JPH02299141A - Image forming device and driving method thereof - Google Patents

Abstract

PURPOSE:To facilitate the convergence and divergence of emitted electron beams by providing electron converging/diverging electrodes near electron emission sections of surface conductive type electron emitting elements, and expanding electron beams emitted by the potential of the electrodes in the horizontal direction. CONSTITUTION:Grid electrodes 4 to extract electrons are provided vertically above multiple surface conductive type electron emitting elements 2 connected in parallel on an insulating substrate 1 made of glass or the like, and a faceplate 6 coated with phosphors 5 is provided at the position corresponding to holes of electrodes 4. Converging/diverging electrodes 3 controlling the potential are provided separately from elements 2 between emission sections connected in parallel. Electron beams 14 emitted from elements 2 are positively expanded in the horizontal direction by the DC voltage applied to electrodes 3, and multiple phosphors 5 are illuminated by electron beams 14 emitted from one emission section 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus comprising an element that emits electrons in a vacuum and a face plate coated with a phosphor.

[Prior Art J] Conventionally, a thin image display device in which a plurality of planar electron sources and phosphor targets each receiving electron beam irradiation from the electron sources are opposed to each other has been developed. 1977
-28445.

According to this method, since there is no need to deflect the electron beam, it is expected that an image display device with a much smaller depth than a general CRT can be realized. Unfortunately, however, because a hot cathode in the form of a coiled heater is used as the electron source, the electron emission efficiency is low (and the structure is complicated, resulting in enormous power consumption and manufacturing costs for the device). For this reason, it has not yet been put into practical use.

Therefore, in place of the above-mentioned coiled heater-type thermal cathode, an electron source generally called a surface conduction type emitter is used as an electron source to improve electron emission efficiency and simplify the structure. The practical application of image display devices is being considered.

Conventionally, as an element that can emit electrons with a simple structure,
For example, M.I. Ellingson (M,I.

The cold cathode device announced by E. Elinson and others is well known.
tron.

Phys,) Volume 1O, pp. 1290-1296, 1
965].

This device utilizes the phenomenon that electrons are emitted when a current is passed through a small-area thin film formed on a substrate parallel to the film surface, and is generally called a surface conduction type emission device.

This surface conduction type emission device uses a 5nOt (Sb) thin film developed by Ellingson et al., as well as one using an Au thin film [G.
: Th1n 5olid FLlms”), Volume 9, 31
7, (1972)], by ITO thin film [M. Hartwell and C.J. Fonstad: “I.E.I.E.
D Conf'' (M, Hartweli and
C.G.Fonstad: “IEEE Tra.
ns, ED Conf, ”) page 519, 19
1. Carbon thin film [Hisashi Araki et al.: “
vacuum".

Vol. 26, No. 1, p. 22, (1983), etc. have been reported.

These surface conduction type emitters have the following properties: l) High electron emission efficiency can be obtained; 2) They have a simple structure and are therefore easy to manufacture; 3) A large number of elements can be arranged and formed on the same substrate; 4) It has advantages such as fast response speed, and has the potential to be applied to floors in the future.

[Problems to be Solved by the Invention] However, in the conventional example described above, since the electron beam emitted from the surface conduction type emitter has a crescent-shaped spreading characteristic, it had the following drawbacks.

(1) In order to focus the electron beam emitted from the surface conduction type emitter into an arbitrary shape and size, a very complicated electron optical system is required.

(2) Due to the spreading characteristics peculiar to the elements, it is difficult to realize an image forming apparatus in which the elements are arranged at high density on the same substrate.

Furthermore, in an image forming apparatus in which a large number of electron sources are arranged in a multi-array, when - elements deteriorate in characteristics or fail, the corresponding light-emitting section also suffers deterioration in its light-emitting characteristics or extinction of light emission. In image forming apparatuses that are densely integrated and arranged, - non-emission of light at one point on the screen is extremely noticeable and is not desirable for displaying high-definition images.

Furthermore, in an image forming apparatus using a multi-electron source, an extremely large number of electron-emitting parts (several million) are arranged at high density, so that it is virtually impossible to repair or correct a malfunction after the apparatus is completed.

Due to the above-mentioned problems, such surface conduction type emitters have not been actively applied in industry, and furthermore, image forming devices using multi-electron sources that can be made extremely thin have not been realized. has not yet been reached.

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

[Means for Solving the Problems] In order to solve the above problems, the means taken in the present invention will be explained with reference to FIG. 1, which best represents the measures taken in the present invention.

In the present invention, a grid electrode 4 for extracting electrons is provided vertically above a plurality of surface conduction electron-emitting devices 2 connected in parallel on an insulating substrate such as glass, and a grid electrode 4 is provided for drawing out electrons. A face plate 6 coated with a phosphor 5 is provided at the position where an image is formed and left. Further, a focusing diffusion electrode 3 whose potential can be controlled separately from the element is provided between each of the emission parts connected in parallel, and the focusing diffusion electrode 3
A method is taken in which the electron beam emitted from the emitting element is actively spread in the horizontal direction by a DC voltage applied to the emitting element, and the electron beam emitted from one emitting part causes a plurality of phosphors to emit light.

The surface conduction type emission device used in the present invention is a device that emits electrons by a strong electric field generated in a minute space. Although some aspects of the principle are still unclear, as a result of studies conducted by the present inventors, the spread of the electron beam emitted from this device is It has been revealed that this is caused by electrons with an initial velocity equivalent to about 1/2. Therefore, in order to focus the electron beam from this element to the same level as or less than the emission part, the above initial velocity should be ignored and the electron beam should be accelerated at a high enough voltage, and the distance from the element to the emission part should be made infinitely close or However, a complicated electron optical system must be used, which is inconvenient for the image forming apparatus.

Therefore, in the present invention, the above-mentioned characteristics of the present device are actively utilized to create an image forming device.By applying an arbitrary voltage to the focusing/diffusion electrode near the emission part, the electron beam can be diffused and focused. It is something that causes

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

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
1 is a surface conduction electron-emitting device connected in parallel in a line, 3 is a focusing diffusion electrode provided near each emission part, 4 is a grid electrode, 5 is a phosphor, and 6 is a face plate coated with a phosphor. It is.

In the above configuration, first, after the glass substrate l is sufficiently organically cleaned,
The focusing diffusion electrode 3 is formed using a normal photolithography technique or the like. At this time, the focusing/diffusion electrode is arranged in a direction perpendicular to the wiring direction of the emitting element so that the focusing/diffusion electrode does not directly affect the electron emitting section.

Next, a pair of electrodes having minute intervals of several hundred to several tens of electrodes, which will form an electron emitting region, are formed on the substrate 1 using photolithography technology. At this time, 5ift of 1pm was previously formed by sputtering on the portion intersecting with the focusing diffusion electrode to ensure insulation between both electrodes. The width of the electrode forming the emission part thus obtained was 200 ptm.
and the element pitch is Ll.

Next, an organic solvent containing an organic palladium compound (Catapace manufactured by Okuno Pharmaceutical Industries)-CCP was used between the electrodes with a width of 200 μm.
), the palladium was baked in air at 250°C for 10 minutes to make the palladium into fine particles and form a discontinuous film with an island structure (not shown). A multi-electron source with deflection electrodes on both sides was obtained.

Next, as shown in FIG.
Grid electrodes 4 were provided at intervals of Im.

At this time, in order to obtain light emission from two places with the electron beam emitted from one emission part, the two grid holes were arranged at equal intervals from one emission part. The diameter of the grid holes is 400 Pm, and the pitch of the holes is 500 Pm. Further, a face plate 6 coated with phosphor was provided at a position 511Q+ from the Bree Rad electrode to complete the device.

The interior of the device thus obtained was heated to I
A DC voltage of 14 cm is applied to the electron-emitting device while maintaining a vacuum of about
Apply V to the grid, I KV to the faceplate, 5 to the faceplate.
When KV was applied and the focusing/diffusion electrode was brought to earth potential, minute light emission was observed on the phosphor corresponding to the position of the grid hole.

Next, among the emitting elements connected in parallel, one of the emitting parts was separated and made non-emissive, and the same experiment was conducted again.
It was confirmed that two phosphors were irradiated with electron beams by one emission part.

Furthermore, when using the same device, a DC voltage was gradually applied to the focusing diffusion electrode 3 with the element applied voltage of 14 V, the grid voltage of IKV, and the face plate voltage of 5 KV, resulting in a voltage of 20 V.
Bright spots were observed again at the positions where no light was emitted due to the non-emission. Although the brightness of this bright spot was slightly lower than other brightnesses, the required luminous intensity was obtained.

Figure 2 schematically shows how the electrons fly at this time.

In FIG. 2, the grid holes 8 and 9 to which electrons should be supplied from the non-emissive emitter 7 are connected to the focusing and diffusing electrode 3.
A part of the electrons emitted from the emitting part 2 spread out by is supplied to cause the phosphor at the position corresponding to 8.9 to emit light.

Therefore, in the device manufactured in this example, it was possible to supply electron beams even to adjacent pixels by appropriately selecting the voltage applied to the focusing diffusion electrode.

11) Next, as an image forming apparatus, an apparatus was manufactured in which the emitted electron beam was focused in advance by a focusing and diffusing electrode, and the electron beam was diffused when necessary. As shown in FIG. 3, in the same manner as in Example 1, first, the glass substrate 1 is sufficiently organically cleaned, and then the focusing diffusion electrode 3 is
form.

At this time, the focusing/diffusion electrode is arranged in a direction perpendicular to the wiring direction of the emitting element so that the focusing/diffusion electrode does not directly affect the electron emission section.

Next, a 2 ml 11 thick spacer was placed on the electrode wiring section on the substrate 1 on which the emission section and focusing/diffusion electrode were provided, and the grid electrode 4 and face plate 6 were provided via the spacer in the same manner as in Example 1. The distance between the substrate 1 and the grid electrode 4 is 2
mm, distance between grid electrode and face plate is 4 mm
It is.

The device thus obtained is kept in a vacuum of about l x 10-'Torr, and when the voltage applied to the element is 14V, the voltage applied to the grid is 500V, the voltage applied to the face plate is 5KV, and the voltage applied to the focusing diffusion electrode is OV, one place The electron beam emitted from the electron emission part 2 of
．． The light passed through the four locations of 12.13 and formed minute light-emitting bright spots at four locations on the phosphor 5.

Therefore, in order to focus the electron beam emitted from the electron emitter 2 only on the grid holes 11 and 12, the focusing diffusion electrode 3
When various voltages were applied to -15V, only two bright spots corresponding to approximately 11.12 were observed.
As in Example 1, the effect of the focusing and diffusing electrode was confirmed.

In addition, since the electron beam can be focused and diffused by the voltage applied to the focusing/diffusion electrode, in the event of functional deterioration in the parallel-connected emitters, part of the electron beams from the adjacent emitters can be used. It was possible to avoid fatal damage to the image forming device.

[Effects of the Invention] As described above, according to the present invention, (1) the focusing and diffusing electrode can be provided on the same substrate near the emission part, so that the emitted electron beam can be easily focused and diffused.

(2) Since an arbitrary bright spot can be formed by the electron beam emitted from one emission part, it is possible to provide an image forming apparatus that is less susceptible to deterioration of some elements (and has less deterioration in image quality).

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

There are effects as described above.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of an embodiment showing the features of the present invention, FIG. 2 is a partial sectional view of the device manufactured in Example 1,
FIG. 3 shows a partial cross-sectional view of the device manufactured in Example 2. DESCRIPTION OF SYMBOLS 1... Glass substrate 2... Electron emitting part 3... Focusing diffusion electrode 4... Grid electrode 5... Fluorescent material 6... Face plate 7... Emitting part made non-emissive 8, 9.10.11, 12.13...Grid electrode hole 14...Electron beam

Claims (3)

[Claims] (1) An image forming apparatus including at least a plurality of surface conduction type emission elements, a grid electrode, and a microscope screen, which has an electron beam focusing and diffusion electrode near the electron emission part of the element, and the electric potential of the electrode causes the element to An image forming apparatus characterized in that the number of pixels formed on the microscope screen is variable. (2) A method for driving an image forming apparatus according to claim 1, characterized in that when some elements in the image forming apparatus fail, a positive voltage is applied to the electron beam focusing diffusion electrode to generate a diffusion function. . (3) In the image forming apparatus, the electron beam focusing diffusion electrode is provided with a focusing function when all the elements are operating normally, and the focusing function is stopped when some elements are malfunctioning. How to drive the device.