JPH07302551A - Image forming device - Google Patents

Abstract

PURPOSE:To realize the high density of a picture element, and realize the high density and high definition of a display image by arranging plural phosphors presenting mutually different light emitting colors in the minor axis direction of a light emitting part shape formed of radiation of an electron beam. CONSTITUTION:Particulates 8 being an electron emitting material are arranged between electrodes 1 and 2, and electron emitting parts 5 are formed by heat treatment. Next, elements having the parts 5 having a shape corresponding to phosphors of respective colors of red (R), green (G) and blue (B) having mutually different light emitting colors, are arranged by six elements in order on a single line, and similar line-shaped elements are also constituted by three lines as a whole. The phosphors of three colors of R, G and B are arranged in the minor axis direction of a light emitting part 7 on a phosphor board 6, and a single picture element is constituted of the three-color phosphors adjacent to each other on the same line. Thereby, since the picture element close to a square can be constituted, the density of the picture element is enhanced, and even when an electron emitting element whose part 7 presents a long and narrow shape is used as an electron source, the high density and high definition of a display image can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image by using an electron emitting device, particularly a cold cathode type electron emitting device as an electron source.

[0002]

2. Description of the Related Art Conventionally, as an element capable of emitting electrons with a simple structure, for example, "Radio Engineering Electron Physics (Radio En
g. Electron Phys. ) ”1965,
A cold cathode device by MI Elinson et al. Described in Vol. 10, pp. 1290 to 1296 is known.

This utilizes a phenomenon in which electrons are emitted from a thin film having a small area formed on a substrate by flowing an electric current in parallel with the film surface, and is generally called a surface conduction electron-emitting device. Has been.

As this surface conduction electron-emitting device, one using a SnO ₂ (Sb) thin film developed by Elinson et al., And "Sin Solid Films (T
"Hin Solid Films", published by 1972, Vol. 9, page 317, by the Au thin film announced by G. Dittmer, and "IE Trans. E. D.
Conf. ), 1975, p. 519, M. Hartwell and Von Stud (C.
G. Fonstad) co-authored ITO thin film, and “Vacuum” 1983, Vol. 26, No. 1, page 22, carbon thin film announced by Hisashi Araki et al. A typical device configuration of these surface conduction electron-emitting devices is shown in FIG. In FIG. 1, 1 and 2 are electrodes for electrical connection, 3 is a thin film made of an electron emitting material, 4 is a substrate, and 5 is an electron emitting portion.

Conventionally, in these surface conduction electron-emitting devices, an electron-emitting portion is formed in advance by an energization process called forming before the electron emission. That is, by applying a voltage between the electrode 1 and the electrode 2, the thin film 3 is energized, and the thin film 3 is locally destroyed, deformed or altered by the Joule heat generated thereby, so that the thin film 3 has an electrically high resistance. The electron emission function is obtained by forming the electron emission portion 5 in the state.

Further, the emission characteristics of electron emission of the above device,
That is, a substrate coated with a phosphor is used on the above-mentioned device so that the spread area of the emitted electrons can be visually measured. In FIG. 1, 6 is a phosphor substrate and 7 is light emitted by emitted electrons. It is a department.

Regarding the emission characteristics of electron emission of the above-mentioned device, the phosphor substrate 6 is arranged in a space apart from the above-mentioned device by about several mm, and a voltage of several hundred V to several thousands V is applied to the electrode 1 and the electrode. When a driving voltage is applied between the two to emit electrons, the light emitting portion 7 has an elongated shape in which L (length) is larger than W (width) on the phosphor substrate 6, as shown in FIG. Show.

The emission characteristic is a characteristic peculiar to an electron-emitting device represented by a surface conduction electron-emitting device including the above-mentioned device.

Conventionally, an example of an image forming apparatus using an electron source in which the above elements are arranged in a line is shown in FIG.
As shown in FIG. 4, each electron-emitting portion 5 of the above device constitutes a point emission line electron source in which the electron-emitting portions 5 are linearly arranged in a line.
As described above, the phosphors of three colors of red (R), green (G), and blue (B) are sequentially arranged on the electron-emitting portions 5 of the above-mentioned elements arranged on the same line to form an image forming apparatus. Was.

[0010]

However, in the above-mentioned conventional example, the phosphors of each color are provided along the major axis direction of the elliptical light emitting portion 7 formed by the irradiation of the electron beam from the electron emitting portion of each electron emitting element. Are sequentially and regularly arranged, so if a picture element composed of three pixels of red (R), green (G), and blue (B) arranged in this way is formed,
Further, the picture element becomes horizontally long, and the picture element cannot be formed with high density in the line direction.

Therefore, the electron-emitting device has a simple structure, and although it is easy to construct an image forming apparatus using an electron source in which a plurality of electron-emitting devices are arranged, it is applied industrially positively. It has not been reached.

In view of the above circumstances, the present invention has a high density of picture elements in an image forming apparatus using an electron-emitting device, such as the surface-conduction electron-emitting device, having a particularly elongated light emitting portion as an electron source. As a result, the purpose is to increase the density and definition of the displayed image.

[0013]

The constitution of the present invention made to achieve the above object is as follows.

That is, the present invention is an image forming apparatus provided with a plurality of phosphors exhibiting mutually different emission colors and an electron source having a plurality of electron-emitting devices for irradiating the phosphors with an electron beam. An image forming apparatus is characterized in that a plurality of phosphors exhibiting a luminescent color are arranged along a minor axis direction of a shape of a light emitting portion formed by irradiating the phosphor with an electron beam.

The present invention is further characterized in that the shape of the electron-emitting portion of each of the plurality of electron-emitting devices is controlled according to the emission color of each of the plurality of phosphors. An electron-emitting device that forms an elongated light-emitting portion by irradiating a phosphor with an electron beam. The electron-emitting device is an electron-emitting device having an electron-emitting portion between electrodes arranged in parallel on a substrate. That the electron-emitting device is an electron-emitting device having a thin film including an electron-emitting portion between electrodes juxtaposed on a base, and the electron-emitting device is a surface conduction electron-emitting device. It also includes.

[0016]

EXAMPLES AND OPERATION The present invention will be described in detail below with reference to examples.

2 and 3 show an embodiment of the present invention. 2 is an explanatory view of the surface conduction electron-emitting device used in this embodiment, and FIG. 3 is an explanatory view of the image forming apparatus. In these drawings, the same parts as those in FIGS. 1 and 4 are equivalent members. Is represented.

In FIG. 2, quartz is used as the insulative substrate 4, Ni is used as the material for the electrodes 1 and 2 on the cleaned quartz substrate 4, and a film thickness of 1000 Å is formed by EB vapor deposition to form a photolithography technique. As a result, the electron emission portion 5 becomes w = 300 μm, 200 μm, 100 μm, G = 2
An electrode portion having a shape of μm was formed.

As the conductive material for forming the electrodes 1 and 2, other metallic materials such as Pt, Au, Cu, Al, and general conductive materials can be used.

Then, in order to dispose and form the fine particles 8 serving as an electron emitting material between the electrodes 1 and 2, a primary particle size of 80-2
00Å SnO ₂ dispersion (SnO ₂ : 1 g, solvent MEK
/ Cyclohexane = 3: 1: 1000 cc, butyral: 1 g) was applied by a spin coating method and heat-treated at 250 ° C.

The electron emitting portion is not limited to the above-mentioned fine particles, but can be formed by a thin film as described above. As the electron emitting material, In ₂ O ₃ , SnO
₂ , metal oxides such as PbO, metals such as Au and Ag, carbon, and various other semiconductors can be used.

Next, soda lime glass was used as a transparent glass substrate, and a transparent electrode ITO (In ₂ O ₃ : SnO ₂ = 9) was used.
5: 5) is formed by vapor deposition to 1000 Å, a phosphor that emits light by electrons is applied to form a phosphor substrate 6, and this phosphor substrate 6 is placed in a space of H = 5 mm of the above element, The release profile was measured.

Specifically, a voltage of 1000 V is applied to the phosphor substrate 6, a driving voltage of 14 V is applied to the above-mentioned element to emit electrons, and the current value of the electron beam with which the phosphor substrate 6 is irradiated and the fluorescence The area (electron emission region) of the light emitting portion 7 where the phosphor of the body substrate 6 emitted light was measured. As a result, when w = 300 μm of the electron emitting portion 5, the current value Ie = about 1.0 μm
When A, w = 200 μm, Ie = about 0.67 μA, w
= 100 μm, Ie = about 0.33 μA was obtained, and w and Ie of the electron emitting portion 5 were linearly changed. Also,
As shown in FIG. 2, when the light emitting unit 7 has w = 300 μm, W
(Width) = about 0.5 mm, L (length) = about 0.8 mm, w
= 200 μm, W = about 0.4 mm, L = about 0.7
mm, w = 100 μm, W = about 0.3 mm, L =
A light emitting portion of about 0.6 mm was obtained.

Next, before forming an electron source by using a plurality of the above elements and further forming an image forming apparatus, the w dimension of the electron emission portion of each element is determined according to the emission color of the phosphor corresponding to each element. To decide. The phosphor used in this example is an emission type by electron beam excitation, red is registration number P22, composition Y ₂ O ₂ S: Eu ³⁺ , efficiency is about 13%, green is registration number P.
22, composition ZnS: Cu, Al, efficiency about 23%, blue is registration number P22, composition ZnS: Cu, Al, efficiency about 21
% (Registration number is JEDEC (Joint El
by the Electron Device Committee). In order to obtain the same brightness for all three colors with the phosphors having different efficiencies, the w of the electron emitting portion 5 is changed for each line element corresponding to each phosphor. That is, the same brightness is obtained by changing the current value of the emitted electron beam. First, a driving voltage of 14 V was applied to the above device to obtain an emission current of 1 μA, and the luminance of the red phosphor was made to emit light,
In order to make the brightness of the green and blue phosphors the same, the electron emission part w is determined from the relationship between the efficiency of the phosphors, the emission current value, and the electron emission part w. Red: green: blue = 1/1
3%: 1/23%: 1/21% = 1.0 μA: 0.56
μA: 0.62 μA = 300 μm: 168 μm: 186
μm.

FIG. 3 (a) is an explanatory view showing a surface conduction electron-emitting device using the above-mentioned device and arranged regularly in a line and in multiples. FIG. 3 (b) is arranged on the phosphor substrate 6. It is explanatory drawing which showed the color and structure of the said fluorescent substance, and the light emission part 7.

In FIG. 3 (a), L of the light emitting portion 7 formed by an element in which w of the electron emitting portion 5 is 300 μm is about 0.8 m.
Since it is m, the element spacing between adjacent lines is 1.
It was set to 0 mm so that the light emitting portions 7 did not overlap. In addition, the electron emission portion 5 of the element corresponding to the red phosphor is set to w =
At 300 μm, the electron emission portion 5 of the element corresponding to the green phosphor is set to w = 168 μm, and the electron emission portion 5 of the element corresponding to the blue phosphor is set to w = 186 μm. Six elements each having the electron-emitting portion 5 having the above-mentioned shape corresponding to the body were sequentially arranged on one line, and the same line-shaped element was constituted in three lines as a whole.

Next, as shown in FIG. 3 (b), phosphors of the colors corresponding to the respective elements of the electron emitting portion 5 having different w are arranged at the same intervals as the element intervals of the above-mentioned multi-element. The body substrate 6 was constructed.

Then, in the same manner as the above, the phosphor substrate was placed in the space above the substrate on which the multi-element was formed, to form an image forming apparatus.

In the image forming apparatus of the present invention configured as described above, since phosphors exhibiting different emission colors are arranged along the minor axis direction of the light emitting portion 7, adjacent red and green on the same line are arranged. If one picture element is composed of blue three-color phosphors, in the conventional example, only a picture element that is long in the lateral direction can be formed, whereas a picture element that is closer to a square can be formed.
The pixel density can be dramatically increased.

Further, when 6 elements × 3 lines were simultaneously electron-emitted and the phosphors were made to emit light under the same driving conditions as the one element, as shown in FIG. The body was able to emit light with uniform brightness.

[0031]

As described above, according to the present invention,
In an image forming apparatus including a plurality of phosphors exhibiting mutually different emission colors and an electron source having a plurality of electron-emitting devices for irradiating the phosphors with an electron beam, a plurality of phosphors exhibiting mutually different emission colors, By arranging along the minor axis direction of the shape of the light emitting portion formed by irradiating the phosphor with the electron beam, even when an electron-emitting device in which the light emitting portion has an elongated shape is used as an electron source, the pixel It is possible to achieve high density and high density / high definition display images.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a surface conduction electron-emitting device which is an example of an electron-emitting device according to the present invention.

FIG. 2 is a diagram illustrating a surface conduction electron-emitting device according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining the arrangement of electron-emitting devices and phosphors in the image forming apparatus according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 1, 2 electrodes 3 thin film 4 substrate 5 electron emission part 6 phosphor substrate 7 light emitting part 8 fine particles

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tetsuya Kaneko 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hidetoshi Haru 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Haruto Ono 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. An image forming apparatus comprising: a plurality of phosphors exhibiting mutually different emission colors; and an electron source having a plurality of electron-emitting devices for irradiating the phosphors with electron beams, wherein the emission colors are different from each other. An image forming apparatus, wherein the plurality of phosphors are arranged along a minor axis direction of a shape of a light emitting portion formed by irradiating the phosphor with an electron beam. 2. The image forming apparatus according to claim 1, wherein the shapes of the electron emitting portions of the plurality of electron emitting devices are controlled according to the emission colors of the plurality of phosphors. 3. The image forming apparatus according to claim 1, wherein the electron-emitting device is an electron-emitting device that forms an elongated light-emitting portion by irradiating a phosphor with an electron beam. 4. The image forming apparatus according to claim 1, wherein the electron-emitting device is an electron-emitting device having an electron-emitting portion between electrodes arranged in parallel on a substrate. . 5. The electron emitting device according to claim 1, wherein the electron emitting device is an electron emitting device having a thin film including an electron emitting portion between electrodes arranged in parallel on a substrate. Image forming apparatus. 6. The image forming apparatus according to claim 1, wherein the electron-emitting device is a surface conduction electron-emitting device.