 51. The spacer 8 is electrically connected to the track electrode 52a through the second resistance material 60b and the first resistance material 60a. Thus, although the track electrode 52a is divided, the spacer 8 is electrically connected to the track electrode 52a and the ground electrode 51 through the first resistance material 60a and the second resistance material 60b. For this reason, also in this structure, the effect of suppressing the electric potential rise of the spacer 8 and preventing discharge is acquired. And since this structure does not need to be a continuous track electrode without a cut | interruption, the freedom degree of the layout arrangement | positioning of the spacer 8 or the track electrode 52a can be raised.

  As described above, in the image display device according to the present embodiment, the low-resistance track electrode 52 is formed between the gap 40 formed around the high-voltage region 20 and the ground electrode 51, and the spacer 8 is formed on the track electrode 52. It has the structure extended to. With such a configuration, it is possible to suppress an increase in the potential of the ground region due to a current flowing through the spacer 8.

It is a perspective view which shows the vacuum envelope of SED of the state which notched the front substrate partially. It is sectional drawing which cut | disconnected the vacuum envelope of FIG. 1 by the line II-II. FIG. 3 is a partial enlarged cross-sectional view in which the cross section of FIG. 2 is partially enlarged. It is a typical top view of the front substrate of the present invention. It is an enlarged view of the A section of FIG. It is the A section enlarged view which shows the other structural example of a track electrode. It is the A section enlarged view showing other examples of composition of a track electrode.

Explanation of symbols

2 Front substrate 4 Back substrate 8 Spacer 20 High voltage region 33 Common electrode 40 Gap 50 Ground region 51 Ground electrode 52 Track electrode

Claims (7)

A high-voltage region having a plurality of phosphor layers and having a common electrode for applying a voltage formed therearound, a ground region having a ground electrode surrounding the high-voltage region, the high-voltage region, and the ground A front substrate with a gap formed between the regions;
A back substrate having a plurality of electron-emitting devices corresponding to the plurality of phosphor layers;
In order to maintain a gap between the front substrate and the back substrate, the front substrate and the back substrate are disposed so as to extend across the gap from the high-voltage region to the ground region. A spacer that is electrically lower in resistance than the gap;
In a display device having a vacuum envelope in which peripheral portions of the front substrate and the rear substrate disposed to face each other are sealed to make a vacuum inside,
An image display device having an electrode portion electrically connected to the spacer in the grounding region. The image display device according to claim 1, wherein the electrode portion is formed along the gap. The image display device according to claim 1, wherein the spacer and the electrode portion are electrically connected via a first resistance material. The image display device according to claim 3, wherein the first resistance material is a film-like member formed so as to cover the electrode portion. 5. The image display device according to claim 1, wherein a part of the electrode part is divided, and the spacer is arranged in the divided part. 6. The image display device according to claim 5, wherein the spacer and the electrode portion are electrically connected to each other via a first resistance material and a second resistance material provided in the divided portion. The image display device according to claim 1, wherein the electrode unit and the ground electrode are directly electrically connected.

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