JP4441457B2 - Image display device - Google Patents

Description

  The present invention relates to an image display apparatus in which an electrode plate is interposed between two substrates arranged opposite to each other.

  Conventionally, research on an image forming apparatus using an electron-emitting device has been advanced.

  For example, an electron source substrate on which a large number of cold cathode electron-emitting devices are formed, an anode electrode for accelerating electrons emitted from the electron-emitting devices, and an anode substrate equipped with a phosphor are opposed in parallel and evacuated to a vacuum. A flat-type electron beam display panel is known.

  A flat-type electron beam display panel can be reduced in weight and increased in screen size as compared with a cathode ray tube (CRT) display device that is widely used at present.

  In addition, flat-type electron beam display panels provide images with higher brightness and quality than other flat-panel display panels using liquid crystals, plasma displays, electroluminescence displays, etc. can do.

In Japanese Patent Laid-Open No. 2002-63859 (Patent Document 1), as an image display device in which an electrode plate is interposed between two opposed substrates, an electrode plate for controlling electrons emitted from an electron-emitting device is in a predetermined position. The image display device fixed to the is described. Specifically, an image display device in which an electrode plate for electronic correction is fixed with an adhesive to a step portion of a spacer having a step portion is described.
JP 2002-63859 A (paragraph 0044, FIG. 6)

  In the image display device described in Patent Document 1, when the adhesion by the adhesive is incomplete, the electrode plate is displaced. In addition, if the spacer and the electrode plate are firmly fixed with an adhesive, the spacer or the electrode plate is damaged during the heating process during the manufacture of the display device, and the spacer or the electrode plate is damaged. was there. This is considered due to the difference in the thermal expansion coefficient between the spacer and the electrode plate.

  It is an object of the present invention to provide an image display device that can solve the above-described problems and can easily fix an electrode plate at a predetermined position in the display device.

In order to achieve the above object, an image display device according to the present invention has a first substrate having a first conductor defined at a first potential and a second potential different from the first potential. A second substrate having a second conductor; an electrode plate disposed between the first substrate and the second substrate and defined at a third potential; and a narrow portion and a wide portion. An image display device having a spacer that penetrates the electrode plate at the narrow portion and locks the electrode plate at the wide portion to define a distance between the first substrate and the second substrate. The wide portion of the spacer is located between the first substrate and the electrode plate and satisfies the following relationship.
V1 / d1> V2 / d2
here,
V1: Potential difference between the first potential and the third potential
V2: Potential difference between the second potential and the third potential d1: Distance between the first substrate and the electrode plate d2: Distance between the second substrate and the electrode plate According to the above invention, the wide portion of the electrode plate The Coulomb attractive force acting between the substrate facing the side surface (first substrate) and the electrode plate is between the substrate facing the narrow side portion of the electrode plate (second substrate) and the electrode plate. Greater than the Coulomb attractive force acting between.

  For this reason, the electrode plate is applied to the step portion of the spacer (the boundary portion between the wide portion and the narrow portion) by the Coulomb attractive force that acts between the electrode plate and the substrate facing the wide portion side surface of the electrode plate. A predetermined position can be maintained by being held in contact.

  According to the present invention, since the spacer and the electrode plate are not fixed during the manufacturing process, specifically, during the heating process such as heating and cooling, it is caused by the difference in thermal expansion coefficient between the spacer and the electrode plate. The generation of stress can be prevented. Therefore, the risk of damaging the spacer and the electrode plate during the manufacturing process can be reduced.

  In addition, during operation of the display device, the electrode plate is pressed against and fixed to the wide portion of the spacer by the force of the electric field, so that the electrode plate can be easily positioned at a predetermined position with extremely high accuracy equivalent to the shape accuracy of the spacer. It becomes possible to fix to.

  The image display device of the present invention includes image display devices such as a liquid crystal display device, a plasma display device, and an electron beam display device (for example, a field emission display (FED)). The electron beam display device is a preferred form to which the present invention is applied in that it has an electron correction electrode that controls electrons emitted from the electron-emitting device toward the electron beam-excited phosphor layer. .

  Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, an electron beam display device (FED) is used as the image display device.

  FIG. 1A is a perspective view showing a schematic configuration of the image display apparatus of the present embodiment. FIG.1 (b) is the sectional view on the AA line of Fig.1 (a).

  In FIG. 1, the image display device includes a first substrate 1, a second substrate 2, an electrode plate 8, and a spacer 10.

  The first substrate 1 has a first conductor defined at a predetermined potential. The first substrate 1 is a substrate (rear plate) in which a plurality of electron-emitting devices 3 are formed in a matrix on a surface facing the second substrate 2, for example. In this case, the first conductor means an electron-emitting device.

  The second substrate 2 has a light emitting member 4 constituting an image display surface and a second conductor 5 defined at a specific potential different from the first conductor. Note that, when an electron beam display device is used as the image display device, the specific potential is preferably higher than a predetermined potential.

  The second substrate 2 is, for example, a face plate for an electron beam display device. The second substrate 2 is disposed so as to face the electron-emitting device 3. The light emitting member 4 is, for example, an electron beam excited phosphor layer, and is excited by the electrons emitted from the electron emitting element 3 to emit light, thereby displaying an image. The second conductor 5 is a thin film conductor that covers the light emitting member 4 and is, for example, a metal back made of Al.

  The electrode plate 8 is a grid, for example, and is disposed between the first substrate 1 and the second substrate 2. The electrode plate 8 controls the electron beam emitted from the electron-emitting device 3 toward the light emitting member 4. The electrode plate 8 has an opening 9 and a positioning hole 11. The electrode plate 8 is provided with the opening 9 so as to focus or correct the trajectory of electrons emitted from the electron-emitting device 3 toward the light-emitting member 4.

  The spacer 10 is interposed between the first substrate 1 and the second substrate 2 and defines an interval between the first substrate 1 and the second substrate 2. The spacer 10 includes a narrow portion 10a, a wide portion 10b, and a shoulder portion (step portion) 13 provided at the boundary between the narrow portion 10a and the wide portion 10b. The narrow width portion 10 a passes through the positioning hole 11. The width of the wide portion 10 b is wider than the positioning hole 11. The shoulder 13 is engaged with the electrode plate 8.

  The spacer 10 may be disposed such that the shoulder 13 faces the second substrate 2 as shown in FIG. 1, or the shoulder 13 faces the first substrate 1 as shown in FIG. 2. May be arranged. FIG. 2 is a cross-sectional view of another embodiment of the image display device. In FIG. 2, the same components as those shown in FIG.

  In the form of FIG. 1, the potential of the first conductor (electron-emitting device 3) (first potential), the potential of the second conductor 5 (second potential), the potential of the electrode plate 8 (third potential). The substrate in which the distance (d1) between the electrode plate 8 and the first substrate 1 and the distance (d2) between the electrode plate 8 and the second substrate 2 are opposite to the surface of the electrode plate 8 on the wide width portion 10b side. The electric field between the first plate 1 and the electrode plate 8 is E1, and the electric field between the electrode plate 8 and the substrate (second substrate 2) facing the surface of the electrode plate 8 on the narrow width portion 10a side. Is set so that the relationship of E1> E2 is established.

  Here, the electric field E1 is a value obtained by dividing the difference (V1) between the first potential and the third potential by the distance d1, and the electric field E2 is the difference (V2) between the second potential and the third potential. Divided by the distance d2.

  With the above setting, the Coulomb attractive force acting between the electrode plate 8 and the substrate (first substrate) facing the surface on the wide width portion 10b side of the electrode plate 8 is reduced to the surface on the narrow width portion 10a side of the electrode plate 8. This is larger than the Coulomb attractive force acting between the opposing substrate (second substrate) and the electrode plate 8. Therefore, the electrode plate 8 is held in contact with the stepped portion 13 of the spacer 10 by a Coulomb attractive force that acts between the electrode plate 8 and the substrate facing the wide-width portion side surface of the electrode plate 8, Maintain position.

  In the case of FIG. 1, the electric field between the electrode plate 8 and the second conductor 5 is smaller than the electric field between the electrode plate 8 and the electron-emitting device that is the first conductor. Therefore, F2 in FIG. 1 is smaller than F1. Therefore, the force applied to the second conductor (metal back) made of a thin film is small, and peeling of the second conductor (metal back) can be prevented.

  In general, it is known that when an electric field concentration structure such as a protrusion exists on the cathode side having a low potential, field emission occurs and induces discharge or the like. Such protrusions may occur inadvertently during the manufacturing process.

  However, in the case of the configuration of FIG. 2 to which the present invention is applied, such a problem can be solved. That is, in the case of FIG. 2, contrary to FIG. 1, the electric field between the electrode plate 8 and the electron-emitting device as the first conductor is better than the electric field between the electrode plate 8 and the second conductor 5. Is also small. Therefore, even if an unintentional protrusion or the like is generated between the electron-emitting device 3 and the electrode plate 8 in the manufacturing process, the electron-emitting device is protected without causing problems such as unnecessary electron emission and discharge. can do.

  In any configuration, since the electrode plate 8 is pressed against the wide portion of the spacer by the force generated by the electric field, the installation position of the electrode plate 8 is at the position of the boundary between the wide portion and the narrow portion of the spacer. Is accurately determined.

  Hereinafter, the potential of the electrode plate 8, the distance between the electrode plate 8 and the first substrate 1, and the distance between the electrode plate 8 and the second substrate 2 will be described in detail with specific examples.

  When PD-200 is used as the material of the first substrate 1 and the second substrate 2, the material of the electrode plate 8 is 426 alloy, 48 alloy (both Fe- Ni-based) can be used.

1 and 2, the Coulomb attractive force F1 acting in the space 14 formed by the first substrate 1 and the electrode plate 8, and the Coulomb attractive force acting in the space formed by the second substrate 2 and the electrode plate 8. F2 is
F1 = (1/2) ・ (Q11 ・ E11) = (1/2) ・ εS1 ・ (Vg / d1) ²
F2 = (1/2) · (Q12 · E12) = (1/2) · εS2 · {(Va−Vg) / d2} ²

  Q11 is an electric quantity between the first substrate 1 and the electrode plate 8, E11 is an electric field between the first substrate 1 and the electrode plate 8, and Q12 is an electric field between the second substrate 2 and the electrode plate 8. E12 is the electric field between the second substrate 2 and the electrode plate 8, ε is the vacuum dielectric constant, Va is the potential difference between the electron-emitting device 3 and the second conductor 5, and Vg is the electron-emitting device. 3 and the electrode plate 8, d1 is the distance between the first substrate 1 and the electrode plate 8, S1 is the area of the electrode plate 8, d2 is the distance between the second substrate 2 and the electrode plate 8, S2 is the first It is the voltage application area of the second substrate 2.

  Note that the potential of the electron-emitting device 3 was 0 V (hereinafter, Va may be referred to as an applied voltage of the second conductor, and Vg may be referred to as an applied voltage of the electrode plate).

  In the present embodiment, as shown in FIG. 1, when the surface of the electrode plate 8 on the wide portion 10b side faces the first substrate 1, F1> F2, that is, Q11 · E11> Q12 · E12 holds. Thus, the potential Vg of the electrode plate 8, the distance d1 between the electrode plate 8 and the first substrate 1, and the distance d2 between the electrode plate 8 and the second substrate 2 are set.

  As shown in FIG. 2, when the surface of the electrode plate 8 on the wide portion 10b side faces the second substrate 2, F2> F1, that is, Q12 · E12> Q11 · E11 is established. The potential Vg of the electrode plate 8, the distance d1 between the electrode plate 8 and the first substrate 1, and the distance d2 between the electrode plate 8 and the second substrate 2 are set.

  In both cases of FIGS. 1 and 2, Q11 and Q12 are the charges on the front and back of the electrode plate 8, and Q11 and Q12 are equal. Therefore, the relative relationship (magnitude relationship) between F1 and F2 can be ignored. I do not care.

Here, the magnitude of the Coulomb force acting on the electrode plate 8 | F1−F2 | is a typical value for each parameter, specifically, vacuum dielectric constant: ε = 8.85E−12 [F / m The applied voltage of the second conductor 5: Va = 10 [kV], the applied voltage of the electrode plate 8: Vg = 6 [kV], the distance between the substrate and the electrode plate: d1 = d2 = 2 [mm] The calculation is performed using the area of the substrate and the electrode plate: S1 = S2 = 80000 [mm ² ]. In this case, | F1−F2 | = 17.7 [N].

  Here, the weight of the electrode plate 8 is estimated to be about 10 [N] when the material of the electrode plate 8 is 426 alloy or 48 alloy and the thickness is 0.15 [mm]. Therefore, the Coulomb force (| F1−F2 |) is sufficiently larger than the dead weight of the electrode plate 8. For this reason, for example, the direction from the wide part to the narrow part of the spacer 10, the potential of the electrode plate 8, the distance between the electrode plate 8 and the first substrate 1, and the distance between the electrode plate 8 and the second substrate 2 By appropriately setting the distance and the like, the electrode plate 8 can be held in contact with the shoulder 13.

  In the present embodiment, the phosphor layer 4 is provided on the second substrate 2, the first substrate 1 has the electron-emitting device 3 provided on the surface facing the second substrate 2, and The potential of the second conductor 5 is higher than the potential of the electron-emitting device 3.

  Then, the electrode plate 8 is regulated to a desired potential for controlling the electrons emitted from the electron-emitting device 3 toward the phosphor layer 4 (for example, converging the electrons emitted from the electron-emitting device 3 or correcting the trajectory thereof). Therefore, the position of the electrode plate 8 for electronic control is fixed by the shoulder portion (step portion) 13 of the spacer by the Coulomb force.

  Therefore, it is possible to prevent the displacement of the electron beam and the deterioration of the discharge resistance accompanying the displacement of the electrode plate 8. Therefore, it is possible to prevent the image display performance from deteriorating.

  Note that the shape of the spacer 10 is not limited to a shape in which two prisms having different widths as shown in FIGS. 1 and 2 are combined, and can be appropriately changed.

  3 and 4 are perspective views showing other examples of the spacer 10. 3 and 4, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

  The shape of the spacer 10 may be, for example, a shape combining two cylinders having different diameters as shown in FIG. 3, or a combination of two prisms having different widths as shown in FIG. However, the shape may be shorter than the spacer 10 shown in FIGS. The shape of the positioning hole 11 provided in the electrode 8 is preferably changed as appropriate according to the shape of the spacer 10.

  Moreover, the image display apparatus shown in FIG. 1 or FIG. 2 can be manufactured by one of the following two methods, for example.

  5 and 6 are explanatory diagrams for explaining the first manufacturing method, and FIGS. 7 and 8 are explanatory diagrams for explaining the second manufacturing method.

  5 to 8, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

  First, the first manufacturing method will be described.

  As shown in FIGS. 5 and 6, the narrow plate 10a is fitted into the positioning hole 11 with the clearance 12 between the inner surface of the positioning hole 11 and the narrow plate 10a, and the electrode plate 8 is brought into contact with the shoulder 13 of the spacer 10 (see FIGS. 5A and 6A).

  After positioning and fixing the electrode plate 8 on which the spacer 10 is placed with respect to the first substrate 1 or the second substrate 2, the second substrate 2 or the first substrate 1 is fixed to the first substrate 1. Or it positions and fixes with respect to the 2nd board | substrate 2 (refer FIG.5 (b), FIG.6 (b)).

  Next, the second manufacturing method will be described.

  As shown in FIGS. 7 and 8, the electrode plate 8 is positioned and fixed with respect to the first substrate 1 or the second substrate 2 (see FIGS. 7A and 8A) and then narrowed. The width portion 10 a is fitted into the positioning hole 11, the shoulder portion 13 is brought into contact with the electrode plate 8, and then the second substrate 2 or the first substrate 1 is attached to the electrode plate 8 and the spacer 10. Position and fix to the 1st board | substrate 1 or the 2nd board | substrate 2 (refer FIG.7 (b) and FIG.8 (b)).

  In addition, as shown in FIG. 9, in consideration of automation of assembly work, the relief holes (relief portions) 18 of the gripping portions 17 of the spacers 10 are provided on the electrode plate 8, which increases work efficiency. Desirable from.

  FIG. 9A is a perspective view for explaining the electrode plate 8, the spacer 10, the gripping portion 17, and the escape hole 18, and FIG. 9B is a cross-sectional view taken along line BB in FIG. 9A. FIG. In FIG. 9B, what is indicated by a two-dot broken line indicates a state when the spacer 10 and the gripping portion 17 are moved in the direction of arrow a. In FIG. 9, the same components as those shown in FIG.

  Supplementing FIG. 9, conventionally, the work of penetrating the narrow portion 10a of the spacer 10 into the positioning hole 11 of the electrode plate 8 has a problem that the human load is large due to the work amount and the denseness. For this reason, it has been desired to reduce the work load and improve the work efficiency.

  Therefore, it is conceivable that the narrow portion 10a is automatically passed through the positioning hole 11 while the grip portion 17 grips the spacer 10. However, when the gripping portion 17 attempts to automatically penetrate the narrow width portion 10 a through the positioning hole 11, when the gripping portion 17 comes into contact with the electrode plate 8, the gripping portion 17 causes the narrow width portion 10 a to pass through the positioning hole 11. There is a possibility that it will be difficult to penetrate.

  In the embodiment shown in FIG. 9, the escape hole 18 of the gripping portion 17 is provided on the electrode plate 8, so that the gripping portion 17 performs an operation of automatically penetrating the narrow width portion 10 a through the positioning hole 11. At this time, it is possible to prevent the gripping portion 17 from coming into contact with the electrode plate 8. Therefore, it is possible to automate and increase the efficiency of the operation of penetrating the narrow width portion 10a through the positioning hole 11.

  Further, as shown in FIG. 10, in consideration of workability when the electrode plate 8 is handled in a state where the spacer 10 is placed, several points along the longitudinal direction of the spacer 10, the spacer 10 and the electrode plate 8 It is also desirable from the point of work efficiency to provide the temporary fixing part 19 for temporarily fixing the.

  As an example of the temporary fixing method, it is desirable to use an inorganic adhesive as the temporary fixing portion 19 in consideration of a small amount of degassing, and pot a small amount of the adhesive with a dispenser or the like. 10A is a perspective view for explaining the electrode plate 8, the spacer 10, and the temporary fixing portion 19, and FIG. 10B is a cross-sectional view taken along the line CC in FIG. 10A. It is. In FIG. 10, the same components as those shown in FIG.

  In the embodiment described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration. For example, the present invention can be applied not only to an electron beam display (FED) but also to other image display devices.

It is explanatory drawing which shows schematic structure of the image display apparatus of one Embodiment of this invention. It is sectional drawing which shows schematic structure of the image display apparatus of other embodiment of this invention. It is a perspective view which shows the one part schematic structure of the image display apparatus of other embodiment of this invention. It is a perspective view which shows the one part schematic structure of the image display apparatus of other embodiment of this invention. It is sectional drawing for demonstrating one manufacturing process of the image display apparatus shown in FIG. FIG. 3 is a cross-sectional view for explaining a manufacturing process of the image display device shown in FIG. 2. It is sectional drawing for demonstrating the other manufacturing process of the image display apparatus shown in FIG. It is sectional drawing for demonstrating the other manufacturing process of the image display apparatus shown in FIG. It is explanatory drawing which shows the one part schematic structure of the image display apparatus of other embodiment of this invention. It is explanatory drawing which shows the one part schematic structure of the image display apparatus of other embodiment of this invention.

Explanation of symbols

1 First board (first conductor)
2 Second substrate 4 Light emitting member 5 Second conductor 8 Electrode plate 10 Spacer 10a Narrow portion 10b Wide portion 11 Positioning hole 13 Shoulder portion (step portion)

Claims (3)

A first substrate having a first conductor defined at a first potential;
A second substrate having a second conductor defined at a second potential different from the first potential;
An electrode plate disposed between the first substrate and the second substrate and defined at a third potential;
A spacer having a narrow portion and a wide portion, and penetrating the electrode plate at the narrow portion and locking the electrode plate at the wide portion to define a distance between the first substrate and the second substrate An image display device comprising:
An image display device characterized in that a wide portion of the spacer is located between the first substrate and the electrode plate and satisfies the following relationship.
V1 / d1> V2 / d2
here,
V1: Potential difference between the first potential and the third potential
V2: Potential difference between the second potential and the third potential d1: Distance between the first substrate and the electrode plate d2: Distance between the second substrate and the electrode plate   The first substrate includes an electron-emitting device, and the second substrate includes a light-emitting member that emits light upon irradiation with electrons emitted from the electron-emitting device. Image display device.   The image display apparatus according to claim 2, wherein the second conductor is a thin film conductor that covers the light emitting member.

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