JP2961421B2 - Image forming apparatus and driving method thereof - Google Patents

Description

The present invention relates to a plurality of electron-emitting devices, a grid electrode,
The present invention relates to an image forming apparatus including a plurality of pixels and a driving method of the image forming apparatus.

[Prior Art] Conventionally, a thin image display device in which a plurality of electron sources spread in a plane and phosphor targets each receiving irradiation of an electron beam from the electron source are opposed to each other is known. Kaisho 56
-28445. According to this method, since it is not necessary to deflect the electron beam, it is expected that an image display device having a very small depth compared to a general CRT can be realized. Unfortunately, however, the use of a coil-type heater type cathode as the electron source results in low electron emission efficiency and a complicated structure, resulting in enormous power consumption and manufacturing cost of the device. Therefore, it has not been put to practical use.

Therefore, by using an electron source generally called a surface conduction electron-emitting device as an electron source instead of the coil-type heater-type heat cathode, the electron emission efficiency is improved and the structure is simplified, and the depth is extremely small. Practical use of the image display device has been considered.

Conventionally, devices that can emit electrons with a simple structure include, for example, MIElinson
Are known [Radio Engineering Electron Phys., Vol. 10, 1290-1296, 19
65 years].

This utilizes a phenomenon in which electrons are emitted when a current flows in a small-area thin film formed on a substrate in parallel with the film surface, and is generally called a surface conduction electron-emitting device.

As the surface conduction electron-emitting device, a device using a SnO ₂ (Sb) thin film developed by Elinson et al.
By thin film [G. dittmer: "Thin Solid Films", 9
Vol.317, (1972)], using ITO thin film [M.
Hartwell and C the Fonstad:
“I e e e e trans e de
Conf. ”(M. Hartwell and CGFonstad:“ IEEE Trans.
ED Conf. ") P. 519, 1975)], using a carbon thin film [Hisashi Araki et al .:" Vacuum ", Vol. 26, No. 1, p. 22, (1983)
Year)].

These surface conduction electron-emitting devices are: 1) obtain a high electron emission efficiency; 2) are easy to manufacture because of their simple structure; 3) can form and form a large number of devices on the same substrate; 4). It has advantages such as fast response speed, and has the potential to be widely applied in the future.

[Problems to be Solved by the Invention] However, in the above conventional example, the electron beam emitted from the surface conduction electron-emitting device has a crescent-shaped spreading characteristic, and thus has the following disadvantages.

(1) In order to focus an electron beam emitted from a surface conduction electron-emitting device to an arbitrary shape and size, a very complicated electron optical system is required.

(2) It is difficult to realize an image forming apparatus arranged at high density on the same substrate because of the spread characteristic peculiar to the element.

Further, in an image forming apparatus in which a large number of electron sources are arranged in a multi-array, when one element is deteriorated in characteristics or fails, the light emitting unit corresponding thereto also causes deterioration of light emission characteristics or disappearance of light emission. In a high-density integrated and arranged image forming apparatus, non-emission of one point on one screen is extremely remarkable,
This is not desirable for displaying high-definition images.

Furthermore, in an image forming apparatus using a multi-electron source, since a large number of electron emitting portions are arranged at several million locations at high density, it is practically impossible to repair or correct a failure after the device is completed.

Due to the above-mentioned problems, such surface conduction electron-emitting devices have not been actively applied in industry, and an image forming apparatus using a multi-electron source that can be made extremely thin has also been realized. Has not been reached.

The present invention has been made for the purpose of eliminating the above-mentioned drawbacks of the conventional example.

[Means for Solving the Problems] That is, the present invention provides at least a plurality of electron-emitting devices,
An image forming apparatus having a grid electrode and a plurality of pixels has an electrode for diffusing an electron beam from one electron-emitting device to a range where the plurality of pixels can be irradiated simultaneously, and furthermore, an electron beam from one electron-emitting device. The image forming apparatus is characterized in that the number of pixels that can simultaneously irradiate is variable.

The image forming apparatus is provided with an electrode capable of controlling the potential separately from the electron-emitting device, and a direct-current voltage applied to the electrode can positively expand the irradiation area of the electron beam emitted from the electron-emitting device. Thus, a plurality of pixels can be irradiated simultaneously with an electron beam emitted from one electron-emitting device, and the number of pixels that can be simultaneously irradiated with an electron beam emitted from this one electron-emitting device is made variable. Things.

Further, according to the present invention, in the driving method of the image forming apparatus, when some of the electron-emitting devices fail, the electron beams of the other electron-emitting devices should be irradiated with the electron beam from the failed electron-emitting device. Another object of the present invention is to provide a method of driving an image forming apparatus, which is characterized in that the light is diffused in a range where the pixels can be irradiated.

According to the driving method of the image forming apparatus, even if some of the electron-emitting devices fail and the emission of the electron beam is stopped, an extreme image is generated by using the electron beams emitted from the other electron-emitting devices. Can be prevented from decreasing.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a partial sectional view showing an embodiment of an image forming apparatus according to the present invention. In the figure, 1 is a glass substrate,
2 is a surface conduction electron-emitting device connected in parallel in one line, 3 is a focused diffusion electrode provided in the vicinity of each emission portion, 4 is a grid electrode, 5 is a phosphor, and 6 is a face coated with a phosphor. It is a plate.

In the above configuration, first, the glass substrate 1 is sufficiently organically washed, and then the focused diffusion electrode 3 is formed by using a normal photolithography technique or the like. At this time, the focusing and diffusion electrode is arranged in a direction orthogonal to the wiring direction of the emission element so that the focusing and diffusion electrode does not directly affect the electron emitting portion.

Next, a pair of electrodes having a minute interval of several hundreds to several tens of μm for forming an electron emitting portion are formed on the substrate 1 by using a photolithography technique. At this time, 1 μm of SiO ₂ was formed in advance in a portion intersecting with the focusing and diffusion electrode by sputtering to secure the insulating properties of both electrodes. The width of the electrode forming the emission section thus obtained is 200 μm, and the element pitch is 1 mm.

Next, an organic solvent containing an organic palladium compound between electrodes having a width of 200 μm (Catapaste-CCP manufactured by Okuno Pharmaceutical)
Then, the resultant was baked at 250 ° C. for 10 minutes in the air to make palladium fine particles to form a discontinuous film having an island structure (not shown). Thus, a multi-electron source having a 200 μm-wide emitting portion and deflection electrodes on both sides thereof was obtained.

Next, as shown in FIG.
The grid electrodes 4 were provided at intervals. At this time, 1
In order to obtain light emission at two locations with electron beams emitted from the emission portions, two grid holes are arranged at equal intervals from one emission portion. Grid hole diameter is 400μ
m, the pitch of the holes is 500 μm. Further, a face plate 6 coated with a phosphor was provided at a position 5 mm from the grid electrode to complete the apparatus.

The interior of the device thus obtained is maintained at a vacuum of about 1 × 10 ⁻⁶ Torr, a DC voltage of 14 V is applied to the electron-emitting device, 1 KV is applied to the grid, 5 KV is applied to the face plate, and the focusing and diffusion electrode is grounded. When the potential was set, a minute light emission was observed on the phosphor corresponding to the position of the grid hole.

Next, of the emission elements connected in parallel, one emission part was cut off, non-emission was performed, and the same experiment was performed again. As a result, two phosphors at positions corresponding to the non-emission part were found. Light emission stopped, and it was confirmed that two phosphors were irradiated with an electron beam at one emission part.

Further, when the device applied voltage was 14 V, the grid voltage was 1 KV, and the face plate voltage was 5 KV, a DC voltage was gradually applied to the focusing and diffusion electrode 3. A bright spot was observed again. Although the brightness of this luminescent spot was slightly darker than other brightnesses, the required emission intensity was obtained. FIG. 2 schematically shows how the electrons fly at this time.

In FIG. 2, grid holes 8 and 9 to be supplied with electrons from the non-emission emitting part 7 are provided with the focusing and diffusion electrodes 3.
A part of the electrons emitted from the emission part 2 expanded by the above is supplied, and the phosphors at the positions corresponding to 8 and 9 emit light.

Therefore, in the device manufactured in this example, it was possible to supply an electron beam to an adjacent pixel by appropriately selecting a voltage to be applied to the focusing and diffusion electrode.

Example 2 Next, as an image forming apparatus, an apparatus was prepared in which an emitted electron beam was focused beforehand by a focusing and diffusion electrode, and the electron beam was diffused when necessary. As shown in FIG. 3, similarly to the first embodiment, first, the glass substrate 1 is sufficiently organically washed, and then the focused diffusion electrode 3 is formed by using a usual photolithography technique or the like. At this time, the focusing and diffusion electrodes are arranged in a direction perpendicular to the wiring direction of the emission elements so that the focusing and diffusion electrodes do not directly affect the electron emitting portion.

Next, a 2 mm-thick spacer was placed on the electrode wiring portion on the substrate 1 provided with the emission portion and the focus diffusion electrode, and the grid electrode 4 and the face plate 6 were provided through the spacer in the same manner as in Example 1. The distance between the substrate 1 and the grid electrode 4 is 2 mm,
The distance between the grid electrode and the face plate is 4 mm.

When the device obtained in this way is kept at a vacuum of about 1 × 10 ⁻⁶ Torr, the voltage applied to the element is 14 V, the voltage applied to the grid is 500 V, the voltage applied to the face plate is 5 KV, and the voltage applied to the focusing diffusion electrode is 0 V. The electron beam emitted from the electron emitting portion 2 of the above-mentioned electron beam passed through four places of the grid holes 10, 11, 12, and 13, and formed fine emission luminescent spots at four places of the phosphor 5.

In order to focus the electron beam emitted from the electron emitting portion 2 only on the grid holes 11 and 12, various voltages were applied to the focusing and diffusion electrode 3.
Only the bright spots corresponding to the two locations of 12 were observed, confirming the effect of the focused diffusion electrode as in Example 1. In addition, since the electron beam can be focused and diffused by the voltage applied to the focusing / diffusion electrode, if the emission portions connected in parallel deteriorate in function or the like, part of the electron beams of the adjacent emission portions should be used. Thus, it was possible to avoid fatal damage as an image forming apparatus.

[Effects of the Invention] As described above, according to the present invention, (1) since the focused diffusion electrode can be provided on the same substrate in the vicinity of the emission portion, the emission electron beam can be easily focused and diffused.

(2) Since an arbitrary luminescent spot can be formed by an electron beam emitted from one emission portion, it is possible to provide an image forming apparatus which is hardly affected by a part of element deterioration and has little deterioration in image quality.

(3) Since the voltage of the focusing and diffusion electrode can be arbitrarily set,
The degree of freedom for the voltage and positional relationship of each electrode of the device is large.

The above effects are obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of one embodiment showing features of the present invention, FIG. 2 is a partial cross-sectional view of the device manufactured in Example 1,
FIG. 3 is a partial sectional view of the device manufactured in the second embodiment. DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Electron emission part 3 ... Focusing diffusion electrode 4 ... Grid electrode 5 ... Phosphor 6 ... Face plate 7 ... Non-emission emission part 8,9,10,11 , 12,13 …… Hole of grid electrode 14 …… Electron beam

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshikazu Sakano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Haruhito Ono 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Tetsuya Kaneko 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-63-237340 (JP, A) JP-A-63-150837 ( JP, A) JP-A-59-73837 (JP, A) JP-A-63-13246 (JP, A) Patent 2727225 (JP, B2) Patent 2727223 (JP, B2) (58) Fields investigated (Int. . ^6, DB name) H01J 1/30 H01J 31/08 - 31/18 G09G 3/00 - 3/38

Claims (2)

(57) [Claims] 1. An image forming apparatus comprising at least a plurality of electron-emitting devices, a grid electrode, and a plurality of pixels, an electrode for diffusing an electron beam from one electron-emitting device into a range where the plurality of pixels can be simultaneously irradiated. And 1
An image forming apparatus, wherein the number of pixels that can simultaneously irradiate an electron beam from one electron-emitting device is variable. 2. A driving method of an image forming apparatus according to claim 1, wherein when one of the electron-emitting devices fails, the electron beam from another electron-emitting device is replaced by the electron beam from the failed electron-emitting device. A method for driving an image forming apparatus, comprising: diffusing light to a range in which pixels to be irradiated can be irradiated.