JP2850014B2 - Image forming device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image forming apparatus using an electron source.

[Prior art] Conventionally, as an element which can obtain electron emission with a simple structure, for example, MIElinson
And the like are known. [Radio Engineering Electron Phys. Vol. 10, pp. 1290-1296,
1965] Examples of this type of electron-emitting device include those using a SnO ₂ (Sb) thin film developed by Elinson et al. And those using an Au thin film [G. Dittmer: “thinSolid Films”. Films "), 9, 317,
(1972)], using ITO thin film [M. Hartwell and C. Fonstad “Ie Ei E Trans” E D Conf. (M.Ha
rtwell and CGFonstad: “IEEE Trans.ED Conf.”) 519
, (1975)], and those based on carbon thin films [Hisashi Araki et al., “Vacuum”, Vol. 26, No. 1, p. 22, (1983)].

In addition to the above, many promising electron-emitting devices such as a thin-film hot cathode and a MIM-type electron-emitting device have been reported.

Together with the rapid progress of film formation technology and photolithography technology, it is becoming possible to form a large number of elements on a substrate, and as a multi-electron beam source,
It is expected to be applied to various image forming apparatuses such as a fluorescent display tube, a flat panel CRT, and an electron beam drawing apparatus.

[Problems to be Solved by the Invention] However, when these elements are applied to an image forming apparatus, generally, a large number of elements are arranged and formed on a substrate,
Each element is electrically wired with thin or thick electrodes,
Although used as a multi-electron beam source, a phenomenon occurs in which a voltage applied to each element varies due to a voltage drop caused by wiring resistance. As a result, the current amount of the electron beam emitted from each of the emission elements varies, causing a problem that uneven brightness occurs in a formed image.

10 and 11 are diagrams for explaining this problem in more detail. In both figures, (a) is an equivalent circuit diagram including an electron-emitting device, a wiring resistance, and a power supply, and (b) is a diagram showing each electron-emitting device. FIG. 4 is a diagram showing potentials of a positive electrode and a negative electrode of the device, and FIG. 4C is a diagram showing a voltage applied between the positive and negative electrodes of each device.

FIG. 10 (a) shows N electron-emitting devices connected in parallel.
D ₁ to D _N and shows the circuit which connects the power source V _E, a positive electrode and a positive electrode of the device D ₁ of the power supply, also is obtained by connecting the negative electrode of the negative electrode and device D _N of the power supply. Further, the common wiring connecting the elements in parallel has a resistance component of r between adjacent elements as shown in the figure. (In an image forming apparatus, pixels serving as electron beam targets are usually arranged at equal pitches. Therefore, electron-emitting devices are also arranged at equal spatial intervals, and the wiring connecting them has a width or film thickness. Unless the thickness varies in manufacturing, the electrons have the same resistance value between the electrons.) Further, all the electron-emitting devices D _{1 to DN} have substantially the same resistance value Rd.

FIG. 10B shows the potentials of the positive electrode and the negative electrode of each element in the circuit diagram of FIG. 10A. The horizontal axis in the figure is
D ₁ indicates the element number to D _N, the vertical axis represents the potential. The symbol ● represents the positive electrode potential of each element, and the symbol Δ represents the negative electrode potential. For easy understanding of the potential distribution tendency, the ● symbol (■ symbol) is connected by a solid line for convenience.

As apparent from the figure, the voltage drop is not necessarily occur uniformly due to the wiring resistance r, in the case of the positive electrode side is a steep closer to element D _1, steeply closer to the device D _N in the negative electrode side in the opposite It has become. This is because, on the positive electrode side, the current flowing through the wiring resistance r increases as it approaches D ₁ , and on the negative electrode side, D _N
The larger the current, the larger the current flows.

FIG. 3C is a graph plotting the voltage applied between the positive and negative electrodes of each element. The horizontal axis represents device numbers D ₁ to D _N in the figure, the vertical axis represents respectively the applied voltage, conveniently for clarity the same tendency as FIG. (B) Are connected by a solid line.

As is clear from this figure, in the case of the circuit as shown in FIG. 3A, a higher voltage is applied closer to the elements (D ₁ and D _N ) at both ends, and the applied voltage is higher at the elements near the center. Become smaller.

Therefore, the electron beam emitted from each electron-emitting device has a larger beam current at the device at both ends, which is extremely inconvenient when applied to an image forming apparatus. (For example, the density of the image near the both ends is high, and the density near the center is low.) On the other hand, FIG. 11 shows one side of the element row connected in parallel (the element D in this drawing). _This is the case where the positive and negative electrodes of the power supply are connected to ( ₁ ). In the case of such a circuit, the positive electrode side as shown in FIG. (B), the voltage drop due to the wiring resistance r with the negative electrode side closer to D ₁ increases.

Therefore, the voltage applied to each device becomes a large closer to D ₁ as shown in FIG. (C), to be applied as an image forming apparatus was very inconvenient.

As described above, the degree of variation of the applied voltage for each element as shown in the two examples depends on the total number N of elements connected in parallel and the element resistance.
Although it differs depending on the ratio of Rd to the wiring resistance r (= Rd / r) or the connection position of the power supply, in general, the dispersion becomes more remarkable as N is larger and Rd / r is smaller, and as shown in FIG. The connection method shown in FIG. 11 has a larger variation in the voltage applied to the element.

For example, in the connection method of FIG. 10, the element resistance Rd = 1 kΩ, r = 10 m
In the case of Ω, if N = 100, comparing the element with the largest applied voltage with the element with the smallest applied voltage, V _max : V _min = 102: 100
However, if N = 1000, V _max : V _min = 472: 100
Then, the rate of variation increases.

When N = 1000, Rd = 1 kΩ, and r = 1 mΩ, V _max :
V _min = 127: about 100, but when r = 10 mΩ, V
_The degree of variation becomes large, for example, _max : V _min = about 472: 100.

As described above, when a plurality of electron-emitting devices having the same characteristics are connected in parallel, the voltage effectively applied to each device varies for each device due to a voltage drop caused by wiring resistance. The emission amount of the electron beam becomes uneven, which is inconvenient when applied as an image forming apparatus.

In particular, when an attempt is made to realize a large-capacity display device having a large number of pixels (that is, a large N), the rate of the above-mentioned variation becomes remarkable, and the density (density) unevenness of the image has become a serious problem.

Further, another problem will be described with reference to FIGS. 9 (a) to 9 (c). FIG. 9 (a) shows an outline of a conventional image forming apparatus using a surface conduction electron-emitting device. In the figure, 1 is an insulating substrate, 2 is a high potential side wiring, 2a is a high potential side electrode, 3
Is the low potential side wiring, 3a is the low potential side electrode, 4 is the electron emission section, 20
Is a modulation electrode, 12 is an insulating layer, 7 is a glass body, 8 is a transparent electrode, 9 is a phosphor, 10 is a face plate, 11 is a bright spot, and 15 is an insulating support.

9 (b) is a cross-sectional view taken along the line CC of FIG. 9 (a), and FIG. 9 (c) is a cross-sectional view taken along the line DD of FIG. 9 (a).

When such an image forming apparatus is operated for a long time, a conductive substance is gradually deposited on the side surface of the insulating support body 15 for electrically insulating the face plate 10 from other parts and physically supporting the face plate 10, thereby causing insulation failure. There is also a major problem that this causes the image forming apparatus to stop functioning.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of preventing poor insulation of a support supporting a face plate in the above-described configuration. Another object of the present invention is to provide an image forming apparatus capable of preventing the insulation failure of the support and suppressing a variation in voltage applied to the electron-emitting device from element to element. .

[Means for Solving the Problem (and Action)] The configuration of the present invention that achieves the above object is as follows.

That is, in the present invention, a substrate provided with an electron-emitting device and a face plate provided with a phosphor are arranged to face each other via a support, and the phosphor is irradiated with an electron beam emitted from the electron-emitting device. An image forming apparatus for forming an image by using a part of a wiring portion of the electron-emitting device, wherein at least a part of the support is shielded from the electron beam. is there.

The image forming apparatus of the present invention further has the following features: "the wiring portion is partially thickened";"the support is insulative";"The wiring portions are both provided directly on the substrate", "The support is provided between a plurality of adjacent wiring portions", "The support is provided on the wiring portion. "Provided with a layer functioning as a modulation electrode between the substrate and the wiring portion";"the electron-emitting device is of a surface conduction type"; The electron-emitting device is a thermionic electron-emitting device "," the longitudinal direction of the electron-emitting portion constituting the electron-emitting device and the longitudinal direction of the support are arranged substantially perpendicularly ", Is also included.

In the present invention, as a specific configuration for shielding at least a part of the support from the electron beam, for example, the wiring arranged on the substrate may be partially thickened, and the thickened portion may be used. . That is, when viewed from the electron beam trajectory side, a configuration can be adopted in which at least a part of the side surface of the support supporting the face plate is hidden by the thickened portion of the wiring. Then, the conductive material does not deposit on the portion of the support that is shielded in this way during driving or the like, so that it is possible to prevent the occurrence of insulation failure and to prevent electrification due to electron beam flying or the like. You can also.

Further, as described above, when the wiring arranged on the substrate is partially thickened, the wiring resistance r is reduced and the element resistance Rd is reduced.
And the wiring resistance r (= Rd / r) can be increased,
Variations in the voltage effectively applied to each electron-emitting device can be suppressed for each device.

Example An example of the present invention will be described with reference to the drawings.

Embodiment 1 First, a first embodiment of the present invention will be described with reference to FIGS. 1 (a), 1 (b) and 1 (c).

FIG. 1A is a perspective view showing the configuration of the image forming apparatus of the present invention, and shows only six elements as a representative.
In FIG. 1 (a), 1 is an insulating substrate, 2 is a high potential side wiring, 2a is a high potential side electrode, 3 is a low potential side wiring, 3a is a low potential side electrode, 4 is an electron emitting portion, 20 Is a modulation electrode, 12 is an insulating layer, 7 is a glass body, 8 is a transparent electrode, 9 is a phosphor, 10 is a face plate, 11
Is a bright spot, and 15 is an insulating support.

As shown in FIG. 1 (a), in the first embodiment, the longitudinal direction of the electron-emitting portion 4 constituting the electron-emitting device and the longitudinal direction of the insulating support 15 are arranged vertically. .

FIG. 1B is a cross-sectional view taken along the line AA of FIG. 1A, and FIG. 1C is a cross-sectional view taken along the line BB of FIG. 1A. In the first embodiment, a surface conduction electron-emitting device in which a modulation electrode is provided on a substrate is used as an electron source, the length 1 of the electron-emitting portion of the device is 300 μm, and the wirings 2 and 3 are the first.
In FIG. (C), h ₁ = 30 μm, h ₂ = 30 μm, t = 40 μm, ω = 1
00 μm. Also, the width (W) of the insulating support 15 is 110 μm,
The height (H) was 150 μm, the potential of the high potential side electrode 2a was 14V, and the potential of the low potential side electrode 3a was 0V. The acceleration voltage applied to the face plate was about 180V. By the way, in the image forming apparatus having the structure shown in the conventional example of FIG. 9, unevenness in image density occurs, and due to poor insulation due to contamination of the side surface of the insulating support 15, it is possible to form an image correctly. After starting operation of the device 15
It was about 00 hours. However, in the image forming apparatus of the first embodiment, no image density unevenness was observed, and a correct image could be formed even after 3,500 hours had elapsed after the start of operation.

Next, an example of a method for manufacturing an electron source and a wiring in the image forming apparatus of the present invention will be described with reference to FIGS. FIG. 2 shows an AA cross section of FIG.

First, a modulation electrode group 20 is formed of Ni on a glass substrate 1 by a vacuum deposition method and a photolithographic etching process (see FIG. 2A). Then, an SiO2 as an insulating layer 12 is 1μm deposited by vacuum deposition method, removing the SiO ₂ of the unnecessary portion followed by photolithography etching process (see FIG. 2 (b)). Next, 1500 nm of Ni is deposited as a metal film for the electrodes 2a and 3a by a vacuum deposition method, and the electrodes 2a and 3a are formed by a photolithographic etching process (the electrode gap is set to 2).
μm, the length of the electron-emitting portion was 300 μm, and the width of the electrode was 8 μm. ) (See FIG. 2 (c)). Next, the Ag paste is patterned by a printing method and baked to produce wirings 2 and 3 (see FIG. 2 (d)). Finally, after a solution of the organic palladium compound was applied and baked, a normal forming process was performed to form the electron-emitting portion 4 (see FIG. 2 (e)).
The insulating support 15 was formed by a printing method using glass.

In FIG. 1, a surface conduction electron-emitting device is used as an electron source. In general, if the electron source emits electrons,
Any kind and shape may be used. Further, in the present embodiment, the wirings 2 and 3 are straight lines, but the present invention is not limited to this. Further, although the wirings 2 and 3 have the same dimensions and the same shape in FIG.
In general, different sizes and different shapes may be used.

Embodiment 2 A second embodiment of the present invention will be described with reference to FIG.

In the second embodiment, the electron emitting section 4 is used as an electron emitting element.
However, a thermionic emission electron source with a modulation electrode having a thickness of 1.0 μm, a width of 15 μm, and a length of 300 μm was used. FIG. 3 (a) shows the electron source substrate on which thermionic emission electron sources are formed only for six elements. FIG. 3 (b) shows a cross section taken along line EE of FIG. 3 (a).

In the present embodiment, the wirings 2 and 3 are h ₁ = 20 μm, h ₂ = 40 μm, t = 40 μm, and ω = 100 μm in FIG. 3B.

Also in this embodiment, similarly to the first embodiment shown in FIG. 1, density unevenness was not observed, and a correct image could be formed even after 3,500 hours had passed since the start of operation.

Next, an example of a method of manufacturing an electron source and a wiring in the image forming apparatus of the present embodiment will be described with reference to FIGS. FIG. 4 is a sectional view taken along line FF of FIG. 3 (a).

First, a modulated discharge group 20 is formed of Ni on a glass substrate 1 by a vacuum deposition method and a photolithographic etching process (see FIG. 4A). Next, SiO ₂ is used as the insulating layer 12,
Depositing 1 μm by a vacuum deposition method, and then removing unnecessary portions of SiO ₂ by a photolithography etching process (see FIG. 4B). Next, 7 μm of Cu is deposited for the supports 2b and 3b of the electron-emitting portion 4 by a vacuum deposition method (FIG. 4C).
reference). Next, 1.0 μm of Ta is deposited for the electrodes 2a, 3a and the electron-emitting portion 4 by a vacuum deposition method (see FIG. 4D). Next, the Ta layer is processed by a photolithographic etching process to form the electron emitting portions 4 (see FIG. 4E). Next, the Ag paste is patterned by a printing method and baked to form the wirings 2 and 3 (see FIG. 4 (f)). Finally, Cu is selectively etched to form a hollow structure of the electron-emitting portion 4 made of Ta (see FIG. 4 (g)).

Embodiment 3 A third embodiment of the present invention will be described with reference to FIG.

In the third embodiment, as the electron-emitting device, the modulation electrode pair electron-emitting device in the first embodiment is used, the wirings 2 and 3 are formed in a tiered form, and the insulating support 15 is provided on the wirings 2 and 3 to form a ladder. The electron emission part 4 was arranged behind the step.

Embodiment 4 A fourth embodiment of the present invention will be described with reference to FIG.

In the fourth embodiment, the electron-emitting device with the modulation electrode in the first embodiment is used as the electron-emitting device, the wirings 2 and 3 are L-shaped, and the insulating support 15 and the wirings 2 and 3 are both formed on the substrate 1. It was arranged to be located.

Embodiment 5 A fifth embodiment of the present invention will be described with reference to FIG.

In the fifth embodiment, the electron-emitting device with the modulation electrode in the first embodiment is used as the electron-emitting device, and the wirings 2 and 3 are formed in the form of a step. The insulating support 15 and the wirings 2 and 3 are both formed on the substrate 1. The electron emission portion 4 was positioned on the front side of the tier.

Embodiment 6 A sixth embodiment of the present invention will be described with reference to FIG.

In the sixth embodiment, the electron-emitting device with the modulation electrode in the first embodiment is used as the electron-emitting device, the wirings 2 and 3 are of a block type, and the insulating support 15 and the wirings 2 and 3 are both on the substrate 1. It was arranged to be located.

[Effects of the Invention] As described above, according to the present invention, at least a part of the support that supports the face plate is configured to be shielded from the electron beam, so that the conductive material is deposited on the shield part. In addition, it is possible to prevent occurrence of insulation failure, prevent charging due to flying of an electron beam or the like, and form a correct image for a long period of time.

In particular, when the wiring arranged on the substrate is partially thickened, and the thickened portion is used to shield the support for supporting the face plate, in addition to the above effects, each electron emission Variations in the voltage that is effectively applied to the elements for each element can be suppressed to a small level, and image density unevenness can be eliminated.

[Brief description of the drawings]

FIG. 1 is a perspective view and a cross-sectional view showing a first embodiment of the present invention. FIG. 2 is a process diagram showing an example of a method for manufacturing an electron source substrate according to the first embodiment of the present invention. FIG. 3 is a perspective view and a sectional view showing a second embodiment of the present invention. FIG. 4 is a process chart showing an example of a method of manufacturing an electron source substrate according to the second embodiment of the present invention. FIG. 6 is a sectional view showing a third embodiment of the present invention. FIG. 6 is a sectional view showing a fourth embodiment of the present invention. FIG. 7 is a sectional view showing a fifth embodiment of the present invention. FIG. 8, FIG. 8 is a sectional view showing a sixth embodiment of the present invention, FIG. 9 is a perspective view and a sectional view showing a conventional example, and FIGS. 10 and 11 show problems of the conventional example. FIG. DESCRIPTION OF SYMBOLS 1 ... Insulating substrate (glass substrate) 2 ... High potential side wiring 2a ... High potential side electrode 2b, 3b ... Support body 3 ... Low potential side wiring 3a ... Low potential side electrode 4 ... Electron emission Part 7 Glass body 8 Transparent electrode 9 Phosphor 10 Faceplate 11 Bright spot 12 Insulating layer 15 Insulating support 20 Modulation electrode

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ichiro Nomura 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Toshihiko Takeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Yoshikazu Banno 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-61-133539 (JP, A) (58) Fields investigated (Int .Cl. ⁶ , DB name) H01J 31 / 12,31 / 15

Claims (10)

(57) [Claims] 1. A substrate provided with an electron-emitting device and a face plate provided with a phosphor are disposed to face each other with a support interposed therebetween.
In an image forming apparatus that forms an image by irradiating the phosphor with an electron beam emitted from the electron-emitting device, at least a part of the support is formed by using a part of a wiring portion of the electron-emitting device. An image forming apparatus characterized in that it is shielded from an electron beam. 2. The image forming apparatus according to claim 1, wherein the wiring portion is partially thickened. 3. The image forming apparatus according to claim 1, wherein the support is insulating. 4. The image forming apparatus according to claim 1, wherein said support and said wiring portion are both provided directly on said substrate. 5. The image forming apparatus according to claim 4, wherein said support is provided between a plurality of adjacent wiring portions. 6. An image forming apparatus according to claim 1, wherein said support is provided on said wiring portion. 7. An image forming apparatus according to claim 1, wherein a layer functioning as a modulation electrode is provided between said substrate and said wiring portion. 8. An image forming apparatus according to claim 1, wherein said electron-emitting device is of a surface conduction type. 9. The image forming apparatus according to claim 1, wherein said electron-emitting device is a thermionic electron-emitting device. 10. The image forming apparatus according to claim 1, wherein a longitudinal direction of the electron-emitting portion constituting the electron-emitting device and a longitudinal direction of the support are arranged substantially perpendicularly. apparatus.